National Institute of Hydrology

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 report gives a reviewed summary of various developments in the field of artificial recharge of groundwater at national and international levels. Different methods of recharging have been discussed in detail with reference to their design criteria, application and economic feasibility. The report also provides the details of field application.

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 report presents regional flood frequency curves developed by fitting L-moment based GEV distribution to annual maximum peak flood data of small to medium sized catchments of the seven hydrometeorological sub-zones of zone 3 and combined zone 3 of India. The effect of regional heterogeneity is studied by comparing the growth factors of various sub-zones and combined zone 3. The flood frequency curves based on probability weighted moment (PWM) approach have been compared with the flood frequency curves based on L moment approach.

The study on aquifer response modeling was undertaken for the southern channel command area of the Pennar delta canal system in Andhra Pradesh to understand the potential and dependability of groundwater supplies in the study area so that limited surface waters could be allocated to other uses or areas.

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.