More than half the world’s eight billion people will be living in cities within five years, demographers predict – and Africa is at the forefront of that transition.

The west African nation of Cameroon has been leading the trend. By 2010, the majority of its people already were living in urban areas, putting pressure on infrastructure and city services.

The capital, Yaoundé, exemplifies the challenges – swelling, crowded communities where schools, clinics, jobs, sanitation and access to clean water are scarce. Urban agriculture is practiced across the city, and humans share space with an estimated 50,000 pigs and over a million chickens, according to the UN Food and Agricultural Organization (FAO).

Particularly troubling to public health officials was the lack of systems for handling waste water. Sewage, combined with torrential rains, regularly overwhelmed the four tributaries of the Mafoundi River and 34 streams that crisscross the city and drain the area, flooding neighborhoods with bacteria-laden effluence and causing high rates of water-borne diseases. Latrines also overflowed, contaminating drinking-water wells.

“In Yaoundé, analysis of irrigation water revealed levels of faecal bacteria and parasites that were a health risk to both growers and consumers,” said an FAO report. The Rome-based agency said samples of agricultural produce grown around town showed both chemical and microbiological contamination. Heavy clay soils contributed to run-off problems and intensified flooding.

Severe floods disrupted the city 15 to 20 times a year, affecting as many as 100,000 people at a time. Rampaging water damaged or destroyed houses and businesses and polluted the capital’s water treatment plant.

In recent years, storms became stronger and more destructive as a changing climate altered weather patterns. Scientists point to greater rainfall variability and greater frequency of heavy rains, alternating with periods of drought.

National and local officials decided something had to be done. With the help of the African Development Bank (AfDB), planners studied the problem and developed the Yaoundé City Sanitation Master Plan. The first phase, over was a U.S.$38 million project for cleaning drainage ditches, installing canals to handle larger amounts of waste water and improve the quality of water sources.

The Bank contributed funds to launch the initiative, along with the government of Cameroon.

Flooding is also a national problem. In August the country’s main commercial city, Douala, on the Atlantic coast was partially submerged after weeks of heavy rains swept through homes, markets and the business centre. During September and October, flooding progressed upriver, past Yaoundé to Cameroon’s far north, an area more commonly plagued by drought.

Minister of State for Property and Land Tenure Jacqueline Koung Bessike promised that emergency projects to build low-cost housing to relocate flood victims, to replace latrines and to protect water points will be underway by next month.

Meanwhile, the initial Yaoundé flood-mitigation scheme, according to an evaluation by the AfDB last year, succeeded in reducing the frequency of floods from more than 15 per year in the capital to three, over four years.

The Bank’s analysis linked the improved water and sanitation controls to a substantial reduction in water-borne diseases, including malaria – down 47 percent, typhoid – down 47 per cent, and diarrhea – down 36 per cent.

Three years ago, Yaoundé joined a campaign by the United Nations Office of Disaster Risk Reduction, aimed at making cities more resilient, after Yaoundé's dynamic, popular mayor, Jean Claude Adjessa Melingui, participated in a debate on urban risk reduction in Nairobi, Kenya. Adjessa Melingui died last year at the age of 50, but city officials vowed to continue his plans to transform the capital and reduce poverty.

As part of that campaign, Yaounde is building on the success of the initial flood-reduction efforts. It has begun to implement a $152 million plan, largely financed by loans, primarily from AfDB and the French development agency.

By its scheduled completion in December 2017, the project will directly benefit 1.8 million people – three-quarters of the capital’s population – if it meets its targets.

In addition to enhancing the sanitation infrastructure, the associated public works projects are expected to create jobs, both through hiring laborers from local neighborhoods and by engaging small and medium-sized businesses in sub-contracting and consulting. Seven district governance councils and local non-governmental organizations will be involved, according to the plan.

Taking into account predictions for increasingly variable weather patterns, the project has built in “resilience and adaption” measures to monitor water level changes in the area. The city is procuring hydrological monitoring gauges, software and computers and is training workers in GIS (geographic information system) data management.

Eliminating areas where storm water tends to stagnate is expected to further “reduce the proliferation of mosquitoes that spread malaria (the leading cause of mortality in countries south of the Sahara),” says the AfDB, which also expects the prevalence of water-borne diseases to continue to fall. “Children under the age of 5, who are the most vulnerable segment and most affected by these diseases, will be the main beneficiaries,” it says.

Another aspect of the Yaoundé Master Plan is to develop green spaces, parks, and plots to grow flowers alongside the new, concrete rainwater canals. “The project will also contribute to the creation of jobs for young people in the disadvantaged neighbourhoods bordering the canal,” the Bank says. “To this end, using the labour-intensive approach in the canal works and related developments will create almost 2,500 jobs.”

Remarkably, the city says that only three households will have to be moved, due to waterway improvements and green-space development. It promises that the City Council will pay compensation to those affected.

Yaoundé officials say that at least 300 women will be hired to do “sensitization” public education, aimed at changing behaviors that treated waterways as trash disposal receptacles. Plans call for the building of women’s and youth centres to promote income-generating activities and recreation.

Education and training is also extended to Cameroon’s media professionals. In August, the country’s commercial hub, the city of Douala on the Atlantic coast, hosted a three-day regional workshop organized by the Global Water Partnership.

Reporter George Mbella of the Cameroon Tribune said journalists heard “that if they do not broadcast enough information to help communities adapt to the effects of climate change then the latter's nefarious effects will be disastrous in all domains of human life”.

Mbella said a workshop lecturer told the 30 journalists: “The greatest threat of climate change is on water resources.” The effects of floods, as well as of periodic water scarcity, caused by extreme weather, contributes to “increased malnutrition, food insecurity, poor water quality and the promotion of illnesses such as typhoid, cholera, meningitis and malaria,” the journalists were told.

The Cameroon government says it is working aggressively to become a middle income country and to meet UN-sponsored Millennium Development Goals for reducing poverty and saving lives by 2015.

Yaounde’s response to climate shocks and raging rivers, which city officials hope will demonstrate what can be accomplished through integrated planning, could help propel the country towards those goals.