Use of Holistic Environmental Flow Assessment for the Alijanchay River, Azerbaijan

Holistic environmental flow assessment includes evaluation of chemical, biological, hydrological, and morphological changes predicted from disrupting a river flow regime. Using available water chemistry together with biological and hydrological surveys, we report and assess environmental flows of the Alijanchay River, an important tributary of the Kura River, at four monitoring stations located in Azerbaijan. The river’s natural flow regime has changed significantly due to the irrigation activities in the middle and lower reaches and further development is planned through construction of new reservoirs. Our methodology is based on the results of morphological, hydrological, and hydrobiological observations and analysis of the physical and chemical parameters of the river. Environmental flow was evaluated by six hydrological methods proposed in the literature, and a comparative analysis shows that its value has increased from 13.6 to 27.1% of the annual flow volume, consistent with increased pressure on this important surface water supply. Water Quality Indices (WQI) further show seasonal changes of water quality in this important water supply, impacting sustainable uses for drinking and agriculture. Parameters most affected by seasonal changes are turbidity, suspended solids, and dissolved oxygen. Further degradation of environmental flows of this important watershed in Azerbaijan are likely from the planned development. A more comprehensive holistic ecological flow can help support a sustainable plan for use of Alijanchay River basin water reserves, and, if resources are provided for other basins, can support development elsewhere.