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Modernizing rainwater harvesting for the dry areas

Nov 26,2017

Water harvesting in Jordan using laser-guided Vallerani machines

Although there is renewed interest in indigenous rainwater harvesting, traditional practices and technologies are rarely suitable or feasible. ICARDA is promoting a practical and cost-effective alternative that combines indigenous knowledge with mechanization to enhance effectiveness and strengthen resilience.

Although rainwater harvesting remains relevant, there have been few efforts in recent decades to modernize old practices, develop new ones, or create an enabling environment to unlock its full potential. Many rural communities have become overly attached to old practices and all too often the concept of rainwater harvesting is blamed for failure when in reality mismanagement and poor design are most at fault.

The limitations of rainwater harvesting

One key limitation is that the technical aspects of water harvesting structures – never simple and often complex – are usually implemented by unskilled labor. Laying ridges or contour lines is essential to the proper functioning of a water harvesting system, but this is a complicated procedure and requires special training. Proper site selection is also required. Failure to adequately tailor a method to site characteristics – topography, soil type, vegetation cover etc. – will result in failure.

In addition, the contextual environment in the drylands is increasingly unfavorable. The break-down in collective conservation systems, subsidized feed, and a corresponding increase in animal populations and overgrazing means that unless new legislation is introduced and existing institutions are reformed dry ecosystem restoration schemes will have limited success.

A practical and cost-effective approach

In an effort to overcome these constraints, ICARDA scientists worked with two communities in Jordan’s badia - Mhareb and Majdieh - to design, test, and promote a practical rainwater harvesting package. The package combines indigenous knowledge with mechanization and a contour laser guiding system to enhance the accuracy of ridges and bunds.

Efforts were also taken to improve the selection of restoration sites, design appropriate structures, select the right shrubs, and most importantly, implement sustainable grazing strategies and ensure on-going maintenance.

With support from Jordan’s National Center for Agricultural Research and Extension (NCARE), 80% and 90% of farmers in Mhareb and Majdieh used the package. Jordan’s Ministry of Environment also adopted it, allocating funds for its implementation across 2000 Ha so far – an area the Ministry is planning to extend even further.

The result? Rapid vegetation growth, more animal feed, less soil erosion, and enhanced biodiversity. The package is also cost-effective: it costs a mere USD 32/hectare – which includes the production, planting and maintenance of shrub seedlings – and the economic internal rate of return is estimated at some 13%.

Achieving long-term sustainability

While the positive impacts of the rainwater harvesting package are clear, additional financial support is needed to extend the intervention over a wider area and ensure its long-term sustainability. Given that local communities are unable or unwilling to fully cover the costs of implementation, public funding is essential.

However, to extend benefits and reduce costs even further, public-private partnerships should be initiated to pay for the building of water harvesting structures. This would enhance the intervention’s viability across the dry areas and ensure that many more rural communities could benefit from land restoration and enhanced resilience to climate variability and change.

This blog is based on an article recently published in the Journal Environmental Reviews: ‘Rainwater harvesting for restoring degraded dry agro-pastoral ecosystems; a conceptual review of opportunities and constraints in a changing climate.’