The Amu Darya delta, once an ecologically rich and economically productive region, has undergone severe hydrological and ecological degradation due to the dramatic reduction of river flow over recent decades. This study presents field measurements and mathematical modelling results for three key reservoirs in the Muynak district of Karakalpakstan: the Mezhdurechye Reservoir, Muynak Bay and Rybachy Bay. Through GPS-assisted geodetic surveys conducted in 2022–2023, the actual morphometric parameters of each reservoir were determined and compared with GIS-based estimates. A hydrological water balance model was developed using differential equations and calibrated against observed flow data at the Samanbay gauging station for three representative years: a high-water year (2010), an average-water year (2019), and a low-water year (2001). The results indicate that, under current infrastructure conditions, the reservoirs can collectively store only 499.99 million m³ of water, with large volumes of potentially useful freshwater are discharged irreversibly to the dried bed of the Aral Sea. Following the reconstruction of hydraulic structures and canals, the combined storage capacity could reach 1,169.5 million m³, allowing an additional 669.51 million m³ to be retained in the delta. Hydrobiological surveys recorded 27 zooplankton species and 14–15 fish species, indicating substantially lower diversity compared with historical records as a consequence of deteriorating hydrological conditions. These findings provide a scientific basis for optimising the water-supply regime of the Amu Darya delta reservoirs and restoring the ecological and economic potential of the Southern Aral Sea region.
Hydrological and Hydrobiological Assessment of Reservoirs in the Amu Darya Delta: Towards an Improved Water-Supply Regime
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References
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