Development of Groundwater Modeling Capacity in Mongolia: Keys to Success

Abstract:

Ulaanbaatar, the capital city of Mongolia, is totally dependent on groundwater for its municipal and industrial water supply. Water is drawn from a network of shallow wells in an alluvial aquifer along the Tuul River. Evidence, however, suggests that current water use and especially the projected water demand from a rapidly growing urban population, is not sustainable from existing water sources. In response, the Mongolia Ministry of Environment and the Mongolian Fresh Water Institute requested technical assistance on groundwater modeling through the U.S. Army Corps of Engineers to the U.S. Geological Survey (USGS). Scientists from the USGS-SD Water Science Center provided a workshop to Mongolian water experts on basic principles of groundwater modeling using MODFLOW. The purpose of the workshop was to bring together representatives from the Government of Mongolia, local universities, technical experts, and other key stakeholders to build in-country capacity in hydrogeology and groundwater modeling. A preliminary steady-state groundwater flow model was developed to simulate groundwater conditions in the Tuul River Basin and for use in water use decision-making. The model consisted of 2 layers, 226 rows, and 260 columns with uniform 500 meter grid spacing. The upper model layer represented the alluvial aquifer and the lower layer represented the underlying bedrock, which includes areas characterized by permafrost. Estimated groundwater withdrawal was 180 m³/day, and estimated recharge was 114 mm/yr. The model will be modified and updated by Mongolian scientists as more data are available. Ultimately the model will be used to assist managers in developing a sustainable water supply, for current use and changing climate scenarios. A key to success was developing in-country technical capacity and partnerships with the Mongolian University of Science and Technology, Mongolian Freshwater Institute, a non-profit organization, UNESCO, and the government of Mongolia.