Kenya needs to improve its rainwater harvesting systems

Kenya has “500 cubic metres per capita” of water storage and fails to match the required amount of “1,500 cubic metres per capita”. This is what it needs to look into to improve its situation.

Kenya, Rainfalls, Rainwater Harvesting
Kenya could make better use of its rainfalls. © Robin Hartwell (Pixabay)

This year Kenya has witnessed “torrential rainfall”, writes the Theme Leader of Water Management at World Agroforestry Centre, Maibo Malesu. However, at the wake of pouring rain came devastating droughts which hit some “parts of the country”.

In conversation with Moina Spooner, from The Conversation Africa, Maimbo Malesu talked about ways in which Kenya could make better use of its rainfalls. First up the list was rainwater harvesting which requires capturing, storing and using of rainwater. It is an easy method viable to all easily adaptable to “local context”.

Amid many types of “rainwater harvesting systems”, three stand out. The first one is in-situ rainwater harvesting wherein the rainwater is captured at the place it falls, useful for agriculture as micro-catchment areas. Giving an example, Malesu mentions the Zai pits, “small permanent micro-basins, excavated on the ground” where the crop is planted. This process also prevents soil erosion.

The second method is called “run-off catchment systems”, wherein the rainwater falling on ground surfaced are channelled to a storage structure for collection in the form of either “anks, ponds, pans, sand dams” or earth dams. Moreover, on taking a quick glance at the “national rainwater harvesting schemes” of Kenya, it would appear that the government seems to favour the second rainwater harvesting option in dam forms so as to serve a wide population. While, Malesu further added that:

“The cost per capita is lower with large dams and they are multi-purpose; they can generate hydro power generation, supply water and be used for recreation. But the water distribution system is expensive and difficult to maintain. For example, 40% of treated water in Nairobi is lost through leakages from old pipes, illegal connections and outright theft”.

However, the third system is the “roof catchment systems” and the name suggest here the rainwater running from the rooftops is collected in a tank “either above or below” ground.

When asked about Kenya’s performance in thearea of rainwater harvesting as a national as well as household level, Malesureplied: “In terms of water storage per capita peryear, in Kenya it’s about 500 cubic metres per capita, but should be 1,500cubic metres per capita. This is a minimum figure which takes into account allrequirements for domestic needs including food and clothing. In the US it’sabout 5,000 to 6,000 cubic metres per capita storage per year. In Ethiopia it’sabout 67.

“In the capital Nairobi water security – in terms of meeting demand and storage capability – is very low. The city has to meet a demand of 770,000 cubic metres a day and the current supply is 550,000 per day. But only half gets to the public. About 40% is lost”.

Among the major hurdles faced by Kenya in its rainwater harvesting efforts are the financial constraint, capacity issues coupled with policy decision, “lack of market knowledge”, and the technical difficulties.

The World Agroforestry Centre is working to popularise rainwater harvesting practice in “sub-Saharan Africa” with the help of a “southern and Eastern Africa network” including twelve countries. This way, the countries that are part of the network learn from each other. When it comes to “small-holder and domestic systems” Kenya is a leader in the network. However, the effort seems to stop at pilot level; although, Ethiopia can provide valuable examples in watershed management.

Furthermore, managing agricultural lands brings down the risk of flooding, while Kenya’s river harbours “a lot of soil in river systems”, which as Malesu explains “means the speed of the water increases, soil is deposited downstream and the risk of flooding increases in the lower parts of the landscape”.