HomeMy Public PortalAboutContechCDS_ApprovalLetter_020723Metropolitan
St. Louis Sewer
District
2350 Market Street
St. Louis, MO 63103-2555
(314) 768-6200
February 7, 2023
CONTECH Engineered Solutions, LLC
Mr. Chris Allen
1103 Schrock Rd, Ste 105
Columbus, OH 43229
RE: CONTECH Continuous Deflective Separator (CDS)
Highway Use Level (HUL) and Redevelopment Use Level (RUL)
Approval within the District
Dear Sir,
The Metropolitan St. Louis Sewer District (MSD) is providing HUL
and RUL approval for the use of the CONTECH CDS unit as a stand
alone water quality BMP, subject to the following provisions:
• The CDS is only approved for use on public highway and roadway
projects, and for redevelopment sites less than 5 acres. This
approval is based upon compliance with requirements listed in
MSD's Proprietary Water Quality Products and the MSD's
Stormwater Management Program (Revised Jan. 2009).
• The CDS must be sized such that the Maximum Treatment Flow
Rate (MTFR) for the unit exceeds the Water Quality flow rate
calculated for the unit's tributary area. The CDS's approved
MTFRs will be those shown in Table 1 below, to match the most
recently certified flow rates provided by the New Jersey
Department of Environmental Protection (NJDEP). Procedures
for calculating the Water Quality flow rate are provided in
Appendix D.10 of the Maryland Stormwater Design Manual
(2000).
Table 1: CDS Models and Approved MTFRs
Model Manhole
Diameter (ft)
MTFR (cfs)Treatment
Chamber Depth
(ft)
CDS-3 3 0.52 3.5
CDS-4 4 0.93 3.5
CDS-5 5 1.5 3.75
CDS-6 6 2.1 4.50
CDS-7 7 2.8 5.25
CDS-8 8 3.7 6.00
CDS-10 10 5.8 7.50
CDS-12 12 8.4 9.00
• The CDS will be configured as an off-line unit, downstream
from a diversion manhole. In most cases, the BMP will be
installed without the need to store the Water Quality volume
upstream of the unit.
• All devices shall provide a minimum sediment storage capacity
of 10 cubic feet.
• All proprietary lids and covers should be captive components.
The minimum size access hole is 30 inches in diameter.
• Confined space entry shall not be a requirement for routine
maintenance. No special tools or attachments should be
required to provide for routine maintenance with a vacuum
pumping truck.
• Project specific design calculations and maintenance plans
furnished by the manufacturer must be included within the
project's Stormwater Management Facilities Report prepared by
the consulting engineer.
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.
As of the date of this letter, the Downstream Defender's
certification status with NJDEP has expired. Should Hydro
International fail to be recertified with NJDEP before January 1,
2025, the Downstream Defender will be removed from MSD's list of
approved BMPs.
Sincerely,
Curtis Zurliene, PE
Civil Engineer (BMP Committee Chairman)
Engineering / Development Review
Metropolitan St. Louis Sewer District