Toolkit for Evaluating Sustainability of Watersheds in Rainfed Regions

Abstract

Rainfed agro-ecological regions (AER) which encompass the semi-arid tropics (SAT) and hot dry and moist sub-humid regions of India, extends over 76.74 m ha out of the total geog. area of 90.4 m ha in the states of Andhra Pradesh (AP), Maharashtra (MAHA), Karnataka (KAR) and Tamilnadu (TN) in Peninsular India. In India as a whole, arid AER account for 33.98 m ha (10.36 %) while semi-arid AER cover 95.09 m ha (28.98%) with a transitional belt of 3.19 m ha or 1 % of the land area. Thus, rainfed AER is important for the country as a whole and watershed-based development has been accepted as an important component in the schemes for economic planning for development in this region. The rainfed AER encompassing Peninsular India receives an average annual rainfall of 500 mm (300-800 mm), which occur in 52 - 55 rainy days. Over 50 per cent of this rainfall occurs by way of thunderstorm that lasts for a few hours. Considering such a rainfall pattern, it is essential to harvest, store and use rainwater for undertaking agriculture and other allied activities for the rest of the year. Intensive rainfall events induce severe soil erosion in bare or sparsely vegetated land that is common in the region. Watershed Development and Management Program was initiated during 1980s to address these limitations of the rainfed AER (Planning Commission, 2001). Soil and Water Conservation Structures (S&WC) viz., check-dam, stone weirs, contour bund, live bunds, vegetative cover, key-line plantation, grass way etc. were planned to provide impediments to overland - runoff which induce soil erosion and depletion of nutrients from agricultural fields. Structures were laid to guide runoff to designated farm ponds and tanks for water harvesting on the surface, besides impounding water for facilitating deep percolation for groundwater recharge. Thus, Watershed Development Program (WDP) was considered the most comprehensive program for achieving agricultural and ecological sustainability in the rainfed regions in India. A hallmark of WDP 31 was the implementation of improved land management practices (LMP) for each aspect of agriculture and rural life in the rainfed regions. As India envisages sustaining an agricultural growth rate of 4.0 to 4.5 per cent in order to reduce food insecurity and poverty, while increasing rural purchasing power, it is essential to strive for achieving sustainable development through watershed development.