Nature of Activity: The City of Boulder is implementing a program in which the City pays for various nonpoint source improvements rather than capital upgrades at its POTW. The City found that a large capital improvement project at the POTW would be more costly and less effective than a combination of more modest capital improvements with streambank stabilization, riparian corridor improvements, rerouting irrigation return flow through wetlands, and other measures. 

Environmental Problem: Degraded habitat, nonpoint source pollution, ammonia toxicity and high temperature combined to prevent Boulder Creek from attaining its designated beneficial use of Warm Water Aquatic Life.

Pollutant(s) / Pollution Type(s): Ammonia, temperature, pH.

Trade Types: Point/nonpoint.

Stage of Implementation: The City has been implementing the program since 1990.

Relation to TMDL: The basin is on the State’s list of waters not meeting water quality standards and for which TMDLs must be developed (the 303(d) list) and a TMDL study will be performed over the next two to three years.

Number of Potential Participants: The City of Boulder and various nonpoint sources.

Trading Ratios: N/A

Estimated Cost Savings: Through 1996, the City had spent approximately $1.4 million and saved between $3 – 7 million, resulting in a estimated net savings of $ 1.6 – 5.6 million.

Available Written Information: Brief summaries are available from U.S. EPA and from U.S. EPA Region 9.

Innovative Aspects: The objective of improving the aquatic ecosystem is being achieved more cost-effectively through a combination of source controls, in-stream and riparian restoration efforts than could be achieved through more intensive source controls alone.

Obstacles: Unknown

Web Sites: St. Vrain: http://www.epa.gov/surf2/hucs/10190005/

Contact: Greg Parsons, Colorado Department of Public Health and Environment, (303) 692-3500,