This guidance is for small construction projects disturbing less than one acre located – within 100 horizontal feet of waterways.
When is a SWQP required?
SWQP are required when working within 100 horizontal feet of a waterway or underneath a waterway, even when land disturbance is less than one acre unless a SWQP Exemption Form is submitted and accepted by Boulder County.
Waterway Definition – Waterway is defined by the watercourse definition in Boulder County Land Use Code Article 18-213A. “A channel, natural depression, slough, artificial channel, gulch, arroyo, stream, creek, pond, reservoir or lake, including major drainageways, in which stormwater runoff and floodwater flow, either regularly or infrequently.”
These waterways are depicted as blue lines on the Boulder County Stormwater Map. SWQPs will not be required for small projects (less than an acre of disturbance) in or near irrigation laterals or ditches.
Working near waterways poses a higher risk to impact water quality which is why Boulder County requires Stormwater Quality Permits (SWQP) for projects working near waterways that are less than one acre. This guidance is intended to be supplemental to the Boulder County Guidance for Work in Waterways.
What project may qualify for an SWQP Exemption?
When a project’s construction activities are deemed to be low risk and less than an acre, a determination can be made that a SWQP is not required. The applicant must provide a completed SWQP Exception Request Form to stormwater@bouldercounty.gov to determine if Boulder County will approve the exemption.
These determinations will be made on a case-by-case basis by the County Engineer and will be based on the low risk factors listed below.
- Duration – Shorter projects (typically less than three weeks in duration) that are less than one acre but within 100 horizontal feet may be eligible for a SWQP Exemption.
- Nature of construction activities – Projects that have minimal earthwork such as a barn or shed without a foundation, small solar arrays, small patios, and trails that are more than 50 feet from the waterway may be eligible for a SWQP exemption.
- Slope – Steeper disturbed slopes upgradient of the waterway and within the project area may influence the need for a SWQP when working near waterways. For example, if the site is within 100 feet of a waterway but the topography is such that the waterway is upgradient from the disturbance, then the project may be eligible for a SWQP exemption.
If a SWQP is not required, what is needed?
Even if a SWQP is not required, using control measures is essential and mandatory. Control measures will help minimize the risk of negative impacts to water quality. All construction projects regardless of size require the use of control measures.
SWQP Submittal Requirements for Small Projects near Waterways:
- Completed SWQP application,
- Completed SWQP Checklist for Small Projects,
- Site maps meeting requirements listed on checklist. Additionally, the general principles outlined in the Storm Drainage Criteria Manual (SDCM, Section 1302.1) should be reviewed and considered in the design of the site maps and placement of control measures,
- Control measure details.
MS4 Compliance Oversight for SWQP Small Projects near Waterways
The County will require an initial inspection of the control measures and final inspection by the County’s MS4 Stormwater Inspector to ensure the site has appropriate controls prior to construction and is stabilized after construction is completed.
For any additional questions, contact the Public Works Department at stormwater@bouldercounty.gov or 303-682-6757.