Low flow analysis in Porsuk Creek Basin

Identifying low flow characteristics in a basin can support meeting water demand by without endangering aquatic ecosystems and by considering water potential of the basin during dry periods. Low‐ flow analysis is a significant tool that provides information about the period and magnitude of water shortage. This study aims to identify long‐term variability of low flows in terms of threshold value, duration and seasonality by analyzing daily streamflow data of 4 gauging stations in Porsuk Creek Basin for the period 1969‐2011. Descriptive statistics were employed together with flow duration curve (for Q90 threshold) and Streamflow Deficit Index (SDI) analysis. Threshold values differ between upper and lower parts of the Porsuk Creek basin. Temporal analysis indicated that threshold values tend to decrease and in addition to this low flow periods are starting earlier. These results are not only related with decreasing of precipitation amount and changing in precipitation type but also connected with water use in the basin.