11

Uncoordinated Management of Karnafuli River Basin

Emaduddin AHMAD, PEng.

Executive Director, Institute of Water Modelling21 March, 2009

5 World water ForumSession 6.2.3

22

Management of Karnafuli River Basin

Total basin area: 12,500 sq. km. (approx.)

I N D I A

Kaptai HydroPower Plant

Creation of two lakes after 1962Lake area: 780 sq.km.

3500cumec

33

Chittagong

44

Paper &Rayon mill

Port

City

F. Factory

WTP

Kaptai dam

PowerPlant

PowerPlant

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

Jan Feb Mar Apr May jun Jul Aug Sep Oct Nov Dec

Infl

ow

& R

elea

se (

MC

M)

Average Inflow Average Release

80% inflow in monsoon66% release in monsoon

Hydropower

Flood alleviation

Flow augmentation

Salinity control

Navigation

Hydropower

Flood alleviation

Flow augmentation

Salinity control

Navigation

55

Paper &Rayon mill

Port

City

F. Factory

WTP

Kaptai dam

PowerPlant

PowerPlant

Rangamati

Nannerchar Langadu

Barkal

Baghaichari

Current practice and issues in Karnafuli Basin management

Fringe area inundation / drying

Water flow for effluent discharge and navigation

Water availabilityAdditional Power generation

Cooling water depth

Salinity control

Water quality

Flood-free environment and adequate irrigation water

Siltation

Drainage potential

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.

34.14

32.3131.09

29.57

27.74

25.91

28.35

29.87

32.92

35.0535.97

35.05

24

26

28

30

32

34

36

38

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Re

se

rvo

ir le

vel m

, PW

D

Highest allow able w ater level Low est allow able w ater level

Rule curve for reservoir operation

Upstream issues

Downstream issues

After 46 years of operation

70

75

80

85

90

95

100

105

110

115

Nov-94 Jan-95 Feb-95 Apr-95 May-95 Jul-95 Sep-95 Oct-95 Dec-95 Feb-96

Res

ervo

ir L

evel

, F

t (M

SL

)

70

75

80

85

90

95

100

105

110

115

Nov-94 Jan-95 Feb-95 Apr-95 May-95 Jul-95 Sep-95 Oct-95 Dec-95 Feb-96

Res

ervo

ir L

evel

, F

t (M

SL

)

66

Salinity level at the Mohra Water Treatment Plant

Causes of Salinity Build-up at Halda outfall (Mohara)Decrease in freshwater flow from upstreamHigh tide level

0

2000

4000

6000

8000

10000

12000

29-Dec-06 08-Jan-07 18-Jan-07 28-Jan-07 07-Feb-07 17-Feb-07 27-Feb-07 09-Mar-07 19-Mar-07 29-Mar-07 08-Apr-07

Ch

lori

de (

mg

/l)

Raw (min) Raw (max) Treated (min) Treated (max)

January-March, 2007

Allowable limit: 600 mg/l

77

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

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

Paper &Rayon mill

City

F. Factory

Port

Kaptai dam

Power Plant

Power Plant

WTP

Paper &Rayon mill

City

F. FactoryF. Factory

PortPort

Kaptai dam

Power Plant

Power Plant

WTPWTPHalda

88

Adverse effect of uncoordinated dam releaseAdverse effect of uncoordinated dam release

•Salinity at Mohora Treatment Plant rose to 12000 Salinity at Mohora Treatment Plant rose to 12000 ppm resulting closure of treatment plant causing ppm resulting closure of treatment plant causing enormous suffering to people of port cityenormous suffering to people of port city

•The rare species of carp at Halda (requiring specific The rare species of carp at Halda (requiring specific level of salinity) has been disappearing since last few level of salinity) has been disappearing since last few yearsyears

All these require an ensured supply of fresh waterAll these require an ensured supply of fresh waterfrom reservoir during January to April (even by from reservoir during January to April (even by resheduling the power generation – but it did not resheduling the power generation – but it did not happen) 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.

99

Reservoir Operation ModelA Decision Support System (DSS) for Optimum Reservoir

Operation

A comprehensive database of all hydrological, reservoir

and powerhouse data

A GIS interface for generating inundation maps

A reservoir inflow prediction model

Integration of the tools to build a Decision

Support System (DSS) for reservoir operation

ROM

Elevation-storage curve

Rule curves

Rainfall

Evaporation

Input

Initial lake water level

Power house data

Tail rating curves

Output

Lake water level

Spillway release

Generation

Tail water level

Inundation map of lake

Turbine release

A comprehensive database of all hydrological, reservoir

and powerhouse data

A GIS interface for generating inundation maps

A reservoir inflow prediction model

Integration of the tools to build a Decision

Support System (DSS) for reservoir operation

ROM

Elevation-storage curve

Rule curves

Rainfall

Evaporation

Input

Initial lake water level

Power house data

Tail rating curves

Elevation-storage curve

Rule curves

Rainfall

Evaporation

Input

Initial lake water level

Power house data

Tail rating curves

Output

Lake water level

Spillway release

Generation

Tail water level

Inundation map of lake

Turbine release

Output

Lake water level

Spillway release

Generation

Tail water level

Inundation map of lake

Turbine release

Database Inflow prediction

Simulation

Result presentation

Main Interface of ROM

1010

11 22

Reservoir Operation Model

Result presentation module

1111

Operation dependent land availability

Helped to build confidence in ethnic groups

Reservoir Operation Model Inundation mapping module

1212

ConclusionConclusion

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

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Institutional NeedInstitutional Need

Institution required forInstitution required for

• Equitable participation of stakeholdersEquitable participation of stakeholders

• Output disseminationOutput dissemination

• Participatory planningParticipatory planning

• Sharing knowledge/constrainSharing knowledge/constrain

Public representatives/NGO/Local administrationFlood map

Upstream farmersFlood map

IndustriesTail water level

BWDBReservoir releaseTail water level

BPDBInflow forecast, Spillway release,Flood mapTail water level

IWMFeedback & update

Fisheries and navigationWater level and Extent

Tour operatorFlood map

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Institutional Framework

Water Resource Planning Organization

DSS housed at PDB, KaptaiRiver Basin Unit

Upstream stakeholder committee

Downstream stakeholder committee

Initial setup of RBO under WARPO with DSS is being worked out

1515