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Home My Public Portal AboutP001174323_3/13/2024 4:38:13 PMPost-Construction Stormwater BMP Inspection and Maintenance Record Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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:January 18, 2019 Phone:(314) 229-8334 Record Start Date:June 21, 2018 E-mail:marianne@stormwater-stl.net Stormwater Treatment Facilities:Total Count: Count Type Description Count Type Description 4 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) 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) DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE 1 DET U UNDERGROUND 1 FBAY PRETREATMENT FOREBAY Inspection, Maintenance and Annual Report Submission Record: Date Activity Date Activity 2018.06.21 Initial 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 2020.03.05 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 2022.12.07 Inspection 2023.03.08 Inspection 2023.06.07 Inspection 2023.09.20 Inspection 2023.12.06 Inspection 6 Post-Construction Stormwater BMP Inspection Report Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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 Inspector(s):Marianne Pott Bayer Company:Stormwater STL LLC Anna Tang Address:6514 Lansdowne Avenue 63109 314-694-3169 Phone:(314) 229-8334 anna.tang@bayer.com 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: ALL Biodetention Basins ALL Biodetention Basins Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin 02C (GIS-BMP-9636) Biodetention Basin 02C (GIS-BMP-9636) System Discharge Action Items Identified During This Inspection: No action items were identified during this inspection. Page 1 REPAIR erosion at north edge of system discharge from ST F1 (Bayer) --- NOT COMPLETED FILL two animal burrows along north end of basin (Bayer) --- NOT COMPLETED 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. CONTROL for growth of invasive weeds (Bayer) --- COMPLETED Construction for the Parking Garage was approved by MSD on January 18, 2019 and includes four biodetention basins, one forebay, and one underground StormTech detention system along with associated private inlets, manholes, and piping. Biodetention basins 02A - 02C were further modified by the Visitor Parking project to the northwest. Grate Inlets ST4 and ST 3, part of the modifications, had picked up silt and debris during construction, which inspections showed was washing into biodetention basin 02A. The structures and piping from ST4 to ST 3 were cleaned during June 2020. Vegetation in all biodetention basins is managed as prescribed including cutting and removing for winter dormancy and managing unwanted growth periodically during the growing season. After carefully reviewing each component of the system and finding only routine maintenance needs to be addressed (see below), I can confirm: Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent. CUT AND REMOVE dead plant material before next spring (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- IN PROGRESS ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- NOT COMPLETED FILL in animal burrow and two sinkholes on embankments (Bayer) --- NOT COMPLETED REPLACE two broken standpipes at north end of the basin (Bayer) --- NOT COMPLETED FILL animal burrow at middle of west edge of basin (Bayer) --- NOT COMPLETED IMPROVE coverage of turf on northeast slope (Bayer) --- NOT COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED Post-Construction Stormwater BMP Inspection Report Field Observations: Diversion Structure in ST C2 Attribute Assessment Comments Green Green Pretreatment - Forebay (GIS-BMP-9634) Attribute Assessment Comments Green Green Green Green Green Green Green Green Green Green Green Green Green Biodetention Basin 01B (GIS-BMP-9634) Assessment Comments Green Green Green Green Green Green Yellow Green Green Green Yellow Green Yellow Green Green Assessment Comments Green Green Green Green Green Green Control Structure in ST F2 Assessment Comments Green Green Green Green Biodetention Basin 02A (GIS-BMP-8282) Assessment Comments Green Green Green Green Yellow Green Green Green Green Green Yellow Green Green Green Green Bayer EE Garage - December 6, 2023 Page 2 Water ponding on surface Small amount of ponding water in low spots Sheen on water surface None Clogging No indications of clogging Embankments Edges & embankments appear to be stable and remain vegetated Structural components Decorative rock lining has cracked plastic form at FES ST C12 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 1 Erosion Weeds Excessive foxtail growing on east embankment; weedy growth on surface is being treated Underdrain N/A Access Sediment Mulch No hardwood shredded mulch remaining on surface of basin Mulch N/A Attribute Turf Turf Plants Structural components Condition of filter media Water ponding on bottom Weeds Water ponding on surface Sheen on water surface Odor Sediment Perforated forebay outfalls were cleared of debris during the inspection No evidence of erosion on east embankment or anywhere else in forebay Up to 0.75" of sediment visible on river rock at low spots only Turf on embankments is in good condition ADD native plants to bare areas throughout biodetention basin (Bayer) IMPROVE coverage of turf on northeast slope, photo 2 (Bayer) Up to 0.125" of silt on surface at northeast perimeter from minor erosion of turf Turf on embankments is in good condition; some deterioration on northeast slope Nyloplast drain at ST F6 is clear of obstructions; underdrain end of pipe is not accessible Multiple probes confirm filter media is in good condition, photo 4 No ponding water Invasive growth was addressed during the 2023 growing season No ponding water Sufficient material in dry stream section below inlet covering fabric at scour None Underground StormTech Detention System (GIS-BMP-9637) Underdrain REPLACE two broken standpipes at north end of the basin, photo 3 (Bayer) Erosion No trash, debris or leaves noted Clogging Trash/debris/sediment Structural components Access Clear Trash/debris/leaves Trash/debris/leaves 1" of sediment in sump of ST F3 Sediment buildup in isolator row Approximately 67% of isolator row has 0.25 - 0.5" of sediment, photo 5 Sediment measured in isolator row Sediment measured at 1.25" below inspection port on 6/7/2023 inspection Attribute Access Manhole access at ST F3 and ST C1; ST C1 within 10 feet of beehives Attribute Access Trash/debris/leaves None Structural components Foundation stone appears to be level Attribute Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 6 Sediment buildup at low flow orifice None Structural components Clear, photo 23 Erosion No further scour at middle of north edge, but rock looks to have shifted, photo 8 Erosion Slight scouring of surface below ST E1 where water drains into basin Sediment No sediment visible on surface of basin Clogging No indications of clogging Water ponding on surface No ponding water Sheen on water surface FILL animal burrow at middle of west edge of basin (Bayer) Weeds Invasive growth was addressed during the 2023 growing season Underdrain ST D13 is clear of obstructions; no underdrain discharge is visible Structural components Sediment in rock blanket below ST E1 has stabilized since piping was cleaned Mulch Mulch is covering all embankments Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants ADD native plants to bare areas throughout biodetention basin, photos 6 & 7 (Bayer) Condition of filter media Multiple probes confirm filter media is in good condition Post-Construction Stormwater BMP Inspection Report Biodetention Basin O2B (GIS-BMP-8283) Assessment Comments Green Green Green Green Green Yellow Green Green Green Green Green Green Green Green Green Biodetention Basin 02C (GIS-BMP-9636) Assessment Comments Green Green Green Green Green Green Green Green Green Yellow Green Green Green Green Green Private Inlets/Manholes/Piping Assessment Comments Green Green Green Yellow Photographs See attached sheet(s) Inspector's Notes Bayer EE Garage - Bayer EE Garage - December 6, 2023 Page 3 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. March 8, 2023: Thick mulch was added around biodetention basins 02A - 02C. Basins were inspected during a light rain event. Native plants are starting to regrow. A lot of early spring season weeds were noted in biodetention basins 01B and 02A. The turf of the northeast embankment of biodetention basin 01B is deteriorating, likely from water existing the FES inlet above the sidewalk in the rip rap. Turf coverage on the embankment should be improved by adding compost to the embankment, reseeding with turf, and covering with seed germination blanket. June 7, 2023: Sediment has always been estimated as no more than 0.5 inches in the isolator row, looking up from the access manhole. Sediment was measured as 1.25" from the inspection port this visit. Invasive weeds should be removed periodically. Sediment is collecting in biodetention basin 02A below the inlet at ST E1. September 20, 2023: Invasive trumpet vine is spreading across the embankments and surface of biodetention basin O2B. December 6, 2023: Dead plant growth was removed. Standpipes are getting broken during the cut down and cleanup of vegetation during the winter. Standpipes need to be repaired to eliminate all openings below the level of the overflow structure. Munie representatives reached out to ask about planting plans and the recommended species. Adding native plants to bare spots is in progress. Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 11 Clogging No indications of clogging Attribute Erosion No further scouring noted around Nyloplast drain at ST D6 Sediment MONITOR for erosion under rock outlet Mulch Mulch is covering all embankments Water ponding on surface No ponding water Structural components Bottom of Nyloplast drain basin ST D6 is slightly cracked Animal burrow FILL two animal burrows along north end of basin, photo 12 (Bayer) Underdrain No underdrain discharge observed at ST D6 Structural components Nyloplast drain at ST D6 is clear of obstructions Condition of filter media Multiple probes confirm filter media is in good condition Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 11 Weeds Invasive growth was addressed during the 2023 growing season Underdrain Cleanout shows underdrain is dry and clear of obstructions Sediment Attribute Access Sediment - ST E4 to ST E3 Draining to Basin 02A Pipe was pressure washed and vacuumed to remove sediment Structural components No further sinkhole development at base of Nyloplast drain ST D8, photo 20 Condition of filter media Multiple probes confirm filter media is in good condition, photo 16 Erosion/settlement around structures System discharge REPAIR erosion at north edge of system discharge from ST F1, photo 24 (Bayer) MONITOR erosion on embankment to northwest of the rock outlet, photo 21 Mulch Mulch is covering all embankments Turf FILL in animal burrow and two sinkholes on embankments, photos 18 & 19 (Bayer) Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 15 Weeds Invasive growth was addressed during the 2023 growing season Sheen on water surface None Structural components Rock lining has crushed plastic FES form at ST G1, photo 22 Erosion Silt entering forebay from alongside pipe at STG1, photo 22 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 15 Clogging No indications of clogging Water ponding on surface No ponding water Attribute Access Decorative rock lining along building was repaired BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 1. VIEW OF BIODETENTION BASIN O1B (GIS- BMP-9634) 2. IMPROVE COVERAGE OF TURF ON NE EDGE OF BIODETENTION BASIN 01B 3. REPLACE TWO STANDPIPES AT NORTH END OF BIODETENTION BASIN 01B 4. FILTER MEDIA IS IN GOOD CONDITION – NO SEDIMENT PRESENT 5. VIEW OF ISOLATOR ROW WITH MINIMAL SEDIMENT (GIS-BMP-9637) 6. VIEW OF BIODETENTION BASIN 02A (GIS- BMP-8282) 7. ADD NATIVE PLANTS TO BARE AREAS OF BIODETENTION BASIN 02A 8. NO FURTHER SCOURING AT WALL OF BASIN 02A BUT ROCK HAS SHIFTED 9. SEDIMENT COLLECTING ON ROCK BLANKET OF BASIN 02A BELOW ST E1 10. MULCH IS COVERING ALL EMBANKMENTS 11. VIEW OF BIODETENTION BASIN 02B (GIS-BMP-8283) 12. FILL ANIMAL BURROWS AT NORTH END OF BASIN 02B BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 13. NO UNDERDRAIN DISCHARGE OBSERVED AT NYLOPLAST OVERFLOWS 14. DEAD PLANT MATERIAL WAS REMOVED FROM ALL BASINS 15. VIEW OF BIODETENTION BASIN 02C (GIS-BMP-9636) 16. SURFACE OF BIODETENTION BASIN 02C REMAINS VERY POROUS 17. SOIL HAS MORE SILT AND CLAY WHERE ERODING AT AT NW CORNER 18. FILL IN ANIMAL BURROW AT NORTHWEST CORNER IN BASIN 02C 19. FILL IN SINKHOLE ON SE EMBANKMENT OF BIODETENTION BASIN 02C 20. NO FURTHER SINKHOLE DEVELOPMENT AROUND ANY NYLOPLAST DRAINS 21. MONITOR EROSION ON EMBANKMENT TO NW OF THE ROCK OUTLET IN BASIN O2C 22. ROCK LINING HAS CRUSHED PLASTIC FES FORM AT INLET OF BASIN O2C 23. CONTROL STRUCTURE IN ST F2 SHOWS SYSTEM DISCHARGE TO BE CLEAR 24. REPAIR EROSION AT NORTH EDGE OF SYSTEM DISCHARGE FROM ST F1 Post-Construction Stormwater BMP Inspection and Maintenance Record Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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:January 18, 2019 Phone:(314) 229-8334 Record Start Date:June 21, 2018 E-mail:marianne@stormwater-stl.net Stormwater Treatment Facilities:Total Count: Count Type Description Count Type Description 4 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) 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) DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE 1 DET U UNDERGROUND 1 FBAY PRETREATMENT FOREBAY Inspection, Maintenance and Annual Report Submission Record: Date Activity Date Activity 2018.06.21 Initial 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 2020.03.05 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 2022.12.07 Inspection 2023.03.08 Inspection 2023.06.07 Inspection 2023.09.20 Inspection 2023.12.06 Inspection 6 Post-Construction Stormwater BMP Inspection Report Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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 Inspector(s):Marianne Pott Bayer Company:Stormwater STL LLC Anna Tang Address:6514 Lansdowne Avenue 63109 314-694-3169 Phone:(314) 229-8334 anna.tang@bayer.com 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: ALL Biodetention Basins ALL Biodetention Basins Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin 02C (GIS-BMP-9636) Biodetention Basin 02C (GIS-BMP-9636) System Discharge Action Items Identified During This Inspection: No action items were identified during this inspection. Page 1 REPAIR erosion at north edge of system discharge from ST F1 (Bayer) --- NOT COMPLETED FILL two animal burrows along north end of basin (Bayer) --- NOT COMPLETED 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. CONTROL for growth of invasive weeds (Bayer) --- COMPLETED Construction for the Parking Garage was approved by MSD on January 18, 2019 and includes four biodetention basins, one forebay, and one underground StormTech detention system along with associated private inlets, manholes, and piping. Biodetention basins 02A - 02C were further modified by the Visitor Parking project to the northwest. Grate Inlets ST4 and ST 3, part of the modifications, had picked up silt and debris during construction, which inspections showed was washing into biodetention basin 02A. The structures and piping from ST4 to ST 3 were cleaned during June 2020. Vegetation in all biodetention basins is managed as prescribed including cutting and removing for winter dormancy and managing unwanted growth periodically during the growing season. After carefully reviewing each component of the system and finding only routine maintenance needs to be addressed (see below), I can confirm: Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent. CUT AND REMOVE dead plant material before next spring (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- IN PROGRESS ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- NOT COMPLETED FILL in animal burrow and two sinkholes on embankments (Bayer) --- NOT COMPLETED REPLACE two broken standpipes at north end of the basin (Bayer) --- NOT COMPLETED FILL animal burrow at middle of west edge of basin (Bayer) --- NOT COMPLETED IMPROVE coverage of turf on northeast slope (Bayer) --- NOT COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED Post-Construction Stormwater BMP Inspection Report Field Observations: Diversion Structure in ST C2 Attribute Assessment Comments Green Green Pretreatment - Forebay (GIS-BMP-9634) Attribute Assessment Comments Green Green Green Green Green Green Green Green Green Green Green Green Green Biodetention Basin 01B (GIS-BMP-9634) Assessment Comments Green Green Green Green Green Green Yellow Green Green Green Yellow Green Yellow Green Green Assessment Comments Green Green Green Green Green Green Control Structure in ST F2 Assessment Comments Green Green Green Green Biodetention Basin 02A (GIS-BMP-8282) Assessment Comments Green Green Green Green Yellow Green Green Green Green Green Yellow Green Green Green Green Bayer EE Garage - December 6, 2023 Page 2 Water ponding on surface Small amount of ponding water in low spots Sheen on water surface None Clogging No indications of clogging Embankments Edges & embankments appear to be stable and remain vegetated Structural components Decorative rock lining has cracked plastic form at FES ST C12 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 1 Erosion Weeds Excessive foxtail growing on east embankment; weedy growth on surface is being treated Underdrain N/A Access Sediment Mulch No hardwood shredded mulch remaining on surface of basin Mulch N/A Attribute Turf Turf Plants Structural components Condition of filter media Water ponding on bottom Weeds Water ponding on surface Sheen on water surface Odor Sediment Perforated forebay outfalls were cleared of debris during the inspection No evidence of erosion on east embankment or anywhere else in forebay Up to 0.75" of sediment visible on river rock at low spots only Turf on embankments is in good condition ADD native plants to bare areas throughout biodetention basin (Bayer) IMPROVE coverage of turf on northeast slope, photo 2 (Bayer) Up to 0.125" of silt on surface at northeast perimeter from minor erosion of turf Turf on embankments is in good condition; some deterioration on northeast slope Nyloplast drain at ST F6 is clear of obstructions; underdrain end of pipe is not accessible Multiple probes confirm filter media is in good condition, photo 4 No ponding water Invasive growth was addressed during the 2023 growing season No ponding water Sufficient material in dry stream section below inlet covering fabric at scour None Underground StormTech Detention System (GIS-BMP-9637) Underdrain REPLACE two broken standpipes at north end of the basin, photo 3 (Bayer) Erosion No trash, debris or leaves noted Clogging Trash/debris/sediment Structural components Access Clear Trash/debris/leaves Trash/debris/leaves 1" of sediment in sump of ST F3 Sediment buildup in isolator row Approximately 67% of isolator row has 0.25 - 0.5" of sediment, photo 5 Sediment measured in isolator row Sediment measured at 1.25" below inspection port on 6/7/2023 inspection Attribute Access Manhole access at ST F3 and ST C1; ST C1 within 10 feet of beehives Attribute Access Trash/debris/leaves None Structural components Foundation stone appears to be level Attribute Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 6 Sediment buildup at low flow orifice None Structural components Clear, photo 23 Erosion No further scour at middle of north edge, but rock looks to have shifted, photo 8 Erosion Slight scouring of surface below ST E1 where water drains into basin Sediment No sediment visible on surface of basin Clogging No indications of clogging Water ponding on surface No ponding water Sheen on water surface FILL animal burrow at middle of west edge of basin (Bayer) Weeds Invasive growth was addressed during the 2023 growing season Underdrain ST D13 is clear of obstructions; no underdrain discharge is visible Structural components Sediment in rock blanket below ST E1 has stabilized since piping was cleaned Mulch Mulch is covering all embankments Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants ADD native plants to bare areas throughout biodetention basin, photos 6 & 7 (Bayer) Condition of filter media Multiple probes confirm filter media is in good condition Post-Construction Stormwater BMP Inspection Report Biodetention Basin O2B (GIS-BMP-8283) Assessment Comments Green Green Green Green Green Yellow Green Green Green Green Green Green Green Green Green Biodetention Basin 02C (GIS-BMP-9636) Assessment Comments Green Green Green Green Green Green Green Green Green Yellow Green Green Green Green Green Private Inlets/Manholes/Piping Assessment Comments Green Green Green Yellow Photographs See attached sheet(s) Inspector's Notes Bayer EE Garage - Bayer EE Garage - December 6, 2023 Page 3 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. March 8, 2023: Thick mulch was added around biodetention basins 02A - 02C. Basins were inspected during a light rain event. Native plants are starting to regrow. A lot of early spring season weeds were noted in biodetention basins 01B and 02A. The turf of the northeast embankment of biodetention basin 01B is deteriorating, likely from water existing the FES inlet above the sidewalk in the rip rap. Turf coverage on the embankment should be improved by adding compost to the embankment, reseeding with turf, and covering with seed germination blanket. June 7, 2023: Sediment has always been estimated as no more than 0.5 inches in the isolator row, looking up from the access manhole. Sediment was measured as 1.25" from the inspection port this visit. Invasive weeds should be removed periodically. Sediment is collecting in biodetention basin 02A below the inlet at ST E1. September 20, 2023: Invasive trumpet vine is spreading across the embankments and surface of biodetention basin O2B. December 6, 2023: Dead plant growth was removed. Standpipes are getting broken during the cut down and cleanup of vegetation during the winter. Standpipes need to be repaired to eliminate all openings below the level of the overflow structure. Munie representatives reached out to ask about planting plans and the recommended species. Adding native plants to bare spots is in progress. Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 11 Clogging No indications of clogging Attribute Erosion No further scouring noted around Nyloplast drain at ST D6 Sediment MONITOR for erosion under rock outlet Mulch Mulch is covering all embankments Water ponding on surface No ponding water Structural components Bottom of Nyloplast drain basin ST D6 is slightly cracked Animal burrow FILL two animal burrows along north end of basin, photo 12 (Bayer) Underdrain No underdrain discharge observed at ST D6 Structural components Nyloplast drain at ST D6 is clear of obstructions Condition of filter media Multiple probes confirm filter media is in good condition Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 11 Weeds Invasive growth was addressed during the 2023 growing season Underdrain Cleanout shows underdrain is dry and clear of obstructions Sediment Attribute Access Sediment - ST E4 to ST E3 Draining to Basin 02A Pipe was pressure washed and vacuumed to remove sediment Structural components No further sinkhole development at base of Nyloplast drain ST D8, photo 20 Condition of filter media Multiple probes confirm filter media is in good condition, photo 16 Erosion/settlement around structures System discharge REPAIR erosion at north edge of system discharge from ST F1, photo 24 (Bayer) MONITOR erosion on embankment to northwest of the rock outlet, photo 21 Mulch Mulch is covering all embankments Turf FILL in animal burrow and two sinkholes on embankments, photos 18 & 19 (Bayer) Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 15 Weeds Invasive growth was addressed during the 2023 growing season Sheen on water surface None Structural components Rock lining has crushed plastic FES form at ST G1, photo 22 Erosion Silt entering forebay from alongside pipe at STG1, photo 22 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 15 Clogging No indications of clogging Water ponding on surface No ponding water Attribute Access Decorative rock lining along building was repaired BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 1. VIEW OF BIODETENTION BASIN O1B (GIS- BMP-9634) 2. IMPROVE COVERAGE OF TURF ON NE EDGE OF BIODETENTION BASIN 01B 3. REPLACE TWO STANDPIPES AT NORTH END OF BIODETENTION BASIN 01B 4. FILTER MEDIA IS IN GOOD CONDITION – NO SEDIMENT PRESENT 5. VIEW OF ISOLATOR ROW WITH MINIMAL SEDIMENT (GIS-BMP-9637) 6. VIEW OF BIODETENTION BASIN 02A (GIS- BMP-8282) 7. ADD NATIVE PLANTS TO BARE AREAS OF BIODETENTION BASIN 02A 8. NO FURTHER SCOURING AT WALL OF BASIN 02A BUT ROCK HAS SHIFTED 9. SEDIMENT COLLECTING ON ROCK BLANKET OF BASIN 02A BELOW ST E1 10. MULCH IS COVERING ALL EMBANKMENTS 11. VIEW OF BIODETENTION BASIN 02B (GIS-BMP-8283) 12. FILL ANIMAL BURROWS AT NORTH END OF BASIN 02B BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 13. NO UNDERDRAIN DISCHARGE OBSERVED AT NYLOPLAST OVERFLOWS 14. DEAD PLANT MATERIAL WAS REMOVED FROM ALL BASINS 15. VIEW OF BIODETENTION BASIN 02C (GIS-BMP-9636) 16. SURFACE OF BIODETENTION BASIN 02C REMAINS VERY POROUS 17. SOIL HAS MORE SILT AND CLAY WHERE ERODING AT AT NW CORNER 18. FILL IN ANIMAL BURROW AT NORTHWEST CORNER IN BASIN 02C 19. FILL IN SINKHOLE ON SE EMBANKMENT OF BIODETENTION BASIN 02C 20. NO FURTHER SINKHOLE DEVELOPMENT AROUND ANY NYLOPLAST DRAINS 21. MONITOR EROSION ON EMBANKMENT TO NW OF THE ROCK OUTLET IN BASIN O2C 22. ROCK LINING HAS CRUSHED PLASTIC FES FORM AT INLET OF BASIN O2C 23. CONTROL STRUCTURE IN ST F2 SHOWS SYSTEM DISCHARGE TO BE CLEAR 24. REPAIR EROSION AT NORTH EDGE OF SYSTEM DISCHARGE FROM ST F1 Post-Construction Stormwater BMP Inspection and Maintenance Record Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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:January 18, 2019 Phone:(314) 229-8334 Record Start Date:June 21, 2018 E-mail:marianne@stormwater-stl.net Stormwater Treatment Facilities:Total Count: Count Type Description Count Type Description 4 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) 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) DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE 1 DET U UNDERGROUND 1 FBAY PRETREATMENT FOREBAY Inspection, Maintenance and Annual Report Submission Record: Date Activity Date Activity 2018.06.21 Initial 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 2020.03.05 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 2022.12.07 Inspection 2023.03.08 Inspection 2023.06.07 Inspection 2023.09.20 Inspection 2023.12.06 Inspection 6 Post-Construction Stormwater BMP Inspection Report Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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 Inspector(s):Marianne Pott Bayer Company:Stormwater STL LLC Anna Tang Address:6514 Lansdowne Avenue 63109 314-694-3169 Phone:(314) 229-8334 anna.tang@bayer.com 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: ALL Biodetention Basins ALL Biodetention Basins Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin 02C (GIS-BMP-9636) Biodetention Basin 02C (GIS-BMP-9636) System Discharge Action Items Identified During This Inspection: No action items were identified during this inspection. Page 1 REPAIR erosion at north edge of system discharge from ST F1 (Bayer) --- NOT COMPLETED FILL two animal burrows along north end of basin (Bayer) --- NOT COMPLETED 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. CONTROL for growth of invasive weeds (Bayer) --- COMPLETED Construction for the Parking Garage was approved by MSD on January 18, 2019 and includes four biodetention basins, one forebay, and one underground StormTech detention system along with associated private inlets, manholes, and piping. Biodetention basins 02A - 02C were further modified by the Visitor Parking project to the northwest. Grate Inlets ST4 and ST 3, part of the modifications, had picked up silt and debris during construction, which inspections showed was washing into biodetention basin 02A. The structures and piping from ST4 to ST 3 were cleaned during June 2020. Vegetation in all biodetention basins is managed as prescribed including cutting and removing for winter dormancy and managing unwanted growth periodically during the growing season. After carefully reviewing each component of the system and finding only routine maintenance needs to be addressed (see below), I can confirm: Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent. CUT AND REMOVE dead plant material before next spring (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- IN PROGRESS ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- NOT COMPLETED FILL in animal burrow and two sinkholes on embankments (Bayer) --- NOT COMPLETED REPLACE two broken standpipes at north end of the basin (Bayer) --- NOT COMPLETED FILL animal burrow at middle of west edge of basin (Bayer) --- NOT COMPLETED IMPROVE coverage of turf on northeast slope (Bayer) --- NOT COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED Post-Construction Stormwater BMP Inspection Report Field Observations: Diversion Structure in ST C2 Attribute Assessment Comments Green Green Pretreatment - Forebay (GIS-BMP-9634) Attribute Assessment Comments Green Green Green Green Green Green Green Green Green Green Green Green Green Biodetention Basin 01B (GIS-BMP-9634) Assessment Comments Green Green Green Green Green Green Yellow Green Green Green Yellow Green Yellow Green Green Assessment Comments Green Green Green Green Green Green Control Structure in ST F2 Assessment Comments Green Green Green Green Biodetention Basin 02A (GIS-BMP-8282) Assessment Comments Green Green Green Green Yellow Green Green Green Green Green Yellow Green Green Green Green Bayer EE Garage - December 6, 2023 Page 2 Water ponding on surface Small amount of ponding water in low spots Sheen on water surface None Clogging No indications of clogging Embankments Edges & embankments appear to be stable and remain vegetated Structural components Decorative rock lining has cracked plastic form at FES ST C12 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 1 Erosion Weeds Excessive foxtail growing on east embankment; weedy growth on surface is being treated Underdrain N/A Access Sediment Mulch No hardwood shredded mulch remaining on surface of basin Mulch N/A Attribute Turf Turf Plants Structural components Condition of filter media Water ponding on bottom Weeds Water ponding on surface Sheen on water surface Odor Sediment Perforated forebay outfalls were cleared of debris during the inspection No evidence of erosion on east embankment or anywhere else in forebay Up to 0.75" of sediment visible on river rock at low spots only Turf on embankments is in good condition ADD native plants to bare areas throughout biodetention basin (Bayer) IMPROVE coverage of turf on northeast slope, photo 2 (Bayer) Up to 0.125" of silt on surface at northeast perimeter from minor erosion of turf Turf on embankments is in good condition; some deterioration on northeast slope Nyloplast drain at ST F6 is clear of obstructions; underdrain end of pipe is not accessible Multiple probes confirm filter media is in good condition, photo 4 No ponding water Invasive growth was addressed during the 2023 growing season No ponding water Sufficient material in dry stream section below inlet covering fabric at scour None Underground StormTech Detention System (GIS-BMP-9637) Underdrain REPLACE two broken standpipes at north end of the basin, photo 3 (Bayer) Erosion No trash, debris or leaves noted Clogging Trash/debris/sediment Structural components Access Clear Trash/debris/leaves Trash/debris/leaves 1" of sediment in sump of ST F3 Sediment buildup in isolator row Approximately 67% of isolator row has 0.25 - 0.5" of sediment, photo 5 Sediment measured in isolator row Sediment measured at 1.25" below inspection port on 6/7/2023 inspection Attribute Access Manhole access at ST F3 and ST C1; ST C1 within 10 feet of beehives Attribute Access Trash/debris/leaves None Structural components Foundation stone appears to be level Attribute Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 6 Sediment buildup at low flow orifice None Structural components Clear, photo 23 Erosion No further scour at middle of north edge, but rock looks to have shifted, photo 8 Erosion Slight scouring of surface below ST E1 where water drains into basin Sediment No sediment visible on surface of basin Clogging No indications of clogging Water ponding on surface No ponding water Sheen on water surface FILL animal burrow at middle of west edge of basin (Bayer) Weeds Invasive growth was addressed during the 2023 growing season Underdrain ST D13 is clear of obstructions; no underdrain discharge is visible Structural components Sediment in rock blanket below ST E1 has stabilized since piping was cleaned Mulch Mulch is covering all embankments Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants ADD native plants to bare areas throughout biodetention basin, photos 6 & 7 (Bayer) Condition of filter media Multiple probes confirm filter media is in good condition Post-Construction Stormwater BMP Inspection Report Biodetention Basin O2B (GIS-BMP-8283) Assessment Comments Green Green Green Green Green Yellow Green Green Green Green Green Green Green Green Green Biodetention Basin 02C (GIS-BMP-9636) Assessment Comments Green Green Green Green Green Green Green Green Green Yellow Green Green Green Green Green Private Inlets/Manholes/Piping Assessment Comments Green Green Green Yellow Photographs See attached sheet(s) Inspector's Notes Bayer EE Garage - Bayer EE Garage - December 6, 2023 Page 3 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. March 8, 2023: Thick mulch was added around biodetention basins 02A - 02C. Basins were inspected during a light rain event. Native plants are starting to regrow. A lot of early spring season weeds were noted in biodetention basins 01B and 02A. The turf of the northeast embankment of biodetention basin 01B is deteriorating, likely from water existing the FES inlet above the sidewalk in the rip rap. Turf coverage on the embankment should be improved by adding compost to the embankment, reseeding with turf, and covering with seed germination blanket. June 7, 2023: Sediment has always been estimated as no more than 0.5 inches in the isolator row, looking up from the access manhole. Sediment was measured as 1.25" from the inspection port this visit. Invasive weeds should be removed periodically. Sediment is collecting in biodetention basin 02A below the inlet at ST E1. September 20, 2023: Invasive trumpet vine is spreading across the embankments and surface of biodetention basin O2B. December 6, 2023: Dead plant growth was removed. Standpipes are getting broken during the cut down and cleanup of vegetation during the winter. Standpipes need to be repaired to eliminate all openings below the level of the overflow structure. Munie representatives reached out to ask about planting plans and the recommended species. Adding native plants to bare spots is in progress. Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 11 Clogging No indications of clogging Attribute Erosion No further scouring noted around Nyloplast drain at ST D6 Sediment MONITOR for erosion under rock outlet Mulch Mulch is covering all embankments Water ponding on surface No ponding water Structural components Bottom of Nyloplast drain basin ST D6 is slightly cracked Animal burrow FILL two animal burrows along north end of basin, photo 12 (Bayer) Underdrain No underdrain discharge observed at ST D6 Structural components Nyloplast drain at ST D6 is clear of obstructions Condition of filter media Multiple probes confirm filter media is in good condition Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 11 Weeds Invasive growth was addressed during the 2023 growing season Underdrain Cleanout shows underdrain is dry and clear of obstructions Sediment Attribute Access Sediment - ST E4 to ST E3 Draining to Basin 02A Pipe was pressure washed and vacuumed to remove sediment Structural components No further sinkhole development at base of Nyloplast drain ST D8, photo 20 Condition of filter media Multiple probes confirm filter media is in good condition, photo 16 Erosion/settlement around structures System discharge REPAIR erosion at north edge of system discharge from ST F1, photo 24 (Bayer) MONITOR erosion on embankment to northwest of the rock outlet, photo 21 Mulch Mulch is covering all embankments Turf FILL in animal burrow and two sinkholes on embankments, photos 18 & 19 (Bayer) Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 15 Weeds Invasive growth was addressed during the 2023 growing season Sheen on water surface None Structural components Rock lining has crushed plastic FES form at ST G1, photo 22 Erosion Silt entering forebay from alongside pipe at STG1, photo 22 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 15 Clogging No indications of clogging Water ponding on surface No ponding water Attribute Access Decorative rock lining along building was repaired BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 1. VIEW OF BIODETENTION BASIN O1B (GIS- BMP-9634) 2. IMPROVE COVERAGE OF TURF ON NE EDGE OF BIODETENTION BASIN 01B 3. REPLACE TWO STANDPIPES AT NORTH END OF BIODETENTION BASIN 01B 4. FILTER MEDIA IS IN GOOD CONDITION – NO SEDIMENT PRESENT 5. VIEW OF ISOLATOR ROW WITH MINIMAL SEDIMENT (GIS-BMP-9637) 6. VIEW OF BIODETENTION BASIN 02A (GIS- BMP-8282) 7. ADD NATIVE PLANTS TO BARE AREAS OF BIODETENTION BASIN 02A 8. NO FURTHER SCOURING AT WALL OF BASIN 02A BUT ROCK HAS SHIFTED 9. SEDIMENT COLLECTING ON ROCK BLANKET OF BASIN 02A BELOW ST E1 10. MULCH IS COVERING ALL EMBANKMENTS 11. VIEW OF BIODETENTION BASIN 02B (GIS-BMP-8283) 12. FILL ANIMAL BURROWS AT NORTH END OF BASIN 02B BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 13. NO UNDERDRAIN DISCHARGE OBSERVED AT NYLOPLAST OVERFLOWS 14. DEAD PLANT MATERIAL WAS REMOVED FROM ALL BASINS 15. VIEW OF BIODETENTION BASIN 02C (GIS-BMP-9636) 16. SURFACE OF BIODETENTION BASIN 02C REMAINS VERY POROUS 17. SOIL HAS MORE SILT AND CLAY WHERE ERODING AT AT NW CORNER 18. FILL IN ANIMAL BURROW AT NORTHWEST CORNER IN BASIN 02C 19. FILL IN SINKHOLE ON SE EMBANKMENT OF BIODETENTION BASIN 02C 20. NO FURTHER SINKHOLE DEVELOPMENT AROUND ANY NYLOPLAST DRAINS 21. MONITOR EROSION ON EMBANKMENT TO NW OF THE ROCK OUTLET IN BASIN O2C 22. ROCK LINING HAS CRUSHED PLASTIC FES FORM AT INLET OF BASIN O2C 23. CONTROL STRUCTURE IN ST F2 SHOWS SYSTEM DISCHARGE TO BE CLEAR 24. REPAIR EROSION AT NORTH EDGE OF SYSTEM DISCHARGE FROM ST F1 Post-Construction Stormwater BMP Inspection and Maintenance Record Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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:January 18, 2019 Phone:(314) 229-8334 Record Start Date:June 21, 2018 E-mail:marianne@stormwater-stl.net Stormwater Treatment Facilities:Total Count: Count Type Description Count Type Description 4 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) 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) DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE 1 DET U UNDERGROUND 1 FBAY PRETREATMENT FOREBAY Inspection, Maintenance and Annual Report Submission Record: Date Activity Date Activity 2018.06.21 Initial 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 2020.03.05 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 2022.12.07 Inspection 2023.03.08 Inspection 2023.06.07 Inspection 2023.09.20 Inspection 2023.12.06 Inspection 6 Post-Construction Stormwater BMP Inspection Report Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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 Inspector(s):Marianne Pott Bayer Company:Stormwater STL LLC Anna Tang Address:6514 Lansdowne Avenue 63109 314-694-3169 Phone:(314) 229-8334 anna.tang@bayer.com 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: ALL Biodetention Basins ALL Biodetention Basins Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin 02C (GIS-BMP-9636) Biodetention Basin 02C (GIS-BMP-9636) System Discharge Action Items Identified During This Inspection: No action items were identified during this inspection. Page 1 REPAIR erosion at north edge of system discharge from ST F1 (Bayer) --- NOT COMPLETED FILL two animal burrows along north end of basin (Bayer) --- NOT COMPLETED 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. CONTROL for growth of invasive weeds (Bayer) --- COMPLETED Construction for the Parking Garage was approved by MSD on January 18, 2019 and includes four biodetention basins, one forebay, and one underground StormTech detention system along with associated private inlets, manholes, and piping. Biodetention basins 02A - 02C were further modified by the Visitor Parking project to the northwest. Grate Inlets ST4 and ST 3, part of the modifications, had picked up silt and debris during construction, which inspections showed was washing into biodetention basin 02A. The structures and piping from ST4 to ST 3 were cleaned during June 2020. Vegetation in all biodetention basins is managed as prescribed including cutting and removing for winter dormancy and managing unwanted growth periodically during the growing season. After carefully reviewing each component of the system and finding only routine maintenance needs to be addressed (see below), I can confirm: Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent. CUT AND REMOVE dead plant material before next spring (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- IN PROGRESS ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- NOT COMPLETED FILL in animal burrow and two sinkholes on embankments (Bayer) --- NOT COMPLETED REPLACE two broken standpipes at north end of the basin (Bayer) --- NOT COMPLETED FILL animal burrow at middle of west edge of basin (Bayer) --- NOT COMPLETED IMPROVE coverage of turf on northeast slope (Bayer) --- NOT COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED Post-Construction Stormwater BMP Inspection Report Field Observations: Diversion Structure in ST C2 Attribute Assessment Comments Green Green Pretreatment - Forebay (GIS-BMP-9634) Attribute Assessment Comments Green Green Green Green Green Green Green Green Green Green Green Green Green Biodetention Basin 01B (GIS-BMP-9634) Assessment Comments Green Green Green Green Green Green Yellow Green Green Green Yellow Green Yellow Green Green Assessment Comments Green Green Green Green Green Green Control Structure in ST F2 Assessment Comments Green Green Green Green Biodetention Basin 02A (GIS-BMP-8282) Assessment Comments Green Green Green Green Yellow Green Green Green Green Green Yellow Green Green Green Green Bayer EE Garage - December 6, 2023 Page 2 Water ponding on surface Small amount of ponding water in low spots Sheen on water surface None Clogging No indications of clogging Embankments Edges & embankments appear to be stable and remain vegetated Structural components Decorative rock lining has cracked plastic form at FES ST C12 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 1 Erosion Weeds Excessive foxtail growing on east embankment; weedy growth on surface is being treated Underdrain N/A Access Sediment Mulch No hardwood shredded mulch remaining on surface of basin Mulch N/A Attribute Turf Turf Plants Structural components Condition of filter media Water ponding on bottom Weeds Water ponding on surface Sheen on water surface Odor Sediment Perforated forebay outfalls were cleared of debris during the inspection No evidence of erosion on east embankment or anywhere else in forebay Up to 0.75" of sediment visible on river rock at low spots only Turf on embankments is in good condition ADD native plants to bare areas throughout biodetention basin (Bayer) IMPROVE coverage of turf on northeast slope, photo 2 (Bayer) Up to 0.125" of silt on surface at northeast perimeter from minor erosion of turf Turf on embankments is in good condition; some deterioration on northeast slope Nyloplast drain at ST F6 is clear of obstructions; underdrain end of pipe is not accessible Multiple probes confirm filter media is in good condition, photo 4 No ponding water Invasive growth was addressed during the 2023 growing season No ponding water Sufficient material in dry stream section below inlet covering fabric at scour None Underground StormTech Detention System (GIS-BMP-9637) Underdrain REPLACE two broken standpipes at north end of the basin, photo 3 (Bayer) Erosion No trash, debris or leaves noted Clogging Trash/debris/sediment Structural components Access Clear Trash/debris/leaves Trash/debris/leaves 1" of sediment in sump of ST F3 Sediment buildup in isolator row Approximately 67% of isolator row has 0.25 - 0.5" of sediment, photo 5 Sediment measured in isolator row Sediment measured at 1.25" below inspection port on 6/7/2023 inspection Attribute Access Manhole access at ST F3 and ST C1; ST C1 within 10 feet of beehives Attribute Access Trash/debris/leaves None Structural components Foundation stone appears to be level Attribute Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 6 Sediment buildup at low flow orifice None Structural components Clear, photo 23 Erosion No further scour at middle of north edge, but rock looks to have shifted, photo 8 Erosion Slight scouring of surface below ST E1 where water drains into basin Sediment No sediment visible on surface of basin Clogging No indications of clogging Water ponding on surface No ponding water Sheen on water surface FILL animal burrow at middle of west edge of basin (Bayer) Weeds Invasive growth was addressed during the 2023 growing season Underdrain ST D13 is clear of obstructions; no underdrain discharge is visible Structural components Sediment in rock blanket below ST E1 has stabilized since piping was cleaned Mulch Mulch is covering all embankments Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants ADD native plants to bare areas throughout biodetention basin, photos 6 & 7 (Bayer) Condition of filter media Multiple probes confirm filter media is in good condition Post-Construction Stormwater BMP Inspection Report Biodetention Basin O2B (GIS-BMP-8283) Assessment Comments Green Green Green Green Green Yellow Green Green Green Green Green Green Green Green Green Biodetention Basin 02C (GIS-BMP-9636) Assessment Comments Green Green Green Green Green Green Green Green Green Yellow Green Green Green Green Green Private Inlets/Manholes/Piping Assessment Comments Green Green Green Yellow Photographs See attached sheet(s) Inspector's Notes Bayer EE Garage - Bayer EE Garage - December 6, 2023 Page 3 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. March 8, 2023: Thick mulch was added around biodetention basins 02A - 02C. Basins were inspected during a light rain event. Native plants are starting to regrow. A lot of early spring season weeds were noted in biodetention basins 01B and 02A. The turf of the northeast embankment of biodetention basin 01B is deteriorating, likely from water existing the FES inlet above the sidewalk in the rip rap. Turf coverage on the embankment should be improved by adding compost to the embankment, reseeding with turf, and covering with seed germination blanket. June 7, 2023: Sediment has always been estimated as no more than 0.5 inches in the isolator row, looking up from the access manhole. Sediment was measured as 1.25" from the inspection port this visit. Invasive weeds should be removed periodically. Sediment is collecting in biodetention basin 02A below the inlet at ST E1. September 20, 2023: Invasive trumpet vine is spreading across the embankments and surface of biodetention basin O2B. December 6, 2023: Dead plant growth was removed. Standpipes are getting broken during the cut down and cleanup of vegetation during the winter. Standpipes need to be repaired to eliminate all openings below the level of the overflow structure. Munie representatives reached out to ask about planting plans and the recommended species. Adding native plants to bare spots is in progress. Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 11 Clogging No indications of clogging Attribute Erosion No further scouring noted around Nyloplast drain at ST D6 Sediment MONITOR for erosion under rock outlet Mulch Mulch is covering all embankments Water ponding on surface No ponding water Structural components Bottom of Nyloplast drain basin ST D6 is slightly cracked Animal burrow FILL two animal burrows along north end of basin, photo 12 (Bayer) Underdrain No underdrain discharge observed at ST D6 Structural components Nyloplast drain at ST D6 is clear of obstructions Condition of filter media Multiple probes confirm filter media is in good condition Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 11 Weeds Invasive growth was addressed during the 2023 growing season Underdrain Cleanout shows underdrain is dry and clear of obstructions Sediment Attribute Access Sediment - ST E4 to ST E3 Draining to Basin 02A Pipe was pressure washed and vacuumed to remove sediment Structural components No further sinkhole development at base of Nyloplast drain ST D8, photo 20 Condition of filter media Multiple probes confirm filter media is in good condition, photo 16 Erosion/settlement around structures System discharge REPAIR erosion at north edge of system discharge from ST F1, photo 24 (Bayer) MONITOR erosion on embankment to northwest of the rock outlet, photo 21 Mulch Mulch is covering all embankments Turf FILL in animal burrow and two sinkholes on embankments, photos 18 & 19 (Bayer) Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 15 Weeds Invasive growth was addressed during the 2023 growing season Sheen on water surface None Structural components Rock lining has crushed plastic FES form at ST G1, photo 22 Erosion Silt entering forebay from alongside pipe at STG1, photo 22 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 15 Clogging No indications of clogging Water ponding on surface No ponding water Attribute Access Decorative rock lining along building was repaired BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 1. VIEW OF BIODETENTION BASIN O1B (GIS- BMP-9634) 2. IMPROVE COVERAGE OF TURF ON NE EDGE OF BIODETENTION BASIN 01B 3. REPLACE TWO STANDPIPES AT NORTH END OF BIODETENTION BASIN 01B 4. FILTER MEDIA IS IN GOOD CONDITION – NO SEDIMENT PRESENT 5. VIEW OF ISOLATOR ROW WITH MINIMAL SEDIMENT (GIS-BMP-9637) 6. VIEW OF BIODETENTION BASIN 02A (GIS- BMP-8282) 7. ADD NATIVE PLANTS TO BARE AREAS OF BIODETENTION BASIN 02A 8. NO FURTHER SCOURING AT WALL OF BASIN 02A BUT ROCK HAS SHIFTED 9. SEDIMENT COLLECTING ON ROCK BLANKET OF BASIN 02A BELOW ST E1 10. MULCH IS COVERING ALL EMBANKMENTS 11. VIEW OF BIODETENTION BASIN 02B (GIS-BMP-8283) 12. FILL ANIMAL BURROWS AT NORTH END OF BASIN 02B BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 13. NO UNDERDRAIN DISCHARGE OBSERVED AT NYLOPLAST OVERFLOWS 14. DEAD PLANT MATERIAL WAS REMOVED FROM ALL BASINS 15. VIEW OF BIODETENTION BASIN 02C (GIS-BMP-9636) 16. SURFACE OF BIODETENTION BASIN 02C REMAINS VERY POROUS 17. SOIL HAS MORE SILT AND CLAY WHERE ERODING AT AT NW CORNER 18. FILL IN ANIMAL BURROW AT NORTHWEST CORNER IN BASIN 02C 19. FILL IN SINKHOLE ON SE EMBANKMENT OF BIODETENTION BASIN 02C 20. NO FURTHER SINKHOLE DEVELOPMENT AROUND ANY NYLOPLAST DRAINS 21. MONITOR EROSION ON EMBANKMENT TO NW OF THE ROCK OUTLET IN BASIN O2C 22. ROCK LINING HAS CRUSHED PLASTIC FES FORM AT INLET OF BASIN O2C 23. CONTROL STRUCTURE IN ST F2 SHOWS SYSTEM DISCHARGE TO BE CLEAR 24. REPAIR EROSION AT NORTH EDGE OF SYSTEM DISCHARGE FROM ST F1 Post-Construction Stormwater BMP Inspection and Maintenance Record Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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:January 18, 2019 Phone:(314) 229-8334 Record Start Date:June 21, 2018 E-mail:marianne@stormwater-stl.net Stormwater Treatment Facilities:Total Count: Count Type Description Count Type Description 4 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) 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) DET DETENTION WQS UNDERGROUND WATER QUALITY STORAGE 1 DET U UNDERGROUND 1 FBAY PRETREATMENT FOREBAY Inspection, Maintenance and Annual Report Submission Record: Date Activity Date Activity 2018.06.21 Initial 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 2020.03.05 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 2022.12.07 Inspection 2023.03.08 Inspection 2023.06.07 Inspection 2023.09.20 Inspection 2023.12.06 Inspection 6 Post-Construction Stormwater BMP Inspection Report Bayer Equip #:266288 MSD P Number:P001174323 Project:EE Garage - Parking 1 D 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 Inspector(s):Marianne Pott Bayer Company:Stormwater STL LLC Anna Tang Address:6514 Lansdowne Avenue 63109 314-694-3169 Phone:(314) 229-8334 anna.tang@bayer.com 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: ALL Biodetention Basins ALL Biodetention Basins Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 01B (GIS-BMP-9634) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin 02A (GIS-BMP-8282) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin O2B (GIS-BMP-8283) Biodetention Basin 02C (GIS-BMP-9636) Biodetention Basin 02C (GIS-BMP-9636) System Discharge Action Items Identified During This Inspection: No action items were identified during this inspection. Page 1 REPAIR erosion at north edge of system discharge from ST F1 (Bayer) --- NOT COMPLETED FILL two animal burrows along north end of basin (Bayer) --- NOT COMPLETED 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. CONTROL for growth of invasive weeds (Bayer) --- COMPLETED Construction for the Parking Garage was approved by MSD on January 18, 2019 and includes four biodetention basins, one forebay, and one underground StormTech detention system along with associated private inlets, manholes, and piping. Biodetention basins 02A - 02C were further modified by the Visitor Parking project to the northwest. Grate Inlets ST4 and ST 3, part of the modifications, had picked up silt and debris during construction, which inspections showed was washing into biodetention basin 02A. The structures and piping from ST4 to ST 3 were cleaned during June 2020. Vegetation in all biodetention basins is managed as prescribed including cutting and removing for winter dormancy and managing unwanted growth periodically during the growing season. After carefully reviewing each component of the system and finding only routine maintenance needs to be addressed (see below), I can confirm: Based on what was observed, this stormwater treatment system appears to be functioning in accordance with the design intent. CUT AND REMOVE dead plant material before next spring (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- IN PROGRESS ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD native plants to bare areas throughout biodetention basin (Bayer) --- NOT COMPLETED FILL in animal burrow and two sinkholes on embankments (Bayer) --- NOT COMPLETED REPLACE two broken standpipes at north end of the basin (Bayer) --- NOT COMPLETED FILL animal burrow at middle of west edge of basin (Bayer) --- NOT COMPLETED IMPROVE coverage of turf on northeast slope (Bayer) --- NOT COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED ADD thick covering of mulch to all embankments (Bayer) --- COMPLETED Post-Construction Stormwater BMP Inspection Report Field Observations: Diversion Structure in ST C2 Attribute Assessment Comments Green Green Pretreatment - Forebay (GIS-BMP-9634) Attribute Assessment Comments Green Green Green Green Green Green Green Green Green Green Green Green Green Biodetention Basin 01B (GIS-BMP-9634) Assessment Comments Green Green Green Green Green Green Yellow Green Green Green Yellow Green Yellow Green Green Assessment Comments Green Green Green Green Green Green Control Structure in ST F2 Assessment Comments Green Green Green Green Biodetention Basin 02A (GIS-BMP-8282) Assessment Comments Green Green Green Green Yellow Green Green Green Green Green Yellow Green Green Green Green Bayer EE Garage - December 6, 2023 Page 2 Water ponding on surface Small amount of ponding water in low spots Sheen on water surface None Clogging No indications of clogging Embankments Edges & embankments appear to be stable and remain vegetated Structural components Decorative rock lining has cracked plastic form at FES ST C12 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 1 Erosion Weeds Excessive foxtail growing on east embankment; weedy growth on surface is being treated Underdrain N/A Access Sediment Mulch No hardwood shredded mulch remaining on surface of basin Mulch N/A Attribute Turf Turf Plants Structural components Condition of filter media Water ponding on bottom Weeds Water ponding on surface Sheen on water surface Odor Sediment Perforated forebay outfalls were cleared of debris during the inspection No evidence of erosion on east embankment or anywhere else in forebay Up to 0.75" of sediment visible on river rock at low spots only Turf on embankments is in good condition ADD native plants to bare areas throughout biodetention basin (Bayer) IMPROVE coverage of turf on northeast slope, photo 2 (Bayer) Up to 0.125" of silt on surface at northeast perimeter from minor erosion of turf Turf on embankments is in good condition; some deterioration on northeast slope Nyloplast drain at ST F6 is clear of obstructions; underdrain end of pipe is not accessible Multiple probes confirm filter media is in good condition, photo 4 No ponding water Invasive growth was addressed during the 2023 growing season No ponding water Sufficient material in dry stream section below inlet covering fabric at scour None Underground StormTech Detention System (GIS-BMP-9637) Underdrain REPLACE two broken standpipes at north end of the basin, photo 3 (Bayer) Erosion No trash, debris or leaves noted Clogging Trash/debris/sediment Structural components Access Clear Trash/debris/leaves Trash/debris/leaves 1" of sediment in sump of ST F3 Sediment buildup in isolator row Approximately 67% of isolator row has 0.25 - 0.5" of sediment, photo 5 Sediment measured in isolator row Sediment measured at 1.25" below inspection port on 6/7/2023 inspection Attribute Access Manhole access at ST F3 and ST C1; ST C1 within 10 feet of beehives Attribute Access Trash/debris/leaves None Structural components Foundation stone appears to be level Attribute Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 6 Sediment buildup at low flow orifice None Structural components Clear, photo 23 Erosion No further scour at middle of north edge, but rock looks to have shifted, photo 8 Erosion Slight scouring of surface below ST E1 where water drains into basin Sediment No sediment visible on surface of basin Clogging No indications of clogging Water ponding on surface No ponding water Sheen on water surface FILL animal burrow at middle of west edge of basin (Bayer) Weeds Invasive growth was addressed during the 2023 growing season Underdrain ST D13 is clear of obstructions; no underdrain discharge is visible Structural components Sediment in rock blanket below ST E1 has stabilized since piping was cleaned Mulch Mulch is covering all embankments Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants ADD native plants to bare areas throughout biodetention basin, photos 6 & 7 (Bayer) Condition of filter media Multiple probes confirm filter media is in good condition Post-Construction Stormwater BMP Inspection Report Biodetention Basin O2B (GIS-BMP-8283) Assessment Comments Green Green Green Green Green Yellow Green Green Green Green Green Green Green Green Green Biodetention Basin 02C (GIS-BMP-9636) Assessment Comments Green Green Green Green Green Green Green Green Green Yellow Green Green Green Green Green Private Inlets/Manholes/Piping Assessment Comments Green Green Green Yellow Photographs See attached sheet(s) Inspector's Notes Bayer EE Garage - Bayer EE Garage - December 6, 2023 Page 3 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. March 8, 2023: Thick mulch was added around biodetention basins 02A - 02C. Basins were inspected during a light rain event. Native plants are starting to regrow. A lot of early spring season weeds were noted in biodetention basins 01B and 02A. The turf of the northeast embankment of biodetention basin 01B is deteriorating, likely from water existing the FES inlet above the sidewalk in the rip rap. Turf coverage on the embankment should be improved by adding compost to the embankment, reseeding with turf, and covering with seed germination blanket. June 7, 2023: Sediment has always been estimated as no more than 0.5 inches in the isolator row, looking up from the access manhole. Sediment was measured as 1.25" from the inspection port this visit. Invasive weeds should be removed periodically. Sediment is collecting in biodetention basin 02A below the inlet at ST E1. September 20, 2023: Invasive trumpet vine is spreading across the embankments and surface of biodetention basin O2B. December 6, 2023: Dead plant growth was removed. Standpipes are getting broken during the cut down and cleanup of vegetation during the winter. Standpipes need to be repaired to eliminate all openings below the level of the overflow structure. Munie representatives reached out to ask about planting plans and the recommended species. Adding native plants to bare spots is in progress. Access Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 11 Clogging No indications of clogging Attribute Erosion No further scouring noted around Nyloplast drain at ST D6 Sediment MONITOR for erosion under rock outlet Mulch Mulch is covering all embankments Water ponding on surface No ponding water Structural components Bottom of Nyloplast drain basin ST D6 is slightly cracked Animal burrow FILL two animal burrows along north end of basin, photo 12 (Bayer) Underdrain No underdrain discharge observed at ST D6 Structural components Nyloplast drain at ST D6 is clear of obstructions Condition of filter media Multiple probes confirm filter media is in good condition Turf No turf surrounding basin; embankments are covered with native vegetation and mulch Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 11 Weeds Invasive growth was addressed during the 2023 growing season Underdrain Cleanout shows underdrain is dry and clear of obstructions Sediment Attribute Access Sediment - ST E4 to ST E3 Draining to Basin 02A Pipe was pressure washed and vacuumed to remove sediment Structural components No further sinkhole development at base of Nyloplast drain ST D8, photo 20 Condition of filter media Multiple probes confirm filter media is in good condition, photo 16 Erosion/settlement around structures System discharge REPAIR erosion at north edge of system discharge from ST F1, photo 24 (Bayer) MONITOR erosion on embankment to northwest of the rock outlet, photo 21 Mulch Mulch is covering all embankments Turf FILL in animal burrow and two sinkholes on embankments, photos 18 & 19 (Bayer) Plants Excellent coverage of native vegetation; dead growth was cut down & removed, photo 15 Weeds Invasive growth was addressed during the 2023 growing season Sheen on water surface None Structural components Rock lining has crushed plastic FES form at ST G1, photo 22 Erosion Silt entering forebay from alongside pipe at STG1, photo 22 Trash/debris/leaves No trash, debris or leaves noted - basin was cleaned out for the winter, photo 15 Clogging No indications of clogging Water ponding on surface No ponding water Attribute Access Decorative rock lining along building was repaired BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 1. VIEW OF BIODETENTION BASIN O1B (GIS- BMP-9634) 2. IMPROVE COVERAGE OF TURF ON NE EDGE OF BIODETENTION BASIN 01B 3. REPLACE TWO STANDPIPES AT NORTH END OF BIODETENTION BASIN 01B 4. FILTER MEDIA IS IN GOOD CONDITION – NO SEDIMENT PRESENT 5. VIEW OF ISOLATOR ROW WITH MINIMAL SEDIMENT (GIS-BMP-9637) 6. VIEW OF BIODETENTION BASIN 02A (GIS- BMP-8282) 7. ADD NATIVE PLANTS TO BARE AREAS OF BIODETENTION BASIN 02A 8. NO FURTHER SCOURING AT WALL OF BASIN 02A BUT ROCK HAS SHIFTED 9. SEDIMENT COLLECTING ON ROCK BLANKET OF BASIN 02A BELOW ST E1 10. MULCH IS COVERING ALL EMBANKMENTS 11. VIEW OF BIODETENTION BASIN 02B (GIS-BMP-8283) 12. FILL ANIMAL BURROWS AT NORTH END OF BASIN 02B BAYER – EE Garage – Parking 1D Stormwater BMP Photos December 6, 2023 13. NO UNDERDRAIN DISCHARGE OBSERVED AT NYLOPLAST OVERFLOWS 14. DEAD PLANT MATERIAL WAS REMOVED FROM ALL BASINS 15. VIEW OF BIODETENTION BASIN 02C (GIS-BMP-9636) 16. SURFACE OF BIODETENTION BASIN 02C REMAINS VERY POROUS 17. SOIL HAS MORE SILT AND CLAY WHERE ERODING AT AT NW CORNER 18. FILL IN ANIMAL BURROW AT NORTHWEST CORNER IN BASIN 02C 19. FILL IN SINKHOLE ON SE EMBANKMENT OF BIODETENTION BASIN 02C 20. NO FURTHER SINKHOLE DEVELOPMENT AROUND ANY NYLOPLAST DRAINS 21. MONITOR EROSION ON EMBANKMENT TO NW OF THE ROCK OUTLET IN BASIN O2C 22. ROCK LINING HAS CRUSHED PLASTIC FES FORM AT INLET OF BASIN O2C 23. CONTROL STRUCTURE IN ST F2 SHOWS SYSTEM DISCHARGE TO BE CLEAR 24. REPAIR EROSION AT NORTH EDGE OF SYSTEM DISCHARGE FROM ST F1