Abstract
The geologically complex Kyzylzharma groundwater field is located in the south-central part of Kazakhstan in the lower Syr Darya Basin.It supplies the 243,000 population of Kyzylorda City by drinking and agricultural water needs.Numerical modeling was used to predict the consequences of increased groundwater withdrawal for future water supply needs.The results displayed a mean squared error for the groundwater simulations of about 0.6 m and was thus acceptable.The validated transmissivity was between 2 Â 10 -7 and 2 Â 10 -5 m/d.These parameters showed that the planned groundwater withdrawal will result in a depression cone reaching 90-100 m below present levels in 2040.Maximum groundwater level drawdown may reach 130 m below present levels.This drawdown increases risks for brackish saltwater intrusion into the main groundwater aquifer.The results point at the depletion of groundwater resources in the Syr Daria Artesian Basin and the risks for groundwater quality, particularly increase in mineralization.The key outcome is the recognition that effective joint management of the Syr Daria Artesian Basin's groundwater resources, involving both Kazakhstan and Uzbekistan, necessitates development and operation of a joint numerical aquifer model.Building this model is a crucial tool for assessing the sustainable groundwater resources in the region.