Trout Brook Storm Sewer Interceptor

Originally built between the 1880s and 1950s, the Trout Brook Storm Sewer once served as a combined sanitary and storm sewer. In 1988, the combined system was separated and the Trout Brook Storm Sewer Interceptor (TBI) remained. CRWD replaced the Metropolitan Council as owner and operator in 2006. Today, the six-mile-long TBI carries rainwater and snowmelt from city streets, parking lots and other hard surfaces to the Mississippi River. It is a “trunk conveyor” that receives runoff from the Cities of Saint Paul, Roseville, Falcon Heights and Maplewood as well as Ramsey County and Minnesota Department of Transportation.

CRWD makes regular inspections, minor maintenance and repairs to TBI. Over the years, this has included pipe and sewer repair, replacement and realignment. You can learn more about TBI repair projects in the link below.

MS4 Permit

TBI is considered a regulated municipal separate storm sewer system (MS4) that needs a stormwater discharge permit. CRWD must develop, implement and enforce a stormwater pollution prevention program (SWPPP) to control pollution and reduce peak flows so water quality throughout the District is protected.

The MS4 permit covers a five-year period. CRWD was first issued a permit from the state in 2006. A new general MS4 permit was issued to CRWD on April 3, 2014.

Stormwater Pollution Prevention Program (SWPPP)

As part of the MS4 permit, CRWD creates and follows a Stormwater Pollution Prevention Program (SWPPP) for TBI. This ensures that all District practices conform to required program elements, including minimum control measures for protecting water quality. CRWD conducts regular review of its best management practices (BMPs) as part of SWPPP reporting requirements.

Annual Report

Each year in June CRWD summarizes the previous year’s stormwater activities for the MS4 requirements, a draft report is available to the public and available for comments during this time. There is opportunity for residents and stakeholders to weigh in on the District’s stormwater management activities. The final MS4 Annual Report is included as an appendix in the District’s Annual Report, available as PDF documents on the About CRWD page.