SR-2 : Drought estimation and control

Abstract

Droughts form one extreme end of the hydrologic cycle, while floods are at the other end. Drought is a frequent hazard in India, striking in some part or the other. The most striking effect of droughts is that they cause local as well as regional imbalances and retard the economy of the nation. In spite of technological advancements made in this direction, still it continues to be a major factor of uncertainty.

The definition of term drought varies widely with area of interest and the kind of user. An extensive review of the available literature on drought has been made. The intensity of drought classification based on the parameters like climatological, parameters, soil moisture, evapotranspiration, plant factors, low stream flow levels or ground water levels etc. has been discussed. The commonly used drought indices have been also reviewed. Drought studies by water budget method, Palmer drought indices and associated two layer approach have been discussed in detail. The various mathematical, statistical and stochastic approaches to investigate the incidence, trend and prediction of drought have been dealt with.

An attempt has been made to review the impacts of droughts on various aspects e.g. agricultural production, morphology, land regime, reduction of water level in different water bodies, water quality, socio-economic-conditions etc.

The strategies for minimising the impacts of droughts both long and short term have been reviewed with special emphasis on development conservation, and utilisation of water resources adapting integrated land and water management approaches on watershed basis. Means of artificial recharging of groundwater have been also discussed.

It appears to be that there is no general agreement on definitions and methods of describing the drought phenomenon. On the basis of review made, the present state-of-knowledge on drought; existing technological gaps and future research needs have been briefly mentioned in the report.