WHAT IS THE WHAT IS THE Decision Support Framework (DSF)Decision Support Framework (DSF)

1. What is a Decision Support Framework?

A suite of computer models linked to a databaseA suite of computer models linked to a database

Simulates behaviour of the LMB river systems under Simulates behaviour of the LMB river systems under

different development conditions…different development conditions…

Assists prediction of environmental and socio-Assists prediction of environmental and socio-

economic impacts caused by flow and water quality economic impacts caused by flow and water quality

changeschanges

Key functions of the DSFKey functions of the DSF

Predict how the river system will behave under Predict how the river system will behave under different future development scenarios different future development scenarios

Assess what impacts are likely to occurAssess what impacts are likely to occur

Undertake these analyses in a manner that is Undertake these analyses in a manner that is transparent and acceptable to alltransparent and acceptable to all

Use of the DSF for Basin PlanningUse of the DSF for Basin Planning

Investigate management options that best Investigate management options that best achieve policy objectivesachieve policy objectives

Analyse likely transboundary impactsAnalyse likely transboundary impacts

Audit compliance with:Audit compliance with: National policy objectivesNational policy objectives Acceptable impact levels &Acceptable impact levels & Mekong Agreement flow rulesMekong Agreement flow rules

Examples of what the DSF can look at ?Examples of what the DSF can look at ?

Land management practices:Land management practices: Change in catchment runoff factorsChange in catchment runoff factors

Reservoirs Reservoirs (including hydropower)(including hydropower):: New reservoirs in ChinaNew reservoirs in China New reservoirs in LMBNew reservoirs in LMB Changes in operation of existing reservoirsChanges in operation of existing reservoirs

Flood protection (d/s Kratie):Flood protection (d/s Kratie): New embankments and roadsNew embankments and roads Raised embankments and roadsRaised embankments and roads

Channel improvements (d/s Kratie):Channel improvements (d/s Kratie): Dredging and re-profilingDredging and re-profiling Cross-regulation Cross-regulation Salinity intrusion barriersSalinity intrusion barriers

What are the 3 models that make up the What are the 3 models that make up the DSFDSF

A hydrologic model (SWAT)A hydrologic model (SWAT) A river simulation model (IQQM)A river simulation model (IQQM) A hydrodynamic model (ISIS)A hydrodynamic model (ISIS)

What do these models look like ?What do these models look like ?

SWAT!SWAT! The rainfall-runoff model (hydologic model) The rainfall-runoff model (hydologic model)

covers covers allall the hilly areas – no gaps! the hilly areas – no gaps! Each sub-basin is like a leaf on a tree which Each sub-basin is like a leaf on a tree which

collectscollects water water

I’m a SWAT sub-basin

The IQQM river simulation model joins the The IQQM river simulation model joins the SWAT sub-basins togetherSWAT sub-basins together It collect the water from the leaves and It collect the water from the leaves and

shows how that water moves down the shows how that water moves down the riverriver

… …to my roots – to my roots – ISISISIS, , the hydrodynamic the hydrodynamic modelmodel ……which spread out which spread out

wide across the wide across the floodplainfloodplain

SWAT sub-basins collect SWAT sub-basins collect water & WQ parameterswater & WQ parameters

IQQM models the flow down IQQM models the flow down the river branches…the river branches…

iSIS hydrodynamic model iSIS hydrodynamic model moves the water in 2 moves the water in 2 directions across the directions across the floodplainfloodplain

KRATIE

Coast

China inflows

Location of SWAT sub-basins relative to Location of SWAT sub-basins relative to potential damspotential dams

Location of irrigation demand nodes in Isan Location of irrigation demand nodes in Isan ProvinceProvince

Area covered by Area covered by the the hydrodynamic hydrodynamic modelmodel

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Kratie

Prek Dam

Koh Khel

Neak Luong

Kompong Cham

Kampong Luong

Phnom Penh Port

Kampong Chhnang

Takmay (Chatomouk) Phnom Penh

2001 Calibration Points for iSIS model

Temporary Gauges

Permanent Gauge Sites#

Extra Gauges in Cambodia 2002

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Kratie

Phnom Penh

Hydrodynamic Hydrodynamic model node model node structurestructure

Things to remember about using the DSFThings to remember about using the DSF

Each type of model takes different lengths of time to Each type of model takes different lengths of time to run – the Hydrodynamic model takes the longest – run – the Hydrodynamic model takes the longest – about 40 minutesabout 40 minutes

Modellers often come back wanting changes usually Modellers often come back wanting changes usually they need to simplify the analysisthey need to simplify the analysis

Saving the results to the DSF takes additional time – Saving the results to the DSF takes additional time – perhaps as long as it takes to run the modelsperhaps as long as it takes to run the models

The more you ask for (locations, short time-steps) the The more you ask for (locations, short time-steps) the longer they take to run and to save to the DSFlonger they take to run and to save to the DSF

The volumes of data are large – the DSF models & The volumes of data are large – the DSF models & results for 8 scenarios currently use 5 GBresults for 8 scenarios currently use 5 GB

What can the DSF tell us ?What can the DSF tell us ?

Two examples are:Two examples are: Flow information – how the volume of flow Flow information – how the volume of flow

might change if there is some interventionmight change if there is some intervention Spatial information – what changes in flow in Spatial information – what changes in flow in

the Mekong delta might look like if there is the Mekong delta might look like if there is some interventionsome intervention

For example - What ifFor example - What if irrigation irrigation increases? increases?

If there is an extra 0.5 million ha of dry If there is an extra 0.5 million ha of dry season irrigation upstream of Kratie.....season irrigation upstream of Kratie.....

Kratie Annual Minimum Flows of Scenario 4Vs base line

800

1000

1200

1400

1600

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2000

2200

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Year

Q (m3/s)BL min SCN min BL avg. min SCN avg. min

Flows at Kratie would changeFlows at Kratie would change??

Current min flow at Kratie

Min flow with extra irrigation

Annual minimum flows at Kratie

DRAFT

What if there are changes in flow as the result What if there are changes in flow as the result of dams ? – such as the dams in Chinaof dams ? – such as the dams in China

The DSF can provide spatial dataThe DSF can provide spatial data

Flood depths Flood depths might change might change as a result of as a result of the Chinese the Chinese damsdams

Flood Flood durations may durations may change as a change as a result of the result of the Chinese damsChinese dams