But, when rain falls on developed lands, impervious surfaces prevent water from soaking in and instead it runs off and into waterways or storm systems which eventually dump into surface waters. In the process of running off, stormwater picks up pollutants on the ground’s surface – like nutrients, pet waste, debris, oil particles and trash. These pollutants contribute to poor water quality.
Why is it a problem for Lake Champlain and the people of Vermont?
Vermont’s largest urban centers are located in the Champlain watershed. Population increases over the past two decades have led to greater development in the Champlain Valley which means more impervious surfaces. All these roads, driveways, parking lots and building roofs increase the amount of water that reaches rivers and lakes quickly, as surface runoff. This water is dirty (because it picks up pollutants from the surface it speeds over) and there is way too much of it at once for streams and rivers to handle. When these “flashy” storm events come, waterways are stressed and damaged leading to negative impacts on water quality, aquatic organism habitat and recreational conditions. The sediment that the rivers are carrying can be increased as large water volumes erode stream banks. That sediment carries nutrients which end up in Lake Champlain and lead to toxic blue green algae blooms, beach closures, fish die offs and ecological imbalance.
In recent years we have been experiencing fewer but more significant ran events. All these impervious surfaces decrease our flood resiliency – making our infrastructure more vulnerable to rivers overflowing their banks.