Surface Water

The study assesses the quantum of seepage to the aquifers through percolation ponds and establishes their zone of influence, and based on these, correlates the quantum of seepage to the total storage loss in the pond. The assessment of the benefits of the ponds, in terms of artificial recharge to the aquifers is done through an intensive study of two percolation ponds in Tamil Nadu.

A percolation pond is a small water harvesting structure, constructed across a natural stream or water course to harvest and impound the runoff from the catchments for a longer time, to facilitate vertical and lateral percolation of impounded water into the soil substrata, thereby recharging groundwater storage in the zone of influence of the pond.

The study presents a preliminary hydrological investigation of the Deepar Beel, a natural freshwater lake near Guwahati, and notes the theoretical aspects of the techniques to be used, methodologies and instruments for conducting a detailed study of the natural processes at hand.

Deepar Beel acts as a natural stormwater reservoir during monsoon period and is greatly influenced by the rapid urbanization and improper land use pattern of Guwahati. It receives a large portion of sewage of the city, but the preliminary investigations reveal that the Beel is largely free from significant levels of pollution. This is due to the dilution effects of large storm water runoff during monsoons as also the release of the Beel water to river Brahmaputra through the Khanajun outlet. Yet, the soil quality is found to have deteriorated to a large extent.

Various parameters of soil and water quality indicate that the process of eutrophication is in progress in this wetland. Although many trace elements are present in the Beel sediments, no known toxic effects are observed on aquatic life. Increasing sedimentation and reduction in lake water capacity and inflow are also observed.

The study undertakes an exhaustive survey of the morphometric features of the Mansar lake, Udhampur district to prepare a bathymetric map of the lake. The map is useful in understanding the lake hydrological behavior through a study of volume, sedimentation rate and identification of the high siltation zone. The study is significant as the lake water can be utilized for drinking and irrigation purposes for the water scarce Kandi belt of Jammu.

The study prepares a landuse and landcover map of Devak catchment of Ujh river basin in Jammu for the years 1958, 1979, 1990 and 1998 using image processing and visual interpretation techniques. It involves analysis of IRS-1A L2B2 (FCC) data for the year 1990, IRS -1C LISS III (digital data) for the year 1998 and SoI topographic maps for the year 1958 and 1979.

The study suggests a procedure based on the methodology of Gustard et al (1992) for estimation of baseflow index (BFI) using the mean daily discharge data over a period of 4 to 6 years for three rivers between the Mahanadi and Godavari deltas. The rivers from the Zone 4 (A) are Rushikuliya at Purushottampur in Orissa, Nagavalli at Narayanpuram wier and Sarada at Anakapalli in Andhra Pradesh.

The study applies the methodology developed by United States Department of Agriculture’s (USDA), Soil Conservation Services (SCS) for the nine subwatersheds of the representative Dudhnai basin in Assam & Meghalaya and estimates the runoff volume on a daily basis for the period 1986-1991. The method is widely adopted for the estimation of runoff from rainfall depths and takes into account the important physical aspects of a basin on which runoff depends such as land-use, hydrological soil cover and antecedent moisture condition.

The study attempts to determine the adsorption characteristics of bed sediments of rivers for the control of metal pollution. In particular, it looks at adsorption of zinc ions on bed sediments for the river Ganga at Hardwar. In the natural conditions of river water, suspended loads and sediments have an important function of buffering higher metal concentrations of water, particularly by adsorption or precipitation. 

The study attempts to find out the pollution potential in the Hindon river, a polluted river in western Uttar Pradesh. Qualitative and quantitative estimation of pesticides was done using gas chromatography. Among various organic, inorganic and biological water pollutants, pesticides are very dangerous and harmful because of their carcinogenic properties. Pesticides are bio-accumulative and relatively stable and therefore require close monitoring.

The hydrological study develops a water balance of the Lake Nainital to facilitate the utilization of its water in a planned and systematic manner. The lack of knowledge of input and output parameters such as subsurface inflow, use of lake water for domestic and industrial purposes, evaporation loss and leakage from lake including the outflow through sluice gates had created uncertainty in determining the availability of water in the lake. The study attempts to understand the behavior of the input and output parameters in detail by using both conventional and isotopic techniques.

The lake meets the local drinking and domestic water needs and is for the most part fed by rainfall during monsoon and by inflow from perennial springs and subsurface inflow during the non-monsoon season.

The study attempts to do a field and laboratory determination of soil moisture characteristics such as particle size distribution, hydraulic conductivity and soil moisture retention curve in a part of the Hindon river catchment and studies the variation of these along the river in its upstream reach.