Irrigation Limitations

Worldwide, the extent of irrigated land between 1961 and 2009 more than doubled. If yields increased, so have the number of the world's river basins reaching conditions of water scarcity, where it is estimated that more than 40% of the world's rural population lives (FAO, 2013). 

Irrigation eliminates farmers' dependency on rain patterns and allows for a second cropping season. Reliable water supply also allows smallholders to diversify their production and perhaps grow higher value crops. Despite the intensifying focus on irrigation and large-scale infrastructure developments in SSA, small-scale irrigation schemes have a vital role to play and cannot be underestimated. Recent studies (Burney et al., 2013; Bjornlund et al., 2017; Woodhouse et al., 2017) have concluded that small-scale distributed irrigation systems, as opposed to a centralized infrastructure, are more efficient in the SSA context since they are self-managed, less costly to build and maintain. 

Most countries in SSA have little access to irrigated land and efforts must be made to level the playing field so as to enable low-income farmers to diversify their crops. Presently, resource-poor household are incapable of diversifying production and cannot escape the subsistence farming "trap". They frequently make decisions based upon the appearance of plants: "as a result, some farmers are likely to over-irrigate, leading to nutrient leaching and reduced productivity, while others are likely to under-irrigate due to the high cost of fuel, resulting in yield losses" (De Sousa et al., 2017)

While development cannot be achieved without economic growth, overemphasizing economic development often undermines environmental stability and the long-term benefits of development. Large-scale development projects and macroeconomic reforms have ''all too often jeopardized poor people's livelihoods by destroying the resource base'' (IUCN, 2008). 

The Waza Logone floodplain, in the northern province of Cameroon, was designated a Ramsar Wetland of International importance in 2012. In a semi-arid ecosystem where rainfall is variable and livelihoods insecure, the wetland provides abundant natural goods and services which the rural population heavily depend on. In fact, wetlands account for around 86% of the country's freshwater surface area and are a crucial asset for dry-season farming and irrigation. However, the productivity of the Logone floodplain largely depends on the annual inundation of the Logone River. Irrigation schemes, with the construction of dams and canals within and upstream floodplains in Cameroon, have severely affected floodplain hydrology and ecology and undermined the livelihood security of fishers, farmers, pastoralists. 

Source: IUCN, 2008

In 1979, the construction of a small irrigated rice scheme (40 km²) reduced flooding by almost 1,000 km², almost 30% of the original flooded area. The socio-economic effects of this loss are estimated at around $50 million over approximately 20 years, with up to 8,000 households directly experiencing losses of more than $2 million a year through the reduction of dry-season farming, natural resource harvesting and surface water supplies (IUCN, 2008). The economic, environmental and social losses, therefore, largely exceeded the anticipated benefits of irrigation. 

The Sanaga River, which stretches along the South, Centre and West provinces, is the primary water source in Cameroon and currently has two dams. As part of the plans to become an emerging economy by 2035, Cameroon (with the help of development partners) is investing in increasing its energy system with hydroelectricity generation. The government has planned the construction of 3 additional dams along the river and its tributaries, which will supply a major part of the country's energy needs. Are there trade-offs between ''unlocking'' the energy potential and long-term sustainability/resilience?