Surface water and groundwater resources in the Tuul River Basin arc a vital resource in the socio-economic
situation and its development in Mongolia. Although the river rasin covers about 3.2 % Mongolian’s total land,
about 46.27 % o f Mongolian population lives in the river basin and most o f them, around 4 6 % live in
Ulaanbaatar. the capital city o t Mongolia. Ulaanbaatar is the highest water usage in the country, and water
supplies in the c ity completely dependent on an alluvial iloodplain groundwater (pumping wells) o f the Tuul
River. The river Iloodplain groundwater and river flow is hydraulically linked and the groundwater storage is
replenished by the river water. However, the river flow has been declined and run dry during low flow period
(early spring for 2-31 days) o ccasionally since 1997. We haven’t able to carry out sustainable water resources
management to protect freshwater biodiversity and sustain river flow for ecosystems in the Tuul River. Therefore,
in this region need to be improved water management more urgently to involve the impacts prediction during low
flow period (i.e.. spring and autumn). This research aims to understand impact o f climate change and groundwater
abstraction on the flow o f the Tuul River and provide some baseline data for sustainable water resources
managements o f Ulaanbaatar.