HomeMy Public PortalAboutP001174327_3/8/2024 3:38:51 PMPost-Construction Stormwater BMP Inspection and Maintenance Record
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
Address:700 Chesterfield Parkway West 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
Constr. Approval:May 19, 2017 Phone:(314) 229-8334
Record Start Date:June 19, 2017 E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
2 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)
2 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)F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
1 DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2017.06.19 Initial Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
2018.09.10 Inspection
2018.12.11 Inspection
2019.03.11 Inspection
2019.06.13 Inspection
2019.09.17 Inspection
2019.12.11 Inspection
2020.01.22 Maintenance HDS Unit
2020.03.05 Inspection
2020.06.23 Inspection
2020.09.16 Inspection
2020.12.08 Inspection
2021.03.16 Inspection
2021.06.08 Inspection
2021.09.08 Inspection
2021.12.07 Inspection
2022.03.02 Inspection
2022.06.22 Inspection
2022.09.22 Inspection
2022.11.09 Maintenance HDS Unit ST H15
2022.12.07 Inspection
2023.03.07 Inspection
2023.06.07 Inspection
2023.09.20 Inspection
2023.09.21 Maintenance HDS Unit ST B13
2023.12.06 Inspection
6
Post-Construction Stormwater BMP Inspection Report
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
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:
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D (GIS-BMP-8285)
Biodetention Basin 03A (GIS-BMP-8293)
Surface Detention System (GIS-BMP-8278)
Surface Detention System (GIS-BMP-8278)
Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Action Items Identified During This Inspection:
Biodetention Basin 03A (GIS-BMP-8293)
Page 1
Customer:
Contact:
Phone Number:
Email:
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 the Greenhouse Modernization and Expansion was approved by MSD on May 19, 2017 and includes two hydrodynamic separators that
serve as pretreatment for two biodetention basins, a Stormtech underground stormwater detention basin, and a surface detention basin, as well as
associated private inlets, manholes and piping. The HDS pretreatment was not entirely effective at removing fine particles of silt and clay washing into the
system while the drainage areas of the BMPs were not yet established, and so these materials instead were deposited on the surface of the biodetention
basins. Silt was removed by hand in March 2018 and the drainage areas of these BMPs now appear to have been stabilized with vegetation. The HDS unit
in ST H15 was maintained in January 2020 and September 2023 and in B13 was maintained in November 2022. Therefore, after carefully reviewing each
component of the system and finding only routine maintenance items to be addressed (see below), I can continue to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with its design intent.
CONTROL for growth of invasive weeds (Bayer) --- COMPLETED
CUT AND REMOVE dead plant material before next growing season (Bayer) --- COMPLETED
EXPAND deer exclusion wraps on trees at south end of basin (Bayer) --- NOT COMPLETED
ADD native plants to bare areas of basin (Bayer) --- IN PROGRESS
ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED
VACUUM AND PRESSURE WASH to remove sediment (Bayer) --- COMPLETED
CONTROL for invasive growth in rip rap swale (Bayer) --- COMPLETED
FILL animal burrow at north end of basin, photo 8 (Bayer)
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Diversion Structure in ST B7
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 02D (GIS-BMP-8285)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Diversion Structure in ST H6
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST H15 (GIS-BMP-8301)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 03A (GIS-BMP-8293)
Assessment Comments
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Green
Green
Green
Green
Bayer Greenhouse Modernization - December 6, 2023 Page 2
Max. depth recommended by manufacturer = 2'-0" HDS unit was vacuumed and pressured washed in November 2022, photo 2
Turf No turf; Native plants grasses on embankments were cut down & removed, photo 7
Plants Good coverage of native plants on surface; dead plant growth was removed, photo 7
Weeds Invasive growth was removed during 2023 growing season
Underdrain Underdrain is clear and dry; no discharge observed at ST H13, photo 11
Condition of filter media Filter media is in good condition, photo 9
Mulch Mulch is covering all embankments
Maintenance due when 75% of Max. depth is exceeded Maintenance is needed according to manufacturer's O & M Manual
Attribute
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 7
Clogging No indications of clogging
Water ponding on surface No ponding water
Animal activity FILL animal burrow at north end of basin, photo 8 (Bayer)
Inlet Rock blanket below FES Inlet is above flowline, pushing water to the SE embankment
Erosion MONITOR further scouring of embankment to the southeast of FES inlet, photo 10
Sediment No sediment visible on surface of filter bed, photo 9
Distance from rim to bottom =10'-6" HDS unit was maintained in January 2020 & September 2023
Depth of sediment =0'-1.5" Increase of 1.5" of sediment since September 2023 inspection
Sheen on water surface No sheen
Odor No odor
Structural components Coupling is askew between HDS unit and outlet**
Structural components Clear, photo 3
Trash/debris/sediment Some sediment and gravel in bottom of structure
Distance from rim to sediment =10'-6"
Attribute
Access
Trash/debris/leaves No trash, debris or leaves
Underdrain Underdrain is clear and dry; no discharge observed at ST B5, photo 18
Structural components - ST B5 Clear, photo 18
Condition of filter media Filter media is in good condition, photo 17
Animal activity No further scouring of southeast quadrant of basin
Plants ADD native plants to bare areas of basin, photo 15 (Bayer)
Weeds Invasive growth was removed during 2023 growing season
Attribute
Erosion No erosion noted
Sediment No silt visible on surface of basin
Mulch Mulch is covering south embankment
Water ponding on surface No ponding water
Sheen on water surface N/A
Odor None
Attribute
Access Access is in a mulched landscaping bed
Trash/debris/leaves Some mulch collecting on surface of unit - inevitable due to access
Structural components Clear, photo 1
Trash/debris/sediment
Max. depth recommended by manufacturer = 2'-0" HDS unit is at 6.25% of capacity, photo 4
Distance from rim to sediment =12'-3.5"
Distance from rim to bottom =12'-3.5" No change since November 2022 maintenance
Depth of sediment =0'-0" HDS unit is at 0% of capacity, photo 2
Sheen on water surface No sheen on water surface
Odor No odor
Structural components Coupling is maintaining proper connection between HDS unit and outlet, photo 2
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 13
Clogging No indications of clogging
Maintenance due when 75% of Max. depth is exceeded Maintenance is not needed according to manufacturer's O & M Manual
Post-Construction Stormwater BMP Inspection Report
Assessment Comments
Green
Green
Green
Green
Green
Green
Outfall Structure in ST H4
Assessment Comments
Green
Green
Green
Green
Surface Detention System (GIS-BMP-8278)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Outfall Structure in ST A1
Assessment Comments
Green
Green
Green
Green
Private Inlets/Manholes/Piping
Assessment Comments
Green
Green
Green
Green
Inspector's Notes
Bayer Greenhouse Modernization - December 6, 2023 Page 3
Water ponding on surface No ponding water
Erosion No further erosion below inlet
Native trees EXPAND deer exclusion wraps on trees at south end of basin, photo 21 (Bayer)
None
Sediment buildup on basin bottom
Attribute
Access
Trash/debris/leaves No trash, debris or leaves, photo 19
Sediment buildup at low flow orifice 1.5" of silt noted around concrete foundation of standpipe
Sediment buildup in pipes
Sediment buildup at low flow orifice None, photo 6
Structural components Clear
No sediment visible on basin bottom
Erosion Degradation of concrete seams in parking lot above basin 03A, photo 12
Turf Turf throughout basin is in good condition
Native trees Bald cypress trees are losing their leaves
Weeds Invasive growth in rip rap swale was managed during the growing season, photo 20
Access
Attribute
Access
Trash/debris/leaves EOP is clear of sediment, debris and leaves
Underdrain N/A
Structural components No further shifting of concrete foundation of standpipe was noted, photo 22
Sediment buildup at low flow orifice Minimal
Structural components Clear, photo 24
Trash/debris/leaves
System discharge Clear, photo 24
Attribute
Attribute
Access
Trash/debris/leaves None
Water ponding on bottom No ponding water below access pipe
Structural components Foundation stone adjacent to access pipe is not level, holds some sediment and water
Structural components MONITOR separation in seam of eccentric header pipe
Average sediment buildup 0.125 - 0.5" of sediment appears to cover the entire row, photo 5
Measured sediment buildup 1.125" of sediment measured at inspection port on 6/7/2023, photo 5
Stormtech Underground Stormwater Detention System in ST H5 (GIS-BMP-8292)
Attribute
Access Thigh or chest waders needed, at least 3' water in ST H5
IMPORTANT NOTE ABOUT PLANT MATERIALS IN STORMWATER QUALITY SYSTEMS
Dead plant and other organic materials, if allowed to lay on the surface of your stormwater quality filter(s) for an extended period, will decay and cause
premature clogging. Often, removal and replacement of some or all of the filter media and plant materials are required to restore full functionality. Removal
of dead plant materials and other organics each fall will extend the life of the stormwater quality system and reduce maintenance and repair costs.
If you have questions about plant maintenance or would like to develop a stewardship program to protect your stormwater quality assets, please let me
know.
June 7, 2023: Invasive growth in both biodetention basins, and in the rip rap swale of the surface detention basin, should continue to be managed. Timing
is not appropriate for adding more native plants to biodetention basin 02D, but arrangements should be made for doing this in the fall or spring. The
landscaping mesh around the trees in the surface detention basin need to be expanded - they are cutting into the tree bark. The HDS unit in ST H15 at
biodetention basin 03A has exceeded 75% of its capacity and therefore needs to be cleanout out.
September 20, 2023: Stormwater continues to scour the embankment to the southeast of the inlet in biodetention basin 03A. Some weeds noted during
the previous inspection seem to have been removed, but more weedy growth remains in the biodetention basins. The HDS unit was vacuumed and
pressure washed on 9/21/2023.
December 6, 2023: Dead plant growth was removed from the biodetention basins. Removal of dead plant growth revealed a new animal burrow at the
north end of biodetention basin 03A. An increase of 1.5" of sediment was measured in the HDS unit at ST H15. Gravel in the diversion structure and in
grate inlets in the parking lot above biodetention basin 03A show some gravel, which could perhaps be from the deterioration of the concrete seams in the
parking lot.
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
1. DIVERSION STRUCTURE IN ST B7 IS
CLEAR
2. HDS UNIT IN ST B13 (GIS-BMP-
8286) IS AT 0% OF ITS CAPACITY
3. DIVERSION STRUCTURE IN ST H6 IS
CLEAR
4. HDS UNIT IN ST H15 (GIS-BMP-
8301) IS AT 6.25% OF ITS CAPACITY
5. 1.125” OF SEDIMENT MEASURED IN
ISOLATOR ROW (GIS-BMP-8292)
6. OUTFALL STRUCTURE ST H4 SHOWS
STORMTECH DISCHARGE IS CLEAR
7. VIEW OF BIODETENTION BASIN 03A
(GIS-BMP-8293)
8. FILL ANIMAL BURROW AT NORTH
END OF BASIN 03A
9. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 03A
10. RIP RAP PUSHES WATER TO THE
SE EMBANKMENT OF BASIN 03A
11. VIEW OF ST H13 SHOWING NO
UNDERDRAIN DISCHARGE
12.DETERIORATION OF CONCRETE IN
PARKING LOT ABOVE BASIN 03A
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
13. VIEW OF BIODETENTION BASIN
02D (GIS-BMP-8285)
14. DEAD PLANT MATERIAL WAS CUT
DOWN AND REMOVED
15. ADD NATIVE PLANTS TO BARE
AREAS IN BIODETENTION BASIN 03A
16.SURFACE OF BASIN REMAINS
POROUS
17. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 02D
18. VIEW OF ST B5 SHOWING NO
UNDERDRAIN DISCHARGE
19. VIEW OF SURFACE DETENTION
BASIN (GIS-BMP-8278)
20. INVASIVE GROWTH IN SURFACE
DETENTION BASIN WAS MANAGED
21. EXPAND DEER EXCLUSION WRAPS
IN SURFACE DETENTION BASIN
22. CONCRETE FOUNDATION
AROUND STANDPIPE IS NOT LEVEL
23. SLIGHT PONDING AROUND
PERFORATED STANDPIPE
24. OUTFALL STRUCTURE ST A1 IS
CLEAR
Post-Construction Stormwater BMP Inspection and Maintenance Record
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
Address:700 Chesterfield Parkway West 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
Constr. Approval:May 19, 2017 Phone:(314) 229-8334
Record Start Date:June 19, 2017 E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
2 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)
2 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)F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
1 DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2017.06.19 Initial Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
2018.09.10 Inspection
2018.12.11 Inspection
2019.03.11 Inspection
2019.06.13 Inspection
2019.09.17 Inspection
2019.12.11 Inspection
2020.01.22 Maintenance HDS Unit
2020.03.05 Inspection
2020.06.23 Inspection
2020.09.16 Inspection
2020.12.08 Inspection
2021.03.16 Inspection
2021.06.08 Inspection
2021.09.08 Inspection
2021.12.07 Inspection
2022.03.02 Inspection
2022.06.22 Inspection
2022.09.22 Inspection
2022.11.09 Maintenance HDS Unit ST H15
2022.12.07 Inspection
2023.03.07 Inspection
2023.06.07 Inspection
2023.09.20 Inspection
2023.09.21 Maintenance HDS Unit ST B13
2023.12.06 Inspection
6
Post-Construction Stormwater BMP Inspection Report
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
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:
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D (GIS-BMP-8285)
Biodetention Basin 03A (GIS-BMP-8293)
Surface Detention System (GIS-BMP-8278)
Surface Detention System (GIS-BMP-8278)
Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Action Items Identified During This Inspection:
Biodetention Basin 03A (GIS-BMP-8293)
Page 1
Customer:
Contact:
Phone Number:
Email:
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 the Greenhouse Modernization and Expansion was approved by MSD on May 19, 2017 and includes two hydrodynamic separators that
serve as pretreatment for two biodetention basins, a Stormtech underground stormwater detention basin, and a surface detention basin, as well as
associated private inlets, manholes and piping. The HDS pretreatment was not entirely effective at removing fine particles of silt and clay washing into the
system while the drainage areas of the BMPs were not yet established, and so these materials instead were deposited on the surface of the biodetention
basins. Silt was removed by hand in March 2018 and the drainage areas of these BMPs now appear to have been stabilized with vegetation. The HDS unit
in ST H15 was maintained in January 2020 and September 2023 and in B13 was maintained in November 2022. Therefore, after carefully reviewing each
component of the system and finding only routine maintenance items to be addressed (see below), I can continue to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with its design intent.
CONTROL for growth of invasive weeds (Bayer) --- COMPLETED
CUT AND REMOVE dead plant material before next growing season (Bayer) --- COMPLETED
EXPAND deer exclusion wraps on trees at south end of basin (Bayer) --- NOT COMPLETED
ADD native plants to bare areas of basin (Bayer) --- IN PROGRESS
ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED
VACUUM AND PRESSURE WASH to remove sediment (Bayer) --- COMPLETED
CONTROL for invasive growth in rip rap swale (Bayer) --- COMPLETED
FILL animal burrow at north end of basin, photo 8 (Bayer)
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Diversion Structure in ST B7
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 02D (GIS-BMP-8285)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Diversion Structure in ST H6
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST H15 (GIS-BMP-8301)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 03A (GIS-BMP-8293)
Assessment Comments
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Green
Green
Green
Green
Bayer Greenhouse Modernization - December 6, 2023 Page 2
Max. depth recommended by manufacturer = 2'-0" HDS unit was vacuumed and pressured washed in November 2022, photo 2
Turf No turf; Native plants grasses on embankments were cut down & removed, photo 7
Plants Good coverage of native plants on surface; dead plant growth was removed, photo 7
Weeds Invasive growth was removed during 2023 growing season
Underdrain Underdrain is clear and dry; no discharge observed at ST H13, photo 11
Condition of filter media Filter media is in good condition, photo 9
Mulch Mulch is covering all embankments
Maintenance due when 75% of Max. depth is exceeded Maintenance is needed according to manufacturer's O & M Manual
Attribute
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 7
Clogging No indications of clogging
Water ponding on surface No ponding water
Animal activity FILL animal burrow at north end of basin, photo 8 (Bayer)
Inlet Rock blanket below FES Inlet is above flowline, pushing water to the SE embankment
Erosion MONITOR further scouring of embankment to the southeast of FES inlet, photo 10
Sediment No sediment visible on surface of filter bed, photo 9
Distance from rim to bottom =10'-6" HDS unit was maintained in January 2020 & September 2023
Depth of sediment =0'-1.5" Increase of 1.5" of sediment since September 2023 inspection
Sheen on water surface No sheen
Odor No odor
Structural components Coupling is askew between HDS unit and outlet**
Structural components Clear, photo 3
Trash/debris/sediment Some sediment and gravel in bottom of structure
Distance from rim to sediment =10'-6"
Attribute
Access
Trash/debris/leaves No trash, debris or leaves
Underdrain Underdrain is clear and dry; no discharge observed at ST B5, photo 18
Structural components - ST B5 Clear, photo 18
Condition of filter media Filter media is in good condition, photo 17
Animal activity No further scouring of southeast quadrant of basin
Plants ADD native plants to bare areas of basin, photo 15 (Bayer)
Weeds Invasive growth was removed during 2023 growing season
Attribute
Erosion No erosion noted
Sediment No silt visible on surface of basin
Mulch Mulch is covering south embankment
Water ponding on surface No ponding water
Sheen on water surface N/A
Odor None
Attribute
Access Access is in a mulched landscaping bed
Trash/debris/leaves Some mulch collecting on surface of unit - inevitable due to access
Structural components Clear, photo 1
Trash/debris/sediment
Max. depth recommended by manufacturer = 2'-0" HDS unit is at 6.25% of capacity, photo 4
Distance from rim to sediment =12'-3.5"
Distance from rim to bottom =12'-3.5" No change since November 2022 maintenance
Depth of sediment =0'-0" HDS unit is at 0% of capacity, photo 2
Sheen on water surface No sheen on water surface
Odor No odor
Structural components Coupling is maintaining proper connection between HDS unit and outlet, photo 2
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 13
Clogging No indications of clogging
Maintenance due when 75% of Max. depth is exceeded Maintenance is not needed according to manufacturer's O & M Manual
Post-Construction Stormwater BMP Inspection Report
Assessment Comments
Green
Green
Green
Green
Green
Green
Outfall Structure in ST H4
Assessment Comments
Green
Green
Green
Green
Surface Detention System (GIS-BMP-8278)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Outfall Structure in ST A1
Assessment Comments
Green
Green
Green
Green
Private Inlets/Manholes/Piping
Assessment Comments
Green
Green
Green
Green
Inspector's Notes
Bayer Greenhouse Modernization - December 6, 2023 Page 3
Water ponding on surface No ponding water
Erosion No further erosion below inlet
Native trees EXPAND deer exclusion wraps on trees at south end of basin, photo 21 (Bayer)
None
Sediment buildup on basin bottom
Attribute
Access
Trash/debris/leaves No trash, debris or leaves, photo 19
Sediment buildup at low flow orifice 1.5" of silt noted around concrete foundation of standpipe
Sediment buildup in pipes
Sediment buildup at low flow orifice None, photo 6
Structural components Clear
No sediment visible on basin bottom
Erosion Degradation of concrete seams in parking lot above basin 03A, photo 12
Turf Turf throughout basin is in good condition
Native trees Bald cypress trees are losing their leaves
Weeds Invasive growth in rip rap swale was managed during the growing season, photo 20
Access
Attribute
Access
Trash/debris/leaves EOP is clear of sediment, debris and leaves
Underdrain N/A
Structural components No further shifting of concrete foundation of standpipe was noted, photo 22
Sediment buildup at low flow orifice Minimal
Structural components Clear, photo 24
Trash/debris/leaves
System discharge Clear, photo 24
Attribute
Attribute
Access
Trash/debris/leaves None
Water ponding on bottom No ponding water below access pipe
Structural components Foundation stone adjacent to access pipe is not level, holds some sediment and water
Structural components MONITOR separation in seam of eccentric header pipe
Average sediment buildup 0.125 - 0.5" of sediment appears to cover the entire row, photo 5
Measured sediment buildup 1.125" of sediment measured at inspection port on 6/7/2023, photo 5
Stormtech Underground Stormwater Detention System in ST H5 (GIS-BMP-8292)
Attribute
Access Thigh or chest waders needed, at least 3' water in ST H5
IMPORTANT NOTE ABOUT PLANT MATERIALS IN STORMWATER QUALITY SYSTEMS
Dead plant and other organic materials, if allowed to lay on the surface of your stormwater quality filter(s) for an extended period, will decay and cause
premature clogging. Often, removal and replacement of some or all of the filter media and plant materials are required to restore full functionality. Removal
of dead plant materials and other organics each fall will extend the life of the stormwater quality system and reduce maintenance and repair costs.
If you have questions about plant maintenance or would like to develop a stewardship program to protect your stormwater quality assets, please let me
know.
June 7, 2023: Invasive growth in both biodetention basins, and in the rip rap swale of the surface detention basin, should continue to be managed. Timing
is not appropriate for adding more native plants to biodetention basin 02D, but arrangements should be made for doing this in the fall or spring. The
landscaping mesh around the trees in the surface detention basin need to be expanded - they are cutting into the tree bark. The HDS unit in ST H15 at
biodetention basin 03A has exceeded 75% of its capacity and therefore needs to be cleanout out.
September 20, 2023: Stormwater continues to scour the embankment to the southeast of the inlet in biodetention basin 03A. Some weeds noted during
the previous inspection seem to have been removed, but more weedy growth remains in the biodetention basins. The HDS unit was vacuumed and
pressure washed on 9/21/2023.
December 6, 2023: Dead plant growth was removed from the biodetention basins. Removal of dead plant growth revealed a new animal burrow at the
north end of biodetention basin 03A. An increase of 1.5" of sediment was measured in the HDS unit at ST H15. Gravel in the diversion structure and in
grate inlets in the parking lot above biodetention basin 03A show some gravel, which could perhaps be from the deterioration of the concrete seams in the
parking lot.
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
1. DIVERSION STRUCTURE IN ST B7 IS
CLEAR
2. HDS UNIT IN ST B13 (GIS-BMP-
8286) IS AT 0% OF ITS CAPACITY
3. DIVERSION STRUCTURE IN ST H6 IS
CLEAR
4. HDS UNIT IN ST H15 (GIS-BMP-
8301) IS AT 6.25% OF ITS CAPACITY
5. 1.125” OF SEDIMENT MEASURED IN
ISOLATOR ROW (GIS-BMP-8292)
6. OUTFALL STRUCTURE ST H4 SHOWS
STORMTECH DISCHARGE IS CLEAR
7. VIEW OF BIODETENTION BASIN 03A
(GIS-BMP-8293)
8. FILL ANIMAL BURROW AT NORTH
END OF BASIN 03A
9. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 03A
10. RIP RAP PUSHES WATER TO THE
SE EMBANKMENT OF BASIN 03A
11. VIEW OF ST H13 SHOWING NO
UNDERDRAIN DISCHARGE
12.DETERIORATION OF CONCRETE IN
PARKING LOT ABOVE BASIN 03A
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
13. VIEW OF BIODETENTION BASIN
02D (GIS-BMP-8285)
14. DEAD PLANT MATERIAL WAS CUT
DOWN AND REMOVED
15. ADD NATIVE PLANTS TO BARE
AREAS IN BIODETENTION BASIN 03A
16.SURFACE OF BASIN REMAINS
POROUS
17. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 02D
18. VIEW OF ST B5 SHOWING NO
UNDERDRAIN DISCHARGE
19. VIEW OF SURFACE DETENTION
BASIN (GIS-BMP-8278)
20. INVASIVE GROWTH IN SURFACE
DETENTION BASIN WAS MANAGED
21. EXPAND DEER EXCLUSION WRAPS
IN SURFACE DETENTION BASIN
22. CONCRETE FOUNDATION
AROUND STANDPIPE IS NOT LEVEL
23. SLIGHT PONDING AROUND
PERFORATED STANDPIPE
24. OUTFALL STRUCTURE ST A1 IS
CLEAR
Post-Construction Stormwater BMP Inspection and Maintenance Record
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
Address:700 Chesterfield Parkway West 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
Constr. Approval:May 19, 2017 Phone:(314) 229-8334
Record Start Date:June 19, 2017 E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
2 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)
2 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)F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
1 DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2017.06.19 Initial Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
2018.09.10 Inspection
2018.12.11 Inspection
2019.03.11 Inspection
2019.06.13 Inspection
2019.09.17 Inspection
2019.12.11 Inspection
2020.01.22 Maintenance HDS Unit
2020.03.05 Inspection
2020.06.23 Inspection
2020.09.16 Inspection
2020.12.08 Inspection
2021.03.16 Inspection
2021.06.08 Inspection
2021.09.08 Inspection
2021.12.07 Inspection
2022.03.02 Inspection
2022.06.22 Inspection
2022.09.22 Inspection
2022.11.09 Maintenance HDS Unit ST H15
2022.12.07 Inspection
2023.03.07 Inspection
2023.06.07 Inspection
2023.09.20 Inspection
2023.09.21 Maintenance HDS Unit ST B13
2023.12.06 Inspection
6
Post-Construction Stormwater BMP Inspection Report
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
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:
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D (GIS-BMP-8285)
Biodetention Basin 03A (GIS-BMP-8293)
Surface Detention System (GIS-BMP-8278)
Surface Detention System (GIS-BMP-8278)
Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Action Items Identified During This Inspection:
Biodetention Basin 03A (GIS-BMP-8293)
Page 1
Customer:
Contact:
Phone Number:
Email:
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 the Greenhouse Modernization and Expansion was approved by MSD on May 19, 2017 and includes two hydrodynamic separators that
serve as pretreatment for two biodetention basins, a Stormtech underground stormwater detention basin, and a surface detention basin, as well as
associated private inlets, manholes and piping. The HDS pretreatment was not entirely effective at removing fine particles of silt and clay washing into the
system while the drainage areas of the BMPs were not yet established, and so these materials instead were deposited on the surface of the biodetention
basins. Silt was removed by hand in March 2018 and the drainage areas of these BMPs now appear to have been stabilized with vegetation. The HDS unit
in ST H15 was maintained in January 2020 and September 2023 and in B13 was maintained in November 2022. Therefore, after carefully reviewing each
component of the system and finding only routine maintenance items to be addressed (see below), I can continue to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with its design intent.
CONTROL for growth of invasive weeds (Bayer) --- COMPLETED
CUT AND REMOVE dead plant material before next growing season (Bayer) --- COMPLETED
EXPAND deer exclusion wraps on trees at south end of basin (Bayer) --- NOT COMPLETED
ADD native plants to bare areas of basin (Bayer) --- IN PROGRESS
ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED
VACUUM AND PRESSURE WASH to remove sediment (Bayer) --- COMPLETED
CONTROL for invasive growth in rip rap swale (Bayer) --- COMPLETED
FILL animal burrow at north end of basin, photo 8 (Bayer)
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Diversion Structure in ST B7
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 02D (GIS-BMP-8285)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Diversion Structure in ST H6
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST H15 (GIS-BMP-8301)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 03A (GIS-BMP-8293)
Assessment Comments
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Green
Green
Green
Green
Bayer Greenhouse Modernization - December 6, 2023 Page 2
Max. depth recommended by manufacturer = 2'-0" HDS unit was vacuumed and pressured washed in November 2022, photo 2
Turf No turf; Native plants grasses on embankments were cut down & removed, photo 7
Plants Good coverage of native plants on surface; dead plant growth was removed, photo 7
Weeds Invasive growth was removed during 2023 growing season
Underdrain Underdrain is clear and dry; no discharge observed at ST H13, photo 11
Condition of filter media Filter media is in good condition, photo 9
Mulch Mulch is covering all embankments
Maintenance due when 75% of Max. depth is exceeded Maintenance is needed according to manufacturer's O & M Manual
Attribute
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 7
Clogging No indications of clogging
Water ponding on surface No ponding water
Animal activity FILL animal burrow at north end of basin, photo 8 (Bayer)
Inlet Rock blanket below FES Inlet is above flowline, pushing water to the SE embankment
Erosion MONITOR further scouring of embankment to the southeast of FES inlet, photo 10
Sediment No sediment visible on surface of filter bed, photo 9
Distance from rim to bottom =10'-6" HDS unit was maintained in January 2020 & September 2023
Depth of sediment =0'-1.5" Increase of 1.5" of sediment since September 2023 inspection
Sheen on water surface No sheen
Odor No odor
Structural components Coupling is askew between HDS unit and outlet**
Structural components Clear, photo 3
Trash/debris/sediment Some sediment and gravel in bottom of structure
Distance from rim to sediment =10'-6"
Attribute
Access
Trash/debris/leaves No trash, debris or leaves
Underdrain Underdrain is clear and dry; no discharge observed at ST B5, photo 18
Structural components - ST B5 Clear, photo 18
Condition of filter media Filter media is in good condition, photo 17
Animal activity No further scouring of southeast quadrant of basin
Plants ADD native plants to bare areas of basin, photo 15 (Bayer)
Weeds Invasive growth was removed during 2023 growing season
Attribute
Erosion No erosion noted
Sediment No silt visible on surface of basin
Mulch Mulch is covering south embankment
Water ponding on surface No ponding water
Sheen on water surface N/A
Odor None
Attribute
Access Access is in a mulched landscaping bed
Trash/debris/leaves Some mulch collecting on surface of unit - inevitable due to access
Structural components Clear, photo 1
Trash/debris/sediment
Max. depth recommended by manufacturer = 2'-0" HDS unit is at 6.25% of capacity, photo 4
Distance from rim to sediment =12'-3.5"
Distance from rim to bottom =12'-3.5" No change since November 2022 maintenance
Depth of sediment =0'-0" HDS unit is at 0% of capacity, photo 2
Sheen on water surface No sheen on water surface
Odor No odor
Structural components Coupling is maintaining proper connection between HDS unit and outlet, photo 2
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 13
Clogging No indications of clogging
Maintenance due when 75% of Max. depth is exceeded Maintenance is not needed according to manufacturer's O & M Manual
Post-Construction Stormwater BMP Inspection Report
Assessment Comments
Green
Green
Green
Green
Green
Green
Outfall Structure in ST H4
Assessment Comments
Green
Green
Green
Green
Surface Detention System (GIS-BMP-8278)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Outfall Structure in ST A1
Assessment Comments
Green
Green
Green
Green
Private Inlets/Manholes/Piping
Assessment Comments
Green
Green
Green
Green
Inspector's Notes
Bayer Greenhouse Modernization - December 6, 2023 Page 3
Water ponding on surface No ponding water
Erosion No further erosion below inlet
Native trees EXPAND deer exclusion wraps on trees at south end of basin, photo 21 (Bayer)
None
Sediment buildup on basin bottom
Attribute
Access
Trash/debris/leaves No trash, debris or leaves, photo 19
Sediment buildup at low flow orifice 1.5" of silt noted around concrete foundation of standpipe
Sediment buildup in pipes
Sediment buildup at low flow orifice None, photo 6
Structural components Clear
No sediment visible on basin bottom
Erosion Degradation of concrete seams in parking lot above basin 03A, photo 12
Turf Turf throughout basin is in good condition
Native trees Bald cypress trees are losing their leaves
Weeds Invasive growth in rip rap swale was managed during the growing season, photo 20
Access
Attribute
Access
Trash/debris/leaves EOP is clear of sediment, debris and leaves
Underdrain N/A
Structural components No further shifting of concrete foundation of standpipe was noted, photo 22
Sediment buildup at low flow orifice Minimal
Structural components Clear, photo 24
Trash/debris/leaves
System discharge Clear, photo 24
Attribute
Attribute
Access
Trash/debris/leaves None
Water ponding on bottom No ponding water below access pipe
Structural components Foundation stone adjacent to access pipe is not level, holds some sediment and water
Structural components MONITOR separation in seam of eccentric header pipe
Average sediment buildup 0.125 - 0.5" of sediment appears to cover the entire row, photo 5
Measured sediment buildup 1.125" of sediment measured at inspection port on 6/7/2023, photo 5
Stormtech Underground Stormwater Detention System in ST H5 (GIS-BMP-8292)
Attribute
Access Thigh or chest waders needed, at least 3' water in ST H5
IMPORTANT NOTE ABOUT PLANT MATERIALS IN STORMWATER QUALITY SYSTEMS
Dead plant and other organic materials, if allowed to lay on the surface of your stormwater quality filter(s) for an extended period, will decay and cause
premature clogging. Often, removal and replacement of some or all of the filter media and plant materials are required to restore full functionality. Removal
of dead plant materials and other organics each fall will extend the life of the stormwater quality system and reduce maintenance and repair costs.
If you have questions about plant maintenance or would like to develop a stewardship program to protect your stormwater quality assets, please let me
know.
June 7, 2023: Invasive growth in both biodetention basins, and in the rip rap swale of the surface detention basin, should continue to be managed. Timing
is not appropriate for adding more native plants to biodetention basin 02D, but arrangements should be made for doing this in the fall or spring. The
landscaping mesh around the trees in the surface detention basin need to be expanded - they are cutting into the tree bark. The HDS unit in ST H15 at
biodetention basin 03A has exceeded 75% of its capacity and therefore needs to be cleanout out.
September 20, 2023: Stormwater continues to scour the embankment to the southeast of the inlet in biodetention basin 03A. Some weeds noted during
the previous inspection seem to have been removed, but more weedy growth remains in the biodetention basins. The HDS unit was vacuumed and
pressure washed on 9/21/2023.
December 6, 2023: Dead plant growth was removed from the biodetention basins. Removal of dead plant growth revealed a new animal burrow at the
north end of biodetention basin 03A. An increase of 1.5" of sediment was measured in the HDS unit at ST H15. Gravel in the diversion structure and in
grate inlets in the parking lot above biodetention basin 03A show some gravel, which could perhaps be from the deterioration of the concrete seams in the
parking lot.
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
1. DIVERSION STRUCTURE IN ST B7 IS
CLEAR
2. HDS UNIT IN ST B13 (GIS-BMP-
8286) IS AT 0% OF ITS CAPACITY
3. DIVERSION STRUCTURE IN ST H6 IS
CLEAR
4. HDS UNIT IN ST H15 (GIS-BMP-
8301) IS AT 6.25% OF ITS CAPACITY
5. 1.125” OF SEDIMENT MEASURED IN
ISOLATOR ROW (GIS-BMP-8292)
6. OUTFALL STRUCTURE ST H4 SHOWS
STORMTECH DISCHARGE IS CLEAR
7. VIEW OF BIODETENTION BASIN 03A
(GIS-BMP-8293)
8. FILL ANIMAL BURROW AT NORTH
END OF BASIN 03A
9. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 03A
10. RIP RAP PUSHES WATER TO THE
SE EMBANKMENT OF BASIN 03A
11. VIEW OF ST H13 SHOWING NO
UNDERDRAIN DISCHARGE
12.DETERIORATION OF CONCRETE IN
PARKING LOT ABOVE BASIN 03A
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
13. VIEW OF BIODETENTION BASIN
02D (GIS-BMP-8285)
14. DEAD PLANT MATERIAL WAS CUT
DOWN AND REMOVED
15. ADD NATIVE PLANTS TO BARE
AREAS IN BIODETENTION BASIN 03A
16.SURFACE OF BASIN REMAINS
POROUS
17. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 02D
18. VIEW OF ST B5 SHOWING NO
UNDERDRAIN DISCHARGE
19. VIEW OF SURFACE DETENTION
BASIN (GIS-BMP-8278)
20. INVASIVE GROWTH IN SURFACE
DETENTION BASIN WAS MANAGED
21. EXPAND DEER EXCLUSION WRAPS
IN SURFACE DETENTION BASIN
22. CONCRETE FOUNDATION
AROUND STANDPIPE IS NOT LEVEL
23. SLIGHT PONDING AROUND
PERFORATED STANDPIPE
24. OUTFALL STRUCTURE ST A1 IS
CLEAR
Post-Construction Stormwater BMP Inspection and Maintenance Record
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
Address:700 Chesterfield Parkway West 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
Constr. Approval:May 19, 2017 Phone:(314) 229-8334
Record Start Date:June 19, 2017 E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
2 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)
2 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)F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
1 DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2017.06.19 Initial Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
2018.09.10 Inspection
2018.12.11 Inspection
2019.03.11 Inspection
2019.06.13 Inspection
2019.09.17 Inspection
2019.12.11 Inspection
2020.01.22 Maintenance HDS Unit
2020.03.05 Inspection
2020.06.23 Inspection
2020.09.16 Inspection
2020.12.08 Inspection
2021.03.16 Inspection
2021.06.08 Inspection
2021.09.08 Inspection
2021.12.07 Inspection
2022.03.02 Inspection
2022.06.22 Inspection
2022.09.22 Inspection
2022.11.09 Maintenance HDS Unit ST H15
2022.12.07 Inspection
2023.03.07 Inspection
2023.06.07 Inspection
2023.09.20 Inspection
2023.09.21 Maintenance HDS Unit ST B13
2023.12.06 Inspection
6
Post-Construction Stormwater BMP Inspection Report
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
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:
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D (GIS-BMP-8285)
Biodetention Basin 03A (GIS-BMP-8293)
Surface Detention System (GIS-BMP-8278)
Surface Detention System (GIS-BMP-8278)
Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Action Items Identified During This Inspection:
Biodetention Basin 03A (GIS-BMP-8293)
Page 1
Customer:
Contact:
Phone Number:
Email:
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 the Greenhouse Modernization and Expansion was approved by MSD on May 19, 2017 and includes two hydrodynamic separators that
serve as pretreatment for two biodetention basins, a Stormtech underground stormwater detention basin, and a surface detention basin, as well as
associated private inlets, manholes and piping. The HDS pretreatment was not entirely effective at removing fine particles of silt and clay washing into the
system while the drainage areas of the BMPs were not yet established, and so these materials instead were deposited on the surface of the biodetention
basins. Silt was removed by hand in March 2018 and the drainage areas of these BMPs now appear to have been stabilized with vegetation. The HDS unit
in ST H15 was maintained in January 2020 and September 2023 and in B13 was maintained in November 2022. Therefore, after carefully reviewing each
component of the system and finding only routine maintenance items to be addressed (see below), I can continue to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with its design intent.
CONTROL for growth of invasive weeds (Bayer) --- COMPLETED
CUT AND REMOVE dead plant material before next growing season (Bayer) --- COMPLETED
EXPAND deer exclusion wraps on trees at south end of basin (Bayer) --- NOT COMPLETED
ADD native plants to bare areas of basin (Bayer) --- IN PROGRESS
ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED
VACUUM AND PRESSURE WASH to remove sediment (Bayer) --- COMPLETED
CONTROL for invasive growth in rip rap swale (Bayer) --- COMPLETED
FILL animal burrow at north end of basin, photo 8 (Bayer)
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Diversion Structure in ST B7
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 02D (GIS-BMP-8285)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Diversion Structure in ST H6
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST H15 (GIS-BMP-8301)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 03A (GIS-BMP-8293)
Assessment Comments
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Green
Green
Green
Green
Bayer Greenhouse Modernization - December 6, 2023 Page 2
Max. depth recommended by manufacturer = 2'-0" HDS unit was vacuumed and pressured washed in November 2022, photo 2
Turf No turf; Native plants grasses on embankments were cut down & removed, photo 7
Plants Good coverage of native plants on surface; dead plant growth was removed, photo 7
Weeds Invasive growth was removed during 2023 growing season
Underdrain Underdrain is clear and dry; no discharge observed at ST H13, photo 11
Condition of filter media Filter media is in good condition, photo 9
Mulch Mulch is covering all embankments
Maintenance due when 75% of Max. depth is exceeded Maintenance is needed according to manufacturer's O & M Manual
Attribute
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 7
Clogging No indications of clogging
Water ponding on surface No ponding water
Animal activity FILL animal burrow at north end of basin, photo 8 (Bayer)
Inlet Rock blanket below FES Inlet is above flowline, pushing water to the SE embankment
Erosion MONITOR further scouring of embankment to the southeast of FES inlet, photo 10
Sediment No sediment visible on surface of filter bed, photo 9
Distance from rim to bottom =10'-6" HDS unit was maintained in January 2020 & September 2023
Depth of sediment =0'-1.5" Increase of 1.5" of sediment since September 2023 inspection
Sheen on water surface No sheen
Odor No odor
Structural components Coupling is askew between HDS unit and outlet**
Structural components Clear, photo 3
Trash/debris/sediment Some sediment and gravel in bottom of structure
Distance from rim to sediment =10'-6"
Attribute
Access
Trash/debris/leaves No trash, debris or leaves
Underdrain Underdrain is clear and dry; no discharge observed at ST B5, photo 18
Structural components - ST B5 Clear, photo 18
Condition of filter media Filter media is in good condition, photo 17
Animal activity No further scouring of southeast quadrant of basin
Plants ADD native plants to bare areas of basin, photo 15 (Bayer)
Weeds Invasive growth was removed during 2023 growing season
Attribute
Erosion No erosion noted
Sediment No silt visible on surface of basin
Mulch Mulch is covering south embankment
Water ponding on surface No ponding water
Sheen on water surface N/A
Odor None
Attribute
Access Access is in a mulched landscaping bed
Trash/debris/leaves Some mulch collecting on surface of unit - inevitable due to access
Structural components Clear, photo 1
Trash/debris/sediment
Max. depth recommended by manufacturer = 2'-0" HDS unit is at 6.25% of capacity, photo 4
Distance from rim to sediment =12'-3.5"
Distance from rim to bottom =12'-3.5" No change since November 2022 maintenance
Depth of sediment =0'-0" HDS unit is at 0% of capacity, photo 2
Sheen on water surface No sheen on water surface
Odor No odor
Structural components Coupling is maintaining proper connection between HDS unit and outlet, photo 2
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 13
Clogging No indications of clogging
Maintenance due when 75% of Max. depth is exceeded Maintenance is not needed according to manufacturer's O & M Manual
Post-Construction Stormwater BMP Inspection Report
Assessment Comments
Green
Green
Green
Green
Green
Green
Outfall Structure in ST H4
Assessment Comments
Green
Green
Green
Green
Surface Detention System (GIS-BMP-8278)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Outfall Structure in ST A1
Assessment Comments
Green
Green
Green
Green
Private Inlets/Manholes/Piping
Assessment Comments
Green
Green
Green
Green
Inspector's Notes
Bayer Greenhouse Modernization - December 6, 2023 Page 3
Water ponding on surface No ponding water
Erosion No further erosion below inlet
Native trees EXPAND deer exclusion wraps on trees at south end of basin, photo 21 (Bayer)
None
Sediment buildup on basin bottom
Attribute
Access
Trash/debris/leaves No trash, debris or leaves, photo 19
Sediment buildup at low flow orifice 1.5" of silt noted around concrete foundation of standpipe
Sediment buildup in pipes
Sediment buildup at low flow orifice None, photo 6
Structural components Clear
No sediment visible on basin bottom
Erosion Degradation of concrete seams in parking lot above basin 03A, photo 12
Turf Turf throughout basin is in good condition
Native trees Bald cypress trees are losing their leaves
Weeds Invasive growth in rip rap swale was managed during the growing season, photo 20
Access
Attribute
Access
Trash/debris/leaves EOP is clear of sediment, debris and leaves
Underdrain N/A
Structural components No further shifting of concrete foundation of standpipe was noted, photo 22
Sediment buildup at low flow orifice Minimal
Structural components Clear, photo 24
Trash/debris/leaves
System discharge Clear, photo 24
Attribute
Attribute
Access
Trash/debris/leaves None
Water ponding on bottom No ponding water below access pipe
Structural components Foundation stone adjacent to access pipe is not level, holds some sediment and water
Structural components MONITOR separation in seam of eccentric header pipe
Average sediment buildup 0.125 - 0.5" of sediment appears to cover the entire row, photo 5
Measured sediment buildup 1.125" of sediment measured at inspection port on 6/7/2023, photo 5
Stormtech Underground Stormwater Detention System in ST H5 (GIS-BMP-8292)
Attribute
Access Thigh or chest waders needed, at least 3' water in ST H5
IMPORTANT NOTE ABOUT PLANT MATERIALS IN STORMWATER QUALITY SYSTEMS
Dead plant and other organic materials, if allowed to lay on the surface of your stormwater quality filter(s) for an extended period, will decay and cause
premature clogging. Often, removal and replacement of some or all of the filter media and plant materials are required to restore full functionality. Removal
of dead plant materials and other organics each fall will extend the life of the stormwater quality system and reduce maintenance and repair costs.
If you have questions about plant maintenance or would like to develop a stewardship program to protect your stormwater quality assets, please let me
know.
June 7, 2023: Invasive growth in both biodetention basins, and in the rip rap swale of the surface detention basin, should continue to be managed. Timing
is not appropriate for adding more native plants to biodetention basin 02D, but arrangements should be made for doing this in the fall or spring. The
landscaping mesh around the trees in the surface detention basin need to be expanded - they are cutting into the tree bark. The HDS unit in ST H15 at
biodetention basin 03A has exceeded 75% of its capacity and therefore needs to be cleanout out.
September 20, 2023: Stormwater continues to scour the embankment to the southeast of the inlet in biodetention basin 03A. Some weeds noted during
the previous inspection seem to have been removed, but more weedy growth remains in the biodetention basins. The HDS unit was vacuumed and
pressure washed on 9/21/2023.
December 6, 2023: Dead plant growth was removed from the biodetention basins. Removal of dead plant growth revealed a new animal burrow at the
north end of biodetention basin 03A. An increase of 1.5" of sediment was measured in the HDS unit at ST H15. Gravel in the diversion structure and in
grate inlets in the parking lot above biodetention basin 03A show some gravel, which could perhaps be from the deterioration of the concrete seams in the
parking lot.
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
1. DIVERSION STRUCTURE IN ST B7 IS
CLEAR
2. HDS UNIT IN ST B13 (GIS-BMP-
8286) IS AT 0% OF ITS CAPACITY
3. DIVERSION STRUCTURE IN ST H6 IS
CLEAR
4. HDS UNIT IN ST H15 (GIS-BMP-
8301) IS AT 6.25% OF ITS CAPACITY
5. 1.125” OF SEDIMENT MEASURED IN
ISOLATOR ROW (GIS-BMP-8292)
6. OUTFALL STRUCTURE ST H4 SHOWS
STORMTECH DISCHARGE IS CLEAR
7. VIEW OF BIODETENTION BASIN 03A
(GIS-BMP-8293)
8. FILL ANIMAL BURROW AT NORTH
END OF BASIN 03A
9. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 03A
10. RIP RAP PUSHES WATER TO THE
SE EMBANKMENT OF BASIN 03A
11. VIEW OF ST H13 SHOWING NO
UNDERDRAIN DISCHARGE
12.DETERIORATION OF CONCRETE IN
PARKING LOT ABOVE BASIN 03A
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
13. VIEW OF BIODETENTION BASIN
02D (GIS-BMP-8285)
14. DEAD PLANT MATERIAL WAS CUT
DOWN AND REMOVED
15. ADD NATIVE PLANTS TO BARE
AREAS IN BIODETENTION BASIN 03A
16.SURFACE OF BASIN REMAINS
POROUS
17. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 02D
18. VIEW OF ST B5 SHOWING NO
UNDERDRAIN DISCHARGE
19. VIEW OF SURFACE DETENTION
BASIN (GIS-BMP-8278)
20. INVASIVE GROWTH IN SURFACE
DETENTION BASIN WAS MANAGED
21. EXPAND DEER EXCLUSION WRAPS
IN SURFACE DETENTION BASIN
22. CONCRETE FOUNDATION
AROUND STANDPIPE IS NOT LEVEL
23. SLIGHT PONDING AROUND
PERFORATED STANDPIPE
24. OUTFALL STRUCTURE ST A1 IS
CLEAR
Post-Construction Stormwater BMP Inspection and Maintenance Record
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
Address:700 Chesterfield Parkway West 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
Constr. Approval:May 19, 2017 Phone:(314) 229-8334
Record Start Date:June 19, 2017 E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
2 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)
2 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)F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
1 DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2017.06.19 Initial Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
2018.09.10 Inspection
2018.12.11 Inspection
2019.03.11 Inspection
2019.06.13 Inspection
2019.09.17 Inspection
2019.12.11 Inspection
2020.01.22 Maintenance HDS Unit
2020.03.05 Inspection
2020.06.23 Inspection
2020.09.16 Inspection
2020.12.08 Inspection
2021.03.16 Inspection
2021.06.08 Inspection
2021.09.08 Inspection
2021.12.07 Inspection
2022.03.02 Inspection
2022.06.22 Inspection
2022.09.22 Inspection
2022.11.09 Maintenance HDS Unit ST H15
2022.12.07 Inspection
2023.03.07 Inspection
2023.06.07 Inspection
2023.09.20 Inspection
2023.09.21 Maintenance HDS Unit ST B13
2023.12.06 Inspection
6
Post-Construction Stormwater BMP Inspection Report
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
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:
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D (GIS-BMP-8285)
Biodetention Basin 03A (GIS-BMP-8293)
Surface Detention System (GIS-BMP-8278)
Surface Detention System (GIS-BMP-8278)
Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Action Items Identified During This Inspection:
Biodetention Basin 03A (GIS-BMP-8293)
Page 1
Customer:
Contact:
Phone Number:
Email:
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 the Greenhouse Modernization and Expansion was approved by MSD on May 19, 2017 and includes two hydrodynamic separators that
serve as pretreatment for two biodetention basins, a Stormtech underground stormwater detention basin, and a surface detention basin, as well as
associated private inlets, manholes and piping. The HDS pretreatment was not entirely effective at removing fine particles of silt and clay washing into the
system while the drainage areas of the BMPs were not yet established, and so these materials instead were deposited on the surface of the biodetention
basins. Silt was removed by hand in March 2018 and the drainage areas of these BMPs now appear to have been stabilized with vegetation. The HDS unit
in ST H15 was maintained in January 2020 and September 2023 and in B13 was maintained in November 2022. Therefore, after carefully reviewing each
component of the system and finding only routine maintenance items to be addressed (see below), I can continue to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with its design intent.
CONTROL for growth of invasive weeds (Bayer) --- COMPLETED
CUT AND REMOVE dead plant material before next growing season (Bayer) --- COMPLETED
EXPAND deer exclusion wraps on trees at south end of basin (Bayer) --- NOT COMPLETED
ADD native plants to bare areas of basin (Bayer) --- IN PROGRESS
ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED
VACUUM AND PRESSURE WASH to remove sediment (Bayer) --- COMPLETED
CONTROL for invasive growth in rip rap swale (Bayer) --- COMPLETED
FILL animal burrow at north end of basin, photo 8 (Bayer)
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Diversion Structure in ST B7
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 02D (GIS-BMP-8285)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Diversion Structure in ST H6
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST H15 (GIS-BMP-8301)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 03A (GIS-BMP-8293)
Assessment Comments
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Green
Green
Green
Green
Bayer Greenhouse Modernization - December 6, 2023 Page 2
Max. depth recommended by manufacturer = 2'-0" HDS unit was vacuumed and pressured washed in November 2022, photo 2
Turf No turf; Native plants grasses on embankments were cut down & removed, photo 7
Plants Good coverage of native plants on surface; dead plant growth was removed, photo 7
Weeds Invasive growth was removed during 2023 growing season
Underdrain Underdrain is clear and dry; no discharge observed at ST H13, photo 11
Condition of filter media Filter media is in good condition, photo 9
Mulch Mulch is covering all embankments
Maintenance due when 75% of Max. depth is exceeded Maintenance is needed according to manufacturer's O & M Manual
Attribute
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 7
Clogging No indications of clogging
Water ponding on surface No ponding water
Animal activity FILL animal burrow at north end of basin, photo 8 (Bayer)
Inlet Rock blanket below FES Inlet is above flowline, pushing water to the SE embankment
Erosion MONITOR further scouring of embankment to the southeast of FES inlet, photo 10
Sediment No sediment visible on surface of filter bed, photo 9
Distance from rim to bottom =10'-6" HDS unit was maintained in January 2020 & September 2023
Depth of sediment =0'-1.5" Increase of 1.5" of sediment since September 2023 inspection
Sheen on water surface No sheen
Odor No odor
Structural components Coupling is askew between HDS unit and outlet**
Structural components Clear, photo 3
Trash/debris/sediment Some sediment and gravel in bottom of structure
Distance from rim to sediment =10'-6"
Attribute
Access
Trash/debris/leaves No trash, debris or leaves
Underdrain Underdrain is clear and dry; no discharge observed at ST B5, photo 18
Structural components - ST B5 Clear, photo 18
Condition of filter media Filter media is in good condition, photo 17
Animal activity No further scouring of southeast quadrant of basin
Plants ADD native plants to bare areas of basin, photo 15 (Bayer)
Weeds Invasive growth was removed during 2023 growing season
Attribute
Erosion No erosion noted
Sediment No silt visible on surface of basin
Mulch Mulch is covering south embankment
Water ponding on surface No ponding water
Sheen on water surface N/A
Odor None
Attribute
Access Access is in a mulched landscaping bed
Trash/debris/leaves Some mulch collecting on surface of unit - inevitable due to access
Structural components Clear, photo 1
Trash/debris/sediment
Max. depth recommended by manufacturer = 2'-0" HDS unit is at 6.25% of capacity, photo 4
Distance from rim to sediment =12'-3.5"
Distance from rim to bottom =12'-3.5" No change since November 2022 maintenance
Depth of sediment =0'-0" HDS unit is at 0% of capacity, photo 2
Sheen on water surface No sheen on water surface
Odor No odor
Structural components Coupling is maintaining proper connection between HDS unit and outlet, photo 2
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 13
Clogging No indications of clogging
Maintenance due when 75% of Max. depth is exceeded Maintenance is not needed according to manufacturer's O & M Manual
Post-Construction Stormwater BMP Inspection Report
Assessment Comments
Green
Green
Green
Green
Green
Green
Outfall Structure in ST H4
Assessment Comments
Green
Green
Green
Green
Surface Detention System (GIS-BMP-8278)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Outfall Structure in ST A1
Assessment Comments
Green
Green
Green
Green
Private Inlets/Manholes/Piping
Assessment Comments
Green
Green
Green
Green
Inspector's Notes
Bayer Greenhouse Modernization - December 6, 2023 Page 3
Water ponding on surface No ponding water
Erosion No further erosion below inlet
Native trees EXPAND deer exclusion wraps on trees at south end of basin, photo 21 (Bayer)
None
Sediment buildup on basin bottom
Attribute
Access
Trash/debris/leaves No trash, debris or leaves, photo 19
Sediment buildup at low flow orifice 1.5" of silt noted around concrete foundation of standpipe
Sediment buildup in pipes
Sediment buildup at low flow orifice None, photo 6
Structural components Clear
No sediment visible on basin bottom
Erosion Degradation of concrete seams in parking lot above basin 03A, photo 12
Turf Turf throughout basin is in good condition
Native trees Bald cypress trees are losing their leaves
Weeds Invasive growth in rip rap swale was managed during the growing season, photo 20
Access
Attribute
Access
Trash/debris/leaves EOP is clear of sediment, debris and leaves
Underdrain N/A
Structural components No further shifting of concrete foundation of standpipe was noted, photo 22
Sediment buildup at low flow orifice Minimal
Structural components Clear, photo 24
Trash/debris/leaves
System discharge Clear, photo 24
Attribute
Attribute
Access
Trash/debris/leaves None
Water ponding on bottom No ponding water below access pipe
Structural components Foundation stone adjacent to access pipe is not level, holds some sediment and water
Structural components MONITOR separation in seam of eccentric header pipe
Average sediment buildup 0.125 - 0.5" of sediment appears to cover the entire row, photo 5
Measured sediment buildup 1.125" of sediment measured at inspection port on 6/7/2023, photo 5
Stormtech Underground Stormwater Detention System in ST H5 (GIS-BMP-8292)
Attribute
Access Thigh or chest waders needed, at least 3' water in ST H5
IMPORTANT NOTE ABOUT PLANT MATERIALS IN STORMWATER QUALITY SYSTEMS
Dead plant and other organic materials, if allowed to lay on the surface of your stormwater quality filter(s) for an extended period, will decay and cause
premature clogging. Often, removal and replacement of some or all of the filter media and plant materials are required to restore full functionality. Removal
of dead plant materials and other organics each fall will extend the life of the stormwater quality system and reduce maintenance and repair costs.
If you have questions about plant maintenance or would like to develop a stewardship program to protect your stormwater quality assets, please let me
know.
June 7, 2023: Invasive growth in both biodetention basins, and in the rip rap swale of the surface detention basin, should continue to be managed. Timing
is not appropriate for adding more native plants to biodetention basin 02D, but arrangements should be made for doing this in the fall or spring. The
landscaping mesh around the trees in the surface detention basin need to be expanded - they are cutting into the tree bark. The HDS unit in ST H15 at
biodetention basin 03A has exceeded 75% of its capacity and therefore needs to be cleanout out.
September 20, 2023: Stormwater continues to scour the embankment to the southeast of the inlet in biodetention basin 03A. Some weeds noted during
the previous inspection seem to have been removed, but more weedy growth remains in the biodetention basins. The HDS unit was vacuumed and
pressure washed on 9/21/2023.
December 6, 2023: Dead plant growth was removed from the biodetention basins. Removal of dead plant growth revealed a new animal burrow at the
north end of biodetention basin 03A. An increase of 1.5" of sediment was measured in the HDS unit at ST H15. Gravel in the diversion structure and in
grate inlets in the parking lot above biodetention basin 03A show some gravel, which could perhaps be from the deterioration of the concrete seams in the
parking lot.
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
1. DIVERSION STRUCTURE IN ST B7 IS
CLEAR
2. HDS UNIT IN ST B13 (GIS-BMP-
8286) IS AT 0% OF ITS CAPACITY
3. DIVERSION STRUCTURE IN ST H6 IS
CLEAR
4. HDS UNIT IN ST H15 (GIS-BMP-
8301) IS AT 6.25% OF ITS CAPACITY
5. 1.125” OF SEDIMENT MEASURED IN
ISOLATOR ROW (GIS-BMP-8292)
6. OUTFALL STRUCTURE ST H4 SHOWS
STORMTECH DISCHARGE IS CLEAR
7. VIEW OF BIODETENTION BASIN 03A
(GIS-BMP-8293)
8. FILL ANIMAL BURROW AT NORTH
END OF BASIN 03A
9. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 03A
10. RIP RAP PUSHES WATER TO THE
SE EMBANKMENT OF BASIN 03A
11. VIEW OF ST H13 SHOWING NO
UNDERDRAIN DISCHARGE
12.DETERIORATION OF CONCRETE IN
PARKING LOT ABOVE BASIN 03A
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
13. VIEW OF BIODETENTION BASIN
02D (GIS-BMP-8285)
14. DEAD PLANT MATERIAL WAS CUT
DOWN AND REMOVED
15. ADD NATIVE PLANTS TO BARE
AREAS IN BIODETENTION BASIN 03A
16.SURFACE OF BASIN REMAINS
POROUS
17. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 02D
18. VIEW OF ST B5 SHOWING NO
UNDERDRAIN DISCHARGE
19. VIEW OF SURFACE DETENTION
BASIN (GIS-BMP-8278)
20. INVASIVE GROWTH IN SURFACE
DETENTION BASIN WAS MANAGED
21. EXPAND DEER EXCLUSION WRAPS
IN SURFACE DETENTION BASIN
22. CONCRETE FOUNDATION
AROUND STANDPIPE IS NOT LEVEL
23. SLIGHT PONDING AROUND
PERFORATED STANDPIPE
24. OUTFALL STRUCTURE ST A1 IS
CLEAR
Post-Construction Stormwater BMP Inspection and Maintenance Record
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
Address:700 Chesterfield Parkway West 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
Constr. Approval:May 19, 2017 Phone:(314) 229-8334
Record Start Date:June 19, 2017 E-mail:marianne@stormwater-stl.net
Stormwater Treatment Facilities:Total Count:
Count Type Description Count Type Description
2 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)
2 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)F-PR PROPRIETARY BMP FILTER (U)
PPCO PERMEABLE PAVEMENT - CONCRETE (A)F-2 UNDERGROUND SAND FILTER (U)
PPGR PERMEABLE PAVEMENT - GRAVEL (A)
1 DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE
1 DET U UNDERGROUND FBAY PRETREATMENT FOREBAY
Inspection, Maintenance and Annual Report Submission Record:
Date Activity Date Activity
2017.06.19 Initial Inspection
2017.09.13 Inspection
2017.12.12 Inspection
2018.03.06 Inspection
2018.06.21 Inspection
2018.09.10 Inspection
2018.12.11 Inspection
2019.03.11 Inspection
2019.06.13 Inspection
2019.09.17 Inspection
2019.12.11 Inspection
2020.01.22 Maintenance HDS Unit
2020.03.05 Inspection
2020.06.23 Inspection
2020.09.16 Inspection
2020.12.08 Inspection
2021.03.16 Inspection
2021.06.08 Inspection
2021.09.08 Inspection
2021.12.07 Inspection
2022.03.02 Inspection
2022.06.22 Inspection
2022.09.22 Inspection
2022.11.09 Maintenance HDS Unit ST H15
2022.12.07 Inspection
2023.03.07 Inspection
2023.06.07 Inspection
2023.09.20 Inspection
2023.09.21 Maintenance HDS Unit ST B13
2023.12.06 Inspection
6
Post-Construction Stormwater BMP Inspection Report
Bayer Equip #:266290
MSD P Number:P001174327
Project:Greenhouse Modernization
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:
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D & 03A (GIS-BMP-8285 & -8293)
Biodetention Basin 02D (GIS-BMP-8285)
Biodetention Basin 03A (GIS-BMP-8293)
Surface Detention System (GIS-BMP-8278)
Surface Detention System (GIS-BMP-8278)
Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Action Items Identified During This Inspection:
Biodetention Basin 03A (GIS-BMP-8293)
Page 1
Customer:
Contact:
Phone Number:
Email:
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 the Greenhouse Modernization and Expansion was approved by MSD on May 19, 2017 and includes two hydrodynamic separators that
serve as pretreatment for two biodetention basins, a Stormtech underground stormwater detention basin, and a surface detention basin, as well as
associated private inlets, manholes and piping. The HDS pretreatment was not entirely effective at removing fine particles of silt and clay washing into the
system while the drainage areas of the BMPs were not yet established, and so these materials instead were deposited on the surface of the biodetention
basins. Silt was removed by hand in March 2018 and the drainage areas of these BMPs now appear to have been stabilized with vegetation. The HDS unit
in ST H15 was maintained in January 2020 and September 2023 and in B13 was maintained in November 2022. Therefore, after carefully reviewing each
component of the system and finding only routine maintenance items to be addressed (see below), I can continue to report:
Based on what was observed, this stormwater treatment system appears to be functioning in accordance with its design intent.
CONTROL for growth of invasive weeds (Bayer) --- COMPLETED
CUT AND REMOVE dead plant material before next growing season (Bayer) --- COMPLETED
EXPAND deer exclusion wraps on trees at south end of basin (Bayer) --- NOT COMPLETED
ADD native plants to bare areas of basin (Bayer) --- IN PROGRESS
ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED
VACUUM AND PRESSURE WASH to remove sediment (Bayer) --- COMPLETED
CONTROL for invasive growth in rip rap swale (Bayer) --- COMPLETED
FILL animal burrow at north end of basin, photo 8 (Bayer)
Post-Construction Stormwater BMP Inspection Report
Field Observations:
Diversion Structure in ST B7
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST B13 (GIS-BMP-8286)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 02D (GIS-BMP-8285)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Diversion Structure in ST H6
Attribute Assessment Comments
Green
Green
Downstream Defender Hydrodynamic Separator in ST H15 (GIS-BMP-8301)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Biodetention Basin 03A (GIS-BMP-8293)
Assessment Comments
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Green
Green
Green
Green
Bayer Greenhouse Modernization - December 6, 2023 Page 2
Max. depth recommended by manufacturer = 2'-0" HDS unit was vacuumed and pressured washed in November 2022, photo 2
Turf No turf; Native plants grasses on embankments were cut down & removed, photo 7
Plants Good coverage of native plants on surface; dead plant growth was removed, photo 7
Weeds Invasive growth was removed during 2023 growing season
Underdrain Underdrain is clear and dry; no discharge observed at ST H13, photo 11
Condition of filter media Filter media is in good condition, photo 9
Mulch Mulch is covering all embankments
Maintenance due when 75% of Max. depth is exceeded Maintenance is needed according to manufacturer's O & M Manual
Attribute
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 7
Clogging No indications of clogging
Water ponding on surface No ponding water
Animal activity FILL animal burrow at north end of basin, photo 8 (Bayer)
Inlet Rock blanket below FES Inlet is above flowline, pushing water to the SE embankment
Erosion MONITOR further scouring of embankment to the southeast of FES inlet, photo 10
Sediment No sediment visible on surface of filter bed, photo 9
Distance from rim to bottom =10'-6" HDS unit was maintained in January 2020 & September 2023
Depth of sediment =0'-1.5" Increase of 1.5" of sediment since September 2023 inspection
Sheen on water surface No sheen
Odor No odor
Structural components Coupling is askew between HDS unit and outlet**
Structural components Clear, photo 3
Trash/debris/sediment Some sediment and gravel in bottom of structure
Distance from rim to sediment =10'-6"
Attribute
Access
Trash/debris/leaves No trash, debris or leaves
Underdrain Underdrain is clear and dry; no discharge observed at ST B5, photo 18
Structural components - ST B5 Clear, photo 18
Condition of filter media Filter media is in good condition, photo 17
Animal activity No further scouring of southeast quadrant of basin
Plants ADD native plants to bare areas of basin, photo 15 (Bayer)
Weeds Invasive growth was removed during 2023 growing season
Attribute
Erosion No erosion noted
Sediment No silt visible on surface of basin
Mulch Mulch is covering south embankment
Water ponding on surface No ponding water
Sheen on water surface N/A
Odor None
Attribute
Access Access is in a mulched landscaping bed
Trash/debris/leaves Some mulch collecting on surface of unit - inevitable due to access
Structural components Clear, photo 1
Trash/debris/sediment
Max. depth recommended by manufacturer = 2'-0" HDS unit is at 6.25% of capacity, photo 4
Distance from rim to sediment =12'-3.5"
Distance from rim to bottom =12'-3.5" No change since November 2022 maintenance
Depth of sediment =0'-0" HDS unit is at 0% of capacity, photo 2
Sheen on water surface No sheen on water surface
Odor No odor
Structural components Coupling is maintaining proper connection between HDS unit and outlet, photo 2
Access
Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 13
Clogging No indications of clogging
Maintenance due when 75% of Max. depth is exceeded Maintenance is not needed according to manufacturer's O & M Manual
Post-Construction Stormwater BMP Inspection Report
Assessment Comments
Green
Green
Green
Green
Green
Green
Outfall Structure in ST H4
Assessment Comments
Green
Green
Green
Green
Surface Detention System (GIS-BMP-8278)
Assessment Comments
Green
Green
Green
Green
Green
Green
Green
Yellow
Green
Green
Green
Green
Green
Outfall Structure in ST A1
Assessment Comments
Green
Green
Green
Green
Private Inlets/Manholes/Piping
Assessment Comments
Green
Green
Green
Green
Inspector's Notes
Bayer Greenhouse Modernization - December 6, 2023 Page 3
Water ponding on surface No ponding water
Erosion No further erosion below inlet
Native trees EXPAND deer exclusion wraps on trees at south end of basin, photo 21 (Bayer)
None
Sediment buildup on basin bottom
Attribute
Access
Trash/debris/leaves No trash, debris or leaves, photo 19
Sediment buildup at low flow orifice 1.5" of silt noted around concrete foundation of standpipe
Sediment buildup in pipes
Sediment buildup at low flow orifice None, photo 6
Structural components Clear
No sediment visible on basin bottom
Erosion Degradation of concrete seams in parking lot above basin 03A, photo 12
Turf Turf throughout basin is in good condition
Native trees Bald cypress trees are losing their leaves
Weeds Invasive growth in rip rap swale was managed during the growing season, photo 20
Access
Attribute
Access
Trash/debris/leaves EOP is clear of sediment, debris and leaves
Underdrain N/A
Structural components No further shifting of concrete foundation of standpipe was noted, photo 22
Sediment buildup at low flow orifice Minimal
Structural components Clear, photo 24
Trash/debris/leaves
System discharge Clear, photo 24
Attribute
Attribute
Access
Trash/debris/leaves None
Water ponding on bottom No ponding water below access pipe
Structural components Foundation stone adjacent to access pipe is not level, holds some sediment and water
Structural components MONITOR separation in seam of eccentric header pipe
Average sediment buildup 0.125 - 0.5" of sediment appears to cover the entire row, photo 5
Measured sediment buildup 1.125" of sediment measured at inspection port on 6/7/2023, photo 5
Stormtech Underground Stormwater Detention System in ST H5 (GIS-BMP-8292)
Attribute
Access Thigh or chest waders needed, at least 3' water in ST H5
IMPORTANT NOTE ABOUT PLANT MATERIALS IN STORMWATER QUALITY SYSTEMS
Dead plant and other organic materials, if allowed to lay on the surface of your stormwater quality filter(s) for an extended period, will decay and cause
premature clogging. Often, removal and replacement of some or all of the filter media and plant materials are required to restore full functionality. Removal
of dead plant materials and other organics each fall will extend the life of the stormwater quality system and reduce maintenance and repair costs.
If you have questions about plant maintenance or would like to develop a stewardship program to protect your stormwater quality assets, please let me
know.
June 7, 2023: Invasive growth in both biodetention basins, and in the rip rap swale of the surface detention basin, should continue to be managed. Timing
is not appropriate for adding more native plants to biodetention basin 02D, but arrangements should be made for doing this in the fall or spring. The
landscaping mesh around the trees in the surface detention basin need to be expanded - they are cutting into the tree bark. The HDS unit in ST H15 at
biodetention basin 03A has exceeded 75% of its capacity and therefore needs to be cleanout out.
September 20, 2023: Stormwater continues to scour the embankment to the southeast of the inlet in biodetention basin 03A. Some weeds noted during
the previous inspection seem to have been removed, but more weedy growth remains in the biodetention basins. The HDS unit was vacuumed and
pressure washed on 9/21/2023.
December 6, 2023: Dead plant growth was removed from the biodetention basins. Removal of dead plant growth revealed a new animal burrow at the
north end of biodetention basin 03A. An increase of 1.5" of sediment was measured in the HDS unit at ST H15. Gravel in the diversion structure and in
grate inlets in the parking lot above biodetention basin 03A show some gravel, which could perhaps be from the deterioration of the concrete seams in the
parking lot.
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
1. DIVERSION STRUCTURE IN ST B7 IS
CLEAR
2. HDS UNIT IN ST B13 (GIS-BMP-
8286) IS AT 0% OF ITS CAPACITY
3. DIVERSION STRUCTURE IN ST H6 IS
CLEAR
4. HDS UNIT IN ST H15 (GIS-BMP-
8301) IS AT 6.25% OF ITS CAPACITY
5. 1.125” OF SEDIMENT MEASURED IN
ISOLATOR ROW (GIS-BMP-8292)
6. OUTFALL STRUCTURE ST H4 SHOWS
STORMTECH DISCHARGE IS CLEAR
7. VIEW OF BIODETENTION BASIN 03A
(GIS-BMP-8293)
8. FILL ANIMAL BURROW AT NORTH
END OF BASIN 03A
9. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 03A
10. RIP RAP PUSHES WATER TO THE
SE EMBANKMENT OF BASIN 03A
11. VIEW OF ST H13 SHOWING NO
UNDERDRAIN DISCHARGE
12.DETERIORATION OF CONCRETE IN
PARKING LOT ABOVE BASIN 03A
BAYER –
Greenhouse Expansion Stormwater BMP Photos
December 6, 2023
13. VIEW OF BIODETENTION BASIN
02D (GIS-BMP-8285)
14. DEAD PLANT MATERIAL WAS CUT
DOWN AND REMOVED
15. ADD NATIVE PLANTS TO BARE
AREAS IN BIODETENTION BASIN 03A
16.SURFACE OF BASIN REMAINS
POROUS
17. FILTER MEDIA IS IN GOOD
CONDITION IN BASIN 02D
18. VIEW OF ST B5 SHOWING NO
UNDERDRAIN DISCHARGE
19. VIEW OF SURFACE DETENTION
BASIN (GIS-BMP-8278)
20. INVASIVE GROWTH IN SURFACE
DETENTION BASIN WAS MANAGED
21. EXPAND DEER EXCLUSION WRAPS
IN SURFACE DETENTION BASIN
22. CONCRETE FOUNDATION
AROUND STANDPIPE IS NOT LEVEL
23. SLIGHT PONDING AROUND
PERFORATED STANDPIPE
24. OUTFALL STRUCTURE ST A1 IS
CLEAR