Comparison of Hydrology and Eco Hydrology Methods in Environmental Flow Estimation of Mahabad River

In water resources management and operation, especially for dam reservoirs, supplying the minimum water demand for protecting the life of the different plant and aquatic species is essential. Allocating the environmental flow for Mahabad River, as one of the most important rivers in the Urmia Lake basin, is very crucial. Therefore, the purpose of this study was to estimate the minimum environmental flow for Mahabad River using Eco-Hydrology methods.

In this study, the environmental flow for Mahabad River was estimated by five methods, namely Tenant, Tessman, Flow Duration Curve (FDC) Shifting, Desktop Reserve Model (DRM), and Flow Duration Curve Analysis (FDCA).

According to the results obtained in this study, to protect Mahabad River in the acceptable minimum environmental condition, the FDC shifting model considering class B (35.1% MAR (mean annual runoff), equivalent to 2.75 m³/s) and DRM considering class B/C (27.24% MAR, equal to 2.13 m³/s) led to approximately similar and acceptable results.

Generally, the FDC shifting model and DRM that consider different hydrological classes are preferable to other methods, and these methods can be used to determine the environmental flow for Mahabad River.