In 2017, the upper Afon Cothi in Carmarthenshire was barely recognisable as a river. Decades of agricultural drainage works had straightened the channel, stripped its banks of vegetation, and removed the gravel beds where salmon and sea trout had once spawned. The river ran fast and shallow in wet weather and dwindled to a trickle in summer. Invertebrate surveys showed a community dominated by pollution-tolerant species. There were no otters.
That year, Alder & Otter began a restoration programme in partnership with the Afon Cothi Landowners Group and Natural Resources Wales. The first phase involved remeandering 4.2 kilometres of the main channel — cutting new bends to slow the water, trap sediment, and create the varied depths and flows that freshwater species need. Riparian buffer strips were planted on both banks, fenced to exclude livestock. Willow, alder, and hawthorn went in over three seasons.
The ecological monitoring began before a single spade went in. Our science team, led by Priya Nair, established baseline transects for invertebrates, vegetation, and fish at twelve points along the catchment. Those same points have been surveyed every autumn since.
By 2021, the invertebrate data was showing what the team had hoped for: a measurable shift from pollution-tolerant to pollution-sensitive species, including the reappearance of stonefly larvae — an indicator of clean, well-oxygenated water — at three of the twelve sites. Juvenile salmon were recorded spawning in the new gravel beds the following spring for the first time in at least twenty years, based on local memory and historical records.
In the autumn of 2023, one of our Wildlife Guardians volunteers found otter spraints at seven survey points on the restored stretch. By the end of 2024, camera traps had confirmed a breeding female and at least two cubs.
Seven years on, the Afon Cothi is not finished. The lower catchment remains degraded and there are ongoing pressures from slurry runoff in the headwaters. But the 4.2 kilometres we restored are functioning as a river again. The invertebrates know it. The salmon know it. The otters know it.