Groundwater

The report attempts asymptomatic estimation of runoff curve number for small hard rock watersheds from rainfall-runoff data.One of the major activities in Applied Hydrology is the estimation of storm event runoff from ungauged small watersheds. Such estimates are often required in the design of small hydraulic structures and in formulation of watershed management strategies.

The study focuses attention on the use of inverse modeling technique for estimation of rainfall-recharge in a coastal aquifer. MODINV (Modular Inverse Model), which is software for parameter optimization of 3-D groundwater flow model, MODFLOW is applied to the Central Godavari delta in Andhra Pradesh to estimate the distributed rainfall-recharge during monsoon season.

The report deals with the transportation behavior of lindane, a pesticide used commonly in the agricultural and public health sectors in India, through sandy and loamy soils. The contamination of groundwater by pesticides is a worldwide problem because of their tissue degradation and carcinogenic nature. They are bio-accumulative and relatively stable and therefore, require close monitoring.

The pesticides used for agricultural, forestry and domestic activities leach into the groundwater and therefore, it is very important to study their transportation behavior in different types of soil media.

This document by ACWADAM is a report of a rapid geohydrological assessment of some of the microwatersheds from parts of Bolangir district Orissa.

Bolangir district in Orissa forms a part of one of the hottest and backward regions of India with low land-productivity, and opportunities and technologies for agriculture in the district remain relatively unexplored.

Vagaries of rainfall and the underlying hard-rock geology further compound the problem and limit agricultural productivity to a great extent. Given such natural uncertainties, systematic implementation of a watershed management programme is the most viable avenue to overcome the problems of this region.

Bolangir district was thus selected as pilot area to conduct a pre-feasibility exercise for planning of water resources management. ACWADAM, Pune was invited, along with Samaj Pragati Sahayog, Bagli to conduct this pre-feasibility exercise.

The report attempts to provide solutions to the twin problems of waterlogging and salinity in the irrigated command area through various drainage or traditional reclamation measures viz controlling the intensity of irrigation, providing drainage system, lining, improving natural drainage, preventing seepage or adopting modern technology for application of water.

The report presents guidelines for hydrological investigations in a small watershed. A watershed is an individual entity, and is a naturally occurring unit of the landscape, which contains a complex array of interlinked and interdependent resources and activities irrespective of political boundaries. In addition, it is logical unit having readily identifiable boundaries and characteristics of water movement, which helps in coordinated planning and management.

The subsurface aquifer systems in Mahanadi delta region in Orissa (India) is largely characterized by two groups of freshwater aquifer systems, both of which are prone to saline water mixing/migration with time and development:

• The south western Mahanadi delta region is represented by unconfined to semi-confined freshwater aquifers underlained by brackish/saline aquifer systems with a diffusion boundary.
• The north eastern parts of Mahanadi delta is represented by deep freshwater confined aquifers overlained by brackish/saline water aquifers with aquitard/ aquiclude boundary.

The study provides an analysis of groundwater quality to identify probable pollution or contamination in coastal aquifers of Kakinada in Andhra Pradesh. Sampling surveys have been conducted in the months of May 99, August 99 and November 99 and about 186 water samples were collected from shallow wells, filter points, canal water and rainwater. The spatial and temporal variations of water quality parameters are presented in the report. 

In the present report a mathematical model has been developed for the study of stream aquifer interaction in multilayered system viz. a three-aquifer system, in which aquifers are separated by aquitards, considering varying stream-stage and vertical flow through aquitards. The model enables the computation of rates of recharge to the upper aquifer and exchanges of flow among aquifers along with the spatial and temporal distributions of piezometric heads in the aquifers.

The present study is in continuance with the earlier investigations made regarding the seepage from a surface water body in a multilayered aquifer system, wherein the influence of varying dimensions of a fractured-zone in a aquitard on the seepage from a source had been investigated. The objective is to examine the influence of a fractured-zone in a confining aquitard on the seepage from a surface water body. The issues covered include the influence of –

• The location with respect to the source of a fracture in the aquitard
• The position of the fractured aquitard at various depths in the aquifer system on the seepage from the source