Introduction to Phase II Stormwater Program

The E-470 Public Highway Authority is covered by a Phase II Stormwater Management Permit for the limits of the Cherry Creek Drainage Basin.  The limits for the permit are along E-470 from Jamaica Street (near I-25 South) to Smoky Hill Road.  The permit is based on legislation by the U.S. Environmental Protection Agency (EPA), through the National Pollutant Discharge Elimination System (NPDES) Program requirements of the Federal Clean Water Act, and the regulations promulgated by the Colorado Department of Public Health and Environment (CDPHE) – Water Quality Control Division (WQCD) in their Phase II Stormwater Program.    E-470’s permit was issued from March 2008 to March 2013. 

The primary function of storm sewer systems, including natural channels, is the collection, conveyance, and storage of stormwater runoff.  In a watershed-based approach to urban stormwater management, the municipal separate storm sewer system (MS4), including both structural (e.g. pipes, inlets and outlets) and natural drainage ways, is an important component.

E-470 is required to ensure compliance with all applicable water quality regulations related to stormwater runoff, including and in particular, both the WQCD’s Stormwater Phase II Program and the Cherry Creek Reservoir Control Regulations.

E-470 is required to ensure E-470 MS4 facilities are functioning and well maintained and is committed to protect the overall water of the E-470 water runoff.

When the roadway is widened to more than one acre, E-470 is required to construct permanent Best Management Practices (BMP).   Permanent BMP were constructed when the roadway was widened from the toll plaza (east of Peoria) to the Cherry Creek Bridge and the Jordan Road ramp dualization project.

E-470 is required to prohibit any material other than stormwater into a storm sewer system or discharge any substance in violation of any state or federal law or regulation, under the illicit discharge detection elimination plan.  The discharging, spilling, dumping or disposal of the following is not prohibited:  landscape irrigation flows; diverted stream flows; rising ground waters;  uncontaminated pumped ground water; discharges from potable water sources;  drainage collected by foundation drains; air conditioning condensation; irrigation water; spring water; discharge from crawl space pumps; drainage collected by footing drains; flows from individual residential care washing; individual residential swimming pool and hot tub discharges; flows from water line flushing; flows from riparian habitats and wetlands; flows from emergency fire fighting activities; and street wash water associated with construction activities pursuant to a current, valid E-470 construction permit that authorizes such discharges, provided that the permittee develops and implements appropriate control measures, approved by E-470, to minimize the impacts from this source.

Stormwater Hotline:  Call 303-537-3470 to report an illicit discharge.

Click here to review the stormwater permit