文摘
Adequate evaluation of blue water fluxes in arid and semiarid areas is crucial for operational purposes such as evaluation of rain-fed agriculture, grazing potentials and for designing and construction of water dams. Evapotranspiration, runoff and deep recharge in such catchments are poorly understood due to the lack of meteorological and/or hydrological measurements. Modeling using proper parameterizations would probably be a viable alternative to gauge such resources. The present paper examines the water budget in a typical medium size semiarid watershed located in the mountainous areas in Jordan using a transient model. The watershed was discretized into 1 km side length, and the model was run for six continuous years using a daily time step. Many parameterizations used in the model were based on field measurements carried out in this particular environment where measurements of many hydro-meteorological parameters are scarce. Comparison between simulated results and long-term flow observations show that the model performs adequately. Results indicate that evapotranspiration, surface runoff, and deep recharge constitute around 87.5, 7.5 and 5 % of areal precipitation, respectively. Significant runoff occurs over steep terrains where vegetation cover is limited or devoid, implying the production of large quantities of sediments, which would adversely affect water quality and the life span of dams constructed over these catchments. Keywords Eastern Mediterranean Semiarid environments Climate gradient Blue water fluxes Climate change Spatial modeling