IDENTIFICATION AND ASSESSMENT OF NON-POINT SOURCE POLLUTION IN THE CHAIHE RESERVOIR CATCHMENT USING SWAT

Soil and water assessment tool(SWAT) was selected to simulate runoff,sediment and non-point source pollution in the Chaihe reservoir watershed.The main sources of non-point source pollution were analyzed and input method was discussed.After the runoff and sediment were validated,non-point source pollution in the watershed was modeled and evaluated.Data showed that SWAT model performed satisfactorily in the study area for simulated runoff,sediment and water quality.The trends matched well and peaks fluctuated between observed and simulated values.Spatial analysis revealed that non-point source pollution in the study area was spatially-distributed.TN and TP load was found to be concentrated in the middle and downstream parts of the watershed,critical areas with strong agricultural activities.Contribution rate analysis showed that fertilizer application and livestock were major contributors for TN and TP load,which should be the key factors for non-point source pollution.