This chapter presents the application of different hydrological models, remote sensing and Geographic Information System (GIS) in estimating runoff and soil loss from the Shivalik foothills. Soil and Water Assessment Tool (SWAT) is a river basin model being used since 1993 mainly by hydrologists for watershed hydrology related issues Soil erosion modeling is able to consider many of the complex interactions that influence rates of erosion by simulating erosion processes in the watershed. The integrated use of remote sensing and GIS could help to assess quantitative soil loss at various scales and also to identify areas that are at potential risk of soil erosion. The digital elevation model of the watershed, the soil and land use data and the climatic data of the area are required input to the model. SWAT is a physically based hydrologic model which requires physically based data.