Rainwater Harvesting: Killing Two Birds With One Stone
NAIROBI, – Bitter irony: in recent years Nairobi has experienced severe flooding and widespread water shortages, due to poor urban planning and collapsing infrastructure systems that are failing to support the Kenyan capital’s expanding population.
Shem Oirere Large parts of the city are not properly served by water and sanitation infrastructure, particularly crowded areas like the Eastlands estates of Umoja, Makongeni and Doholm but also wealthier enclaves such as Karen and Langata.
At the same time, the rapid expansion of the city has led to sealing off of large surface areas, increasing the speed and volume of storm water run-off. Furious flooding exposes and damages water pipelines and chokes drainage channels with debris, spilling raw sewage into the streets.
David Mburu, chair of the Kenya Rainwater Association, says because there is too much surface cover, rain water is prevented from percolating into the ground. Some city residents who have opted for boreholes as an alternative to the intermittent water supply are now experiencing inadequate yields.
Mburu says there is a need to encourage both the harvesting of rainwater from buildings and directing run-off water into system of drains that would recharge the groundwater levels.
“Not all this water should be harvested and stored since we also need to recharge our groundwater levels by encouraging use of construction material that allows for seeping of run-off water into the ground or leaving as much surface that allows infiltration of water as possible,” he says.
Peris Otachi, a resident of Kayole Estate, lost a brother in the 2001 floods, the worst experienced in Nairobi in recent years. “Flooding in Nairobi has become an annual ritual which unfortunately is never addressed by the city council or the government despite causing deaths and massive destruction.”
Eleven people were killed by floods in Nairobi in 2001; while police cannot confirm the exact numbers, at least 21 more people have been drowned in flood waters since then. Otachi, whose younger brother’s body was only found on the banks of the Nairobi River four days later, is now among residents who strongly believe that the floods can be controlled and the rainwater made better use of.
“It all starts with demystifying the rainwater harvesting technology,” says Mr Stephen Mutoro.”Let the people know it is within their reach to do it and its for their benefit in that they would reduce their water bills and access adequate water for non-potable use.” Mutoro is the Executive Secretary of the Kenya Water and Sanitation Network (KWSN), a water consumers’ lobby group based in Nairobi.
“We need to create methods to capture rainwater as surface water is inadequate to meet demand in congested, over-paved metropolitan cities,” says Professor Shaukat Abdulrazak, executive secretary of the National Council of Science and Technology.
A government statutory institute, the Council supports simple but effective rainwater harvesting methods as a solution to the over-paved city verandahs and streets. These include the installation of gutters to capture the roof water and setting up of underground storage tanks, especially by those putting up new homes and buildings.
How to get the process under way is a matter of some debate. Officials from the newly-created Nairobi Metropolitan Development (NMD) ministry, a new management structure for the greater Nairobi area, say rain water harvesting is to be enhanced to address the twin issue of flooding and water scarcity in the city of three million people, 75 percent of whom live in water-scarce slum and low income areas.
“We want to enhance effective rain water harvesting under an investment framework for water and sewerage services in the proposed metropolitan area in addition to managing metropolis’s water resource management capacity,” NMD minister Mutula Kilonzo promised during the launch of the draft on the proposed metropolis by President Kibaki in January 2008.
The minister said that the government would seek the enactment of a legal framework to regulate rainwater harvesting, but some stakeholders in the water sector have expressed reservations over proposals contained in the NMD’s establishing document, Nairobi Metro 2030, a 423 billion dollar blueprint on the future expansion and improvement of Nairobi city and its environs.
It’s not a question of denying the need for new regulations. Some existing legislation is an impediment to the implementation of the technology.
Mburu from the Rainwater Association points to current city bylaws as an example. “They have not incorporated rainwater harvesting and the existing infrastructure does not support the kind of technology we are talking about. But maybe within a given time frame the law may be changed for example to make it a requirement that all buildings provide for groundwater storage, gutters and roof storage.”
But the KWSN’s Mutoro says managing the problem of urban flooding in Kenya need not wait for a new legal framework, which experience has shown could take a long time. Instead, he urges campaigns to woo people to embrace the technology should be intensified.
“The government can make recommendations on the kind of roofing that is needed for every new house coming up in the city and give owners of the existing houses specified time within which they install rain water harvesting facilities but making it mandatory may not be the best way forward,” Mutoro suggests.
Let the city dwellers see the advantages of harvesting rainwater, he says “and when they compare the amount of money they are likely to save through using the stored rain water with that which they are paying the Nairobi Water and Sewerage Company for treated water every month there is no doubt they will embrace this technology.”
However, he says tax rebates on materials for setting up a rainwater harvesting system may be necessary when one considers the low income bracket water consumers.
Early in 2008, President Kibaki and former finance minister Amos Kimunya promised Kenyans the National Water Harvesting and Storage Policy Bill would be passed by Parliament before the end of the year.
But a crowded legislative agenda, dominated by debate and passage of crucial governance laws as recommended by two commissions appointed to investigate the bungled 2007 general election and post-election violence dragged on and by the time the legislators were breaking for their recess in December, the proposed Bill had not been tabled in Parliament. It is hoped that the new Bill would be brought to Parliament once the next session commences sometime in June.
Water and Irrigation assistant minister Mwangi Kiunjuri says the soonest the Bill can be brought to Parliament is August 2009.
“Parliament has proceeded on recess and the parliamentary year is over. And when we come back we will embark on budget debate, so the earliest it may come is August or thereafter,” Kiunjuri said.
Until new systems are put in place, the city will be suffering unnecessarily. The United Nations Environmental Programme (UNEP) estimates that Nairobi has a potential to harvest almost ten million cubic meters of water each year, if rainwater harvesting measures were in place in all the city’s rooftops, roads, open grounds and forest-covered areas.
A survey report by UNEP, “Potential for Rain Water Harvesting in Ten African Cities”, shows that Kenya’s capital has the potential to supply the water needs of between six and 10 million people “with 60 litres a day if rainwater were efficiently and effectively harvested.”
“The rainfall contribution is more than adequate to meet the needs of the current population several times over and Kenya for example, would not be categorized as a ‘water stressed country’ if rainwater harvesting is considered,” the UNEP survey report adds.
No time to lose.
Credit: Shem Oirere