Impacts of water level changes in the fauna, flora and physical properties over the Balkhash Lake watershed

Abstract

The water level variations of the Lake Balkhash, the Kapshagay Reservoir and the Ili River and the linkage with salinity and biological conditions are investigated in this work using different techniques: satellite radar altimetry, in situ gauges, historical archives of fish population counting and field works. We show that it is possible now to monitor, over decades, in near real time, with high precision, the water level changes in the Lake Balkhash from satellite altimetry, over the reservoir and also along the Ili River. The vulnerability of the lake fauna and flora populations is enhanced by the morphometry of the lake: shallow and separation of the eastern basin from the western basin through the narrow Uzun‐Aral strait. Water policy of the Ili River also plays a fundamental role in the evolution of the Balkhash Lake. The Ili River that provides 80% of the surface water of the lake is a transboundary river. Development of intense irrigated agriculture in the upstream part of this river, located in the Chinese territory, could lead in the future to high hydrological stress in the downstream regions with potentially high damage in the delta and for fishery production. We show here the recent evolution of the Lake Balkhash basin from satellite data. Some interannual oscillation of 6–8 years over the last decade has been highlighted, with a water level of the lake still at a high value, but prediction on increasing irrigation is also highlighting the vulnerability of this lake. Linkage between water level change along the river and the downstream waters is also investigated. It shows that the role of the reservoir is not fundamental in the understanding of the Lake Balkhash water level changes which is in contrast highly correlated to upstream river level changes.

Evaluating Vulnerability of Central Asian Water Resources under Uncertain Climate and Development Conditions: The Case of the Ili-Balkhash Basin

“…This is confirmed by the observed gradual degradation of Ili Delta vegetation in the last 20 years [23]. Interestingly, the water level of Lake Balkhash has remained stable over the past decades [64][65][66], except for a rapid drop of the lake's water levels between 1970 and 1990 to the lowest recorded in 1987 as a result of reduced water availability during the filling of the Kapchagay reservoir [5,61,62,66]. This suggests that except for a sudden reduction in flows, the ecosystem has the capacity to absorb natural high and low flow shocks.…”

“…This suggests that except for a sudden reduction in flows, the ecosystem has the capacity to absorb natural high and low flow shocks. An explanation currently under investigation is the buffering capacity of the extensive river delta water surfaces and groundwater dynamics (8000 km 2 ); remote sensing studies indicate that the surface area of small ponds and lakes in the delta fluctuate according to Ili flow conditions [9,64].…”

Spatial-Temporal Change Analysis for Multivariate Drought Risk Based on Bayesian Copula: Application to the Balkhash Lake Basin

“…The lake stretches from east to west over 600 km, and width of the lake is 9-19 km in the eastern part and 74 km in the western part. The surface area of Balkhash Lake is fluctuant which ranges 17,000-22,000 km 2 , and the average depth of the lake is 6 m (Isbekov et al, 2019). The supplement of lake water consists of surface runoff, precipitation and groundwater, among which the main volume of water flowing is supplied by the river runoff (over 70%).…”

Quality of Drinking Water in the Balkhash District of Kazakhstan’s Almaty Region

“…Given the harshness of the environment and lack of water, it is not surprising that the 37,400 km 2 Balkhash District contains just 30,700 inhabitants who live mainly in 34 settlements near lakes and streams. The region's economic activity emphasizes pasture-based animal husbandry, recreational and commercial fishing, and extraction of minerals, and it is based on maximum exploitation of water and other natural resources [24][25][26][27]. Due to the extremely arid climate and high energy costs, irrigation for agriculture is only possible in two small gravity-fed areas near the Ili River (Figure 1).…”

“…The district's water infrastructure is recognized to be inadequate and largely outdated [8,17,28,29]. Summer water shortages often occur, but in contrast to the attention given to surface water and related environmental concerns [17,18,22,27,[30][31][32][33], little is known about the quality of drinking water available to residents. The sources and quality of drinking water in nine representative villages of the Balkhash District are consequently examined here for the first time with the goal of assessing potential risks to public health.…”