Mekong River Commission


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Decision Support Framework

System components

The DSF has been developed through a process of consultation involving all four National Mekong Committees and line agencies from each country. The system comprises three main elements accessed through a single user-interface:

  1. a Knowledge Base containing information on the historical and existing resources and, when fully populated, socio-economic and environmental conditions, as well as predictions of how these may change in the future
  2. a suite of Simulation Models that enable the prediction of impacts of changes in conditions within the basin on the river system, and
  3. a set of Impact Analysis Tools that enable the prediction of environmental and socio-economic impacts in response to changes in condition of the river system


Background Technical Reference Reports have been prepared for each component of the system that record how each has been developed and tested.


 
DSF Introduction
• System Components
Using the System
System Maintenance
 

User Interface

Access to the DSF is through the main interface, with menus to guide the user through the entire system (according to user access rights set by the Administrator). A context-sensitive Help function is provided with direct links to a suite of User Guides. The main user interface can be easily customised to provide user-defined views.

Knowledge Base
The Knowledge Base contains the core data, pre-defined models (new model configurations can be set up by the Specialist Modellers and loaded into the Knowledge Base), selected outputs from the model simulations and the results of analyses conducted with the Impact Analysis Tools. The Knowledge Base is flexibly structured to allow new information to be added.
Data held in the Knowledge Base are listed in the on-line data catalogue. Meta data records the sources and status of all the information held. The core data have been drawn principally from the MRCS Databases, with some directly from individual country sources. All KB data can be readily exported.

Hydrological Models
Three basic types of model have been developed for the DSF. A series of hydrological models, based on the SWAT software of US Department of Agriculture, have been set up to simulate 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.

Basin Simulation Models
The hydrological models provide inputs to a series of basin simulation models that are based on the IQQM 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. 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. The IQQM software also draws from data in the Knowledge Base to estimate irrigation demands throughout the LMB in a consistent manner.

Hydrodynamic Models
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. Typically it generates hourly data for water levels and discharges throughout the main channels and distributaries in the delta. A salinity intrusion model has also been set up with the ISIS software drawing on the results of the hydrodynamic model. ISIS also has capability to simulate other water quality parameters, including sedimentation, but at present there are insufficient data to warrant setting up these models.
Each model is run from the DSF interface with data automatically transferred from one to another through the Knowledge Base. A number of adjustments to the models that do not involve reconfiguring the model are also possible through the DSF interface (such as varying demands and climate). Guidelines for using the modelling software are provided in the software manuals, and on operating the DSF interfaces in the DSF User Guides.
Results from the model simulations are stored in the Knowledge Base for further investigation using the suite of Impact Analysis Tools.

Impact Analysis Tools

Guidance on when and which impact analyses tools to select and on their application is provided in separate reports.

Each tool has been specifically developed so that the full range of environmental and socio-economic indicators can be investigated.

In the case of the spatial analyses, information derived from the mapping tools can be overlain on any range of appropriately formatted spatial data using ArcView (provided with the DSF) to make direct assessments of impacted populations, land areas or sites of specific interest.

The basic models have been calibrated and the results are given in the Technical Reference Reports. These provide a clear indication of the confidence that can be expected in the projections made with the models. The DSF system has been tested and evaluated as a whole, and this is reported. A Hydro-Ecological Report provides good examples of how the DSF can be used to provide considerable insight into the characteristics and behaviour of the river basin.

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