Desilt dam to end water crisis, says expert

Lemi Muia (left), a climate expert, speaks to sand harvesters at Maruba Dam in Machakos County. [Photo: Erastus Mulwa/Standard]

Water shortage in Machakos town and its environs could be a thing of the past if silt is removed from a local dam.

Residents have been forced to rely on vendors who have been minting money from them by selling them the commodity at exorbitant prices.

The problem has been further compounded by the fact that the treatment plant of the local provider, Machakos Water and Sewerage Company, has been pumping water below its capacity. This has led to serious rationing of water, especially during dry spells.

However, a climate expert, Lemi Muia, who teaches geology at a local university, says the capacity of Maruba Dam will go up to about 40 billion litres from the current ten if all the silt is removed.

"The solution to the water crisis in the town lies in implementing interventions to boost the reservoir's water holding capacity to about four time and this should involve the community," Muia said yesterday.

He said water shortage in the town is not entirely as a result of climate change. "There has been an element of lapses or lack of a strategy to deal with siltation.

"The capacity of Maruba Dam has not been exhausted. The dam has the potential backwash area of three kilometres. However, this space has been eaten up by silt," says Muia.

He said a recent survey by university students revealed massive sand deposits that if harvested, can be sold for billions of shillings.

Muia said the dam has millions of tonnes of sand. "If the sand is sold to those constructing houses at the average cost per tonne, the county can make a cool Sh20 billion in extra revenue," says Muia.

"If the ready and high quality sand is exploited, it will free up water storage space that will see the reservoir's capacity go up about four times."

Meanwhile, to ease the water shortage further, the expert urged the county government to consider employing what he referred to as Road Runoff Harvesting (RRH) programme which will see tarmacked road used to tap rain water which will later be treated and used even for domestic purposes.

"Surface runoff will be channelled to designed drainage systems along the road and directed to the dam via a super underground low-cost duct. This idea is becoming increasingly crucial in arid and semi-arid lands."

"If supplemented by boreholes, it'll ensure the town and its environs have water at all times," Muia said.

Muia termed using water from Maruba Dam to irrigate grass at the nearby Machakos People's Park and flower beds along the Machakos-Nairobi highway a wrong idea because the dam does not have enough water.