Nairobi's dwindling water supply causes alarm

When construction of the proposed Thika Dam, which is currently known as Ndakaini Dam, was mooted by the government in 1988, the end game was to have a reservoir to supply reliable water to the residents of Nairobi and its environs with minimum interruption.

Nairobi’s population has been steadily rising, from 4,000 in 1900 to 859,000 in 1979.

This was expected to further increase from 1.1 million in 1984 to two million in 1995 and reach a peak of 3.9 million in 2010.

Nairobi has always had piped water starting with the development of Kikuyu Springs and Kabete Treatment Works in 1906 with a capacity to supply 4,800 cubic metres daily.

This was followed by establishment of Ruiru Dam in 1936 and the Sasumua Dam on Chania River in 1945, which was expanded in 1956.

In the 1970s, these sources were no longer sufficient to meet the demands of the growing city during the dry season, and financing for a new and larger dam, Ndakaini, was proposed to alleviate water shortages.

HIGH DEMAND

In light of the ever-increasing water demand by city residents, which could not be solely met by the existing system, Ndakaini was thus meant to supplement the Chania River flows with a view to meeting the production capacity at Ng’ethu Water Treatment Plant.

Six years later, construction was complete with Sh2 billion injected into the project by the Kenya government, the World Bank, the African Development Bank and European Investment Bank, among other funders.

However, 25 years later, Nairobi residents are still grappling with shortages -- with rationing biting since January 2017. Some of the worst affected areas include Lang’ata, Umoja, Githurai 44 and Zimmerman estates.

Residents have been forced to dig deeper into their pockets to supplement the deficit by paying water vendors who have taken advantage of the situation to charge as high as Sh50 for a 20-litre jerrican.

County Water executive Vesca Kangogo says the rationing will continue until mid-next year, at the earliest, when it is set to reduce.

She says the deficit is not brought about by lack of water but an installed water treatment system capacity that can process only 525,600 cubic metres of water daily against a demand for 790,000 cubic metres.

The demand is also estimated to be increasing by about 20,000 cubic meters per year. In 2017, the demand was 760,000 cubic metres daily.

POOR INFRASTRUCTURE

Ms Kangogo points out that water received from sources must first be treated before it is released for use, and the county government cannot do anything until the system is expanded.

She said the current lines were initially set to serve the city up to the year 2000 but the government has not upgraded the infrastructure to meet the rising demand.

“The rationing is not because we do not have water but it is because of the installed production capacity that requires that we treat the water first before releasing it. There will always be that deficit because we cannot release water directly from the source to the pipes,” Ms Kangogo said.

The 4.397 million people who currently live in Nairobi, according to the 2019 census, require 790,000 cubic metres of water daily, but the supply is only 525,600 cubic metres daily. This leaves a deficit of 264,400 cubic metres of water.

Nairobi Water and Sewerage Company acting managing director Nahashon Muguna says water used in Nairobi County comes from Ndakaini, Sasumua and Ruiru dams, with capacities of 70 million, 15.91 million and 2.98 million cubic metres of water, respectively – and Kikuyu Springs.

This brings a total of at least 89.89 million cubic metres of water when all are full, as has been the case as from December 16, 2019.

RAINFALL

If this water can be treated to meet the 790,000 cubic metres daily demand, then the sources would supply Nairobi for nearly four months.

The short rains in Kenya occur between October and December while the long rains are received between March and May.

Rainfall is also received in January and February, especially in the Aberdares Range. The gap between the rainy seasons is not that big.

However, the bigger problem is the inadequate treatment capacity at Ng’ethu Plant, the largest urban water plant in East Africa.

The water plant was built in 1971 in three phases; the third phase being completed in 1997. It was designed to store 440,000 tons of water per day, accounting for 83 per cent of the total water supply in Nairobi.

In 2016, construction of the Sh4.7 billion Kigoro Water Treatment plant at Gatanga in Murang’a County began to help Ng’ethu in treating extra water flowing to Ndakaini Dam from the Northern Water Collector tunnel.

It was to be completed in May, 2018 but, as at March, 2017, only 15 per cent of the work had been done.

The plant, that was set to treat at least 140,000 cubic metres of water daily to boost supply of water in Nairobi and Murang’a, was only 35 per cent complete by July 2018 and reported to be 98 per cent complete in March this year.

FLOODING

In September 2018, Water Chief Administrative Secretary Winnie Guchu said the government will complete a new treatment plant to augment the Ng’ethu Treatment Plant and alleviate water problems in Nairobi County.

She added that a new pipeline to channel water to Nairobi was being put in place as there is a lot of demand for water in the city and the existing pipeline cannot handle additional water.

Nothing, so far, has come out of the two projects. This has perpetuated the irony of overflowing dams from heavy rainfall yet residents continue to suffer biting water shortages.

But the warning was explicit in the "Third Nairobi Water Supply Project Completion Report" of July 1998 by Africa Development Bank (AfDB), the parent project of Ndakaini Dam, which supplies about 84 per cent of water used in Nairobi.

“Along with the increase in water supply capacity, the design also addressed an increase in treatment, pumping, storage and distribution capacity to meet the demand to 2010.

However, the increase in treatment capacity would not be adequate for the 2010 demand, and additional treatment capacity would be required around 2005,” warned the report.

NEW WATER PLANT

The first Nairobi Water Supply Project was between 1972 and 1976 and the second (1978-84) developed the Chania-Kimakia-Thika river system to meet water supply needs of the city up to 1988.

The Ndakaini project – sitting on approximately 1,200 acres of land – was designed to serve Nairobi well into 2010; thereafter, additional investment would be needed to augment supplies, treatment and pumping capacity.

As designed, the construction of the dam should have increased the water supply capacity to 646,200 cubic meters daily, which would meet the demands to the year 2008.

Nonetheless, there might be some light at the end of the tunnel with the Northern Water Collector Tunnel project set to supply an additional 140,000 cubic metres when complete next year.

The ongoing construction of Karimeno and Ruiru dams is set to boost water supply by 50,000 cubic litres by 2021.