Runoff response to the glacier shrinkage in the Karatal river basin, Kazakhstan

The fresh water lack in Central Asian countries with fast-growing population is one of the most critical problems in this region, where runoff of most rivers closely depends on supply of glaciers melting water. However, the impact of glacier shrinkage on the river runoff remains poorly understood. In this paper, we took the Karatal river basin, Tien Shan, as a model for investigation interrelation between dramatic decreasing of glaciers (-1 % annually) and river runoff. We investigated long-term observed climatic and runoff data for different sub-basins of the river, having various glaciated area and used non-parametric Mann-Kendall test for our analyses. Analyzing weather station climatic data, we found a significant increase in temperature and quite stable trends for precipitation during study period. Positive trends in annual discharge were detected in almost all glacierized tributaries of Karatal river. This obvious upward trend in river runoff is likely connected with a general trend of increasing temperatures and intensive melting of glaciers in Tien Shan.