Surface Water

The report is set in the context of the growing application of computers in the field of hydrology, and the consequent development of large number of softwares for hydrological and allied applications. The report is structured as a Directory and presents brief details about softwares for hydrological and general purpose application available with the National Institute of Hydrology.

The study undertakes hydrological land use mapping in Narmada basin from Jabalpur to Hoshangabad by using various methods right from empirical formulae to Soil Conservation Services Curve Number (SCS-CN) method for design discharge computations and continuous runoff modeling. The SCS Curve Number method is used to derive an empirical relationship of the catchment hydrological variables and based on this the dimensional unit hydrograph is prepared and continuous runoff modeling done.

The study uses GIS techniques for spatial discretization of the Karso catchment into time-area segments to be used in numerical solutions of the governing differential equations for rainfall-runoff-erosion process. Various thematic layers such as soil, land use, slope, flow direction and Digital Elevation Model (DEM) were generated for the catchment using various tools available in GIS. These thematic layers were further utilized to generate attribute information such as Manning’s n, USLE K and C parameters for use in the rainfall-runoff-soil erosion model.

The study, which is a part of the representative basin studies, attempts to do a morphometric analysis of the Suddagedda basin of Andhra Pradesh. The linear, areal and relief aspects pertaining to morphology are studied. In ungauged basins and basins with very little hydrological data, the study of geomorphologic characteristics is important as these can be related with the hydrological characteristics of the basin and thus provide a simple way to understand the hydrologic behavior of various basins.

The study uses Water Erosion Prediction Project (WEPP) model of the United States Department of Agriculture (USDA) to simulate the flow and erosion processes in Sallopat watershed of Mahi river basin in Banswara, Rajasthan. The WEPP model is a distributed, continuous, small agricultural watershed erosion model. It can simulate the effects of management practices and land use changes on the spatial and temporal variability of the erosion processes within a watershed system. The major features of this model are the ability to –

• Delineate areas of detachment and deposition on a hill slope or along a channel reach
• Account for the effects of management and land use changes on the erosion process
• Account for the effects of backwater on detachment, transport and deposition processes within channels

The study develops a regional hydrological model for estimating flow characteristics at ungauged sites of Narmada basin using climatological, hydrological and morphological variables. The term low flow is broadly used to describe stream flows that are significantly below average or below normal flow levels.

The study attempts water quality monitoring of Mansar lake to detect the various water quality parameters. The lake water conditions were monitored by collecting water samples from different depths to determine the spatial and temporal variations.

WASSAN (Watershed Support Services and Activities Network)

Location:         Hyderabad, Andhra Pradesh
Last Date:                15^th July 2010

The study deals with adsorption of lead and zinc ions on the bed sediments of river Kali in western Uttar Pradesh. Adsorption is one of the most important processes in water quality control, which influences the transport of pollutants in aquatic environment.

The study demonstrates Geographic Information Systems (GIS) based methodology for identification of sediment source areas and prediction of storm sediment yield for small watersheds. The Nagwa watershed in Bihar was discretized in to 50m grid cells using Integrated Land and Water Information Systems (ILWIS) GIS package, and unique drainage directions were obtained using GIS analysis. Also, a threshold channel network was generated from Digital Elevation Model (DEM) of the watershed. Actual observed drainage and generated drainage networks were superimposed and were found identical.