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HomeMy Public PortalAboutFP_AppLetter_072122Metropolitan St. Louis Sewer District 2350 Market Street St. Louis, MO 63103-2555 (314)768-6200 July 21, 2022 Convergent Water Technologies Mr. Scott Gomeau 13810 Hollister Dr, Ste 100 Houston, TX 77086 RE: FocalPoint Biofiltration System Proprietary BMP Application Redevelopment Use Level (RUL) and Highway Use Level (HUE) within District Mr. Gomeau, The Metropolitan St. Louis Sewer District (MSD) has reviewed your application regarding the FocalPoint biofdtration system for use as a Best Management Practice (BMP) for stormwater management. MSD is pleased to provide RUL and HUL approval for the use of FocalPoint as a stand-alone water quality BMP, subject to the following provisions: • The FocalPoint biofdtration system is only approved for use on public highway and roadway projects, and for redevelopment sites less than 5 acres. This approval is based on compliance with requirements listed in MSD’s Proprietary Water Quality Products and the MSD’s Stormwater Management Program. • The FocalPoint system must be sized based on the New Jersey Department of Environmental Protection’s certified values. The system will be sized for Water Quality flowrate treatment using a Maximum Treatment Flow Rate (MTFR) of 1.6 gpm/ft2, or a filter bed area equal to 0.38% of the tributary area, whichever results in the larger size. Procedures for calculating the Water Quality treatment flowrate are provided in Appendix D.10 of the Maryland Stormwater Design Manual (2000). • MSD will not accept FocalPoint systems for public maintenance under any circumstance. • Project-specific design calculations and maintenance plans, furnished by the manufacturer, must be included with the project’s “Stormwater Management Facilities Report” prepared by the consulting engineer. • The FocalPoint system is not approved for Channel Protection (CPV) or flood protection (<2P2 & Qpioo) volume storage. • A pretreatment system, as recommended by the manufacturer, but subordinate to MSD’s standard pretreatment requirements, will be included, unless otherwise approved by MSD. • The initial installation of the FocalPoint system in the MSD shall include the following: 1) A manufacturer’s or vendor’s representative must be onsite during the proprietary BMP installation to ensure the product’s installation requirements are met. 2) Shop drawings indicating elevations of flow lines, weirs, pipe inverts, etc., will be required prior to installation. 3) The manufacturer or vendor must arrange for an as-built survey of the proprietary BMP to be performed by a Missouri-registered Professional Land Surveyor once the device has been installed. 4) The manufacturer or vendor must perform quarterly inspection of the proprietary BMP during its first year of operation, which will include visual inspections and qualitative analysis of the BMP’s sediment removal efficiency. MSD requests to be invited to these inspections to further enhance familiarity and understanding of the device. 5) Formal reports shall be submitted to MSD, including when the as-builts are completed and at each quarterly inspection. The reports shall include summaries, analysis mentioned in Item 4, photographs of the BMP and its appurtenances, and descriptions of the state of the BMP. The reports shall also evaluate the performance of the owner’s adherence to the approved maintenance program and offer suggestions for any areas of improvement. The FocalPoint biofiltration system is not approved for general use at this time. MSD reserves the ability to withdraw or modify this approval based on subsequent information, including information that this BMP does not satisfy MSD rules, requirements, or construction specifications. Sincerely, Curtis Zurliene, PE Civil Engineer (BMP Committee Chairman) Engineering Department / Development Review Metropolitan St. Louis Sewer District