What type of impact does impervious surface cover have on stormwater runoff?

Impervious surfaces, such as roads, rooftops, and parking lots, significantly influence stormwater runoff by increasing its volume and speed. These surfaces do not allow water to penetrate into the ground, which results in more water flowing directly into storm drains and waterways during rainfall events. As more impervious surfaces are created within a watershed, the natural processes of infiltration and evaporation are disrupted, leading to higher peak runoff rates and greater overall quantities of runoff entering streams and rivers.

This increased runoff can lead to several environmental concerns, including flooding, erosion, and the transport of pollutants into aquatic systems. Managing impervious surfaces and implementing practices such as green infrastructure can help mitigate these impacts by reducing the volume of runoff and enhancing the natural water cycle processes.