Environmental flow assessment for downstream of Koyunbaba Dam

Nowadays, determination of minimum water flow from dams that are build on rivers, has a vital importance in order to utilize water resources effectively and effiviently. In this study, minimum water flow at Koyunbaba Dam is calculated based on two different hydrologic methods, namely flow duration curve and Tennant (1976) methods and they are compared with each other. During the study, In Tennant method, dry and wet periods are defined in two different ways. As a result of current study, based on Tennant method, for raid periods minimum 0,17 m3/sec and 0,09 m3/sec, for wet periods minimum 0,21 m3/sec ve 0,38 m3/sec water flow are calculated. Based on flow duration method Q70 and Q95 are calculated respectively 0,24 m3/sec and 0,06 m3/sec. Environmental flow amount calculated by Tennant – II method is higher than the long-term monthly minimum current value. Therefore, Tennant – II method is more appropriate than other selected methods.