Previous Lake McCarrons water quality studies revealed that despite phosphorus reduction efforts, the contributing watershed continues to be a major source of nutrients. SRF was retained by the Capitol Region Watershed District (CRWD) to study the Lake McCarrons watershed and the Parkview Center School location and recommend locations and treatment measures, with the focus on removing phosphorous. Many options were considered but challenges with poor soils, topography and site limitations almost ruled out any potential treatment at this site. However, Roseville Area Schools had a project at a nearby property with excess fill material and mentioned that they wanted to place it on the Parkview site for future expansion of the parking lot. The location under a future parking lot was suitable for a detention and filter cartridge vault. The contributing watershed that drains to County Road B adjacent to the Parkview Center School property has an area of 44.2 acres of residential and institutional property. This project is estimated to remove 45 pounds of Total Phosphorous (TP) from entering Lake McCarrons.
CRWD obtained a grant to construct the project and retained SRF to do the final design. The use of filter cartridge vaults is relatively new and has shown to be an effective way to remove Soluble Phosphorous from stormwater runoff. The design consisted of geotechnical and surcharge analysis, storm sewer diversion, CMP storage facility, filter cartridge vault selection and design, analysis for future water reuse connections, and maintenance considerations. Other design elements included traffic control, electrical access, right-of-way documentation, rendering development and educational signing used on-site and on-lineThe project also included stakeholder facilitation with CRWD, Roseville Area Schools, Ramsey County and City of Roseville.