IWRA Proceedings

AbstractWater-limited environments occupy about half of the global land area and are highly sensitive to change due to scarcity and variable distribution of water and nutrients. Karkheh basin in Iran, a water limited region, exhibits increasing competition for scarce water resources between irrigation, domestic, hydropower and environment. Increasing demands for water are making sustainable water management more and more difficult particularly because of lack of understanding of basin hydrology and impacts of water resource development on different users across the basin. An in-depth study was conducted to examine the long-term variability of surface water resource by flow duration analysis using daily stream flow data from 1961 to 2001 at seven key locations across Karkheh basin. The mean monthly stream flows range from 3 to 98 m3/sec, 4 to 65 m3/sec, 10 to 222 m3/sec, 15 to 123 m3/sec, 40 to 385 m3/sec, 51 to 430 m3/sec and 38 to 398 m3/sec at key locations, namely Pole Chahr at Gamasiab , Ghore Bagestan at Gharesu, Holilan at Saymareh, Pole Dokhtar at Kashkan, Jelogir, Paye Pole and Hamedia stations at Karkheh rivers, respectively. The flow duration analysis reveals that water allocation planning on the basis of mean annual surface water availability could only provide a supply security in the range of 35-50 percent. The results clearly suggest that improving understanding of the hydrological variability of surface water resources and incorporating it into water development and allocation strategies is necessary for dealing with the competing water demands from irrigation, environment and other sectors of water use.