In 1938, the French colonial authorities in what is now Mali launched an ambitious infrastructure plan to transform the desert into an agricultural production area. Water was diverted from the Niger River by a system of canals to allow the irrigation of more than a million hectares of fertile land. Covering over 100,000 hectares in the long term, this project remains one of the largest irrigated areas in Africa.
The Malian project says “Office du Niger”, has had a profound influence on agricultural water management and planning across Africa since the mid-20th century. In the 1960s, African governments saw it as a model of rural development.
With the World Bank funding, hundreds of dams and large irrigated areas have been set up across Africa. The objectives were to increase food security, reduce poverty and stimulate economic growth. Unfortunately, the reality of many of these irrigation projects has been very different.
Since 2008, in response to rising food prices, governments across Africa have announced plans for a new era of irrigation system development. Yet it is still unclear why past programs fell short of expectations. To answer this question, we evaluated the performance of 79 perimeters built in sub-Saharan Africa between the 1940s and 2010.
Our research reviewed the initial objectives for the agricultural production areas, as indicated in the project planning documents. These were compared to estimates of the amount of irrigated land projects currently supported. The estimates were derived from high resolution satellite images.
Our results show that these irrigated perimeters provide on average only 18% of the irrigated production area that they initially offer. And many projects are now completely inactive – some only a few years after construction. There appears to be little evidence of improved diet performance over more than 60 years.
Research on individual projects blamed a number of factors for the failures of irrigation projects. These include regime size and climate. Arguing that large projects that experience more variable climates fail more often. This was largely not the case in our analysis of 79 projects.
Instead, we found that the main causes of failure were the policy and management frameworks that underpin the development of irrigation projects.
The political first. For governments, one of the main motivations for developing programs was to produce more food. It would also reduce dependence on imports while generating exports. But the resulting emphasis on the production of low-value staple foods harvests – like rice and corn – have often led to poor financial performance.
Low-value crops undermine the financial viability of long-term capital-intensive irrigation projects. Indeed, these crops do not always generate reliable and substantial benefits on the land allocated within the perimeters. And that makes it more difficult for farmers to contribute to the maintenance and upkeep of infrastructure.
The result is a cycle of dependence on foreign investment and subsidies. After that initial investment is used up, many diets quickly deteriorate.
Second, donors have tended to prefer large, centrally managed infrastructure projects. They appear to be less technically and logistically complex than a multiplicity of smaller-scale initiatives. Unfortunately, many centralized government agencies in sub-Saharan Africa are underfunded and poorly endowed with resources. Many lack the technical and institutional capacities to manage such large-scale projects.
At the same time, donor preferences for scale are stimulating the government’s appetite for optimistic plans to secure financial support. As a result, the irrigated areas proposed and the returns to the perimeters are often unrealistic. For example, the Office du Niger only recently reached 10% of the 1 million hectares planned in 1938. On the other hand, the areas intended to irrigate 127,000 hectares around Lake Chad are now completely inactive.
Planners, too, underestimate the costs and overestimate the benefits. Our research argues that without changes in the way projects are envisioned, implemented and managed, African governments risk repeating the development mistakes of the 20th century. This could have negative consequences on poverty, food security and economic development.
Pathways to follow
The failures of large-scale irrigation in sub-Saharan Africa have been recognized for several decades. But our research suggests that this has had little impact on how planners or governments approach such projects.
Considering the actual results obtained, it can be argued that many large-scale irrigation projects have not generated a return on investment. Even those that were initially viable have since swallowed up funds for maintenance and rehabilitation. Greater and more systematic performance monitoring and accounting is needed to address these issues.
To do this, governments, donors and researchers can use new data sources such as satellite imagery. Equally important are planning process reforms to ensure that investments are conditional on positive and sustainable results for farmers and communities.
At the same time, we are also proposing to rethink the historical preference for large projects. Are they the best or the only way to increase either food security or farmers’ incomes?
It is increasingly recognized that farmers across Africa are very enterprising. This is highlighted, for example, by the recent increase in attention within the World Bank and other agencies on farmer-led irrigation. Small farmers have for many decades and even centuries have developed a wide range of irrigation systems independent of development agencies or governments.
Evidence suggests that these investments can be orders of magnitude cheaper than large programs. These can provide better returns in terms of farmer incomes and rural livelihoods.
Investments in large-scale water infrastructure will continue to be an important means of agricultural production. This is all the more true as the availability of water becomes increasingly irregular in many regions due to climate change and pressures from population growth.
This requires investments in storage infrastructure – both built and natural – to ensure reliable access to water. This in turn provides a basis for encouraging farmers to invest in irrigated agriculture, thereby reducing the risks associated with adopting new technologies or practices.
It also requires new approaches to how irrigation development is financed and implemented in Africa. There is a need to combine large and small scale approaches to irrigation development to achieve the dual objective of improving food and water security.