MRC DSF/ Toolbox Model (SWAT, IQQM, ISIS)

Basin Simulation Modelling Package for MRC decision support frameworks using for prediction of impacts of changes in conditions within the basin on the river system compose of SWAT, IQQM and iSIS model.

More Information on MRC Model


Figure 1: Area inside the Lower Mekong Basin to which three simulation models have been applied
  • The SWAT developed by the United States Department of Agriculture has been set-up to generate subbasin runoff from rainfall and climate data then provide inputs to a series of basin simulation models.
  • The basin simulation models are based on the Integrated Quantity and Quality Model software originally developed for the Murray-Darling Basin in Australia. The simulation models route catchment flows through the river system, making allowance for control structures such as dams and irrigation abstractions.
  • A hydrodynamic model, based on iSIS software developed by HR Wallingford and Halcrow, is used to simulate the river system downstream part of the basin including Great Lake and Delta. The hydrodynamic model represents the complex interactions caused by tidal influences, flow reversal in the Tonle Sap River and over-bank flow in the flood season with the varying inflows from upstream.


Figure 2 : SWAT model in Mekong River Basin

Hydrological Model: Soil Water & Assessment Tool (SWAT)

SWAT is a simulation catchment runoff based on estimates of daily rainfall and the topography, soils and land cover of each sub-basin.

The SWAT software has the capability to investigate nutrient and sediment flows also, but there are insufficient data to establish calibrated models for these at present. Within the Lower Mekong Basin (LMB), the catchment is divided into different sub-basins to simulate this runoff according to hydrological condition and its reference station.




Figure 3 : IQQM model in Mekong River Basin

Basin Simulation Model: Integrated Quantity and Quality Model (IQQM)

The Integrated Quantity and Quality Model used output from SWAT sub-basins to route through the river system, making allowance for control structures such as dams and irrigation abstractions.

Information on daily discharges are generated throughout the system and particularly at the primary outfalls of Kratie on the mainstream and the Great Lake in the Tonle Sap basin including Mekong Delta near river mouth.




Figure 4: Schematic of iSIS model using in Cambodia Flood plain and Mekong Delta

Hydrodynamic Model - ISIS

A hydrodynamic model, based on ISIS software, is used to simulate the river system downstream of Kratie, including the Tonle Sap and the East Vaico in Viet Nam where wet season flooding extends beyond the LMB boundary.

The hydrodynamic model represents the complex interactions caused by tidal influences, flow reversal in the Tonle Sap River and over-bank flow in the flood season with the varying inflows from upstream. Such complexity cannot be modelled by simple routing models.

The hydrodynamic model thus uses outputs from the IQQM model for upstream flows under different scenarios, direct runoff from local catchments modelled using SWAT and irrigation water use modelled using IQQM. Salinity is also modelled using the hydrodynamic model.