Rainwater harvesting key to alleviating water shortage

By LILLIAN ALUANGA-DELVAUX

The coming weeks are expected to see a reduction in the amount of rainfall that has pounded the country, leaving a trail of death and destruction.

According to the latest predictions by the Meteorology Department, the current rains are expected to end this month in most parts of the country, but continue into June for Western and parts of Rift Valley provinces. But even as the nation counts the losses incurred by weeks of flooding, there is a likelihood that much of the water, which could otherwise be harvested for use in dry seasons, may have gone to waste.

But not so for a housing complex in Nairobi’s Karen area. While much of the country may be ruing the lost opportunity, Sanjiv Seedhar will have little to worry about keeping the 28-acre piece of land, on which stand 28 housing units, lush.

What was an idea borrowed from a farm in Yatta, Machakos District, has resulted in well-manicured gardens purely sustained by water harvested from rains.

At the centre of the group of waterfront homes is a stretch of about two acres of land on which sit three man-made lakes that water harvested from gutters fitted onto the roofs drains into.

The lakes, which are about 1.2 metres deep, are currently at full capacity and lie below picturesque wooden bridges linking homes across the water.

While water levels in the lakes may drop to about six inches in the dry season there is currently enough to last the gardens for several months. At the Sandalwood Properties, aesthetics and conservation techniques have been meshed into what may be considered a model on rainwater harvesting for other housing complexes within the city.

Planning weakness

While the roofs are designed in a way that allows for easy flow of water, there are drains strategically fitted at different points to ensure water flowing from the gutters and runoff from nearby roads drains into the lake.

Then there are automatic sprinklers fitted into the ground to ensure the gardens are well watered, and a small sewer treatment plant on the facility to ensure a steady supply of water to the gardens — regardless of the season.

“We are hoping to get more property developers to think this way, not just about water conservation, but incorporating other energy saving techniques such as the use of solar panels,” says Mr Seedhar.

Although some people might have reservations to its use, sewer water, when treated, can be used for various domestic purposes, as is the case for the Karen project where it is treated and used for gardening.

While admitting the technology that accompanies rainwater harvesting is not cheap, Seedhar says its long-term benefits outweigh initial costs, and is worth tapping into for a nation still struggling to sufficiently meet her water needs.

Roofing material

“It (rainwater harvesting) must be incorporated from the design stage of our buildings. It doesn’t have to be at the level we are doing it here but each home could replicate this in a small way,” says Seedhar.

He says subsidies by Government on roofing material, water tanks and other tools used in setting up rainwater harvesting mechanisms would go a long way in encouraging more homes and institutions to embrace the technology.

University of Nairobi lecturer Eric Odada says poor planning is to blame for the wastage of water experienced during rainy seasons.

“Kenya is a unique country where we have people dying both from the effects of drought and flooding in a span of six months. This is not an environmental issue but a weakness in planning,” he says.

According to Prof Odada, a lecturer in the Geology department, the current rainwater could sustain the country through the next two to three seasons, if harvested and stored well.

He says communities in their own way undertook to harvest rainwater, which was often stored in dams or huge water pans. The use of such water was restricted to dry seasons, hence sustaining water needs when there was little or no rainfall.

“In the same way, we can build small dams to control flood waters and capture the water which can then be stored for future use,” says the lecturer.

Odada says while the concept of water harvesting is yet to be fully exploited in the country there is little infrastructure to allow the ease of installing such technology.

“Why can’t the Government and other relevant authorities make it mandatory for anyone putting up a building to have built -in water storage facilities,” he poses.

Odada cites Israel, Egypt, India and China, as among countries that have successfully adopted rainwater harvesting to meet their water needs.

“In Egypt, for instance, most water used in homes is tapped from the rains given that the River Nile is about the only major source of water for the country,” he says.

In such cases water is often stored underground in dams and small rooftop tanks from where it flows into the houses for domestic use.

Asbestos dangerous

Odada however cautions on the need to treat rainwater before consumption. Some areas are very dusty and as such the water harvested from the roofs may not be very clean,” he says.

City Planning director Tom Odongo agrees and points to untreated water harvested from asbestos roofs as dangerous for human consumption.

While there may be little to show for the council’s efforts in rainwater harvesting, Odongo says studies are currently being conducted on the management of storm water among systems currently used by developed countries.

“We are reviewing regulations dealing with water harvesting but its not just water we are looking at, but how we can sustainably meet other energy needs,” he says.

Odongo says while the council’s public health and sanitation department would not allow use of harvested rainwater for consumption before its treated, it does not necessarily bar people from using the water for other purposes.

Like Egypt

Jackson Raini  of Flamingo Net, a conservation organisation, proposes a deliberate push by the Government to have all schools and health institutions particularly in the rural areas to invest in rainwater harvesting technology.

“We have problems with sanitation in these institutions because they have no water but this is a problem that can easily be solved by harvesting the rainwater, which can then be used for flushing toilets and washing hands,” he says.

But he, too, admits that the costs of adopting rainwater-harvesting methods may not be cheap for the average household.

“Buying a 20,000 litre capacity tank could cost one about Sh80,000, while setting up a small capacity water pan measuring about five metres by five metres would cost at least Sh30,000. Despite the costs, however, many rural homes in Nakuru are digging water pans to store water for gardening, livestock and cleaning purposes.