December 18th 2017

Top Stories / National

Millions of Nairobians could be drinking ‘poisoned’ water

A recent assessment revealed a doubling number of ‘known’ boreholes between 1995 and 2011. Of 3,500 boreholes, less than half have abstraction permits (47 %) and two thirds were unmetered.

By Oscar NdundaSaturday, 01 Oct 2016 19:35 EAT

A new borehole development.

The government has sounded a warning over the uncontrolled construction of boreholes in Nairobi which is life threatening to the residents. The city currently has more than 6,000 boreholes, out of which only 2,000 have been approved by the authorities.

Some property developers drill water in polluted areas around Industrial Area, Eastlands and off Mombasa Road in areas like Athi River. Unsuspecting residents of the city consume this commodity unaware of the dangers it poses.

The Water Resource Management Authority (WRMA) which is the lead agency in the management and regulation of water usage, has its database showing that only 2,000 boreholes have got approvals that ascertained their technical, health, environmental and security standards.

According to Eng. Boniface Mwaniki, the technical manager at WRMA, the vast majority of boreholes have been put up by unscrupulous engineers. The authority therefore cannot vouch for the quality of water being consumed by tenants of residential estates whose landlords have sunk illegal boreholes.

While many Kenyans believe that groundwater is inherently clean, experts warn that contaminated surface water seeps deep into the soil in extensively polluted areas thereby endangering those who consume such ground water.

Surface and groundwater are connected through what scientists call aquifer regeneration, where surface run off seeps into the ground during floods. Excessive pumping of groundwater to support population growth quickens the lowering of the water-table and losses of riparian ecosystems since groundwater contributes to the moisture in the atmosphere, which supports vegetation.

The immediate cause of overproduction of groundwater is the limited supply of piped water in Nairobi. The Nairobi Water company, the monopoly owned by the county government, supplies water to slightly over half of Nairobi’s population.

Those Nairobians not supplied with piped water rely on borehole water. During drought or periods of erratic supply, even some homes with Nairobi Water connections switch to borehole water. Nairobi Water has also drilled boreholes to increase its water supply, the vast amount of which is tapped from dams in Muranga County.

Borehole drilling requires various health and environmental standards assessment set out in the Water Act 2002 and regulations under the Act. Many landlords, however, ignore these regulations, putting the health of consumers of the water in their properties at risk. The uncontrolled drilling of boreholes also put the stability of the soil at risk.

If Kenya maintains a “business-as-usual” approach in managing its water resources, by the year 2030, there will be a 30 percent gap between water demand and practically available supply. In many areas, local water stress is already presenting social, environmental and economic challenges, not only in the large arid areas of the country but also in more developed regions where water-intensive economic activity has grown rapidly, such as Nairobi.

The stability of the earth is anchored on a balance between surface and groundwater. If the latter is depleted, heavily built areas like Nairobi could submerge over time. The depletion in groundwater in Nairobi follows a pattern of environmental destruction that has affected water catchment areas and previously forested areas like west of Nairobi and in such estates as Karen, Runda and Nairobi North.

With the rapid construction of real estate, sports facilities in such areas as Karen, Runda, Kitengela and northern areas like Ruiru, it is not only that water catchments have been destroyed, vegetation is also fast disappearing as most of the land is covered by impermeable surfaces like buildings, roads and sports facilities.

Matters are made worse by the poor drainage system in the city that does not allow quick surface flow. Inefficient surface-water runoff during the rainy seasons causes trouble because much less water percolates into the ground.

Despite the destruction, water supply in Nairobi is 20 percent lower than required and by 2035 is expected to be more than 60 percent lower than projected demand. With industrial demand predicted to increase by 125 percent between 2014 and 2030, addressing the challenges of unreliable and decreasing water supply, in addition to flooding, pollution and catchment degradation will be vital to ensure the continued and sustainable industrial growth in Nairobi and other industrial centers.

Nearly 98 percent of available freshwater in Nairobi is stored in underground aquifers and Nairobi’s water management success will be largely based on preserving such resources. A recent assessment of boreholes in the Nairobi Metropolitan Area revealed a doubling number of ‘known’ boreholes between 1995 and 2011. Of 3,500 boreholes, less than half have abstraction permits (47 %) and two thirds were unmetered.

Groundwater depletion can lead to what economists call the tragedy of the commons, a problem whereby every individual tries to reap the greatest benefit from a given resource whose demand is higher than the supply, and every individual who consumes an additional unit directly harms others who can no longer enjoy the benefits.

The writer is the news editor of the Kenya Free Press

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