EMP Chapter 9-16 - Arunachal Pradesh State Pollution Control ...

DEMWE LOWER HE PRJECT (1750 MW) 

CREATION OF GREEN BELT AROUND THE RESERVOIR 

9.1 INTRODUCTION 

The proposed dam of 163.12 m (above deepest foundation) height at Parasuram 

Kund will create a reservoir of around 1131 ha area. The length of the reservoir 

will be around 23 km along the Lohit river. Around 50% of the reservoir area at 

present is covered with forest of dense or open type. Slopes along the river are 

mostly stable. Some areas around the reservoir are under cultivation or have 

scrub forests, which are the main source of silt to the reservoir. Creation of green 

belt has been proposed around the reservoir of Demwe Lower H.E. Project to 

reduce the silt flow in the reservoir and thus increase its life. The area taken for 

the creation of green belt is around 2887.8 ha along the periphery of the reservoir 

and the budget allocated for this purpose is around Rs. 91.45 lakhs. 

9.2 OBJECTIVES 

Main objectives of creating a green belt around a reservoir are to i) check soil 

erosion around the reservoir, ii) check landslides and slips around the reservoir, 

and iii) develop the habitat for wildlife particularly birds and butterflies. Besides 

these objectives, development of lake view points and creation of recreation sites 

along the reservoir rim are two additional aspects. Development of green belt 

around the reservoir will also improve the habitat of birds and other wild animals 

around the region. Planting of trees, shrubs and other plant species in the region 

will definitely improve the environment of the region besides checking the soil 

erosion. 

9.2.1 Green Belt Structure and Development Planning 

In the proposed Demwe Lower H.E. Project, the area taken for the development 

of green belt around the reservoir is around 2887.8 ha. This area has been 

divided into three layers for plantation of plant species depending upon the 

Environmental Management Plan – Creation of Green Belt around the Reservoir 

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9 

9-1


microclimatic condition that will develop after creation of the reservoir in the 

region (Fig. 9.1). Various engineering and bioengineering measures for the 

stabilization of the region around reservoir rim will be applied under the proposed 

CAT plan of Demwe lower HE project and, therefore, have not been considered 

here. Emphasis has been given here for plantation to develop the green belt. 

Covering of the area with vegetation will check soil erosion and flow of the silt to 

the reservoir. 

In the proposed green belt area, more than 37% of the total area is covered with 

dense forest. The open forest, degraded forest and scrub forest together cover 

nearly 56% of the area. (Table 9.1). A detailed plan is given for greening the 

reservoir rim. Entire green belt is divided into three layers, G1, G2 and G3 with 

total land area of 2888 ha. The first layer (G1) is bottommost layer immediately 

above submerged area and G3 layer is the topmost layer. The bottom layer 

starts at 425 m contour and covers an area of 688.74 ha up to 500 m contour 

line. The width of this layer varies from a minimum of 26.72 to 473.89 m. The 

micro climate of the layer will be very humid, and therefore, water loving plant 

species like Albizia odoratissima, Bischofia javanica, etc. are suggested for 

plantation (Table 9.2). 

Layer G2 starts at contour 500 m and covers an area up to 600 m contour line. 

The total area within the layer is around 1051.24 ha. The micro climate of the 

layer will be slightly different than the G1 layer. The plants suggested for 

plantation in the region are Aesculus assamica, Alangium chinense, Bambusa 

tulda, Centella asiatica (Table 9.2) 

The topmost layer (G3) is suggested from contour 600 m and can extend up to 

700 m or more, area covered is around 1147.84 ha. The micro climate in this 

layer will be slightly drier than the two inner layers. Plant species like Butea 

monosperma, Castanopsis indica, Asparagus raccmosus, Ajuga bracteosa, etc. 

are suggested for the plantation in this layer (Table 9.2).The open forest, scrub 

forest and degraded forest lands of each layer need plantation. These forests 


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land together constitute 352.91, 595.06, 655.78 ha in G1, G2 and G3 layer, 

respectively (Table 9.1). 

Table 9.1: Land use/land cover of different green belt layers 

Land use/ Land cover Bottom layer (ha) Middle layer (ha) Top layer (ha) 

categories 

Dense forest 244.34 391.69 455.55 

Open forest 240.12 420.24 467.33 

Scrub 18.5 31.34 38.26 

Degraded forest 94.29 143.48 150.19 

Cultivation 32.42 28.39 21.48 

Landslide 7.65 11.31 3.28 

River water-body 42.33 24.79 10.95 

Sand 9.09 - 0.80 

Total 688.74 1051.24 1147.84 

Area to be treated 352.91 595.06 655.78 

(Open forest, scrub, degraded forest) 

Green Belt 

Layers 

Layer G1 

Table 9.2: Plantation layout for the Green Belt 

Area (ha) Elevation 

(m) 

688.74 425-500 

Some major plant species for the Plantation 

Trees:, Albizia odoratissima, Artocarpus 

chaplasha Bischofia javanica, Dillenia indica, 

Oroxylum indicum, Rhus succadanea, etc. 

Shrubs: Alsophila spinulosa, Calamus 

floribundus, Dendrocalamus hamiltonii, 

Debregeasia longifolia, Ipomoea carnea, Pinanga 

gracilis, etc. 

Herbs: Coix lacryma-jobi, Cynodon dactylon, 

Hedychium coccineum, Imperata cylindrica, Piper 

pedicellatum, Saccharum elephanticus, S. 

spontaneum, Thysanolaena latifolia, etc. 

Trees: Aesculus assamica, Alangium chinense, 

Altsonia scholaris, Artocarpus lacucha, Bauhinia 


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Green Belt 

Layers 

Layer G2 

Layer G3 

Area (ha) Elevation 

(m) 

1051.24 

1147.84 

500-600 

600-700 

Some major plant species for the Plantation 

purpurea, Canarium strictum, Magnolia hodgsonii, 

Moringa oleifera, Terminalia myriocarapa, T. 

bellerica, Ulmus lancifolia, etc 

Shrubs: Agave sisalana, Bambusa tulda, B. 

nutens, Dendrocalamus hamiltonii, Jatropha 

curcas, Manihot esculenta, Vitex negundo, etc. 

Herbs: Achyranthes aspera, Centella asiatica, 

Chlorophytum arundinaceum, Cymbopogon 

flexuosus, Saccharum spontaneum, etc. 

Trees: Albizia lebbeck, A. Procera, Butea 

monosperma, Castanopsis indica, Cinnamomum 

pauciflorum, Crateva unilocularis, Engelhardtia 

spicata, Magnolia hodgsonii, Mesua ferrea, 

Michelia kisopa, Saurauia roxburghii, Spondias 

pinnata, etc. 

Shrubs: Asparagus racemosus, Bambusa tulda, 

Clerodendrum bracteatum, Calamus spp., 

Pinanga gracilis, Zanthoxylum armatum, etc. 

Herbs: Ajuga bracteosa, Artemisia indica, Begonia 

palmata, Bergenia ciliata, Chrysopogon gryllus, 

Pennisetum purpureum, Saccharum spontaneum, 

etc. 

Total area proposed for greening around the reservoir rim is around 2887.8 ha 

and the budget proposed is Rs. 91.45 lakhs. 

9.3 SCHEDULE 

The construction period of the project is around 60 months. All engineering 

measures like construction of retaining walls, crate walls, stream bank 

treatments, etc to stabilize landslips around reservoir will be carried out under the 

CAT plan. Plant sapling will be required for biological treatment measures. 

Plantation and maintenance will be carried out between 18-54 months from the 

date of inception of the projects. Between 1-18 months all the engineering and 

bioengineering measures for stabilization of slopes will be carried out under the 

proposed CAT plan. 


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9.4 BUDGET 

The budget allocated for different components of green belt like preparation of 

pits, manure, raising saplings, etc. is around Rs. 91.45 lakhs (Table 9.3). The 

budget also includes maintenance of the executed work. 

Table 9.3: Physical and financial break up for the creation and maintenance of green belt 

around the reservoir of Demwe Lower HE project 

Item (G3) I st layer (G1) II nd layer (G2) III rd layer 

(18-30 months) 

area: 352. 91 (ha) 

Biological measures (Afforestation and Maintenance) 

30-42months) 

area: 595. 06 (ha) 

1. Pitting 

i) Physical (Nos.) 35291 

(@100pits/ha) 

(size of pit:0.45m*0.45m*0.45m) 

59506 65578 

ii) Financial (Rs Lakh) 11.7 

(@Rs33.08/pit) 

2. Manure and imported soil 

19.7 21.7 

i) Physical (Nos.) 35291 59506 

(@100pits/ha) 

65578 

ii)Financial (Rs. lakh) 1.41 

(@Rs 4/pit) 

3. Raising plants 

2.38 2.62 

i) Physical (Nos) 35291 

(@100 plants/ha) 

59506 65578 

ii)Financial (Rs. lakhs) 6.70 

(@Rs18.98/plant) 

11.29 12.45 

4. Watering, maintenance 0.40 

and transport (Lumsum) 

0.50 0.60 

Total (Rs. lakhs) 20.21 33.87 37.37 

Grand Total (Rs. lakhs) (G1+G2+G3) = 91.45 


(42-54 months) 

area: 655.78 (ha) 

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9-5

Proposed green belt around the submergence area of Demwe Lower H.E. project 

Figure 9.1


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10 

REHABILITATION & RESETTLEMENT PLAN 


Proposed Demwe Lower H.E. project is located in the Lohit and Anjaw districts of 

Arunachal Pradesh. The project envisages construction of 163.12 m high 

concrete gravity dam with a dam-toe power house to generate 1750 MW 

electricity. The reservoir likely to be created upon construction of project would 

submerge a total area of 1131 ha. The project area is dominated by Mishmi and 

small patches by Khampti tribes. These tribes are known to dwell in compact 

areas, follow a community way of living, remain very close to the nature and have 

a uniqueness of culture, distinctive customs, traditions and beliefs. These 

communities are well known to practice jhum cultivation and have traditional 

rights and privileges on forested areas. Considering the legal position and 

community rights into consideration, a PROPERTY SURVEY was undertaken by 

the State Government of Arunachal Pradesh in the project area from March 2008 

to October 2008 at the request of the project proponents. Based on the property 

survey findings, it was observed that such land belongs to the Project Affected 

Families of 23 villages within 3 administrative circles. Only five villages, viz. 

Paya, Chipragam, Dingliang, Tidding and Lakoa are revenue villages whereas 

remaining villages (Chaigadiliang, Pumla, Dumla, Tyulliang, Challing, Taseliang, 

Kangkhai, Langmeh, Netoh, Pram, Langliong, Rangam, Bajiliang, Dowamma, 

Aoliang, Haloiang and Tangam) are considered as hamlets. Baseline status of 

socio-economic environment in respect of all the project affected families of 

Demwe Lower hydroelectric project was evaluated for population status, social 

and cultural environment, land holdings and other parameters. The baseline data 

for project-affected families was collected from field surveys by conducting doorto-door 

socio-economic survey. 

Environnemental Management Plan – Rehabilitation & Resettlement Plan 

10-1


Generally, Resettlement and Rehabilitation Plan for the developmental project is 

framed out to minimize the negative impacts of the project, to satisfy project 

affected families or persons, to compensate the loss of livelihood of people, to 

consider all cultural, traditional and social aspects and to furnish infrastructure 

development in the project area. Thus, in case of Demwe Lower HEP, it was felt 

that R & R plan needs some careful considerations to strike a balance between 

preservation of tribal identity, culture and values, protecting the tribes from being 

swamped by mainstream lifestyles, while at the same time increasing and 

ensuring their access to mainstream education, health care and income 

generation so that their quality of life is improved. 

In order to formulate and implement the Rehabilitation and Resettlement Plan, a 

well defined National Policy on Rehabilitation and Resettlement provides the 

guidelines. However, a few States have their own Rehabilitation and 

Resettlement polices, which provides not only the better relief package but take 

care of the regional issues and aspirations. Arunachal Pradesh Government has 

recently finalized its R & R policy, which follows same definitions of expressions 

as provided in National Rehabilitation and Resettlement Policy, 2007 (NRRP- 

2007) except a few terms like ‘community’, ‘Affected area’ and ‘Jhum’. The 

proposed Rehabilitation and Resettlement Plan for Demwe Lower (1750 MW) HE 

project is prepared considering the NRRP, 2007 and Rehabilitation and 

Resettlement Policy of Arunachal Pradesh State Government (2008) and the 

draft National Policy for the Scheduled Tribes, Govt of India which outlines 

measures for Local Area Development Plan (LADP) also. Comparing these 

policies, the better options have been suggested in the proposed R&R package 

and LADP. Table 10.1 presents a summarized overview on the financial 

provisions that are suggested in the proposed R&R package and LADP vis-à-vis 

the recommendations of NRRP, 2007, Arunachal State Policy (2008) and Draft 

Tribal Policy (2009). 


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Table 10.1: Comparative statement indicating R&R package and LADP adopted in 

formulating the proposal vis-à-vis provisions of NPRR, 2007 and Arunachal Policy, 2008. 

Item NRRP-2007 

Arunachal Pradesh State R & 

R Policy-2008 

Fishing rights 7.5 (a) In the case of 8.14.3: The tribal families 

irrigation or hydel residing in the project affected 

projects, fishing rights in areas having fishing rights in the 

the reservoirs shall be river/ponds/dam shall be given 

given to the affected fishing rights in the reservoir 

families, if such rights area And also under section 

were enjoyed by them in 

the affected area; (b) In 

other cases also, unless 

there are special 

reasons, fishing rights 

shall be given 

preferentially to the 

affected families. And 

also under section 

7.21.10: 

8.14.3 

Compensation No such Provision 8.5.1: Compensation for trees 

for trees on 

standing on the acquired 

agriculture 

agriculture land would be 

land 

payable to the entitled land 

owner families as per valuation 

done by the state 

authority/Horticulture department 

as per the guidelines and 

principles as ma / be laid down 

by the state government. 

Vulnerable 7.17: The project 8.12.1: The project authorities 

person grant authorities shall, at their shall, at their cost, arrange for 

cost, arrange for annuity annuity policies that will pay a 

policies that will pay a pension of Rs 500/- per month 

pension for life to the for life to the vulnerable affected 

vulnerable affected persons as indicated at 

persons as indicated at 

paragraph 6.4(v), of such 

paragraph 7.1.6 (iv) of this policy 


ADPPL Suggested 

Provisions 

Fishing rights will be 

allowed 

Rs 7,97,450 will be 

payable to the eligible 

land owners as per the 

property survey 

Pension of Rs. 500/- per 

month for lifetime to 

vulnerable affected 

person such as widows, 

unmarried adult women, 

all those above 50 years 

of age without family 

support for 60 persons 

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R Policy-2008 


Provisions 

amount as may be 

prescribed by the 

appropriate Government 

subject to a minimum of 

Rs 500/month. 

totaling Rs 1,80,00,000/- 

Free 

No Such Provision 8.14.5: The project developers Free Electricity grant of 

electricity to 

will provide to each of the project 100 units per month for 

PAF 

affected families the benefit of PAF’s for 10 year for 

100 units of electricity per month 204 No. of families @ 

free of charge for a period of 10 Rs. 5.00/unit (lump sum 

years from the date of 

rate) totaling Rs 

commissioning of a hydroelectric 

project and arrange this benefit 

through the concerned 

distribution company. In case of 

the affected family not 

consuming 100 units, of 

electricity the cost of balance 

unused units shall be made 

available to the family in cash or 

kind or combination of both as 

per the hydropower policy of the 

State Government. 

1,22,40,000/- 

ST family 7.21.5: In case of a No such Provision Scheduled Tribe family 

compensation project involving land 

grant for 204 families @ 

acquisition on behalf of a 

Rs. 50,000, totaling to 

requiring body, each 

Scheduled Tribe affected 

family shall get an 

additional one-time 

financial assistance 

equivalent to five 

hundred days minimum 

agricultural wages for 

loss of customary rights 

or usages of forest 

Rs 1,02,00,000/- 


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Land 

compensation 

produce. 

Provision as per the land 

Acquisition 


R Policy-2008 

(ii) the Deputy commissioner in 

his capacity as forest settlement 

officer assisted by land revenue 

department and settlement 

officer, shall work our 

compensation for the loss of 

rights and privileges of the tribal 

people to collect and use forest 

produce from USF @ Rs 

1,56,000/ha for USF area and 

Rs 78,000/ha for RF (if any 

rights and privileges are granted 

by notification constituting RF) 

for the base year 2008 as on 1- 

4-2008 

(iii) in addition, in case of 

diversion of USF, the community 

shall also be paid compensation 

against extinction of their 

traditional rights over the USF 

land use @ 25 % of NPV as 

determined by GOI from timer to 

time. This compensation is over 

and above the NPV paid to 

CAMPA. 


Provisions 

1. Reserve Forest Land 

- Rs 78,000 per ha 

2. USF/Community 

Forest Land - Rs 

1,56,000 per ha+ 25 

% NPV 

3. Community Jhum 

Land/Community 

Land - Rs 1,75,000 

per ha + 30 % 

Solatium of land value 

4. Cost of Crops in Hilly 

area - Rs 1,00,000 

per ha 

5. Cost of Crops in Plain 

area - Rs 1,20,000 

per ha 

Total Cost of Land Value 

Rs 21,11,70,600 

calculated as per the 

property survey. 

10.2 OBJECTIVES OF THE RESETTLEMENT AND REHABILITATION PLAN 

(R&R PLAN) 

The objectives of the Resettlement and Rehabilitation Plan are to: 

• Provide assistance and other support to the PAF’s so that they regain their 

previous standard of living; even improve if possible, within a reasonable 

transition period. 

• Pay compensation for the loss of land, houses and all other immovable 

properties to the PAF’s as per the Land Acquisition Act (LAA). This is 


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done primarily as there is no other National Law under which Project 

authority can acquire land for the construction of projects. Besides, the 

Land Acquisition Act, 1894 has laid down certain norms for compensation 

for acquisition of private property. 

• Improve the quality of life, activities connected with primary education, 

primary health care, women and child welfare, care of the aged & destitute 

can be organized. 

• Assist the PAF’s in regaining their economic status in the initial stages in 

such a way that they can sustain on their own and do not have to depend 

on the project authorities for long. The project authorities can slowly 

phase-out their assistance and leave the PAF’s to depend on their own 

economic activities and social lifestyle. 

The process of R&R has two distinct components namely rehabilitation and 

resettlement. Rehabilitation primarily means to assist the affected population so 

that every individual could regain or improve lifestyle and socio-economic 

condition. This is done primarily by imparting skills and/or vocational training to 

the PAP’s. Resettlement on the other hand, primarily involves the physical 

relocation of the affected population to a new residential site. 

The Rehabilitation package is conceptualized around a development strategy to 

bring about a positive socio-economic transformation of the PAF’s, so as to 

improve the quality of their life. This is done primarily through the following 

measures: 

• Provision of alternate jobs/ vocational training 

• Opportunities to avail the facilities of training in various trades 

And last but not the least, acquisition of land would have to be compensated in 

accordance with the Land Acquisition Act, 1894 and provisions laid in the 

National Rehabilitation Resettlement Policy -2007 & , Arunachal State Policy 

(2008). 


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10.3 APPROACH 

Under the proposed Rehabilitation and Resettlement Plan, it has been 

emphasized that the project shall play a positive role in their socio-economic 

upliftment and also for betterment of quality of life of tribes. In addition to the 

rightful compensation, the provisions of Rehabilitation and Relief and Local Area 

Development Programme (LADP) have been therefore proposed. Individual land 

holding details in the affected area were assessed by the State Government at 

the request of Project Proponents through a Property Survey which has been 

detailed in Socio-economic baseline data. 

Subsequently, all the families, having rights on the proposed land to be acquired 

were considered as affected families. A detailed questionnaire was prepared for 

conducting detailed socio-economic survey among the PAF’s. 

For the maximum benefit of the affected families Rehabilitation and Resettlement 

package has been prepared considering the various policies like National 

Rehabilitation Resettlement Policy (NRRP) 2007, Rehabilitation and 

Resettlement policy of Arunachal Pradesh Government (2008) and the draft 

National Policy for the Scheduled Tribes, Govt of India and the best option 

among the policies has been selected. Only the relevant provisions under the 

various policies have been mentioned below, similar provisions of different 

policies are not repeated for sake of brevity and similarly the monetary 

references having higher values have been taken. It is worth mentioning here 

that due to the various project activities, none of the family is to be displaced; 

therefore, only relief and rehabilitation measures along with Local Area 

Development Programmes are taken into account. 

10.3.1 Definitions 

The various terms except ‘community’, ‘jhum’ and ‘affected area’ defined by the 

R & R Policy of Arunachal Government (2008) are similar to the NRRP (2007). 

To provide better package, in the proposed R & R plan the terms ‘community’ 

and ‘jhum’ have been adopted from the R & R policy of Arunachal Govt. The term 


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‘affected area’ has been defined according to NPRR (2007). The various terms 

which are relevant to the proposed project are described in following paragraphs 

(a) "Administrator for Rehabilitation and Resettlement" means an officer not 

below the rank of District Collector in a State appointed for the purpose of 

rehabilitation and resettlement of affected persons. 

(b) "Affected family" means: 

(i) a family whose primary place of residence or other property or source of 

livelihood is adversely affected by the acquisition of land for a project or 

involuntary displacement for any other reason or 

(ii) any tenure holder, tenant, lessee or owner of other property, who on 

account of acquisition of land (including plot in the abadi or other 

property) in the affected area or otherwise, has been involuntarily 

displaced from such land or other property; or 

(iii) any agricultural or non-agricultural labourer, landless person (not having 

homestead land, agricultural land, or either homestead or agricultural 

land), rural artisan, small trader or self-employed person; who has been 

residing or engaged in any trade, business, occupation or vocation 

continuously for a period of not less than three years preceding the date 

of declaration of the affected area, and who has been deprived of 

earning his livelihood or alienated wholly or substantially from the main 

source of his trade, business, occupation or vocation because of the 

acquisition of land in the affected area or being involuntarily displaced for 

any other reason. 

(c) "Affected area" means area of village or locality notified by the appropriate 

Government under paragraph 6.1 of this policy; 

(d) "Agricultural labourer" means a person primarily resident in the affected 

area for a period of not less than three years immediately before the 

declaration of the affected area who does not hold any land in the affected 

area but who earns his livelihood principally by manual labour on 

agricultural land therein immediately before such declaration and who has 

been deprived of his livelihood. 


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(e) "Agricultural land" includes lands being used for the purpose of 

(i) agriculture or horticulture; 

(f) 

(ii) dairy farming, poultry farming, pisciculture, breeding of livestock or 

nursery growing medicinal herbs; 

(iii) raising of crops, grass or garden produce; and 

(iv) land used by an agriculturist for the grazing of cattle, but does not 

include land used for cutting of wood only; 

"Appropriate Government" means,- 

(i) in relation to the acquisition of land for the purposes of the Union, 

the Central Government; 

(ii) in relation to a project which is executed by the Central 

Government agency or undertaking or by any other agency on the 

orders or directions of the Central Government, the Central 

Government; 

(iii) in relation to the acquisition of land for purposes other than (i) 

and (ii) above, the State Government; and 

(iv) in relation to the rehabilitation and resettlement of persons 

involuntarily displaced due to any other .reason, the State 

Government; 

(g) 'BPL family The below poverty line (BPL) families shall be those as 

defined by the Planning Commission of India from time to time and 

included in a BPL list for the time being in force. 

(h) "Commissioner for Rehabilitation and Resettlement" means the 

i) 

Commissioner for Rehabilitation and Resettlement appointed by the State 

Government not below the rank of Commissioner' or of equivalent rank of 

that Government. 

"family" includes a. person, his' or her spouse, minor sons, unmarried 

daughters, minor brothers, unmarried sisters, father, mother and other 

relatives residing with him or her and dependent on him or her for their 

livelihood; and includes "nuclear family" consisting of a person, his or her 

spouse and minor children. 


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10-9


(j) "Holding" means the total land held by a person as an occupant or tenant 

or as both. 

(k) "Land acquisition" or "acquisition of land" means acquisition of land under 

the Land Acquisition Act, 1894 (1 of 1894), as amended from time to time, 

or any other law of the Union or a State for the time being in force. 

(l) "marginal farmer" means a cultivator with an un-irrigated land holding up 

to one hectare or irrigated land holding up to half hectare. 

(m) "non-agricultural labourer" means a person who is not an agricultural 

labourer but is primarily residing in the affected area for a period of not 

less than three years immediately before the declaration of the affected 

area and who does not hold any land under the affected area but who 

earns his livelihood principally by manual labour or as a rural artisan 

immediately before such declaration and who has been deprived of 

earning his livelihood principally by manual labour or as such artisan in the 

affected area. 

(n) “Notification" means a notification published in the Gazette of India or, as 

the case may be the Gazette of a State. 

(o) "Occupiers" mean members of the Scheduled Tribes in possession of 

forest land prior to the 13 th day of December, 2005; 

(p) "project" means a project involving involuntary displacement of people, 

irrespective of the number of persons affected; 

(q) "requiring body" means a company, a body corporate, an institution, or 

any other organisation for whom land is to be acquired by the appropriate 

Government, and includes the appropriate Government if the acquisition 

of land is for such Government either for its own use or for subsequent 

transfer of such land in public interest to a company, a body corporate, an 

institution, or any other organization, as the case may be, under lease, 

license or through any other system of transfer of land; 

(r) "small farmer" means a cultivator with an un-irrigated land holding up to 

two hectares or with an irrigated land holding up to one hectare, but more 

than the holding of a marginal farmer. 


10-10 

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10.4 LAND REQUIREMENT AND COMPENSATION 

Total land required for the various project components viz. dam structure, power 

house structure, submergence, colony development etc. is 1589.97 ha. It 

includes community forest land/reserved forest land of 1087.05 ha of which 

652.18 ha falls under submergence and 434.87 ha is required for various project 

components. 

S.NO Land Classification Land, Ha 

1 Total Community Land Holding/Claim 1087.05 

a Community Jhum land (Agricultural/Horticultural area) 174.05 

b Community Forest land 720.25 

c Reserved Forest 192.75 

2 Forest Department (Riverbed/Waterbody) 502.92 

Grand Total 1589.97 

The communities’ livelihood depends on the 1087.05 ha land to be acquired, 

therefore, rightful and rehabilitation compensation will be provide for the same 

land only. (Table 10.2) 

Table 10.2: Abstract of Land Requirement for Demwe Lower HEP 

S No Project component Area (ha) River Bank Legal Status 

A Surface Structures 

1 Dam Complex Area 

a River Bed 12.01 Riverbed 

b Surface Area 

i) L/B Lohit dam axis 4.32 L/B Lohit 

ii) R/B Lohit dam axis 12.13 R/B Lohit 

2 

Power House Complex 

Area including Tail Race 

21.59 R/B Lohit 


Kamlang Reserved 

Forest 

Community Forest 

Land 


Land 

10-11 

CISMHE


3 

tunnel & Pressure shaft 

Muck Dumping 

Area/Stack Yard 

150 L/B Lohit 

4 Magazine Area 5 R/B Lohit 

5 

6 

Crusher Plant & batching 

plant -1 

Crusher Plant & batching 

plant -2 and 3 

7 Construction facilities 

5 R/B Lohit 


a Equipment 25.47 L/B Lohit 

b Workshop 5 L/B Lohit 

c Steel yard 13 L/B Lohit 

d Fabrication yard 13 L/B Lohit 

e Labour Camp 36 L/B Lohit 

f Office setup 3 L/B Lohit 

g Office Colony 5 L/B Lohit 

8 Permanent Colony Area 60 L/B Lohit 

9 Approach Roads 

i) Left Bank Road (1) 5 L/B Lohit 

ii) Left Bank Road (2) 3 L/B Lohit 

Kanday Community 

Forest Land 


Land 


Land 


Land 


Forest Land 


Forest Land 


Forest Land 


Forest Land 


Forest Land 


Forest Land 


Forest Land 


Forest Land 


Land 


Land 

iii) R/B DT intake and quarry 9.84 R/B Lohit Community Forest 


10-12 

CISMHE


iv) 

area road Land 

R/B DT outlet and 

diversion road 

v) Tidding diversion Road 12.4 

10 

Quarry Area above 

Submergence (excluding 

36.47 ha of quarry area in 

submergence) 

2 R/B Lohit RF Dining 

R/B Lohit 

(R/B 

Tidding) 


Community Jhum 

Land 


Land 

11 DT outlet Area 6.73 R/B Lohit Dining RF 

12 Shoal Area 12 R/B Lohit River bed 

13 Submergence Area 

a River Bed 478.91 

b Surface/pondage 652.18 

B Under Ground Structures 

a 

Diversion Tunnel and 

Road tunnel 

i) Diversion Tunnel L/B Lohit 0.84 L/B Lohit 


Land 

Community 

Forest/Jhum 

Land/Kamlang RF 


Land 

ii) Diversion Tunnel R/B Lohit 2.67 R/B Lohit Dining RF 

iii) Diversion Tunnel R/B Lohit 4.11 R/B Lohit 

b 

Pressure shaft already 

included in PH area (3.8 

ha) 

15 Total 1589.97 



Land 

10-13 

CISMHE


In the case of Demwe Lower (1750 MW) HE project, no immovable asset is 

being either acquired or submerged, however, some of the communities are 

loosing their land holding partially. In this project, most of the project components 

are located at one place as it is a Dam toe power house project. Majority of the 

area being acquired is for: 

• Dam Complex Area 

• Roads 

• Muck Retaining Structures 

• Project Colonies & Work Spaces 

• Submergence 

The land to be acquired for the construction of roads would be useful to both, the 

project as well as the public as it would enhance their connectivity and improves 

their quality of life. The area to be acquired for dumping the muck would basically 

protect the environment of the project area in long run with the proposed 

interventions in the Restoration Measures. The land to be acquired for project 

colonies and work spaces are proposed to be acquired where relatively there is 

no habitation. However, it must be stated that once the infrastructure is 

developed, they would generate tremendous scope for indirect employment and 

economic opportunities to the people around these areas. 

10.4.1 Rehabilitation Grant for Affected Families 

10.4.1.1Compensation for land: 

The project components are located in the Lohit district with the reservoir 

extending partly in the Anjaw district of Arunachal Pradesh. No households are 

likely to lose their homestead due to the proposed project. No families are being 

landless as only small land of the community holding is being acquired. The 

village communities have expressed support to the project. All the tribal 

communities who are losing the land would be compensated as detailed below: 

a. Reserve Forest Land - Rs 78,000 per ha 

b. USF/Community Forest Land - Rs 1,56,000 per ha+ 25 % NPV 


10-14 

CISMHE


c. Community Jhum Land/Community Land - Rs 1,75,000 per ha + 30 % 

Solatium of land value + Cost of Crops ( in Hilly area - Rs 1,00,000 per 

ha or in Plain area - Rs 1,20,000 per ha) 

Table 10.3: Compensation for land acquisition in Demwe Lower HEP 

S. 

No. 

Village Ownership/claim 

A. Submergence Area 

No. 

of 

PAF’ 

s 

Area to be 

acquired, 

ha 

Compensati 

on, Rs 

1 Chailliang Tayang Clan 11 8.58 1501500.00 

2 Paya Tayang/Yun Clans 10 21.42 3748500.00 

3 Chipragam Yun/Towang Clans 6 10.6 1855000.00 

4 Dingaliang 

Tayang/Thalai 

Clans 

Tayang/Thalai 

Clans 

6 

19.41 3396750.00 

30.62 5358500.00 

5 Tidding Tayang Clan 9 34.89 3808000.00 

6 Taseliang Tayang Clan 2 15.15 2651250.00 

7 Chaigadiliang Thalai Clan 1 9.8 1715000.00 

8 Chaidheliang Tayang Clan 6 11.18 1956500.00 

9 Pumla 

Landuse 

CISMHE 

Community Jhum land 

(Agricultural/Horticultural) 

















Tayang 4 15.3 2386800.00 Community forest land 

Pong Clan 3 18.98 2960880.00 Community forest land 

Takaliang Clan 8.4 1310400.00 Community forest land 

14 

10 Dumla Takaliang Clan 

48.38 7547280.00 Community forest land 

11 Tyluliang Tayang Clan 17 78.21 

12 

13 

Lamaliang 

(Bajailiang) 

Dowamma Tayang Clan 

12200760.00 

Community forest land 

Tayang Clan 13 31.06 4845360.00 Community forest land 


3 

10.83 1689480.00 Community forest land 

10-15


S. 

No. 

Village Ownership/claim 

(Kajing) 

No. 

of 

PAF’ 

s 

Area to be 

acquired, 

ha 

Compensati 

on, Rs 

Landuse 

CISMHE 

Dowamma Tayang Clan 9.9 1544400.00 Community forest land 

14 Pram 

15 Lakao 

16 

Aogum Tayang Clan 13.41 1045980.00 Kamlang RF 

Yun/Tayang/ Don 

Clans 

Yun/Tayang/ Brap/ 

Bru Clans 

12 32.85 

5124600.00 

Community forest land 

8 12.29 1917240.00 Community forest land 

Fungo Mam Clan 9.79 763620.00 Kamlang RF 

Kangkhai Mam Clan 7.5 1170000.00 Community forest land 

Mitaw Mam Clan 6.53 509340.00 Kamlang RF 

24 

Khawmai Mam Clan 12.56 979680.00 Kamlang RF 

17 Aoliang 

Chingro Mam Clan 5.94 463320.00 Kamlang RF 

Ngalang Mam Clan 

Tayang/Mam/Silon 

g/ Nagadong Clans 

10 10.14 

18 Rangam Tayang/Saga Clans 16 21.65 

0.68 53040.00 Kamlang RF 

790920.00 

1688700.00 

Kamlang RF 

Kamlang RF 

19 Haloliang Tayang Clan 2 14.77 1152060.00 Kamlang RF 

20 Tangam Tayang Clan 10 6.06 472680.00 Kamlang RF 

21 Netoh Thalai clan 5 35.48 

22 Langmeh Thalai clan 8 34.21 

23 Langjong 

B. Surface Structures 

S.No Village 

5534880.00 

2668380.00 

USF 

Kamlang RF 

Thalai Clan 4 28.87 2251860.00 Kamlang RF 

Thalai Clan 16.74 1305720.00 Kamlang RF 

Sub Total (A) 204 652.18 8,83,68,380 

Project 

component/Purp 

ose 

1 Pram L/B Lohit dam axis 

No. of 

Families/Househ 

olds 

Land belongs to 

PAF of families 

already counted 


Area 

(ha) 

Total 

Property 

Value (Rs) 

4.32 336960 

Land Use 

Reserved 

Forest 

10-16


S.No Village 

Project 


ose 

2 Tayuliang R/B Lohit dam axis 

3 Tayuliang 

4 Kanday 

Power House 

Complex Area 

including Tail Race 

tunnel & Pressure 

shaft 

Muck Dumping 

Area/Stack Yard 

5 Tayuliang Magazine Area 

6 Tayuliang 

7 Tayuliang 

Construction Facilities 

Crusher Plant & 

batching plant -1 

Crusher Plant & 

batching plant -2 

and 3 

No. of 


olds 

for in Wakro circle 




for in Tezu circle 





Area 

(ha) 

Total 

Property 

Value (Rs) 

12.13 1892280 

21.59 3368040 

Kanday 150 23400000 













5 780000 

5 780000 

6.24 973440 

8 Kanday Equipment Kanday 25.47 3973320 

9 Kanday Workshop Kanday 5 780000 

10 Kanday Steel yard Kanday 13 2028000 


CISMHE 

Land Use 

Community 

Forest Land 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Community 

Forest Land 

Community 

Forest Land 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Kanday 

Community 

10-17


S.No Village 

Project 


ose 

No. of 


olds 

Area 

(ha) 

Total 

Property 

Value (Rs) 

11 Kanday Fabrication yard Kanday 13 2028000 

12 Kanday Labour Camp Kanday 36 5616000 

13 Kanday Office setup Kanday 3 468000 

14 Kanday Office Colony Kanday 5 780000 

15 Kanday 

16 Tayuliang 

Permanent Colony 

Area 

Quarry Area above 

Submergence 

(excluding 36.47 

ha of quarry area 

in submergence) 

17 Tayuliang DT outlet Area 

Sub Total 

(B) 

C. Approach Roads 

1 Pram Left Bank Road (1) 

2 Pram Left Bank Road (2) 

Kanday 60 9360000 
















23.53 3670680 

6.73 524940 

395.01 60759660 

5 780000 

3 468000 

CISMHE 

Land Use 

Forest Land 

Kanday 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Kanday 

Community 

Forest Land 

Community 

Forest Land 

Dining 

Reserve 

Forest 

Community 

Forest Land 

Community 

Forest Land 

10-18


S.No Village 

3 Tayuliang 

4 Tayuliang 

5 

Taseliang 

Chaigaidheli 

ang 

Chadheliang 

Dingliang 

Sub Total 

(C) 

D. Underground 

1 Pram 

2 Tayuliang 

3 Tayuliang 

4 

Project 


ose 

R/B DT intake and 

quarry area road 

R/B DT outlet and 

diversion road 

Tidding diversion 

Road 

Diversion Tunnel 

L/B Lohit 


R/B Lohit 


R/B Lohit 

Pressure shaft 

already included in 

PH area (3.8 ha) 

No. of 


olds 



























Area 

(ha) 

Total 

Property 

Value (Rs) 

9.84 1535040 

2 156000 

12.4 2170000 

32.24 5109040 

0.84 131040 

2.67 208260 

4.11 641160 

Sub Total 7.62 980460 


CISMHE 

Land Use 

Community 

Forest Land 

Dining 

Reserved 

Forest 

Community 

Jhum Land 

Community 

Forest 

Land 

Dining 

Reserve 

Forest 

Community 

Forest 

Land 

10-19


S.No Village 

(D) 

Grand Total 

(A+B+C+D) 

Project 


ose 

No. of 


olds 

204 

Area 

(ha) 

1087.0 

5 

Total 

Property 

Value (Rs) 

15,52,17,540 

CISMHE 

Land Use 

Note : 

1. The property value above is calculated based on land compensation only. In 

case of USF/Community Forest land 25 % NPV and, in case of Community 

Jhum Land/Community agricultural Land, 30 % Solatium of land value and 

Cost of Crops (Rs 1,00,000 per ha in Hilly area - or Rs 1,20,000 per ha in 

Plain area) would be paid additionally. 

2. The land requirement is assessed based on the latest project features and 

Project Layout finalized by CEA during DPR appraisal and same land details 

have been submitted in final forest application for diversion of forest land. The 

legal status is shown as per the findings of Property Survey carried out so far 

during March 2008 to October 2008. However the actual location of 

component wise land requirement and ownership may slightly change as per 

the assessment of State Land Acquisition officer (SLAO) and as per the 

provision of Forest Conservation Act–1980 for which application has been 

submitted to the State Government. However the total land requirement i.e. 

1589.97 ha will remain the same. The cost arrived is based on the legal 

status as per the property survey, however, the final actual compensation 

shall be paid as per the revised property survey by the State Government). 

10.4.1.2 Compensation for trees: 

Compensation for trees standing on the acquired agricultural land would be 

payable to the entitled land owner families as per the valuation done during the 

property survey. The itemized value of different trees is as detailed below: 


10-20


Table 10.4: Compensation for standing trees on the land to be acquired in Demwe Lower 

HEP (Property Survey, 2008) 

S No Description of Properties Quantity Per Asset Value in Rs Total Cost 

1 Orange Tree 358 1500 537000 

2 Banana Grove Tree 1655 50 82750 

3 Mango Tree 2 1200 2400 

4 Guava Tree 1 800 800 

5 Orange nursery plant 200 10 2000 

6 Jati Bamboo 6900 25 172500 

TOTAL 9116 7,97,450 

10.5 PROVISIONS MADE FOR SOCIO-ECONOMIC UPLIFTMENT OF PROJECT 

AFFECTED PEOPLE AND LOCAL POPULATION 

10.5.1 Brief Socio-Economic Profile 

A detailed socio-economic profile of the project and surrounding areas is given in 

Socio Economic chapter of the EIA report. In order to understand the social and 

cultural issues, loss of livelihood and infrastructure development in the 

surroundings that are directly related to the Rehabilitation and Resettlement 

Plan, a brief discussion on socio-economic profile is given below. 

10.5.1.1 Project Area 

The proposed Demwe Lower H.E. project is located in the Hayuliang, Wakro and 

Tezu circles of Hayuliang, Namsai and Tezu sub-divisions in Lohit and Anjaw 

districts. Total population of Hayuliang circle is 5202 belong to 1139 households. 

Sex ratio is 675 considerably lower than neighboring circles. The average literacy 

rate is 57% with considerably higher in male population (68.7%). Tezu circle 

covers an area of 1280 sq. km. Total population of Tezu circle is 31,304 with sex 

ratio of 814. About 48% of the total population of Tezu circle is urban. Total 

literacy rate in Tezu circle is 70.6%, which is considerably high as compared to 

the state and district averages. Scheduled cast (SC) population accounts for 

0.69% while scheduled tribe (ST) population is 24.4%. Wakro circle covers an 

area of 1665 sq. km. Total population of Wakro is 6809 with 100% rural. Sex ratio 


10-21 

CISMHE


in Wakro is 863. Average literacy rate in Wakro circle is 46.4% with considerably 

low in females. The literacy rate is lower than state and district averages. 

Scheduled caste population accounts for 0.71% while scheduled tribes constitute 

about 47% of the total population. Major tribe in the area is Mishmi. 

10.5.1.2 Influence Zone 

A total of 41 villages are located in the 10 km radius of proposed project - 

Demwe Lower H.E. project, of which 21 come under the jurisdiction of Hayuliang 

circle, 7 under the Tezu circle and remaining 13 are under the Wakro circle. Total 

population of vicinity villages is 4293, belong to 973 households. Population 

within the age class 0-6 year accounts for 20.1%. Average sex ratio is 750. 

Scheduled caste population residing only in Demwe village only, accounts for 

1.3% of the total population. Scheduled tribe population is 38.9% of the total 

population; they dominate native villages like Wakro, Gundri, Mawai. The 

average literacy rate is 44.58%, which is considerably higher in male population 

(55.53%). Primary schools are located in Demwe, Wakro, Mawai and Phukri 

villages. Only Wakro among the vicinity villages has facilities of high school and 

secondary school level education. About 53% of the total population is engaged 

in various types of works like cultivation, agriculture, households industry etc. Of 

the total workers, nearly 88% are main workers, dominated by males. Citrus is 

the main horticultural crop in the area. Other crops include ginger, maize and 

pulses. The native tribes are engaged mainly in the citrus cultivation (about 58% 

of main workers) while migrant people are employed in the road construction, 

household industry etc. 

10.5.1.3 Project Affected Families 

Along with the Property Survey, a detailed Socio Economic Survey was 

conducted among the PAF’s. During the survey, it has been observed that most 

of the families belonging to various communities have migrated to lower reaches 

in and around the Wakro, Tezu and Hayuliang circles doing agriculture, 

government jobs and small business etc, but still vests right over the community 

land. None of the families are residing in the area to be acquired for the project, 


10-22 

CISMHE


hence no homestead is getting affected due to submergence of the Demwe 

Lower HE Project, however a total of 204 families having tribal rights on the land 

likely to be affected partially due to the various components like dam, colony, 

quarries, tunnels etc. of Demwe Lower H.E. project on account of their 

jhum/agriculture land under the community name. These families belong to 23 

villages/hamlets spread over Wakro, Tezu and Hayuliang circles. Based on the 

property survey details, villagers claim a total land 1087.05 ha under various 

community names. Since there is no individual land holding, the affected 

community lands, owned by the different villages, were taken into consideration 

in formulating the R & R grants. Each family having right of exploitation of a 

particular community land was considered as project affected family (PAF). 

Total population of the project affected families is 1349 belonging to 204 

households. All the project affected persons belong to Scheduled tribes category, 

and are of mostly Tayang and Thalai communities of Miju and Digaru Mishmis. 

Average literacy rate among the projected affected families is 63.01% with 

significantly high in male population. Total workers population in the affected 

families is 30.9%, of which 74.5% are employed in the cultivation and agricultural 

practices. Citrus is the main horticultural cash crop of affected families while 

millets, maize, rice etc. are main agricultural crops. People practice Jhum and dry 

cultivation. About 19.6% of the total workers are employed in the government 

services. Only 4.7% of the total workers are engaged in the small scale business. 

Livestock of affected families comprises of cows, mithuns, ox, horses, pigs, goats 

and other animals. Pigs, mithuns and cows comprise the major share of livestock 

population. Cows are reared mainly as source of milk. Mithun is a semi 

domesticated animal, owned by tribes. 

The community land in the upper reaches have no basic infrastructural facilities, 

these villagers who have shifted to other places will occasionally visit these 

places for the agricultural purposes. The present settled villages are connected 

by the National Highway 52 and pucca roads. The houses of Mishmis are 


10-23 

CISMHE


kaccha, made up of bamboo, cane, leaves of straw and wood, raised about two 

feet above the ground on the wooden posts. Most of the houses avail the 

electricity and tap water facilities. Wood is the main fuel among the affected 

families; however, about 40% families are consumers of cooking gas whereas 

72% also use kerosene as fuel. More than 45% families have access to the 

television, which is the main medium of entertainment. About 12% families are 

connected with telecommunication. Only 4% use fridge in their homes. About 

37% families have their own vehicles; most of them are two wheelers. Only 6% of 

the total population of affected families is employed in the government jobs. 

About 13% families have been categorized as BPL (below poverty line). In line 

with the R&R interventions recommended in various policies, following best 

suited measures are suggested for each of the components in the following 

paragraphs. 

10.5.2 Schedule tribe family grant as per NRRP, 2007 

Each Scheduled Tribe affected family shall get an additional one-time financial 

assistance equivalent to five hundred days minimum agricultural wages for loss 

of customary rights or usages of forest produce or Rs. 50,000/-. 

Livelihood Grant 

As per the provisions of Arunachal Government R&R policy, in case of a project 

involving land acquisition on behalf of a requiring body each of the affected 

families who have been rendered landless after land acquisition and have not 

been provided agriculture land or employment shall be entitled to a livelihood 

grant equivalent to 1000 days minimum agricultural labour wage @ Rs. 100/day. 

In the present case, though no such case is reported; however, to take care of 

any such need, a lumpsum provision of Rs 2,00,00,000/- has been kept for this 

purpose. 

BPL Family grant as per NRRP, 2007 

In addition to their rightful compensation of land and other standing property, an 

amount of Rs. 50,000 will be granted to the family whose land has been acquired 


10-24 

CISMHE


and belongs to BPL category. The information of BPL status would be provided 

by the Head of the BPL family along with general application form. With all 

necessary certificates required for the landless/houseless/eligible family grant, a 

separate certificate of BPL status and caste certificate from the officer not below 

the rank of SDM/DM/DC will be submitted by the head of the BPL family to claim 

this grant. A provision of Rs 102,00,000/- has been kept for this BPL grant. 

10.5.3 Vulnerable person family grant 

Pension of Rs. 500/- per month for lifetime to vulnerable affected person such as 

widows, unmarried adult women, all those above 50 years of age without family 

support. 

10.5.4 There will be an option of acquiring entire agriculture land, if 75% of land 

holdings are required for acquisition. 

10.5.5 The tribal families residing in the project affected areas having fishing rights in 

the river/reservoir. 

10.5.6 Free electricity As per Arunachal Policy 

The project developers will provide to each of the project affected families the 

benefit of 100 units of electricity per month free of charge for a period of 10 years 

from the date of commissioning of a hydro-electric project. In case of the affected 

family not consuming 100 units of electricity, the cost of balance unused units 

shall be made available to the family in cash. 

10.5.7 The project affected families, who were in possession of forest lands prior to 25 th 

October, 1980 shall get all the benefits of Relief and Rehabilitation as under the 

policy. The Relief package for the affected families has been shown in Table 

10.5. 


10-25 

CISMHE


Table 10.5: R&R package for the project affected families of proposed Demwe Lower 

H.E. project 

Particulars nos 

Amount (in Rs.) 

A) Total No. of project affected Families 204 

B) Total Cost of Land Value 15,52,17,540 

C) Cost of Trees 7,97,450 

D) Scheduled Tribe family grant 

Total Number 204 

@ Rs. 50,000 1,02,00,000 

E) Vulnerable Person Grant 

Pension for vulnerable persons 

(average life 50 years per person) 

Total Number 60 

@ Rs. 500 per month for lifetime 1,80,00,000 

F) Free Electricity grant 

100 units per month for PAF’s for 10 year 

No. of families 204 

@Rs. 5.00/unit (lump sum rate) 1,22,40,000 

H) Livelihood grant 2042,00,00,000 

I) BPL Family grant 204 102,00,000 

Grand Total (B+C+D+E+F) 22,66,54,990 

10.5.8 Application for Grant and Grant Distribution 

The Commissioner/ District magistrate or his/her representative not below the 

rank of ADM/ SDM from Lohit and Anjaw district as the case may be, will be the 

sanctioning authority for the rehabilitation grant, which shall be provided by the 

project authorities. Affected family/ person will apply on a general prescribed 

format, which will furnish the information of the village; details of his/her land 

acquired, family status, etc. The form will be submitted to the project office and 

evaluated by Land Acquisition Officer and General Manager of the Requiring 

Body (ADPP Ltd). After receiving the list of PAF’s by District Magistrate, the 

options will be invited from head of affected family on stamp paper and this will 


10-26 

CISMHE


be rooted through SDM concerned. District Magistrate shall be the final authority 

to sort out the disputes between affected families and the project authorities. All 

stamp duty and fees of registration shall be born by the project developers. After 

submitting all necessary document R&R cell would disburse the compensatory 

amount to the affected person. If there is any dispute between affected person 

and the project, Commissioner / DM can interfere to sort out the disputes. 

Alternatively, R&R cell of ADPP Ltd can execute the procedure of grant 

distribution by involving a reputed NGO and civil society groups. 

10.6 LOCAL AREA DEVELOPMENT PROGRAMME 

10.6.1 Amenities and Facilities available in the Influence Zone Area 

Information pertaining to access to various amenities and facilities by the 

residents in the Influence Zone area was gathered from the Census data, 2001 

and during the primary Survey. The details of various amenities and facilities 

available in the study area are compiled in Table 10.6. 

10.6.1.1 Educational facilities 

Access to educational facilities is quite poor in the influence zone. Primary 

School is available in 18 out of the 41 study area villages, while middle and high 

schools are available in 5 and 2 villages respectively. The children have to travel 

to longer distances to pursue higher education, only in about 4 of the 41 villages 

children have to travel about 0-5 km to attend school. 

10.6.1.2 Medical facilities 

Primary Health Center is available in only 4 (Wakro Village, Kharangliang, 

Mahikong and Dingliang) out of the 41 villages. Primary Health Sub-center is 

available in only 8 out of the 41 villages. Community Health Workers are 

observed in 9 out of the 41 villages. CWC is observed in 2 out of the 41 villages. 

Besides, for about 10 and 5 villages, the nearest health care center is located 

less than 5 km and between 5 and 10 km respectively. While for the remaining 8 

villages, the nearest medical facility is located at a distance of more than 10 km. 


10-27 

CISMHE


10.6.1.3 Potable drinking water 

Water for drinking purposes is available in the SAVs through taps and springs. 

About 28 and 7 of the villages have access to Tap water and spring water 

respectively for meeting their domestic water requirements. The residents of the 

remaining study area villages (3) use water from springs as well as tap. 

10.6.1.4 Electricity 

In the study area about 20 villages have access to electricity supply to meet only 

the domestic lighting and about 16 villages have access to electricity supply for 

all purposes. The remaining villages (2 in Nos.) are not electrified and no data 

available for 3 villages. 

10.6.1.5 Post and Telegraph 

Post office is located and available only in 2 villages within the influence zone. 

Phone facility, on the other hand, is available in 1 villages. In about 12 villages 

each, post and telegraph facility is available at a distance less than 5 km and 8 

villages between 5 and 10 km respectively. While in the remaining villages, the 

villagers have to travel more than 10 km to access a post office. 

10.6.1.6 Local Markets 

As per the available data, none of the villages have access to a market place on 

a daily basis, and the residents have to travel varying distances to the nearest 

market place. In only 6 villages, the residents have to travel a distance of less 

than 5 km to get to reach the nearest market, while in the remaining villages the 

residents travel more than 10 km to reach the nearest market. 

10.6.1.7 Transport and Communication 

About 15 villages in the influence zone are connected with a Pucca road, while 

18 of the villages have connectivity through Kutcha road. The remaining 8 

villages do not have any road connectivity and they are accessible only through 

foot-path. About 12 influence zone villages have a bus stop. Other villages in the 


10-28 

CISMHE


influence zone do not have access to transportation facilities and the nearest 

bust stop is located at varying distances from less than 5 km to more than 10 km. 

Hayuliang, Tezu, Wakro and Namsai are the nearest towns for the villages. 

In view of the above, since many villages are not even having basic 

amenities like medical facilities, communication facilities, adequate 

provisions have been proposed under the LADP for the economic 

upliftment of the affected persons as well the study area villagers. 


10-29 

CISMHE


Environnemental Management Plan – Rehabilitation & Resettlement Plan 10-30 

CISMHE 

Table 10.6: Status of basic amenities in the villages of Influence Zone of Demwe Lower HEP. 

Village Name Education Medical 

Hayuliang Circle 

Drinking 

Water 

Post & 

Telegraph 

Approach 

Market Communication 

Road 

Nearest 

Kibom Nil PHS, CHW T, S PO -(10+ KM) BS PR Hayuliang (52 km) EA 

Dingliang Nil PHC, CWC T PO, Phone -(10+ KM) BS PR Hayuliang (30 km) EA 

Rahagam Nil -(-5 KM) T -(-5 KM) -(10+ KM) BS PR Hayuliang (22 km) EA 

Mologam DNA DNA DNA DNA DNA DNA DNA DNA DNA 

Machima M,P PHS, CHW (2) T, S -(10+ KM) -(10+ KM) -(-5 KM) KR Hayuliang (26 km) ED 

Lamaliang Nil -(-5 KM) S -(-5 KM) -(10+ KM) -(-5 KM) FP Hayuliang (70 km) EA 

Tadumna Nil -(-5 KM) S -(-5 KM) -(10+ KM) -(-5 KM) FP Hayuliang (75 km) - 

Mahikong Nil PHC, CWC T PO -(10+ KM) BS PR Hayuliang (18 KM) EA 

Zapaliang Nil -(-5 KM) T -(-5 KM) -(10+ KM) BS PaR Hayuliang (13 KM) ED 

Chiphugam Nil PHS T -(10+ KM) -(10+ KM) -(10+ KM) FP Hayuliang (40 KM) - 

Takaliang Nil -(5-10 KM) T -(5-10 KM) -(10+ KM) -(10+ KM) KR Hayuliang (35 KM) ED 

Naraliang P PHS T -(10+ KM) -(10+ KM) -(10+ KM) KR Hayuliang (40 KM) ED 

Kharangliang Nil PHS, PHC T PO -(10+ KM) BS KR Hayuliang (16 KM) EA 

Hayuliang H CHW T PO -(10+ KM) BS KR Hayuliang (12 KM) EA 

Tawaikunung Nil -(-5 KM) T, S -(-5 KM) -(-5 KM) BS PR Hayuliang (3 KM) ED 

Chillang Nil -(-5 KM) T -(-5 KM) -(-5 KM) -(-5 KM) FP Hayuliang (4 KM) EA 

Mompani Nil CHW T -(5-10 KM) -(10+ KM) -(-5 KM) KR Hayuliang (12 KM) EA 

Mahikong Nil PHS, CHW T PO -(10+ KM) -(10+ KM) KR Hayuliang (15 KM) EA 

Paya Nil -(-5 KM) T -(-5 KM) -(10+ KM) -(10+ KM) KR Hayuliang (20 KM) EA 

Chingraliang Nil PHS, CHW T -(5-10 KM) -(10+ KM) -(10+ KM) KR Hayuliang (30 KM) EA 

Town 

Power 

Supply


Village Name Education Medical 

Drinking 

Water 

Post & 

Telegraph 


CISMHE 

Approach 

Market Communication 

Road 

Nearest 

Chirang P -(-5 KM) S -(-5 KM) -(-5 KM) -(-5 KM) FP Hayuliang (5 KM) ED 

Tezu Circle EA 

Soiliang P1,M2 -(10+ KM) S -(10+ KM) -(10+ KM) -(5-10 KM) KR TEZU (65KM) ED 

10th Nallah P3 -(10+ KM) S -(10+ KM) -(10+ KM) -(5-10 KM) PR TEZU (25KM) ED 

Lalpani Rd. side P1 -(10+ KM) S -(10+ KM) -(10+ KM) -(5-10 KM) PR TEZU (45KM) ED 

Demwe S1, P1, -(10+ KM) T -(10+ KM) -(10+ KM) -(5-10 KM) PR TEZU (14KM) EA 

Tinali Brahma Kund Nil -(10+ KM) T -(10+ KM) -(10+ KM) BS PR TEZU (30KM) ED 

Salamgam Nil -(10+ KM) T -(10+ KM) -(10+ KM) -(5-10 KM) PR TEZU (60KM) ED 

Tidding Nil -(10+ KM) S -(10+ KM) -(10+ KM) -(5-10 KM) PR TEZU (70KM) ED 

Wakro Circle 

Fango(Famgo) No Settlement Due to Migration 

Lakao No Settlement Due to Migration 

Parsuram Kund P -(10+Km) T -(10+Km) (10+Km) BS PR Wakro (16KM) ED 

Mawai - I P -(5-10Km) T -(5-10Km) -(5-10Km) -(5-10Km) KR Wakro (8KM) ED 

Mawai – II Nil -(5-10Km) T -(5-10Km) -(5-10Km) -(5-10Km) KR Wakro (8KM) ED 

New Phukari Nil -(5-10Km) T -(5-10Km) -(5-10Km) -(5-10Km) KR Wakro (7KM) ED 

Phukari(Old) P, M -(5-10Km) T -(5-10Km) -(5-10Km) -(5-10Km) KR Wakro (7KM) ED 

Kanjang P -(-5Km) T -(-5Km) -(-5Km) -(-5Km) KR Wakro (3KM) ED 

Gundri Nil -(-5Km) T -(-5Km) (-5Km) -(-5Km) KR Wakro (3KM) ED 

Wakro Village P,M PHC T -(-5Km) (-5Km) BS PR Wakro (1Km) EA 

Kamlang Nagar P PHS T -(-5Km) -(5-10Km) -(-5Km) PR Wakro (9KM) EA 

Namgo P PHS T -(5-10Km) -(5-10Km) (5-10Km) KR Namsai(60 Km) DNA 

Manyuliang P Nil T -(-5Km) -(-5Km) BS KR Namsai (46Km) ED 

Town 

Power 

Supply 

10-31


10.7 ENVISAGED BENEFITS 

In addition to the relief and rehabilitation package for the affected families, the 

project authorities will undertake a plan of infrastructural development in the area 

which would result in better quality of life for the entire human population of the 

area. Several such facilities would be created for the benefit and use of general 

public. A detailed account of these proposed development activities is presented 

based on envisaged impacts of the project. 

10.7.1 Economic Development 

The proposed Demwe Lower is a large hydro-electric project, which would 

require a large number of workers, officers and other staff. As a result of 

increased population and with more surplus income at their command, together 

with enhanced requirements of food grains, vegetables, milk, clothing and other 

grocery items, there would be a sharp increase in the business activity and 

turnover of existing businessmen. This would also lead to establishment of new 

markets and growth of local economy. In addition to the prospering business 

establishments, there would be requirement of some ancillary local level industry 

for providing hardware to the project activities, which again would result in 

upliftment of local economy and better quality of life. 

10.7.2 Employment Opportunities 

The proposed Resettlement & Rehabilitation Policy (2008) of Arunachal Pradesh 

Government has recommended a fair participation of local people in the jobs in 

the project. The project authorities directly as well as through their contractors 

would ensure that local population gets good number of jobs. The jobs, however, 

would be determined by the qualifications and experience of the persons wanting 

to be employed. It will also provide an opportunity to many unskilled youth to 

become skilled. By gaining technical knowledge and experience, their chances of 

gainful employment will be greatly enhanced. Enhancing the local people’s skills 

and opportunities for employment the project would result in uplifting the 

standard of living and the existing quality of life of the local inhabitants. This 

would go a long way in making the area economically self-sustaining. 


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Besides generating local employment for the skilled and un-skilled labour, the 

project would also provide an opportunity for the local people to compete for 

various contracts related to project works, depending on their economic status. 

The participation in this process would, however, be guided by the usual process 

of tendering. Project Developer would ensure as far as possible, to engage local 

labourer in various skilled/non-skilled jobs depending on a candidate’s 

qualifications and experience. There would also be sufficient opportunities for 

indirect income generating activities, which include provision of services to 

contractors, opening of small and medium sized market place/ shops, etc. Project 

authorities will provide various training and will run income generating schemes 

for local youth. These developments would be helpful in self employment of the 

local residents. 

The company setting up hydro power projects shall give the preference to local 

tribal people in following categories of posts, subject to the incumbents fulfilling 

the job requirements as per the criteria given below; 

i) Managerial/Professional posts 25% 

ii) Clerical posts 50% 

iii) Skilled jobs 25% 

iv) Unskilled jobs 75% 

10.7.3 Educational Facilities 

The area is poor in the education facilities. The project authorities would 

establish educational institutions in the area for the children/wards of their project 

employees. These institutions shall also be open to the children of the local 

inhabitants. At some places, grants would be provided for the maintenance and 

upgradation of existing educational institutions which would be a great benefit for 

the local residents. 

10.7.4 Health Related Facilities 

The project authorities would establish healthcare facilities in terms of healthcare 

centers at a few affected villages and for their employees. These centers shall 


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extend services to the local people. Project authorities would provide mobile vans 

for emergency services in the area. 

10.7.5 Sports Facilities 

The project authorities would construct and establish club/playgrounds for the 

project employees/ sports competitions and sports meets would be organized 

between the local players and project employees which would ensure the local 

participation. This will also provide them necessary facilities for excelling in 

sports of their choice. These facilities would go a long way in honing and 

nurturing the local talent in the field of sports and competitive games. 

10.7.6 Recreational Facility 

Provision of green belt in the periphery of the reservoir, landscaping and 

establishment of botanic gardens/butterfly parks will enhance the scenic beauty 

and tourist spots of the area and attract the local and outside tourists. 

10.8 PROPOSED FINANCIAL OUTLAY FOR LOCAL AREA DEVELOPMENT PLAN 

The influence zone of the Demwe Lower HEP is considered an abode for Mishmi 

tribes, having uniqueness in culture and customs. The area is sparsely 

populated. The Mishmis have traditional right on the forest produce and practice 

shifting cultivation and regular hunting. The forest is, therefore, under heavy 

anthropogenic pressure. The proposed infrastructure development has been 

suggested keeping in view the cultural complexity and sensitivity of the area. The 

developmental activities and the involvement of tribes might divert their focus 

from the exploitation of forest. The required infrastructural facilities are described 

under the following headings. 

10.8.1 Training Program 

Following the clause 7.13.2 of NRRP, the affected persons shall be offered the 

necessary training facilities for development of entrepreneurship, technical and 

professional skills for self-employment. Training on the food processing, 

mushroom cultivation, computer courses, organic farming, apiculture, 


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vermiculture, eco-tourism, poultry farming, dairy farming, knitting, sewing etc. 

could open new areas of self employment in the region. Requiring body would 

invite trainees among the affected families for the training on various courses. 

The requiring body would select 60 trainees every year for the period of 5 years 

(Rs 6000/month). If the applicants are not available among the affected families 

the training programme can be extended to the affected villages and/or villages 

located in the 10 km radius. The applicants can obtain application form at no cost 

from the office of requiring body (ADPP Ltd) (Annexure-I). Applicant would 

submit application form along with certificate of land acquired from the LAO 

(Land Acquisition Officer) of Requiring Body, income certificate from DC/SDM/, 

certificates of educational qualification, caste certificate issued by an officer not 

below the rank of executive magistrate and verification certificate of the 

concerned Gram Pradhan. The scheme is only a welfare measure for the PAF’s 

and does not confer any right on the PAF’s for financial assistance. If the 

requiring body is not able to develop all infrastructural facilities for all the training 

programmes, it may consult concerned department of the state to facilitate 

training to the applicants. The requiring body would bear all expenditure including 

accommodation, travel etc. of the trainees and charges of the concerned 

department. Total financial out lay for the training programme has been kept as 

Rs. 216.00 lakhs. 

10.8.2 Merit Scholarship Scheme 

As per clause 7.13.1(c) of NPRR, requiring body shall offer scholarships and 

other skill development opportunities to the eligible persons from the affected 

families as per the criteria fixed by the appropriate Government. To improve and 

encourage the literacy and educational standards in the project affected area and 

to create a pool of potential candidates, Requiring Body (ADPP Ltd) proposes to 

introduce a Merit Scholarship Scheme for the wards of the Project Affected 

Families. If the wards from the affected families are not eligible and/or available, 

then Merit Scholarship Scheme would be extended to the wards of the affected 

villages or vicinity villages. The wards should be studying in school, college or 

any other educational institute recognized by State or Central Government or a 


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reputed private institution. The students should not be receiving any other 

scholarship of State and Central government. A total of 50 students every year 

will be selected for the scholarship on merit basis. The scholarship would be 

divided on the basis of standards and disciplines, viz. Senior secondary school 

(15 students), Vocational training (15 students), Diploma (10 students) and 

Degree in Science, Engineering, Medical etc. (10 students). The scholarship will 

last for the tenure of course. The scholarship @ Rs.2000/-, Rs.5000/-, Rs.7000/and 

Rs.9000/- per month would be provided to the students of secondary school, 

vocational training, diploma and degree, respectively. The project authorities 

propose to run this scheme at least for 5 successive years. After completion of 

the scheme, Requiring Body reserves the right to restart or terminate this 

scheme. 

The eligible students may apply for the grant of scholarship as per the format given 

at Annexure-II. The amount of the scholarship shall be released on a half-yearly 

basis. The submission of application for scholarship shall not guarantee the grant 

of scholarship. Requiring body management shall reserve the right to accept or 

reject any or all application without assigning any reasons. Requiring Body also 

reserves the right to reduce/ increase the number of beneficiaries or change the 

number of beneficiaries in different standards depending upon availability of the 

students. The eligible candidate shall apply on the prescribed form printed by 

Requiring Body. Duly completed application form should be submitted along with 

attested copies of marks sheets of previous annual examinations, certificates of 

land/ house acquisition from LAO and two passport size photographs attested by 

the principal/head of the institute. Total budget for the Merit scholarship including 

increment has been kept as Rs. 159.00 lakhs. 

10.8.3 Marriage grant 

Requiring body would provide an amount of Rs. 10,000 to the daughter of 

affected family of BPL category as a marriage grant. The provision is kept for a 

daughter in a family, but if affected family person would apply second time for 

marriage grant, requiring body can consider it. The grant would be given 


10-36 

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preferably to the affected families; however, project authorities may extend it to 

the families of the influence zone. A lumpsum budget for the purpose has been 

kept as Rs. 40.80 lakhs. 

. 

10.8.4 Income Generation Scheme 

As discussed earlier, requiring body would run various training programmes for 

the youth of the project affected area. Food processing, vermiculture and 

mushroom cultivation are given special attention due to their easily availability in 

the region. After completion of training, project authorities may provide financial 

assistance to the trained project affected person to enable him/her to generate 

his own source of income. In addition to the different vocations, this scheme will 

be extended to small scale business, apiculture, sewing knitting, etc. The 

preferences will be given to those belonging to Scheduled Caste, Scheduled 

Tribe and vulnerable groups. Any family whose member has been provided 

employment in the company will not be considered for this scheme. The 

candidate would opt for any vocational training and would be paid 80% of the 

cost of the assets, procured for the vocation (up to a maximum of Rs. 50,000). 

The amount of the financial assistance would be paid by Requiring Body to 

supplier (s) of assets. The financial assistance would be a one time grant and the 

requiring body would not stand guarantee or surety for the loan amount arranged 

by the applicant. The maximum number of beneficiaries of the scheme will be 

about 20 for every year. 

The applicants are required to submit their application in the enclosed prescribed 

format (Annexure-III). It would be submitted along with certificate of land acquired 

from LAO (Land acquisition Officer) of Requiring Body, income certificate from 

DC/SDM/ certificates of educational qualification, caste certificate issued by an 

officer not below the rank of executive magistrate and verification certificate of 

concerned Gram Pradhan. The scheme is only a welfare measures for the PAF’s 

and does not confer any right on the PAF’s for financial assistance. The 

Requiring Body’s decision in implementation of the scheme will be final and the 

Requiring Body reserves the right to accept or reject any application. Total 


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budget for the Income generation Scheme including creation of basic 

infrastructure would be Rs. 250.00 lakhs. 

10.8.5 Education Facilities 

Due to the poor education and transport facilities, students from surrounding 

villages face serious problems. To strengthen the education facilities one senior 

secondary school or a high school are suggested. In addition, primary and middle 

schools would also be established. The project authorities in consultation with the 

State Education Department would decide the final location of schools at central 

places. The project authorities would provide all the infrastructure, salaries and 

maintenance grant for the schools for at least five years. Total budget for the 

proposed schools including buildings, salaries and maintenance would be Rs. 

16,60,00,000 (Rs. Sixteen crores and sixty lakhs only). The break up of the 

budget is given below: 

Components 

A.Salaries 

Amount (In Rs.) 

Primary Teacher (No. 8) (Basic pay Rs. 9840/-) 90,00,000 

Middle School teacher (No. 12) (Basic pay Rs. 11,170/-) 1,50,00,000 

High School teacher (No. 20) (Basic pay Rs. 11, 170 & Rs. 14,430/- ) 2,80,00,000 

Senior teachers (No. 12) Basic pay Rs. 14,430 & Rs. 16,290/- 2,10,00,000 

Sub total A 7,30,00,000 

B.School buildings 7,40,00,000 

C.Play grounds 40,00,000 

D.Maintenance grant 1,00,00,000 

E.Miscellaneous grant 50,00,000 

Total 16,60,00,000 

10.8.6 Health Related Facilities 

The details of establishing a Public health delivery system has been given in the 

Chapter 4 of EMP report with a financial outlay of Rs. 11,86,76,000/-. 


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10.8.7 Bus Stops/ Rain Shelters 

Surrounding villages are connected by the National Highway 52. Villages are 

sparsely located; there is dearth of link roads and traffic density is low. People 

traverse up to 5 km or more than 5 km distance on foot. There are no proper bus 

stops on the state highways and link roads. For the convenience of the residents, 

rain shelters and bus stops are suggested alongside footpaths and roads. Total 

cost estimates for 41 rain shelters @ Rs. 2,00,000 are Rs. 82,00,000 (Rs. Eighty 

two lakhs). 

10.8.8 Construction of Footpaths 

The villages are located on the hill slopes, many of which are not connected with 

the state highways and link roads. People use footpaths for their movement to 

and fro the villages. This at times leads to severe encumbrance to the residents, 

particularly during ill-health and sickness. The construction of new roads to these 

villages may not advisable because it may lead to degradation of the forest, 

therefore, construction of new pacca footpaths and repairs of the existing 

footpaths are suggested for the project affected villages. Construction of 

approximately 3 km long pacca footpath is proposed for each village/revenue 

village located in 10 km radius. The estimated cost (@ Rs. 200/m 3 ) of footpaths 

for 41 affected villages / revenue blocks would be Rs. 2,46,00,000 (Rs. Two 

crore, forty-six lakhs). 

10.8.9 Support Services for Agricultural and Horticultural Activities 

Citrus is the main crop in the region, especially in the villages of Wakro circle. 

Due to the lack of proper marketing facilities and markets, the citrus crop could 

not be a cash crop in this area. Our surveys reveal that establishment of a proper 

research centre for the improvement genetic viability and quality of citrus and 

training on the food processing can be helpful in the upliftment of the local 

economy. Regarding the support services to the affected area project authorities 

are suggested to establish a small research laboratory with staff, training centre 

with food processing unit and seed centre. The project authorities shall provide 

all the necessary infrastructures and support to such programmes for at least 5 


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years. The total financial outlay including infrastructure (Rs.50.00 lakhs), 

salaries/wages (Rs. 50.00 lakhs), contingency and miscellaneous 50.00 lakhs) 

for this programme would be Rs. 150,00,000 (Rs. One hundred fifty lakhs). 

10.8.10 Women Technology Park 

Mishmis women are considered as weaker section. They are considerably poor 

in getting education, health, malnutrition etc. The Women Technology Parks 

(WTP) in the area would create awareness, gender sensitivity and new 

technologies. The main objective of the WTP is to empower the women with the 

inputs of science and technology. Many grass root voluntary organizations have 

been running such types of parks in the country, which are sponsored by DST, 

Government of India. The project authorities are suggested to establish WTPs in 

the region at a cost of Rs 100,00,000 , which would provide trainings to the 

women on food processing, natural dyes extraction, fodder production 

technology, buffaloes rearing and milk production, cost effective water treatment, 

ergonomic assessment of hand tools etc. About 50 women from the affected 

villages shall be trained each year and shall be provided a allowance of Rs 

3000/month. The project authorities would provide trainers with the help of 

NGOs. Such types of support services would be provided for the 5 years. Total 

budget for the Women Technology Parks would be Rs. 1,90,00,000 (One 

hundered ninety lakhs). 

10.8.11 Protection of Cultural Heritage and Old Monuments 

Parasuram Kund in the project area is a monument of cultural importance. It is an 

evidence of spiritual contact between Arunachal Pradesh and rest of the country. 

Also, Mishmis themselves are unique in their customs and culture and they have 

their own temples and other places of worship. All these places are devoid of 

proper maintenance. Parasuram Kund and other places of worship need to 

maintained and repaired. In order to protect the ethnic values and cultural 

heritage, project authorities are suggested to renovate and restore all places of 

worship and festivals and develop a few cultural centres for Mishmi tribes. Total 

financial outlay for this head would be Rs. 5,00,00,000 (Rupees Five crore). 


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During the operation phase, the river water will be diverted through 4 diversion 

tunnels on right bank (each 1100 m long). In order to maintain the regular flow to 

Parasuram Kund a separate tunnel (850 m long and 6.0 m. diameter) will be 

constructed on the left bank by the project authorities. Also, project authority 

would install a 40 MW power unit at dam toe with respect to continuous minimum 

flow/ release of water in main channel. 

10.8.12 Assistance and Training to Fishermen 

Rehabilitation and Resettlement policy of Arunachal Pradesh Government has 

provision of fishing right in the reservoir for tribal families residing in the project 

affected areas. It would be new experience for the local residents to fish in the 

reservoir. The project developers propose to provide assistance and training to 

the local fishermen. The financial outlay for the training and assistance would be 

Rs. 150.00 lakhs (50.00 Training + 60.00 Boats & fishing accessories + 40 

Infrastructure). 

10.8.13 Communication Facilities 

Phone, internet and television access are most important ways of empowerment 

and development of communities. These are primary needs for the improvement 

of quality of life. The surrounding areas are lacking of these facilities. 

Communication facilities include ground based T.V. towers, ground and rooftop 

cell phone towers. The area is poor in post offices facilities. There is no post 

office in the 10 km radius of proposed dam site. In order to strengthen the 

communication facilities, at least three post offices are suggested in the 10 km 

radius. The project authority would bear the funds for the branch post offices for 

5 years. There is no provision of buildings for post offices. They will be hired as 

rent basis. After 5 years, these facilities would be handed over to the State 

Government. The affected villages shall be given preference; however, these 

facilities would be extended for those areas where these do not exist. The total 

budget for the communication facilities would be Rs. 6,00,00,000 (Six crores). 


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Ground based T.V tower (including maintenance grant) Rs. 2,00,00,000 

Ground and Rooftop cell phone towers (including maintenance grant) Rs. 

2,00,00,000 

Branch post office (No. 3) (including salaries/wages of post master, Rs. 

2,00,00,000 

Post man, Post runner) 

10.8.14 Community Welfare Centers 

Project authority will develop community welfare centers in those villages where 

this facility is not available. The preference will be given to project affected 

villages; however, Project authority can extend this facility to other villages in the 

vicinity. At least 10 villages are proposed (affected and surrounding villages) for 

this facility. All community welfare centres shall be provided with basic 

infrastructures. Total financial outlay under this head would be Rs. 4,50,00,000 

(Four crores fifty lakhs). 

10.8.15 Transportation Facilities 

Transport services in the region depend mainly on the state transport and private 

light vehicles, which are very sparse. The scanty transport facilities can be 

attributed to the sparse population, however, people suffer due to the poor 

transport facilities. The project authorities are suggested to provide transport 

services on the important routes like Tezu to Hayuliang, Hayuliang to Wakro, 

Wakro to Namsai. The project authorities shall provide basic infrastructure while 

people would pay as per norms of state government. The scheme would last for 

5 years. Total cost estimated for the infrastructure (buses) is Rs. 3,50,00,000 

(Three crores and fifty lakhs). 

10.8.16 Recreation Facilities 

Project authority would develop the recreation facilities and aesthetic value, viz. 

development of parks and view points alongside the road, near colony area, in a 

few villages etc. The financial outlay for the recreation facilities would be Rs. 

2,50,00,000 (Two crore fifty lakhs). 


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10.8.17 Public Library 

Public library can play an important role in the awareness of local people and can 

encourage the literacy in the area. Four libraries are proposed in the region 

located at Wakro, Parsuram Kund, Demwe and Pukhri. Ministry of Education of 

Arunachal Pradesh would be final authority to decide the location of proposed 

libraries. Total financial outlay for the libraries would be Rs. 1,50,00,000 (One 

crore fifty lakhs) 

10.8.18 Crafts and Skill Upgradation 

The industrial training is an important means for the development of effective 

work habits and method of work. The development of infrastructure and training 

are proposed to preserve and revitalize the traditional indigenous handicrafts, 

handlooms and sericulture products. The project authorities are suggested to 

allocate Rs. 2,60,00,000 (Two crore and Sixty lakhs) for the two handlooms units 

and two training centre in the region. Ministry of Agriculture of State would be the 

implementing agency. 

10.8.19 Market complex 

A market complex would be established near the working site to fulfill the daily 

needs of migrant laborers, local people and technical staff. The shops shall be 

distributed to the local inhabitants on the minimal rent basis. The project affected 

persons shall be given the preference. In case of non availability of project 

affected persons, it can be extended for the people of vicinity villages. Total 

financial outlay for the market complex would be Rs. 4,00,00,000 (Four crore). 

10.8.20 Water supply system 

Many villages within 10 km radius have tap water supply system while others are 

dependant on the spring water. However, potable water is untreated and prone to 

the water born diseases. There is provision of water supply system for those 

villages, where it does not exist. Also, project authorities would establish water 

treatment systems in the region. Total budget for the water supply would be Rs. 

5,00,00, 000 (Five crores). 


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10.8.21 Miscellaneous activities 

Miscellaneous activities include first aid facilities at labour camp, cretch for the 

infants of labourers, sanitation facilities, buses for labourers’ transport, 

establishment of graveyard and crematorium in the region. The total financial 

budget for the miscellaneous activities would be Rs. 6,00,00,000 (Six crores). 

It is important to mention here that the budgetary provisions under various heads 

are tentative and the co-ordination committee may reallocate the funds as per 

actual needs. 

Table 10.7: Cost estimates for the infrastructure development in the affected area of 

Demwe Lower H.E. project 

S. No Particulars Amount (in Rupees) 

1 Training Programme 21600000 

2 Merit Scholarship 15900000 

3 Marriage Grant 4080000 

4 Income Generation Scheme 25000000 

5 Education facilities 166000000 

6 Bus stops/rain shelters 8200000 

7 Construction of footpaths 24600000 

8 Support Services for Agricultural and Horticultural Activities 15000000 

9 Women Technology Park 19000000 

10 Protection of Cultural Heritage and Old Monuments 50000000 

12 Training and Assistance to fishermen 15000000 

13 Communication facilities 60000000 

14 Community welfare centers 45000000 

15 Transportation 35000000 

16 Recreation Facilities 25000000 

17 Public Library 15000000 

18 Crafts and Skill up gradation 26000000 

19 Water supply system 50000000 

20 Market Complex 40000000 


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S. No Particulars Amount (in Rupees) 

21 Miscellaneous (Creche, Graveyard, Crematorium etc) 60000000 

22 Health delivery system 118676000 

Total 839056000 

10.9 EVALUATION AND MONITORING 

The monthly report of execution of R & R plan will be sent to Corporate R & R 

cell, Athena Demwe Power Private Ltd (ADPP Ltd), which will be monitored by 

the Managing Director. The committee to oversee this will have the following 

members. 

i) Managing Director, ADPP Ltd or his/her representative Chairman 

ii) General Manager (Project), ADPP Ltd Member 

iii) Head of R & R Cell, ADPP Ltd Member Secretary 

iv) Head of the Corporate Planning Member 

v) A representative from Corporate Finance Deptt. Member 

In addition to an internal committee (above), it is suggested to constitute another 

committee in order to avoid any dispute between project authorities and the 

affected persons. The committee will include representatives of district 

administration, elected members, project authority, panchayat, member etc as 

per the provision of NRRP 2007. The committee will comprise of followings: 

i. District Magistrate, Lohit or his/her representative Chairman 

ii. ADC, Namsai Member 

iii. Representative of Panchayat members of affected villages Member 

iv. Woman (social worker) from the affected area Member 

v. Representative of well known NGO in the area Member 

vi. Representative of Managing Director ADPP Ltd Member 

vi. Head of the R & R Cell (ADPP Ltd) Member 

vii. Land Acquisition Officer of the project Member 


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The financial budget for the day to day expenditure of the committees would be 

Rs. 50,00,000 (Rs. Fifty lakhs) for five years. The expenditure includes TA and 

DA of participants, running cost, stationeries etc. 

10.10 FINANCIAL PACKAGE FOR R & R AND LOCAL AREA DEVELOPMENT 

PLAN 

Total financial package for the Rehabilitation and Resettlement plan of Demwe 

Lower H.E. project is budgeted as follows: 

a. Compensation for land & trees Rs. 1560.15 Lakhs 

b. R&R Grant Rs.706.40 Lakhs 

c. LADP provisions Rs. 8390.56 Lakhs 

d. Monitoring & Evaluation Rs. 50 Lakhs 

Out of the above, since compensation for land & trees would be exclusively met 

out from the land compensation grants under DPR, the total package for R&R 

and LADP under EIA/EMP amounts to 9146.96 lakhs. 


10-46 

CISMHE


ATHENA DEMWE POWER PRIVATE LIMITED 

DEMWE LOWER H.E. PROJECT, LOHIT, A.P. 

APPLICATION FORM FOR 

TRAINING PROGRAMME 

1. Name of the applicant ( in block letters): -------------------------------- 

2. Fathers Name : -------------------------------- 

3 Date of birth : -------------------------------- 

4. Qualification : ------------------------------- 

5. Residential Address : ------------------------------- 

6. Name of head of family : ------------------------------- 

From whom land acquired (PAP) 

7. Relation of applicant 

With head of family (PAP) 

: ------------------------------- 

8. Cast : Gen SC OBC ST 

9. Land details 

a) Name of the village (S) 

from where land acquired. 

: 

b) Area of the land acquired : 

(in ha.) and taken possession 

by ADPP, Ltd 

c) Land left (in ha) : -------------------------------d) 

whether the family has been 

declared landless by R&R Officer 

: -------------------------------e) 

Whether the family member 

has got employment in ADPP, Ltd 

R&R scheme. 

: Yes No. 

f) If Yes Name of employee : ------------------------------g) 

whether SC/ST/OBC/Gen. : ------------------------------- 

10. a) Present occupation of 

the applicant. 

: ------------------------------- 

b) Annual income from the : ------------------------------- 

Annexure-I i 

CISMHE 

ANNEXURE-I 

Attested 

photograph


Annexure-I ii 

CISMHE 

11. 

occupation. 

Choice of vocations for 

For which applied 

(please put a tick mark 

: 

: 

i) Food processin 

ii) Mushroom cultivation 

iii) Computer course 

iv) Dairy farming 

v) Poultry farming 

vi) Organic farming 

vii) Sericulture 

viii) Apiculture 

ix) Fish culture 

x) Knitting 

xi) Sewing 

xii) Any other please specify 

12. Certificates enclosed 

i) 

ii) 

iii) 

iv) 

13. Declaration: 

I here by declare that all the particulars furnished in this application are complete are true to the 

best of my knowledge. I shall abide by the rules and conditions mentioned in this scheme for PAFs. 

Signature of the applicant 

Name : 

Date : 

Place : 

Verified that the particulars of the applicant Sh/Smt./Km. ------------------------------ /daughter/wife 

of -------------------------------------- are true. 

Date : 

Signature of Gram Pradhan 

Name with stamp:




APPLICATION FORM FOR THE 

MERIT SCHOLARSHIP SCHEME 


2. Fathers Name : -------------------------------- 

3 Date of birth : -------------------------------- 



6. Correspondence address : ------------------------------- 





: ------------------------------- 





: 

b) Area of the land acquired : 


by ADPP, Ltd 




: -------------------------------e) 



R&R scheme. 

: Yes No. 



11. a) Present occupation of : ------------------------------- 


Annexure-II i 

CISMHE 

ANNEXURE-II 

Attested 

photograph


Annexure-II ii 

CISMHE 

b) Annual income from the 

occupation. 

: ------------------------------- 

12. Name of the school/institute/University: 

In which applicant studies 

----------------------------------- 

13. Name of the class/ course/diploma/degree 

for which scholarship is applied 

----------------------------------- 

14 Tenure of the class/course/diploma/degree ----------------------------------- 


i) 

ii) 

iii) 

iv) 





Name : 

Date : 

Place : 


of -------------------------------------- are true. 

Signature of Principal Signature of Gram Pradhan 

Name with stamp Name with stamp: 

Date Date :




APPLICATION FORM FOR 

INCOME GENERATION SCHEME 


2. Fathers Name : -------------------------------- 

3 Date of birth : -------------------------------- 







: ------------------------------- 





: 

b) Area of the land acquired 


by ADPP, Ltd 

: 




: -------------------------------e) 



R&R scheme. 

: Yes No. 



10. a) Present occupation of 


: ------------------------------b) 

Annual income from the 

occupation. 

: ------------------------------- 

Annexure-III i 

CISMHE 

ANNEXURE-III 

Attested 

photograph


11. Choice of unit/assets : 

For which applied financial assistance 

Required (please put a tick mark : 

CISMHE 

i) Food processing 

ii) Mushroom cultivation unit 

iii) Computer unit 

iv) Dairy farming assets 

v) Poultry farming assets 

vi) Organic farming assets 

vii) Sericulture assets 

viii) Apiculture assets 

ix) Fish culture assets 

x) Knitting Machines 

xi) Sewing machines 

xii) Business 

Xiii) Bakery unit 

xiv) Handicraft 

xv) Any other please specify 


i) 

ii) 

iii) 

iv) 





Name : 

Date : 

Place : 


of -------------------------------------- are true. 

Signature of Gram Pradhan 

Name with stamp: 

Annexure-III ii


CISMHE 

11 

DISASTER MANAGEMENT PLAN 


Disasters in case of hydroelectric power projects may take place due to natural 

reasons such as flood and earthquakes or may take place due to sabotage, 

safety failures and due to technical reasons .The Disaster Management Plan 

deals with the management practices to be adopted to counter the disasters, 

emerging out of any of the above listed causes. In case of Demwe Lower HEP, 

the anticipated disasters could be due to earthquake, flood or technological 

failures of the project or the projects constructed in the upstream course of river 

Lohit and its tributaries. The upper reaches of Lohit basin are frequented by 

earthquakes from time to time and the catchment has a history of excessive 

downpour which has caused massive floods. Till recent past, the communication 

of natural disasters taking places in the upper reaches of the catchment was 

hardly being received by the people living in the downstream area’s, at the onset 

of the disaster, since, the valley was not having any project of economic 

importance either in the upper reaches or in the downstream. With the 

advancement in technology and communication network, the exchange of news 

and prediction of likelihood of disastrous events at a faster pace has made it 

possible to counter the threats so emerging. The location of different proposed 

projects in the upstream reaches of river Lohit is given in Figure 1.1 

It is important to mention here that the Disaster Management of different hydro 

projects needs to be integrated among the various power developers because 

the river Lohit and its tributaries are proposed for cascade power development 

and dealing with the disasters in isolation would neither be possible nor adequate 

at individual project level. In case of the disaster taking place in the northernmost 

project, the brunt of the same will be felt by every body down the valley. The 

Environmental Management Plan – Disaster Management Plan 

11-1


precautionary steps to be taken to make the public aware about various disasters 

include the following: 

1. The public should be made aware about different kind of disasters such as 

natural disasters, disasters emanating from seismic concerns, manmade 

disasters and technological disasters in general. 

2. The public should also be told about the measures which are required to 

be taken incase of disasters .This can be achieved by organizing seminars 

.By distributing awareness pamphlets or by conducting workshops on 

management practices. The public should also be made aware of 

interpreting the electronic communication made in this regard with the help 

of sirens and hooters etc. 

3. The public should also be made aware as what to do at the time of 

occurrence of disasters and how to provide first aid to the affected 

persons and where to contact for medical help 

11.2 SEISMIC CONCERNS AND DISASTER MANAGEMENT 

The project area of Demwe Lower HEP as such falls in the seismic zones V 

which is considered as vulnerable. A detailed account of the geology and geomorphological 

parameters of the study area had been presented in Geology 

chapter of EIA report. The area has experienced earthquakes of moderate to 

severe intensity in the past. The epicenters of major earthquakes in and around 

the project area of Demwe Lower HEP are related to mega and intermediate 

lineaments and due design parameters have been taken care in the design of 

project appurtenants. However, from safety point of view, a plan of seismic 

surveillance of the area by establishing a seismic monitoring station is proposed. 

Detailed dam site investigations have been conducted from geological point of 

view and design of dams has been done accordingly. 

11.2.1 Seismic Station 

For mitigation of the seismic hazard, the only option available is to upgrade our 

knowledge on the geo-dynamics of earthquakes and to utilize the state-of-the-art 


CISMHE 

11-2


to constraint the motion characteristics. This would help in seismic designing of 

the components of the project. The reservoir induced seismicity concerns, 

however, requires a special emphasis for judging the effect of impoundment of 

the reservoir on seismic status of the area. With this background, it is proposed 

that a seismic observatory may be made compatible with IMD National Grid for 

recording and analyzing the nation-wide seismic activity. This would not only 

help the project authorities to plan the disaster management scheme related to 

the project but will also be helpful for the other projects in the area. 

11.3 Dam Break Study 

Dam break may be summarized as the partial or catastrophic failure of a dam 

leading to the uncontrolled release of water. Such an event can have impacts on 

the land and communities downstream of the failed structure. A dam break may 

result in a flood wave up to tens of meters deep traveling along a valley at quite 

high speeds. The impact of such a wave on developed areas can be devastating. 

Such destructive force comes as an inevitable loss of life, if advance warning and 

evacuation is not planned. Additional features of such extreme flooding include 

movement of large amounts of sediment (mud). 

11.3.2 Objective of dam break modeling 

The first European Law on dam break was introduced in France in 1968 following 

the earlier Malpasset Dam failure. Since then many countries have also 

established requirements and in others, dam owners have established guidelines 

for assessment. In India, risk assessment and disaster management plan has 

been made a mandatory requirement while submitting application for 

environmental clearance in respect of river valley projects. The extreme nature of 

dam break floods means that flow conditions will far exceed the magnitude of 

most natural flood events. Under these conditions flow will behave differently to 

conditions assumed for normal river flow modeling and areas will be inundated 

that are not normally considered. This makes dam break modeling a separate 

study for the risk management and disaster management plan. The objective of 

dam break modeling or flood routing is to simulate the movement of a dam break 


CISMHE 

11-3


flood wave along a valley or indeed any area downstream that would flood as a 

result of dam failure. The key information required at any point of interest within 

this flood zone is generally: 

� Travel time of flood water 

� Peak water level – extent of inundation 

� Peak discharge 

� Duration of flooding 

11.3.3 Scope of present study 

The present study for the Demwe Lower H.E. Project comprises of the following 

hydrodynamic simulations due to occurrence of: 

- PMF with Dam break with initial reservoir level at FRL 

- PMF discharge with no dam break 

- PMF without dam in place (virgin condition); 

11.3.4 Dam break modeling process 

Generally, dam break modeling can be carried out by either i) scaled physical 

hydraulic models or ii) mathematical simulation using computer. A modern tool to 

deal with this problem is the mathematical model, which is most cost effective 

and approximately solves the governing flow equations of continuity and 

momentum by computer simulation. A flow chart for mathematical modeling is 

given at the end of this chapter. Mathematical modeling of dam breach floods can 

be carried out by either one dimensional analysis or two dimensional analyses. In 

one dimensional analysis, the information about the magnitude of flood, i.e., 

discharge and water levels, variation of these with time and velocity of flow 

through breach can be had in the direction of flow. In the case of two 

dimensional analyses, the additional information about the inundated area, 

variation of surface elevation and velocities in two dimensions can also be 

forecast. One dimensional analysis is generally accepted when valley is long and 

narrow and the flood wave characteristics over a large distance from the dam are 

of main interest. The basic theory for dynamic routing in one dimensional 


CISMHE 

11-4


analysis consists of two partial differential equations originally derived by Barre 

De Saint Venant in 1871. The equations are: 

i. Conservation of mass (continuity) equation 

a. (∂Q/∂X) + ∂(A + A0) / ∂t - q = 0 

ii. Conservation of momentum equation 

b. (∂Q/∂t) + { ∂(Q 2 /A)/∂X } + g A ((∂h/∂X ) + Sf + Sc ) = 0 

c. where Q = discharge; 

i. A = active flow area; 

ii. A0 = inactive storage area; 

iii. h = water surface elevation; 

iv. q= lateral outflow; 

v. X = distance along waterway; 

vi. t = time; 

11.3.4 HEC-RAS Model 

vii. Sf = friction slope; 

viii. Sc = expansion contraction slope and 

ix. g = gravitational acceleration. 

Selection of an appropriate model to undertake dam break flood modeling is 

essential to ensure to achieve the right balance between modeling accuracy and 

cost in terms of time spent developing the model setup. In the instant case HEC- 

RAS version 4.0 model released by Hydrologic Engineering Center of U.S. Army 

Corps of Engineers in March 2008 has been selected. HEC-RAS is an integrated 

system of software, designed for interactive use in a multi-tasking environment. 

The system is comprised of a graphical user interface, separate hydraulic 

analysis components, data storage and management capabilities, graphics and 

reporting facilities. The model contains the advanced features for dam break 

simulation. 

The present version of HEC-RAS system contains two one-dimensional hydraulic 

components for: i) Steady flow surface profile computations; ii) unsteady flow 


CISMHE 

11-5


simulation. The steady/unsteady flow components are capable of modeling 

subcritical, supercritical, and mixed flow regime water surface profiles. The 

system can handle a full network of channels, a dendric system, or a single river 

reach. The basic computational procedure is based on the solution of one- 

dimensional energy equation. Energy losses are evaluated by friction (Manning’s 

equation) and contraction/expansion (coefficient multiplied by the velocity head). 

The momentum equation is utilized in situations where the water surface profile is 

rapidly varied. The graphics include X-Y plots of the river system schematic, 

cross-sections, profiles, rating curves, hydrographs, and many other hydraulic 

variables. Users can select from pre-defined tables or develop their own 

customized tables. All graphical and tabular output can be displayed on the 

screen, sent directly to a printer, or passed through the Windows clipboard to 

other software, such as word processor or spread sheet. Reports can be 

customized as to the amount and type of information desired. 

11.3.5 Model Stability during unsteady flow simulation 

HEC-RAS uses an implicit finite difference scheme. The common problem of 

instability in the case of unsteady flow simulation can be overcome by suitable 

selection of following; 

1. Cross section spacing along the river reach 

2. Computational time step 

3. Theta weighing factor for numerical solution 

4. Solution iterations 

5. Solution tolerance 

6. Weir and spillway stability factors 

13.3.5.1 Cross section spacing 

The river cross sections should be placed at representative locations to describe 

the change in geometry. Additional cross sections should be added at locations 

where changes occur in discharge, slope, velocity and roughness. Cross sections 

must also be added at levees, bridges, culverts, and other structures. Additional 

cross sections should be added at locations where changes occur in discharge, 


CISMHE 

11-6


slope, velocity, and roughness to describe the change in geometry. Bed slope 

plays an important role in deciding the cross section spacing. Streams having 

steep slope require cross sections at a closer spacing say 500 m or so. For larger 

uniform rivers with flat slope the cross section spacing can be kept from 1000m 

to 3000m. 

11.3.5.2 Computational time step 

Stability and accuracy can be achieved by selecting a computational time step 

that satisfies the current condition; 

Cr = Vw(∆t/∆x)≤1.0 

Therefore: ∆t≤(∆x/Vw) 

Where: Vw = Flood wave speed 

V = Average velocity of flow 

∆x = Distance between the cross sections 

∆t = Computational time step 

For most of the rivers the flood wave speed can be calculated as: 

Vw = dQ/dA 

However, an approximate way of calculating flood wave speed is to multiply the 

average speed by a factor. Factors for various channel shapes are shown in the 

table below 

Channel Shape Ratio (Vw/V) 

Wide rectangular 1.67 

Wide parabolic 1.44 

Triangular 1.33 

Natural Channel 1.5 

11.3.5.3 Theta weighing factor 

Theta is a weighing factor applied to the finite difference approximations when 

solving the unsteady flow equations. Theoretically Theta can vary from 0.5 to 1.0. 

Theta of 1.0 provides the most stability, while Theta of 0.6 provides the most 

accuracy. 


CISMHE 

11-7


11.3.5.4 Solution iteration 

At each time step derivatives are estimated and the equations are solved. All the 

computational nodes are then checked for numerical error. If the error is greater 

than the allowable tolerances, the program will iterate. The default number of 

iterations in HEC-RAS is set to 20. Iteration will improve the solution. 

11.3.5.5 Solution tolerances 

Two solution tolerances can be set or changed by the user: i) water surface 

calculation ii) storage area elevation. Making the tolerance larger can reduce the 

stability problem. Making them smaller can cause the program to go to the 

maximum number of iterations every time. 

11.3.5.6 Weir and spillway stability factor 

Weirs and spillways can often be a source of instability in the solution. During 

each time step, the flow over a weir/spillway is assumed to be constant. This can 

cause oscillations by sending too much flow during a time step. One solution is to 

reduce the time step. 

11.3.6 Description of the project 

Demwe Lower Hydroelectric Project is a run-of-the-river scheme planned across 

Lohit river, near Parasuram Kund/ Brahma Kund in Lohit district of Arunachal 

Pradesh. The project envisages construction of 163 m high concrete gravity dam 

(above deepest foundation level) across Lohit River. The Full Reservoir Level 

(FRL) and Maximum Water Level (MWL) for the project are at EL 424.8 m. The 

MDDL is at EL 408 m. The intake invert level is at EL 381 m. The reservoir 

extends about 23 km upstream of the dam. There are 12 sluice spillway gates of 

size 8.6 m x 11 m, apart from a surface spillway bay of 12.5 m x 18.0 m. The 

gross storage of the reservoir at FRL is 516.38 MCM. The dead storage up to 

MDDL is 345.18 MCM. The catchment area at the project site is 20174 sq. km. 

The design flood (PMF) for the project has been estimated as 28500 cumec. The 

maximum non-overflow section of Demwe Lower dam is given in Figure 11.2. 

The upstream elevation of the dam is given in Figure 11.3. 


CISMHE 

11-8


Breach 

Formation 

Modelling 

Parameters 

Base flow 

conditions 

Modelling 

Parameters 

Reservoir 

Level 

Debris & 

Sediments 

Sensitivity 

Analyses 

Base flow 

conditions 

Sensitivity 

Analyses 

Structural 

failure 

Partial 

failure 

Secondary 

Structures 

Data Collection 

Flood 

Hydrograph 

Define Dambreak 

Aims & Objectives 

(Mapping format & 

data requirements) 

Flood 

Routing 

Mapping 

& 

Data Output 


Additional 

Data 

Requirements? 

Additional 

Data 

Requirements? 

FLOW CHART OF DAM BREAK MODELLING PROCESS 

CISMHE 

11-9



CISMHE 

Figure 11.2: Maximum non-overflow section of Demwe Lower dam 

11-10



CISMHE 

Figure 11.3: Upstream elevation of Demwe Lower dam 

11-11


11.3.7 INPUT DATA AND MODEL SETUP 

11.3.7.1 Data required for dam break modelling 

Undertaking a dam break analysis requires following range of data in 

general: 

i. Cross sections of the river from dam site and up to location downstream of 

the dam to which the study is required 

ii. Stage-volume relationship for the reservoir 

iii. Salient features of the all hydraulic structures at the dam site and also in 

the study reach of the river 

iv. Design flood hydrograph 

v. Stage-discharge relationship at the last river cross section of the study area 

vi. Manning’s roughness coefficient for different reaches of the river under 

study 

vii. Rating curve of all the hydraulic structures in the study reach of the river 

viii. Topographic map of the downstream area for preparation of inundation 

map after dam break studies 

11.3.7.2 Dam break model set up for Demwe Lower H.E. Project 

For dam break model setup and other hydrodynamic model set up for 

Demwe Lower H.E. Project, the different components of the project have 

been represented in the model as following: 

Lohit river 

The Lohit river for a length of 58 km downstream of Demwe Lower dam site 

has been represented in the model by cross sections taken at varying 

intervals depending upon topography. The Lohit river cross section at dam 

axis has been connected to a storage area representing the reservoir. As 

the dam breach flood levels far exceed the normal flood level marks and 

the flood spreads beyond the normal river course, the Manning’s 

roughness coefficient for the dam break studies should be assumed 

normally more than the other hydro-dynamic studies. The Manning’s 

roughness coefficient for the first 10 km of the river reach downstream of 

dam has been taken as 0.040 considering the bouldery river beds with 

grassy banks of hilly terrain. From 10 to 58 km reach of the river the river 


11-12 

CISMHE


bed is sandy with very wide alluvial flood plains thus the Manning’s 

roughness coefficient has been taken as 0.035 to account for the river bed 

& flood plain resistance. 

Reservoir 

The reservoir has been represented in the model by storage area of the 

graphical editor of the model and its Elevation-volume relationship has 

been specified therein. The stage – volume relationship of the reservoir as 

used in the model set up is given in Table 11.1 

Dam and Spillway 

The concrete gravity dam of the project has been represented in the model 

by its crest length and crest level at the cross section just downstream of 

the reservoir. For the dam break study the breach plan data has been 

specified at dam location. The surface spillway and sluice spillway of the 

project have been represented as gated inline structures at the dam 

location, with their crest level, gate size and number of gates specified 

therein. The HEC-RAS model set up for dam and spillway is given in 

Figure 11.4. 

Table 11.1: Elevation-Volume relationship of reservoir 

ELEVATION CUMULATIVE VOLUME ELEVATION CUMULATIVE VOLUME 

(m) 

(million cubic meter) 

(m) 

(million cubic meter) 

400 274.18 413 393.08 

401 283.06 414 403.13 

402 291.93 415 413.18 

403 300.81 416 423.23 

404 309.68 417 433.28 

405 318.56 418 443.34 

406 327.43 419 453.39 

407 336.31 420 463.44 

408 345.18 421 474.47 

409 354.05 422 485.50 

410 362.93 423 496.53 

411 372.98 424 507.56 

412 383.03 425 518.59 


11-13 

CISMHE


Elevation (m) 

550 

500 

450 

400 

350 

Demwe Lower 

River = Lohit Reach = Dem we-ds RS = 80 

300 

0 100 200 300 400 500 600 

Station (m) 

Figure 11.4: HEC-RAS Model set up for dam and spillway 

Legend 

Ground 

Bank Sta 

Upstream Boundary 

Normally upstream boundary for any hydrodynamic study is the flood 

hydrograph. This flood hydrograph can be corresponding to a flood of 

specific return period, Standard Project Flood (SPF) or Probable Maximum 

Flood (PMF). For the dam break model simulation, the Probable Maximum 

Flood (PMF) given in Table 11.2 has been considered as the upstream 

boundary. The same has been impinged in to the reservoir as inflow 

hydrograph. 

Table 11.2: Probable Maximum Flood (PMF) 

Time Discharge Time Discharge Time Discharge 

(hours) (cumec) (hours) (cumec) (hours) (cumec) 

0 2001 44 20105 88 7134 

1 2001 45 20036 89 6699 

2 2002 46 20242 90 6290 

3 2007 47 20729 91 5908 

4 2019 48 21484 92 5555 

5 2044 49 22497 93 5230 

6 2091 50 23718 94 4932 

7 2176 51 25016 95 4655 


11-14 

CISMHE


Time 

(hours) 

Discharge 

(cumec) 

Time 

(hours) 

Discharge 

(cumec) 

Time 

(hours) 

Discharge 

(cumec) 

8 2328 52 26226 96 4431 

9 2585 53 27179 97 4265 

10 2970 54 27773 98 3750 

11 3493 55 28019 99 3164 

12 4154 56 28500 100 2552 

13 4953 57 27879 101 2016 

14 5867 58 27674 

15 6830 59 27404 

16 7767 60 27051 

17 8609 61 26603 

18 9333 62 26055 

19 9974 63 25387 

20 10622 64 24594 

21 11370 65 23683 

22 12271 66 22670 

23 13320 67 21593 

24 14497 68 20509 

25 15783 69 19465 

26 17128 70 18481 

27 18433 71 17562 

28 19595 72 16703 

29 20521 73 15908 

30 21163 74 15181 

31 21547 75 14509 

32 21760 76 13868 

33 21886 77 13236 

34 21980 78 12595 

35 22045 79 11949 

36 22064 80 11318 

37 22034 81 10716 

38 21952 82 10143 

39 21796 83 9596 

40 21554 84 9068 

41 21216 85 8558 

42 20807 86 8066 

43 20398 87 7591 


11-15 

CISMHE


Downstream Boundary 

The Normal depth has been used as the downstream boundary for the dam 

break model set up. The downstream boundary has been applied at the 

cross section of Lohit river 58 km d/s of Demwe Lower dam axis. The HEC- 

RAS Model set up for the dam break studies is given in Figure 11.5. 


11-16 

CISMHE


Demwe-ds 

CISMHE 

-14000 

-15500.* 

-45000.* 

-18000.* 

-51000.* -41500.* 

-20000.* 

-53500.* 

-40000.* 

-21500.* 

-55500.* 

-36500.* 

-23500.* 

-58000 

-32500.* -27000.* 

None Geo-Ref of Geo-Ref the Non XS's user Non Geo-Ref interpolated are entered Geo-Ref user XS interpolated XS erenced entered XS ( XS) 


Loh i t 

-3000 

-4500.* 

-5000 

-7000.* 

-7500.* 

-8500.* 

-9500.* 

Figure 11.5: HEC-RAS Model Set up for Dam Break Studies 

11-17 

200 

Reserv oir


11.3.8 BREACH PARAMETERS AND DAM BREAK SIMULATION 

11.3.8.1 Selection of breach parameters for Dam Break study 

For any dam break study it is extremely difficult to predict the chances of 

failure of a dam, as prediction of the dam breach parameters and timing of the 

breach are not within the capability of any of the commercially available 

mathematical models. However, assuming the dam fails, the important 

aspects to deal with are, time of failure, extent of overtopping before failure, 

size, shape and time of the breach formation. Estimation of the dam break 

flood will depend on these parameters. 

The breach characteristics that are used as input to the existing dam break 

models are i) Final bottom width of the breach, ii) Final bottom elevation of the 

breach, iii) Left and right side slope of the breaching section iv) Full formation 

time of breach, and v) Reservoir level at time of start of breach. The breach 

formation mechanism is, to a large extent, dependent on the type of dam and 

the cause due to which the dam failed. 

A study of the different dam failures indicate that concrete arch and gravity 

dams breach by sudden collapse, overturning or sliding away of the structure 

due to inadequate design or excessive forces that may result from 

overtopping, earthquakes and deterioration of the abutment or foundation 

material. 

As per the UK Dam Break Guidelines and U.S. Federal Energy Regulatory 

Commission (FERC) Guidelines, in the case of concrete gravity dams, the 

breach width should be taken between 0.2 to 0.5 times the crest length of the 

dam and full breach formation time should be taken instantaneous which may 

be practically taken as 0.2 to 0.25 hours. The full breach formation time for the 

dam break simulation of Demwe Lower H.E. Project has been considered as 

15 minutes. The final bottom elevation of the breach for sensitivity analysis 

has been taken corresponding to relatively weaker locations in the dam, such 

location of openings, galleries etc. Further, the final bottom elevation of the 

breach should be restricted to the reservoir bed level / natural ground level at 

the dam location due to nil reservoir storage below this level. 


11-18 

CISMHE


The manner in which the failure is to commence can be specified as one of 

the following: 

• At a specified stage (water surface elevation) of the reservoir and 

duration 

• At a specified time 

• At a specified stage (water surface elevation) of the reservoir 

11.3.8.2 Critical condition for dam break study 

The critical condition for a dam break study is when the reservoir is at Full 

Reservoir Level (FRL) and design flood hydrograph (PMF in the present case) 

is impinged. Accordingly, in the present study keeping the initial reservoir 

level 424 m, just near FRL, the reservoir routing has been carried out by 

impinging the PMF. For opening schedule of spillway gates the elevation 

controlled algorithm of HEC-RAS model has been used, where the spillway 

gate opening is controlled with the rise and fall of reservoir water level just 

upstream of dam. The upper and lower limits of reservoir level for PMF routing 

have been fixed corresponding to FRL (424.8 m) and MDDL (408 m) 

respectively. In order to get the maximum discharge through dam breach The 

maximum water level reached in the reservoir during routing is 424.8 m which 

occurs 55 hours 45 minutes after the impingement of PMF. The top of dam is 

at EL 426.8 m. Hence, it can be said that even initial reservoir level at FRL the 

PMF can be safely passed as the spillway capacity is adequate to negotiate 

the PMF. Further, this type of routing has been adopted in order to get the 

PMF peak and maximum dam break flood synchronized and thus resulting the 

maximum net total discharge just downstream of the dam. The discharge 

through spillway gates and the reservoir level as obtained during reservoir 

routing of PMF is shown in Figure 11.6. The dates given on the horizontal 

axis of the plot are the relative dates only, as used in HEC-RAS model set up. 


11-19 

CISMHE


Stage (m) 

440 

420 

400 

380 

360 

340 

320 

Plan: p01 River: Lohit Reach: Demwe-ds RS: 80 

30000 

300 

2400 1200 2400 1200 2400 1200 2400 1200 2400 

20Sep2008 21Sep2008 22Sep2008 

Tim e 

23Sep2008 

25000 

20000 

15000 

10000 

5000 

0 

Flow (m3/s) 

Legend 

Reservoir level 

Total outflow 

Surface spillway flow 

Sluice spillway flow 

Figure 11.6: Discharge through spillway and reservoir level during reservoir 

routing 

From Figure 11.6 it can be seen that the PMF can be safely passed by 

suitable operation of spillway gates. In order to get the maximum discharge 

through the breach and most critical dam break flood, the dam has been 

assumed to breach 55 hours 45 minutes after the impingement of PMF i.e. on 

22 Sep 2008, 0745 hours as per simulation time adopted, when the reservoir 

level is at FRL. 

11.3.8.3 Breach parameters selected for sensitivity analysis of dam break 

simulation 

Considering the criteria for selection of breach parameters and critical 

condition for the dam break study as discussed earlier, two different cases of 

breach parameters as given in (Table 11.3) have been identified for sensitivity 

analysis of dam break simulations. In all these two cases, the initial breach 

elevation has been taken corresponding to the top of dam (EL 426.8 m). The 

final bottom elevation of the breach has been taken corresponding to gallery 

levels. The breach side slope has been taken as zero as applicable for 

concrete gravity dam. The time of failure has been taken as 15 minutes for the 

instantaneous failure of non- overflow blocks. 


11-20 

CISMHE


Table 11.3: Breach parameters considered for sensitivity analysis 

Case 

No. 

Breach Elevation 

(m) 

Initial Final 

Breach 

Width (m) 

Breach 

Develo- 

pment 

Time 

(Minutes) 

Max. 

Discha- 

rge just 

d/s of 

dam 

(cumec) 

Remarks 

1. 426.8 390 120 15 55775 5 non-overflow blocks 

right of the sluice spillway 

considered to break up to 

the gallery at EL 390 m. 

2. 426.8 360 45 15 55309 2 non-overflow blocks right 

of the sluice spillway 

considered to break up to 

the gallery at EL 360 m. 

As case-1 generates the maximum discharge through the breach width of 120 

m, the same has been finalized for detailed outputs of dam break simulation. 

11.3.8.4 Dam break simulation: Breach width 120m, breach depth 36.8 m 

In the present case, five non-overflow blocks right of the sluice spillway 

(Figure11.2) with total width of 120 m considered to break till the gallery at EL 

390 m, 55 hours 45 minutes after the occurrence of PMF. In the model set up 

the first ordinate of PMF hydrograph has been assumed to occur on 19 Sep 

2008 at 2400 hour (which is a relative time used for mathematical modelling 

only). Accordingly, the breach has been assumed to start on 22 Sep 2008 at 

0745 hours. The maximum discharge through breach has been found as 

26526 cumec occurring on 22 Sep 2008 at 0800 hours or (56 hours after the 

impingement of PMF hydrograph). The time series plot of discharge through 

dam breach is given in Figure 11.7. 


11-21 

CISMHE


FLO W (M3/S) 

30000 

25000 

20000 

15000 

10000 

5000 

Figure 11.7: Discharge time series through dam breach 

80 INL STRUCT 

Time series of discharge 

0 

2400 1200 2400 1200 2400 1200 2400 1200 2400 

20Sep2008 21Sep2008 

Tim e 

22Sep2008 23Sep2008 

Note: The dates and time are relative dates and time as used in the HEC-RAS 

model set up 

The dam break flood hydrograph just downstream of Demwe Lower dam 

(comprising of total discharge through spillway and dam breach) with peak 

55775 cumec is given in Figure 11.8. The time of occurrence of the flood 

peak is on 22 Sep 2008 at 0800 hours, which is 15 minutes after the start of 

breach. The peak segment of the hydrograph (Figure 11.8) last for about 4 

hours. This is due to medium reservoir capacity, and the reservoir gets 

depleted quickly after the dam breach. 

The maximum discharge, water level and flood travel time at different 

locations of the Lohit river downstream of the dam are given in Table 11.4. 

From the Table 11.4, it can be seen that the dam breach flood peak just 

downstream of the dam is 55775 cumec, which reduces to 40084 cumec at 

the chainage 58000 m downstream of the dam axis. Here it is important to 

mention that the attenuation pattern of any dam break flood hydrograph 

depends upon the reservoir capacity, variability of river cross sections in the 

study reach and the time base of the peak segment of the flood hydrograph. If 


11-22 

CISMHE


FLOW (M3/S) 

60000 

50000 

40000 

30000 

20000 

10000 

the time base of the peak segment of the flood hydrograph is more its 

attenuation along the downstream river reach will be relatively less. The flood 

peak attenuation of about 15000 cumec is basically due to medium reservoir 

capacity and variation in Lohit river cross section downstream of Demwe 

Lower dam. The average velocity of the flood wave is about 9 km/hour due to 

extensive widening of Lohit river course after 5 km downstream of proposed 

Demwe Lower dam axis. 

Figure 11.8: Dam break flood hydrograph due to Demwe Lower dam break 

LOHIT DEMWE-DS 0 


0 

2400 1200 2400 1200 2400 1200 2400 1200 2400 

20Sep2008 21Sep2008 

Tim e 

22Sep2008 23Sep2008 

Table 11.4: Maximum discharge, water level and flood wave travel time at different 

locations of Lohit river for Demwe Lower dam break (breach width 120m, 

breach depth 36.8m) 


11-23 

CISMHE


(Note: -100, -1000 etc denote the location of river cross sections 100 m, 1000 m d/s of dam axis) 

River 

Chainage (m) d/s 

of Demwe Lower 

dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit 0 Max WS 55775 296.37 323.56 0 

Lohit -100 Max WS 55770 294.87 322.68 0 

Lohit -200 Max WS 55766 292.17 322.71 0 

Lohit -300 Max WS 55759 288.57 321.92 0 

Lohit -400 Max WS 55750 293.57 322.73 0.01 

Lohit -600 Max WS 55738 299.27 321.07 0.01 

Lohit -1000 Max WS 55724 291.97 316.97 0.02 

Lohit -1500 Max WS 55713 290.47 313.00 0.03 

Lohit -2000 Max WS 55706 292.27 307.13 0.04 

Lohit -2500.* Max WS 55704 286.14 299.97 0.05 

Lohit -3000 Max WS 55688 280.00 295.56 0.07 

Lohit -3500.* Max WS 55682 278.00 293.21 0.09 

Lohit -4000 Max WS 55656 276.00 289.60 0.11 

Lohit -4500.* Max WS 53880 274.00 288.29 0.13 

Lohit -5000 Max WS 52721 272.00 288.17 0.17 

Lohit -5500.* Max WS 52569 269.50 287.27 0.21 

Lohit -6000 Max WS 52485 267.00 284.31 0.24 

Lohit -6500.* Max WS 52417 265.50 281.12 0.26 

Lohit -7000.* Max WS 52372 264.00 278.01 0.29 

Lohit -7500.* Max WS 52306 262.50 274.96 0.31 

Lohit -8000.* Max WS 52259 261.00 271.91 0.34 

Lohit -8500.* Max WS 52203 259.50 268.94 0.37 

Lohit -9000.* Max WS 52142 258.00 265.79 0.40 

Lohit -9500.* Max WS 52126 256.50 263.08 0.43 

Lohit -10000 Max WS 52123 255.00 259.50 0.47 

Lohit -10500.* Max WS 52108 250.37 254.93 0.50 

Lohit -11000.* Max WS 52089 245.75 250.36 0.52 

Lohit -11500.* Max WS 52081 241.13 245.72 0.55 

Lohit -12000.* Max WS 52072 236.50 241.12 0.58 

Lohit -12500.* Max WS 52057 231.88 236.33 0.61 

Lohit -13000.* Max WS 51985 227.25 231.74 0.64 

Lohit -13500.* Max WS 52025 222.63 226.47 0.67 

Lohit -14000 Max WS 51513 218.00 222.87 0.71 


11-24 

CISMHE


River 



dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit -14500.* Max WS 51224 216.69 222.00 0.76 

Lohit -15000.* Max WS 50983 215.38 220.97 0.82 

Lohit -15500.* Max WS 50765 214.06 219.85 0.87 

Lohit -16000.* Max WS 50575 212.75 218.69 0.92 


Lohit -17000.* Max WS 50230 210.12 216.29 1.01 

Lohit -17500.* Max WS 50121 208.81 215.07 1.06 

Lohit -18000.* Max WS 49973 207.50 213.85 1.11 

Lohit -18500.* Max WS 49827 206.19 212.62 1.15 

Lohit -19000.* Max WS 49731 204.88 211.38 1.20 

Lohit -19500.* Max WS 49602 203.56 210.14 1.24 

Lohit -20000.* Max WS 49510 202.25 208.90 1.28 

Lohit -20500.* Max WS 49386 200.94 207.66 1.33 

Lohit -21000.* Max WS 49306 199.63 206.41 1.37 

Lohit -21500.* Max WS 49264 198.31 205.15 1.41 

Lohit -22000 Max WS 49214 197.00 203.45 1.45 

Lohit -22500.* Max WS 49169 195.58 201.63 1.49 

Lohit -23000.* Max WS 49124 194.17 199.82 1.53 

Lohit -23500.* Max WS 49079 192.75 198.03 1.57 

Lohit -24000.* Max WS 49035 191.33 196.26 1.60 

Lohit -24500.* Max WS 48992 189.92 194.52 1.64 

Lohit -25000.* Max WS 48964 188.50 192.80 1.68 

Lohit -25500.* Max WS 48923 187.08 191.09 1.72 

Lohit -26000.* Max WS 48883 185.67 189.40 1.77 

Lohit -26500.* Max WS 48829 184.25 187.63 1.81 

Lohit -27000.* Max WS 48815 182.83 186.06 1.86 

Lohit -27500.* Max WS 48776 181.42 183.86 1.91 

Lohit -28000 Max WS 48628 180.00 182.31 1.97 

Lohit -28500.* Max WS 48495 178.50 181.46 2.05 

Lohit -29000.* Max WS 48313 177.00 180.52 2.13 

Lohit -29500.* Max WS 48147 175.50 179.42 2.19 

Lohit -30000.* Max WS 47991 174.00 178.25 2.25 

Lohit -30500.* Max WS 47836 172.50 177.02 2.31 

Lohit -31000.* Max WS 47690 171.00 175.74 2.36 


11-25 

CISMHE


River 



dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit -31500.* Max WS 47538 169.50 174.39 2.41 




Lohit -33500.* Max WS 47266 163.50 168.77 2.58 



Lohit -35000.* Max WS 47173 159.00 164.64 2.70 




Lohit -37000.* Max WS 47052 153.00 158.57 2.85 

Lohit -37500.* Max WS 46831 151.50 157.13 2.90 

Lohit -38000 Max WS 46575 150.00 156.39 2.95 

Lohit -38500.* Max WS 46367 149.50 155.81 3.02 

Lohit -39000.* Max WS 46216 149.00 155.22 3.08 

Lohit -39500.* Max WS 46024 148.50 154.64 3.15 

Lohit -40000.* Max WS 45884 148.00 154.05 3.21 

Lohit -40500.* Max WS 45704 147.50 153.46 3.27 

Lohit -41000.* Max WS 45530 147.00 152.87 3.34 

Lohit -41500.* Max WS 45401 146.50 152.29 3.40 

Lohit -42000.* Max WS 45237 146.00 151.70 3.46 

Lohit -42500.* Max WS 45122 145.50 151.13 3.52 

Lohit -43000.* Max WS 45014 145.00 150.55 3.59 

Lohit -43500.* Max WS 44918 144.50 149.95 3.65 

Lohit -44000.* Max WS 44859 144.00 149.32 3.71 

Lohit -44500.* Max WS 44783 143.50 148.66 3.77 


Lohit -45500.* Max WS 44648 142.50 147.27 3.90 

Lohit -46000.* Max WS 44529 142.00 146.53 3.97 

Lohit -46500.* Max WS 44215 141.50 145.81 4.03 

Lohit -47000.* Max WS 43533 141.00 145.22 4.10 

Lohit -47500.* Max WS 42970 140.50 144.85 4.19 

Lohit -48000 Max WS 42594 140.00 144.65 4.29 


11-26 

CISMHE


River 



dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit -48500.* Max WS 42357 139.85 144.49 4.41 

Lohit -49000.* Max WS 42134 139.70 144.32 4.53 

Lohit -49500.* Max WS 41880 139.55 144.15 4.64 


Lohit -50500.* Max WS 41514 139.25 143.79 4.88 

Lohit -51000.* Max WS 41309 139.10 143.61 4.99 

Lohit -51500.* Max WS 41158 138.95 143.41 5.11 

Lohit -52000.* Max WS 41019 138.80 143.21 5.23 

Lohit -52500.* Max WS 40891 138.65 143.01 5.35 

Lohit -53000.* Max WS 40773 138.50 142.79 5.46 

Lohit -53500.* Max WS 40638 138.35 142.57 5.58 

Lohit -54000.* Max WS 40539 138.20 142.33 5.70 

Lohit -54500.* Max WS 40449 138.05 142.08 5.82 

Lohit -55000.* Max WS 40369 137.90 141.82 5.94 

Lohit -55500.* Max WS 40296 137.75 141.54 6.06 

Lohit -56000.* Max WS 40219 137.60 141.24 6.18 


Lohit -57000.* Max WS 40120 137.30 140.58 6.43 

Lohit -57500.* Max WS 40093 137.15 140.19 6.56 

Lohit -58000 Max WS 40084 137.00 139.74 6.68 

Note: .* indicates the cross section locations interpolated by HEC-RAS Model 

11.3.8.5 Time series plot of water level 

The plots of time series of water level for the entire simulation period of 101 

hours (from 19Jul2008 : 2400 hours to 24Sep2008 : 0500 hours) at the three 

cross sections one each at starting, middle and end of the study reach, is 

given in Figure 11.9. As the main concern for dam break study is the peak 

segment of stage/water level time series, the same has been plotted in 

Figure 11.10 at different downstream locations of Lohit river for a simulation 

period of 30 hours (from 22 Sep 2008 : 0200 hours to 22 Sep 2008: 2400 

hours), in order to get hourly change in water level. The same can be used for 

estimating the period of inundation corresponding to a particular elevation 

during the preparation of disaster management plan. 


11-27 

CISMHE


The plots of all the cross sections of Lohit river used for the study along with 

the maximum water level attained at that location due to dam break flood are 

given in Figure 11.11. The above plots are appended at the end. 

11.3.8.6 Dam Breach flood hydrograph 

The dam break flood hydrograph just downstream of the Demwe Lower dam 

for breach parameters corresponding to case-1 is also produced in tabular 

form in Table 11.5. 

Date and Time 

(hour : minute) as per 

HEC-RAS simulation period 

adopted 

Table 11.5: Dam break flood hydrograph 

Time as per normal 

notation 

(hour : minute) 

Discharge 

(cumec) 

19Sep2008 24:00 0 2000 

20Sep2008 01:00 1 2488 

20Sep2008 02:00 2 2700 

20Sep2008 03:00 3 2840 

20Sep2008 04:00 4 2948 

20Sep2008 05:00 5 2956 

20Sep2008 06:00 6 3000 

20Sep2008 07:00 7 3034 

20Sep2008 08:00 8 3068 

20Sep2008 09:00 9 3100 

20Sep2008 10:00 10 3108 

20Sep2008 11:00 11 3110 

20Sep2008 12:00 12 3121 

20Sep2008 13:00 13 3143 

20Sep2008 14:00 14 3177 

20Sep2008 15:00 15 3224 

20Sep2008 16:00 16 10982 

20Sep2008 17:00 17 11353 

20Sep2008 18:00 18 11265 

20Sep2008 19:00 19 11205 

20Sep2008 20:00 20 11171 

20Sep2008 21:00 21 11165 


11-28 

CISMHE


Date and Time 



adopted 


notation 


Discharge 

(cumec) 

20Sep2008 22:00 22 11190 

20Sep2008 23:00 23 11250 

20Sep2008 24:00 24 11350 

21Sep2008 01:00 25 13203 

21Sep2008 02:00 26 20431 

21Sep2008 03:00 27 20276 

21Sep2008 04:00 28 20201 

21Sep2008 05:00 29 20194 

21Sep2008 06:00 30 20233 

21Sep2008 07:00 31 20300 

21Sep2008 08:00 32 20380 

21Sep2008 09:00 33 20465 

21Sep2008 10:00 34 21530 

21Sep2008 11:00 35 23404 

21Sep2008 12:00 36 23315 

21Sep2008 13:00 37 23231 

21Sep2008 14:00 38 23149 

21Sep2008 15:00 39 23064 

21Sep2008 16:00 40 22971 

21Sep2008 17:00 41 22864 

21Sep2008 18:00 42 22738 

21Sep2008 19:00 43 22589 

21Sep2008 20:00 44 22413 

21Sep2008 21:00 45 22235 

21Sep2008 22:00 46 22075 

21Sep2008 23:00 47 21952 

21Sep2008 24:00 48 21887 

22Sep2008 01:00 49 21897 

22Sep2008 02:00 50 21992 

22Sep2008 03:00 51 22176 

22Sep2008 04:00 52 22440 

22Sep2008 05:00 53 22747 

22Sep2008 06:00 54 23066 

22Sep2008 07:00 55 23386 


11-29 

CISMHE


Date and Time 



adopted 


notation 


Discharge 

(cumec) 

22Sep2008 07:15 55:15 23465 

22Sep2008 07:30 55:30 25988 

22Sep2008 07:45 55:45 28710 

22Sep2008 08:00 56 55775 

22Sep2008 08:15 56:15 52968 

22Sep2008 08:30 56:30 50247 

22Sep2008 08:45 56:45 47671 

22Sep2008 09:00 57 45422 

22Sep2008 09:15 57:15 43455 

22Sep2008 09:30 57:30 41732 

22Sep2008 09:45 57:45 40217 

22Sep2008 10:00 58 38772 

22Sep2008 11:00 59 34225 

22Sep2008 12:00 60 31566 

22Sep2008 13:00 61 29840 

22Sep2008 14:00 62 23968 

22Sep2008 15:00 63 23925 


22Sep2008 17:00 65 24217 

22Sep2008 18:00 66 23845 

22Sep2008 19:00 67 23251 

22Sep2008 20:00 68 19341 

22Sep2008 21:00 69 19537 

22Sep2008 22:00 70 19341 

22Sep2008 23:00 71 16870 

22Sep2008 24:00 72 16940 

23Sep2008 01:00 73 15524 

23Sep2008 02:00 74 15224 

23Sep2008 03:00 75 14792 

23Sep2008 04:00 76 13845 

23Sep2008 05:00 77 13753 

23Sep2008 06:00 78 12597 

23Sep2008 07:00 79 11606 

23Sep2008 08:00 80 11534 


11-30 

CISMHE


Date and Time 



adopted 


notation 


Discharge 

(cumec) 

23Sep2008 09:00 81 10723 

23Sep2008 10:00 82 10003 

23Sep2008 11:00 83 9374 

23Sep2008 12:00 84 8865 

23Sep2008 13:00 85 8459 

23Sep2008 14:00 86 8152 

23Sep2008 15:00 87 7540 


23Sep2008 17:00 89 7269 

23Sep2008 18:00 90 7058 

23Sep2008 19:00 91 6801 

23Sep2008 20:00 92 6519 

23Sep2008 21:00 93 6225 

23Sep2008 22:00 94 5930 

23Sep2008 23:00 95 5643 

23Sep2008 24:00 96 5370 

24Sep2008 01:00 97 5121 

24Sep2008 02:00 98 4851 

24Sep2008 03:00 99 4436 

24Sep2008 04:00 100 3414 

24Sep2008 05:00 101 2716 

11.3.8.7 Longitudinal profile 

The longitudinal profile of the Lohit river for dam break condition is given in 

Figure 11.12 of the chapter. 

11.3.9 Maximum water level in Lohit river due to occurrence of PMF without 

dam break 

In order to assess the maximum water level at different locations of Lohit river 

downstream of Demwe Lower dam due to occurrence of PMF, without any 

dam break, the PMF has been routed through the reservoir assuming initial 

water level at FRL. Since FRL and MWL are same ie EL 424.8 m, hence no 

mitigation of flood is possible as no additional flood storage is available. 


11-31 

CISMHE


Further, the spillway capacity is adequate to negotiate the PMF hence the 

PMF can be safely passed through reservoir. In this case the spillway gate 

openings has been fully synchronised with the ordinates of PMF hydrograph. 


locations of the Lohit river downstream of the dam are given in Table 11.6. 

The average velocity of the flood wave is about 8 km/hour. 

Table 11.6: Maximum discharge, water level and flood wave travel time in Lohit river 

due to occurrence of PMF without dam breach 

River 

Chainage 

(m) d/s 

of 

Demwe 

Lower 

dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit 0 Max WS 28500 296.37 316.61 0 

Lohit -100 Max WS 28497 294.87 317.04 0 

Lohit -200 Max WS 28496 292.17 317.55 0 


Lohit -400 Max WS 28492 293.57 317.13 0.01 

Lohit -600 Max WS 28489 299.27 315.67 0.01 

Lohit -1000 Max WS 28482 291.97 312.04 0.02 

Lohit -1500 Max WS 28486 290.47 310.19 0.04 

Lohit -2000 Max WS 28485 292.27 302.59 0.05 

Lohit -2500.* Max WS 28483 286.14 294.42 0.07 

Lohit -3000 Max WS 28479 280.00 292.14 0.09 

Lohit -3500.* Max WS 28474 278.00 289.96 0.11 

Lohit -4000 Max WS 28465 276.00 286.79 0.14 

Lohit -4500.* Max WS 28452 274.00 285.44 0.16 

Lohit -5000 Max WS 28447 272.00 285.21 0.21 

Lohit -5500.* Max WS 28435 269.50 284.46 0.26 

Lohit -6000 Max WS 28433 267.00 281.65 0.3 

Lohit -6500.* Max WS 28431 265.50 278.86 0.32 

Lohit -7000.* Max WS 28426 264.00 276.08 0.35 

Lohit -7500.* Max WS 28424 262.50 273.31 0.38 

Lohit -8000.* Max WS 28421 261.00 270.48 0.41 


11-32 

CISMHE


River 

Chainage 

(m) d/s 

of 

Demwe 

Lower 

dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

Lohit -8500.* Max WS 28419 259.50 267.74 0.45 


Lohit -9500.* Max WS 28414 256.50 262.17 0.53 

Lohit -10000 Max WS 28413 255.00 258.59 0.57 

Lohit -10500.* Max WS 28410 250.37 253.99 0.6 

Lohit -11000.* Max WS 28410 245.75 249.43 0.63 

Lohit -11500.* Max WS 28407 241.13 244.77 0.67 

Lohit -12000.* Max WS 28406 236.50 240.21 0.7 

Lohit -12500.* Max WS 28404 231.88 235.39 0.73 

Lohit -13000.* Max WS 28404 227.25 230.9 0.77 

Lohit -13500.* Max WS 28402 222.63 225.64 0.8 

Lohit -14000 Max WS 28397 218.00 221.82 0.85 


Lohit -15000.* Max WS 28387 215.38 219.84 0.98 

Lohit -15500.* Max WS 28385 214.06 218.7 1.04 


Lohit -16500.* Max WS 28377 211.44 216.31 1.15 

Lohit -17000.* Max WS 28374 210.12 215.09 1.2 

Lohit -17500.* Max WS 28370 208.81 213.86 1.26 

Lohit -18000.* Max WS 28369 207.50 212.62 1.31 

Lohit -18500.* Max WS 28365 206.19 211.38 1.36 

Lohit -19000.* Max WS 28362 204.88 210.14 1.41 

Lohit -19500.* Max WS 28358 203.56 208.89 1.46 

Lohit -20000.* Max WS 28357 202.25 207.64 1.51 

Lohit -20500.* Max WS 28354 200.94 206.38 1.56 

Lohit -21000.* Max WS 28351 199.63 205.13 1.61 

Lohit -21500.* Max WS 28350 198.31 203.9 1.66 

Lohit -22000 Max WS 28348 197.00 202.24 1.71 

Lohit -22500.* Max WS 28346 195.58 200.44 1.75 

Lohit -23000.* Max WS 28345 194.17 198.65 1.79 

Lohit -23500.* Max WS 28343 192.75 196.9 1.84 

Lohit -24000.* Max WS 28342 191.33 195.17 1.88 


11-33 

CISMHE


River 

Chainage 

(m) d/s 

of 

Demwe 

Lower 

dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

Lohit -24500.* Max WS 28340 189.92 193.48 1.93 

Lohit -25000.* Max WS 28339 188.50 191.81 1.97 

Lohit -25500.* Max WS 28337 187.08 190.16 2.02 

Lohit -26000.* Max WS 28336 185.67 188.55 2.07 

Lohit -26500.* Max WS 28334 184.25 186.86 2.13 

Lohit -27000.* Max WS 28332 182.83 185.38 2.19 

Lohit -27500.* Max WS 28331 181.42 183.32 2.25 

Lohit -28000 Max WS 28329 180.00 181.78 2.32 

Lohit -28500.* Max WS 28325 178.50 180.86 2.41 

Lohit -29000.* Max WS 28321 177.00 179.77 2.5 

Lohit -29500.* Max WS 28318 175.50 178.57 2.57 

Lohit -30000.* Max WS 28313 174.00 177.27 2.63 

Lohit -30500.* Max WS 28309 172.50 175.87 2.69 

Lohit -31000.* Max WS 28308 171.00 174.38 2.74 









Lohit -35500.* Max WS 28295 157.50 162.05 3.16 


Lohit -36500.* Max WS 28292 154.50 159.14 3.25 

Lohit -37000.* Max WS 28291 153.00 157.58 3.3 

Lohit -37500.* Max WS 28287 151.50 156.11 3.34 

Lohit -38000 Max WS 28283 150.00 155.29 3.4 

Lohit -38500.* Max WS 28279 149.50 154.71 3.48 

Lohit -39000.* Max WS 28274 149.00 154.12 3.55 

Lohit -39500.* Max WS 28270 148.50 153.53 3.62 

Lohit -40000.* Max WS 28266 148.00 152.94 3.7 


11-34 

CISMHE


River 

Chainage 

(m) d/s 

of 

Demwe 

Lower 

dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

Lohit -40500.* Max WS 28262 147.50 152.35 3.77 

Lohit -41000.* Max WS 28258 147.00 151.76 3.84 

Lohit -41500.* Max WS 28254 146.50 151.17 3.91 

Lohit -42000.* Max WS 28250 146.00 150.58 3.98 

Lohit -42500.* Max WS 28246 145.50 149.99 4.05 

Lohit -43000.* Max WS 28242 145.00 149.4 4.12 

Lohit -43500.* Max WS 28239 144.50 148.82 4.19 

Lohit -44000.* Max WS 28235 144.00 148.25 4.26 

Lohit -44500.* Max WS 28232 143.50 147.67 4.33 

Lohit -45000.* Max WS 28229 143.00 147.05 4.4 

Lohit -45500.* Max WS 28226 142.50 146.4 4.47 

Lohit -46000.* Max WS 28223 142.00 145.74 4.55 


Lohit -47000.* Max WS 28195 141.00 144.48 4.7 

Lohit -47500.* Max WS 28171 140.50 144.08 4.8 

Lohit -48000 Max WS 28153 140.00 143.89 4.92 

Lohit -48500.* Max WS 28143 139.85 143.74 5.06 

Lohit -49000.* Max WS 28127 139.70 143.59 5.2 

Lohit -49500.* Max WS 28119 139.55 143.43 5.34 

Lohit -50000.* Max WS 28111 139.40 143.28 5.48 

Lohit -50500.* Max WS 28097 139.25 143.11 5.61 

Lohit -51000.* Max WS 28090 139.10 142.94 5.75 

Lohit -51500.* Max WS 28078 138.95 142.77 5.89 

Lohit -52000.* Max WS 28072 138.80 142.59 6.02 


Lohit -53000.* Max WS 28056 138.50 142.21 6.3 

Lohit -53500.* Max WS 28047 138.35 142 6.43 

Lohit -54000.* Max WS 28043 138.20 141.79 6.57 

Lohit -54500.* Max WS 28036 138.05 141.56 6.71 

Lohit -55000.* Max WS 28032 137.90 141.33 6.84 

Lohit -55500.* Max WS 28026 137.75 141.07 6.98 

Lohit -56000.* Max WS 28023 137.60 140.8 7.12 


11-35 

CISMHE


River 

Chainage 

(m) d/s 

of 

Demwe 

Lower 

dam axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

Lohit -56500.* Max WS 28018 137.45 140.51 7.26 


Lohit -57500.* Max WS 28014 137.15 139.84 7.54 

Lohit -58000 Max WS 28012 137.00 139.39 7.68 

Note : .* indicates the cross section locations interpolated by HEC-RAS Model 

11.3.10 Maximum water level in virgin condition of Lohit river due to 

occurrence of PMF 

It is important to know the water level for occurrence of PMF in the virgin 

condition of the Lohit river i.e., without Demwe Lower dam. This will indicate 

inundation levels under virgin conditions. In this condition the PMF has been 

impinged at chainage “0” of the Lohit river (location just downstream of dam) 

without considering the Demwe Lower dam. 


locations of the Lohit river are given in Table 11.7. The average velocity of the 

flood wave in this case is also about 8 km/hour. 

Table 11.7: Maximum discharge, water level and average travel time in virgin 

condition of Lohit river due to occurrence of PMF 

River 

Chainage (m) 

d/s of 

Demwe 

Lower dam 

axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit 0 Max WS 28500 296.37 316.61 0 

Lohit -100 Max WS 28497 294.87 317.04 0 

Lohit -200 Max WS 28496 292.17 317.55 0 


Lohit -400 Max WS 28492 293.57 317.13 0.01 


11-36 

CISMHE


River 

Chainage (m) 

d/s of 

Demwe 

Lower dam 

axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit -600 Max WS 28489 299.27 315.67 0.01 

Lohit -1000 Max WS 28482 291.97 312.04 0.02 

Lohit -1500 Max WS 28486 290.47 310.19 0.04 

Lohit -2000 Max WS 28485 292.27 302.59 0.05 

Lohit -2500.* Max WS 28483 286.14 294.42 0.07 

Lohit -3000 Max WS 28479 280.00 292.14 0.09 

Lohit -3500.* Max WS 28474 278.00 289.96 0.11 

Lohit -4000 Max WS 28465 276.00 286.79 0.14 


Lohit -5000 Max WS 28447 272.00 285.21 0.21 

Lohit -5500.* Max WS 28435 269.50 284.46 0.26 

Lohit -6000 Max WS 28433 267.00 281.65 0.3 

Lohit -6500.* Max WS 28431 265.50 278.86 0.32 

Lohit -7000.* Max WS 28426 264.00 276.08 0.35 

Lohit -7500.* Max WS 28424 262.50 273.31 0.38 

Lohit -8000.* Max WS 28421 261.00 270.48 0.41 

Lohit -8500.* Max WS 28419 259.50 267.74 0.45 


Lohit -9500.* Max WS 28414 256.50 262.17 0.53 

Lohit -10000 Max WS 28413 255.00 258.59 0.57 

Lohit -10500.* Max WS 28410 250.37 253.99 0.6 

Lohit -11000.* Max WS 28410 245.75 249.43 0.63 

Lohit -11500.* Max WS 28407 241.13 244.77 0.67 

Lohit -12000.* Max WS 28406 236.50 240.21 0.7 

Lohit -12500.* Max WS 28404 231.88 235.39 0.73 

Lohit -13000.* Max WS 28404 227.25 230.9 0.77 

Lohit -13500.* Max WS 28402 222.63 225.64 0.8 

Lohit -14000 Max WS 28397 218.00 221.82 0.85 


Lohit -15000.* Max WS 28387 215.38 219.84 0.98 

Lohit -15500.* Max WS 28385 214.06 218.7 1.04 



11-37 

CISMHE


River 

Chainage (m) 

d/s of 

Demwe 

Lower dam 

axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit -16500.* Max WS 28377 211.44 216.31 1.15 

Lohit -17000.* Max WS 28374 210.12 215.09 1.2 

Lohit -17500.* Max WS 28370 208.81 213.86 1.26 

Lohit -18000.* Max WS 28369 207.50 212.62 1.31 

Lohit -18500.* Max WS 28365 206.19 211.38 1.36 

Lohit -19000.* Max WS 28362 204.88 210.14 1.41 

Lohit -19500.* Max WS 28358 203.56 208.89 1.46 

Lohit -20000.* Max WS 28357 202.25 207.64 1.51 

Lohit -20500.* Max WS 28354 200.94 206.38 1.56 

Lohit -21000.* Max WS 28351 199.63 205.13 1.61 

Lohit -21500.* Max WS 28350 198.31 203.9 1.66 

Lohit -22000 Max WS 28348 197.00 202.24 1.71 

Lohit -22500.* Max WS 28346 195.58 200.44 1.75 

Lohit -23000.* Max WS 28345 194.17 198.65 1.79 

Lohit -23500.* Max WS 28343 192.75 196.9 1.84 

Lohit -24000.* Max WS 28342 191.33 195.17 1.88 

Lohit -24500.* Max WS 28340 189.92 193.48 1.93 

Lohit -25000.* Max WS 28339 188.50 191.81 1.97 

Lohit -25500.* Max WS 28337 187.08 190.16 2.02 

Lohit -26000.* Max WS 28336 185.67 188.55 2.07 

Lohit -26500.* Max WS 28334 184.25 186.86 2.13 

Lohit -27000.* Max WS 28332 182.83 185.38 2.19 

Lohit -27500.* Max WS 28331 181.42 183.32 2.25 

Lohit -28000 Max WS 28329 180.00 181.78 2.32 

Lohit -28500.* Max WS 28325 178.50 180.86 2.41 

Lohit -29000.* Max WS 28321 177.00 179.77 2.5 

Lohit -29500.* Max WS 28318 175.50 178.57 2.57 

Lohit -30000.* Max WS 28313 174.00 177.27 2.63 

Lohit -30500.* Max WS 28309 172.50 175.87 2.69 

Lohit -31000.* Max WS 28308 171.00 174.38 2.74 




11-38 

CISMHE


River 

Chainage (m) 

d/s of 

Demwe 

Lower dam 

axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 







Lohit -35500.* Max WS 28295 157.50 162.05 3.16 


Lohit -36500.* Max WS 28292 154.50 159.14 3.25 

Lohit -37000.* Max WS 28291 153.00 157.58 3.3 

Lohit -37500.* Max WS 28287 151.50 156.11 3.34 

Lohit -38000 Max WS 28283 150.00 155.29 3.4 

Lohit -38500.* Max WS 28279 149.50 154.71 3.48 

Lohit -39000.* Max WS 28274 149.00 154.12 3.55 

Lohit -39500.* Max WS 28270 148.50 153.53 3.62 

Lohit -40000.* Max WS 28266 148.00 152.94 3.7 

Lohit -40500.* Max WS 28262 147.50 152.35 3.77 

Lohit -41000.* Max WS 28258 147.00 151.76 3.84 

Lohit -41500.* Max WS 28254 146.50 151.17 3.91 

Lohit -42000.* Max WS 28250 146.00 150.58 3.98 

Lohit -42500.* Max WS 28246 145.50 149.99 4.05 

Lohit -43000.* Max WS 28242 145.00 149.4 4.12 

Lohit -43500.* Max WS 28239 144.50 148.82 4.19 

Lohit -44000.* Max WS 28235 144.00 148.25 4.26 

Lohit -44500.* Max WS 28232 143.50 147.67 4.33 

Lohit -45000.* Max WS 28229 143.00 147.05 4.4 

Lohit -45500.* Max WS 28226 142.50 146.4 4.47 

Lohit -46000.* Max WS 28223 142.00 145.74 4.55 


Lohit -47000.* Max WS 28195 141.00 144.48 4.7 

Lohit -47500.* Max WS 28171 140.50 144.08 4.8 

Lohit -48000 Max WS 28153 140.00 143.89 4.92 


11-39 

CISMHE


River 

Chainage (m) 

d/s of 

Demwe 

Lower dam 

axis 

Profile 

Max 

discharge 

Bed level 

Max. 

Water 

level 

Travel 

Time 

(m3/s) (m) (m) (hrs) 

Lohit -48500.* Max WS 28143 139.85 143.74 5.06 

Lohit -49000.* Max WS 28127 139.70 143.59 5.2 

Lohit -49500.* Max WS 28119 139.55 143.43 5.34 

Lohit -50000.* Max WS 28111 139.40 143.28 5.48 

Lohit -50500.* Max WS 28097 139.25 143.11 5.61 

Lohit -51000.* Max WS 28090 139.10 142.94 5.75 

Lohit -51500.* Max WS 28078 138.95 142.77 5.89 

Lohit -52000.* Max WS 28072 138.80 142.59 6.02 


Lohit -53000.* Max WS 28056 138.50 142.21 6.3 

Lohit -53500.* Max WS 28047 138.35 142 6.43 

Lohit -54000.* Max WS 28043 138.20 141.79 6.57 

Lohit -54500.* Max WS 28036 138.05 141.56 6.71 

Lohit -55000.* Max WS 28032 137.90 141.33 6.84 

Lohit -55500.* Max WS 28026 137.75 141.07 6.98 

Lohit -56000.* Max WS 28023 137.60 140.8 7.12 

Lohit -56500.* Max WS 28018 137.45 140.51 7.26 


Lohit -57500.* Max WS 28014 137.15 139.84 7.54 

Lohit -58000 Max WS 28012 137.00 139.39 7.68 

Note : .* indicates the cross section location interpolated by HEC-RAS Model 

11.3.11 Inundation map 

Taking the maximum water level given in Table 11.4, 11.6 and 11.7 for 

different simulated conditions the inundation map is presented in Figure 

11.13. 

11.3.12 Limitations 

The uncertainties associated with the breach parameters, specially breach 

width, breach depth and breach development time may cause uncertainty in 

flood peak estimation and arrival times. Further the high velocity flows 


11-40 

CISMHE


associated with dam break floods can cause significant scour of channels. 

This enlargement in channel cross section is neglected since the equations for 

sediment transport, sediment continuity, dynamic bed form friction etc. are not 

included among the governing equations of the model. The narrow channels 

with minimal flood plains are subject to over estimation of water elevation due 

to significant channel degradation. The dam breach floods create a large 

amount of transported debris, which may accumulate at very narrow cross 

sections, resulting water level variation at downstream locations. This aspect 

has been neglected due to limitations in modeling of such complicated 

physical process. 

11.4 DISASTER MANAGEMENT PLAN 

From the result it is evident that up to about 58 km d/s of the proposed Lower 

Demwe dam, time required in reaching the flood wave elevation to the 

maximum is of the order of 6.68 hr. It makes it very hard for rescue and 

evacuation. Since the time available is very short, the Disaster Management 

Plan should, therefore, concentrate on preventive actions. 

Surveillance and monitoring programmes are required to be implemented 

during design and investigation, construction, first reservoir filling, early 

operation period and operation & maintenance phases of the life cycle of dam. 

It is desirable that all gates, electricity, public announcement system, power 

generator backups etc are thoroughly checked before arrival of the monsoon. 

As it is clear from the results that u/s water level has significant effect on the 

dam break flood, the following flood conditions may be considered for different 

level of alertness: 

1) If u/s water level reaches at top of the dam, it may be considered as an 

emergency. At this point only a few minutes are available for taking any 

action. All the staff from the dam site should be alerted to move to a safe 

place. The district administration and the corporation’s head office shall be 

informed about the possibility of dam failure. 

2) If u/s water level rises above the dam top and dam begins to fail, it may be 

considered as a disaster condition. At this stage, nothing can be done. 


11-41 

CISMHE


Information in this regard should be given to the head office and district 

administration. 

• If upstream water level is at or below FRL and flood is of the order 

of 20% to 30% of PMF, it may be considered as normal flood 

condition and normal routine may be maintained. 

• If upstream water level is rising above FRL/MWL, it may be 

considered as Level-1 emergency. In this condition at least 11 

gates must be kept fully operational. All concerned officials should 

be alerted so that they may reach at the dam site to take suitable 

actions. Preventive actions may be carried out simultaneously. A 

suitable warning and notification procedure may be laid. The local 

officials should be informed about the situation. 

• If upstream water level reaches at the top of the dam, it may be 

considered as Level-2 emergency. At this point only a few 

minutes are available for taking any action. All the staff from the 

dam site should be alerted to move to a safe place. The district 

level office and the corporation’s head office should be informed 

about the dam overtopping. 

• If upstream water level is rising above the dam top and dam has 

been overtopped. It may be considered as a disaster condition. 

Any information in this regard should be immediately provided to 

civil administration for necessary rescue operations. 

The following measures can be taken to avoid the loss of lives and property: 

1) To establish an effective Dam Safety Surveillance and monitoring 

program including rapid analysis and interpretation of instrumentation 

and observation data; periodic inspection and safety reviews/evaluation 

by an independent panel of experts. 

2) To formulate and implement an Emergency Action Plan to minimize to 

the maximum extent possible, the probable loss of life and damage to 

property in the event of failure of dam. 


11-42 

CISMHE


11.4.1 Surveillance 

The surveillance and monitoring programs are required to be implemented 

during design and investigation, construction, early operation period and 

operation and maintenance phases of the life cycle of the dam. An affective 

flood forecasting system is required by establishing hourly gauge reading at 

suitable upstream locations with real time communication at the top. An 

effective dam safety surveillance, monitoring and observation along with 

periodic inspection, safety reviews and evaluation must be put in place. These 

programs will be implemented in five phases in the life cycle of a dam viz. 

i) design and investigation phase, 

ii) construction phase, 

iii) first reservoir filling, 

iv) early operation period, and 

v) operation and maintenance phase. 

11.4.2 Emergency Action Plan 

An emergency is defined as a condition of serious nature which develops 

unexpectedly and endangers downstream property and human life and 

requires immediate attention. Emergency Action Plan shall include all 

potential indicators of likely failure of the dam, since the primary concern is for 

timely and reliable identification and evaluation of potential emergency. 

This plan presents warning and notification procedures to be followed in case 

of potential failure of the dam. The purpose is to provide timely warning to 

nearby residents and alert key personnel responsible for taking action in case 

of an emergency. 

11.4.3 Administrative and Procedural Aspects 

The Administrative and Procedural Aspects of Emergency Action Plan 

consists of a flowchart depicting the names, addresses and telephone 

numbers of the responsible officials. In order of hierarchy, the following 

system will usually be appropriate. In the event of potential emergency, the 

observer at the site is required to report it to the Head of Project through a 


11-43 

CISMHE


wireless system, if available, or by the fastest communication system 

available. The Head of Project shall be responsible for contacting the Civil 

Administration, viz. Deputy Commissioner. In order to oversee all the 

operations required to tackle the emergency situations, a centralized control 

room would be set up by the project authorities at Tezu/Parasuramkund. 

Each person would be made aware of his/her responsibilities/ duties and the 

importance of work assigned under the Emergency Action Plan. All the 

villages falling under the flood prone zone or on the margins would be 

connected through wireless communication system with backup of standby 

telephone lines. A centralized siren alert system would be installed at all the 

Village Panchayats so that in the event of a warning all villagers can be 

alerted through sirens rather than informing everybody through messengers 

which is not feasible in such emergency situations. 

11.4.4 Preventive Action 

Once the likelihood of an emergency situation is suspected, action has to be 

initiated to prevent a failure. The point at which each situation reaches an 

emergency status shall be specified and at that stage the vigilance and 

surveillance shall be upgraded. At this stage, a thorough inspection of the 

dam shall be carried out to locate any visible signs of distress. 

The anticipated need of equipment shall be evaluated and if these are not 

available at the dam site, the exact locations and availability of these 

equipments shall be identified. A plan shall be drawn on priority for inspection 

of the dam. The dam, its sluices and non-overflow sections will be properly 

illuminated. 

11.4.5 Communication System 

An efficient communication system and a downstream warning system is 

absolutely essential for the success of an emergency plan especially in the 

present case because of inadequacy of time. The difference between a high 

flood and a dam break situation shall be made clear to the downstream 

people. All of the villages falling under the flooding zone or on margins are 


11-44 

CISMHE


required to be connected through wireless system backed by stand-by 

telephone lines. A centralized siren system is to be installed at Panchayats so 

that in event of a warning, all villagers can be alerted, through messengers 

which may not be possible in this case. 

11.4.6 Merits of Satellite Communication System 

Keeping the disaster scenario in mind, any terrestrial system such as land 

lines, etc. is likely to be the first casualty in earthquakes or floods. The 

restoration of such systems is time consuming. Moreover the maintenance of 

such lines becomes a great problem in emergency even for the technical 

personnel who are required to reach the site of fault, which may be struck by 

the disaster. So the system cannot be put back into operation soon. The fault 

repairs and restoration of communication services are usually not possible for 

a considerable period of time after the calamity has struck. Moreover, it is 

critical that the communication systems are restored at the earliest so that 

relief/medical teams and other personnel can be arranged at the earliest 

possible time. All the subsidiary help depends solely on the communication 

system. As this criteria is paramount, existing systems such as telephones 

and telex, etc. are practically of little use in case of such events and situations. 

Similarly, microwave links are expected to be down due to collapse of towers, 

etc. Restoration of towers and alignment of equipment is again a time 

consuming activity. 

Keeping in view the urgency of services and their dependability during 

emergency relevant to the disaster conditions, satellite based systems present 

an ideal solution. The satellite based system usually comprises following 

components. 

i) A small dish of approximately one meter diameter 

ii) Associated radio equipment 

iii) A power source 

The deployment of the system is not dependent on the restoration of land 

routes. The existing satellite based communication systems are designed in 

such a manner that they are able to withstand fairly high degree of demanding 


11-45 

CISMHE


environmental conditions. Secondly, the restoration of the satellite based 

system can be undertaken by carrying maintenance personnel and equipment 

by helicopters at a very short notice. Even the fresh systems could be 

inducted in a matter of an hour or so because most of these are designed for 

transportability by air. The deployment takes usually less than an hour. The 

power requirements are not large and can be met by sources such as 

UPS/batteries/ generators. 

11.4.7 Financial Outlay for Installation of VSAT Communication System 

The cost of deployment and maintenance of a telecommunication system in 

disaster prone areas is not as important as the availability, reliability and quick 

restoration of the system. The cost of both satellite bandwidth and the ground 

components of the satellite communication system has been decreasing 

rapidly like that of V-SAT (Very Small Aperture Terminal) based systems 

supporting a couple of voice and data channels. Some highly superior 

communication systems in VSAT without time delay are marketed by licensed 

service providers/agencies like HECL, HFCL, ESSEL Shyam, Telstra V-Com, 

HCL Comnet, RPG Satellite Communications, etc. There are two different 

types of systems with the above mentioned capabilities available in the market 

viz. TDMA and DAMA. The two alternatives for VSATs are: time designed 

multiple access (TDMA) and demand assigned multiple access (DAMA). In a 

TDMA network, all remote VSATs communicate with the service provider’s 

central hub station. The hub station monitors and controls all VSATs in the 

network and the entire customer traffic is routed through it. On the other hand, 

in the DAMA network, VSATs are pre-allocated a designated frequency. 

Equivalent of the terrestrial leased-line solutions, DAMA solutions use the 

satellite resources constantly. Consequently, there is no call-up delay, which 

makes them most suited for interactive data applications or high-traffic 

volume. Single Channel per Carrier (SCPC refers to the usage of a single 

satellite carrier for carrying a single channel of user traffic. In case of ‘SCPC 

VSATs’, the frequency is allocated on a pre-assigned basis. DAMA network 

uses a pool of satellite channels, which are available for use by any station in 

that network. On demand, a pair of available channels is assigned, such that a 

call can be established. Once the call is completed, channels are returned to 


11-46 

CISMHE


the pool for being assigned to another call. Since the satellite resource is used 

only in proportion to the active circuits and their holding times, it is ideally 

suited for voice traffic and data traffic in batch mode. 

Therefore, SCPC & DAMA has been recommended for the Lower Demwe H.E. 

project. Two such systems would be installed in the upstream catchment of 

Lohit River and four such systems would be installed in the downstream reach. 

The estimated cost of installation of such a communication system has been 

given in Table 11.8. 

11.4.8 Evacuation Plans 

Emergency Action Plan includes evacuation plans and procedures for 

implementation based on local needs. These are: 

• Demarcation/prioritization of areas to be evacuated. 

• Notification procedures and evacuation instructions. 

• Safe routes, transport and traffic control. 

• Shelter areas 

• Functions and responsibilities of members of evacuation team. 

The flood prone zone in the event of break of Lower Demwe dam shall be 

marked properly at the village locations with adequate factor of safety. As the 

flood wave takes some time in reaching these villages, its populace shall be 

informed in time through wireless and sirens etc. so that people may climb on 

hills or to some elevated place beyond the flood zone which has been 

marked. 

The Evacuation Team would comprise of: 

i) D.M./ his Nominated Officer (To peacefully relocate the people to 

places at higher elevation with state administration) 

ii) Head of the Project (Team Leader) 

iii) S.P./Nominated Police Officer (To maintain law and order) 

iv) C.M.O. of the area (To tackle morbidity of affected people) 

v) Sarpanch/ Affected Village Representative to execute the resettlement 

operation with the aid of state machinery and project proponents 

vi) Sub-committees at village level 


11-47 

CISMHE


The Head of Project will be responsible for the entire operation including 

prompt determination of the flood situation from time to time. Once the red 

alert is declared the whole state machinery will come into swing and will start 

evacuating people in the inundation areas delineated in the inundation map. 

For successful execution, annually Demo exercise will be done. DM is to 

monitor the entire operation. 

11.4.9 Notifications 

Notification procedures are an integral part of any emergency action plan. 

Separate procedures shall be established for slowly and rapidly developed 

situations and failure. Notifications will include communications of either an 

alert situation or an alert situation followed by a warning situation. An alert 

situation will indicate that although failure or flooding is not imminent, a more 

serious situation can occur unless conditions improve. A warning situation will 

indicate that flooding is imminent as a result of an impending failure of the 

dam. It will normally include an order for evacuation of delineated inundation 

areas. For a regular watch on the flood level situation, it is necessary that two 

or more people man the flood cell so that an alternative person is available for 

notification round the clock. 

In addition, a few guidelines to be generally followed by the inhabitants of 

flood prone areas, which form part of public awareness for disaster mitigation 

include: 

• Listen to the radio for advance information and advice. 

• Disconnect all electrical appliances and move all valuable personal and 

household goods and all clothing out of reach of flood water. 

• Move vehicles, farm animals and movable goods to the highest ground 

nearby. 

• Move all dangerous pollutants and insecticides out of reach of water. 

• Do not enter flood waters on foot, if it can be avoided. 


11-48 

CISMHE


11.5 Cost Estimates 

The estimated total cost of execution of disaster management plan including 

the equipment would be Rs. 251.88 lakh and it is given in Table 11.8. 

Table 11.8: Estimated cost of setting up of a satellite communication system 

Sl. No. Product Amount (Rs. in lakhs) 

A. Setting up of V-SAT communication system 

1. Product Name : SCPC & DAMA (6 sites) 

@ Rs.18.00 lakhs per site 

108.00 

a) Antenna 1 x 2.4 M 

b) RF 1 x 2 W 

c) Modem 1 x 1No. 

2. Generators 6 Nos. (2 KVA) 9.00 

3. UPS 6 Nos. (2 KVA) 6.00 

Sub-Total (A) 123.00 

4. Installation and maintenance of system, maintenance 

and running cost of UPS, generators, etc. 

@ 12% of the total cost for 3 years (Rs. 10.8 x 3 yrs) 

38.88 

B. Installation of alert systems, 

Setting up of control room, etc. 

30.00 

C. Notification and publication procedures, 

miscellaneous, etc. 

20.00 

D. Setting up Seismic Observatory 40.00 

Total (A+B+C) 251.88 


11-49 

CISMHE


Figure 11.9: Time series of water level for the entire simulation period due to Demwe 

Lower dam break 

(Note1: The date and time (hour) shown on horizontal axis of the plots are the relative dates 

and time as used in the HEC-RAS Model set up) 

(Note 2: LOHIT DEMWE-DS -28000 denote the Lohit river cross section 28000 m d/s of 

Demwe Lower dam axis. The same way all other notations may please be read) 

STAGE (METERS) 


325 

320 

315 

310 

305 



300 

2400 1200 2400 1200 2400 1200 2400 1200 2400 

20Sep2008 21Sep2008 22Sep2008 

Tim e 

23Sep2008 

182.5 

182.0 

181.5 

181.0 

180.5 

LOHIT DEMWE-DS -28000 


180.0 

2400 1200 2400 1200 2400 1200 2400 1200 2400 

20Sep2008 21Sep2008 22Sep2008 

Tim e 

23Sep2008 


11-50 

CISMHE



140.0 

139.5 

139.0 

138.5 

138.0 

137.5 



137.0 

2400 1200 2400 1200 2400 1200 2400 1200 2400 

20Sep2008 21Sep2008 22Sep2008 

Tim e 

23Sep2008 

Figure 11.10: Time series for the peak segment of water level at different 

cross sections of Lohit river due to Demwe Lower dam break 

(Note: The notation LOHIT DEMWE DS -1000 denotes river cross section located 1000m 

downstream of dam axis. The same way all other notations may please be read. 


324 

322 

320 

318 

316 

314 

312 

310 

308 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




11-51 

CISMHE





315 

310 

305 

300 

295 

290 

296 

294 

292 

290 

288 

286 

284 

289 

288 

287 

286 

285 

284 

283 

282 

281 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 



LOHIT DEMWE-DS -2500.* 

Legend 




Legend 




11-52 

CISMHE





286 

284 

282 

280 

278 

276 

274 

272 

276 

274 

272 

270 

268 

266 

266 

264 

262 

260 

258 

256 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-53 

CISMHE




256 

254 

252 

250 

248 

246 

244 

242 

240 

238 

236 

234 

232 

230 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




11-54 

CISMHE





227 

226 

225 

224 

223 

222 

221 

220 

221 

220 

219 

218 

217 


218 

217 


215 

214 

213 

212 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 



LOHIT DEMWE-DS -16000.* 

Legend 

LOHIT DEMWE-DS -16500.* 



11-55 

CISMHE




214 

213 

212 

211 

210 

209 

211 

210 

209 

208 

207 

206 

205 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




11-56 

CISMHE





202 

201 

200 

199 

198 

197 

196 

197 

196 

195 

194 

193 

192 

191 

192 

191 

190 

189 

188 

187 

186 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-57 

CISMHE





187 

186 

185 

184 

183 

182 

181 

181.5 

181.0 

180.5 

180.0 

179.5 

179.0 

178.5 

178.0 

179 

178 

177 

176 

175 

174 

173 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-58 

CISMHE





175 

174 

173 

172 

171 

170 

169 

171 

170 














0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-59 

CISMHE








159 

158 

157 

156 

157.5 

157.0 

156.5 

156.0 

155.5 

155.0 

154.5 

154.0 

155.5 

155.0 

154.5 

154.0 

153.5 

153.0 

152.5 

152.0 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-60 

CISMHE




153.5 

153.0 

152.5 

152.0 

151.5 

151.0 

150.5 

150.0 

152.0 

151.5 

151.0 

150.5 

150.0 

149.5 

149.0 

148.5 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




11-61 

CISMHE





150.0 

149.5 

149.0 

148.5 

148.0 

147.5 

147.0 

146.5 

148.0 

147.5 

147.0 

146.5 

146.0 

145.5 

145.0 

146.0 

145.5 

145.0 

144.5 

144.0 

143.5 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-62 

CISMHE





144.8 

144.6 

144.4 

144.2 

144.0 

143.8 

143.6 

143.4 

143.2 

144.2 

144.0 

143.8 

143.6 

143.4 

143.2 

143.0 

142.8 

142.6 

143.8 

143.6 

143.4 

143.2 

143.0 

142.8 

142.6 

142.4 

142.2 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-63 

CISMHE





143.2 

143.0 

142.8 

142.6 

142.4 

142.2 

142.0 

141.8 

141.6 

142.4 

142.2 

142.0 

141.8 

141.6 

141.4 

141.2 

141.0 

141.4 

141.2 

141.0 

140.8 

140.6 

140.4 

140.2 

140.0 

139.8 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 




Legend 




Legend 




11-64 

CISMHE



140.2 

140.0 

139.8 

139.6 

139.4 

139.2 


0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400 

22Sep2008 

Tim e 


Legend 



11-65 

CISMHE


Elevation (m) 

Elevation (m) 

Figure 11.11: Plots of Lohit river cross sections used in HEC-RAS set up 

550 

500 

450 

400 

350 

300 

Demwe Lower 

River = Lohit Reach = Demwe-ds RS = 0 c/s at Demwe Lower dam axis 

250 

0 100 200 300 400 500 600 

Elevation (m) 

550 

500 

450 

400 

350 

300 

550 

500 

450 

400 

350 

300 

.04 

Max. water level due to dam break flood 

Station (m) 

250 

0 100 200 300 400 500 600 

Legend 

WS Max WS 

Ground 

Bank Sta 

Demwe Lower 

River = Lohit Reach = Demw e-ds RS = -100 100 m d/s of Demw e Low er dam axis 

.04 

Station (m) 

Demwe Lower 


250 

0 100 200 300 400 500 600 700 

Station (m) 


.04 

Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

11-66 

CISMHE


Note: RS = -300 denotes river cross section 300 m d/s of dam axis. The same way all other 

locations may please be read. 0.04 is the Manning’s roughness coefficient used for the study 

reach. 

Elevation (m) 

Elevation (m) 

550 

500 

450 

400 

350 

300 

Demwe Lower 


250 

0 200 400 600 800 1000 

550 

500 

450 

400 

350 

300 

.04 

Station (m) 

Demwe Lower 


250 

0 200 400 600 800 1000 

Station (m) 


.04 

Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

11-67 

CISMHE


Elevation (m) 

Elevation (m) 

Elevation (m) 

550 

500 

450 

400 

350 

300 

Demwe Lower 


250 

0 200 400 600 800 1000 1200 1400 

550 

500 

450 

400 

350 

300 

.04 

Station (m) 

250 

0 200 400 600 800 1000 

550 

500 

450 

400 

350 

300 

Demwe Lower 


.04 

Station (m) 

Demwe Lower 


250 

0 200 400 600 800 1000 

Station (m) 


.04 

Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

11-68 

CISMHE


Elevation (m) 

Elevation (m) 

Elevation (m) 

350 

340 

330 

320 

310 

300 

Demwe Lower 


290 

0 200 400 600 800 1000 

500 

450 

400 

350 

300 

.04 

Station (m) 

250 

0 1000 2000 3000 4000 

500 

450 

400 

350 

300 

Demw e Low er Plan: Plan 03 


.04 

Station (m) 



250 

0 1000 2000 3000 4000 5000 6000 

Station (m) 


.04 

Legend 

WS Max WS 

Ground 

Bank Sta 

Le gend 

WS Max WS 

Ground 

Bank Sta 

Le gend 

WS Max WS 

Ground 

Bank Sta 

11-69 

CISMHE


Elevation (m) 

Elevation (m) 

Elevation (m) 

500 

450 

400 

350 

300 



.04 

250 

0 5000 10000 15000 20000 

450 

400 

350 

300 

Station (m) 

250 

0 5000 10000 15000 20000 

Le gend 

WS Max WS 

Ground 

Bank Sta 



.04 

500 

Le gend 

500 

450 

400 

350 

300 

Station (m) 

250 

0 5000 10000 15000 20000 

Station (m) 

25000 30000 35000 40000 

WS Max WS 

Ground 

Bank Sta 


Riv er = Lohit Reach = Demwe-ds RS = -10000 10000 m d/s of Demwe Lower dam axis 

.035 

Legend 


WS Max WS 

Ground 

Bank Sta 

11-70 

CISMHE


Elevation (m) 

Elevation (m) 

Elevation (m) 

550 

500 

450 

400 

350 

300 

250 



200 

0 10000 20000 30000 40000 

500 

450 

400 

350 

300 

250 

200 

.035 

Station (m) 

150 

0 10000 20000 30000 40000 50000 

500 

450 

400 

350 

300 

250 

200 



.035 

Station (m) 



150 

0 10000 20000 30000 40000 

Station (m) 


.035 

Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

11-71 

CISMHE


Elevation (m) 

Elevation (m) 

400 

350 

300 

250 

200 



150 

0 5000 10000 15000 20000 25000 30000 35000 40000 

180 

170 


150 

.035 

Station (m) 


Riv er = Lohit Reach = Demwe-ds RS = -48000 

.035 

140 

0 5000 10000 15000 

Station (m) 

20000 25000 30000 


Legend 

WS Max WS 

Ground 

Bank Sta 

Legend 

WS Max WS 

Ground 

Bank Sta 

11-72 

CISMHE


Elevation (m) 


155 

150 

145 

140 


Riv er = Lohit Reach = Demwe-ds RS = -58000 

.035 

135 

0 5000 10000 15000 20000 25000 30000 35000 40000 

Station (m) 


Legend 

WS Max WS 

Ground 

Bank Sta 

11-73 

CISMHE


Elevation (m) 

330 

320 

310 

300 

290 

280 

270 

260 

250 

240 

230 

220 

210 

200 

190 

180 

170 


150 

140 

130 

120 

110 

100 

Demwe Lower 

Lohit Demwe-ds 

CISMHE 

-58000 

-57000.* 

-56000.* 

-55000.* 

-54000.* 

-53000.* 

-52000.* 

-51000.* 

-50000.* 

-49000.* 

-48000 

-47000.* 

-46000.* 

-45000.* 

-44000.* 

-43000.* 

-42000.* 

-41000.* 

-40000.* 

-39000.* 

-38000 

-37000.* 

-36000.* 

-35000.* 

-34000.* 

-33000.* 

-32000.* 

-31000.* 

-30000.* 

-29000.* 

-28000 

-27000.* 

-26000.* 

-25000.* 

-24000.* 

-23000.* 

-22000 

-21000.* 

-20000.* 

-19000.* 

-18000.* (18000 m d/s of dam axis) 

-17000.* 

-16000.* 

-15000.* 

-14000 

-13000.* 

-12000.* 

-11000.* 

-10000 

-9000.* 

-8000.* 

-7000.* 

-6000 

-5000 

-4000 

-3000 (3000 m d/s of dam axis) 

-2000 

-1000 

-200 

0 10000 20000 30000 40000 50000 60000 

Main Channel Distance (m) 

Figure 11.12: Bed profile, and maximum water surface Profile of Lohit river during Demwe Lower dam break 


Legend 

WS Max WS 

Ground 

11-75



11-76 

CISMHE


CISMHE 

12 

COMPENSATORY AFFORESTATION SCHEME 


The Forest Department of Arunachal Pradesh is responsible for Conservation 

and Management of forest in the State including project area. The basic objective 

of the proposed scheme for Compensatory afforestation is to make up loss of 

forest land proposed to be utilized for construction of Demwe Lower HE project. 

The other objectives shall include: combating soil erosion, afforestation and last 

but not the least maintaining and/or improving ecological and environmental 

balance. 

12.2 EXISTING FOREST AND IMPACT DUE TO PROPOSED PROJECT 

The total land requirement for the proposed project is 1589.97 ha. The forest in 

the project affected areas (the area, which will be actually acquired for the 

project), is under stress due to multiple reasons, the human settlements, 

agriculture activities and grazing in forest areas contribute to the degradation of 

forest. No rare or endangered species are found in the forest area to be diverted 

for the project purpose. There is no significant species diversity found in the 

project affected forest areas. In the construction of dam, clearing of vegetation in 

the submergence area, movement of earth and rock, widening of roads, stocking 

of construction materials, erection of temporary labour sheds and excavation 

activities disturbs the natural vegetation and forest areas. During reservoir 

formation, inundation of the river and associated wetland may occur and some 

species might be lost. However, in the present project area, since the species 

diversity and density being low, loss in biodiversity is not much significant. Trees 

and other vegetation shall be cleared from the reservoir area to avoid low oxygen 

levels due to decomposition in the profoundal zones. Low oxygen level causes 

growth of anoxic species in the reservoir. 

Environmental Management Plan – Compensatory Afforestation Scheme 

12-1


12.3 COMPENSATORY AFFORESTATION 

The Indian Forest Conservation Act (1980) stipulates that: 

� If non-forest land is not available, Compensatory Afforestation is to be done 

on degraded forest land, which must be twice of the forest area affected or 

lost, and 

� If non-forest land is available, Compensatory Afforestation is to be raised 

over an area equivalent to the forest area affected or lost. 

In view of the mandatory provisions of the law, it is required to prepare an 

appropriate management plan for compensatory afforestation scheme for the 

forest land that is likely to be diverted in case of Demwe Lower HEP. As 

presented earlier, the total land required for Demwe Lower HEP is 1590 ha out of 

which around 1409 ha belongs to surface forest area 

(Community/Reserved/Unclassified State Forest). 

Considering the non-availability of non-forest land for undertaking plantation, 

degraded forest land has been selected for this purpose. Therefore, 

Compensatory Afforestation shall be carried out over twice of the surface forest 

land involved in the project i.e. 1409 x 2 = 2818 ha. The compensatory 

afforestation plan has to be systematically implemented along with other soil 

conservation measures and with barbed wire fencing i.e. protection measures to 

mitigate biotic interference. The species to be planted would be area specific; to 

meet the basic needs of the people with respect to fuel wood, fodder, and timber 

with an objective of ecological conservation. 

12.4 SITES FOR COMPENSATORY AFFORESTATION 

The Compensatory Afforestation scheme is proposed to be undertaken on 

degraded forest land identified in consultation with the State Forest Department. 

Compensatory Afforestation will be raised over an area of 2818 ha of degraded 

forestland selected by State Forest Department. 


CISMHE 

12-2


12.5 METHODOLOGY AND COMPONENTS 

The Compensatory Afforestation scheme would be implemented as per 

Integrated Afforestation Programme by the State Forest Department. This 

includes activities like soil conservation works, fencing, protection, awareness, 

monitoring and evaluation along with maintenance for 10 years of period and 

protection of the surrounding forests in the project area. In the hills, trees and 

vegetation cover have an important role for the conservation of soil and ecology. 

Demand of fuel wood, fodder and grazing pressure in the project area adds to 

the loss of forests due to project development. It is very essential to create more 

resources for fuel wood to check further degradation in the area where most of 

the human and livestock population stays. This shall provide vegetal cover to 

barren slopes to check soil erosion and cater to the increasing demand of fuel 

wood and fodder. Soil working and plantation along contours conserves soil and 

enhances moisture regime and adverse effects of surface run-off is reduced 

considerably. Trenches, pits and plants along contour reduce velocity of water, 

increase moisture and seepage of water in soil and reduce loss resulting in better 

growth of plants. Hence soil working and plantation shall be strictly followed 

along the contours. In afforestation areas for digging trenches and pits along the 

contours, it is necessary to first align contour lines with the contour template. 

Trenches should be dug along the contour lines aligned with the help of contour 

template and limestone powder. Generally, 20 to 30 m long trenches are dug 

leaving a space of 50 cm (septa) between two consecutive trenches. Soil is dug 

along the contour lines marked on ground by limestone powder. The dug up soil 

is collected on lower side of the trench and after removing pebbles and weeds, 

the trench is half refilled with soil and berm is made using remaining soil on lower 

trench. On the berm, seed sowing of shrubs or hedges should be done to raise 

vegetative barrier. The size of trench should be 30 cm x 20 cm. The contour 

trenches shall be at an interval of 5 m. For digging 1600 pits per ha pits are dug 

15 cm uphill from the contour trenches. The spacing of pits along contour 

trenches should not be closer than 1.25 m. It is important that the filling of 

trenches should not be left to be done along with plantation during rains to avoid 


CISMHE 

12-3


soil wash. Extreme care should be taken in transporting plants to avoid any 

damage. Plantation should be done well in time during rains and few species that 

get leafless in winter can be planted during winter rains. Seeds of hedge like 

Dodonea, Duranta, Spirea, etc. may be sown in contour terraces before onset of 

monsoon. With a view to conserve soil and water, it is very important to raise the 

vegetative barrier of hedge plants. When surface run-off reaches the line of 

hedges its speed is checked and silt is stopped and only percolated water 

passes down slowly. In the silt left behind, hedges spreads to grow and thus 

making a natural terrace. The plants in the pits near contour trenches get more 

moisture and grow fast. Raising vegetative barrier of hedges has been found 

very useful not only for soil and water conservation but also for fuel wood 

production. 

12.5.1 SEEDLING REQUIREMENTS 

The seedlings to meet the nursery requirements are to be obtained from local 

market supplemented by saplings of Forest Department and new nurseries 

developed under this project in the area. 

12.5.2 Plantation Guard and Protection from fire 

Protection of plantation is greatest challenge as villagers and their cattle may 

damage the plantations before they are established. Hence protection of 

plantation is of paramount importance and guards should be arranged for two to 

three years. Most of the plants shall be guarded against fire, mainly in the 

summer season. 

12.5.3 Species for Compensatory Afforestation 

The species for plantation are selected after considering altitude, aspect, biotic 

pressure, soil depth, moisture etc. There is great pressure of cattle grazing hence 

in plantations, non-fodder fuel wood species should be planted in suitable 

proportion with fodder and timber species. 


CISMHE 

12-4


12.6 INSTITUTIONAL MECHANISM 

12.6.1 Responsibility of various institutions 

The Forest department shall implement the Compensatory Afforestation scheme. 

The project officer of Demwe Lower HEP would liaison with the forest officials as 

for the financial disbursement is concerned. The afforestation program would 

evolve employment opportunities, thus people’s participation should be 

encouraged and would involve mobilization of manpower for plantation activity. 

Secondly development and maintenance of the nursery would be required, for 

which a staffing pattern has been delineated. 

12.6.2 Project Implementation, Monitoring and Reporting Procedure 

Meetings may be held every three months to resolve logistic problems in scheme 

implementation. The Environmental Manager with team members would meet 

with forest officials to ensure the implementation of project on time to time. 

The actual quantities and total provision will be finalized by the forest department 

during the process of forest application. However a tentative financial provision of 

around Rs. 40.00 crore has been made for Compensatory Afforestation for 

Demwe Lower HEP. The total time period for implementation of Compensatory 

Afforestation is 10 years out of which six years of time period will be required for 

raising of plantation and maintenance of plantation will be done for next four 

years. The Compensatory Afforestation will be done by State Forest Department. 

This Compensatory Afforestation scheme has to be approved by competent 

authority during Forest Clearance process. 

12.7 SALIENT REMARKS AND RECOMMENDATIONS 

Salient recommendations for smooth implementation of the compensatory 

afforestation scheme are delineated below: 

• Selection of species having faster growth, and helpful in Soil and Water 

conservation. 

• Sub-contracting of afforestation to local people should be encouraged. 


CISMHE 

12-5


• Project authorities should ensure frequent meetings with the forest 

department and executing teams to enable smooth implementation of the 

Scheme and financial ensure flow. 


CISMHE 

12-6


CISMHE 

13 

RESERVOIR RIM TREATMENT PLAN 


Demwe Lower Hydroelectric Project envisages construction of about 163.0m high 

concrete gravity dam across river Lohit. Considering the reservoir FRL at EL. 

424.8m, the total reservoir area is 1131 hectare. The Reservoir Length along the 

Lohit river is about 23 km. (Plate 13.1). Geological mapping of the reservoir area 

has been carried out on 1 : 10,000 scale (refer Plate 13.2) by taking traverses in 

the approachable area of the reservoir and for the inaccessible portions by 

extrapolating existing geological information collected from GSI and published 

literatures. Lack of proper access and a thick canopy of vegetation & steep terrain 

have been major constraints while conducting the geological mapping of the 

Reservoir area. 

The access to the reservoir area of Lohit is very poor due to its remoteness, lack of 

human settlement, rugged topography, dense vegetation & lack of access road / 

path. The reservoir area is accessible at places only through the National Highway 

located on the right bank of the Lohit river, however, the left bank can be 

approached during non-monsoon period upto 4 km upstream of dam site by 

crossing the river with the help of rubber boat. A traverse was taken upstream of 

the dam axis along the river, using the rubber boat upto the confluence of Lang and 

Lohit Rivers, beyond which due to the presence of rapids it was not possible to 

negotiate. 

13.2 RIVER BASIN CHARACTERISTICS 

Lohit River is amongst the three important Rivers that constitute Brahmaputra 

River; the other two being Dibang and Siang. Lohit River after traversing from Tibet 

and crossing the State of Arunachal Pradesh meets Dibang near Sadia from where 

the combined flow meets Siang after which the River is called Brahmaputra in the 

Environmental Management Plan – Reservoir Rim Treatment Plan 

13-1


plains of Assam. The Lohit basin lies between Latitude 27° 34' N and 29° 36' N 

and Longitude 95° 38' E and 97° 44' E. The snowy mountains in the upper 

catchment, dense evergreen forests in the lower hills, innumerable rivers and 

rivulets are major topographical characteristics of the Lohit basin. The proposed 

dam site lies at Latitude 27° 52’ 48’’ N and Longitude 96° 22’ 39” E. The catchment 

area of the river up to the proposed dam site of Demwe Lower is 20,174 sq. km. 

The Lohit River along with its turbulent tributaries (Kamlang, Tidding, Lang, Balijan, 

CISMHE 

and Kundli) flows through rugged hills with deep gorges flanked with steep valleys. 

The hill ranges trend almost NW-SE & the mountain slopes are usually steep. The 

Lohit River and its major tributaries primarily appear to be glacial valleys 

superimposed & modified by fluvial action. The drainage pattern of the area in 

general is sub parallel to dendretic and is mainly controlled by structural features 

such as joints, fractures, folds, minor & major faults, and lineament etc. Therefore, 

river Lohit flows mainly through major & narrow structural valleys bounded by steep 

slopes. River channels are turbulent, waterfalls and rapids are common. 

Geomorphologically the project area may be subdivided in to two categories, such 

as, Flood Plain and Mountainous range. About 1.5km downstream of the dam axis 

the Lohit river debouches in to the floodplain, characterized by the braided nature 

of the river. In this reach the river changes its course frequently and forms several 

distributaries having meandering course. Due to the frequent shifting of river 

course, several oxbow lakes have formed in the flood plain of the Lohit river. 

Upstream of the Parasuramkund bridge the river is flanked by steeply rising 

mountainous terrain constituting Mishmi Hills. Mishmi Hills forms the outer or the 

southernmost hill ranges in the Lohit basin, abruptly rising from the Lohit flood plain 

and extending beyond the reservoir area of the Demwe Hydroelectric Project. 

These are made up of metasediments- the Lohit Complex of Precambrian age with 

younger mafic and acidic intrusive. The mountain ranges attain elevations of 

between 500m and 3000 m and drained by the tributaries of the Lohit river. 

13.3 GEOLOGY OF THE RESERVOIR AREA 

Geology of the reservoir area has been described in details in baseline data under 

Chapter 6 of EIA report in terms of overburden and bedrock geology. 


13-2


13.4 RESERVOIR STABILITY ANALYSIS 

Major part of the reservoir area of Demwe Lower Hydroelectric Project falls in 

highly rugged and inaccessible terrain. To carryout the reservoir stability analysis 

CARTOSAT 1 stereo image and derivation of slope parameters from 1:10,000 

scale contour map for slope stability analysis was carried out. Various types of 

landslides, viz., active, dormant and stabilized were delineated and studied in detail 

on ground. The digital data was studied using state of the art softwares, viz., 

ERDAS and ArcGIS. The input data, data preparation and methodology for carrying 

out the reservoir stability analysis are described in the following pages. 

13.4.1 Input data 

1. Digital contour maps of project area 1:10.000 scale and 10m contour interval 

2. Cartosat1 stereo data 

3. LISS 3 Multispectral Image 

4. Scanned contour map of 1:15,000 scale 

13.4.2 Data Preparation 

I) Georeferencing of 27 scanned contour maps of 1:15,000 scale in ArcGIS. 

II) Import of 1:10,000 scale contour map from AutoCAD format to ESRI shapefiles, 

cleaning of the data and georeferencing based on feature mapping from 

1:15,000 maps as the supplied data did not have coordinate values. This was a 

very challenging work and consumed lots of time. 

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13.4.3 Methodology 

The basic objective of the work was to map the landslides and categorize them 

based on their state of activity. This was possible to achieve by visual interpretation 

of high resolution CARTOSAT1 data either monoscopically or stereoscopically. 

Stereo model is preferred here because it allows picking up the geometry of 

landslides with much ease and accuracy, depending on the size of the landslides 

and contrast of the image. But to create stereo model very accurate Digital 

elevation Model (DEM) is very essential. Though DEM can be generated from 


13-3


cartosat stereo image automatically but the height accuracy of this DEM is beyond 

acceptable limits (in the order of 100s of m) for the purpose of present project DEM 

is used for orthorectification of the image therefore location accuracy is also a 

concern. To refine the automatically generated DEM some very precise ground 

control points (GCPs) were taken with the help of Differential Global Positioning 

System (DGPS) and GCPs. The GCPs locations on the ground were selected 

keeping in mind that these points can be identified in the Cartosat 1 image. To 

have more accuracy, besides the points taken with the help of GCPs, the objective 

of refining the automatically generated DEM was achieved in following steps. 

Step1 Orthorectification of cartosat image using automatically generated DEM 

Step2 Refinement of the orthorectified image generated in the first step by 

coregistering it with the raster image of 1:15,000 contour maps. 

Step3 The resulting orthorectified cartosat image was then subsetted as per the 

extent of the available 1:10,000 contour map 

Step4 Generation of accurate DEM for area of interest using supplied 1:10,000 

contour data as mass point and drainage and area of extent as break lines. 

Step5 Further refinement of the subsetted image with respect to the DEM created 

from 1:10,000 scale contour map. This DEM has been referred as 10K DEM in the 

subsequent part of the report. 

Step6 Simulation of stereo-view for area of interest was done using the cartosat 

and 10K DEM for mapping of landslides and further analysis. 

Following above steps, two sets of products were generated. 

a. Synoptic view of the regional terrain and landslide distribution using cartosat1 

image and automatically generated DEM. 

b. Detailed analysis of slope parameters and landslide inventory of smaller area 

(area of interest) by refining the products with 10K DEM. 

13.5 LANDSLIDE INVENTORY MAPPING 

Landslides were interpreted and mapped in stereo view (anaglyph) created from 

Cartosat Image and Digital elevation Model (DEM). Red and blue glass was used 


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13-4


for the stereo view. Another product merging IRS LISS 3 multispectral image with 

B&W cartosat image was also generated to aid the interpretation. The following 

rules for interpretation of the landslides were used. 

Key Rule Contents 

Tone Bright white, grayish white 

Vegetation Presence or absence of vegetation, pattern and density of vegetation, 

Location In the vicinity of ridge lines, road sides, and the cut-off side of a river channel 

Shape cumulated as tree-shaped in river basins, or a triangular or rectangular-shape if 

Criterion located near river banks 

Direction The longitudinal axis is in the direction of gravity or perpendicular to flow-lines 

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Based on the above rules the landslides were detected and mapped. A total 

number of thirty landslides (ID nos. 1 to 30) were delineated The anaglyph 

prepared using 10K DEM along with location and ID number of landslides are 

shown in Plate 13.2 and the corresponding analytical data related to individual 

landslides are shown in Table-1. From the distribution of landslides shown in Plate 

13.2 and Table 13.1 it is evident that majority of landslides are in the stretch 

between the confluence of Tidding and Lang with the Lohit river (refer Plate 13.2). 

After delineating the landslides the base and top of each landslide were extracted 

from the 10 K DEM. Delineation of top and base of landslides allowed selecting 

those landslides which are crucial for the stability of the reservoir area. The FRL of 

Demwe Lower Hydroelectric Project is EL 424.8 m and MDDL is kept at EL 408 m, 

therefore the proposed drawdown will be 16.8 m. Besides, the reservoir is 

proposed to be drawn down to EL 365m twice in a year to flush out the sediments 

accumulated. An attempt was made to select the landslides located in between 

365 m to 424.8 m as these landslides may get reactivated due to the drawdown 

(59.8 m). Landslides with ID nos.1, 3, 5, 8, 9, 10, 19 and 25 satisfy these criteria 

(refer Plate – 13.3). 


13-5


Table 13.1: Data pertaining to landslides shown in Plate – 13.2 

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Slide ID Type Activity Area (sq. m) Level of Base (m) Level of Crown (m) 

1 slide scar dormant 44678.84 397.80 600.00 

2 debris slide dormant 18268.44 599.81 600.00 


4 shallow debris slide/scree active 12904.71 491.49 600.00 




8 Slide scar dormant 13396.58 400.00 591.94 

9 debris slide active 8986.09 341.15 490.85 







16 shallow debris slide/scree Dormant 3344.07 600.00 600.00 





21 debris slide active 16162.16 560.26 600.00 




25 slide scar stabilised 33225.61 400.00 600.00 



28 debris slide active 1160.63 474.84 507.51 



*The Crown level for these slides may be more that 600 m but the highest contour on 1:10,000 topographic 

map is 600 m and the same number is indicated in the table. 


13-6


13.5.1 Field Checks 

After preparing the landslide inventory map and locating the landslides (ID nos. 1, 

3, 5, 8, 9, 10, 19 and 25) field traverses were taken to check these landslides on 

ground to ascertain the geotechnical parameters responsible for the mass failure 

and their remedial measures. During the course of field checks, it was found that 

out of the eight critical landslides (ID nos. 1, 3, 5, 8, 9, 10, 19 and 25), three (ID 

nos. 9, 10 & 19) are not landslides but near vertical scarps characterized by light 

tone and no vegetation. At the same time, one active landslide (ID no. 31) 

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occurring about 600m upstream of the dam axis could not be identified during 

landslide inventory using cartosat 1 data due to the shadow zone. Therefore, from 

the point of view of reservoir rim stability six landslides (ID nos. 1, 3, 5, 8, 25 & 31) 

will be critical (refer Plate 13.2), the detail of which are given in table 13.2 below. 

Table 13.2: Data pertaining to landslides between 408 to 424.8 m 

Slide 

Type Activity Area (sq. Level of Base Level of Crown 

ID 

m) 

(m) 

(m) 

1 Slide scar Dormant 44678.84 397.80 >=600* 

3 Debris slide Dormant 11865.27 393.91 482.72 

5 

Shallow debris slide/ 

scree 

Active 12759.75 389.90 >=600* 

8 Slide scar Dormant 21077.51 400.00 591.94 

25 Slide scar Dormant 33225.61 400.00 >=600* 

31 Slide scar Active 5997.43 390.00 540.00 

*The Crown level for these slides may be more that 600 m but the highest contour on 1:10,000 topographic 

map is 600 m and the same number is indicated in the table. 

13.5.2 Relationship of landslides with Geotechnical parameters 

An attempt was made to correlate the landslide occurrences with the lithological 

units and general foliation trends. The area in between the confluence of Lohit & 

Lang, and Lohit & Tidding is largely composed of schistose rocks and general trend 

of foliation is NW-SE with gentle to moderate dip in the NE. It is a known fact that 

such rocks are prone to debris slides of different magnitude and size depending on 

slope of the terrain. Majority of landslides mapped in the Cartosat 1 image are 

located either on the eastern & north-eastern slopes or western & south-west 


13-7


slopes exposing schistosed rocks, and the magnitude of landslides increases if the 

slope failure is in carbonaceous graphite schist. 

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A few landslides have been noticed within predominantly gneissic terrain, but the 

major cause of failure in most of the cases has resulted due to the undercut action 

of the river giving rise to planar failure along the valley dipping joints. Due to the 

planar failure, only landslide scars are visible and there is no distress noticed within 

the slip surface. The rockmass around the scar appears to be stable (Figure 13.1). 

Once the reservoir is filled up, the intensity of toe cutting action of the river will get 

reduced to zero, thus eliminating the possibility of planar failure due to river action. 

Besides, landslides in the area have resulted due to the cumulative effect of 

various sets of discontinuities and shear zones. 

Figure 13.1: Landslide scar resulted by the planar failure along the valley dipping 

joints. Loc: 400m downstream of the dam axis 

A brief account of the critical landslides (ID nos. 1, 3, 5, 8, 25 & 31) occurring in the 

reservoir rim area and the remedial measures to stabilize them particularly in 

between EL 408m and EL 424.8m Elevations are given below. 


13-8


13.5.2.1 Landslide – 1 

It is a slide scar with its toe at EL 397.80 m and crown extending beyond EL 600 m 

CISMHE 

is located on the right bank of the Lohit river, about 2 km downstream of the 

confluence of the Lohit and Tidding rivers. The slide scar is located over graphite 

schist and has resulted due to the planar failure triggered by the undercutting 

action of the river. The scar face is fresh and there is no distress noticed within the 

slip surface. The rockmass around the scar appears to be stable. Once the 

reservoir is filled up, the intensity of toe cutting action of the river will get 

appreciably reduced, therefore eliminating initiation of planar failure due to river 

action. 

13.5.2.2 Landslide – 3 

It is located on the right bank about 1.5 km downstream of the confluence of the 

Lohit and Tidding rivers. It is an old and dormant slide with its toe at EL 393.91 m 

and crown at EL 482.72 m, resulted by the failure of a gently sloping debris 

accumulation, resulted by the undercutting action of the river. The slide in its major 

part is sparsely vegetated and stabilized at present, and the debris comprises 

admixture of big rock blocks and smaller rock fragments of quartzite. In between 

FRL (EL 424.8m) and Maximum Drawdown Level (EL 408m) the debris 

accumulation due to its open framework will not be subjected to pore pressure 

fluctuations, therefore will remain more or less stable. No specific remedial 

measure is required for this already stabilized landslide. 

13.5.2.3 Landslide – 5 

It is located about 2.5 km downstream of the confluence of the Lohit and Tidding 

rivers, on the left bank. It is an active slide with its toe at EL 389.90 m and crown 

extending beyond EL 600m, resulted by the failure of the shallow debris /scree 

accumulation deposited on steeply sloping hill slope. Debris comprises admixture 

of rock fragments of chlorite schist / quartzite and fine silt and sand fraction. 

Remedial Measures: 


13-9


Field studies revealed that the failure of the unconsolidated slope wash material 

has been initiated by the erosion in its terminal parts by an ephemeral stream. To 

contain further sliding, shotcreting up to FRL (EL 424.8m) may be carried out, and 

a toe wall at the bottom may be constructed. To stabilize the debris accumulation 

above the FRL, a toe wall with drainage holes may be constructed above the FRL. 

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Even after providing toe wall and shotcrete of adequate thickness, the 

unconsolidated, permeable mass behind will get charged with water, which will 

increase the pore pressure. During the operation of powerhouse and more 

particularly during the flushing of reservoir, once the water level goes down the 

pore pressure will decrease and the debris accumulation may become unstable. 

Adequate measures, such as, weep holes/ drainage holes etc are to be provided 

so that the water charged mass behind remains stable. Three geological cross 

sections were prepared (refer Plates 13.4a, b & c) along the longer section of the 

slide, and the proposed protection measures have been shown to stabilize the 

zone during draw down. 

13.5.2.4 Landslide – 8 & 25 

These two dormant landslides are located on the left bank, at about 300m and 

400m downstream of the confluence of the Lohit and Tidding rivers respectively. In 

both the cases failure of the rock mass has resulted due to the undercut action of 

the river giving rise to planar failure along the valley dipping joints. Hard, compact 

and high strength limestone constitutes the rockmass around the scar. Once the 

reservoir is filled up, there will be no toe cutting action of the river therefore 

eliminating the possibility of any rock mass failure in future. 

13.5.2.5 Landslide - 31 

It is an active landslide located on the left hill slope at about 600m upstream of the 

dam axis (Figure 13.2), with its toe at EL 390 m and Crown at EL 540 m. The rock 

mass exposed in the slide area is fine to medium grained feldspathic gneiss. The 

maximum length of the landslide is 160 m, whereas its width varies from 20 m to 70 

m. A 70-80 m wide zone extending from the toe to the crown portion is 


13-10


characterized by the presence of closely spaced parallel to sub-parallel shears. 

The thickness of individual shear zone varies from a couple of meters to 20m with 

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moderate dip (50-60°) towards NE. Within the shear zone the rock mass is highly 

sheared/crushed and shattered. At places due to intense shearing 1-2 m thick talc 

bands/clay seams have developed rendering the rock mass more susceptible to 

failure. As the shears are foliation parallel, the shear zone shows swerving nature 

due to the superimposition of latter phases of deformation. The strike of the shear 

zone makes an acute angle (30° to 35°) with the river course. 

Detailed geological mapping of the landslide revealed that the rock mass failure 

has resulted due to the cumulative effect of the three sets of discontinuities, viz., 

030 ° -065 ° / 45 ° -65° (S1); 210 ° -235 ° / 40 ° -65 ° (S2); 163 ° -185 ° /20 ° -45 ° (S3) and the 

foliation parallel shears characterized by the presence of talc. Foliation parallel 

shears are dipping upstream, however, the wedges formed by the intersection of 

three sets of joints are getting disloged due to the presence of talc along the 

shears. The conditions become more unfavourable during rain, as talc gets 

lubricated and facilitates failure of rock mass. 

Figure 13.2: Active landslide about 600m u/s of the dam axis. Note the debris cone at the 

base of the landslide 


13-11


S. 

No. 

CISMHE 

Remedial Measures: 

The toe of the landslide is located at EL 390m and the crown extends up to EL 

540m. The debris cone occurring at the base of the landslide may be kept as it is, 

and toe wall / plum concreting is to be provided at the toe (EL 390 m) of the 

landslide and afterwards from up to EL 450 m, the entire slide zone has to be 

treated with proper thickness of shotcrete. 

Even after providing toe wall and shotcrete of adequate thickness, the rock mass 

behind will get charged with water, which will increase the pore pressure and 

lubricate talc occurring along the foliation parallel shears. During the operation of 

powerhouse and more particularly during the flushing of reservoir adequate 

measures like drainage/ weep holes will be provided so that the rock mass behind 

remains stable. 

The summarized description of the critical slides is tabulated below. Three 

geological cross sections were prepared (refer Plates 13.5 a, b & c) along the 

longer section of the slide, and the proposed protection measures have been 

shown to stabilize the zone during draw down. 

Slide 

ID No. 

1 1 

2 3 

3 5 

4 8 

5 25 

6 31 

Coordinates Landslide Type Vegetation Type Seepage Lithology 

E835707.02 

N3095985.08 

E 835472.08 

N 3096477.56 

E 836527.76 

N 3095618.63 

E 835789.75 

N 3097968.70 

E 835852.32 

N 3097845.53 

E 833273.97 

N 3088730.52 

Slide scar on 

Left bank 

Debris slide 

Shallow debris 

slide/scree, gently 

sloping 

Slide scar on 

Left bank 

Slide scar on 

Left bank 

Wedge failure 

accelerated by 

the presence of 

foliation parallel 

shears containing 

talc. 

No 

vegetation 

Sparse 

vegetation 

No 

vegetation 

No 

vegetation 

Dormant 

Dormant 

No 

seepage 

No 

seepage 

Active seepage 

Graphite 

schist 

Debris 

Shallow debris 

& scree 

Dormant No Limestone 

Vegetation Dormant Seepage Limestone 

No 

vegetation 


Active 

No 

seepage 

Feldspathic 

gneiss 

13-12


13.6 COST ESTIMATE 

A total of 28 landslides of different magnitude and activity were interpreted from 

cartosat1 stereo images using state-of-the art image processing techniques. 

However, not all landslides are significant from the point of view of reservoir 

stability of Demwe Lower H. E. Project. Landslides with ID nos. 1, 3, 5, 8, 25, and 

31 are located in the critical zone between EL. 365m and EL 424.80m (FRL). 

These slides will be vulnerable to the fluctuation in the water level within the live 

storage as well as during the flushing out operation twice in a year. Keeping it in 

view, detailed field studies of all these slides were under taken on ground by taking 

arduous traverses. 

CISMHE 

It revealed that three slides scars (ID nos. 1, 8 & 25) have resulted due to the 

undercut action of the river giving rise to planar failure along the valley dipping 

joints. These landslides are located in the upper reaches of the proposed reservoir. 

Once the reservoir is filled up, there will be no toe cutting action of the river due to 

the vertical columns of water (EL 389m to EL 424.8m), thus eliminating the 

possibility of any rock mass failure in future. Out of the six landslides, three slides 

(ID nos. 3, 5 & 31) require treatment to make the reservoir rim stable, which is 

described in brief below. 

Landslide (ID no.3) in its major part is sparsely vegetated and stabilized at present, 

and the debris comprises admixture of big rock blocks and smaller rock fragments 

of quartzite. In between FRL (EL 424.8m) and maximum drawdown level (EL 

408m) the debris accumulation due to its open framework will not be subjected to 

pore pressure fluctuations, therefore will remain more or less stable. No specific 

remedial measure is required for this already stabilized landslide. 

Landslide (ID no. 5) has resulted due to the failure of the unconsolidated slope 

wash material. To contain further sliding, toe wall in the terminal part followed by 

shotcreting up to FRL (EL 424.8m) may be carried out. To stabilize the debris 

accumulation above the FRL, a toe wall with drainage holes may be constructed 


13-13


above the FRL. Adequate measures such as drainage/ weep holes are to be 

provided so that the water charged mass behind remains stable. 


CISMHE 

Landslide (Id no. 31) is an active landslide located on the left hill slope at about 

600m upstream of the dam axis. The rock mass exposed in the slide area is fine to 

medium grained feldspathic gneiss. The debris cone occurring at the base of the 

landslide may be kept as it is, and toe wall / plum concreting is to be provided at 

the toe (EL 390 m) of the landslide and beyond that shotcrete of adequate 

thickness will be provided up to the FRL (EL 424.8m) of the reservoir. The rock 

mass behind will get charged with water, which will increase the pore pressure and 

lubricate talc occurring along the foliation parallel shears. During the operation of 

powerhouse and more particularly during the flushing of reservoir to maintain pore 

water pressure in the rock mass behind shotcrete, drainage/beep holes will be 

provided so that the rock mass behind remains stable. Two landslides need to be 

treated to make the reservoir rim completely stable to withstand the water level 

fluctuations resulting during generation of power and flushing out operation of the 

reservoir. The estimated cost for the aforesaid treatment is tabulated below. 

S. No. Slide ID No. 

Cost of toe wall 

(in Rupees) 

Cost of Shotcrete 

(in Rupees) 

1 5 2,42,72,050 59,01,705 

2 31 1,23,83,820 4,15,15,245 

Total cost 

(in Rupees) 

8,40,72,820 

13-14

Plate 13.1

Plate 13.2

Plate 13.3

Plate 13.4a

Plate 13.4b

Plate 13.4c

Plate 13.5a

Plate 13.5b

Plate 13.5c



CISMHE 

CONSTRUCTION METHODOLOGY AND EQUIPMENT 

14 

PLANNING 

Appropriate construction methodology and equipment planning can mitigate the 

adverse impact to surrounding environment (if any) during construction phase. 

The damages can be more if the project is delayed due to inadvertent planning. 

Moreover, a good planning must take into account the methods and equipment 

through which the project can be completed with minimal irreversible loss to the 

environment. 

Demwe Lower HE Project is located in the foothills of Mishmi ranges, which 

receive rainfall during the monsoon months starting from May till September. The 

details of construction methodology and equipment planning for the Demwe 

Lower HE project are available in the DPR Demwe Lower HEP. This plan has 

been prepared considering the accessibility of the region, weather condition 

throughout the year and raw material availability. All the major works of the 

project proposed to be executed through world class experienced contractors who 

shall be selected on the basis of International Competitive bidding process. Latest 

equipments are proposed to be used in avarious activities during construction. 

The following sections in this chapter provide excerpts from the DPR Demwe 

Lower HEP related to the construction planning proposed to achieve the goal of 

commissioning the project within 61 months. 

14.2 TRANSPORTATION OF MEN, MATERIAL AND EQUIPMENT 

The Demwe Lower Dam site is located at 692 km from Guwahati (along NH-37), 

215 km from Dibrugarh, 160 km from Tinsukia, 80 km from Roing and 80 km 

from Demwe Upper Dam site. The nearest Airport is at Dibrugarh.The project is 

Environmental Management Plan – Construction Methodology and Equipment Planning 

14-1


at about 40 km from the district headquarters at Tezu, where a helipad is 

maintained by State Govt. and where weekly helicopter services are available 

connecting Dibrugarh and Itanagar. Since the Demwe Lower project site is 

located on the National Highway 52 and is well connected with Tinsukia in 

Assam, which is the commercial hub of Assam state and is the nearest Broad 

Gauge railhead, the Construction equipment can be transported either by Rail 

upto Tinsukia which is about 160 km from the project site or via road (NH 37) 

from Guwahati. The mobilization of men and equipment can take place even 

during the monsoon months. However the best option would be to make use of 

the Tinsukia Railhead from where the men, material and equipment can be 

transported economically by road. 

14.3 CONSTRUCTION POWER 

Construction power for main works i.e. for Dam, Tunnels, Power House, 

Batching and Mixing plants, Workshop, quarry etc. would be arranged by the 

Contractor, while the power required for colony and offices would be arranged by 

the ADPPL. It is estimated that an overall peak requirement of about 17 MW 

(Table 14.1) will be required for the project. 

Table 14.1: Requirement of construction power 

Area Maximum Load Demand (MW) 

Work site for Dam/Diversion Tunnel/Pressure Shaft 12 

Work site for Power House / Crushers /Sand mills 2 

Central Mechanical Workshop 1 

Workshop for Penstock Works 1 

Colony Area 1 

Total 17 

The NOx, HC, CO emissions from the DG sets should be below the prescribed 

limits of CPCB. The Noise from DG set is required to be controlled by providing 

CISMHE 

an acoustic enclosure or by treating the room acoustically. The acoustic 

enclosure or acoustic treatment of the room shall be designed for minimum 25 dB 


14-2


(A) insertion loss or for meeting the ambient noise standards, whichever is on the 

higher side. If the actual ambient noise is on the higher side, it may not be 

possible to check the performance of the acoustic enclosure/acoustic treatment. 

Under such circumstances the performance may be checked for noise reduction 

upto actual ambient noise level, preferably, in the night time. The measurement 

for insertion loss may be done at different points at 0.5 m from the acoustic 

enclosure/room, and then averaged. The DG set shall be provided with proper 

exhaust muffler with insertion loss of minimum 25 dB(A). These limits shall be 

regulated by the State Pollution Control Board and the State Pollution Control 

Committees. The manufacturer shall offer to the user a standard acoustic 

enclosure of 25 dB(A) insertion loss and also a suitable exhaust muffler with 

insertion loss of 25 dB(A). The project authority shall make efforts to bring down 

CISMHE 

the noise levels due to the DG set, outside its premises, within the ambient noise 

requirements by proper siting and control measures. Installation of a DG set must 

be strictly in compliance with the recommendations of the DG set manufacturer. 

A proper routine and preventive maintenance procedure for the DG set should be 

set and followed in consultation with the DG set manufacturer which would help 

prevent noise levels of the DG set from deteriorating with use. 

In accordance with the EPA Notification (GSR 742(E) dt. 30 th Aug, 1970 and SO 

8(E) dt Dec 31, 1990) the following pollution control measures are necessary for 

the Crusher and Batching plant areas: 

1. Dust containment cum supression system for the equipment. 

2. Construction of wind breaking walls. 

3. Construction of the metalled roads within the premises. 

4. Regular cleaning and wetting of the ground within the premises. 

5. Growing of a green belt along the periphery: Since there are good forest in 

the periphery the creation of a green belt may not be required. However, 

to improve the forest cover some plants can be planted. 


14-3


The suspended particulate matter level between 3 to 10 metres from any 

process equipment of a stone crushing unit shall not exceed 600 µg/m. 

14.4 TELECOMMUNICATION 

During construction of Demwe Lower HE Project, it is proposed to have a multi 

channel VSAT connection at site. LDST connection from MTNL exchange, Delhi 

and local radio/wireless communication are also required to be established 

during the construction of the project. For better communication network, OFC 

CISMHE 

connection between BSNL telephone exchange at Tezu and project site is also 

planned. LAN connectivity for inter office communication is planned for better 

efficiency in office. 

14.5 CONSTRUCTION METHODOLOGY 

14.5.1 Infrastructure Works 

The Demwe Lower HE Project site is located on the National Highway with most 

of the bridges having 70R specifications. Some of the bridges, which are of lower 

specifications, are being upgraded by Border Road Organisation (BRO) to 70R 

loading. There is a requirement of a new 40R bailey bridge upstream of the dam 

axis for crossing the river and accessing the left bank of Lohit River, where the 

rock quarry is located. This bridge is expected to be completed within 18 months 

time. The existing 18R bridge across Tidding River lying upstream of the Dam 

site, close to the confluence of Lohit and Tidding will also need to be replaced, as 

the existing bridge would come within the submergence area. Approach to the 

new bridge will also be constructed. There is a requirement of constructing 23 km 

of access roads on the left and right bank for reaching various sites and work 

locations. 

All the access roads and bridges are expected to be completed within 18 months 

of the Project construction commencement date, which is 1 st April-2010. The 

construction of temporary and permanent buildings, offices, Guest houses and 

other recreational facilities are proposed to be completed within 18 months i.e. by 

Sept. 2011. 


14-4


14.5.2 Major Hydraulic Structures 

The Construction methodology for major hydraulic structures is discussed below. 

The equipments to be used during construction of different appurtenant structures 

are listed in Table 14.2. 

Table 14.2: Number of equipments to be used for the purpose of construction of different 

Equipment 

appurtenant structures of Demwe Lower HE project 

Diversion 

Tunnels 

Pre Coffer 

Dams 

Stage 

Coffer 

Dam 

Concrete 

Gravity 

Dam 

CISMHE 

Pressure 

Shaft 

Power 

House 

and Tail 

Race 

Channel 

25t Dumpers 24 - - - 20 - 

Air Compressors (500 cfm) 4 - - - 3 - 

Batching and Mixing Plant 

(100/300 cum/hour) 

Coarse Aggregate Processing 

Plants 750 TPH 

Concrete Batching and Mixing 

Plant (100 cum/hr) 

- - - - - 1 

- - - 2 - - 

1 - 1 - 1 - 

Concrete Pump 40 cum/hr 4 - 2 - 5 - 

Concrete Pumps (40 cum/hr) - - - - - 3 

Concrete shutters for overt 

concreting 

4 - - - - - 

Crawler Dozer (50 D) 1 - - - 1 - 

Crawler Dozer (80 D) 1 - - - 1 - 

Crawler Drilling Machine - - 2 - - - 

Dewatering Pumps (20 HP, 10 

HP and 5 HP) 

2 each - - - 3 each - 

DG Set (500 KVA) 2 - - 6 4 6 

Dozer-D50 - 2 2 2 - 2 

Dozer-D80 - 2 - 2 - 1 

Dumpers 25 T - 20 30 40 - 20 


14-5


Equipment 

Diversion 

Tunnels 

Pre Coffer 

Dams 

Stage 

Coffer 

Dam 

Concrete 

Gravity 

Dam 

CISMHE 

Pressure 

Shaft 

Power 

House 

and Tail 

Race 

Channel 

Electrically Operated Winches - - - - 5 - 

Excavators (3 cum) - 10 10 - - - 

Fine Aggregate Processing 

Plants 50 TPH 

- - - 12 - - 

Front End Loader - - - - 4 - 

Hydra Mobile Crane 2 - - - 2 - 

Hydraulic Excavator 0f 3/6 cum 

capacity 

- - - - - 6 

Hydraulic excavators (2 cum) 4 - - - - - 

Hydraulic excavators (3 cum) - - - - 5 - 

Hydraulic Excavators 6/3 cum 

capacity 

- - - 10 - - 

Jack Hammers 10 3 3 - 10 - 

Jet Grouting Equipment - - 2 sets - - - 

Loader Cum Excavator 4 - - - 2 - 

Mobile telebelt conveyor (275 

cum/hr capacity) 

- - - - - 1 

Raise Climbers - - - - 5 - 

Shortecrete machine with 

Robo Arm 

2 - - - 2 - 

Single Boom Rockbolter 2 - - - 2 - 

Three boom Drill Jumbos 2 - - - 2 - 

Tippers 10 - - - - - 

Transit Mixers 6 Cum Capacity - - 5 - - 10 

Ventilation Fan and ducts 4 - - - 5 - 

Vibratory Rollers 10/20 T - 3 4 - - - 

Wagon Drills 2 - - - 2 - 

Wagon Drills - 1 1 6 - 4 


14-6


14.5.2.1 Diversion Tunnels 

In order to cater to 1 in 25 year non-monsoon discharges in Lohit River, 5 Nos. of 

diversion tunnels, each of 14 m diameter and about 1100 m of average length has 

been planned. In addition to this a 6 m dia, 950 m long diversion tunnel has been 

planned on the left bank to ensure continuous supply of water to Prasuramkund, 

which is a holy place. 

The 14.0 m dia tunnels have been planned to be excavated by Heading and 

Benching method, while the 6 m dia tunnel would be done full face. For the 

purpose of Heading excavation for 4 tunnels and 8 faces (14 m diameter), it is 

proposed to deploy 2 three boom drill jumbos from each side. The operations in 

the tunnels would be staggered in such a way that 2 drill jumbos at each side 

(Outlet and Inlet) can cater to all the tunnels. The 6 m diameter tunnel shall be 

excavated full face and would be completed well within the completion time of the 

larger diameter and longer diversion tunnels. 

The Concrete lining for the diversion tunnels are proposed to be done in two 

stages. The overt lining will be done by using specially fabricated shutters and 

invert lining by using templates. For the Overt concrete lining 12 m long telescopic 

shutters would be fabricated for each tunnel and for each face. Thus a total of 8 

numbers 12 m long telescopic shutters with hydraulic support and release system 

would be fabricated and erected inside each face. Total time required for the overt 

lining from the Outlet face would be about 5 months. Similarly the Overt lining 

from each of the intake faces would take 3 months time. The Invert lining and 

grouting would follow the overt lining and these activities would be completed 

within 2-3 months of completion of the overt lining. 

14.5.2.2 Coffer Dams 

Pre-Coffer Dam 

The Upstream cofferdam has been provided in order to divert requisite discharge 

through the diversion tunnels. For constructing the upstream cofferdam, a precoffer 

dam of dumped material is to be constructed in the lean season. The 


CISMHE 

14-7


upstream located pre-coffer dam has been planned as a 14 m high dumped 

rockfill structure. This pre-coffer dam is to be constructed by using the diversion 

tunnel muck and excavated material available from the Dam abutment stripping. 

Upstream Coffer Dam 

The upstream cofferdam is proposed to be constructed from rockfill material, 

which would be locally obtained from the Excavation of the Dam, and some 

material from the tunnels. The upstream cofferdam is proposed to be 

constructed in two stages. 

Downstream Cofferdam 

The downstream coffer dam is also a dumped rockfill structure which has been 

provided downstream of the 6 m diameter diversion tunnel to avoid any back 

flow in the dam excavation area. Since this diversion tunnel is expected to 

discharge a maximum of only 400 cumecs, the downstream coffer dam would be 

a 8 m high structure only and would be constructed in a month time at the time 

when the river has been diverted through the 14 m dia tunnels and the gates of 6 

m dia tunnel would be closed during that period. 

14.5.2.3 Concrete Gravity dam 

Concrete Gravity dam, which is proposed to be 163.12 m high, is the most 

important structure of the project. The construction of this structure involves i) 

excavation of (37.50 lakh cum), ii) concreting in O.F and N.O.F blocks – (43.6 

lakh cum) 

CISMHE 

Entire work of dam construction including excavation of abutments starting from 

the date of river diversion on December 2011 is to be completed in 54 months 

time that is during May 2016. However, the stripping of the abutments will 

commence before the river diversion. 


14-8


Transport and Placing of Concrete in different work areas during dam 

construction 

To reach all corners of the dam and to safely top it out, it is proposed to use two 

conveyor systems that will end with total of three (3) placing devices plus three 

mobile units fed by trucks that will place concrete from outside of the dam in all 

lifts within its reach. Two conveyor lines will include 2 x 360 m long feeder 

conveyors that will feed set of total of 14 x 40 m long climber conveyors plus 3 x 

30 m long link conveyors to feed total of 3 x conveyor placing device. Climber 

conveyors will zigzag down and up the dam as per daily schedule requirements. 

CISMHE 

Mobile equipment will include 2 x 39 m long telescopic conveyors mounted on 

truck chassis and 1 x 62 m long telescopic conveyor mounted on hydraulic crane 

chassis. These units will move around and on the dam blocks to pour concrete in 

all blocks within its realistic reach. Total of 8 numbers of Concrete Haulers of 6 

m 3 will haul concrete from mixing plants and feed mobile equipment as per daily 

needs over total of three (3) mobile metering hoppers 6 m 3 in size (to optimize 

number of transit mixers hauling concrete and feed conveyors as per actual need 

in the lift). 

With the methodology mentioned above, there will be a total of five (5) different 

and independent means of placing concrete in the dam at all times during the 

works. The fifth is the third placing device and part of conveyor system that will 

be fed by Concrete haulers as per the needs of daily work programs. 

Due to placing capacity requirement of maximum 275 m 3 /h per conveyor line, 

24” (610 mm) wide belt is selected that can do up to 275 m 3 /h. This size of 

conveyor is lighter and much easier to set for pour and frequent reposition 

throughout the works. Feeder overland conveyors will be on fixed supports made 

at site and conveyors zigzagging up and down the dam will be supported at ends 

by removable and reusable supports also made at site. 


14-9


Total numbers of climber conveyor enable reaching the bottom of the dam as 

well as topping it out going down at maximum 25 degrees and climbing up at 

+20 degrees. All conveyors will be required to reach far top corners of the dam. 

That will by itself alone provide for great reserve and flexibility. Two mixing 

plants will be directly feeding concrete on to two conveyor lines. 

CISMHE 

Vibration 

To vibrate all concrete in lifts on the dam it is proposed to use total of 5 x 8 x 150 

mm vibrator gangs attached to the excavator on crawlers (approx. 16-22T) plus 

3 x 4x150 mm vibrator gangs attached to excavator on crawlers (approx. 7-10T). 

Service Cranes 

All service works such as moving equipment for raising forms, vibration, steel 

reinforcement and all other services needed at site like this including 

repositioning of conveyors and placing devices, will be done with tower cranes of 

20T capacity at 65 m with the maximum reach being not less than 85 m. 

14.5.2.4 Pressure Shaft 

Five numbers of 10 m diameter pressure shafts of 571 m average length has 

been provided to feed the five Vertical Francis turbines. 

The work of Pressure shaft includes open excavation at the Intake and 

powerhouse end, portal construction at both the faces for each tunnel and 

construction of inclined drop shafts. Tunneling shall be carried out by drilling and 

blasting method using heading and benching approach. The tunnel from the 

outlet portal can be started after excavation necessary for portal opening from 

that face (which will also cover the part excavation for powerhouse pit). The 

excavation would be done in Heading and Benching by using 3 boom drill 

jumbos. A cycle time of about 14 hours for the Heading excavation for each 

pressure shaft has been assumed. This would mean a monthly progress of 

about 125 m from each of the face, considering 25 working days in a month and 

each pull of 3.0 m. The drop shaft excavation has been planned to be carried out 


14-10


simultaneously from the top and the bottom. While the excavation from the top 

would be done by the conventional drilling-blasting method, the excavation from 

the bottom shall be done by using Raise climber and by making a smaller 

diameter pilot shaft of about 3 m diameter for this purpose. After the bottom pilot 

shaft meets the already completed shaft from the top, the excavation shall be 

continued from the top by slashing and mucking would be done from the bottom. 

The erection of steel liners can be done after the completion of excavation of the 

entire pressure shaft. 

14.5.2.5 Power house and Tailrace channel 

The surface powerhouse of Demwe Lower HE Project is located on the right 

bank of the Lohit River housing 5 vertical Francis turbines of 342 MW each and 

one unit of 40 MW. Part of the powerhouse pit excavation would be completed 

along with the excavation for portal opening of the 5 pressure shafts. The 

excavation of a part of the tail race channel lying between the maximum flood 

level of the river and the tailrace channel’s powerhouse end would be left as a 

natural flood protection for the powerhouse pit. 

14.6 CONSTRUCTION MATERIAL 

14.6.1 Required Construction Material 

Based on the DPR stage designs and drawings various construction materials 

and their estimated requirements for the construction of the project are i)Coarse 

aggregate for concreting (54.5 lakh cum), ii) Sand for concreting (27.30 lakh 

cum), iii) Cement (16.4 lakh MT), and iv) Steel Reinforcement (1,05,866 MT). 

These quantities of major construction materials are exclusive of hydromechanical 

works, steel liners and E&M equipment, switchyard steel structures 

etc. In addition to this many other minor items like steel fibre reinforcement, wire 

mesh, admixtures for concreting / grouting, bentonite, silica fume, bricks and 

other items related to building architecture, water supply and sewage works 

including fittings and fixtures would be required. 


CISMHE 

14-11


14.6.2 Availability of Construction Material 

The surveys for the construction material have been carried out and quarries 

have been identified. The principal construction material like aggregate, rock etc. 

are available in sufficient quantity in and around project areas from the identified 

locations. 

CISMHE 

River bed deposits along the river Lohit and two shoals constituting the terrace 

(T0) on the right bank, continuing for about 2 km length in the downstream of the 

Dam Axis contain more than 14 lac m 3 of natural aggregate (coarse and fine) 

including boulder and cobbles. Excavated material from the Power House and Tail 

Race Channel excavations is the additional source of construction material, which 

will contribute about 8.0 Lac m 3 of usable material as coarse and fine aggregate. 

A rock quarry located about 2 km upstream of the Dam Axis on the right bank of 

the Lohit river is the other potential source of construction material. From this rock 

quarry at least 81.8 lakh m 3 of usable material will be extracted for the production 

of coarse and fine aggregates. 

The RBM deposited along the course of the Lohit River is well sorted and 

homogeneous in nature. The RBM exposed in the river bed and adjacent shoals 

can be classified mainly into three categories, viz., boulders with minor amount 

of cobbles, pebbles and sand; admixture of boulders, cobbles, pebbles and 

sand; predominantly sand with minor amount of cobbles, pebbles and gravels. 

The boulders predominantly comprise granite, granite gneiss, porphyritic granite, 

leucocratic granite, ultramafics and pegmatite in order of decreasing abundance. 

Various constituents of the RBM appear to have been transported from the 

upper reaches of the Lohit catchment, mainly from the granodioritic complex 

exposed upstream of the confluence of the Lohit and Tidding rivers. The RBM 

lying along the Lohit river course appears suitable for construction of the 

Concrete Gravity Dam and its appurtenant structures. 

In addition, huge amount of construction material are available in six terraces (T0 

to T5) on the right bank of Lohit river. The boulders comprise granite, granite 


14-12



CISMHE 

gneiss, porphyritic granite, leucocratic granite, ultramafics and pegmatite in order 

of decreasing abundance. 

As the Surface Powerhouse is proposed in the area occupied with the terrace 

material on the right bank, suitable excavated material may be utilized for civil 

construction works during excavation. In addition, the excavation down to 30m 

depth for founding dam and spillway structure will contribute significantly as 

aggregate material. 

The requirement of cement for the project will be procured from the reputed 

manufacturers/stockyards in the adjoining states of West Bengal, Bihar, Orissa, 

Madhya Pradesh etc. This will involve carriage by Railway upto Tinsukia, Assam 

and by Roadways upto the Project Site. 

The required quantity of steel for reinforcement, structural steel, rock bolting etc. 

shall be procured from Steel Authority of India Ltd. (SAIL) and other Agencies 

like TISCO etc. This will involve carriage by Railway upto Tinsukia (Assam) and 

by Roadways upto the Project Site. 

14-13



CISMHE 

ENVIRONMENTAL MONITORING PROGRAMME 

Environmental Monitoring is an essential tool in relation to environmental 

management as it provides the basis for rational management decisions 

regarding impact control. Monitoring shall be performed during all stages of the 

project (namely: construction, commissioning, and operation) to ensure that the 

impacts are no greater than predicted, and to verify the impact predictions. The 

monitoring program will indicate where changes to procedures or operations are 

required, in order to reduce impacts on the environment or local population. The 

monitoring program for the Demwe Lower Hydropower Project will be undertaken 

to meet the following objectives: 

• To monitor the environmental conditions of the Lohit River and the reservoir 

as impacted by the Demwe Lower Hydropower Project; 

• To check on whether mitigation and benefit enhancement measures have 

actually been adopted, and are proving effective in practice; 

• To provide information on the actual nature and extent of key impacts and the 

effectiveness of mitigation and benefit enhancement measures which, 

through a feedback mechanism, can improve the planning and execution of 

future, similar projects. 

15.2 AREAS OF CONCERN 

From the monitoring point of view, the important parameters are water quality, air 

quality, noise, erosion and siltation, landuse, afforestation, etc. An attempt is 

made to establish early warning of indicators of stress on the environment. 

Suggested monitoring details are outlined in the following sections. 

Environmental Management Plan – Environmental Monitoring Programme 15-1 

15


15.2.1 Water Quality 

Construction Phase 

It is proposed to monitor the effluent before and after treatment from sewage 

treatment plant. The frequency of monitoring could be once per month. The 

sampling sites shall be Colony area, Power house site, Dam site; 3 km down 

stream of dam site, Confluence point of Tidding river. A total of 60 samples need 

to be analyzed every year. The parameters to be monitored include pH, Biochemical 

Oxygen Demand (BOD), Total Suspended Solids (TSS) and Total 

Dissolved Solids (TDS). The cost of treatment of one sample is expected to be 

about Rs, 2000/-. Thus, total cost for analysis over a period of 5 years including 

10% escalation every year works out to Rs.6.60 Lakhs. The monitoring is 

proposed to be done over a period of 5 years. 

CISMHE 

Operation phase 

The surface water quality of the proposed reservoir and river Lohit can be 

monitored thrice a year (summer, pre and post-monsoon seasons). The 

proposed parameters to be monitored include; pH, temperature, electrical 

conductivity, turbidity, total dissolved solids, calcium, magnesium, total hardness, 

chlorides, Sulphates, Nitrates, DO, COD, BOD, Iron, Zinc and Manganese. 

The sampling sites shall be: Confluence Point of Tidding river and Lang river with 

Lohit river, Reservoir water, Parasuram- Kund, and downstream of the 

confluence of the tail race discharge. 

The total cost of analysis will be Rs.1.50 Lakhs per year (3 times x 5 sites 

@10000 per sample) . During project operation phase, a Sewage Treatment 

Plant (STP) is proposed to be set up to treat the effluent from the project colony. 

Once every month, it is envisaged to analyze a sample each before and after 

treatment from the STP. The parameters to be analyzed include pH, Biochemical 

Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended 

Solids (TSS) and Total Dissolved Solids (TDS). The cost of analysis of 24 

Environmental Management Plan – Environmental Monitoring Programme 15-2


CISMHE 

samples @ Rs.2500/sample works out to Rs 0.6 Lakhs/year. Thus, total cost for 

analysis in project operation works out to (1.50+.60) Rs.2.10 Lakhs/year. 

15.2.2 Air Quality 


The ambient air quality monitoring during construction phase will be carried out 

by the self established an environmental lab or as per requirement by the 

external agency, approved by State Pollution Control Board. Every year 

monitoring is to be done for the following three seasons: 

• Winter 

• Summer 

• Post-monsoon 

The frequency of monitoring could be twice a week for four consecutive weeks at 

each station for each season. The parameters to be monitored are Respirable 

Particulate Matter (RPM) and Suspended Particulate Matter (SPM), Sulphurdioxide 

(SO2) and Nitrogen Oxides (NOx). 

Every year, ambient air quality is to be monitored for (4 stations x 2 days/week x 

4 weeks x 3 seasons) 96 days. A total cost of Rs. 2.9 Lakhs/year @ Rs. 

3000/day can be earmarked for this purpose. For a construction phase of 5 years 

the total cost works out to Rs. 17.7 Lakhs considering 10% escalation every year. 

15.2.3 Noise 


Noise emissions from vehicular movement, operation of various construction 

equipment may be monitored during construction phase at major construction 

sites. The frequency of monitoring could be once every three months. For 

monitoring of noise generators an Integrating Sound Level Meter will be required 

for which an amount of Rs. 5.0 Lakh can be earmarked. 



15.2.4 Meteorological Aspects and Environmental Lab 

It is recommended that a meteorological laboratory be set up with the 

environmental laboratory at site to monitor various meteorological parameters, 

Instruments for continuous monitoring of following parameters need to be 

commissioned: 

• Temperature 

• Rainfall 

• Humidity 

• Cloud cover 

• Wind speed 

• Wind direction 

CISMHE 

An amount of Rs. 101.5 Lakh can be earmarked for commissioning of laboratory 

for monitoring various meteorological and environmental aspects. The break up 

of cost for Environmental Division is shown in table 15.1. 

15.2.5 Erosion and Siltation 

Project Construction Phase 

Silt analysis is proposed to be carried out for project construction phase. The 

frequency of monitoring could be done once per month from two different sites. 

The various parameters to be monitored include soil erosion rates, stability of 

bank embankment, etc. The cost of analysis of 24 samples @ Rs.1500/sample 

works out to Rs 0.18 Lakhs/year. The total cost for Silt analysis shall be 1.98 lakh 

with escalation charge @ 10% for 5 years. 

Project Operation Phase 

Soil erosion rates, slope stability of embankments of dam, efficacy of soil 

conservation measures, need to be closely monitored ones a month. The Demwe 

Lower Hydropower Project staff at the site can do the study. The study should be 

undertaken throughout the life of the project so as to design the soil erosion 

prevention measures and also for the rehabilitation of the project. The various 

parameters to be monitored include soil erosion rates, stability of bank 



embankment, etc. The total cost of monitoring will be .36 lakhs/year @ 

Rs.1500/sample (12x2). 

15.2.6 Ecology 


During construction phase monitoring of various management measures 

proposed under the environment management plan like CAT, Forest protection 

plan, Wildlife Management Plan and to monitor and prevent the illegal pouching 

of Wildlife, Collect and record information on new ecological habitants if any etc. 

CISMHE 


Status of afforestation programmes, changes in migration patterns of the aquatic 

and terrestrial fauna species should be studied. The study could be undertaken 

with a frequency of 5 years till the entire design life of the dam. A provision of 

Rs.5.0 lakh per study can be kept for this purpose. Thus, the annual expenditure 

can be taken as Rs.1.0 lakh/year. Forest Department can conduct the study. 

15.2.7 Fisheries 


A monitoring programme has been suggested during the project construction 

phase to avoid illegal fishing activity and monitor the minimum flow requirements 

and to monitor the aquatic ecology. The cost of analysis of 12 samples @ 

Rs.1500/sample works out to Rs 0.18 Lakhs/year. The total cost for aquatic 

monitoring shall be 0.99 lakh with escalation charge @ 10% for 5 years. 


Monitoring of fisheries in the reservoir will be essential to achieve sustainable 

yield of fish. Some of the parameters to be monitored are phytoplanktons, 

zooplanktons, benthic life and fish composition, etc. Based on human resources 

and facilities available, monthly observations in time and space need to be made. 

The parameters can be monitored twice at the water sampling sites given above. 

The monitoring can be conducted by Fisheries Department or the 



environmentalist who will be on the site. The total cost for monitoring will be 1.80 

lakh/year (2times in month, 5 different sites @1500/-) 

15.2.8 Incidence of Water-Related Diseases 

During project construction phase, the incidence of various water-related 

diseases can be monitored. The various parameters to be covered include 

various diseases cause and control measures. The monitoring can be conducted 

once in a year by the medical staff posted at the dispensary near construction 

site. The monitoring can be done in project colony and settlements within 2-3 km 

of the project site. 

15.2.9 Minimum Releases 

It is proposed to continuously monitor release of minimum discharge from the 

dam through an electronically operated system. An amount of Rs. 15 Lakhs is 

proposed to be earmarked for this purpose. 

15.3 TOTAL BUDGET FOR ENVIRONMENTAL MONITORING PROGRAMME 

Total cost estimated for environmental monitoring programme and laboratory 

establishment is 148.77 Lakhs during construction phase and 5.26 lakhs during 

operational phase. 

Table 15.1: Cost of Environment Division 

S.No. Items Cost (Rs.) 

1 Capital cost 

Office building including laboratory 150sqm @ 9,00,000 

Office furnishing including computer etc 15,00,000 

Laboratory equipment 50,00,000 

Vehicle 1 no. 6,00,000 

2 Recurring cost for 5 years 

Manpower (1 engineer, 1 T.A.,2 Assistants) @ 30,60,000 

Vehicle running cost @ Rs 1,30,000/year 6,50,000 

Office maintenance and consumables @ Rs 10,00,000 

3 Services of Environmental Advisor @ Rs. 5,00,000 

Grand Total 101,50,000 


CISMHE


Table 15.2: Cost estimates for Environmental Monitoring Programme 

Cost estimate During Construction Phase 

Particulars Cost (Lakhs) 

Water quality 6.6 

Air quality 17.7 

Noise 5.0 

Meteorological Laboratory & Environmental Division 101.5 

Minimum release of water 15.0 

Erosion and Siltation 1.98 

Fisheries 0.99 

Total 148.77 

Cost estimate during Operation Phase 

Particulars Cost (Lakhs)/year 

Water quality 2.10 

Erosion and Siltation 0.36 

Ecology 1.0/year for five year 

Fisheries 1.80 

Total 5.26 

15.4 SUMMARY OF ENVIRONMENTAL MONITORING PROGRAMME 

The summary of environmental monitoring programmes during construction 

phase and operational phase are given in Tables 15.3 and 15.4 respectively. 

Table 15.3: Summary of Environmental Monitoring Programme during construction 

Phase 

S. Items to be 

Parameters Frequency Location 

No. monitored 

1. Effluent from STPs pH, BOD, COD, TSS, 

TDS 

2. Water-related 

diseases 

Identification of 

water related 

CISMHE 

Once every month Before and after 

treatment from the 

SPTs at various 

labour camps 

Three times a 

year 

Labour camps 

and colonies 



S. 

No. 

Items to be 

monitored 


diseases, adequacy 

of local control and 

curative measure, 

etc. 

3. Air quality SPM, RPM, SO2 and 

Nox 

4. 

Noise Equivalent noise 

level (Leq) 

Once every 

season 

Once in three 

months 


CISMHE 

At major 

construction sites 

At major 

construction sites. 

Table 15.4: Summary of Environmental Monitoring Programme during Project Operation 

Phase 

S. 

No. 

Items to be 

monitored 


1. Water pH, Temperature, EC, 

Turbidity, Total Dissolved 

Solids, Calcium, 

Magnesium, Chlorides, 

Sulphates, Nitrates, DO. 

COD, BOD, Iron, Zinc, 

Manganese. 

2. Effluent from 

STP 

3. Erosion & 

Siltation 

Thrice a 

year 

pH, BOD, COD, TSS, TDS Once 

every 

month 

Soil erosion rates, stability 

of bank embankment, etc. 

4. Ecology Status of afforestation 

programmes 

5. Fisheries Phytoplanktons, 

zooplanktons, benthic life, 

Twice a 

year 

(Summer & 

postmonsoons) 

Once in 5 

years 

Twice a 

year 

Confluence Point of 

Tidding River and Lang 

River, Reservoir water, 

Parasuramkund, and 

downstream of the 

confluence of the tail race 

discharge. 

Before and after treatment 

from STP 

- 

- 

Confluence Point of 

Tidding River and Lang


S. 

No. 

Items to be 

monitored 

6. Incidence of 

water-related 

diseases 

7 Meteorological 

aspects 

8 Flow 

monitoring 



CISMHE 

fish composition River, Reservoir water, 

Parasuram Kund, and 

downstream of the 

confluence of the tail race 

discharge. 

Cause and control 

measures for various 

diseases. 

Temperature, rainfall, 

humidity, cloud cover, wind 

speed and direction 

Once in a 

year 

Project colony settlements 

within 2-3 km of the 

project site. 

Continuous Project office 

Discharge in river Lohit Continuous Just downstream of dam 

site


CISMHE 

16 

COST ESTIMATES 

16.1 COST FOR IMPLEMENTING ENVIRONMENTAL MANAGEMENT PLAN 

The total amount to be spent for implementation of Environmental Management 

Plan (EMP) is Rs. 26770.26 Lakhs. The details are given in Table 16.1. The cost 

is excluding of the following costs: 

• Land compensation as per the provisions of Land Acquisition Act 

• NPV towards forest land diversion 

• Cost of trees in forest area to be diverted 

Table 16.1: Cost for Implementing Environmental Management Plan 

S. No. Item of work Cost in Lakhs 

1 Catchment Area Treatment Plan 3312.00 

2 Reservoir Rim Treatment Plan 840.73 

3 Bio-diversity Conservation Plan 892.41 

4 Greenbelt Development Plan 91.45 

5 Landscaping & Restoration Plan 240.89 

6 Muck Disposal Plan 7000.00 

7 Fish Management Plan 456.33 

8 

Rehabilitation &Resettlement Plan and Local Area 

Development Plan including Public Health Delivery 

9 Public Health Delivery Plan 

9146.96 

Booked under R&R 

and LADP (1186.76) 

10 Subsidized Fuel Management Plan 229.00 

11 Solid waste management and sanitation facilities 128.58 

12 Disaster management plan 251.88 

13 Environmental Monitoring Plan 154.03 

14 Compensatory Afforestation 4000.00 

Grand Total 26744.26 

Environmental Management Plan – Cost Estimates 

16-1

EMP Chapter 9-16 - Arunachal Pradesh State Pollution Control ...

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