"As the developing world witnesses a boom in road building, a movement to retrofit existing roads is gathering steam. Using embankments, channels, and dikes, so-called “green roads” help control floods, harvest excess water for use in irrigation, and slash maintenance costs."
"Makueni County, a corner of southern Kenya that’s home to nearly a million people, is a land of extremes. Nine months a year, Makueni is a hardened, sun-scorched place where crops struggle and plumes of orange dust billow from dirt roads. Twice yearly, though, the county is battered by weeks of torrential rain, which drown farm fields and transform roads into impassable morasses. “Water,” says Michael Maluki, a Makueni County engineer, “is the enemy of roads.”
Maluki’s axiom is true the world over: Where roads and water intersect, trouble follows. Roads cut off streams and bleed sediment; meanwhile, floods often erode roadbeds into muddy gullies. Although wealthy nations are far from immune, these problems are most severe in developing countries, where roads are largely unpaved and thus especially vulnerable to obliteration. In Kenya and other nations, the issue is exacerbated by climate change, which has amplified the intensity of seasonal monsoons and droughts.
In 2019, Maluki began to ponder how to reconcile two of his county’s challenges: the aridity of its dry season and the destructiveness of its wet season. That year, he and colleagues attended a local workshop led by a Dutch consulting firm called MetaMeta on the concept of “Green Roads for Water” — a set of precepts for designing roads to capture water through strategic channels, culverts, and ponds and divert it for agricultural use. Inspired by the session, Maluki brought the idea to his colleagues and local farmers, who gave Green Roads their cautious blessing."
Ben Goldfarb reports for Yale Environment 360 December 14, 2023.
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