Stormwater Design, SPCC, Sampling & Inspection Services

From The Summit

Tips, Tricks and Expertise from the Summit Team.

What’s in a SWMP?

It’s in the Details

Check our resource section for copies of the state guidance document and the state SWMP inspection checklist. These are most complete and authoritative sources for answers to the question: What’s in a SWMP? For a quick overview of what is in a SWMP, read on, my friend, read on.

When is a SWMP needed?

When you have a project that requires a state stormwater permit (a Colorado Stormwater Discharge Permit) you will also need a Stormwater Management Plan. This plan is what you, as a project owner, or developer, or builder, commit to doing on your active construction project to limit pollution from leaving your project and impacting surrounding properties and waterway.

Your SWMP becomes the yardstick by which compliance is measured on your site.

Caveat: You may also have a local permit and plan. These are required to be at least as stringent as the state requirements, and in same cases are more strict than the state. In this blog, we are only addressing the state level SWMP.

Who writes the SWMP?

So, the SWMP is the yardstick. It is how compliance success is measured. The good news is that YOU, or your representative, write the SWMP so you have a lot of latitude in setting the standards for compliance. In the past, this was often written by the civil engineer for the project. More and more often the SWMP is now written by a Stormwater Consultant such as Summit Services Group.

More good news about the SWMP is that you are permitted to modify it over the course of the project to adjust for changing conditions. For example, if you found that one BMP was high maintenance and costly, you can substitute another BMP, as long as you can reasonably make the case that the replacement BMP is suitable for use in that specific situation.

What are the elements of a SWMP?

The SWMP can be thought of as two big pieces. One is the narrative section. It answers a lot of questions about the project that define the risks and the risk mitigating methods present on the projects. The other piece is the maps and BMP details which give a more visual representation of pollution prevention methods used.

What is the narrative portion of the SWMP?

As noted above, a more comprehensive description is available in the state documents in our resource section. For the overview, consider the key elements of the SWMP.

  • Identifying information for the project. Location, project description, contact information, etc.
  • Identification of potential pollutants
  • List of BMPs used for each potential pollutant
  • Description of inspection and maintenance
  • The plan for final stabilization (to allow permit closure).

What is the map portion of the SWMP?

The maps and the BMP details are essentially a visual representation of the site, the location of BMPs (often shown in phases), and construction details showing the “how to” of BMP installation.

Things to consider:

  • The SWMP sets the standard, so choose wisely when you write it. The choices you make in writing the SWMP can mean the difference between low maintenance and high maintenance, low cost or higher cost.
  • The SWMP can be revised, but the SWMP narrative and map should always match what is used on site. If you change one (narrative, map, site usage), change all to match.
  • If you make a change to a SWMP, it should be defensible, meaning that you can look a regulator in the eye and confidently give a solid reason for the change.
  • Your SWMP should be initialed and dated each time there is a change.
  • Your SWMP, permit, inspection reports, and maps are all subject to review by the state as a condition of getting a stormwater permit. They have a legal right to review all these documents.

We hope that answers a few of your stormwater compliance questions. Please check in with us if you need further clarity. Also, feel free to send us a question that you’d like to see in a future post. If you have a question, others are likely to have the same question.