Surface Water

The report presents the analysis of surface runoff and baseflow carried out for the Ariyanayakipuram anicut, Tambarapani basin, Tamil Nadu for a period of 13 years (1983-95). The hydrological behavior of catchments is a very complex phenomenon and is controlled by a large number of climatic and physiographic factors that vary in time and space. The analysis shows that the contribution of baseflow at Ariyanayakipuram anicut was observed to be more.

The report on Suddagedda basin, a representative basin of the east flowing rivers of medium sized basins in the east coast of India, presents the outcomes of the infiltration tests carried out using Double Ring Infiltrometer. The basin soil is mainly grouped into three types viz clay loams to clay, sandy loams and forest & loamy skeletal. A total of twenty-eight infiltration tests have been conducted using double ring infiltrometers.

The report presents a hydrologic simulation model, HYSIM for modeling the daily flows of the Brahmani river at Rengali reservoir in Orissa. Considering the large catchment area of 25,250 sqkm at Rengali reservoir, for modeling purposes the basin has been divided into two sub-basins viz, Upper Sub-basin and Lower Sub-basin. The Upper Sub-basin having a catchment area of 16,900 sqkm up to Bolani gauging site is treated as a nominal sub-basin since the daily flows from this sub-basin as recorded at Bolani gauging site are available.

The report deals with hydrological soil classification in Sher-Umar river doab in Narmada basin. The study and classification of soil has in the past been undertaken by engineers and agriculturists who have confined themselves to those soil properties and materials in which they had a special interest. The soils have also been studied by geologists, but the geological description of an area does not include the information required by soil scientists. The classification designed by soil users have tended to be of limited value to others as they were designed to serve a specific and limited purpose.

In the study, the methodology developed at the National Institute of Hydrology to relate Clark model parameters to geomorphological characteristics has been used to develop unit hydrograph for two hard rock catchments, Barchi nala and Malaprabha up to Khanapur. This model has already been successfully implemented for simulation of flood events in small catchments of Upper Narmada and Kolar sub-basin of Narmada river as well as the Tapi sub-zone.

The report presents an estimation of soil erosion and sediment yield for the Karso catchment of Barakar basin in Jharkhand using ANSWERS model. Quantitative assessments of runoff and soil erosion are needed for proper management of land and water resources.

The present study aims to estimate the soil moisture movement and recharge to groundwater in Saharanpur due to monsoon rains through the unsaturated porous media in case of cultivated and uncultivated fields. Artificial radioisotope was injected at two uncultivated and five cultivated sites before the onset of monsoon and soil samples were collected from the injection points after the rainy season.

The report presents a hydrogeological and geochemical study of groundwater flow for the Suddagedda basin of Andhra Pradesh. Planning of water resources development projects calls for an understanding and analysis of the hydrological characteristics of the region. The hydrogeology and geochemistry of the basin needs to be investigated particularly for a groundwater resources development project.

A peer paper in Science Magazine focuses on the core of a riverine system, the upstream basin, and its impact on the entire river basin.

The report presents a seasonal rainfall-runoff model developed for the Saurashtra region as well as parts of Narmada river basin. The successful planning and implementation of water resources projects require reliable data on volumetric runoff. It is not feasible to have discharge stations in all the river basins of interest given resource constraints. Therefore, regional rainfall-runoff models are preferred. The utility of such models can be improved if rainfall-runoff models for different regions are developed using data specific to the regions.