Caption: Climate expert Lemi Muia (second left) talks with sand harvesters upstream of Maruba dam where he rooted for massive scooping of the commodity to create space for more water at the reservoir. Photo: Rose M/hivisasa.com
The perennial water shortage in Machakos town and its environs could be permanently eliminated if an innovative strategy is put in place to desilt the town’s main water source, Maruba dam, climate expert Lemi Muia has said.
For many years, Machakos residents have been forced to rely on water vendors for daily consumption, usually at an exorbitant cost.
At the same time, local water services provider, Machakos Water and Sewerage Company, whose water treatment works is located just a few meters downstream of Maruba dam axis has been forced to pump way below their capacity hence rationing of the commodity during the dry spells.
But a climate expert, Lemi Muia says the solution to water crisis in Machakos lies in implementing sustainable community-based interventions that could boost the reservoir’s water holding capacity to about four times the current level.
He says although water shortage in Machakos is with no doubt partly as a result of effects of climate change, there had been an element of lapses or lack of innovative strategy to mitigate the situation.
“The reservoir capacity of Maruba dam site has never been exhausted. The dam site has a potential backwash area of about 3 kilometers from the dam axis but this potential water storage natural wide valley is silted intensively,” says Lemi who teaches Geology at a local university.
According to Lemi, the siltation is so much so that a recent quick deposit quantification survey that was undertaken by university students pursuing Geology depicts a huge and massive sand deposits amounting to millions of tonnes.“If the sand is sold to the construction industry at the average cost per tonne in Nairobi, the county would make a cool extra revenue of upwards of approximately sh 20 billion,” says Lemi.Lemi says if the ready and high-quality sand is exploited, it will free up water storage space that will give the reservoir a storage capacity of about four times the current one or approximately 40 billion liters.“Desilting the dam using contractors may prove too costly to the county which is currently grappling with the menace of unsustainable wage bill,” he says adding that once the reservoir’s sand is scooped to the bedrock, county equipment should do the polishing and leveling of the new majestic water storage area.Another factor that was identified as untenable in the utilization of Maruba dam facility is use of the water to irrigate grass at the adjacent Machakos People’s Park and flower beds dotted along the Machakos-Nairobi highway.“There is an existing dam site, about four kilometers to the South of Maruba from whose stored water may be used to irrigate the public park’s grass and its beautification supplemented by high yielding boreholes,” he says.
The expert argues the second dam would be fed through an innovative Road Runoff Harvesting (RRH) program by using tarmac road in the nearby Machakos highway for tapping rain water.“Rain runoff water will be channeled to designer drainage systems along its stretch and directed to the dam via a super underground low-cost duct,” he says noting that the idea was becoming increasingly crucial in arid and semi-arid lands (ASAL).