PACKAGE : I Bid Document VOLUME : II - Public Health Engineering

vii) This region has experienced a large number of major earthquakes during the last
century. The area where the above intake is proposed to be built lies within the Iso-cysmal
VIII-IX in the modified Barcelli Scale. Seismicity of the region is an important factor to be
considered for the design of the Intake structure and other appurtenant works.
viii) Minimum storage capacity of Intake well shall be 30 minutes storage at the lowest
level of water in the reservoir and at average rate of pumping for 20 hours operation of
pumps in a day to supply 24 MLD.
ix) There will be 3 Nos. of inlet port sluice valves, which shall be of manually operated
non-rising spindle type CIDF as per IS: 3042. The spindle of the sluice gate shall be of
stainless steel and additional length of Stainless Steel spindle shall also be provided with
intermediate line support bearing of phosphor bronze sleeve in CI casing at a regular
interval of maximum 1.5 m shall be provided for operation of the sluice gate from top at
the pump floor level. Diameter of the spindle shall be sized such that tensional deflection is
restricted below 0.25 degree/m length. Operational arrangement shall be essentially be
made with bevel gear and head stock assembly for easy operation by one person.
x) The intake structure shall be circular in shape and sizes of the same shall also be
determined by the following conditions:
RL of high flood level : 1577.00m
RL of lowest water level : 1562.00m
In order to keep the operating floor free from obstruction and pipe work,
delivery is to be taken below the pump floor level i.e. at RL 1583.20m, 2.40m
below the pump floor level which is at RL 1585.60m and 8.6m above the high
flood level in keeping the same level with the existing intake structure
The depth of the Intake well is to be considered taking into consideration the
minimum water depth required upto minimum WL to satisfy NPSHR for VT
Pump to avoid air entry during drawdown.
Provision for prevention of vortex formation.
Provision for obtaining uniform distribution of the in-flow to all the operating
pumps and to prevent starvation of any pump.
16.5 For design of intake pump house. The following factors are to be
considered:
i) The pump house shall be square and shall be constructed above the Intake well.
The floor of Pump House and discharge pipe floor with RCC beams shall be constructed to
withstand the load of 6 (six) numbers of Pumps, Motors, Column Pipes, Delivery Pipes,
Valves and other electrical accessories, H.O.T. crane etc. as well as part of the load coming
from the Approach steel bridge which shall rest on the floor at one end. The pump floor
and RCC beams shall be M-25 concrete and HYSD/TMT bars (Fe - 415). The walls of the
Pump House shall be 250 mm thick 1 st class brickwork with 1:4 cement mortar (1cement
and 4 sand). Adequate numbers of RCC columns along the centre line of periphery of the
DTS : Detailed Tender Specification. Page 159