Low-cost water harvesting structures for groundwater recharge

Widespread adoption of community-built structures in Rajasthan

Background

Uneven, erratic rainfall and long dry spells are common prevailing weather conditions and this adversely affect kharif crop growth in southern Rajasthan. To combat this uncertainity associated with rainfall, farmers have evolved different area- specific indigenous water harvesting systems. These structures are simple, cost-effective and easy to implement. However, owing to poor design and construction these structures fail regularly. To address this problem, a project involving the design and construction of water-harvesting structures was implemented in Shishvi village, Girwa Panchayat Samiti, Udaipur district.

Stakeholders

All India Coordinated Research Project on Groundwater Utilisation, Directorate of Water Management, ICAR, Bhubaneswar supported the project financially. Students of Agricultural Engineering undertook site selection and topographical surveys of
the catchment and submergence areas. Farmers and communities of southern Rajasthan participated and provided on-field support for proper implementation of project.

Approach and Methodology

The project aimed at (i) Identification of suitable rainwater harvesting technologies for the arid and semi-arid regions of Rajasthan; (ii) Design and development of dry stone masonry type low-cost water harvesting structure; and, (iii) Evaluation of the effectiveness of the structure for augmenting groundwater recharge. The intervention involved planning, design, and construction of a low-cost dry stone masonry structure, useful in augmentation of the groundwater table through continuous recharge. Such structures can effectively harvest rainwater, with a maximum micro catchment
area of 50 ha.

The designed technologies considered all major factors such as peak rate of runoff, height, volume of storage, provision of spillway and stability. A cross-sectional view of the low-cost dry stone masonry structure is given in Fig 1.
The selected project area, Shishvi village, is a narrow section of the valley, with a catchment area of 4.25 ha. Due to hilly topography, stones were readily available in the area (See Fig 2). Construction of structures involved local stone and conventional skills of the community. Its impact in terms of life-saving irrigation and groundwater
recharge was assessed between 2010-2013.

Due to its relatively easy construction, community played an important role in formation of these structures. With some off-campus technical training, a group of farmers could build these structures in a series in the valley. The dry stone masonry type structure was six times cheaper than the conventional masonry water harvesting structure.
The cost of constructing a 10 metre span with 2 metre height was merely INR 25,000, 90 percent of which was the labor component.

Screenshot (52)

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