Rainwater harvesting (RWH) allows storing irrigation water for critical times in the growing period of otherwise rain-fed crops. It is also a promising practice for reducing costs for irrigation uptake as its installation is considerably cheaper than building groundwater irrigation infrastructure.
In Ghana, limited evidence on the use and potential of RWH for small-scale irrigation systems exists. Even though Ghana has abundant water resources for irrigation, its uptake is very low. RWH can provide a cost-efficient alternative to irrigation installment and is notably a strategy with usage potential at different scales. It is particularly well suited to be coupled with farm-level horticulture production, either for additional income from vegetable sales or satisfying changing demands in household consumption (for Sub-Saharan Africa as a whole, see e.g. OECD & FAO, 2016). This could also yield nutritional and thus health benefits, with vegetables enriching otherwise staple-based diets in Ghana. A combination with conservation agriculture techniques can be particularly useful, with further improvements in soil water storage capacity enhancing the water use efficiency of RWH.
In addition, RWH has the potential to deliver gender co-benefits. Since it is usually women who are in charge of fetching water and who engage in backyard vegetable farming, collecting rainwater could save women time, making time for other activities and enabling additional farming activities.
Rainwater harvesting and small-scale irrigation are a good alternative for action at smallholder level, with simple installation techniques proving less difficult to implement, maintain and refinance as compared to large-scale irrigation systems.
Thus, RWH is a promising adaptation strategy meeting local interest in Ghana. It can be implemented by farmers autonomously and decrease dependency on precipitation.
- OECD/FAO, (2016). Agriculture in Sub-Saharan Africa: Prospects and challenges for the next decade, in OECD-FAO Agricultural Outlook 2016-2025, OECD Publishing, Paris. https://dx.doi.org/10.1787/agr_outlook-2016-5-en.