Flow characterization of RamGanga River Catchment through hydrologic models

Abstract

The changes to river basin processes are a major cause of ecosystem degradation. How and where these processes have been altered by human activities over the past years, how and where they will change in future, could be described by river basin characterization. Thus river basin characterization is a way to model the relative changes to key basin processes. Complete characterization of a river basin calls for morphometric characterization of the watersheds located in the basin. Morphometry has been defined as quantitative measurements of landscape shape (Keller and Pinter, 1996). Remote sensing and GIS techniques for the morphometric analysis of watershed enable us to get better characterization of watersheds. newlineFor any type of hydrological event identification of trends in long term rainfall, runoff and sediment yields are important themes. Trends in stream flow may be changed due to anthropogenic influences in the catchment. Study of stream flow trends help us to get an idea about the changes in the river basin. newlineSoil and water are essential for the production of food for man and indeed for all forms of life (Gyssels et al., 2005). Soil erosion by water causes the loss of surface soil due to rain and runoff water and the intensity of it can be predicted by the modeling of soil loss (Kefi et al., 2011). For sediment yield modeling we require stream flow data which include direct as well as base flow but the sediments are contained only in direct flow. The direct flow could be determined by separating base flow from total flow. Base flow is defined as the portion of (stream) flow that comes from groundwater or other delayed sources (Tallaksen, 1995). Base flow estimation for a small catchment could be done by graphical methods with fewer amounts of data. Large catchments have large time of concentration which results in more error in base flow estimation by hydrograph method.