Loading...
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