Challenges of the groundwater management in Can Tho City ... - BGR

Challenges of the Groundwater
Management in Can Tho City,
Vietnam
Thomas Nuber
Harro Stolpe
BGR- Symposium
Sanitation and Groundwater Protection
14.10.-17.10.2008
Hannover
Environmental Engineering + Ecology
Professor Dr. Harro Stolpe
Ruhr-University Bochum

SANSED-Project
- Closing Nutrient Cycles in Decentralized Water Treatment
Systems in the Mekong Delta, Vietnam
- 3 involved Universities
– Ruhr University Bochum, Germany
– University of Bonn, Germany (Coordinating)
– University of Can Tho, Vietnam
- 8 German private companies
- 2003 – 2008
- Funded by the Federal Ministry of Education and Research
of Germany (BMBF), PT FZ Karlsruhe
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Vietnam
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200 km
Can Tho
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Can Tho
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Can Tho
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Can Tho
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Sanitation in Vietnam
National
Rural Clean
Water
Supply and
Sanitation
Strategy up
to the Year
2020
(1998)
Vietnam
Developmet
Goals
(2001)
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2005 2010 2020
Water supply:
60 % (rural areas)
80 % (urban areas)
Rural Areas
85 % acess to a min. of
60 l/d*capita
70 % access to latrines
Water Supply:
80 % (rural areas)
85 % (urban areas)
Waste Water
Treatment of 100% of
the urban waste water
Rural Areas
100% acess to a min. of
60 l/d*capita
100% acess to latrines
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Sanitation
- Responsible Authorities
– Center of Rural Water Supply and Sanitation
(Department of Agriculture and Rural Development)
– Department of Health
- Concept
– Use of Septic Tanks
– Use of Groundwater as hygienically safe drinking water
resource
• Remote areas: Small scale tube wells
• Decentralized Water Treatment Plants
(Groundwater, Capacity 60 m³/d)
– VAC(B)-Modell
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Waste Water
from households
and farms
Septic tanks
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untreated into
canals
into fishponds
in biogas digesters
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Groundwater Use
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
10
177
310
220
270
110
130
326
400
230
140
210
170
1990
5970
2110
5980
2040
1040
2030
2060
2090
2170
2190
1880
2140
8080
2240
8220
80402
N
0 20 40 60 Kilometers
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
10
177
310
220
270
110
130
326
400
230
140
210
170
1990
5970
2110
5980
2040
1040
2030
2060
2090
2170
2190
1880
2140
8080
2240
8220
80402
N
0 20 40 60 Kilometers

Groundwater Use
Accessed HHs per supply station
396 ground water supply stations in Can Tho
Accessed to QII-III
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Groundwater supply stations per community
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Groundwater Use
32.000 known small scale tube wells in Can Tho
Depth 60 – 100 m below surface
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Small scale tube wells per km²
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Impacts on Groundwater Quality
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Infiltration through
leaking well casing
or missing sealing
Possible waste water infiltration
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Impacts on Groundwater Quantity
Growing Pressures on
Groundwater
- Rapid population and
economical growth
- Use of surface water for
waste water disposal
- Use of groundwater as a
safe source
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Level below Sea Level in m
2
1
0
-1
-2
-3
-4
Groundwater Resource
-5
Jan 95 Jan 96 Jan 97 Jan 98 Jan 99 Jan 00 Jan 01 Jan 02
Time
Well Q 211(QIV) Well Q 211(QII-III) Well Q 211(NII)
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Conclusions
QUALITY IMPACTS
- Good protection of main aquifer through the covering
layer
- Possible impacts on groundwater quality through wells
– Short cuts because of leaking well casings or missing sealing
– Use of „dry“ small scale tube wells for „waste water disposal“
reported
QUANTITY IMPACTS
- Lack of waste water treatment causes higher groundwater
abstraction
- Overexploitation of groundwater resources observed
– Rapid declining groundwater tables
– In 5 – 10 years use of GW through suction pumps not
possible anymore
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Approaches
- Implementation of decentralized waste water treatment
concepts (www.sansed.uni-bonn.de)
- Removal of small scale tube wells should include
sophisticated backfill and sealing
- Implementation of alternative drinking water treatment
methods
– rainwater storage,
– artificial groundwater recharge,
– slow sand filtration
- Coordinated groundwater monitoring concept
– Transboundary monitoring
– Monitoring of quantity and quality
- Introduction of an IWRM-Concept (www.iwrm.vn)
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Contact and more information
- Thomas Nuber
Federal Institute for Waterway Constructions
Bundesanstalt für Wasserbau, Karlsruhe
thomas.nuber@baw.de
- Harro Stolpe
Environmental Engineering and Ecology
Ruhr-University Bochum
harro.stolpe@rub.de
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Outline
- Introduction
- Investigation Area
- Sanitation in Vietnam
- Groundwater Use in Can Tho City
- Impacts of Sanitation on Groundwater Quantity
- Impacts of Sanitation on Groundwater Quality
- Conclusions
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Involved Private Companies
B 3
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Ith Ingenieurbüro für
technische Hydrologie
Thilo Herrmann
F+E Arbeitsgemeinschaft
Nachhaltige Aquakultur
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Vietnam in figures
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VN Germany
Population 80 Mio. 82 Mio.
Area 327 000 km² 357 000 km²
GDP 36,40
Billion Euros
2 168,82
Billion Euros
Economical Growth 8 % 1 %
Average Age 26 years 40 years
Climate
tropical - subtropical moderate
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Can Tho
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Idea of the Project
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Recycling of
nutrients
+
Water
Management
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Water sources utilised for drinking water
purposes
An Binh
58%
• 60 % use of Groundwater as drinking water
• General: use of different water sources in parallel
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22%
20%
Long Tuyen
60%
10%
30%
Rain water Surface water
Groundwater
(Wienecke, 2005)
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