Groundwater Recharge

This presentation by ACWADAM deals with monitoring of water quality in a watershed. It describes the process of going about conducting a hydrogeological study of the watershed, right from the study of the basic geology to the importance of the quality of groundwater in the watershed. The main hydrogeological provinces of India are described - (a) Hard rock regimes: Crystalline rocks, Volcanic (Deccan basalt), (b) Alluvial regimes, and (c) Consolidated sedimentary regimes: Soft sedimentary, Hard sedimentary.

This presentation by ACWADAM on aquifers states that a systematic approach to groundwater studies is required to understand how water exists in each type of rock or sediment for which hydrogeological mapping of aquifers becomes significant in every watershed programme. The necessity of studying the scientific aspects of groundwater such as its properties and distribution below the earth’s surface is highlighted.

This presentation by ACWADAM deals with groundwater modeling using the Water Evaluation and Planning System (WEAP) model. WEAP is a microcomputer tool for integrated water resources planning and operates on the basic principle of a water balance. WEAP is distinguished by its integrated approach to simulating water systems and by its policy orientation. It provides a comprehensive, flexible and user-friendly framework for policy analysis.

This presentation by ACWADAM on earth sciences in watershed management shows how the occurrence of water within a watershed is governed by the rock types occurring both at the surface and within the subsurface, their sequence and their structure. The presentation deals with the basic components involved in the mapping of a watershed –

• The type of rocks (lithology), and
• The structure (whether these are folded, faulted, fractured, jointed etc.,)

This presentation by ACWADAM deals with the importance of groundwater. It is well-known fact that groundwater forms a very crucial source of water supply in the national scenario on water resources today. And yet, it continues to remain a resource that is both abused and misused. Often, watershed projects suffer from insufficient inputs, especially hydrogeological to address the problem(s) of groundwater within the watersheds.

This presentation by ACWADAM deals with groundwater typologies in India. The typology of groundwater can be defined in many ways based on a) Uses of Groundwater, b) Geography, c) Geology, d) Hydrogeology (Aquifers), e) Groundwater Quality, f) Stage of Groundwater Development, and g) Socio-ecology of Groundwater.

This presentation by ACWADAM deals with the chemistry of groundwater. It is now recognized that the quality of groundwater is as important as its quantity. All groundwater contains salts in solution which are derived from the location and the movement of water through rocks. The quality of groundwater supply depends where and for what it is planned to be used. Thus water quality standards for drinking water, industrial water and irrigation water differ significantly.

This presentation by ACWADAM deals with the subject of groundwater balance. It begins by describing the skeleton for the water balance equation viz., ground surface, soil, aquifer and bed rock. It describes the processes subsequent to rainfall such as interception, initial detention, depression storage, infiltration, runoff, streamflow, soil moisture retention and recharge.

The watershed water balance equation is explained in terms of input (rainfall and water transfers) and output (runoff, evapotranspiration and infiltration). It notes that the input to a generalized water balance is rainfall whereas the input to a groundwater balance is infiltration. The difference between infiltration & recharge, natural & artificial recharge and interflow & discharge are explained thereafter. The water balance for an aquifer may vary, depending upon the nature of groundwater system –

• Watershed with a deep aquifer
• Watershed has both shallow and deep aquifers
• Watershed has only shallow aquifer

This presentation by ACWADAM deals with geological mapping. The occurrence of water within a watershed is governed by the rock types occurring both at the surface and within the subsurface, their sequence and their structure. The physical structure which plays host to the water within the watershed is geological. Every watershed programme must therefore include a fundamental understanding of this framework so that the development and management measures planned through such programmes are meaningful and properly justified technically.