HomeMy Public PortalAboutP001174320_3/13/2024 5:51:30 PMPost-Construction Stormwater BMP Inspection and Maintenance Record
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West
Chesterfield, MO 63017
Customer:Bayer
Contact:Anna Tang
Phone Number:314-694-3169
Email:anna.tang@bayer.com Inspector(s):Marianne Pott
Company:Stormwater STL LLC
Address:6514 Lansdowne Avenue 63109
Record Start Date:March 28, 2011 Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
BIOR BIORETENTION/RAINGARDEN (A)P-1 MICROPOOL EXTENDED DETENTION POND (A)
BIOS BIORETENTION/RAINGARDEN (SMALL) (A)P-2 WET POND (A)
GRWD GRAVEL WETLAND (A)P-3 WET EXTENDED DETENTION POND (A)
CIST CISTERN/DRYWELL (U)P-5 POCKET POND (A)
O-1 DRY SWALE - LARGE (A)W-2 ED SHALLOW WETLAND (A)
O-2 DRY SWALE - SMALL (A)W-3 POND/WETLAND SYSTEM (A)
O-3 WET SWALE - LARGE (A)SCDN STORM CREDIT - DISCONNECT NONROOFTOP (A)
O-4 WET SWALE - SMALL (A)SCDR STORM CREDIT - DISCONNECT ROOFTOP (A)
1 HDSP PROPRIETARY HYDRODYNAMIC SEPARATOR SCES STORM CREDIT - ENVIRONMENTALLY SENSTV(A)
I-1 INFILTRATION TRENCH (A)SCNA STORM CREDIT - NATURAL AREA CONSERVA (A)
I-2 INFILTRATION BASIN (A)SCOC STORM CREDIT - OPEN CHANNEL USE (A)
AMDS AMENDED SOILS (A)SCSB STORM CREDIT - SHEET FLOW TO BUFFER (A)
GRRF GREEN ROOF (A)F-1 SURFACE SAND FILTER (A)
O-5 FILTER STRIPS - LARGE (A)F-3 PERIMETER SAND FILTER (A)
O-6 FILTER STRIPS - SMALL (A)F-4 ORGANIC FILTER (A)
PPAS PERMEABLE PAVEMENT - ASPHALT (A)F-5 POCKET SAND FILTER (A)
PPBK PERMEABLE PAVEMENT - PAVER BLOCK (A)1 F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
DET DETENTION 1 WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2011.03.28 Inspection 2018.09.10 Inspection
2012.08.21 One-inch rainfall inspection by CBRE 2018.12.11 Inspection
2012.09.04 One-inch rainfall inspection by CBRE 2019.03.11 Inspection
2012.09.10 One-inch rainfall inspection by CBRE 2019.05.14 Maintenance on StormFilter Vault
2012.11.12 One-inch rainfall inspection by CBRE 2019.06.13 Inspection
2013.01.28 One-inch rainfall inspection by CBRE 2019.06.11 Maintenance on Stormtech System
2013.03.13 One-inch rainfall inspection by CBRE 2019.07.02 Maintenance on Stormtech System
2013.03.21 Inspection by Stormwater STL 2019.09.17 Inspection
2013.03.31 2012 Annual Report submission to MSD 2019.12.11 Inspection
2014.03.28 Inspection 2020.03.05 Inspection
2014.03.29 2013 Annual Report submission to MSD 2020.06.23 Inspection
2014.12.08 Inspection 2020.09.16 Inspection
2015.03.11 Inspection 2020.12.08 Inspection
2015.03.23 2014 Annual Report submission to MSD 2021.03.19 Inspection
2015.05.14 Replaced top and vacuumed HDS 2021.06.08 Inspection
2015.06.11 Restored site using GrowSoxx to build a retaining wall 2021.06.17 Maintenance Filters & Duramax Pipe
2015.06.11 Inspection 2021.09.08 Inspection
2015.06.11 Completed restoration of area around HDS 2021.12.07 Inspection
2015.09.10 Inspection 2022.03.02 Inspection
2015.10.12 Maintenance - Cleaned Inlets & Installed FlexStorm Inserts 2022.06.22 Inspection
2015.10.13 2022.09.22 Inspection
2015.10.14 2022.12.07 Inspection
2015.10.15 Maintenance on StormFilter Vault 2023.03.07 Inspection
2015.12.09 Inspection 2023.06.07 Inspection
2016.02.23 Inspection 2023.09.20 Inspection
2016.06.20 Inspection 2023.12.06 Inspection
2016.09.14 Inspection
2016.09.21 Maintenance on HDS Unit & StormFilter Vault
2016.12.06 Inspection
2017.02.22 Maintenance on DuroMaxx WQ Storage
2017.03.02 Inspection
2017.06.19 Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
(See Next Column)
Maintenance on HDS Unit & DuroMaxx WQ Storage
Maintenance on DuroMaxx WQ Storage
4
Bayer Equip #:
Post-Construction Stormwater BMP Inspection Report
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West 63017
Inspection Date:December 6, 2023
Time:9:30 AM
Weather:39°F; Sunny
Last rain event:0.01" on December 5, 2023
Last one inch rainfall:1.62" on September 27, 2023
Bayer Inspector(s):Marianne Pott
Anna Tang Company:Stormwater STL LLC
314-694-3169 Address:6514 Lansdowne Avenue 63109
anna.tang@bayer.com Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Last Inspection Date:September 20, 2023
Inspector's Summary:
Status of Open Action Items Identified During This Reporting Year:
Grate Inlet with Side Intake HR-7
Access Points to Haul Road Inspection
Action Items Identified During This Inspection:
No new action items were identified during this inspection.
Page 1
This document has been prepared exclusively for the Customer noted above (Customer) by Stormwater STL LLC (Stormwater STL), based on a visual inspection conducted on the date(s) noted
above. Unless specifically indicated, Stormwater STL did not undertake any forensic investigation at this location on the date(s) noted. The opinions expressed in this document relate only to the
condition of the site and the Post-Construction Stormwater BMP(s) as observed by Stormwater STL on the date(s) noted. The content of this document reflects the opinion of Stormwater STL only
and Stormwater STL makes no express or implied representation or warranty with respect to the conditions described or the functionality of the systems identified in this report. Other than Customer,
third parties who rely upon this document do so solely at their own risk and Stormwater STL disclaims all liability, damages or loss with respect to such reliance. Neither Customer nor Stormwater
STL, nor any person acting for and/or on behalf of those companies, assumes any responsibility, duty of care or liability to any person to update the contents of this document or to distribute any
subsequently learned information to recipients of this document other than to Customer. This disclaimer must accompany every copy of this document, which is an integral document and must be
read in its entirety.
Construction for this project was approved by MSD on October 14, 2010. Stormwater BMPs associated with this system include a Contech
Hydrodynamic Separator, a 72" DuroMaxx Water Quality Storage, a Contech StormFilter Vault, StormTech Chambers, and associated
private inlets, manholes, and piping. Grate Inlets along Haul Road accumulate excessive sediment and were therefore modified in October
2015 with the installation of 16 flex storm grate inlet filter inserts. Despite these modifications, maintenance to remove sediment from the
system has been required every few years, most recently June 2021 with servicing the StormFilter Vault and the west DuroMaxx pipe. After
carefully reviewing each component of the system and finding only one small maintenance item to be addressed, I am pleased to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent.
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer) --- COMPLETED / ONGOINGGrate Inlets with Side Intakes along Haul Road
Phone Number:
Email:
CLEAR brush around all manholes prior to inspections (Bayer) --- COMPLETED / ONGOING
REPLACE Flexstorm filter insert in Grate Inlet HR-7 (Bayer) --- NOT COMPLETED
Bayer Equip #:
Customer:
Contact:
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Comments
Access
Clogging
Water ponding on surface
Sheen on water surface
Odor
Sediment
Mulch na
Turf na
Weeds na
Underdrain na
Structural components
14'-6.5"
15'-8"
1'-1.5"
2'-0"
72" DuroMaxx Water Quality Storage (GIS-BMP-6384)
Comments
Access
Trash/debris
Sediment buildup in east/uphill pipe
Sediment buildup in west/downhill pipe
Water ponding on bottom
Structural components
Comments
Access
Water ponding on surface
Sheen on water surface na
Odor
Erosion na
Mulch na
Turf na
Plants na
Weeds na
Underdrain
Structural components
1/8" avg
Underground StormTech Detention with MC-3500 Chambers (GIS-BMP-5805)
Comments
Access
Trash/debris
Estimated sediment buildup from MH HR-1
Measured sediment buildup from inspection port
Water ponding on bottom
Structural components Maintenance was conducted in July 2019
Private Inlets/Manholes/Piping
Comments
Miscellaneous
Comments
Page 2Bayer Haul Road System - December 6, 2023
Mosquitoes
Encroachment(s) on facility or easement
Pretreatment - Contech VortSentry HS72 Hydrodynamic Separator in MH HS 2B (GIS-BMP-6380)
REPLACE Flexstorm filter insert in Grate Inlet HR-7, photo 12 (Bayer)
Condition of filter media
Max. sediment depth recommended by manufacturer =
Access
Sediment
Sediment coating 4 cartridge tops along west perimeter; could be up to 0.25"
No indications of clogging
Filter fabric visible in front 33% of row; sediment collecting in back 67%, photo 9 & 10
Sediment visible in channels of MH HR-1
No sheen visible on water surface
Vegetation around manholes was cut down and removed
Decrease of 0.5" since September 2023 inspection
Trash/debris
Other (describe) (Haul Road Surface)
None
Depth of sediment =
HDS unit is at 56.25% of capacity, photo 1
Contech StormFilter Stormwater Quality System in MH 2G with 12 Cartridges (GIS-BMP-6385)
Trash/debris
No vertical access to underdrain manifold; float valves appear functional
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer)
No erosion or settlement noted
Clear, photo 11
Erosion/settlement around structures
Estimated 1.5" of sediment and rock visible below north manhole, photo 2
Complaints None of which I'm aware
Top 4" of filter media remains porous, below 4" is filling in with sediment, photos 7 & 8
No ponding water in isolator row
Depth of silt on filter cartridge tops
Clogging
Depth of sediment on vault floor
Sediment was removed and 12 filter cartridges were replaced in June 2021
No ponding water
System discharge
Trash/debris - Grated Curb Inlets
Erosion
Up to 3" of sediment and leaves near outflow module & below ladder, photo 6
No odor
Some leaves collecting in StormFilter vault
0.125 - 0.5" of sediment on walls; 0.75 - 1" on bottom with 2 - 2.5" in low spots, photo 3
Sediment measured as 0.75" below inspection port
HDS unit was last maintained on 9/21/2016
Distance from rim to sediment =
Distance from rim to bottom =
None
Post-Construction Stormwater BMP Inspection Report
Photographs
See attached sheet
Inspector's Notes
Page 3Bayer Haul Road System - December 6, 2023
March 11, 2019: Maintenance for open action items has been approved and will be scheduled once the weather cooperates. Due to the weight of the
commercial vacuum truck, the ground surrounding the system needs to be dry and stable --- conditions that have been hard to come by with this wet
winter.
June 13, 2019: Maintenance was completed on the StormFilter vault but the weather, etc. has not yet allowed for maintenance of the isolator row. No
increase of sediment was measured in the HDS unit. Filter media in the StormFilter vault remains in original condition with no visible signs of sediment
accumulation. A very minor amount of sediment was noted on the vault floor and tops of the cartridges.
September 17, 2019: All maintenance items were completed and each BMP remains in good condition. Locust saplings from brush control efforts along
the road above the system were cut and dumped down the hill, where we found heavy brush covering manholes. For future summer inspections, it would
be helpful to maintain a few feet of brush clearance around the manholes access for the inspection.
December 11, 2019: A slight increase of sediment was measured in the HDS unit. Sediment in the other treatment and storage components remains
stable. The filter inserts in the grate inlets along Haul Road should continue to be emptied on a periodic basis. They each contained a few inches of
sediment, leaves and debris. This is more than in previous visits but far from being at capacity. The one in Grate Inlet with Side Intake HR-12, at the top
of the road on the south side, contains lots of gravel and rock from the construction area.
March 5, 2020: Slight increase of sediment was measured in the HDS unit and on the StormFilter vault floor. The filter inserts in the grate inlets along
Haul Road contained only a very small amount of sediment - evidence that they are being serviced periodically.
June 23, 2020: Sediment appears to have migrated south down the west DuroMaxx pipe towards the StormFilter vault. Filter media is mostly discolored
by sediment now but remains porous. The floor of the vault contains no more than 2" of sediment at the deepest. Over 4" of sediment on the floor is the
threshold at which maintenance is needed. A dusting of sediment is now visible on the isolator, but not deep enough to be measured. All filter inserts in
the grate inlets along Haul Road show signs of being emptied periodically.
September 16, 2020: Major rain events in July and August appear to have filled in the StormFilter Vault. While there is still some porosity left in the filter
media itself, the sediment on the tops of the cartridges and the floor of the vault have met the criteria for when maintenance is due. Maintenance is
recommended to remove up to 5" of sediment from the west DuroMaxx pipe (the east is mostly clean) and to remove sediment and replace filter media
cartridges in the StormFilter vault.
December 8, 2020: The HDS unit continues to add only 0.5 inches of sediment on a quarterly basis. Flexstorm filter inserts in grate inlets along Haul
Road continue to be maintained.
March 19, 2021: Purchase orders have been generated to provide the needed maintenance on the StormFilter Vault and the West DuroMaxx pipe. All
maintenance will be scheduled when weather is appropriate for the commercial vacuum truck to access the site without issue. Previous experience has
shown that the ground needs to be adequately dried out or else the truck can get stuck, which might not be until the summer. All FlexStorm inlet inserts
are receiving frequent maintenance to remove sediment that has been captured.
June 8, 2021: Maintenance is tentatively planned for June 17 & 18th. We spoke with Munie about trimming vegetation back from all manholes and
structural components of the system so that maintenance and inspections can occur without interference. As infiltration through the StormFilter system
slows, sediment continues to collect in the DuroMaxx system. In previous visits, no sediment was visible at the south end of the east pipe. Now about 0.5"
of sediment is visible at the south end, increasing up to about 2" on the sides at the north end.
September 8, 2021: Maintenance on the west DuroMaxx pipe and StormFilter was completed in June 2021. Some sediment is already collecting in these
structures, including up to 0.25" on the sides of the pipe and up to 1.5" on the StormFilter vault floor and about four of the cartridge tops.
December 7, 2021: All parts of the system appear to remain in good condition.
March 2, 2022: Sediment continues to increase in all parts of the system but no maintenance is needed.
June 22, 2022: A decrease of sediment was measured in the HDS unit. No significant changes were noted in any of the other components.
September 22, 2022: An increase of 1.5 inches of sediment was measured in the HDS unit. Sediment has continued to increase in the StormFilter vault,
now showing up to 3 inches at the west perimeter around the outlet module and around 2 cartridges.
December 7, 2022: Sediment continues to increase in the StormFilter vault, HDS unit and StormTech isolator row.
March 7, 2023: HDS unit added 3 inches of sediment and is now just over 70% of capacity. At this rate, it will likely need to be cleaned in quarter 4 2023
or quarter 1 2024. One Flexstorm filter insert looks to be torn right at the side intake expansion of the filter insert. The filter should be replaced.
June 7, 2023: Sediment in the HDS unit decreased by 1.5 inches.
September 20, 2023: The cap was removed from the inspection port during the last inspection so it could dewater. Sediment below the inspection port
was measured at 0.75 inches.
December 6, 2023: Leaves and sediment continue to collect in Flexstorm filter inserts - maintenance should be completed before the next quarterly
inspection. Sediment in the HDS unit seemed to decrease slightly, but continues to slowly increase in the StormFilter unit.
BAYER –
Haul Road Stormwater BMP Photos
December 6, 2023
1. HDS UNIT IS AT 56.25% OF
CAPACITY (GIS-BMP-6380)
2. VIEW OF EAST DUROMAXX
PIPE (GIS-BMP-6384)
3. VIEW OF WEST DUROMAXX
PIPE (GIS-BMP-6384)
4. VIEW INTO STORMFILTER
VAULT (GIS-BMP-6385)
5. MINIMAL SEDIMENT AT
MIDDLE OF STORMFILTER VAULT
6. UP TO 3” OF SEDIMENT AT
WEST PART OF VAULT
7. FILTER MEDIA REMAINS IN
GOOD CONDITION
8. FILTER MEDIA REMAINS IN
DECENT CONDITION
9. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
10. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
11. VIEW OF CS HR 19 SHOWING
CONTROL STRUCTURE IS CLEAR
12. REPLACE FLEXSTORM FILTER
INSERT IN GRATE INLET HR-7
Post-Construction Stormwater BMP Inspection and Maintenance Record
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West
Chesterfield, MO 63017
Customer:Bayer
Contact:Anna Tang
Phone Number:314-694-3169
Email:anna.tang@bayer.com Inspector(s):Marianne Pott
Company:Stormwater STL LLC
Address:6514 Lansdowne Avenue 63109
Record Start Date:March 28, 2011 Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
BIOR BIORETENTION/RAINGARDEN (A)P-1 MICROPOOL EXTENDED DETENTION POND (A)
BIOS BIORETENTION/RAINGARDEN (SMALL) (A)P-2 WET POND (A)
GRWD GRAVEL WETLAND (A)P-3 WET EXTENDED DETENTION POND (A)
CIST CISTERN/DRYWELL (U)P-5 POCKET POND (A)
O-1 DRY SWALE - LARGE (A)W-2 ED SHALLOW WETLAND (A)
O-2 DRY SWALE - SMALL (A)W-3 POND/WETLAND SYSTEM (A)
O-3 WET SWALE - LARGE (A)SCDN STORM CREDIT - DISCONNECT NONROOFTOP (A)
O-4 WET SWALE - SMALL (A)SCDR STORM CREDIT - DISCONNECT ROOFTOP (A)
1 HDSP PROPRIETARY HYDRODYNAMIC SEPARATOR SCES STORM CREDIT - ENVIRONMENTALLY SENSTV(A)
I-1 INFILTRATION TRENCH (A)SCNA STORM CREDIT - NATURAL AREA CONSERVA (A)
I-2 INFILTRATION BASIN (A)SCOC STORM CREDIT - OPEN CHANNEL USE (A)
AMDS AMENDED SOILS (A)SCSB STORM CREDIT - SHEET FLOW TO BUFFER (A)
GRRF GREEN ROOF (A)F-1 SURFACE SAND FILTER (A)
O-5 FILTER STRIPS - LARGE (A)F-3 PERIMETER SAND FILTER (A)
O-6 FILTER STRIPS - SMALL (A)F-4 ORGANIC FILTER (A)
PPAS PERMEABLE PAVEMENT - ASPHALT (A)F-5 POCKET SAND FILTER (A)
PPBK PERMEABLE PAVEMENT - PAVER BLOCK (A)1 F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
DET DETENTION 1 WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2011.03.28 Inspection 2018.09.10 Inspection
2012.08.21 One-inch rainfall inspection by CBRE 2018.12.11 Inspection
2012.09.04 One-inch rainfall inspection by CBRE 2019.03.11 Inspection
2012.09.10 One-inch rainfall inspection by CBRE 2019.05.14 Maintenance on StormFilter Vault
2012.11.12 One-inch rainfall inspection by CBRE 2019.06.13 Inspection
2013.01.28 One-inch rainfall inspection by CBRE 2019.06.11 Maintenance on Stormtech System
2013.03.13 One-inch rainfall inspection by CBRE 2019.07.02 Maintenance on Stormtech System
2013.03.21 Inspection by Stormwater STL 2019.09.17 Inspection
2013.03.31 2012 Annual Report submission to MSD 2019.12.11 Inspection
2014.03.28 Inspection 2020.03.05 Inspection
2014.03.29 2013 Annual Report submission to MSD 2020.06.23 Inspection
2014.12.08 Inspection 2020.09.16 Inspection
2015.03.11 Inspection 2020.12.08 Inspection
2015.03.23 2014 Annual Report submission to MSD 2021.03.19 Inspection
2015.05.14 Replaced top and vacuumed HDS 2021.06.08 Inspection
2015.06.11 Restored site using GrowSoxx to build a retaining wall 2021.06.17 Maintenance Filters & Duramax Pipe
2015.06.11 Inspection 2021.09.08 Inspection
2015.06.11 Completed restoration of area around HDS 2021.12.07 Inspection
2015.09.10 Inspection 2022.03.02 Inspection
2015.10.12 Maintenance - Cleaned Inlets & Installed FlexStorm Inserts 2022.06.22 Inspection
2015.10.13 2022.09.22 Inspection
2015.10.14 2022.12.07 Inspection
2015.10.15 Maintenance on StormFilter Vault 2023.03.07 Inspection
2015.12.09 Inspection 2023.06.07 Inspection
2016.02.23 Inspection 2023.09.20 Inspection
2016.06.20 Inspection 2023.12.06 Inspection
2016.09.14 Inspection
2016.09.21 Maintenance on HDS Unit & StormFilter Vault
2016.12.06 Inspection
2017.02.22 Maintenance on DuroMaxx WQ Storage
2017.03.02 Inspection
2017.06.19 Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
(See Next Column)
Maintenance on HDS Unit & DuroMaxx WQ Storage
Maintenance on DuroMaxx WQ Storage
4
Bayer Equip #:
Post-Construction Stormwater BMP Inspection Report
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West 63017
Inspection Date:December 6, 2023
Time:9:30 AM
Weather:39°F; Sunny
Last rain event:0.01" on December 5, 2023
Last one inch rainfall:1.62" on September 27, 2023
Bayer Inspector(s):Marianne Pott
Anna Tang Company:Stormwater STL LLC
314-694-3169 Address:6514 Lansdowne Avenue 63109
anna.tang@bayer.com Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Last Inspection Date:September 20, 2023
Inspector's Summary:
Status of Open Action Items Identified During This Reporting Year:
Grate Inlet with Side Intake HR-7
Access Points to Haul Road Inspection
Action Items Identified During This Inspection:
No new action items were identified during this inspection.
Page 1
This document has been prepared exclusively for the Customer noted above (Customer) by Stormwater STL LLC (Stormwater STL), based on a visual inspection conducted on the date(s) noted
above. Unless specifically indicated, Stormwater STL did not undertake any forensic investigation at this location on the date(s) noted. The opinions expressed in this document relate only to the
condition of the site and the Post-Construction Stormwater BMP(s) as observed by Stormwater STL on the date(s) noted. The content of this document reflects the opinion of Stormwater STL only
and Stormwater STL makes no express or implied representation or warranty with respect to the conditions described or the functionality of the systems identified in this report. Other than Customer,
third parties who rely upon this document do so solely at their own risk and Stormwater STL disclaims all liability, damages or loss with respect to such reliance. Neither Customer nor Stormwater
STL, nor any person acting for and/or on behalf of those companies, assumes any responsibility, duty of care or liability to any person to update the contents of this document or to distribute any
subsequently learned information to recipients of this document other than to Customer. This disclaimer must accompany every copy of this document, which is an integral document and must be
read in its entirety.
Construction for this project was approved by MSD on October 14, 2010. Stormwater BMPs associated with this system include a Contech
Hydrodynamic Separator, a 72" DuroMaxx Water Quality Storage, a Contech StormFilter Vault, StormTech Chambers, and associated
private inlets, manholes, and piping. Grate Inlets along Haul Road accumulate excessive sediment and were therefore modified in October
2015 with the installation of 16 flex storm grate inlet filter inserts. Despite these modifications, maintenance to remove sediment from the
system has been required every few years, most recently June 2021 with servicing the StormFilter Vault and the west DuroMaxx pipe. After
carefully reviewing each component of the system and finding only one small maintenance item to be addressed, I am pleased to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent.
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer) --- COMPLETED / ONGOINGGrate Inlets with Side Intakes along Haul Road
Phone Number:
Email:
CLEAR brush around all manholes prior to inspections (Bayer) --- COMPLETED / ONGOING
REPLACE Flexstorm filter insert in Grate Inlet HR-7 (Bayer) --- NOT COMPLETED
Bayer Equip #:
Customer:
Contact:
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Comments
Access
Clogging
Water ponding on surface
Sheen on water surface
Odor
Sediment
Mulch na
Turf na
Weeds na
Underdrain na
Structural components
14'-6.5"
15'-8"
1'-1.5"
2'-0"
72" DuroMaxx Water Quality Storage (GIS-BMP-6384)
Comments
Access
Trash/debris
Sediment buildup in east/uphill pipe
Sediment buildup in west/downhill pipe
Water ponding on bottom
Structural components
Comments
Access
Water ponding on surface
Sheen on water surface na
Odor
Erosion na
Mulch na
Turf na
Plants na
Weeds na
Underdrain
Structural components
1/8" avg
Underground StormTech Detention with MC-3500 Chambers (GIS-BMP-5805)
Comments
Access
Trash/debris
Estimated sediment buildup from MH HR-1
Measured sediment buildup from inspection port
Water ponding on bottom
Structural components Maintenance was conducted in July 2019
Private Inlets/Manholes/Piping
Comments
Miscellaneous
Comments
Page 2Bayer Haul Road System - December 6, 2023
Mosquitoes
Encroachment(s) on facility or easement
Pretreatment - Contech VortSentry HS72 Hydrodynamic Separator in MH HS 2B (GIS-BMP-6380)
REPLACE Flexstorm filter insert in Grate Inlet HR-7, photo 12 (Bayer)
Condition of filter media
Max. sediment depth recommended by manufacturer =
Access
Sediment
Sediment coating 4 cartridge tops along west perimeter; could be up to 0.25"
No indications of clogging
Filter fabric visible in front 33% of row; sediment collecting in back 67%, photo 9 & 10
Sediment visible in channels of MH HR-1
No sheen visible on water surface
Vegetation around manholes was cut down and removed
Decrease of 0.5" since September 2023 inspection
Trash/debris
Other (describe) (Haul Road Surface)
None
Depth of sediment =
HDS unit is at 56.25% of capacity, photo 1
Contech StormFilter Stormwater Quality System in MH 2G with 12 Cartridges (GIS-BMP-6385)
Trash/debris
No vertical access to underdrain manifold; float valves appear functional
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer)
No erosion or settlement noted
Clear, photo 11
Erosion/settlement around structures
Estimated 1.5" of sediment and rock visible below north manhole, photo 2
Complaints None of which I'm aware
Top 4" of filter media remains porous, below 4" is filling in with sediment, photos 7 & 8
No ponding water in isolator row
Depth of silt on filter cartridge tops
Clogging
Depth of sediment on vault floor
Sediment was removed and 12 filter cartridges were replaced in June 2021
No ponding water
System discharge
Trash/debris - Grated Curb Inlets
Erosion
Up to 3" of sediment and leaves near outflow module & below ladder, photo 6
No odor
Some leaves collecting in StormFilter vault
0.125 - 0.5" of sediment on walls; 0.75 - 1" on bottom with 2 - 2.5" in low spots, photo 3
Sediment measured as 0.75" below inspection port
HDS unit was last maintained on 9/21/2016
Distance from rim to sediment =
Distance from rim to bottom =
None
Post-Construction Stormwater BMP Inspection Report
Photographs
See attached sheet
Inspector's Notes
Page 3Bayer Haul Road System - December 6, 2023
March 11, 2019: Maintenance for open action items has been approved and will be scheduled once the weather cooperates. Due to the weight of the
commercial vacuum truck, the ground surrounding the system needs to be dry and stable --- conditions that have been hard to come by with this wet
winter.
June 13, 2019: Maintenance was completed on the StormFilter vault but the weather, etc. has not yet allowed for maintenance of the isolator row. No
increase of sediment was measured in the HDS unit. Filter media in the StormFilter vault remains in original condition with no visible signs of sediment
accumulation. A very minor amount of sediment was noted on the vault floor and tops of the cartridges.
September 17, 2019: All maintenance items were completed and each BMP remains in good condition. Locust saplings from brush control efforts along
the road above the system were cut and dumped down the hill, where we found heavy brush covering manholes. For future summer inspections, it would
be helpful to maintain a few feet of brush clearance around the manholes access for the inspection.
December 11, 2019: A slight increase of sediment was measured in the HDS unit. Sediment in the other treatment and storage components remains
stable. The filter inserts in the grate inlets along Haul Road should continue to be emptied on a periodic basis. They each contained a few inches of
sediment, leaves and debris. This is more than in previous visits but far from being at capacity. The one in Grate Inlet with Side Intake HR-12, at the top
of the road on the south side, contains lots of gravel and rock from the construction area.
March 5, 2020: Slight increase of sediment was measured in the HDS unit and on the StormFilter vault floor. The filter inserts in the grate inlets along
Haul Road contained only a very small amount of sediment - evidence that they are being serviced periodically.
June 23, 2020: Sediment appears to have migrated south down the west DuroMaxx pipe towards the StormFilter vault. Filter media is mostly discolored
by sediment now but remains porous. The floor of the vault contains no more than 2" of sediment at the deepest. Over 4" of sediment on the floor is the
threshold at which maintenance is needed. A dusting of sediment is now visible on the isolator, but not deep enough to be measured. All filter inserts in
the grate inlets along Haul Road show signs of being emptied periodically.
September 16, 2020: Major rain events in July and August appear to have filled in the StormFilter Vault. While there is still some porosity left in the filter
media itself, the sediment on the tops of the cartridges and the floor of the vault have met the criteria for when maintenance is due. Maintenance is
recommended to remove up to 5" of sediment from the west DuroMaxx pipe (the east is mostly clean) and to remove sediment and replace filter media
cartridges in the StormFilter vault.
December 8, 2020: The HDS unit continues to add only 0.5 inches of sediment on a quarterly basis. Flexstorm filter inserts in grate inlets along Haul
Road continue to be maintained.
March 19, 2021: Purchase orders have been generated to provide the needed maintenance on the StormFilter Vault and the West DuroMaxx pipe. All
maintenance will be scheduled when weather is appropriate for the commercial vacuum truck to access the site without issue. Previous experience has
shown that the ground needs to be adequately dried out or else the truck can get stuck, which might not be until the summer. All FlexStorm inlet inserts
are receiving frequent maintenance to remove sediment that has been captured.
June 8, 2021: Maintenance is tentatively planned for June 17 & 18th. We spoke with Munie about trimming vegetation back from all manholes and
structural components of the system so that maintenance and inspections can occur without interference. As infiltration through the StormFilter system
slows, sediment continues to collect in the DuroMaxx system. In previous visits, no sediment was visible at the south end of the east pipe. Now about 0.5"
of sediment is visible at the south end, increasing up to about 2" on the sides at the north end.
September 8, 2021: Maintenance on the west DuroMaxx pipe and StormFilter was completed in June 2021. Some sediment is already collecting in these
structures, including up to 0.25" on the sides of the pipe and up to 1.5" on the StormFilter vault floor and about four of the cartridge tops.
December 7, 2021: All parts of the system appear to remain in good condition.
March 2, 2022: Sediment continues to increase in all parts of the system but no maintenance is needed.
June 22, 2022: A decrease of sediment was measured in the HDS unit. No significant changes were noted in any of the other components.
September 22, 2022: An increase of 1.5 inches of sediment was measured in the HDS unit. Sediment has continued to increase in the StormFilter vault,
now showing up to 3 inches at the west perimeter around the outlet module and around 2 cartridges.
December 7, 2022: Sediment continues to increase in the StormFilter vault, HDS unit and StormTech isolator row.
March 7, 2023: HDS unit added 3 inches of sediment and is now just over 70% of capacity. At this rate, it will likely need to be cleaned in quarter 4 2023
or quarter 1 2024. One Flexstorm filter insert looks to be torn right at the side intake expansion of the filter insert. The filter should be replaced.
June 7, 2023: Sediment in the HDS unit decreased by 1.5 inches.
September 20, 2023: The cap was removed from the inspection port during the last inspection so it could dewater. Sediment below the inspection port
was measured at 0.75 inches.
December 6, 2023: Leaves and sediment continue to collect in Flexstorm filter inserts - maintenance should be completed before the next quarterly
inspection. Sediment in the HDS unit seemed to decrease slightly, but continues to slowly increase in the StormFilter unit.
BAYER –
Haul Road Stormwater BMP Photos
December 6, 2023
1. HDS UNIT IS AT 56.25% OF
CAPACITY (GIS-BMP-6380)
2. VIEW OF EAST DUROMAXX
PIPE (GIS-BMP-6384)
3. VIEW OF WEST DUROMAXX
PIPE (GIS-BMP-6384)
4. VIEW INTO STORMFILTER
VAULT (GIS-BMP-6385)
5. MINIMAL SEDIMENT AT
MIDDLE OF STORMFILTER VAULT
6. UP TO 3” OF SEDIMENT AT
WEST PART OF VAULT
7. FILTER MEDIA REMAINS IN
GOOD CONDITION
8. FILTER MEDIA REMAINS IN
DECENT CONDITION
9. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
10. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
11. VIEW OF CS HR 19 SHOWING
CONTROL STRUCTURE IS CLEAR
12. REPLACE FLEXSTORM FILTER
INSERT IN GRATE INLET HR-7
Post-Construction Stormwater BMP Inspection and Maintenance Record
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West
Chesterfield, MO 63017
Customer:Bayer
Contact:Anna Tang
Phone Number:314-694-3169
Email:anna.tang@bayer.com Inspector(s):Marianne Pott
Company:Stormwater STL LLC
Address:6514 Lansdowne Avenue 63109
Record Start Date:March 28, 2011 Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
BIOR BIORETENTION/RAINGARDEN (A)P-1 MICROPOOL EXTENDED DETENTION POND (A)
BIOS BIORETENTION/RAINGARDEN (SMALL) (A)P-2 WET POND (A)
GRWD GRAVEL WETLAND (A)P-3 WET EXTENDED DETENTION POND (A)
CIST CISTERN/DRYWELL (U)P-5 POCKET POND (A)
O-1 DRY SWALE - LARGE (A)W-2 ED SHALLOW WETLAND (A)
O-2 DRY SWALE - SMALL (A)W-3 POND/WETLAND SYSTEM (A)
O-3 WET SWALE - LARGE (A)SCDN STORM CREDIT - DISCONNECT NONROOFTOP (A)
O-4 WET SWALE - SMALL (A)SCDR STORM CREDIT - DISCONNECT ROOFTOP (A)
1 HDSP PROPRIETARY HYDRODYNAMIC SEPARATOR SCES STORM CREDIT - ENVIRONMENTALLY SENSTV(A)
I-1 INFILTRATION TRENCH (A)SCNA STORM CREDIT - NATURAL AREA CONSERVA (A)
I-2 INFILTRATION BASIN (A)SCOC STORM CREDIT - OPEN CHANNEL USE (A)
AMDS AMENDED SOILS (A)SCSB STORM CREDIT - SHEET FLOW TO BUFFER (A)
GRRF GREEN ROOF (A)F-1 SURFACE SAND FILTER (A)
O-5 FILTER STRIPS - LARGE (A)F-3 PERIMETER SAND FILTER (A)
O-6 FILTER STRIPS - SMALL (A)F-4 ORGANIC FILTER (A)
PPAS PERMEABLE PAVEMENT - ASPHALT (A)F-5 POCKET SAND FILTER (A)
PPBK PERMEABLE PAVEMENT - PAVER BLOCK (A)1 F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
DET DETENTION 1 WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2011.03.28 Inspection 2018.09.10 Inspection
2012.08.21 One-inch rainfall inspection by CBRE 2018.12.11 Inspection
2012.09.04 One-inch rainfall inspection by CBRE 2019.03.11 Inspection
2012.09.10 One-inch rainfall inspection by CBRE 2019.05.14 Maintenance on StormFilter Vault
2012.11.12 One-inch rainfall inspection by CBRE 2019.06.13 Inspection
2013.01.28 One-inch rainfall inspection by CBRE 2019.06.11 Maintenance on Stormtech System
2013.03.13 One-inch rainfall inspection by CBRE 2019.07.02 Maintenance on Stormtech System
2013.03.21 Inspection by Stormwater STL 2019.09.17 Inspection
2013.03.31 2012 Annual Report submission to MSD 2019.12.11 Inspection
2014.03.28 Inspection 2020.03.05 Inspection
2014.03.29 2013 Annual Report submission to MSD 2020.06.23 Inspection
2014.12.08 Inspection 2020.09.16 Inspection
2015.03.11 Inspection 2020.12.08 Inspection
2015.03.23 2014 Annual Report submission to MSD 2021.03.19 Inspection
2015.05.14 Replaced top and vacuumed HDS 2021.06.08 Inspection
2015.06.11 Restored site using GrowSoxx to build a retaining wall 2021.06.17 Maintenance Filters & Duramax Pipe
2015.06.11 Inspection 2021.09.08 Inspection
2015.06.11 Completed restoration of area around HDS 2021.12.07 Inspection
2015.09.10 Inspection 2022.03.02 Inspection
2015.10.12 Maintenance - Cleaned Inlets & Installed FlexStorm Inserts 2022.06.22 Inspection
2015.10.13 2022.09.22 Inspection
2015.10.14 2022.12.07 Inspection
2015.10.15 Maintenance on StormFilter Vault 2023.03.07 Inspection
2015.12.09 Inspection 2023.06.07 Inspection
2016.02.23 Inspection 2023.09.20 Inspection
2016.06.20 Inspection 2023.12.06 Inspection
2016.09.14 Inspection
2016.09.21 Maintenance on HDS Unit & StormFilter Vault
2016.12.06 Inspection
2017.02.22 Maintenance on DuroMaxx WQ Storage
2017.03.02 Inspection
2017.06.19 Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
(See Next Column)
Maintenance on HDS Unit & DuroMaxx WQ Storage
Maintenance on DuroMaxx WQ Storage
4
Bayer Equip #:
Post-Construction Stormwater BMP Inspection Report
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West 63017
Inspection Date:December 6, 2023
Time:9:30 AM
Weather:39°F; Sunny
Last rain event:0.01" on December 5, 2023
Last one inch rainfall:1.62" on September 27, 2023
Bayer Inspector(s):Marianne Pott
Anna Tang Company:Stormwater STL LLC
314-694-3169 Address:6514 Lansdowne Avenue 63109
anna.tang@bayer.com Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Last Inspection Date:September 20, 2023
Inspector's Summary:
Status of Open Action Items Identified During This Reporting Year:
Grate Inlet with Side Intake HR-7
Access Points to Haul Road Inspection
Action Items Identified During This Inspection:
No new action items were identified during this inspection.
Page 1
This document has been prepared exclusively for the Customer noted above (Customer) by Stormwater STL LLC (Stormwater STL), based on a visual inspection conducted on the date(s) noted
above. Unless specifically indicated, Stormwater STL did not undertake any forensic investigation at this location on the date(s) noted. The opinions expressed in this document relate only to the
condition of the site and the Post-Construction Stormwater BMP(s) as observed by Stormwater STL on the date(s) noted. The content of this document reflects the opinion of Stormwater STL only
and Stormwater STL makes no express or implied representation or warranty with respect to the conditions described or the functionality of the systems identified in this report. Other than Customer,
third parties who rely upon this document do so solely at their own risk and Stormwater STL disclaims all liability, damages or loss with respect to such reliance. Neither Customer nor Stormwater
STL, nor any person acting for and/or on behalf of those companies, assumes any responsibility, duty of care or liability to any person to update the contents of this document or to distribute any
subsequently learned information to recipients of this document other than to Customer. This disclaimer must accompany every copy of this document, which is an integral document and must be
read in its entirety.
Construction for this project was approved by MSD on October 14, 2010. Stormwater BMPs associated with this system include a Contech
Hydrodynamic Separator, a 72" DuroMaxx Water Quality Storage, a Contech StormFilter Vault, StormTech Chambers, and associated
private inlets, manholes, and piping. Grate Inlets along Haul Road accumulate excessive sediment and were therefore modified in October
2015 with the installation of 16 flex storm grate inlet filter inserts. Despite these modifications, maintenance to remove sediment from the
system has been required every few years, most recently June 2021 with servicing the StormFilter Vault and the west DuroMaxx pipe. After
carefully reviewing each component of the system and finding only one small maintenance item to be addressed, I am pleased to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent.
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer) --- COMPLETED / ONGOINGGrate Inlets with Side Intakes along Haul Road
Phone Number:
Email:
CLEAR brush around all manholes prior to inspections (Bayer) --- COMPLETED / ONGOING
REPLACE Flexstorm filter insert in Grate Inlet HR-7 (Bayer) --- NOT COMPLETED
Bayer Equip #:
Customer:
Contact:
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Comments
Access
Clogging
Water ponding on surface
Sheen on water surface
Odor
Sediment
Mulch na
Turf na
Weeds na
Underdrain na
Structural components
14'-6.5"
15'-8"
1'-1.5"
2'-0"
72" DuroMaxx Water Quality Storage (GIS-BMP-6384)
Comments
Access
Trash/debris
Sediment buildup in east/uphill pipe
Sediment buildup in west/downhill pipe
Water ponding on bottom
Structural components
Comments
Access
Water ponding on surface
Sheen on water surface na
Odor
Erosion na
Mulch na
Turf na
Plants na
Weeds na
Underdrain
Structural components
1/8" avg
Underground StormTech Detention with MC-3500 Chambers (GIS-BMP-5805)
Comments
Access
Trash/debris
Estimated sediment buildup from MH HR-1
Measured sediment buildup from inspection port
Water ponding on bottom
Structural components Maintenance was conducted in July 2019
Private Inlets/Manholes/Piping
Comments
Miscellaneous
Comments
Page 2Bayer Haul Road System - December 6, 2023
Mosquitoes
Encroachment(s) on facility or easement
Pretreatment - Contech VortSentry HS72 Hydrodynamic Separator in MH HS 2B (GIS-BMP-6380)
REPLACE Flexstorm filter insert in Grate Inlet HR-7, photo 12 (Bayer)
Condition of filter media
Max. sediment depth recommended by manufacturer =
Access
Sediment
Sediment coating 4 cartridge tops along west perimeter; could be up to 0.25"
No indications of clogging
Filter fabric visible in front 33% of row; sediment collecting in back 67%, photo 9 & 10
Sediment visible in channels of MH HR-1
No sheen visible on water surface
Vegetation around manholes was cut down and removed
Decrease of 0.5" since September 2023 inspection
Trash/debris
Other (describe) (Haul Road Surface)
None
Depth of sediment =
HDS unit is at 56.25% of capacity, photo 1
Contech StormFilter Stormwater Quality System in MH 2G with 12 Cartridges (GIS-BMP-6385)
Trash/debris
No vertical access to underdrain manifold; float valves appear functional
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer)
No erosion or settlement noted
Clear, photo 11
Erosion/settlement around structures
Estimated 1.5" of sediment and rock visible below north manhole, photo 2
Complaints None of which I'm aware
Top 4" of filter media remains porous, below 4" is filling in with sediment, photos 7 & 8
No ponding water in isolator row
Depth of silt on filter cartridge tops
Clogging
Depth of sediment on vault floor
Sediment was removed and 12 filter cartridges were replaced in June 2021
No ponding water
System discharge
Trash/debris - Grated Curb Inlets
Erosion
Up to 3" of sediment and leaves near outflow module & below ladder, photo 6
No odor
Some leaves collecting in StormFilter vault
0.125 - 0.5" of sediment on walls; 0.75 - 1" on bottom with 2 - 2.5" in low spots, photo 3
Sediment measured as 0.75" below inspection port
HDS unit was last maintained on 9/21/2016
Distance from rim to sediment =
Distance from rim to bottom =
None
Post-Construction Stormwater BMP Inspection Report
Photographs
See attached sheet
Inspector's Notes
Page 3Bayer Haul Road System - December 6, 2023
March 11, 2019: Maintenance for open action items has been approved and will be scheduled once the weather cooperates. Due to the weight of the
commercial vacuum truck, the ground surrounding the system needs to be dry and stable --- conditions that have been hard to come by with this wet
winter.
June 13, 2019: Maintenance was completed on the StormFilter vault but the weather, etc. has not yet allowed for maintenance of the isolator row. No
increase of sediment was measured in the HDS unit. Filter media in the StormFilter vault remains in original condition with no visible signs of sediment
accumulation. A very minor amount of sediment was noted on the vault floor and tops of the cartridges.
September 17, 2019: All maintenance items were completed and each BMP remains in good condition. Locust saplings from brush control efforts along
the road above the system were cut and dumped down the hill, where we found heavy brush covering manholes. For future summer inspections, it would
be helpful to maintain a few feet of brush clearance around the manholes access for the inspection.
December 11, 2019: A slight increase of sediment was measured in the HDS unit. Sediment in the other treatment and storage components remains
stable. The filter inserts in the grate inlets along Haul Road should continue to be emptied on a periodic basis. They each contained a few inches of
sediment, leaves and debris. This is more than in previous visits but far from being at capacity. The one in Grate Inlet with Side Intake HR-12, at the top
of the road on the south side, contains lots of gravel and rock from the construction area.
March 5, 2020: Slight increase of sediment was measured in the HDS unit and on the StormFilter vault floor. The filter inserts in the grate inlets along
Haul Road contained only a very small amount of sediment - evidence that they are being serviced periodically.
June 23, 2020: Sediment appears to have migrated south down the west DuroMaxx pipe towards the StormFilter vault. Filter media is mostly discolored
by sediment now but remains porous. The floor of the vault contains no more than 2" of sediment at the deepest. Over 4" of sediment on the floor is the
threshold at which maintenance is needed. A dusting of sediment is now visible on the isolator, but not deep enough to be measured. All filter inserts in
the grate inlets along Haul Road show signs of being emptied periodically.
September 16, 2020: Major rain events in July and August appear to have filled in the StormFilter Vault. While there is still some porosity left in the filter
media itself, the sediment on the tops of the cartridges and the floor of the vault have met the criteria for when maintenance is due. Maintenance is
recommended to remove up to 5" of sediment from the west DuroMaxx pipe (the east is mostly clean) and to remove sediment and replace filter media
cartridges in the StormFilter vault.
December 8, 2020: The HDS unit continues to add only 0.5 inches of sediment on a quarterly basis. Flexstorm filter inserts in grate inlets along Haul
Road continue to be maintained.
March 19, 2021: Purchase orders have been generated to provide the needed maintenance on the StormFilter Vault and the West DuroMaxx pipe. All
maintenance will be scheduled when weather is appropriate for the commercial vacuum truck to access the site without issue. Previous experience has
shown that the ground needs to be adequately dried out or else the truck can get stuck, which might not be until the summer. All FlexStorm inlet inserts
are receiving frequent maintenance to remove sediment that has been captured.
June 8, 2021: Maintenance is tentatively planned for June 17 & 18th. We spoke with Munie about trimming vegetation back from all manholes and
structural components of the system so that maintenance and inspections can occur without interference. As infiltration through the StormFilter system
slows, sediment continues to collect in the DuroMaxx system. In previous visits, no sediment was visible at the south end of the east pipe. Now about 0.5"
of sediment is visible at the south end, increasing up to about 2" on the sides at the north end.
September 8, 2021: Maintenance on the west DuroMaxx pipe and StormFilter was completed in June 2021. Some sediment is already collecting in these
structures, including up to 0.25" on the sides of the pipe and up to 1.5" on the StormFilter vault floor and about four of the cartridge tops.
December 7, 2021: All parts of the system appear to remain in good condition.
March 2, 2022: Sediment continues to increase in all parts of the system but no maintenance is needed.
June 22, 2022: A decrease of sediment was measured in the HDS unit. No significant changes were noted in any of the other components.
September 22, 2022: An increase of 1.5 inches of sediment was measured in the HDS unit. Sediment has continued to increase in the StormFilter vault,
now showing up to 3 inches at the west perimeter around the outlet module and around 2 cartridges.
December 7, 2022: Sediment continues to increase in the StormFilter vault, HDS unit and StormTech isolator row.
March 7, 2023: HDS unit added 3 inches of sediment and is now just over 70% of capacity. At this rate, it will likely need to be cleaned in quarter 4 2023
or quarter 1 2024. One Flexstorm filter insert looks to be torn right at the side intake expansion of the filter insert. The filter should be replaced.
June 7, 2023: Sediment in the HDS unit decreased by 1.5 inches.
September 20, 2023: The cap was removed from the inspection port during the last inspection so it could dewater. Sediment below the inspection port
was measured at 0.75 inches.
December 6, 2023: Leaves and sediment continue to collect in Flexstorm filter inserts - maintenance should be completed before the next quarterly
inspection. Sediment in the HDS unit seemed to decrease slightly, but continues to slowly increase in the StormFilter unit.
BAYER –
Haul Road Stormwater BMP Photos
December 6, 2023
1. HDS UNIT IS AT 56.25% OF
CAPACITY (GIS-BMP-6380)
2. VIEW OF EAST DUROMAXX
PIPE (GIS-BMP-6384)
3. VIEW OF WEST DUROMAXX
PIPE (GIS-BMP-6384)
4. VIEW INTO STORMFILTER
VAULT (GIS-BMP-6385)
5. MINIMAL SEDIMENT AT
MIDDLE OF STORMFILTER VAULT
6. UP TO 3” OF SEDIMENT AT
WEST PART OF VAULT
7. FILTER MEDIA REMAINS IN
GOOD CONDITION
8. FILTER MEDIA REMAINS IN
DECENT CONDITION
9. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
10. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
11. VIEW OF CS HR 19 SHOWING
CONTROL STRUCTURE IS CLEAR
12. REPLACE FLEXSTORM FILTER
INSERT IN GRATE INLET HR-7
Post-Construction Stormwater BMP Inspection and Maintenance Record
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West
Chesterfield, MO 63017
Customer:Bayer
Contact:Anna Tang
Phone Number:314-694-3169
Email:anna.tang@bayer.com Inspector(s):Marianne Pott
Company:Stormwater STL LLC
Address:6514 Lansdowne Avenue 63109
Record Start Date:March 28, 2011 Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
BIOR BIORETENTION/RAINGARDEN (A)P-1 MICROPOOL EXTENDED DETENTION POND (A)
BIOS BIORETENTION/RAINGARDEN (SMALL) (A)P-2 WET POND (A)
GRWD GRAVEL WETLAND (A)P-3 WET EXTENDED DETENTION POND (A)
CIST CISTERN/DRYWELL (U)P-5 POCKET POND (A)
O-1 DRY SWALE - LARGE (A)W-2 ED SHALLOW WETLAND (A)
O-2 DRY SWALE - SMALL (A)W-3 POND/WETLAND SYSTEM (A)
O-3 WET SWALE - LARGE (A)SCDN STORM CREDIT - DISCONNECT NONROOFTOP (A)
O-4 WET SWALE - SMALL (A)SCDR STORM CREDIT - DISCONNECT ROOFTOP (A)
1 HDSP PROPRIETARY HYDRODYNAMIC SEPARATOR SCES STORM CREDIT - ENVIRONMENTALLY SENSTV(A)
I-1 INFILTRATION TRENCH (A)SCNA STORM CREDIT - NATURAL AREA CONSERVA (A)
I-2 INFILTRATION BASIN (A)SCOC STORM CREDIT - OPEN CHANNEL USE (A)
AMDS AMENDED SOILS (A)SCSB STORM CREDIT - SHEET FLOW TO BUFFER (A)
GRRF GREEN ROOF (A)F-1 SURFACE SAND FILTER (A)
O-5 FILTER STRIPS - LARGE (A)F-3 PERIMETER SAND FILTER (A)
O-6 FILTER STRIPS - SMALL (A)F-4 ORGANIC FILTER (A)
PPAS PERMEABLE PAVEMENT - ASPHALT (A)F-5 POCKET SAND FILTER (A)
PPBK PERMEABLE PAVEMENT - PAVER BLOCK (A)1 F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
DET DETENTION 1 WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2011.03.28 Inspection 2018.09.10 Inspection
2012.08.21 One-inch rainfall inspection by CBRE 2018.12.11 Inspection
2012.09.04 One-inch rainfall inspection by CBRE 2019.03.11 Inspection
2012.09.10 One-inch rainfall inspection by CBRE 2019.05.14 Maintenance on StormFilter Vault
2012.11.12 One-inch rainfall inspection by CBRE 2019.06.13 Inspection
2013.01.28 One-inch rainfall inspection by CBRE 2019.06.11 Maintenance on Stormtech System
2013.03.13 One-inch rainfall inspection by CBRE 2019.07.02 Maintenance on Stormtech System
2013.03.21 Inspection by Stormwater STL 2019.09.17 Inspection
2013.03.31 2012 Annual Report submission to MSD 2019.12.11 Inspection
2014.03.28 Inspection 2020.03.05 Inspection
2014.03.29 2013 Annual Report submission to MSD 2020.06.23 Inspection
2014.12.08 Inspection 2020.09.16 Inspection
2015.03.11 Inspection 2020.12.08 Inspection
2015.03.23 2014 Annual Report submission to MSD 2021.03.19 Inspection
2015.05.14 Replaced top and vacuumed HDS 2021.06.08 Inspection
2015.06.11 Restored site using GrowSoxx to build a retaining wall 2021.06.17 Maintenance Filters & Duramax Pipe
2015.06.11 Inspection 2021.09.08 Inspection
2015.06.11 Completed restoration of area around HDS 2021.12.07 Inspection
2015.09.10 Inspection 2022.03.02 Inspection
2015.10.12 Maintenance - Cleaned Inlets & Installed FlexStorm Inserts 2022.06.22 Inspection
2015.10.13 2022.09.22 Inspection
2015.10.14 2022.12.07 Inspection
2015.10.15 Maintenance on StormFilter Vault 2023.03.07 Inspection
2015.12.09 Inspection 2023.06.07 Inspection
2016.02.23 Inspection 2023.09.20 Inspection
2016.06.20 Inspection 2023.12.06 Inspection
2016.09.14 Inspection
2016.09.21 Maintenance on HDS Unit & StormFilter Vault
2016.12.06 Inspection
2017.02.22 Maintenance on DuroMaxx WQ Storage
2017.03.02 Inspection
2017.06.19 Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
(See Next Column)
Maintenance on HDS Unit & DuroMaxx WQ Storage
Maintenance on DuroMaxx WQ Storage
4
Bayer Equip #:
Post-Construction Stormwater BMP Inspection Report
261386
MSD P Number:P001174320
Project:Bayer Haul Road
Address:700 Chesterfield Parkway West 63017
Inspection Date:December 6, 2023
Time:9:30 AM
Weather:39°F; Sunny
Last rain event:0.01" on December 5, 2023
Last one inch rainfall:1.62" on September 27, 2023
Bayer Inspector(s):Marianne Pott
Anna Tang Company:Stormwater STL LLC
314-694-3169 Address:6514 Lansdowne Avenue 63109
anna.tang@bayer.com Phone:(314) 229-8334
E-mail:marianne@stormwater-stl.net
Last Inspection Date:September 20, 2023
Inspector's Summary:
Status of Open Action Items Identified During This Reporting Year:
Grate Inlet with Side Intake HR-7
Access Points to Haul Road Inspection
Action Items Identified During This Inspection:
No new action items were identified during this inspection.
Page 1
This document has been prepared exclusively for the Customer noted above (Customer) by Stormwater STL LLC (Stormwater STL), based on a visual inspection conducted on the date(s) noted
above. Unless specifically indicated, Stormwater STL did not undertake any forensic investigation at this location on the date(s) noted. The opinions expressed in this document relate only to the
condition of the site and the Post-Construction Stormwater BMP(s) as observed by Stormwater STL on the date(s) noted. The content of this document reflects the opinion of Stormwater STL only
and Stormwater STL makes no express or implied representation or warranty with respect to the conditions described or the functionality of the systems identified in this report. Other than Customer,
third parties who rely upon this document do so solely at their own risk and Stormwater STL disclaims all liability, damages or loss with respect to such reliance. Neither Customer nor Stormwater
STL, nor any person acting for and/or on behalf of those companies, assumes any responsibility, duty of care or liability to any person to update the contents of this document or to distribute any
subsequently learned information to recipients of this document other than to Customer. This disclaimer must accompany every copy of this document, which is an integral document and must be
read in its entirety.
Construction for this project was approved by MSD on October 14, 2010. Stormwater BMPs associated with this system include a Contech
Hydrodynamic Separator, a 72" DuroMaxx Water Quality Storage, a Contech StormFilter Vault, StormTech Chambers, and associated
private inlets, manholes, and piping. Grate Inlets along Haul Road accumulate excessive sediment and were therefore modified in October
2015 with the installation of 16 flex storm grate inlet filter inserts. Despite these modifications, maintenance to remove sediment from the
system has been required every few years, most recently June 2021 with servicing the StormFilter Vault and the west DuroMaxx pipe. After
carefully reviewing each component of the system and finding only one small maintenance item to be addressed, I am pleased to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent.
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer) --- COMPLETED / ONGOINGGrate Inlets with Side Intakes along Haul Road
Phone Number:
Email:
CLEAR brush around all manholes prior to inspections (Bayer) --- COMPLETED / ONGOING
REPLACE Flexstorm filter insert in Grate Inlet HR-7 (Bayer) --- NOT COMPLETED
Bayer Equip #:
Customer:
Contact:
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Comments
Access
Clogging
Water ponding on surface
Sheen on water surface
Odor
Sediment
Mulch na
Turf na
Weeds na
Underdrain na
Structural components
14'-6.5"
15'-8"
1'-1.5"
2'-0"
72" DuroMaxx Water Quality Storage (GIS-BMP-6384)
Comments
Access
Trash/debris
Sediment buildup in east/uphill pipe
Sediment buildup in west/downhill pipe
Water ponding on bottom
Structural components
Comments
Access
Water ponding on surface
Sheen on water surface na
Odor
Erosion na
Mulch na
Turf na
Plants na
Weeds na
Underdrain
Structural components
1/8" avg
Underground StormTech Detention with MC-3500 Chambers (GIS-BMP-5805)
Comments
Access
Trash/debris
Estimated sediment buildup from MH HR-1
Measured sediment buildup from inspection port
Water ponding on bottom
Structural components Maintenance was conducted in July 2019
Private Inlets/Manholes/Piping
Comments
Miscellaneous
Comments
Page 2Bayer Haul Road System - December 6, 2023
Mosquitoes
Encroachment(s) on facility or easement
Pretreatment - Contech VortSentry HS72 Hydrodynamic Separator in MH HS 2B (GIS-BMP-6380)
REPLACE Flexstorm filter insert in Grate Inlet HR-7, photo 12 (Bayer)
Condition of filter media
Max. sediment depth recommended by manufacturer =
Access
Sediment
Sediment coating 4 cartridge tops along west perimeter; could be up to 0.25"
No indications of clogging
Filter fabric visible in front 33% of row; sediment collecting in back 67%, photo 9 & 10
Sediment visible in channels of MH HR-1
No sheen visible on water surface
Vegetation around manholes was cut down and removed
Decrease of 0.5" since September 2023 inspection
Trash/debris
Other (describe) (Haul Road Surface)
None
Depth of sediment =
HDS unit is at 56.25% of capacity, photo 1
Contech StormFilter Stormwater Quality System in MH 2G with 12 Cartridges (GIS-BMP-6385)
Trash/debris
No vertical access to underdrain manifold; float valves appear functional
REMOVE sediment & debris from all FlexStorm inlet filters (Bayer)
No erosion or settlement noted
Clear, photo 11
Erosion/settlement around structures
Estimated 1.5" of sediment and rock visible below north manhole, photo 2
Complaints None of which I'm aware
Top 4" of filter media remains porous, below 4" is filling in with sediment, photos 7 & 8
No ponding water in isolator row
Depth of silt on filter cartridge tops
Clogging
Depth of sediment on vault floor
Sediment was removed and 12 filter cartridges were replaced in June 2021
No ponding water
System discharge
Trash/debris - Grated Curb Inlets
Erosion
Up to 3" of sediment and leaves near outflow module & below ladder, photo 6
No odor
Some leaves collecting in StormFilter vault
0.125 - 0.5" of sediment on walls; 0.75 - 1" on bottom with 2 - 2.5" in low spots, photo 3
Sediment measured as 0.75" below inspection port
HDS unit was last maintained on 9/21/2016
Distance from rim to sediment =
Distance from rim to bottom =
None
Post-Construction Stormwater BMP Inspection Report
Photographs
See attached sheet
Inspector's Notes
Page 3Bayer Haul Road System - December 6, 2023
March 11, 2019: Maintenance for open action items has been approved and will be scheduled once the weather cooperates. Due to the weight of the
commercial vacuum truck, the ground surrounding the system needs to be dry and stable --- conditions that have been hard to come by with this wet
winter.
June 13, 2019: Maintenance was completed on the StormFilter vault but the weather, etc. has not yet allowed for maintenance of the isolator row. No
increase of sediment was measured in the HDS unit. Filter media in the StormFilter vault remains in original condition with no visible signs of sediment
accumulation. A very minor amount of sediment was noted on the vault floor and tops of the cartridges.
September 17, 2019: All maintenance items were completed and each BMP remains in good condition. Locust saplings from brush control efforts along
the road above the system were cut and dumped down the hill, where we found heavy brush covering manholes. For future summer inspections, it would
be helpful to maintain a few feet of brush clearance around the manholes access for the inspection.
December 11, 2019: A slight increase of sediment was measured in the HDS unit. Sediment in the other treatment and storage components remains
stable. The filter inserts in the grate inlets along Haul Road should continue to be emptied on a periodic basis. They each contained a few inches of
sediment, leaves and debris. This is more than in previous visits but far from being at capacity. The one in Grate Inlet with Side Intake HR-12, at the top
of the road on the south side, contains lots of gravel and rock from the construction area.
March 5, 2020: Slight increase of sediment was measured in the HDS unit and on the StormFilter vault floor. The filter inserts in the grate inlets along
Haul Road contained only a very small amount of sediment - evidence that they are being serviced periodically.
June 23, 2020: Sediment appears to have migrated south down the west DuroMaxx pipe towards the StormFilter vault. Filter media is mostly discolored
by sediment now but remains porous. The floor of the vault contains no more than 2" of sediment at the deepest. Over 4" of sediment on the floor is the
threshold at which maintenance is needed. A dusting of sediment is now visible on the isolator, but not deep enough to be measured. All filter inserts in
the grate inlets along Haul Road show signs of being emptied periodically.
September 16, 2020: Major rain events in July and August appear to have filled in the StormFilter Vault. While there is still some porosity left in the filter
media itself, the sediment on the tops of the cartridges and the floor of the vault have met the criteria for when maintenance is due. Maintenance is
recommended to remove up to 5" of sediment from the west DuroMaxx pipe (the east is mostly clean) and to remove sediment and replace filter media
cartridges in the StormFilter vault.
December 8, 2020: The HDS unit continues to add only 0.5 inches of sediment on a quarterly basis. Flexstorm filter inserts in grate inlets along Haul
Road continue to be maintained.
March 19, 2021: Purchase orders have been generated to provide the needed maintenance on the StormFilter Vault and the West DuroMaxx pipe. All
maintenance will be scheduled when weather is appropriate for the commercial vacuum truck to access the site without issue. Previous experience has
shown that the ground needs to be adequately dried out or else the truck can get stuck, which might not be until the summer. All FlexStorm inlet inserts
are receiving frequent maintenance to remove sediment that has been captured.
June 8, 2021: Maintenance is tentatively planned for June 17 & 18th. We spoke with Munie about trimming vegetation back from all manholes and
structural components of the system so that maintenance and inspections can occur without interference. As infiltration through the StormFilter system
slows, sediment continues to collect in the DuroMaxx system. In previous visits, no sediment was visible at the south end of the east pipe. Now about 0.5"
of sediment is visible at the south end, increasing up to about 2" on the sides at the north end.
September 8, 2021: Maintenance on the west DuroMaxx pipe and StormFilter was completed in June 2021. Some sediment is already collecting in these
structures, including up to 0.25" on the sides of the pipe and up to 1.5" on the StormFilter vault floor and about four of the cartridge tops.
December 7, 2021: All parts of the system appear to remain in good condition.
March 2, 2022: Sediment continues to increase in all parts of the system but no maintenance is needed.
June 22, 2022: A decrease of sediment was measured in the HDS unit. No significant changes were noted in any of the other components.
September 22, 2022: An increase of 1.5 inches of sediment was measured in the HDS unit. Sediment has continued to increase in the StormFilter vault,
now showing up to 3 inches at the west perimeter around the outlet module and around 2 cartridges.
December 7, 2022: Sediment continues to increase in the StormFilter vault, HDS unit and StormTech isolator row.
March 7, 2023: HDS unit added 3 inches of sediment and is now just over 70% of capacity. At this rate, it will likely need to be cleaned in quarter 4 2023
or quarter 1 2024. One Flexstorm filter insert looks to be torn right at the side intake expansion of the filter insert. The filter should be replaced.
June 7, 2023: Sediment in the HDS unit decreased by 1.5 inches.
September 20, 2023: The cap was removed from the inspection port during the last inspection so it could dewater. Sediment below the inspection port
was measured at 0.75 inches.
December 6, 2023: Leaves and sediment continue to collect in Flexstorm filter inserts - maintenance should be completed before the next quarterly
inspection. Sediment in the HDS unit seemed to decrease slightly, but continues to slowly increase in the StormFilter unit.
BAYER –
Haul Road Stormwater BMP Photos
December 6, 2023
1. HDS UNIT IS AT 56.25% OF
CAPACITY (GIS-BMP-6380)
2. VIEW OF EAST DUROMAXX
PIPE (GIS-BMP-6384)
3. VIEW OF WEST DUROMAXX
PIPE (GIS-BMP-6384)
4. VIEW INTO STORMFILTER
VAULT (GIS-BMP-6385)
5. MINIMAL SEDIMENT AT
MIDDLE OF STORMFILTER VAULT
6. UP TO 3” OF SEDIMENT AT
WEST PART OF VAULT
7. FILTER MEDIA REMAINS IN
GOOD CONDITION
8. FILTER MEDIA REMAINS IN
DECENT CONDITION
9. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
10. VIEW OF ISOLATOR ROW (GIS-
BMP-5805)
11. VIEW OF CS HR 19 SHOWING
CONTROL STRUCTURE IS CLEAR
12. REPLACE FLEXSTORM FILTER
INSERT IN GRATE INLET HR-7