Sediment Study in Western part of Himalayan Watershed Using Remote sensing and GIS

Abstract

The Present study was carried out to sediment study in western part of Himalayan watershed using remote sensing and GIS from Rampur to Kasol are considered in Himachal state with the objectives of (i). To estimate the runoff and sediment yield using Arc SWAT (Soil and Water Assessment tool). (ii) To validate the estimated runoff and sediment yield for the watershed. Application of Arc SWAT2005 in integration with Remote Sensing and GIS to estimate the runoff, sediment yield and other hydrological parameters of the area Rampur and Kasol an intermediate basin of Satluj river located in western Himalayan regions in India. The DEM was generated to prepare slope map. The Soil Map was prepared from NBSS&LUP soil map with a scale of 1: 500,000. About 60.45 percent of soil area falls under Fine-Loamy soil having Hydrological group-D and 17.94 percent of soil area falls under Course Loamy soil with hydrological Group-D. In the study area 26 sub watersheds are formed. The area delineated by the Arc SWAT interface was found to be 81761ha against the manually delineated area of 81790 ha. The error of calculation was found to be 0.01%. Rampur to Kasol an intermediate basin of Satluj river was used to estimate the runoff and sediment yields for the data of mainly eleven years from 1990 to 2000. The calibration period reported the value of R2 is 0.55 and 0.92 for daily and monthly results. The values of Nash-Sutcliffe R2NS for daily and monthly results were found to be 0.74 and 0.87 respectively. The model estimated results showed the correlation during sediment calibration having R2 value are 0.35 & 0.40 for daily and monthly basis respectively. The graphical validation analysis showed the R2 values is 0.65 for monthly runoff values for 1998 to 1999 with RNS values 0.46 and 0.66 for daily and monthly respectively. The validated R2 value was observed to be 0.50 for monthly sediment yield values for 1998 to 1999 respectively. There is reasonably good results between estimated and observed daily and monthly data for these years and for the current study basin from Rampur to Kasol. The total simulated sediment yield was observed to be 40.124, 25.35 & 48.664 (t/ha) as against the observed sediment yield of 133.245,145.850 & 140.565 (t/ha) respectively for the validated year 1998 to 2000.