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