Small puddles, big job

These unassuming pools on the northeast shore of Lake Hayes are quietly doing some of the most important work in our whole catchment. Stormwater running off the hillside homes below Bendemeer. “The Terraces” picks up fine sediment as it flows downhill toward the lake. Left unchecked, that sediment would wash straight into Lake Hayes, feeding the same phosphorus problem FOLH has spent years working to reverse.

Instead, a series of shallow swales along the shoreline slows the water down and lets it pool. As the water sits, sediment drops out of suspension and settles on the swale floor rather than continuing into the lake. Only then does the (much cleaner) water soak away or make its final, short journey into Lake Hayes.

It’s a simple idea, but the photos make the scale of it obvious: tonnes of sediment has settled out in these swales over just this one winter – sediment that, without this system, would have gone straight into the lake.

It’s also a useful reminder of just how much fine sediment is moving through our catchment from urban and hillside run-off alone, well away from the farm sites where most of our extraction effort is focused. Every hillside, every driveway, every bit of exposed soil is a potential sediment source – and small, low-cost interventions like these swales are a cheap and effective way to intercept it before it becomes the lake’s problem.