ISSN (Print) - 0012-9976 | ISSN (Online) - 2349-8846

Articles by M Dinesh KumarSubscribe to M Dinesh Kumar

Impact of Water Harvesting and Recharge: A Rejoinder

This note argues that the critique "Water Harvesting and Recharge: A Misinterpretation" (29 November 2008) of "Chasing the Mirage: Water Harvesting and Artificial Recharge in Naturally Water-scarce Regions" (30 August 2008) is erroneous in its reading of the latter's arguments on the impact of water harvesting and recharge.

Chasing a Mirage: Water Harvesting and Artificial Recharge in Naturally Water-Scarce Regions

The analysis presented in this paper shows that in water-scarce regions of India, run-off harvesting does not offer any potential for groundwater recharge or improving water supplies at the basin scale. The issues are many: (1) Water harvesting in the "closed" basins have downstream negative hydrological impacts. (2) Due to high inter-annual variability in rainfall and therefore run-off, during drought years the water harvesting structures have become highly unreliable, whereas an attempt to capture run-off during wet years would remarkably increase the unit cost of harvesting water. (3) In closed basins, intensive water harvesting would lead to negative welfare outcomes due to high negative externalities at higher degrees of basin development. (4) Even at the local level, physical efficiency of water harvesting is likely to be poor, mainly due to groundwater-surface water interactions and the poor storage capacity of hard rock aquifers underlying most of the water-scarce regions. The artificial recharge systems in natural water-scarce areas in India are economically unviable. Also, the much talked about virtues such as promoting equity in access to water, social justice, water security for the poor, and realisation of greater economic value from the use of water, can be hardly achieved through water harvesting programmes in water-scarce regions, as practised today.

Value of Groundwater

A study carried out in four villages in Banaskantha district of Gujarat estimated that 60 per cent of the net farm output generated through groundwater use in agriculture came from dairying. Tubewell irrigation supports three-quarters of the farming household income in these villages and, strangely, this share is larger for water buyers and farm labourers than for tubewell owners. This is despite the fact that tubewell irrigation costs have soared rapidly with depleting water tables. Despite the high costs and depleting water tables, irrigated areas have increased steadily, making livelihoods even more precariously dependent upon sustainable groundwater management.

Narmada Water for Groundwater Recharge in North Gujarat

North Gujarat is naturally endowed with one of the richest alluvial aquifers of India but its uncontrolled exploitation for irrigation has resulted in many undesirable consequences. A major hydrological opportunity for rejuvenation of the aquifer system is provided by the availability of unutilised flows from Narmada basin. It is proposed to divert this water to north Gujarat through the Narmada main canal, and use the existing canal networks and village ponds and tanks in the region to activate a decentralised recharge process. This paper examines its physical and economic feasibility. An evaluation of two recharge scenarios in north Gujarat shows that using pumped water for recharging outside the designated command area may prove to be an uneconomical proposition, unless there is substantial increase in the productivity of water. Recharge within the command would be much more economical.

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