Transcript Document

Uncoordinated Management of
Karnafuli River Basin
5 World water Forum
Session 6.2.3
Emaduddin AHMAD, PEng.
Executive Director, Institute of Water Modelling
21 March, 2009
1
Management of Karnafuli River Basin
Total basin area: 12,500 sq. km. (approx.)
INDIA
Creation of
two lakes
after 1962
Lake area:
780 sq.km.
Kaptai Hydro
Power Plant
3500cumec
2
Chittagong
3
Hydropower
Flood alleviation
4,000
80% inflow in monsoon
66% release in monsoon
3,500
Flow augmentation
Inflow & Release (MCM)
3,000
2,500
Salinity control
2,000
WTP
1,500
PowerPlant
City
1,000
Port
PowerPlant
500
0
Feb
Mar
Apr
May
jun
Average Inflow
4
Paper &
Rayon mill
F. Factory
Jan
Jul
Aug
Average Release
Navigation
Sep
Oct
Nov
Dec
Kaptai dam
Current practice and issues in Karnafuli Basin management
115
36
34
35.97
35.05
35.05
34.14
32.92
32.31
32
31.09
30
29.87
29.57
28
28.35
27.74
26
25.91
24
Jan
Feb
Mar
Apr
May
Jun
Highest allow able w ater level
Jul
Aug
Sep
Oct
Nov
Dec
Low est allow able w ater level
After 46 years of operation
110
Reservoir Level, Ft (MSL)
Reservoir level m , PWD
38
105
100
95
90
85
Upstream issues
80
75
70
Nov-94
Baghaichari
Jan-95
Feb-95
Apr-95
May-95
Jul-95
Sep-95
Oct-95
Dec-95
Feb-96
Coumputed Reservoir Level
Recorded Reservoir Level
Downstream issues
Nannerchar
Existing
Lowest Reservoir LevelLangadu
Max Allowable Level
Fringe area
Flood-free environment and
inundation / drying
Water quality adequate irrigation water
Rangamati
Cooling
water
Barkal
WTP
depth
Water availability
PowerPlant
Additional Power
generation
PowerPlant
Paper &
Kaptai dam
Rayon mill
Salinity control
Water flow for effluent
discharge and navigation
Rule curve for reservoir operation
Drainage
potential City
Port
Siltation
F. Factory
5
Optimum dam release and sustainable river flow can resolve many of these
issues. Mathematical models provide required analytical basis in an integrated
way to make appropriate decisions.
Salinity level at the Mohra Water Treatment Plant
12000
January-March, 2007
10000
Chloride (mg/l)
8000
Allowable limit: 600 mg/l
6000
4000
2000
0
29-Dec-06
08-Jan-07
18-Jan-07
28-Jan-07
Raw (min)
07-Feb-07
17-Feb-07
Raw (max)
27-Feb-07
Treated (min)
09-Mar-07
19-Mar-07
29-Mar-07
Treated (max)
Causes of Salinity Build-up at Halda outfall (Mohara)
Decrease in freshwater flow from upstream
High tide level
6
08-Apr-07
Kaptai dam
Paper &
Rayon mill
WTP
Power Plant
City
Power Plant
Port
F. Factory
Mohra Water Treatment Plant experienced highest
level of salinity (up to 11500 mg/l in place of the
general range of <600 mg/l) in 2007, spawning is
lost for a very special type of carp
7
Adverse effect of uncoordinated dam release
•Salinity at Mohora Treatment Plant rose to 12000 ppm
resulting closure of treatment plant causing enormous
suffering to people of port city
•The rare species of carp at Halda (requiring specific level of
salinity) has been disappearing since last few years
All these require an ensured supply of fresh water
from reservoir during January to April (even by resheduling
the power generation – but it did not happen)
Similar event occurred this year due to release of flow in
earlier months with no regards for urban water supply. An
institution to negotiate with appropriate tool is absent.
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Reservoir Operation Model
A Decision Support System (DSS) for Optimum Reservoir Operation
Main Interface of ROM
Input
ROM
Elevation-storage curve
Output
Lake water level
Rule curves
A comprehensive database
of all hydrological, reservoir
and powerhouse data
Spillway release
Tail rating curves
A GIS interface for
generating inundation maps
Turbine release
Rainfall
A reservoir inflow prediction
model
Database
Generation
Inflow prediction
Evaporation
Initial lake water level
Power house data
Integration of the tools
to build a Decision
Support System (DSS)
for reservoir operation
Tail water level
Simulation
Inundation map of lake
Result presentation
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Reservoir Operation Model
Result presentation module
1
10
2
Reservoir Operation Model
Inundation mapping module
Operation dependent land
availability
Helped to build confidence in ethnic groups
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Conclusion
Salinity rise at Mohra or irrigation water
shortage at halda/Ichamoti is only due to
absence of basin level planning and
operation.
A River Basin Organisation (RBO) can be a
suitable platform to implement IWRM.
How to work with agencies having diversified
ineterst and chain of command
12
Institutional Need
Institution required for
• Equitable participation of stakeholders
• Output dissemination
• Participatory planning
• Sharing knowledge/constrain
Tour operator
Flood map
Fisheries and navigation
Water level and Extent
Upstream farmers
Flood map
IWM
Feedback & update
Public representatives/
NGO/Local administration
Industries
Tail water level
BWDB
Reservoir release
Tail water level
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BPDB
Inflow forecast,
Spillway release,
Flood map
Tail water level
Flood map
Institutional Framework
Water Resource Planning
Organization
River Basin Unit
Downstream stakeholder
committee
DSS housed at PDB, Kaptai
Upstream stakeholder
committee
Initial setup of RBO under WARPO with DSS is being
worked out
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