Community dams aim to build water security in arid Kenya

Thomson Reuters Foundation,

By Kagondu Njagi

Katutihia, Kenya
– Before arriving at Katuthia village in lower Eastern Kenya, a visitor travels through parched countryside, with stretches of land sprouting newly sown crops that are already withering after three days without rain.

Lone herders trailed by cattle and goats cast glance at the skies, hoping rain will fall again soon to fill the drinking troughs. Until it does, some will stop at Katuthia village and join groups of women gathered at the Kasomo dam, all drawn there by the same thing: water.

At the water-harvesting reservoir—built, owned and maintained by the community as an adaptation to worsening drought —both man and livestock share the precious resource until it runs out. Even then, users say they are not worried – when the rainy season comes, the dam will soon be full again.

“I am not very worried if there is no more water because by that time the next rainy season will be around the corner,” says villager Rachel Mwangangi. “I will have stored enough at home to see my family through the brief dry spell.”

Kenya's cycle of extreme weather repeatedly plunges arid parts of the country into drought and then batters those same areas with storms and floods that displace tens of thousands of people every year.

But some, like the Kasomo group in Katuthia village, have discovered they need not be at the mercy of increasingly extreme weather attributed to climate change. Instead, they can harvest the heavy rains and put the water to use during the dry seasons. All they need is the right topography and the labour of a few villagers.


A push to build earthen water storage dams in the region is the result of an effort by a variety of organisations - including the Kenya Climate Change Working Group, the Roman Catholic organisation Caritas Kitui, and government geologists—to find ways to turn floods into water-harvesting opportunities in arid parts of Kenya.

The dam at Katuthia village has been helping the surrounding community survive drought for two years now. The bowl-shaped structure took around 15 days to build and is about the size of half a soccer field. Depending on how much rain falls during the wet seasons, the Kasomo dam can hold enough water to supply the area’s users for up to three months.

It works thanks to Eastern Kenya's geography.

According to geologists, just below the topsoil are layers of sand that sit on a plate of rock stretching for miles. Joseph Ndolo, principal geologist at the Ministry of Energy, explains that the sand layer can retain and filter dirt from water, while the bedrock keeps rainwater from seeping deeper into the ground.

“This is why there is heavy flooding in these parts of Kenya, because it takes time for the surface runoff to be absorbed,” he says. “Instead, most of the water washes away into seasonal rivers.”

The bedrock has long frustrated people who have tried to dig boreholes in search of water. A few meters from Kasomo dam, a hole 20 meters deep sits abandoned, its floor rippling with the motions of trapped snakes and other unlucky creatures.

“We kept digging through the rock but most of us gave up,” says villager Mwangangi, who helped build the Kasomo dam. “Caritas officials showed us how earth dams are an easier way to store water.”

To build a dam, community groups identify and donate a piece of land lying on the path of the surface runoff, explains Florence Ndeti, an official involved in the project at Caritas Kitui. Villagers then scoop out the topsoil to reveal the sand layer. The topsoil is used to create the walls of the dam, leaving only an inlet for rainwater, which soaks into the sand.

“When the rainwater is harvested, the villagers wait for about a day for the silt to settle," says Ndeti. "Then they can start using the water."


Friends of Kitui, a local community-based organisation, says there are about 33 such dams in the region. In a country where, according to the Kenya Bureau of Statistics, over half the population has to travel more than 15 kilometers to reach a reliable water source, the earth dams make access to water much quicker and easier.

But the hopes that earth dams could provide a widespread solution to Eastern Kenya's water troubles are up against a major problem: illegal sand harvesting by cartels in the construction sector.

According to Henry Wafula, a Lower Eastern Kenya administration officer, the sand is trafficked to the capital city to help feed Nairobi's housing boom. Investigations by his office indicate that brokers are paid millions of Kenya shillings for the sand, but those brokers often convince villagers to act as sand collectors and loaders for next to nothing.

“Most [villagers] cannot refuse the offer because they can use that little amount of money to buy food to last for a few days,” says Wafula. “But they are not aware of the damage they are causing to the ecosystem.”

The National Environment Management Agency (NEMA) blames sand harvesting for the declining water reserves in arid Kenya.

“When the sand is taken away, the water goes too,” says Boniface Mutinda, who represents the Eastern Kenya region at NEMA.

The effort to build more rainwater-harvesting dams faces other challenges as well.

Some in the community at Kasomo believe their earthen dam is a major step in the quest to achieve water security. But more of the villagers think a bigger, more reliable project that would give them access to groundwater and allow them to start irrigated agriculture would be a better bet.

Kagondu Njagi is an environmental writer based in Nairobi.

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