Water Harvesting in Sub-Saharan Africa
Format: PDF / Kindle (mobi) / ePub
Agriculture in Sub-Saharan Africa is constrained by highly variable rainfall, frequent drought and low water productivity. There is an urgent need, heightened by climate change, for appropriate technologies to address this problem through managing and increasing the quantity of water on farmers’ fields – water harvesting. This book defines water harvesting as a set of approaches which occupy an intermediate position along the water-management spectrum extending from in situ moisture conservation to irrigated agriculture. They generally comprise small-scale systems that induce, collect, store and make use of local surface runoff for agriculture.
The authors review development experience and set out the state of the art of water harvesting for crop production and other benefits in Sub-Saharan Africa. This includes an assessment of water harvesting schemes that were initiated two or three decades ago when interest was stimulated by the droughts of the 1970s and 1980s. These provide lessons to promote sustainable development of dryland agriculture in the face of changing environmental conditions. Case studies from eight countries across Sub-Saharan Africa provide the evidence base. Each follows a similar format and is based on assessments conducted in collaboration with in-country partners, with a focus on attempts to promote adoption of water harvesting, both horizontally (spread) and vertically (institutionalization). Introductory cross-cutting chapters as well as an analytical conclusion are also included.
further by discussing in greater detail the publications from the last two decades. The reason for going back several decades is that important older studies, reviews and assessments are in danger of ‘disappearing’. This is partially because many have not been digitized (and thus web-based searches will overlook them or not provide access to content), partially because there is a tendency to ignore what has been done before (with ﬁeld research often more appealing than an analysis of insights
dynamics in African farming systems, International Institute for Environment and Development, London. Howell, T. A. (1990) ‘Grain dry matter yield relationships for winter wheat and grain sorghum—southern high plains’, Agronomy Journal, vol. 82, pp. 914–918. Hudson, N. W. (1971; 1981, 2nd edition) Soil Conservation, Batsford, London. Hudson, N. W. (1987) ‘Soil and water conservation in semi-arid areas’, Soils Bulletin, no. 57, Food and Agriculture Organisation (FAO), Rome. Hudson, N. W. (1991) ‘A
Southern Africa, and in general poor household are usually constrained in their access to markets, which is an important reason why they remain poor (Duﬂo et al., 2011). These households are also faced by other constraints, including lack of assets, entitlements and property rights, but it is outside the scope of this chapter to fully discuss the role of poverty in inﬂuencing water harvesting adoption and uptake. Still, Barbier (1990) illustrates the crucial role of land tenure security for
(rainfall below 100 mm/year). The remaining part of the country is divided between the Sahelo-Saharan zone (annual rainfall between 100 and 300 mm) and the Sahelian zone (where annual rainfall ranges from 300 to 600 mm). Only a small fraction of the south-western part of the country receives more than 600 mm rainfall. Rainfall is characterized by high variability, both in time and in space. It is erratic and often occurs in isolated showers. The average annual temperature reaches 29°C. The
not necessarily (all) related to direct foreign investment, increased from 287.5 in 1990 to 422.2 in 2007; that is, an annual growth of 1.9 per cent in 2000–7, coming from 2.8 per cent in 1990–99 (FAO, 2012). Just over 50 per cent of the capital stock concerns ﬁxed assets for livestock and 25 per cent includes land development and improvements (fences, ditches, drains, etc.; FAO, 2012). It is difﬁcult to get a clear picture of the distribution of investments in waterrelated technologies for