National Institute of Hydrology

The study seeks to understand the problem of rainfall, particularly for identification of any trend or persistence in the rainfall series in the five districts of Sagar division of Madhya Pradesh. A statistical analysis of the rainfall pattern is conducted using World Meteorological Organization (WMO) recommended statistical techniques for climatological analysis. Besides studying the statistical parameters and cross correlation, other techniques like linear regression and polynomial regression have been applied to identify the presence of any trend. 

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.

The study attempts to develop a computerized model for Geomorphological Instantaneous Unit Hydrograph (GIUH) for estimation of flood hydrographs resulting from intermittent storms of varying intensity. The model applied to the rainfall-runoff data of the Myntdu-Leska basin of Meghalaya infers that the channel network and geomorphological features are closely related to the retention and discharge characteristics of the basin.

The theory of GIUH assumes that rainfall that occurs over a basin is assumed to be composed of infinite number of non-interacting drops of uniform size. After spending some time in one state in the channel or overland region, the drop makes transitions to another state to reach the basin outlet. Assuming one parameter, exponential time distribution of one drop chosen at random from the basin defines the IUH of the basin.

The study gives a systematic methodology to determine field hydraulic conductivity using Guelph Permeameter (GP), its limitation based on the experiences gained in the field and a comparison of its results with that estimated from the predictive method for the soils in Central Bihar. Predictive methods applying empirical formulae are used to ascertain hydraulic conductivity from easily determined factors like bulk density, porosity and water content.

Physically based hydrological models, soil water balance, groundwater flow and transport models require values of saturated and unsaturated hydraulic conductivity to solve the sub-surface flow and transport equations. Several field, laboratory and predictive methods are available for determination of this parameter. However, these methods have some advantages and some limitations. GP is used as a tool to determine the field hydraulic conductivity even when the water table is low. It is portable, durable and allows rapid field calculation of saturated and unsaturated hydraulic conductivity.

The study estimates the average soil loss using the Geographic Information Systems (GIS) tool of Integrated Land and Water Information Systems (ILWIS) and the Universal Soil Loss Equation (USLE) methodology for the Hire nadi catchment, in Yelbarga taluk, Koppal district of Karnataka, under different conditions.  

Scientific planning for soil conservation and water management requires knowledge of the relations among factors that cause and prevent soil and water loss.  Controlled studies on field plots and small watersheds have supplied vital information regarding these complex factors and their interrelations.

The report presents the status of urban hydrology and highlights some of the hydrological problems related to urbanization in the world and in India. It covers a discussion on urban hydrologic cycle, hydrological and related problems of India, impact of urbanization on streamflow and urban water management. Some information on available urban hydrological models and the recommendations for the management of urban areas is also included.

The problems of urban hydrology have been of world concern for several years, but there have been few compilations of background information and even fewer comprehensive investigations of specific urban situations. The new information and data are of vital importance to the development of urban hydrology research in future.

This report is a compilation of the hydrological news in the print media in the country for the year 2000. The report is an attempt to put forth diverse hydrologic information and events reflecting the problems and indicate solutions for hydrologists, planners and water resource managers in particular. National newspapers like Hindustan Times, Indian Express and Hindu have been referred to, for tracking the Indian hydrological events due to flood, drought, quality, demand supply and availability.

The report details out the status of landfill and waste disposal technologies in India & abroad and reviews the scientific studies undertaken to support its design for long-lasting performance. Hydrological considerations play a major role in the selection of landfill sites and in the design and performance of landfills for hazardous waste management. A landfill is a form of a biochemical reactor where the municipal solid waste (MSW) comes into contact with moisture, a catalyst, and gets decomposed into solid waste, gases and liquid contaminants (leachate) resulting in the release of heat. The design of the control and recovery systems requires the estimation of amount and composition of gas and leachate accurately, as also the changes in these with time. Lysimeters are used to simulate the landfill performance.

The report presents a review of several aspects of non-point source of pollution, like extent and effects of pollution in surface and groundwater bodies, pollution control, monitoring, modeling and management options. Non-point source pollution originates from diffuse land areas that contribute pollutants to surface and groundwater bodies. Sediments, nutrients and pesticides are transported from croplands either in a dissolved form in runoff or through adsorption onto eroded soil particles. Apart from this it can also enter groundwater through leaching.  

The report presents a literature review on the status of research related to saltwater intrusion and groundwater management in coastal and deltaic environments in the east coast of South India. The area is typically characterized by highly productive and alluvial aquifers and high use of both surface as well as groundwater. Seawater intrusion into the freshwater aquifers is extensive due to increased pumpages.

A quantitative understanding of the patterns of movement and mixing between freshwater and saline water and the factors that influence these processes is stressed in the report. It presents the mechanics of saltwater intrusion through studies by Ghyben and Herzberg and later on by Hubbert. A comprehensive review of studies by Reilly and Goodman relating to saltwater intrusion is discussed. Later advances in understanding saltwater-freshwater relationship through numerical models like sharp interface model and miscible flow model are described.