Colorado E. coli Toolbox

Over 90 stream segments in Colorado are identified as impaired for recreation use due to elevated concentrations of E. coli (fecal indicator bacteria) or in need of further monitoring and evaluation for E. coli.  Once a stream is identified as impaired, a total maximum daily load (TMDL) and associated discharge permit requirements affect municipal storm sewer system (MS4) permittees.  At the request of the Mile High Flood District and the City and County of Denver, WWE and Geosyntec developed an E. coli Toolbox for Colorado MS4s that need assistance in understanding the regulatory implications of E. coli impairments, source investigation strategies, data interpretation, source controls, BMP performance, and regulatory alternatives.

After completion of the toolbox, WWE led development of topic-specific fact sheets for use by MS4s in communicating among internal departments, city councils, and the public. The guidance supports Denver Metro-area local governments in identifying sources of fecal contamination, developing plans to address these sources through implementation of programmatic and structural measures, and providing guidance on advanced microbial source tracking techniques that can be used to support alternative regulatory solutions. These resources are publicly available at https://udfcd.org/.