Watershed Overview

All water that hits the surface within the boundary of the identified area eventually makes its way to Lake Auburn. When water from precipitation or another event – even drainage from landscaping – flows over the landscape of the watershed, this is considering surface water runoff. 

The most problematic surface areas when it comes to runoff are impervious surfaces, which include roads, parking lots, buildings, and even compacted soil. These surfaces prohibit the absorption of water and instead allow water to quickly flow across them. In addition, water collects pollutants as it comes into contact with them. So, as surface runoff moves fast over impervious surfaces, it picks up contaminants, delivering them directly into Lake Auburn.
 
In comparison, permeable surfaces are porous surfaces that allow water to move and filter through them, working in a similar way that a kitchen sponge can absorb and hold water. Most vegetated areas are permeable surfaces. When water travels over permeable surfaces, it is absorbed into the soil. The soil, vegetation, and microbes filter pollutants from the water, allowing cleaner water to slowly travel through the watershed. Native vegetated areas are vital in our watershed for their ability to slow the flow and filter out pollutants from our water. 

Many of the watershed protection efforts initiated by Lake Auburn Watershed Protection Commission directly involve controlling surface run off by eliminating impervious surface cover and protecting permeable surfaces as well. This includes everything from small-scale planting efforts to large scale land conservation efforts, all seeking to keep contaminants out of Auburn and Lewiston’s drinking water source. Read more about how LAWPC helps the watershed. 

The map above shows the breakdown of forested versus non-forested land cover in the watershed as of 2026. Two large sections of non-forest land exist to the southeast and to the north of Lake Auburn. Thanks to the protections initiated by Auburn Water District, the City of Auburn, and Lake Auburn Watershed Protection Commission, noting both land conservation and zoning provisions, the watershed remains largely forested. These lands serve as an important buffer to reduce run off to Lake Auburn.