Floods, Respiratory Diseases in the Absence of Urban Forests in Kigali

Vianney Ntakiyimana—a shop owner trading electronic equipment at Rwanda’s largest bus terminal, the Nyabugogo bus terminal between Nyarugenge and Gasabo districts in Kigali—recalls losing nearly Rwf1 million ($707 USD) in a single day due to flooding.

The bus terminal connects the city to various regions of the country, serving as a one-stop centre of transportation.

“Flooding damaged all my goods, and I had to dispose of them. They included phones, phone chargers, phone covers, and other merchandise,” he recounted.

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Ntakiyimana, who has been in business for 10 years, has frequently experienced flooding in the area.

“Before the Mpazi drainage system was expanded, the bus terminal would often be submerged, causing extensive damage to goods as the drainage system would overflow. To protect my shop, I even built a cement barrier in front of the door to block floodwaters,” he explained.

According to Ntakiyimana, the runoff water causing the flooding originates from the surrounding hills.

The problem is exacerbated by the lack of rainwater harvesting and retention measures.

Forests that once mitigated flooding have been encroached upon, with houses built in their place, leaving residents in high-risk zones.

“I remember we spent an entire week cleaning the shops and trying to salvage the few items that hadn’t been damaged by the floodwaters. Unplanned settlements have significantly contributed to the recurring flooding,” said Jean Baptiste Kigenza, who deals in beverages, food, and hygiene products. He lost over Rwf50 million ($35,350 USD) in a single day in 2020.

The floods swept away food, beverages, fridges, laptops, his car, and other valuable property.

Aaron Musabyimana, a cyclist who transports goods across the Nyabugogo River bridge, added: “Flooding was much worse before the bridge was widened. Some passengers even lost their lives, and others were swept away by the river’s waters. ... Cyclists could not generate any income.”

The business community mentioned areas such as Nyamirambo, Kimisagara, and Gatsata as the origins of the flooding. These areas are home to three forested hills in Kigali: Mount Jali in Gasabo District, Mount Kigali in Nyarugenge District, and Mount Rebero.

The degradation of the hilly terrains of Mounts Kigali, Jali, and Rebero has significantly heightened the risk of erosion and severe flooding downstream, particularly in the Nyabugogo, Gatsata, and Nyabarongo valley areas, according to Abias Maniragaba, an environmental economics lecturer at the University of Lay Adventists of Kigali (UNILAK).

“Whenever a house was elected it meant a number of trees were cut on such hills. People were told to relocate from Gatsata, for instance, because settlement in the surrounding hill has created high-risk zones ... runoff water from the houses has caused flooding, causing damages and claiming lives of people. Planting trees is one of the solutions,” he said.

In 2020, police and local authorities in Nyarugenge District urged communities living around Mount Kigali Forest to report people involved in deforestation activities. At that time, several people were caught cutting down trees in the protected forest.

In 2015, the Institute of Policy Analysis (IPAR), an independent, not-for-profit research and policy analysis think tank in Rwanda, warned that businesses around Nyabugogo River, Gatsata, and other water catchment areas in Kigali could face further losses due to flooding if no urgent actions are taken to address the problem.

IPAR’s survey on how small businesses in Kigali are being affected by recurrent flooding, indicated that small businesses in the areas experience losses estimated at Rwf178.2 million ($125,987 USD) annually in damages caused by floods.

Most of the more than 360 respondents in the survey were dealers in car spare parts, general merchandise, or food.

The survey showed that 75 per cent of the business premises could not be accessed by customers, while 38 per cent lacked access to electricity, among other things.

More than 80 per cent of the respondents said the flooding experienced in 2013 was the worst in the last three years. Eighty-one per cent of businesses were affected by floods in 2013 and 2014.

The annual damage costs made up 22 percent of the total net profit of the businesses in the area.

The survey also showed that 71 per cent of 355 businesses took measures to protect their properties against flooding, including using flood barriers, moving production inputs higher above the ground, creating ditches around the buildings, and using waterproof building materials. In the survey, 28 per cent of businesses said the measures needed to curtail the effects of flooding were too expensive or there was little information about them.

Cost of flood management

Kigali expanded the Mpazi drainage, which passes near the Nyabugogo bus terminal and also expanded two bridges on the drainage that flows into Nyabugogo River at the cost of Rwf7.7 billion ($5,397,700 USD).

“Think back to the flooding that once plagued Nyabugogo; the new bridges have effectively addressed those problems. Thanks to the improved drainage systems, we have significantly reduced the dangers and risks to citizens’ lives, as floods caused by natural disasters previously claimed lives,” stated Samuel Dusengiyumva, the mayor of Kigali.

Kigali explained that the rise in the cost of building two bridges over the Mpazi channel—from Rwf2 billion to Rwf7.7 billion ($1,402,000-$5,397,700 USD)—to address flooding in Nyabugogo’s commercial area was caused by unusually high rainwater levels, a consequence of climate change.

The water discharge into the drain increased by about 70 per cent, to 110 cubic metres per second from 65 cubic metres.

The Nyabugogo bus terminal is set to be revamped, with larger capacity and better resilience to flooding by 2027. The city has spent Rwf2 billion to rehouse families who were being affected by Mpazi drainage flooding.

The city also faces flooding in 15 other places—including Rwandex, Rugunga, Gikondo, Kinamba, Nyabugogo, and Nyamirambo—and areas in different districts. Plans are underway to install flood sensors and build bridges as well as culverts.

The city seeks to construct 66 drainages to manage flooding from hills and unplanned settlements.

The city has invested over Rwf1 billion ($701,000 USD) to develop the Kigali Stormwater Management Master Plan, which is expected to be completed soon to mitigate floods in the capital.

“Nyabugogo frequently experiences flooding and erosion due to landowners cutting down trees to build houses and paving their compounds instead of planting trees or creating gardens. This accelerates runoff water, leading to significant damage,” observed Athanase Mukurarinda, an environment expert.

Effects of urban deforestation on public health

Experts have said urban forests impact health.

“This implies that illnesses aggravated by (the) absence of urban forests, such as asthma ..., will increase,” Mukurarinda added.

Dr. Emmanuel Sibomana, the director in charge of communicable respiratory diseases, tuberculosis, and other respiratory diseases at Rwanda Biomedical Centre, said there is not yet intensive research to know the number of cases of respiratory diseases caused by deforestation in Rwanda.

However, he noted that there is a hypothesis that deforestation reduces the quality of air, leading to an increase in respiratory diseases.

“It requires intensive research to determine these specific data on respiratory diseases caused by deforestation. However, in general, in 2023, at least 471,171 cases in Kigali were treated (for) signs of respiratory diseases. These cases make 9 per cent of all cases recorded in the whole country in that year,” he said.

Sibomana said that in 2022, health centres across the country received 11,501,888 patients, of whom 38 per cent had respiratory disease.

“It is true that urban forests have decreased in Kigali due to settlement, housing, and other infrastructure projects, since air quality has decreased in our observation,” he said.

From 2012 to 2015, hospital admissions increased from approximately 1,682,321 in 2012 to 3,331,300, of which 13 per cent is linked to air pollution.

In Rwanda in 2012, more than 2,200 respiratory-related deaths occurred, of which 22 per cent of deaths were children under 5 years old. The estimated number of deaths from all types of air pollution in Rwanda in 2019 was 9,286.

“The numbers keep increasing and reforestation is one of (the) solutions to help improve air quality,” he noted.

Today, 90 per cent of people globally breathe polluted air and approximately 7 million people die from air pollution-related causes every year.

Air pollution costs the global economy $5 trillion in welfare costs annually and ground-level ozone pollution is expected to reduce staple crop yields by 26 per cent by 2030.

Rwanda, in 2023-2024, spent $7.52 million on tuberculosis and other respiratory communicable diseases, according to the Rwanda Biomedical Centre. Rwanda has developed an Air Quality Monitoring System, which provides data on the quality of the air at 23 sites across Rwanda.

The system provides a real-time Air Quality Index (AQI) for each station in both numerical and colour-code format. It also highlights the dominant air pollutant that is responsible for air quality degradation during the reported period for each station.

In July 2024, the Rwanda Environment Management Authority warned that sensitive groups—which include the elderly and people with pre-existing conditions such as diabetes, heart disease, and lung disease—are at risk as ongoing dry spells are exacerbating poor air quality.

“We have a huge task to improve air quality in (the) City of Kigali. The air has been losing quality,” said Kigali Mayor Dusengiyumva, who added that interventions also include planting 3 million trees as part of nature-based solutions to manage stormwater and improve air quality.

They include planting trees and vegetation on hills, along rivers, and drainages to help reduce the speed of runoff water to avoid flooding.

The city is also rehabilitating and conserving wetlands because they retain and curb floods in addition to improving air quality.

Currently, five wetlands are under rehabilitation on 500 hectares after the successful establishment of the Nyandungu eco-tourism park.

It is also preparing to create the Kinyinya Forest Eco Park on the former Deutsche Welle Radio site.