Small-Scale Solutions: Rainwater Harvesting Tanks

Rainwater harvesting is becoming increasingly popular around the world. The process simply involves collecting water from the surface where it falls and storing it for later use in special tanks (Sustainable Earth Technologies). Individuals are installing harvesting systems in their homes to help reduce their water consumption, such as in the UK (featured in this Guardian article). In Australia, rain harvesting tanks are considered by many to be their main source of water (The Water Project). 

While this may be a way to save money and the environment for developed nations, it has the potential to save lives by providing a water source and food security elsewhere. In Africa rainwater harvesting is becoming an important tool for facing water scarcity due to climate change. Small-scale rainwater harvesting tanks collect water that can be stored locally in a variety of ways, losing less to evaporation than larger-scale infrastructure. An example tank in Uganda is shown below, where water is collected through gutters and stored in a cylindrical tank. 

UN Photo: Rainwater Harvesting Tank, Uganda

Despite Africa being an arid continent, thought of as water scarce, the overall quantity of rainfall across the continent is equivalent to the needs of 9 billion people (UNEP). This rainfall is lost through runoff, but tanks can catch and collect this water. Stored rainwater can then be used for irrigating land for agriculture, as well as for domestic purposes. The tanks provide clean freshwater as rainwater falls straight into tanks and isn’t contaminated in any way. Rainwater harvesting also has the benefit of buffering against drought events by supplying a consistent water source. UNEP argue in their report that the water crisis in Africa is due to economic lack of investment, rather than a matter of physical scarcity. Investment into rain harvesting tanks would help water scarce regions develop and also face future climate uncertainty. 

UNEP's report states that Kenya receives enough rainfall to supply the needs of 3 or 4 times its 40 million population. Kenya is also doing better than most of its neighbouring countries in developing and adopting these technologies (Purcell). Irrigation has greatly expanded through the use of harvesting tanks and other small-scale irrigation projects. Farmers are then able to have 2-3 crops a year, increasing their per hectare gross margins. Women, who do the most field work, also gain greater earning potential, while also saving time collecting water from far away sources. Kenya has vast potential to expand this technology and see more positive benefits. 

Ethiopia is also newly experiencing the rewards of rainwater harvesting schemes. Awulachew points out that ‘frequent dry spells and droughts exacerbate the incidence of crop failure and hence food security and poverty.’ The lack of water storage capacity combined with large spatial and temporal variations in rainfall mean most farmers can only produce one crop a year (IWMI). Through simple rainwater harvesting equipment larger crops are being produced and, again, women are more empowered. 

The benefits of small-scale solutions such as rainwater harvesting are clear to see. Food security is ensured through irrigating land to produce more crops, a source of water is available even in times of drought, with the additional benefit of empowering women and promoting gender equality. As Africa’s climate variability becomes more severe in the years to come, projects such as these will be vital to water availability and food security. Schemes will be even more successful when local businesses produce, build and install the rainwater harvesting tanks themselves as opposed to being externally funded through charity. Employment is created, profits can be fed back into the community and there is a sense of ownership over the tanks ensuring their longevity.