HomeMy Public PortalAbout366311Metropolitan
St. Louis Sewer
District
2350 Market Street
St. Louis, MO 63103-2555
(314) 768-6200
June 29, 2010
Mr. John MacKinnon, P.E.
Regulatory Specialist
Hydro International
94 Hutchins Drive
Portland, ME 04102
RE: Stoinibloc Stormwater Storage & Infiltration System
Provisional Use Level (PUL) Approval within District
Dear Sir:
The Metropolitan St. Louis Sewer District (MSD) has reviewed your application regarding the
Stormbloc Stotinwater Storage & Infiltration System for use as a stonnwater storage system; that is
with the intent to provide detention and attenuation of peak flows. MSD is pleased to provide
Provisional Use Level (PUL) approval for use of the Stormbloc Stormwater Storage & Infiltration
System for use as a stointwater storage system.
o The Stormbloc Stoiiiiwater Storage & Infiltration System is only approved for use on
redevelopment projects of any size. A total of only one (1) installation shall be allowed
under this approval.
The Stormbloc Stormwater Storage & Infiltration System shall be used only to provide
storage for the Peak Design Stottn (Qp) and Channel Protection (CPv) design storm
volumes.
o The Stormbloc Stoiniwater Storage & Infiltration System is not intended to be a device that
is used as a stand alone BMP.
o The Stotinbloc Stormwater Storage & Infiltration System may be used beneath pervious
and impervious paving systems, or as part of an infiltration system.
• Consistent with MSD Rules and Regulations, the use of buried storage shall be avoided on
residential type projects.
• Adequate pretreatment shall be provided in all site designs, this will include a stand-alone
BMP capable of treating the full Water Quality (WQv) volume.
• Devices should be kept off-line until the construction site is stabilized and otherwise
protected from sediment build-up during and after construction.
• Adequate access and inspection access shall be provided.
• All proprietary lids and covers should be captive components.
• Project specific design calculations and maintenance plans furnished by Hydro International
must be included within the project's "Stormwater Management Facilities Report" prepared
by the consulting engineer. All applicable elements of the design shall comply with the
"Stoinibloc Submittal to Metropolitian St. Louis Sewer District Version 1.0," October
2009.
The initial installation of the Stoinibloc Stoiniwater Storage & Infiltration System in the
MSD shall include the following:
1) A manufacturer's or vendor's representative must be onsite during the installation to
ensure the product's installation requirements are met.
2) Shop drawings indicating elevations of flowlines, pipe inverts, etc. will be required
prior to installation.
3) The manufacturer or vendor must arrange for an as -built survey of the proprietary
storage device to be performed by a Missouri -registered Professional Land Surveyor
once the device has been installed, and prior to any testing or monitoring.
4) The manufacturer or vendor must perform quarterly inspections of the proprietary
device during its' first year of operation, which will include visual inspections. MSD
requests to be invited to these inspections to further enhance familiarity and
understanding of the device.
5) Foimal reports shall be submitted to MSD, including as-builts and at each quarterly
inspection. The reports shall include summaries, quantitative analysis mentioned in
item 4, photographs of the structure, inlet, internal conditions of the structure, and
outfall conditions, etc. 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 Stormbloc Stormwater Storage & Infiltration 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 indicating that this BMP does not satisfy MSD rules, requirements, or
construction specifications. This approval shall be for a period of two (2) years from the date of this
letter.
Sincerely,
f3
Michael T. Buechter, P.E.
Principal Engineer (BMP Committee Chainiian)
Engineering/Design
Metropolitan St. Louis Sewer District