An alternative water supply in an increasingly desertified region
The Aral Sea located in central Asia was the fourth largest inland lake in the world prior to 1960. However, increasing diversion of water from the rivers that feed the Aral Sea for irrigation purposes has decreased both its volume and surface area by over 50%. The loss of freshwater input has initiated the desertification process in the region as the water level retreats and former seabed is exposed. The lake's salinity has also experienced a threefold increase, posing a severe threat to the local ecosystem. Furthermore, the continental climate, previously moderated by the presence of the lake, has become increasingly harsh. In short, the Aral Sea is a multifaceted environmental disaster. The problem crosses national boundaries as the irrigation occurs far upstream in the Amu Darya and Syr Darya rivers. The INTAS Programme of the European Union gathered scientists from Independent States of the former Soviet Union in this region as well as from Europe to address the crisis. One of the many problems the local population is facing is the contamination of their drinking water supply. High concentrations of toxic pollutants found in water samples likely derived from irrigation runoff, pesticide application and other activities related to the intense agricultural activity in the region. A number of research projects were designed to cover both measurement and modelling needs. Hydrometeorological, hydrological and hydrogeological data were gathered from the rivers, local aquifers as well as the Aral Sea itself. Assessment of the situation was aided by the use of numerical models. The results of the exercise indicate the feasibility of satisfying the region's potable water needs with subsurface sources, i.e. groundwater. Use of groundwater is nothing new and frequently implemented in arid regions where quantities of high quality surface water are minimal. The comprehensive approach applied during the project will help avoid traditional disadvantages associated with groundwater, such as subsidence. Future research will answer lingering questions, such as possible contamination of available groundwater resources by saline infiltration. In addition, analysis of various mitigation strategies will allow the participants to guide the region toward slowly reversing the ecological catastrophe.