Stormwater Management Program Review

Description

The mission of the City's Stormwater Utility is to protect public health and safety, natural resources, waterways, and our aquifer, while meeting or exceeding state and federal environmental quality regulations. The Utility developed a Stormwater Management Program (SWMP) not only to comply with the state Municipal Separate Storm Sewer System (MS4) permit but also as a tool for achieving its mission. As a condition of the permit, the Utility must solicit feedback on the SWMP from community stakeholders and the general public. A link to the the Stormwater Utility's most recent version of the SWMP document is provided below.

UPDATED for 2024—The SWMP update for 2024 is now available for review. Please use the link below to access the SWMP and appendices, then use the Comments & Questions tab at the bottom of the page to let us know what you think about the plan.

Stormwater Management Program - February 2024 (pdf)

Appendix A: City of Missoula Stormwater Infrastructure Maps

Appendix B: Missoula Valley Water Quality District documents

Appendix C: Outfall Reconnaissance

Appendix D: Illicit Discharge Investigations – 2020

Appendix E: City of Missoula Stormwater Specifications and Design Standards

Appendix F: City of Missoula Stormwater Utility Standard Drawings

Appendix G: Chapter 13.27, Missoula Municipal Code

Appendix H: City Stormwater Permit and Checklists

Appendix I: Water Sampling Plan

Appendix J: Standard Operating Procedures for Municipal Operations

Appendix K: Post-Construction

Appendix L: Public Outreach

Background

Nonpoint source pollution, like stormwater runoff, is a significant problem in Montana and the single largest cause of impaired waters statewide according to the Montana Department of Natural Resources and Conservation. The City of Missoula's Stormwater Utility manages the quantity, quality, and routing of stormwater runoff through our community. The effectiveness and efficiency of stormwater management have a direct impact on public health and safety, surface water quality, wildlife habitat, and future development.

Consequently, the federal government amended the Clean Water Act of 1972 in 1987 to regulate the management of stormwater runoff from municipalities and specific industrial classifications. Federal and state regulations require designated municipalities obtain and maintain coverage under the Montana Pollutant Discharge Elimination System General Permit for Storm Water Discharges Associated with Small Municipal Separate Storm Sewer Systems (MS4 Permit), which is administered by the Montana Department of Environmental Quality under the authority of the U.S. Environmental Protection Agency. For more information on the MS4 permit, please view this slideshow presentation.

This SWMP covers required elements the City has already implemented, is in the process of developing for implementation, or plans to develop in order to meet new or revised requirements set forth in the latest statewide requirements. The six Minimum Control Measures (MCMs) below are required under the MS4 Permit and are addressed in the SWMP. The measures apply to the Stormwater Division itself, requirements for construction sites, and requirements related to other City departments and activities.

• MCM 1—Public Education and Outreach – The City must continue to educate the public in its permitted jurisdiction about the importance of the stormwater program and the public's role in that program.
• MCM 2—Public Involvement and Participation – The City must continue to comply with all state and local notice requirements when implementing a public involvement/participation program.
• MCM 3—Illicit Discharge Detection and Elimination – The City must continue to adopt and enforce City of Missoula ordinances or take equivalent measures to prohibit illicit discharges. The City must also implement a program to detect illicit discharges.
• MCM 4—Construction Site Stormwater Management – The City must continue to develop a program to control the discharge of pollutants from construction sites within its permittee jurisdiction.
• MCM 5—Post‐Construction Site Stormwater Management in New and Redevelopment – The City must continue to require long‐term post‐construction best management practices (BMPs) that protect water quality and control runoff flow to be incorporated into development and significant redevelopment projects.
• MCM 6—Pollution Prevention/Good Housekeeping for Permittee Operations – The City must continue to examine its activities and develop programs to prevent the discharge of pollutants from these activities. The City must also educate staff on pollution prevention practices.

Through these MCMs, the SWMP aims to reduce the discharge of pollutants from the City's stormwater system to the maximum extent practicable and to protect water quality.