A Flood-Plagued African City Sets Out to Reengineer Its Wetlands |
Flooding in Kigali in January 2020. Emmanuel Kwizera/Wikimedia
This story was originally published by Yale e360 and is reproduced here as part of the Climate Desk collaboration.
Maurice Manishimwe runs a small garage beside a fuel station in Musango village, just outside the Rwandan capital of Kigali, in a nation known as the land of a thousand hills. Sandwiched between one of those hills and the Nyabugogo River, his workshop hums with activity as people arrive with cars and equipment to be tested and repaired.
But this busy location comes at a cost: When rainstorms hit, water running off the hillsides and rising river levels flood the streets and spill into Manishimwe’s workplace. “Our shops were submerged and our goods were destroyed,” says the 30-year-old, speaking about a December 2023 storm that surrounded his garage with knee-high water. He says the flood cost him thousands of dollars in lost inventory and tools.
Manishimwe built a higher step into his workshop to protect his brake pads and taillights, laid new tiles, and replaced his wooden shelves. Still, he worries that heavy rains could once again wreck his shop.
“The project represents a rare, citywide effort to rebuild nature-based infrastructure.
Kigali, a city of 1.7 million, has historically seen an average of nearly 40 inches of rain a year. But rainy seasons in Rwanda are becoming both “shorter and more intense,” according to the Rwanda Environment Management Authority (REMA). Since 2017, East Africa’s spring rains have shown record-breaking extremes as warmer air and ocean surfaces load storms with more moisture.
Forty years ago, Kigali was protected from stormwaters by extensive wetlands at the base of its many hills. The wetlands soaked up rain, slowed floods, and filtered runoff. But decades of degradation, including informal agriculture, sand mining, and industrial dumping in these areas have reduced the wetlands’ ability to perform these essential ecological functions.
Rapid urban growth has placed additional pressure on the wetlands. The city’s population has risen by 4 percent each year since 2020, and open space continues to be replaced with impermeable concrete, which sends ever more runoff downhill. The flooding erodes soil, destroys buildings and infrastructure, and causes tens of millions of dollars’ worth of damage a year, according to Teddy Kaberuka, a Rwandan economist.
Eager to protect its citizens and property, create green space for communities and wildlife, and curb financial losses, Kigali began working nearly a decade ago to restore its natural defenses. In just a three-year period, the city converted a degraded swamp into a functioning wetland—featuring a series of ponds, a riverine forest, and a savanna—that stores carbon, controls floods, filters pollutants, and enhances biodiversity. Building on that success, the city is now reforesting hillsides and restoring an integrated wetland system that will eventually span........