This case study deals with resolving the conflict over rural groundwater use between drinking water and irrigation supply in Tamil Nadu. In rural water-supply provision, resource availability has not received the attention it deserves. Illusions of abundance have clouded the reality that renewable freshwater is an increasingly scarce commodity, especially in more arid and densely-populated areas.
Some 73 per cent of Tamil Nadu State is underlain by a low-storage variably-weathered crystalline basement aquifer, which is heavily exploited for dry-season irrigated agriculture and the predominant source of rural domestic water supply. In recent years it has also been seriously impacted by drought, making rural groundwater supply provision both more-and-more costly and less-and-less reliable, with new water wells commonly drilled to depths of 100-150 m and sometimes encountering unacceptable quality.
A key question is to what extent can carefully-deployed, low-cost, recharge structures be used to enhance groundwater resources and rejuvenate drinking water wells preferentially and thus provide at least a medium-term solution to the problem. But no matter how merit-worthy, such structures will generally not be sufficient alone to halt the current trend of aquifer depletion without concomitant action on irrigation demand management.
This profile summarizes the socially responsive and technically-pragmatic approach developed by the Tamil Nadu Water & Drainage Board (TWADB) and GW MATE to this issue, in preparation for the Tamil Nadu Rural Water Supply & Sanitation Program - Groundwater Recharge & Resource Component (valued at US$ 68 million over 6 years).
A major water-supply program rooted at the territorial level of districts and villages (panchayats) represents an excellent opportunity to pilot local groundwater management initiatives and mobilize the local community on finding ways in which groundwater supply and demand can be balanced through a combination of enhancing aquifer recharge and constraining consumptive use in agriculture.