Impervious surfaces, such as roads, driveways and roofs, shed water instead of allowing water to absorb into the ground (infiltration). Instead, water is forced to stay on the surface becoming runoff. The runoff flows down hill to the nearest stream or creek, often carrying sediment or pollution along with it. The path rain takes as it's traveling to the creeks and rivers greatly impacts the health of those creeks. Impervious surfaces can cause many problems such as flooding, increased stream temperatures and changes to the physical and biological health of the stream. Findings reveal that stream degradation consistently occurs when impervious surface levels in a watershed reach between 10-20%.