Boulder Stormwater Management

Regulatory Compliance

The Stormwater Quality Program assures compliance with all state and federal water quality regulations related to stormwater. The City of Boulder's municipal separate storm sewer system operates with a permit from the Colorado Department of Public Health and Environment. In compliance with requirement Part I.D.1.b of the Phase II MS4 permit, the city’s Program Description Document is publically available for review and comment by contacting the Stormwater Quality Program.

The permit sets requirements related to six minimum control measures:

  • public education and outreach;
  • public participation;
  • illicit discharge detection and elimination;
  • construction site runoff control;
  • post-construction runoff control; and
  • pollution prevention and good housekeeping.

In addition to stormwater regulations for municipalities, federal regulations require certain industrial facilities to obtain a stormwater discharge permit. City-owned facilities such as the Wastewater Treatment Facility and the Boulder Municipal Airport are included in these current Industrial Pretreatment regulations. Stormwater discharges associated with construction activities are also required to obtain a permit.

Boulder County Storm Drainage Criteria Manual

Section 1200 Detention and Permanent Water Quality

This section presents the criteria for design and evaluation of all detention and water quality facilities
for Boulder County. The main purpose of a detention facility has historically been to store the excess storm runoff associated with increased basin imperviousness and discharge this excess at a rate similar to the rate experienced before development. In recent years, detention facilities have also frequently been viewed as a unique opportunity to improve the water quality of runoff coming from developed areas. This runoff typically carries higher levels of nitrogen, phosphorus, and sediment that can damage the ecosystems of the natural streams downstream of the development. This section discusses detention both with and without a water quality component; water quality facilities located outside a detention basin, including proprietary facilities; and when detention and water quality are required.

1203.3 Maintenance of Detention Facilities and 1204.5 Maintenance Requirements of Permanent Water Quality Treatment

The performance of detention facilities is extremely sensitive to a lack of maintenance. Detention facility outlets in particular must be regularly maintained to ensure the basins meet the requirements of Colorado water law and do not detain water longer than allowable. If detention is to be constructed, Boulder County requires an enforceable maintenance agreement to be in place before issuing any applicable local permits. The agreement must include the party responsible for maintaining the facility,inspection frequency, and proposed maintenance activities.

Boulder City Stormwater Master Plan

9.8.1 Operations and Maintenance Program (MCM 5 and 6) 

This section describes the city’s current stormwater O&M program. O&M is included in both MCM 5 and MCM 6 in the 2008 MS4 permit. The section describes standard maintenance of the stormwater system and permanent stormwater BMPs, the stormwater repair and rehabilitation program, and monitoring and sampling of the stormwater system. Permanent BMP Inspection Currently, the city follows a stormwater maintenance schedule for permanent BMPs in the city. Above-ground private BMPs are inspected per state requirements and the responsible party is expected to maintain them. Stormceptors™ and other proprietary BMPs are currently used in the city’s storm drain system, but there is no stormwater maintenance schedule for these or any othercity-owned BMPs. Private ponds are inspected and are entered into the city’s database. The city does not perform in-depth inspections of private proprietary BMPs, such as Stormceptors™. Recently, the city implemented a GIS-based asset management tool for tracking city-owned, proprietary, and other BMPs. The city is also trying to better organize and use as-built drawings for city projects. These are good first steps to creating consistency in maintenance and inspection schedules.


Boulder City Stormwater Quality Overview

Boulder City Stormwater Master Plan

Boulder County Storm Drainage Manual


If you need any additional information about Boulder stormwater management, please reach out to the experts at Aqualis! We have the knowledge and experience needed in stormwater maintenance and repairs to ensure you are compliant.