National Institute of Hydrology

The study deals with flow computation in Saptamukhi river estuary in Sunderbans delta of West Bengal using finite element method. Complex interactions between physical, chemical and biological processes are present in coastal areas. Water circulation is one of the most important factors controlling these processes. The study of the real hydrodynamic regime and proper management of estuaries, lagoons and coastal regions due to high tides, peak flows erosion, sedimentation and pollutant load discharges is vital.

The report presents flood plain mapping of Phulbari area within the flood plains of Brahmaputra basin in the States of Assam and Meghalaya using satellite data. Flood is a natural calamity in which most parts of the north-eastern region are ravaged. Management of the problem in these disastrous flood affected areas often requires flood plain mapping for protection and resource development. This has mostly being done in real time on the basis of time consuming and often hazardous ground based surveys.

The report deals with estimation of evaporation losses from water surface in Tawa reservoir in Hoshangabad district of Madhya Pradesh. The study is third in the series of evaporation studies to assess the adaptability of different methods for estimation of evaporation from free water surfaces in semi-arid areas. The estimates of evaporation from free water surface obtained by four methods namely Penman, Kohler, Van Bavel and Morton are compared with observed pan values on monthly, seasonal and annual basis.

The report deals with Geographical Information Systems (GIS) based rainfall-runoff modeling using Topography Model (TOPMODEL) for the Hemavathy catchment of Cauvery basin in Western Ghats of Karnataka. The TOPMODEL is a variable contribution area model in which the predominant factors determining the formation of runoff are represented by the topography of the basin and a negative exponential law linking the transmissivity of the soil with the vertical distance from the ground level.

The study deals with the analysis of surface and groundwater flow process in Dakshina Kannada district in Western Ghats of Karnataka. The area receives over 4000 mm rainfall annually but is still faced with acute shortage of freshwater during summer months. The study attempts to identify the surface and sub-surface flow process through geohydrological and geomorphological investigations in the Sithanadhi and Netravathi basins.

The report presents the hydrologic information and news available from print media and various government agencies mostly for the year 1999-2000 compiled problem-wise and basin-wise for the whole country.

The study attempted to estimate the actual crop evapotranspiration from minimum weather data of Tavanur, Kerala and resulted in an Artificial Neural Network (ANN) model, which makes use of average temperature data to estimate the actual evapotranspiration. The effectiveness of this model was evaluated using various statistical indices. The results of this model were compared with various existing techniques. The analysis led to the conclusion that the ANN models were performing better than all existing techniques for computing the actual evapotranspiration. However, the study was based on a single season lysimeter data and more research work may be required to reinforce this conclusion.

The study deals with identification of water quality monitoring sites on Kshipra river of Ujjain. The location of permanent sampling station is probably the most critical factor in a monitoring network which collects water quality data. If the samples collected are not representative of the water mass, the frequency of samplings as well as the mode of data interpretation and presentation become inconsequential.

The report presents the hydrologic soil classification of Dudhnai sub-basin based on regional information collected from various agencies supplemented by field and laboratory experiments on the soil samples collected from time to time. As required by various soil classification systems, soil properties together with other information have been studied and grouped into different classes as a reference base for future hydrological studies of the basin.

The report presents infiltration studies of the year 1996-97 for the Bargi Left Bank Canal Command area of Narsinghpur district of Madhya Pradesh. Infiltration studies are mainly addressed to a variety of applications for managing water resources. The design of methods for estimation of flood mitigation and erosion control is often based on estimates of peak discharge derived from prediction of infiltration rate. Water conservation procedures require computation of cumulative infiltration to produce estimates of runoff yield.