A “superhero” moss can significantly reduce the risk and severity of flooding for communities living in downstream areas, the researchers found.
Scientists from the conservation group Moors for the Future Partnership, who conducted a six-year study of sphagnum moss, found that planting it high up could dramatically slow the rate at which water runs down hillsides, preventing watersheds from rivers flood with water downstream.
The research found that sphagnum moss reduced peak stream flow, the maximum amount of water that enters a river after a storm, by 65%. Moss was also found to increase lag time (the time between rainfall and rainwater entering the river system) by 680%.
More than 50,000 individual sphagnum plants, which are about the size of a 50p coin, were planted at Kinder Scout, the highest point in the Peak District National Park, as part of an ‘outdoor laboratory’ for researchers observe them.
Before the moss was planted in Kinder, the surface of the hill consisted of bare peat, which meant that after a storm, rainwater washed directly away, leaving communities in the downstream valleys more vulnerable to storm surges. floods.
Therefore, the planting of sphagnum moss could bring important ecological benefits. The plant is capable of absorbing up to 20 times its own weight in water, which means more rainwater can be retained upstream and enter the river basin more gradually to prevent overflow. Sphagnum moss can also help protect the peat layers below it and can build up over time to create new peat layers that are essential for carbon storage.
The researchers say the benefits of planting sphagnum moss will amplify over time as the plant grows, and that moss planting has the potential to deliver global benefits in terms of climate, water quality and flood severity.
Tom Spencer, a research and monitoring officer with the Moors for the Future Partnership, said the results were “striking” and praised the dramatic effects the moss has had on the river basin.
He said planting sphagnum could be “a powerful tool to minimize the risk and severity of flooding”, which would have “far-reaching benefits for downstream communities”.
Helen Noble, executive director of the South Pennines Park, echoed that sentiment, saying the findings “are fantastic news for communities that are most vulnerable to flooding in the South Pennines.”