Using Water to Grow Food: examples from Ethiopia

Irrigated vegetable fields in Ethiopia (Ejeta, 2019)

Malin Falkenmark developed the Water Stress Index (WSI) following the famines impacting Africa in the 1980s. The indicator calculated improved water supplies able to provide self-sufficient crop production relative to the portion of the population jointly depending on each flow unit of water available to the country from the water cycle (Falkenmark, 1989). It classified different categories of water access, defining absolute water scarcity as 1000 people depending on 1,000,000m3/year (i.e. single flow unit of water). Falkenmark (1989) did recognise the added complications of interannual fluctuations, but the index bears other limitations. The WSI along with other holistic water metrics, defines freshwater resources in terms of Mean Annual River Runoff (MARR), which denies variation of freshwater quantities in groundwater, lakes, dams and reservoirs (Damkjaer and Taylor, 2017). Moreover, intra-annual variations mask scarcity and different national demands create different thresholds (Rijsberman, 2006). A decade later, Ohlsson (1998) modifies Falkenmark’s indicator to include the possibility to adapt to stress through economic, technological or other improvements. This time the indicator is combined with HDI to become the Social Water Stress Index.

To a more interesting extent under our topic, the WSI does not indicate water scarcity for domestic uses. Instead, it exclusively relates to the water used in food production. Water domestically used is recyclable, as it can be returned for reuse (Rijsberman, 2006). Conversely, agricultural use of water consumes it through evapotranspiration, thus preventing reusability (Rijsberman, 2006). Therefore, water accessibility is a determinant for capacity of food production in our study of the African continent. 

After Falkenmark (1989) representation of the categories of water scarcity

 

The 1980s brought consecutive years of famine to Ethiopia. Environmentally, droughts and years of destructive land uses damaged the land. Politically, disputes, failure to gradually resolve issues and external politics delaying emergency relief combined to cause unforgiving circumstances (Li, 1987; Corbett, 1988). The hardest hit region was the northern part of the country, including present day Eritrea. These involve two ecological zones, very different yet similar in its inability to host rainfed agriculture or suitable irrigation schemes. Only dams existed to attempt to cope with these disadvantaged water circumstances and they were directed for irrigation schemes on forcibly established commercial farms of cotton and sugarcane (Kebbede and Jacob 1988).

1999 relief map of Eritrea and Northern Ethiopia

Irrigation practices influence the entire growth process of crops, from soil preparation, germination and root growth to nutrient use, plant development and yield (Novus Environmental, 2019). Despite the enormous potential for enlargement, in 2018, only 6% of Africa’s farmed land was irrigated (Malabo Montpellier Panel, 2018). Through the years, reports have found repeated scenarios where irrigation has increased crop yield in formerly rainfed farms (Dhawan, 1985). Accordingly, irrigation is a significant promoter of economic growth and rural development, and with it, environmental burdens related to water abstraction, energy consumption, and pollutant depositions may be reduced (Levidow et al., 2014). For instance, Hagos et al., 2009 found that irrigation only contributed 5% to the Ethiopian national GDP while crop production contributed 28%. Comparatively, in Sudan irrigation contributes to about 50% of the crop production and in Egypt irrigation dominates agriculture (Hagos et al., 2009). The research suggests that contribution from irrigation systems to national economies would increase by enhancing the provision of agricultural inputs, promoting high value crops, creating appropriate market conditions and increasing  the efficiency of small and large schemes. In addition, irrigation provides a protective margin from droughts by stabilising incomes of farmers working on irrigated land (Dhawan, 1985). Thus, in the Anthropocene, irrigation development would suppose a significant advantage to cope with the adverse effects and challenging conditions of a changing climate (Malabo Montpellier Panel, 2018). 

After Awulachew et al., 2007 map of the existing irrigation programmes

Ultimately, water and food become tightly linked from the first steps of production. Intra-annual variability of water may be fatal when it reaches extremes such as drought levels. Thus, it is essential to consider its distribution through space and time, and it is even more crucial to appreciate the limitations of holistic indicators. Irrigation provides a solution to such variability while it is able to boost the economy of certain African countries and has the capacity to alleviate some of the impacts induced by climate change. The potential for new irrigation schemes in Africa may still be further exploited to reach its full benefits. 

NB: While we took the time to focus Ethiopia, I encourage to read more about the current genocide occurring in Tigray. For those in London, a protest will take place the coming 7th of November 12pm at the US embassy, 1 year after the beginning the genocide