Stormwater Quality Permit

Stormwater Quality Permit (SWQP)

County SWQP Information

As part of Boulder County’s water quality protection and municipal separate storm sewer system (MS4) construction program, a stormwater quality permit (SWQP) is required for construction projects that:

  • Disturb one acre or more in size;
  • Are less than one acre and construction activity is part of a larger common plan of development that will ultimately disturb one acre or more, even if multiple, separate, and distinct land development activities may take place at different times; or,
  • Are within 100 horizontal feet of a watercourse.

The County Engineer may require a SWQP regardless of the size of the total disturbed area, in conjunction with approval of a final subdivision plat, special use permit, or other site specific development plan under the Land Use Code, or if construction is adjacent to a watercourse or wetlands. Boulder County is required by the Environmental Protection Agency (EPA) and the Colorado Department of Public Health and Environment (CDPHE) to maintain a Stormwater Management Program.

Detailed requirements are listed in Article 7-904 of the Boulder County Land Use Code

Stormwater Management is Important

Polluted stormwater runoff from construction sites often flows to storm drain systems and is ultimately discharged into local streams and rivers, destroying aquatic habitat. Sediment is usually the main pollutant of concern, but there are others:

  • Solid and sanitary wastes
  • Phosphorus and nitrogen from fertilizers
  • Concrete from washouts
  • Construction chemicals, debris, and trash
  • Oil and grease
  • Pesticides

Sedimentation runoff from construction sites is typically 10 to 20 times greater than those from agricultural lands, and 1,000 to 2,000 times greater than those from forested lands.

Important Permit Information & Requirements

Please contact Stormwater Quality Permitting Staff well in advance of any project to determine what is exactly required, but a complete application packet will include:

  1. Signature by the landowner or the owner’s authorized representative and identification of the operator and other persons legally responsible for compliance with the permit, including the assigned erosion control supervisor as required in Boulder County Land Use Code 7-904F.3.d. The County Engineer shall have the discretion to require that persons identified as operators, or other persons who are known at the time of application as being responsible for implementation of any approved permit, sign the application as applicants.
  2. Documentation of an application for a CDPHE stormwater general permit for construction. This documentation should consist of a letter from the Water Quality Control Division of the CDPHE that assigns a certification number to the project (if available).
  3. A Stormwater Management Plan (SWMP) that includes but is not limited to:
    1. A project description that includes the location and extents of the project, a summary of the construction to be completed, and the end product;
    2. Best Management Practices (BMPs) to be installed on a temporary basis as necessary to control stormwater discharges from the construction site before and during construction until final stabilization. This includes a narrative describing nonstructural BMPs such as construction site phasing (e.g., phase of the project so that vegetation will remain in those areas and will not have construction activity at the start of the project);
    3. A site plan (or plans) depicting the affected site in sufficient detail to show significant site features (natural and man-made), areas proposed to be disturbed and developed, existing easement areas and restricted development areas, and locations of proposed temporary BMPs; and,
      1. NOTE – Projects disturbing under 1-acre but within 100 horizontal feet of a watercourse require Site Plans, BMP details, and a SWQP checklist for small projects.
    4. Identification of any affected MS4 or waters of the state anticipated to receive stormwater discharge from the site;
    5. Checklists for the SWQP.
    6. AND – After after the SWQP is issued, the SWMP must accurately reflect current site conditions at all times. Minor and substantial modifications to the SWMP and the approved permit must meet the requirements in Land Use Code Article 7-904G.

For construction activity disturbing one acre or more within the urbanized area, you will also need:

  • A final drainage plan and report that follows the county’s Storm Drainage Criteria Manual (SDCM) and includes a narrative describing the proposed post-construction controls (permanent BMPs) and methods for perpetual maintenance. This must be stamped by a Colorado Professional Engineer;
  • A site plan showing locations of the proposed post-construction controls;
  • Identification of the parties responsible for perpetual maintenance of proposed post construction controls;
  • Operating and maintenance (O&M) plan and easement for county inspection and access;
  • SDI Design data sheets (download the data sheets)
  • Post-Construction Review Checklist; and,
  • As-Builts once the post construction control has been completed.

Design, installation, and maintenance specifications for all BMPs included in the SWMP and the site plans and installed at the site are required to part of the SWMP. All BMPs designed to meet the requirements shall generally comply with:

*NOTE – The County Engineer reserves the discretion to require additional information deemed necessary for adequate processing of the application.

Payment of a permit fee will be an amount determined by the County Engineer as what is reasonably necessary to defray the costs of administering the county’s stormwater quality program.

  • The permittee must keep the accepted SWMP on-site at all times and shall make the SWMP available for inspection upon request by the County Engineer
  • The permittee shall provide timely installation and maintenance of all required temporary and permanent BMPs required in the SWMP. Non-functioning, damaged, or destroyed BMPs shall be repaired and/or restored immediately. All BMP maintenance, repair, and restoration shall be documented on the accepted SWMP and available for County Engineer inspection.
  • The permittee shall inspect all temporary BMPs at least every 14-days and within 24-hours after any precipitation or snowmelt event that causes surface runoff. An erosion control supervisor (ECS) must conduct all BMP inspections and keep a detailed record as part of the SWMP. The ECS is the same as a SWMP Administrator as described in the General Stormwater Permit issued by the CDPHE.

By accepting the permit, the permittee consents, both for itself and for its successors in interest, to allow the County Engineer and associated county agents access to the property subject to the permit for the purposes of inspecting compliance with the permit. County access and inspection may occur at any time for this purpose and without prior notice to the permittee.

If construction is completed and seeding and final stabilization practices have been implemented, a reduced inspection frequency may be requested by scheduling a site meeting with the designated MS4 Compliance Inspector. Contact the Transportation Department (info below) if you don’t know who is designated as your MS4 Compliance Inspector.

If construction is completed and the site meets the items listed below, a close out inspection may be scheduled with the designated MS4 Compliance Inspector:

  • All areas have achieved final stabilization (70% of pre-disturbance vegetation with uniform density on areas not stabilized with other non-erosive surfaces)
  • All work areas have been left free of sediment and construction debris/waste
  • No evidence of damage from the contractor to public infrastructure

After the MS4 Compliance Inspector determines the above conditions have been met, any temporary erosion and sediment control measures must be removed in order to have the permit closed.

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