Harvesting water should be the norm, not exception, says expert

Harvesting as much water as possible is the surest way farmers can mitigate the effects of the changing climate, according to Erik Nielsen-Petersen a water engineer.

The managing director of Asal Consultants Limited, who has been consulting on water harvesting in Africa and Asia for more than 45 years, says harvesting water should start at the household level by tapping water from the roofs when it rains.

The water is then stored in containers and tanks for watering livestock and for domestic uses after undergoing basic treatment.

He notes that sprawling rock outcrops provide a suitable surface on which rainwater flows, and so are the rivers and streams in different areas.

He says sand dams and subsurface dams stand out among the sustainable methods of accessing water from river beds.

Whereas sand dams are growing in popularity among farming communities, Nielsen-Petersen has misgivings about them.

"It is not easy to site sand dams appropriately. They need to be located in an area that is a major source of coarse sand. This is because the sand is the best media for storing water in a sand dam. The coarser the sand accumulated in a sand dam, the more water the dam will hold,” he says.

Nielsen-Petersen's best bet in addressing drought is subsurface dams. He singles out a subsurface dam built through a partnership between Danida, which he worked for, and the Kenyan government in Kisasi in Kitui County 2005 as the best water project in his more than 45-year experience.

EMBRACE WATER HARVESTING

The expert does not advocate for sinking boreholes. "Boreholes are not sustainable. They are a source of saline water and their pumping systems collapse easily, making it costly to maintain them," says Nielsen-Petersen, 85, who came to Kenya in early 1970s, when one of the country's biggest concerns was trypanosomiasis.

The water engineer was to take part in a campaign to check the spread of the dreaded livestock disease, which entailed rolling out cattle dips in livestock production zones across the country in a project undertaken by Danish development agency, Danida.

“Midway through the cattle dip installation project, we hit a hurdle. Most of the areas we were working in were hit by severe drought, which made it hard for cattle dips to work properly,” he tells Seeds of Gold in an interview.

Then a light bulb moment hit Nielsen-Petersen. He set up a roof catchment and installed a sand dam at his rural homestead in Mukononi village in Makueni County. A shallow well which he sunk near the earth dam in 1976 is still the main source of water in the sleepy village.

According to Nielsen-Petersen, if farmers embrace water harvesting, they would produce food all-year round even as rains become erratic.

Makueni county Water executive Robert Kisyula says water harvesting should be institutionalised among farming communities.

“Multiple studies have shown that average households can survive on rainwater harvested and stored in two 10,000-litre water tanks throughout the year,” says Mr Kisyula, who served as the Malawi country director of World Vision.