The Mekong river, twelfth longest river in the world originates from Tibet and has a total length of 4200 km and covers an area of 795 500 km2. It is the life-blood of Southeast Asia. Fed by melting snow on the Tibetan Himalayas and monsoon rains, the river nourishes millions of lives from Southern China, Burma, Laos, Thailand, and Cambodia to the delta in Vietnam. It covers all of the Lao PDR and Cambodia, a large part of Thailand, the delta and central highland in Vietnam.  According    Agreement on the Cooperation for the Sustainable Development of the Mekong River Basin On the 5th of April 1995.  The Mekong River
Commission (MRC) is an international river basin  organisation  built on a foundation of nearly 50 years of  knowledge and experience in the region., Cambodia, the Lao PDR, Thailand and Viet Nam.  

The main current modelling tools at MRCS, the DSF and the WUP-FIN tools, were developed and implemented within the Water Utilisation Programme (WUP) which lasted 2000-2006. The DSF was developed by the Halcrow Group consultants 2001-2004, with substantial involvement of riparian experts for data collection, checking and model set-up. International experts were trained to riparian  modellers through both formal training sessions and on-the-job training and since 2001 and they became the core modellers of MRCS. Decision Support Framework (DSF) has been developed by MRC/ Halcrow and Accepted in 2004.    The World Bank and MRCS support riparian state members (NMCs) in the application of DSF through application national case studies. In fact the MRC DSF was developed by Halcrow Group Ltd for the Mekong River Commission as extension part
of the Mekong Water Utilisation Programme (WUP).  

Ideally, the prime outputs of the MRC's Basin Development Plan should be a BDP Sub-area Scenario mapped for each province of Lao PDR  throughout the entire Nam Ou basin where existing  1L  and it    founded on land capability assessment, combined with demographic projection and socio-economic titling and so on.  

According of Component 4 of IKMP ‟s Work plan  2010 will further develop modelling tools that generate data and information for forecasting, decision making, planning and impact assessment.  Activities wall also focus on building the MRC‟s and the national capacities for problem analysis, model application and the provision of decision support
services.

During the year 2010, a    better improving skill modelers with Lao PDR using two case studies in the  nam Ou (1L) and  Xebanghieng (4L)  since  the year 2007  for capacity building.  At the moment, this basin is    a development of hydropower with seven hydropowers and  impacts of  drought and flood situations  on Sebanhieng basin  both they are critical problems so this year 2010 LNMC is agreed to update those case studies .  

Above study will use DSF model such as on the job training of ARCSWAT, it has been used for first time of LNMC Modelling team.
It has been being  the  lesson learn about    pre-process the spatial data for the river system. A brief description of the pre-processing has been given in the following section.