Trout Brook Storm Sewer Interceptor

Capitol Region Watershed District (CRWD) owns, operates and maintains the Trout Brook Storm Sewer System, a “trunk conveyor” or interceptor storm sewer that receives runoff from the Cities of Saint Paul, Roseville, Falcon Heights and Maplewood as well as Ramsey County and Minnesota Department of Transportation. Trout Brook is considered a regulated municipal separate storm sewer system (MS4) that needs a stormwater discharge permit. As part of the permit, CRWD is required to develop, implement and enforce a stormwater pollution prevention program (SWPPP) to control pollution, reduce peak flows and increase groundwater recharge so water quality of local receiving waters is protected.

Background
The Trout Brook Storm Sewer was constructed between the 1880′s and 1950′s and served as a combined sanitary and storm sewer. In 1988 the combined system was separated and the Trout Brook Sanitary Interceptor was constructed nearly parallel to the old Trout Brook sewer to carry only wastewater to the Metropolitan Council Environmental Services Wastewater Treatment Plant. Upon completion, the old Trout Brook sewer remained as a storm sewer owned by the Metropolitan Council until it was transferred to Capitol Region Watershed District in 2006.

Description
Trout Brook is the largest subwatershed in CRWD, draining 5,054 acres from the cities of Roseville, Falcon Heights, Maplewood and Saint Paul and receiving water inputs from Como Lake and Lake McCarrons subwatersheds. The total stormwater drainage area for Trout Brook is nearly 8,000 acres. Land use in the subwatershed is a mix of residential, industrial and commercial uses with 42% impervious surfaces (i.e., roads, roofs, driveways, alleys and sidewalks).

The Trout Brook Storm Sewer consists of 6.5 miles of pipes and tunnels that have diameters of 6 to 13 feet. The Trout Brook Storm Sewer receives a majority of the runoff from the City of Saint Paul and it does not discharge directly to the Mississippi River; instead it connects to Saint Paul’s trunk sewer, which then discharges into the river just downstream of Lambert’s Landing.

Stormwater Discharge Permit
Upon acquisition of the Trout Brook storm sewer system, Capitol Region Watershed District was required to apply for a permit under federal Phase II Stormwater Rules for stormwater discharges from small MS4s located in urbanized areas. 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, Click here for a copy of CRWD’s reissued permit. For more information about the MS4 stormwater permitting program, visit EPA’s stormwater website or MN Pollution Control Agency’s stormwater website.

SWPPP
As part of the reissued permit application, CRWD has updated its Stormwater Pollution Prevention Program (SWPPP) to reduce the discharge of pollutants to the maximum extent practicable from the Trout Brook storm sewer, protect water quality of the Mississippi River, and meet requirements of the Clean Water Act. The SWPPP has six required program elements known as “minimum control measures.” The six minimum control measures are:
1) public education and outreach;
2) public involvement;
3) illicit discharge detection and elimination;
4) construction site stormwater controls;
5) post-construction stormwater management; and
6) pollution prevention/good housekeeping for municipal operations.

To meet the goals of each minimum control measure, CRWD is required to design and implement best management practices (BMPs) as part of the SWPPP. All CRWD SWPPP reports can be viewed by visiting our CRWD Reports Page.

Annual Report
By the end of June each year, CRWD prepares a summary report of stormwater management activities from the previous year and identifies any changes to the SWPPP. The report is presented to the public each spring for their own information and for providing input into CRWD’s Stormwater Program. CRWD reviews public comments and makes appropriate revisions to the SWPPP. CRWD Annual Reports can be viewed by visiting our CRWD Reports Page.

CRWD is also required to submit an Annual Report of work to the Minnesota Board of Water and Soil Resources (BWSR). Click here to view our final 2014 Annual Report for BWSR.

If you need more information or have questions, please contact Anna Eleria, Water Resource Project Manager.

Education and Outreach on Stormwater BMPs
Public education and outreach is a key component to better stormwater management because polluted stormwater runoff originates from various activities and sources. CRWD has created several educational materials as well as gathered a list of links to other resources for several of the minimum control measures.

Click one of the links below for information.

Updated CRWD Rules
Regulatory control of stormwater runoff including erosion and sediment control, post-construction stormwater management and illicit discharges and connections

Illicit Discharge Detection and Elimination
– IDDE Guidance Manual

Construction Site Stormwater Runoff Control
– MN Stormwater Manual
– Fact Sheet for Homeowners

Post-Construction Stormwater Management
– MN Stormwater Manual
– Protecting Water Quality in Urban Areas Manual
– Low Impact Development

Stormwater Monitoring
Since 2006, CRWD has been monitoring the water quality and volume of stormwater at the west and east branches and outlet of the storm sewer system. CRWD also monitors four stormwater ponds located in the subwatershed: 1) Arlington-Jackson; 2) Sims-Agate; 3) Westminster-Mississippi; and 4) Willow Reserve. Monitoring results show that phosphorus, sediments, bacteria, lead and copper are the pollutants of most concern. For more information about stormwater monitoring results, click here to view map of monitoring sites and/or read the annual monitoring reports.