The flow regimes in the PMFM Technical Guidelines are analyzed using the MRC Basin Modelling and Knowledge Base which became known as the Decision Support Framework.
(approved at the 19th MRC Joint Committee Meeting in March, 2004 as an MRC analytical tool in support of Rules Formulation, Basin Development Plan and other MRC Programmes).
The Decision Support Framework (DSF) is a computer-based system comprising a suite of three integrated models (SWAT, IQQM and ISIS) representing at basin-scale simulation for the water resource system of the Lower Mekong Basin, underpinned by a knowledge base of input and output data, and a range of analytical and reporting tools to facilitate assessment of potential flow changes on environmental and social conditions.
The DSF is founded on 16 years (Baseline: 1985-2000) of hydrological and hydrometeorological records from throughout the LMB and uses these to predict changes that would occur with different development conditions in the basin arising from new infrastructure, additional abstractions, climate change and the like.
The DSF reports on the predicted simulated flow conditions at key hydrological stations in the mainstream and allows comparison of these with the Baseline Scenario (1985-2000) to determine the impact of different future development conditions. The DSF also includes capability to determine the impact of changed flow conditions on saline intrusion within the Mekong delta.
The Baseline Scenario is deemed sufficiently representative of the natural flow conditions occurring prior to 2000 as referred to in Article 6 of the 1995 Mekong Agreement. For planning purposes under the PMFM, it is necessary to compare simulated flows using the DSF with Baseline Scenario in order to establish whether the planned future development conditions are predicted to result in “acceptable” modifications to baseline flow conditions. The PMFM and its Technical Guidelines define what “acceptable” means and how it may be measured.
In contrast, when the PMFM is used for monitoring purposes, the intent is that the comparison is made between currently observed flows with historically observed flows at the selected hydrological stations, the historically observed flows being based on the longest reliable set of flow records available at those stations.