Stormwater Pollution and Treatment Education

Importance of Stormwater Care

Pollution from stormwater runoff is a major concern, especially in urban and sub-urban areas. Rainwater washing across streets and sidewalks can pick up spilled oil, detergents, solvents, de-icing salt, pesticides, fertilizer, and bacteria from pet waste.

  • Drainage- Aspen’s stormwater drains do not channel water to a treatment facility. Though a good majority the urban core is carried to the Jennie Adair wetlands, a bio-engineered detention area, before making its way to the Roaring Fork River, the remainder of the city’s runoff flows directly into the Roaring fork river, Hallam lake, and other neighboring waterbodies within the city limits.
  • Surface Pollutants & Runoff- Most surface pollutants are collected during the first one-quarter inch of rainfall or "first-flush" in any storm or snowmelt event. This is the period when the majority of pathogens, sediment, waste, and debris are picked up by flow across lawns and roadways. The runoff is then carried untreated into waterways, these materials become "non-point source pollutants" which can increase algae content, reduce aquatic life, and require additional costly treatment to make the water potable for downstream water systems.

Best Management Practices

Best Management Practices (BMPs) are actions done to control water pollution and improve water quality. Throughout Aspen many BMPs are implemented to reduce runoff and keep pollutants out of the Roaring Fork River. Below is a summary of BMPs that are utilized in Aspen. Further information on BMPs can be found in the Urban Runoff Management Plan in the sections listed with each summary.

  1. Street Sweeping- Street sweeping plays an important role in keeping pollutants out of stormwater. Debris, dirt, sand and silt collect in gutters and along the sides of streets. Sweeping and collecting this material keeps it from entering the river.
  2. Vaults- The city of Aspen has installed vaults to help improve stormwater quality. Sediment stays suspended in water when water moves. You can visualize this by picturing a jar filled with water and dirt. When you shake the jar the dirt mixes with the water and the water becomes murky. However, if you leave the jar sitting on a table the dirt will eventually settle to the bottom. Stormwater vaults work in the same manner. Water running off the streets is turbulent, mixed, and carries high concentrations of sediment. When the water reaches a vault a couple things happen that remove unwanted pollutants. First, the water passes through a trash rack. A trash rack is a series of bars that stop large debris. The water also slows down greatly. The water is deep and slow moving. This allows sediment to settle to the bottom of the vaults. The water then has to pass under a structure which essentially “skims off” any pollutants floating on the water. This helps keep oil and gas, which floats on top of water, out of the river. At the end of the vault a structure comes up from the bottom of the vault. Only water on top pours over and out of the vault. This keeps the sediment on the bottom from flowing out of the vault. Aspen has vaults located above the Jenny Adair wetlands located on the south side of Puppy Smith Street, as well as underneath the parking area in the Rio Grande Recycle Center. The Jenny Adair vaults treat stormwater that drains from nearly the entire town west of Mill St, while the Rio Grande Recycle Center treats drainage from the east and middle portion of town as well as drainage from Aspen Mountain’s two major gulches, Copper and Spar.

Section of the Urban Runoff Management Plan (PDF) has more information and specific requirements for stormwater vaults in the City of Aspen.

Bioengineered Wetland - Jenny Adair Wetlands

A constructed wetlands basin is a shallow retention pond that has a continuous base flow which promotes the growth of rushes, willows, cattails and reeds. The shallow pond, along with vegetation, slows down runoff and allows time for sedimentation, filtering, and biological uptake. Wetlands greatly improve water quality while at the same time providing natural aesthetic areas, increasing wildlife habitat, and providing erosion control. Constructed wetlands are engineered to mimic natural wetlands which can be viewed as the “kidneys” of the hydrologic cycle due to their filtering and cleansing capabilities.

More information on constructed wetland basins can be found in section of the Urban Runoff Management Plan (PDF).

Types of Pollutants

Harmful Waste Bacteria- Pet, wildlife and human waste all carry harmful bacteria. When collected by runoff, the waste is easily transported to nearby waterways. This bacteria contaminates water and can cause diseases and dangerous infections in both people and animals.

Properly Dispose Pet Waste- Please pick up after your pet and dispose of waste properly in the toilet or trash. Aspen has biodegradable pet waste bags strategically placed around the City's open space and trails. Failure to pick up after your pet is a ticket-able offense in Aspen. If you have a septic system, follow proper maintenance procedures to prevent overflow or seepage. If you suspect a sanitary sewer is malfunctioning, contact your local authority immediately.

Flooding Information

The City of Aspen participates in the National Flood Insurance Program (NFIP) and encourages all owners with land in the 100 year floodplain to visit, the official site of the NFIP, to receive more information on flood insurance.