Snoqualmie uses a number of systems to control stormwater runoff, increasing the quality of water entering the Snoqualmie River, improving its environmental impacts, and decreasing run-off volumes and the chance of local flooding.  Even simple management practices, such as the following can greatly affect runoff impacts in a city.

Bioswales
Bioswales are gently sloping landscaping, generally at a grade of 6% or less, that line roadsides and walkways. They allow water to collect and absorb in the ground.  Bioswales are designed to maximize the amount of time the water spends in the swale, while their vegetation filters silt, organic chemicals, heavy metals, and other harmful particles from the water.

Retention Ponds
Retention ponds are often referred to as water quality ponds. They function to naturally break down and capture contaminants prior to releasing the water into the natural environment. They are also designed to help keep local wetlands and small streams healthy and functional.

Snoqualmie uses a system of retention ponds to contain and regulate the city’s runoff.  These ponds are designed to receive a large amount of runoff and discharge it slowly to manage the amount of water that enters the Snoqualmie River. This system of water management helps reduce the risk of flooding in communities near lakes and rivers.

Storm Filters
Municipal storm drains can be fitted with filters that remove debris from stormwater runoff.

Urban Forestry Program
The urban forest in Snoqualmie effectively reduces and filters the stormwater runoff.