ICARDA Caravan, Issue No. 23

Focus

The Vallerani Water Harvesting System

Akhtar Ali, Theib Oweis, Atef Abdul Aal, Mohamed Mudabbar, Khaled Zubaidi, and Adriana Bruggeman

The badia is the traditional grazing ground of the native herder population in Jordan and Syria. These rangelands cover over half of Syria and 90% of Jordan; but increases in sheep numbers have left the badia in varying stages of degradation. In Jordan, plowing of rangelands for barley cultivation has added to the problem. Badia areas generally receive less than 200 mm of rainfall per year, largely in a few heavy showers. Degraded land is unable to absorb the rainwater, so much of it is lost to runoff and evaporation. Surface flows also carry away valuable topsoil. During the hot, dry summer, wind erosion further degrades these fragile lands, and wind-blown dust affects the environment and the health of the population.

The Vallerani plow at work in Jordan.

Tractors, engineering savvy, and community participation… the Vallerani water harvesting system is helping to rehabilitate degraded rangelands in Syria and Jordan.

Water harvesting systems can help capture runoff flows and rebuild vegetation in degraded areas. One promising option is the Vallerani mechanized system, a special tractor-pulled plow that automatically constructs water-harvesting catchments, ideally suited for large-scale reclamation work. ICARDA first tested this system successfully for several years in the Syrian steppe, in collaboration with the General Commission for Scientific Agricultural Research (GCSAR). The next stage, scaling out to more communities, involves additional partners including the National Center for Agricultural Research and Technology Transfer (NCARTT) in Jordan. In cooperation with GCSAR and NCARTT, the system is being tested with three communities in Jordan and Syria.

Qaryatein is a low-rainfall (120 mm per year), highly degraded area at the center of the Syrian badia. The land is owned by the state, but herders have communal grazing rights. The community nominated 20 farmers to work with project researchers to plan and implement the interventions. Using the Vallerani system (see box), about 10,500 fodder shrubs were planted on a 100-hectare area within a small 2.5 km2 catchment. Over 85 km of contour ridges were made in just four days!

Sheikh Hilal is a small community on the edge of the Syrian badia, 100 km northeast of Hama. Its 200 families depend on livestock, but the rangelands provide adequate grazing only in spring; animals require supplementary feeding during the rest of the year. The community worked with project staff to plant 2000 fodder shrubs on an area of about 35 hectares. The Aga Khan Foundation is a key partner at this site.

The site in Jordan is located 65 km southeast of Amman, among the small badia communities of Mharib and Majedieh. Average rainfall is 150 mm per year, falling mainly in intensive showers. The soils are poor in structure, with moderate permeability, and they form a thick surface crust when exposed to rain. Gullies are common, reflecting the high rate of soil erosion. Some of the local families are nomads, traveling long distances with their flocks (especially in summer) in search of feed, because the area provides grazing only for 3-4 months in the winter.

How it works
The Vallerani implement is a modified plow, pulled by a heavy-duty tractor. First, contour lines are marked on the slope. The tractor follows a contour line, and the plow makes a furrow about 50 cm deep. A normal plow on flat land excavates a symmetrical furrow, and earth piles up equally on both sides of the furrow. The Vallerani plow creates an angled furrow and piles up the excavated soil only on the lower (downhill) side. This soil forms a ridge that stops or slows down runoff water as it flows downhill.

The plow can dig a long continuous furrow. Alternatively, as it moves forward, the plow blade can also move up and down (i.e. in and out of the soil), creating a series of small basins, each with a ridge. The size and spacing of basins will depend on the frequency of the up-and-down movement of the plow, which can be adjusted.

When a furrow or pit fills up, the overflow enters the next micro-catchment, flows into the next furrow or pit, and so on. Shrubs are planted in pits along the ridges. With moisture readily available, they grow rapidly, providing livestock fodder and helping to conserve the soil. The furrows/basins also slow down runoff flows, preventing erosion.

The Vallerani plow can ‘treat’ 30 ha in a single day, building scores of micro-catchments. For example, the 100-ha Qaryatein site was developed in 4 days. Preparation of pits and transplantation of shrubs took another 15 days. Once the project had invested in the tractor and the plow, the remaining cost of implementation – layout, planting shrubs, training farmers to build and maintain the system – was about US$1250, i.e. about $13 per hectare. That's a small price to pay for sustainability.

Testing, implementation, and impact
The Vallerani water harvesting system is flexible, offering a range of alternatives. Which alternative is the best? To find out, we tested various combinations at the three sites: continuous versus intermittent contour ridges, closely spaced vs widely spaced shrubs, and closely vs widely spaced ridges (4 m to 12 m apart). With these combinations the size of the micro-catchment varied between 8 and 24 m2. We also compared three indigenous shrubs (Atriplex halimus, Atriplex lecuclada, Salsola vermiculata) and two planting methods (planting seeds vs planting seedlings).

For each experiment, we measured runoff, soil loss, soil moisture, shrub growth, and climate parameters, and the corresponding figures for a ‘control’ plot wher e no water harvesting was done. By the end of the first season, shrub survival rates were 75 to 95% in different water harvesting treatments, but less than 30% in the control plots.

Assessing performance of a water-harvesting treatment at sub-catchment scale.

Capacity building and dissemination are important components of the project, helping users gain the full benefits and creating awareness among non-users. A series of field days showcased the value of the system. Exchange visits, where farmers visit other communities to see similar sites in operation, further accelerated adoption and enabled farmers to share ideas on problem-solving. Formal and informal on-the-job training helped farmers as well as research and extension staff operate the system more efficiently. Stakeholder workshops monitored implementation and impact, and helped disseminate the results widely.

In Jordan, high-level policymakers and development leaders have participated in community meetings at the project site, and are planning to use the system to improve badia areas elsewhere in the country.

Three MSc/PhD researchers are studying different aspects of the system in detail – water management, soil loss, economics of the system, and the social and institutional impacts. These studies will help develop recommendations for optimal design and management, build or strengthen the institutions needed to support such systems, and identify policies that can help poor farm communities combat desertification.

Engineers from ICARDA and NCARTT discuss the design of a water harvesting site in Jordan.

Viva Vallerani
The Vallerani system is named after its inventor, Italian agronomist Venanzio Vallerani. Dr Vallerani is a visionary who believes poverty in dryland areas can be fought by increasing the productivity of marginal and abandoned lands. But desertification cannot be rolled back by hand; and no suitable machinery was available. So he developed a special plow that can build contour ridges and semi-circular water harvesting catchments at user-selected intervals. The system can create up to 7500 micro-catchments per day, dramatically improving rainwater retention and erosion.

At 80 plus, Dr Vallerani still travels around the world to convince donors, development organizations, policy makers, researchers, and farmers of the importance of fighting desertification. Since its inception in 1988, the Vallerani system has been implemented in many countries, including Burkina Faso, Chad, Egypt, Jordan, Kenya, Morocco, Niger, Senegal, Sudan, Syria and Tunisia.

Project staff and farmers at the inauguration of the Qaryatein site.

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Akhtar Ali (a.ali@cgiar.org), Water and Soil Engineer at ICARDA, is coordinator of the Vallerani Water Harvesting Project. Dr Theib Oweis (t.oweis@cgiar.org) is Director of the Megaproject on Water Management and Drought Mitigation at ICARDA. Atef Abdul Aal is National Project Coordinator, GCSAR, Syria. Mohammad Mudabbar is a researcher at NCARRT, Jordan. Khaled Zubaidi is National Project Coordinator at NCARRT. Dr Adriana Bruggeman (a.bruggeman@cgiar.org) is an Agricultural Hydrologist at ICARDA.

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