Assessment the estimation of suspended load under the influence of land use change using SWAT model (Case study: Yalfan watershed)

In a watershed, land use As one of the most effective factors in basin hydrologic response, Can have significant role in the hydrological cycle and water resources. The knowledge of the effects of land use change on basin hydrology responses can help to determine the appropriate strategy to achieve sustainable development of water resources and a management model. The purpose of this study is to evaluate the hydrological effect of land use changes over the last 25 years in the Yalfan watershed. Swat model (2009) was used to simulate suspended load. Meteorological data, digital land use map and soil and digital elevation model of the research area was prepared. After calibration (2002 to 2007) and verification (2008 to 2010), In order to assess the impact of land use on suspended load, the 1989 and 2013 land use maps were created and introduced to the model. The result shows significant effects of land use change on suspended load. The changes in land use from 1989 to 2013 result in, increase of sediment load and runoff around 11 and 17 percent respectively and reduce ground water level about 16 percent. NS، R2، P-factor and R-factor were evaluated for calibration 0.54, 0.6, 0.48 , 2.3 , and 0.57, 0.65, 0.42 , 3.2 for verification respectively, approved that the model has a good ability to simulate sediment .