Estimating Groundwater Recharge, Evapotranspiration and Surface Runoff using Land-use data: A Case Study in Northeast Iran

چکیده مقاله

Estimation of temporal and spatial distribution of recharge is a key factor for a long-term water resource planning, especially in semi-arid regions. The main objective of this is to assess the groundwater recharge, surface runoff and evapotranspiration in the Mashhad basin using a spatially distributed water balance model (WetSpass-M) in different land-use types. Distributed land-use map, groundwater depth, monthly climatological data (e.g. precipitation, temperature…..), monthly LAI, slope and soil texture maps are the basic relevant input data for the model. All inputs were prepared in the form of digital maps using GIS and remote sensing tools. Results of the model indicate that the long-term temporal and spatial average monthly rainfall of 22 mm was distributed as 14% of surface runoff, 29 % groundwater recharge and 57% of evapotranspiration. Resulting to the high evapotranspiration rate, high surface runoff and temperature, agricultural regions (including rain-fed and irrigation farming) has the lowest groundwater recharge. Analysis of the simulated results indicate that WetSpass-M model is good enough to simulate the components of water balance for the Mashhad basin.