TR-20 : Identification of hydroenvironmental indices

Abstract

Water resources development projects represent an integral part of the entire complex of development aimed at the remarking of nature useful for man. These projects may be taken up for a variety of purposes including supply of drinking water, irrigation of crops, extraction of energy, transportation of goods and carrying away the wastes. While these water resources projects provide for various useful purposes, they may have indirect or inadvertent effects which are undesirable. These undesirable effects may be reflected in the physical, chemical, biological, social and economic components of the total environmental system. Such effects can be minimised if not eliminated, if certain indices to be referred to as hydro environmental, to characterise various components of environment likely to be affected, can be defined during the planning and decision making stages of these projects.

The present report classifies various types of water resources development projects, their impacts on environmental components, and identifies possible hydro environmental indices which would characterise the environmental system. Generally an environmental assessment must address all the quantitative and qualitative changes which would result from a water project and to these identified changes some values must be assigned. These values must be somehow balanced or weighted in relationship to the overall goals of a society and must also be described in simple and understandable terminology. Therefore, the need to develop such characteristic indices which may provide comparative information to aid in the evaluation and selection of a water project to meet a particular water related need, is greatly felt.

These indices once developed can be used for evaluation of water projects for environmental impact assessment studies. Proper evaluation of the various impacts would lead to having assessment of the net gain of the projects on public welfare. Identification of such indices is of greater importance for developing countries like ours and needs to be introduced in the planning process of future water resources development projects.