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The Joy of Water - Why Rainwater Harvesting

Updated: Mar 3, 2021

We are working to ensure that no one is left behind by pushing to achieve Sustainable Development Goal (SDG) 6, the aim of which is that by 2030, we should achieve universal and equitable access to safe and affordable drinking water for all. Read on to find out more about how we are working to achieve this in Bomet County, Kenya.

Did you know that even though we're called Dig Deep, when it comes to providing clean water in our school projects, we choose not to dig at all? Instead, we store water in 50,000 litres worth of giant tanks that are filled by harvesting rainwater. Rainwater is one of the less common sources of drinking water around the world, but it has its place, and particularly in this context there's good reason why we are contradicting our name, and rely on the sky rather than the ground.

Sub-Saharan Africa has a reputation for being arid, but in Bomet County, where we work, there's 1200mm of rainfall per year on average; that's more than the 900mm you'd get in rainy Manchester. This means that rainwater is a viable and very affordable water resource that we can use effectively to supply thousands of people with access to clean and safe water.

Unlike digging boreholes, a rainwater harvesting system is gravity-fed, so there's no need to rely on a pump that could break down, and there are no ongoing expenses to keep the system running. We know that this has been a significant problem to date. Figures vary, but across rural Africa, there are tens of thousands of water points that have broken down, with no prospect of being repaired. Boreholes aren't bad per se, but are typically a more complex system made up of specialised equipment like pumps. These types of systems need networks in place to replace components when they break, and provide technicians to fix the problems. But perhaps most crucially, there also needs to be long-term funding mechanisms in place to ensure that when a pump, for example, does break down, it can be quickly and easily repaired. This is just one of the reasons that Dig Deep chooses to use Rainwater Harvesting systems as a more reliable long-term solution to water access for the people of Bomet County.

In February 2021, Justus Tanui, our head of programmes, caught on video the first of five 10,000 litre water tanks being delivered to Dig Deep's project in Kamegunyet Primary School in Bomet County. Below you can see a video of the joy this delivery brought to the children at this school:

"When the lorry arrived on the school grounds, pupils had been sent to collect water in the neighbour's water pan. There was a spontaneous celebration, with lots of jubilation which is a big sign of appreciation. Their mini Jerrycans were converted into drums and the children burst into a song called "what a joy today?" When I asked them why they were very excited they told me that the fetching of water in the near future, will be something of the past. On behalf of the pupils and parents of Kamegunyet primary school I want to sincerely thanks everyone who assisted the school."

Providing safe and affordable drinking water

Unlike other areas, the Rift Valley region, where Bomet is situated, also has problems with high fluoride levels in its groundwater resources. Fluoride is very difficult to remove without expensive treatments like reverse osmosis, and dangerous when ingested in high concentrations, as it can cause bone deformities. By contrast, so long as the catchment roofs are regularly cleaned, rainwater harvesting provides good quality water, that can be made drinkable by simply disinfecting it with chlorine tablets.

To ensure the water stored in the tanks is safe to drink we also use a simple hydraulic mechanism called a "first flush" that drains off the initial roof runoff before filling the tanks. That first flush is characteristically the most contaminated, so we use this safeguard to ensure it doesn't end up in the tanks or being drunk.

Of course there are also challenges associated with rainwater harvesting. Rain is plentiful, but as we know it can be unreliable, which is why we need such a large storage capacity. At a typical school project we will ensure that there is capacity to store at least 50,000 litres of water. This is because there has to be enough water stored for several weeks' use in case there's a dry spell.

This matters because most women and girls where we work waste hours walking to collect dirty water. This dirty water and poor hygiene spread diseases meaning that even more time is lost to sickness that could have been used to learn and earn. Rainwater harvesting removes these barriers to learning - and for a child this can mean the difference between dropping out of primary school and completing a full education, giving them the opportunity to lift themselves out of poverty.

Written by Joe Hook, Programmes Officer

As always if you have any questions or would like to know more about the work that we do here at Dig Deep please do get in touch. You can reach out to Joe Hook, our Programmes Officer for further information about Rainwater Harvesting via the following email:

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