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389023swi r--1 • Metropolitan St. Louis Sewer District 2350 Market Street St. Louis, MO 63103-2555 (314) 768-6200 November 3, 2010 Ben Burkhart StormTrap 2495 W. Bungalow Rd. Morris IL 60450 RE: StormTrap® Detention System Provisional Use Level (PUL) Approval within District Dear Sir: The Metropolitan St. Louis Sewer District (MSD) has reviewed your application regarding the StormTrap® Stormwater Detention System for use as a stormwater 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 StormTrap® Detention System for use as a stormwater storage system. • The StormTrap® Detention System is approved for use on new and redevelopment projects of any size. A total of three (3) installations shall be allowed under this approval. • The StormTrap® Detention System shall be used only to provide storage for the Water Quality Design Storm, (WQv) Peak Design Storm (Qp) and Channel Protection (CPv) design storm volumes. • The StormTrap® Detention System is not intended to be a device that is used as a stand alone BMP. • Consistent with MSD Rules and Regulations, the use of buried storage shall be avoided on residential type projects. • 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. Minimum access diameter is thirty (30) inches. • A concrete bottom is required. • Ability to handle an HS-20 loading is required. • Approved flexible seals (A-loks or Z-loks) shall be utilized on all pipe connections. Perpendicular pipe connections will be required. • Project specific design calculations and maintenance plans furnished by StormTrap® 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 "StormTrap® Submittal to Metropolitan St. Louis Sewer District Version 1.0," October 2009. • The first three installations of the StormTrap® System in the MSD service area 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 and as -built drawings 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 four (4) inspections of each proprietary device during its' first two (2) years 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) Formal reports shall be submitted to MSD, including as-builts and at each bi- annual 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. 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. Sincerely, Jason Peterein, P.E. Civil Engineer (BMP Committee Chairman) Engineering/Design Metropolitan St. Louis Sewer District