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Remote Sensing and GIS application studies at national institute of hydrology
Soil Erosion and sediment yield modelling using kinematic Wave in GIS Environment In this study GIS techniques have been utilised for spatial discretization of a catchment in to a time-area segments to be used in numerical solutions of the governing differential equations in rainfall-runoff-erosion process. Various thematic layers such as soil, land use, slope, flow direction, DEM were generated for the Karso catchment in Bihar using various tools available in GIS. These thematic layers were further utilised to generate attribute information such as Manning's "n", USLE "K" and "C" parameters for use in rainfall-runoff-soil erosion model. Based on DEM and related attribute information of the catchment, time-area map of the catchment was prepared and used for spatial discretization of the catchment.
Watershed Modelling With GIS Based Distributed Unit Hydrograph Approach In this study a spatially distributed unit hydrograph for Temur watershed at railway bridge no.293 (M. P.) has been developed. The method of distributed unit hydrograph computation allows for spatial non-uniformity of excess rainfall. Consequently, it is based on the time-area method derived using GIS. The GIS allows development of a watershed's channel network for calculation of realistic travel times, it handles the distributed excess rainfall in calculating local surface runoff rates as inputs for channel flow and it compiles the time-area diagram from which distributed unit hydrograph is derived.
Flood estimation using a GIUH based on a conceptual rainfall-runoff model and GIS Estimation of design flood for hydrological design of various water resources structures, particularly for medium and major water resources schemes, has been one of the most active areas of research for the hydrologists and water resources engineers. Geomorphological Instantaneous Unit Hydrographs (GIUH) have been proposed by several engineers as a tool to simulate runoff hydrographs from rainfall for ungauged catchments. The important geomorphological parameters which represent the linear, areal and slope aspects of the catchement are required to be evaluated either from toposheets or from other indirect means. Application of GIS package provides an efficient and accurate means for the evaluation of these characteristics.
GIS for estimation of direct runoff potential For the estimation of the amount of direct runoff that will be produced from a basin, various hydrologic models are available. Soil Conservation Services (SCS) model is most widely used for the estimation of direct runoff. All the factors of SCS model are geographic in character. Due to the geographic nature of these factors, SCS runoff model can easily be modelled into GIS. In this study, Kolar subbasin of Narmada has been chosen for carrying out runoff potential estimation using ILWIS. For the rainfall events of 12, 13 and 14th. August 1989, direct runoff was computed using SCS equation.
Reservoir sedimentation study for Ukai dam using satellite data In the present study, the sedimentation rate and volume was determined in the Ukai reservoir using the remote sensing data. Based on the annual maximum and minimum observed levels, the post-monsoon period of the year 1993-94 was chosen for analysis. Remote sensing data of IRS-1B satellite and LISS-II sensor was acquired for eight different dates and revised water spread area was extracted. The standard signature characteristics of different surface features (water, soil and vegetation) were utilised for separating water pixels from other surface features. The resulting imagery of water pixels was compared with the standard FCC and near-IR imagery.
General Remarks
In order to meet the growing demand for food, fuel and fodder of ever increasing population land and water resources need to be optimally utilised. It requires timely and reliable information on available land and water resources which could be derived from space borne multispectral data. GIS has evolved as a highly sophisticated data management system to put together and store the voluminous data typically required for hydrological studies. Thus remote sensing and GIS together provide information base for efficient management of water resources. The synoptic view provided by satellite remote sensing and the analysis capability provided by GIS offer a technologically appropriate method for studying these resources. The National Institute of Hydrology has carried out above mentioned studies and many other studies related with land use/land cover mapping, reservoir sedimentation, snow cover and snow melt modelling, soil erosion studies, rainfall runoff modelling in various parts of India. These studies have demonstrated capabilities of remote sensing and geographic information system in hydrological applications.
While application of remote sensing and GIS techniques in hydrology has made considerable progress, still more remains to be done to make these tools operationalised. Sustained efforts in consolidating results obtained so far and in developing operational methodology packages are needed. There is need to evolve a well co-ordinated programme in this area with focus on developing of standard methodologies and software as well as training and technology transfer. There is also need for wide spread availability of remote sensing and GIS outputs in digital mode for various applications in water sector. Remote sensing and geographic information system have to play a vital role in decision support system for various activities related with development and management of land and water resources in an environmentally sound and sustainable manner.
REFERENCE
- Kothyari, U.C., S.K.Jain,’ Sediment yield estimation using GIS’, Hydrological Sciences Journal , 46(2), December, 1997
- Jain, M.K. GIS based rainfall runoff modelling for Hemavathi catchment. CR/AR 22/96-97, National Institute of Hydrology, Roorkee.
- Jain, M.K. Watershed modelling with GIS based distributed unit hydrograph approach. CS/AR 8/97-98, National Institute of Hydrology, Roorkee.
- Jain S.K., Hemant Chowdhary, S.M.Seth, R.K.Nema,’ Flood estimation using a GIUH based on a conceptual rainfall-runoff model and a GIS, ITC Journal 1997-1.
- Jain S.K., G.W.Kite, Naresh Kumar, T.Ahmad,’SLURP Model and GIS for estimation of runoff in a part of Satluj catchment, India’, Hydrological Sciences Journal, 43(6), December, 1998.
- Jain S.K., K.K.Dash, Ranvir Singh,’GIS for estimation of direct runoff potential’, Journal of Indian Water Resources Society, Vol.2, No.1 ,January, 1996
- Jain, S.K.,' Integration of GIS and Remote Sensing in soil erosion studies CS(AR) 186, 1995-96
- Jain, S.K.,' Soil erosion assessment using Remote sensing and GIS technique, CS(AR) 204, 1995-96
- Rathore D.S. and S.K.Jain,' Land capability classification in a part of Narmda basin, CS(AR) 178, 1994-95
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