the Built Environment Paving large expanses of land increases runoff of pollutants into streams and rivers that eventually wash into Puget Sound. This impact is evident in the fact that salmon have large quantities of PCBs in their bodies. In 2007 the Department of Health issued a consumption advisory warning against eating Puget Sound salmon. Since 1991, there has been a marked increase in the amount of impervious surfaces in the Greater Puget Sound area. Impervious surfaces are man-made structures such as roads, house foundations and roofs that prevent water from being absorbed and filtered through the soil. Stormwater management systems have reached their capacity to catch and treat this runoff water. Sudden increases in stream flow that occur during high rainfall can be greatly exacerbated by urbanization that replaces natural vegetation with pavement or rooftops. The Department of Ecology found that surface runoff is the largest source of toxic chemicals being deposited into Puget Sound. Streams drain directly into Puget Sound from roads, driveways and rooftops, without benefit of filtration. It is possible to reduce pollution of streams and rivers by using Low Impact Development (LID) methods in construction projects. These low-impact development methods are environmentally friendly by reducing the amount of storm water runoff that reaches Puget Sound. These building methods not only help Puget Sound salmon, but also benefit humans through increasing property values, and enhancing aesthetic appeal. Rain gardens Salmon friendly gardens, also called rain gardens, would prevent overflow and surges and would absorb pollutants which would otherwise be washed directly into freshwater systems. When a storm causes rainwater to surge into rivers and streams via storm drains, the heavy flow of fast moving water commonly erodes the soil thus destroying precious salmon and steelhead habitat. Said storm drain surges are typically warmer in temperature than the water of the streams into which they are being deposited. This causes river and stream temperatures to rise and places further stress on growing and migrating salmon and steelhead. The salmon friendly gardens are planted as depressions in the ground, and work by absorbing much of the rainwater runoff which is redirected to first flow through the gardens before ultimately ending up in the rivers and streams. The gardens therefore slow and lessen the storm surges and filter out pollutants being washed out of the city. Planting rain gardens would result in less erosion, lower and stable water temperatures,