IMPROVING WATER RESOURCES MANAGEMENT IN ARID AND SEMI-ARID AREAS USING DISTRIBUTED HYDROLOGICAL MODELS AND SATELLITE-BASED DATA

Arid and semi-arid areas are usually characterized by strong climatic contrasts and rivers suffering seasonal drought and occasional precipitation. Distributed Hydrological Models (DHM) have, in principle, the advantage of spatially reflecting hydrological responses of basin, which is important for the Integrated Water Resources Management (IWRM). However, almost all distributed hydrological models have been primarily developed for humid areas. Arid and semi-arid areas have particular challenges that have received little attention. Based on this consideration, the purpose of this paper is to introduce a methodological study to deal with the main challenges of DHM application in arid and semi-arid areas. In order to deal with data scarcity, a new method for Prediction in Ungauged Basins (PUB) is developed to use globally covered data sets that are publicly available. The quality of these data sets, especially satellite-based precipitation data, is evaluated. A parsimonious version of BTOPMC (Block-wise use of TOPMODEL) is developed and blindly applied to the upstream of the Karaj Dam (basin area of 850 km2) in Iran and also upstream of the Kajaki Dam in the Helmand (Hirmand) river basin with an area of 48700 km2 in Afghanistan. The upstream of Karaj Dam has been used as a proxy-basin for the upstream of the Kajaki Dam to estimate necessary model parameters. Using satellitebased snow cover data, snow water equivalents of two basins are estimated. Moreover, during the same period, daily runoff is simulated using global coverage data sets as input data. The amount as well as inter-annual variations of inflow to dams simulated by the model are compared with scattered available observed data and show a good compatibility. The overall performance of the adopted method and developed model are encouraging for long-term modeling in ungauged basins using satellite-based precipitation data.

کلیدواژه ها:

Arid and semi-arid areas ، Distributed Hydrological Model ، IWRM ، Satellite-based precipitation ، Ungauged basins