Determination of the Environmental Water Requirement Based on the Integrating Hydrology and Ecological Response

Lakes, vital for human survival, are highly productive ecosystems providing services such as water supply and nutrient regulation. However, escalating water scarcity, fueled by global population growth and climate change, necessitates a comprehensive, long-term approach. The research method used in the study is an integrated framework of hydrology and ecological response components to determine environmental water requirements for Ovan Lake, Iran. The research delves into Ovan Lake's hydrological components, exploring precipitation, evaporation, surface water, and groundwater exchange. Identifying the great reed warbler breeding operation on the lake's margin reed lands as a key ecological relationship, the study highlights its role in reflecting the favorable status of other species and providing conservation benefits. Maintaining a water depth between 50 and 70 cm near the reeds, along with a reed cover width of approximately 20 m in March, as the breeding month, is recommended to ensure optimal breeding conditions for great reed warbler. Correlations between hydrological conditions (water depth, area, and volume) and ecological water depth are established, estimating environmental water requirements at 241 and 207 thousand m3 during drought and wet periods, respectively. The analysis computes water shortfalls needed to meet environmental water needs under different scenarios and ecological conditions. It matches minimum and optimum water levels to drought and wet periods based on available conditions. Results indicate challenges in maintaining ecological conditions in late spring and summer due to reduced rainfall and increased evaporation, emphasizing the need for proactive management strategies to sustain Ovan Lake's environmental health and restoration.