Programme OS3d Climate change: Planning,
adaptation and mitigation abstract 823
Understanding hydrologic variability for better surface water allocations in
Karkheh Basin Iran
Author(s): Ilyas Masih, Hugh Turral, Ahmad Mobin-ud-Din, Stefan Uhlenbrook
Ilyas Masih, Hugh Turral and Mobin-ud-Din Ahamd
are Research Officer, Senior Researcher and Principal Researcher/Theme Leader, respectively, at International
Water Management Institute (IWMI), Global Research Division, P. O. Box. 2075, Colombo, Sri Lanka.
Keyword(s): surface water, variability, flow duration
analysis, water allocation, Karkheh basin
Article:
Poster:
Session: OS3d Climate change: Planning,
adaptation and mitigation
Abstract Water-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.