As stormwater flows over the land, it can pick up pollutants. Common pollutants in urban systems include:
• Bacteria – from pet and wildlife waste, and failing septic systems
• Phosphorus – from tree leaves, grass clippings, soil erosion, fertilizer, and pet and wildlife waste
• Sediment – from exposed soil on construction sites, sparse lawns, and unprotected garden beds set close to hard surfaces like streets, sidewalks, and driveways
• Chloride – from road salt
• Trash

Unlike the water that goes into a drain inside your home, stormwater does not get routed to a treatment plant to get cleaned. Instead, stormwater is routed directly to local lakes, ponds, wetlands, and creeks. Learn more about the city’s pollution prevention efforts and how you can do your part.

Stormwater can also cause flooding and drainage issues when the stormwater management network is overwhelmed. Sometimes parks and streets are used to temporarily store water during and after a storm in order to protect downstream structures and waterbodies. If you’re unsure whether standing water is planned or if there is a problem, contact the Engineering Department.

Porous Pavement

Concrete and asphalt roads, driveways and walkways prevent water from soaking into the ground. When given the choice, consider alternative materials for walkways, driveways and patios. Where you need a more solid surface, consider using a "porous pavement" made from interlocking blocks that allow spaces for rainwater to soak into the ground. If you choose to pour concrete or asphalt, keep the paved area as short and narrow as possible.

Riparian Buffers

Riparian buffers are upland areas adjacent to streams, lakes, wetlands or other surface water. Leaving a natural, undisturbed strip of land along water bodies provides a transition zone between the surface water and the land use upstream. This transition zone is called a riparian buffer, or more simply, a buffer.

Buffers along rivers, streams, lakes and wetlands diffuse stormwater runoff, maintain bank stability, and remove nitrogen, phosphorous, and other pollutants from stormwater before it reaches waterways. Stream buffers are also complex ecosystems that provide habitat and improve the health of the wildlife they shelter, as well as open space for people to enjoy. For riparian buffers to be most beneficial, they must remain undisturbed in their natural state. A healthy buffer of native vegetation is an effective tool for protecting water resources.