Together with Ethiopia’s Haramaya University, Unesco-IHE has started a unique master course in an ancient yet nearly forgotten form of water management, called spate irrigation. The first six students started their two-year course in Alemaya last September.
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In spate irrigation, everything works differently. Most irrigation works make use of continuously flowing (perennial) rivers to moisten the crops on an almost continuous basis. Spate irrigation however uses the wild and muddy waters from rivers that appear only sporadically. The sudden floods or spates that rush from the mountains inundate the lands with perhaps as much as a metre of water. Only then crops are sown: cereals and oilseed but also cotton and even vegetables. Typical spate irrigation sites are the arid flatlands at the foot of mountains in South Asia, the Middle East, North Africa and the Horn of Africa.
“Spate irrigations are among the most fascinating and complex water management systems,” says specialist Frank van Steenbergen, from the MetaMeta consultancy agency. “It’s like a virus: once you’ve been infected with it, you can’t get rid of it.” Rudolph Cleveringa, senior technical advisor with the International Fund for Agricultural Development (IFAD) in Rome, shares Van Steenbergen’s fascination: “Once infected with the spate irrigation virus, I began to dig up who-is-who and what-is-what in spate. What was an innovation for me turned out to be a centuries-old, well-balanced system of land and water rights.”
“The main focus of the Master’s education,” says senior lecturer, Dr Abraham Haile Mehari, of Unesco-IHE, “is to make clear how different spate irrigation is from perennial irrigation in its design, management, hydrology, operation and management. Once the students know these differences, they can design with a broader knowledge.”
Unesco-IHE, MetaMeta and IFAD have joined forces in the Spate Irrigation Network, which aims to reinvigorate this nearly forgotten type of water management, in order to share the best practices and spread knowledge locally to practitioners. The network focuses on Ethiopia, Sudan, Yemen and Pakistan.
Currently the area under spate irrigation is estimated at 2 to 2.5 million hectares (half the size of the Netherlands). In future, more farmland is expected to become spate-dependent as a consequence of deforestation (less water is retained) and depletion of ground water reservoirs.
Surging mud
Frank van Steenbergen saw spate irrigation first in Belugistan, in the northeast of Pakistan, twenty years ago. The enormous waterworks astonished him. He saw large earthen barricades, 10 to 15 metres high that bulldozers had build right across a dry riverbed. In Eritrea, where they lacked such machinery, people even used oxen with scraperboards to draw mud up the dam, and then fortified it with scrub.
Once the river rose and the flood waters came, the large dam blocked the stream and forced the water sideways onto the farmland. The water streamed along earthen weirs, 2 to 3 metres high and some kilometres long, until it had finally lost its momentum and spread evenly over the land. “You can only use the water once it has lost its speed,” Van Steenbergen explains. “Or, as the Pakistanis say: ‘You must kill the flood’. Otherwise the soil will simply be washed away.” Once the fields are firmly inundated, a berth is made in the main barricade. The river then surges through it and rushes on to the next barrier and the adjacent farmlands. And so on.
If this seems all perfectly sensible, the trouble comes after a few years when the sediment from the stream (sand can account for up to 10 percent of volume) builds up on the fields and raises them above the river’s flood level. Farmers know that, as they are used to moving to new fields every five to ten years. They adapt to nature. “Spate irrigation is a Taoist form of water management,” says Van Steenbergen. “It merely makes use of nature, rather than trying to control it, which is the more traditional Confucianist style of water management.”
What Rudolph Cleveringa saw some ten years later in the Gash region around Kassala, in Sudan, was a spate irrigation scheme gone into decay. “Getting a piece of wetted land was a lottery with over 72,000 people buying raffle tickets in an overloaded system. The irrigation couldn’t be mastered like good-old surface-water take-off. The canals were clogged, bridges were drowned, and distribution works didn’t work as designed.” He noticed that drinking pools for livestock were filled with sand instead of water, huge pools of invested water had formed in the lower lying areas, and the inner delta at the end of the river “was dry with a capital D”.
The Government of Sudan had requested IFAD to help and rehabilitate the irrigation works. Cleveringa recalls: “After extensive consultations and negotiations with government officials, local stakeholders and farmers, a fully-fledged livelihoods regeneration support programme was finally agreed upon in 2003.”
The rehabilitation programme was as much about resolving land and water rights and having people assume collective responsibility for the canal operation and maintenance, as it was about civil engineering, like reconstructing river intake weirs and setting up distribution works on secondary channels.
Looking back over the eight years since the beginning of the Gash Project, Van Steenbergen summed up the intermediate results in his report for IFAD: two-thirds of the targeted 100,000 hectares had been reopened for spate irrigation; settlements of disputes were respected; the production of sorghum had risen by a modest 8 percent but fodder by 60 percent. The cattle stock of the semi-nomadic population had grown by 12 percent and milk production by 62 percent. All in all, the region could provide 80 percent of its food requirements – which is quite an achievement compared to the ‘serious threat to the livelihood’ that Cleveringa had encountered eight years before.
Restoring knowledge
Although spate irrigation probably dates back to biblical times, much of the knowledge seems to have evaporated over the last generation. Part of the explanation for this is that spate irrigation was outflanked by perennial irrigation, in which western engineers excelled. If indeed water management specialists were aware of the strange customs of diverging floods onto the fields, they perceived it as a risky and an unpredictable practice. Plus, says Mehari, they regarded it as a subsidence system of marginal economic importance.
As a consequence of this neglect, most practical grassroots knowledge of how to kill the flood, how to arrange access to land and water, and how to prevent the whole system from silting up was largely forgotten.
Like rare seedlings in a nursery, six students have now enrolled in the new double Master’s course of ‘agricultural water management in (semi) arid regions’. They students come from Ethiopia (three), Sudan, Yemen and Pakistan (one each), on a grant from IFAD. These students are to become the ambassadors of spate irrigation, says Mehari. “They will learn about the design of irrigation structures; the management of these, including social and institutional aspects. It will be a comprehensive programme.” After their initial three months at Haramaya University, in Ethiopia, the students will be taught at the Delft Institute for Water Education for nine months. Their research project (half a year) takes place in their homeland. It will focus on a practical spate irrigation issue. Thus, the spate irrigation network hopes to strengthen the regional nodes and to develop and disseminate knowledge into the regions were it is needed most.
The ambitions of the spate irrigation network go well beyond subsidence farming. Indeed, spate irrigation can germinate a green economy, says Cleveringa. “Simply said, environmental flows can recharge aquifers, enable carbon sequestration, increase biodiversity and keep the habitat for further beneficial exploration. That’s what happening in the Gash.”
“With spate irrigation you can develop range lands, you can develop agro forestry and recharge ground water,” Mehari adds. “Spate irrigation can be the key to developing a local economy. Waterworks alone are not sufficient; it should be part of the bigger livelihood picture. Then you get investments, and agricultural products get a value. Once people gain access to the market, a green economy starts rolling.”
