National Institute of Hydrology

The study looks at soil moisture movement and recharge to groundwater using nuclear methods like tritium tagging. It estimates the recharge to groundwater due to monsoon rain and irrigation through the unsaturated porous media in case of cultivated and uncultivated fields.

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.

The study carries out sediment yield estimation for the Shakkar catchment of the Narmada river in Madhya Pradesh and successfully implements a methodology for prioritization using Geographical Information Systems (GIS) and image processing on ERDAS and ILWIS software.

The study deals with the estimation of hydrological soil parameters of the doab between Sher, Umar river and Bargi left bank canal in Narsinghpur district of Madhya Pradesh. The soil properties determined are soil texture, soil moisture characteristic curves and saturated hydraulic conductivity.

The report presents the preliminary results of a hydrological study in Danda watershed, a small hilly watershed located in Tehri-Garhwal, representative of the mountainous sub-humid agro-ecological region in the western Himalayas.

In this study, a spatially distributed unit hydrograph was developed for the Kolar basin in Madhya Pradesh using Arc Info GIS package. The one-hour distributed hydrograph was determined for the basin using S hydrograph technique from the time-area diagram of the basin.

The report deals with the findings of a water quality study of Mansar lake in Udhampur district of Jammu and Kashmir. The water samples from different locations at the surface and from three zones (viz, epilimnion, metalimnion and hypolimnion) were collected and physico-analysis carried out.

The study attempts to do a space-time distribution of rainstorms associated with the tropical cyclones in the Bay of Bengal over a period of 20 years from 1976 to 1996.

The magnitude of peak flood and shape of the flood hydrograph depends not only on the magnitude of the total storm rainfall but also on its distribution in space and time. Improvements of the accuracy and timeliness of hydrological forecasting would thus largely depend on the prediction of rainfall distribution in space and time.

In this study, groundwater quality monitoring and evaluation of Greater Guwahati is presented based on the physico-chemical characteristics of thirty samples collected on grid pattern. The various parameters analyzed include pH, electrical conductivity, temperature, Dissolved Oxygen (DO), Total Dissolved Solids (TDS), alkalinity, hardness, Na⁺, K⁺, CA⁺⁺, Mg⁺⁺, NO₃^-, SO4^--, Cl^- and F^-. The results were compared with water quality standards prescribed by BIS and WHO.

In this study, NASMO model, a rainfall-runoff method, which uses the SCS method to determine effective rainfall, the linear reservoir method to route the runoff over land and the modified Puls method to route the runoff in the stream have been applied for hydrological modeling of the Malaprabha catchment in Karnataka. Geographical Information Systems (GIS) has been applied to derive the catchment characteristics like shape, size, slope and land use pattern.