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HomeMy WebLinkAboutBMP Inventory Memo - Year 6-May 2024 May 29, 2024 Marc Valenti Director of Operations Lexington Department of Public Works 201 Bedford Street Lexington, MA 02420 RE: MS4 General Permit Assistance for the Lexington Department of Public Works Year 6 Municipal Stormwater BMP Inspections and Inventory Dear Mr. Valenti, On April 13, 2016, the Environmental Protection Agency (EPA) released the General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems (MS4s) in Massachusetts, which became effective July 1, 2018. The Permit imposes a host of new requirements for the Town of Lexington and all communities under its jurisdiction. To address the Permit requirements (Section 2.3.7.a.iii.6) for the stormwater treatment structure inspections, Environmental Partners Group, LLC (EP) visited 170 of the Town’s 191 stormwater treatment best management practices (BMPs) to provide structure condition data and to improve the Town’s BMP inventory. EP did not visit any of the 21, private, non-school BMPs. During the time of inspections, two (2) additional stormwater BMPs were found and added to the Town’s BMP Inventory. As such, the new total count for stormwater BMPs is 172 for municipal jurisdiction, and 193 including the private, non-school BMPs. EP staff conducted site visits and inspections of the 172 BMPs in April 2024 and were performed during dry weather. Stormwater BMPs throughout the town and Charles River Watershed were inspected during this time. All BMPs visited are shown in Figure 1: Stormwater BMP Inspection Locations and listed in Table 1: Stormwater BMP Inventory, which also includes information about inventory notes and mapping updates recommended. Similar to last fiscal year, EP recommends removing four (4) BMP locations from the Town’s inventory due to private ownership, connection to sanitary sewer system, and non-existence and based on field observations and reviewed site plans. This fiscal year, EP added two (2) BMP to the Charles River Watershed inventory. Recommendations for further improving the Town’s BMP inventory and any changes made are further detailed in Table 1. Lastly, inspections were completed in PeopleGIS account using QA-Editor tools. Structure condition and maintenance issues were noted. Refer to the PeopleGIS inspection forms to view field visit Page 2 of 2 envpartners.com photos and notes. Inspection findings and maintenance recommendations are summarized in Table 2: Lexington Schools BMP Maintenance Items, Table 3: Non-School BMP Maintenance Items and Table 4: Charles River Watershed BMP Maintenance Items. In general, minor to moderate maintenance issues were observed, that include, but are not limited to: •Excess growth of vegetation, leaf litter buildup, and other dead vegetation, •Garbage and debris, •Buildup of sediment causing pooling at BMP inlets, •Rip rap needing sediment removal and/or stone material refreshed, •Areas requiring re-grading, •Inlets/outlets that were partially clogged with debris and/or sediment, and •Assets being inaccessible during the time of inspections either due to limited access or being buried under grass. We very much appreciate the opportunity to work with the Town of Lexington on this project. Please don’t hesitate to contact us if you have any questions or require additional information. Sincerely, Environmental Partners Group, LLC Natalie M. Pommersheim Project Manager and Associate O: 617.657.0257 E: nmp@envpartners.com CC John Zaccari – Lexington DPW Marissa Liggiero – Lexington Engineering Division Eric Kelley, P.E., CHMM, LEED GA – Environmental Partners Karen Chan – Environmental Partners Attachments MS4 Certification Page Figure 1: Stormwater BMP Inspection Locations Table 1: Town of Lexington Stormwater BMP Inventory Table 2: Lexington School BMP Maintenance Items Table 3: Lexington Non-school BMP Maintenance Items Table 4: Lexington Charles River Watershed BMP Maintenance Items envpartners.com MS4 CERTIFICATION PAGE CERTIFICATION “I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.” Printed Name ___________________________________________ Signature ________________________________________________ Date _________________________________________ envpartners.com FIGURE 1 Stormwater BMP Inspection Locations 0 1 20.5 Miles May 2024 Lexington, MA Stormwater BMP Inspection LocationsFigure 1 HANSCOM AFB 4 E l m B r oo k M ill St S o ut hRdWi gg i nsAveKendallRdWorth e n R d G rantStC edarSt Mi d d l e sex TpkeGre a t Rd RussellS tHartwellAve WoodSt GroveS t Wal tha mSt EastStHa n cockSt128 2 4 3 95 Hanscom Air Force Base Mary PC Cummings Park Hayden Woods Arlington Great Meadow Willard's Woods Burlington Strip EAST LEXINGTON IDYLWIDE NORTH LEXINGTON FULLER HEIGHTS COUNTRYSIDE FOLLEN HEIGHTS SHAKER GLEN LEXINGTON Hobbs B rook Bas in Trapelo Rd WinterStWymanStLake St L i n c o l nStOldCountyR dLexingtonStWalthamStHayden A v e 2 Beaver Brook North Reservation Belmont Country Club SUTHERLAND WOODS Lit tl es B rook Lex in g t o n StRev e re R d R u s s e llS t2A Whipple Hill A p p le to nSt ConcordTpkeParkAveStormwater BMPs Inspected Not Inspected (Private) Retired Charles River Watershed envpartners.com TABLE 1 Stormwater BMP Inventory Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes 3 Aaron Road MGT108 6 Aaron Road MGT109 12 Boxwood Lane MGT116 Infiltration Infiltration Trench See Table 3 Bridge Elementary School MGT124 Sediment Separator Contech No maintenance needed MGT123 Other Vegetated Filter Strip See Table 4 MGT175 Sediment Separator Contech No maintenance needed MGT121 Below-Grade Storage MGT122 Below-Grade Storage MGT144 Infiltration Subsurface Infiltration Unit No immediate maintenance needed MGT145 Infiltration Removed MGT145 was a duplicate point of MGT144 and has been retired PeoplesGIS. MGT146 Infiltration MGT147 Infiltration MGT148 Infiltration MGT149 Other Sediment Forebay MGT150 Other Sediment Forebay MGT162 Sediment Separator MGT163 Sediment Separator MGT164 Sediment Separator Hydroworks Hydroguard MGT165 Sediment Separator Hydroworks Hydroguard See Table 4 MGT166 Sediment Separator Hydroworks Hydrostorm MGT167 Sediment Separator Hydroworks Hydrostorm MGT168 Sediment Separator Hydroworks Hydrostorm MGT89 Unknown Bioretention Basin See Table 4 No immediate maintenance needed Bowman Elementary School Carey Memorial Library No immediate maintenance needed Dry Detention Clarke Middle School No immediate maintenance needed See Table 4 No immediate maintenance needed No immediate maintenance needed 1 of 7 Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes 13 Cider Mill Lane MGT209 Sediment Separator oil/grit separator Cider Mill Lane MGT107 Infiltration MGT154 Infiltration No immediate maintenance needed MGT156 Sediment Separator Hydroworks Hydroguard MGT157 Sediment Separator MGT158 Sediment Separator Hydroworks Hydroguard MGT159 Sediment Separator MGT160 Sediment Separator Hydroworks Hydroguard MGT161 Sediment Separator MGT48 Infiltration StormTech MGT80 Infiltration Bioretention Basin MGT81 Sediment MGT85 Other Drain outlet No immediate maintenance needed MGT86 Other Drain outlet MGT87 Unknown Bioretention Basin MGT88 Other Drain outlet MGT1 Below-Grade Storage Infiltration Chamber MGT100 Other Secondary ForebayMGT101OtherPrimary Forebay MGT102 Other Dome Field Inlet Recommend combining MGT13 with MGT102 as the two points are part of the MGT11 Filter Combine Recommend combining MGT11 with MGT96 as the two points are part of the MGT12 Filter Combine Recommend combining MGT12 with MGT98 as the two points are part of the MGT13 Filter Combine Recommend combining MGT13 with MGT102 as the two points are part of the MGT14 Dry Detention Wetland MGT15 Infiltration Porous Pavement MGT16 Infiltration Porous Pavement MGT17 Infiltration Porous Pavement MGT18 Infiltration Porous Pavement See Table 2 See Table 2 No immediate maintenance neededDPW See Table 3 See Table 3 Diamond Middle School See Table 3 2 of 7 Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes MGT19 Water Quality Swale MGT195 Sediment Separator Hydro International MGT194 was a duplicate BMP point and has been retired in PeoplesGIS.MGT2 Below-Grade Infiltration ChamberMGT3Below-Grade Infiltration ChamberMGT4Below-Grade Infiltration ChamberMGT5Below-Grade Infiltration ChamberMGT6Below-Grade Infiltration ChamberMGT7SedimentSedimentation ChamberMGT8FilterGreen Roof MGT9 Filter Combine Recommend combining MGT9 with MGT97 as the two points are part of the same BMP. MGT94 Water Quality Swale MGT95 Other Oil and Grease Trap Remove Part of sanitary sewer system. MGT96 Other Dome Field Inlet Combine Recommend combining MGT11 with MGT96 as the two points are part of the MGT97 Other Bioretention Basin Cleanout Combine Recommend combining MGT9 with MGT97 as the two points are part of the same BMP. No immediate maintenance needed MGT98 Other Dome Field Inlet Combine Recommend combining MGT12 with MGT98 as the two points are part of the MGT99 Other Stand Pipe 71 East Street MGT106 Infiltration No immediate maintenance needed See Table 3 DPW See Table 3 3 of 7 Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes MGT128 Sediment Separator Hydro International First Defense Unit No immediate maintenance needed MGT129 Dry Detention MGT130 Dry Detention MGT131 Sediment forebay MGT132 Other Sediment forebay MGT133 Dry Detention MGT134 Other Sediment Forebay No immediate maintenance needed MGT135 Dry Detention See Table 2 MGT136 Other Sediment Forebay MGT137 Dry Detention MGT191 Sediment Separator MGT193 Dry Detention MGT78 Remove BMP may not exist and is within the same BMP as MGT135. MGT79 Sediment Separator Overflow outfall should be mapped. MGT196 Other Porous Pavement MGT197 was a duplicate point of MGT196 and has been retired PeoplesGIS.MGT198 Other Sediment Forebay MGT199 Other Bioretention Basin MGT200 Other Sediment Forebay MGT201 Other Porous PavementMGT202OtherSediment ForebayMGT203OtherBioretention BasinMGT204OtherSediment Forebay MGT205 Other Bioretention Basin MGT206 Other Subsurface Infiltration MGT207 Other Subsurface Infiltration System See Table 3 Estabrook Elementary School See Table 2 Fire Department No immediate maintenance needed No immediate maintenance needed See Table 3 See Table 2 4 of 7 Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes MGT151 Infiltration Location updated MGT152 Infiltration MGT73 Infiltration 24" Perforated HDPE MGT74 Sediment Separator Vortech See Table 2 MGT75 Infiltration MGT76 Sediment Separator MGT77 Remove or combine This BMP should be removed / combined with MGT151.See Table 2 10 Fox Run Lane MGT103 Infiltration No immediate maintenance needed MGT61 Infiltration Moved MGT61 in PeoplesGIS to accurately reflect the BMPs correct locations. See Table 3 MGT62 Sediment Separator Moved MGT62 in PeoplesGIS to accurately reflect the BMPs correct locations. No maintenance needed MGT153 Infiltration See Table 2 MGT67 (retired) Infiltration (retired)Retired MGT68 Other MGT69 (retired) Other (retired)Retired MGT70 Infiltration Subsurface Infiltration Unit No maintenance needed MGT71 Infiltration MGT72 (retired) Infiltration (retired)Retired MGT182 Other Recharger No maintenance needed MGT184 Other Level Spreader MGT185 Other Level Spreader MGT186 Other Level Spreader MGT187 Other Stormwater Recharger No maintenance needed MGT188 Other Bioretention Basin MGT189 Other Bioretention Basin MGT190 Other Bioretention Basin MGT218 Other Porous Asphalt Added New BMP found and added during inspections. MGT219 Other Recharger Added Added during inspections, however, it appears that MGT183 is the actual BMP point for this unit, but in the wrong location. MGT220 Sediment Separator Contech Added New BMP found and added during inspections. MGT221 Sediment Separator Contech Added New BMP found and added during inspections. Fiske Elementary School 1 Granger Pond Way Harrington Elementary School Subsurface Infiltration Unit See Table 2; no immediate maintenance needed Subsurface Infiltration Unit See Table 2; no immediate maintenance needed No maintenance needed No immediate maintenance needed Hasting's Elementary School See Table 4 See Table 4 No maintenance needed 5 of 7 Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes MGT57 Other Settling Tank See Table 3 MGT58 Infiltration No immediate maintenance needed MGT59 Sediment Separator MGT60 Infiltration 5 Keller Farm Way MGT105 Infiltration MGT104 Infiltration MGT208 Sediment Separator Stormceptor 10 Keller Farm Way MGT211 Sediment Separator Stormceptor No immediate maintenance needed MGT125 Sediment Separator No maintenance needed MGT126 Sediment Separator MGT127 Below-Grade Storage MGT138 Other Porous Asphalt No immediate maintenance needed MGT139 Dry Detention MGT140 Infiltration MGT141 Dry Detention MGT142 Other Swale MGT143 Infiltration MGT169 Sediment Separator Contech MGT170 Sediment Separator Contech MGT171 Sediment Separator Contech No immediate maintenance needed MGT172 Sediment Separator Contech MGT173 Sediment Separator Contech MGT174 Sediment Separator No maintenance needed 5 Luongo Farm Lane MGT217 Sediment Separator Stormceptor Added BMP was added to inventory on 5/3/2023.See Table 3 7 Luongo Farm Lane MGT155 Other Subsurface Infiltration System 9 Luongo Farm Lane MGT210 Sediment Separator Stormceptor MGT51 Infiltration MGT52 Infiltration MGT53 Infiltration Munroe Center for the Arts MGT37 Dry Detention StormTech No immediate maintenance needed MGT118 Infiltration Bioinfiltration Basin MGT119 Infiltration Detention Pond MGT120 Filter Biofilter Basin Old Reservoir Parking lot MGT54 Filter Porous Asphalt Howard Munroe Place Johnson Farm Road See Table 3 3 Keller Farm Way Lexington High School See Table 2 Lexington Children's Place No immediate maintenance needed Minuteman Commuter Bikeway Parking Old Reservoir See Table 3 See Table 3 See Table 4 See Table 4 See Table 3 6 of 7 Town of Lexington Table 1: Stormwater BMP Inventory May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Inventory Notes Mapping/Other Notes Maintenance Notes MGT213 Infiltration MGT64 Sediment Separator Sedimentation Chamber 25 Robinson Road MGT39 Other Remove 33 Robinson Road MGT40 Other Remove 3 Smith Farm Lane MGT91 Infiltration No immediate maintenance needed 5 Smith Farm Lane MGT93 Infiltration No maintenance needed 5 Taylor Lane MGT63 Infiltration See Table 3 Tyler Road Intersection MGT117 Other Rock Swale No immediate maintenance needed MGT55 Other Settling Tank MGT56 Infiltration MGT20 Sediment Separator Sedimentation Chamber No immediate maintenance needed MGT21 Infiltration Infiltration Chamber See Table 3 MGT22 Sediment Separator Sedimentation Chamber MGT23 Infiltration Infiltration Chamber MGT212 Sediment Separator Sedimentation Chamber MGT92 Infiltration 6 Porter Lane See Table 3 See Table 3 9 Webb Street No immediate maintenance 3 Wisteria Lane 164 Wood Street See Table 3 No immediate maintenance needed 7 of 7 envpartners.com TABLE 2 Lexington Schools BMP Maintenance Items Town of Lexington Table 2: Lexington School BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description Bridge Elementary School MGT124 Sediment Separator Contech Contech unit - 4’ of standing water and 4" of sediment observed. Minimal floatables observed in contech structure. Inlet/outlet within contech structure is clear. Sediment does not exceed maintenance threshold. Unit in good condition. No immediate maintenance needed. MGT154 Infiltration Subsurface infiltration unit - The subsurface infiltration unit is functioning well. Clean out ports have minimal standing water and littler to no debris. Water level in outlet control structure is normal (below inlet pipe), indicating stormwater if flowing and infiltrating fine. No immediate maintenance needed. MGT156 Sediment Separator Hydroworks Hydroguard Hydrodynamic separator - Significant debris and sediment located at the inlet pipe. 6’ of standing water observed. Some floatables. Unit is overall in good condition. Routine maintenance such as cleaning is recommended. MGT157 Sediment Separator Hydroworks Hydroguard unit (likely HG4 model with 5’ sump) - 5’ of standing water measured. Little to no sediment observed at base of structure. Minimal amount of oil sheen. No floatables observed. Separator is overall functioning well and no immediate maintenance is required. MGT158 Sediment Separator Hydroworks Hydroguard Hydroworks Hydroguard unit (5’ sump, likely HG5 model) - A couple inches of sediment at base of structure, which is notable but less than threshold for maintenance. A few rocks and trash found in the structure and should be removed. Some floatable debris/trash but not exceeding threshold for maintenance. Outlet to basin is generally in good condition but riprap stones have some debris - debris should be cleared and stones reset. Inlet to separator from pavement contains some sediment that should be removed. Separator does not need maintenance but inlet and outlet need minor maintenance. MGT159 Sediment Separator Hydroworks Hydroguard unit - Inlet and outlet are in good condition. Sediment is observed at the flared end inlet pipe from the parking lot. Minor maintenance required. Water level in structure is below invert of outlet pipe. A couple inches of sediment observed which is notable but below the maintenance threshold. Minimal floatables Inlet to basin from separator is in good condition. Riprap contains only a minor amount of leaves. Aside from inlet from parking lot to separator, no immediate maintenance is needed. MGT160 Sediment Separator Hydroworks Hydroguard Hydroworks Hydroguard unit (HG5 model likely) - A few inches of sediment and some floatables observed, but lower than the 14" threshold, therefore, immediate maintenance is not required. Inlet from parking lot is clear. Outlet to basin is clear, but riprap contains some debris/leaves - minor maintenance needed. MGT161 Sediment Separator Hydroworks Hydroguard unit - Some sediment in structure, and observed to be below Hydroworks threshold for maintenance. 6' of standing water observed. Trash and leaves observed within structure. Inlet to structure requires cleaning of leaves and sediment. Outlet pipe to basin is in good condition, but riprap apron requires minor maintenance to clear riprap stones. Diamond Middle School 1 of 5 Town of Lexington Table 2: Lexington School BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT80 Infiltration Bioretention Basin Bioretention basin - Basin has layer of leaves and other dead vegetation which should be removed. Sedimentation is observed. Minor amount of trash observed. Inlet to structure has some sediment and should be cleared. No overflow outlet observed. MGT81 Sediment Separator Hydroworks Hydroguard unit - Trash and leaves observed. Inlet and outlet pipes within structure are in good condition. Sediment and leaves observed inside the flared end inlet pipe outside of the structure. Minor amount of trash found inside the unit. Maintenance such as cleaning for both the structure and inlet pipe outside of the structure is recommended. MGT85 Other Drain outlet Drain outlet - Inlet pipe is clear. Loose soil along slope of basin should be stabilized and reseeded as needed. Minor amount of leaves observed within riprap and should be cleared. Overall, basin is in good condition and no immediate maintenance is needed. MGT86 Other Drain outlet Drain outlet. Outlet is generally in good condition. Pipe is clear. Sedimentation is observed. Design drawings should be reviewed to confirm intended vegetation. Any excess vegetation should be removed and reseeded as designed. Reseed as needed. MGT87 Unknown Bioretention Basin Bioretention basin with under drain. Bottom of basin is soil - areas of soil need reseeding. Overall, basin has overgrowth and excess dead vegetation. Minor amount of trash noted. Outlet control structure has some leaf and debris buildup, but no immediate maintenance needed at the outlet. Routine maintenance such as removal of dead vegetation and reseeding the bottom of the basin (as needed) is recommended. MGT88 Other Drain outlet Drain outlet. Riprap at mouth of inlets have sediment and debris. Some leaves at mouth of one inlet. Minor amount of trash noted. Routine maintenance such as cleaing and removal of dead vegetation is recommended. Riprap should be refreshed/replenished as needed. Diamond Middle School 2 of 5 Town of Lexington Table 2: Lexington School BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT128 Sediment Separator Hydro International First Defense Unit Hydro International First Defense Unit (model FD4). Approximately 4" of sediment buildup. Minimal oils. Water depth is approximately 4'. Hydro recommends cleaning after 18” of sediment buildup. Clean in accordance with maintenance schedule. No immediate maintenance needed. MGT129 Dry Detention Sediment Forebay - minimal sediment and soil has built-up at start of forebay. Grass, leaves and minimal trash should be removed throughout forebay. Stone Filter Berm - overall in good condition, but leaves could be removed. Dry Detention Basin - confirm BMP type with landscape plan. Proposed plan calls structure “bioretention” but no plants aside from grass are growing. Minor amount of erosion observed on the slopes if the basin. Reseed as needed. Recharger - domed grate is in good condition. Subsurface chambers are dry with minimal sediment. No trash observed. Leaves observed in chamber beneath grate, but not enough to necessitate removal. No immediate maintenance required, however, leaves should be periodically removed. MGT130 Dry Detention Detention Basin - Floor of basin should be reseeded. No signs of erosion but signs of sedimentation. Overall, BMP is functioning well. Reseed as needed. No immediate maintenance needed. Spillway - stones contain leaves, dead branches and minor amounts of trash, which do not impede functioning, but could be removed for best practices. No immediate maintenance needed. Recharger - chambers have minimal sediment and leaves. No immediate maintenance needed. MGT131 Sediment forebay Sediment Forebay - Some sediment buildup observed. Refresh rip as needed. Sediment forebay grade should be restored to design conditions. No immediate maintenance needed. MGT132 Other Sediment forebay Stone filter berm / 3 connected swales - All inlets are full or partially full of stone, debris and leaves and requires routine maintenance. Stone berm contains sediment and leaf debris - stones should be cleared and refreshed. Some areas of sedimentation and loose soil on sides of swale and edge of pavement. Areas of soil in swale should have stones or grass/vegetation. Some weeds and dead vegetation noted. Routine maintenance such as removal of leaves and dead vegetation, and sediment recommended. Reseed basin as needed and as detailed in the site plans. Estabrook Elementary School 3 of 5 Town of Lexington Table 2: Lexington School BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT133 Dry Detention Dry Detention Basin - Reseed areas of the basin where grass is dead or absent. No trash, excess vegetation, etc. Overall in good condition. Routine maintenance such as clearing of dead and excess vegetation and trash is recommended. Recharger - overall in good condition. Minor leaves and dirt in chambers, but not enough to necessitate cleaning. No immediate maintenance needed. MGT134 Other Sediment Forebay Sediment forebay - Overall, sediment forebay is in good condition. Minor amounts of leaves and debris found within forebay. No immediate maintenance needed. MGT135 Dry Detention Dry Detention Basin - Areas of basin where grass has died or is absent need reseeding. Side of basin has evidence of erosion - reseed sides of basin without grass. Reseed basin and slopes of basin as needed and as recommended in the site plans. Recharger - chambers contain a moderate amount of trash and leaves. Routine maintenance such as clearing leaves and trash is recommended. MGT136 Other Sediment Forebay Sediment forebay - Overall, the sediment forebay has significantly improved compared to the last inspection. Minimal amount of leaves and debris found in forebay. No immediate maintenance needed. MGT137 Dry Detention Dry Detention Basin - Stones throughout basin contain some grass and sediment, but that should not impede BMP function. Minor amount of dead leaves and erosion observed. No immedate maintenance needed. Recharger - minimal sediment, trash, and leaves in chambers. Domed grates are in good condition. No immediate maintenance needed, however, leaves should be cleaned out regularly. Outlets : Leaf and rocks found within outlet. Outlet should be cleared to allow proper storm water flow. MGT191 Sediment Separator Hydro International separator located near asset DMH1666. First Defense model - No floatables, trash, or oil sheen. Approximately 7' of standing water and water is below the outlet pipe. A few inches of sediment in structure. No immediate maintenance needed. MGT193 Dry Detention Dry detention basin - Overall, basin is in good condition. Areas of dirt or dead grass should be reseeded. Riprap spillway overflow has some leaves which could be removed for best practices. No immediate maintenance needed. MGT78 -BMP does not exist and is within the same BMP as MGT135. Remove from PeoplesGIS and inventory. MGT79 Sediment Separator Sediment seperator - Minimal trash observed. Inlet pipe from playground is partially covered and needs some clearing. Outlet control structure need maintenance. Riprap area in front of control structure is full of leaves and large plants. Outfall near baseball field has trash and dead vegetation. Routine maintenance such as clearing larger, fallen trees, dead vegetation and removal of trash is recommended. Estabrook Elementary School 4 of 5 Town of Lexington Table 2: Lexington School BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT151 Infiltration Subsurface infiltration unit - Good condition. No sediment or debris. No immediate maintenance required. MGT152 Infiltration Subsurface infiltration unit. - Good condition. No sediment or debris. No immediate maintenance required. MGT73 Infiltration 24" Perforated HDPE Subsurface infiltration unit - Pre-treatment structure for this BMP was in good condition. No issues indicated. No immediate maintenance needed. MGT74 Sediment Separator Vortech Vortechnics Model 7000 separator unit - Approximately 3-ft of standing water observed. Approximately 7 inches of sediment build up. Maintenance guide suggests cleaning after 12-18 inches of sediment buildup. Routine maintenace such as cleaning is recommended after 12-18 inches of sediment is measured. Floatables chamber - significant amount of floatables. The chamber should be cleared of floatables. MGT75 Infiltration Subsurface chamber system - Opened observation well/port. Standing water observed. No immediate maintenance needed. MGT76 Sediment Separator Vortechnics Model 3000 sediment separator - Little to no debris or sediment. Little to no floatables noted. No immediate maintenance required. MGT153 Infiltration Could not locate BMP in parking lot or in surround grass within parking lot. No indication of BMP on site plans per Year 4 notes. MGT67 -MGT67 and MGT69 being duplicate points for MGT68, the BMP points have been retired. MGT68 Other Subsurface detention structure - There are 4 Nylonplastic observation ports located adjacent to structure. Structures are clean. A couple inches of standing water and debris observed in manhole structure. A few inches of sediment in the manhole. No immediate maintenance required. MGT69 -MGT67 and MGT69 being duplicate points for MGT68, the BMP points have been retired. MGT70 Infiltration Subsurface Infiltration Unit Subsurface infiltration unit - The inspection ports were opened and inspected. Small amount of standing water and sediment observed. No immediate maintenance required MGT71 Infiltration Subsurface Unit - Approx 2” of sediment buildup in BMP. No standing water observed. No immediate maintenance, aside from routine scheduled cleanings. MGT72 - MGT72 was a duplicate point for MGT71 and has since been retired. Town to review site plans and confirm connectivity of DMH2085. MGT125 Sediment Separator Sediment separator - Minor amount of sediment observed at inlet. Water level suggests stormwater is flowing as designed. Minimal sediment (<5”) and oil observed in base of structure. A couple of frogs found within the structure. No immediate maintenance needed. MGT126 Sediment Separator Stormceptor - Minimal oils. No large floatables. Estimated amount of sediment measured in the field is approximately 18" of sediment. Depth of standing water is 8'. The ports within the stormceptor is submerged under water. Cleaning of Stormceptor is recommended. MGT127 Below- Grade Storage Subsurface unit - Standing water and slight oil sheen observed in both the inspection port and the sub surface basin. Inspection port structures are semi sunken in. Regrading of pavement and routine cleaning is recommended. Subsurface Infiltration Unit Lexington High School Fiske Elementary School Harrington Elementary School Subsurface Infiltration Unit 5 of 5 envpartners.com TABLE 3 Non-School BMP Maintenance Items Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description 3 Aaron Road MGT108 Dry Detention Dry detention basin - Approximately 5' of standing water and some sediment observed. No immediate maintenance needed. Structure appears to be functioning properly. 6 Aaron Road MGT109 Dry Detention Dry detention basin - Approximately 5' of standing water and some sediment observed. No immediate maintenance needed. Structure appears to be functioning properly. 12 Boxwood Lane MGT116 Infiltration Infiltration Trench Sediment Forebay - Significant amount of sediment, leaf and vegetation buildup at inlet to structure. The forebay should be flat and inlet should be clear. Dirt and buildup should be removed so forebay is functioning properly. Routine maintenance such as cleaning is recommended. Infiltration Basin - Minor dead vegetation in outlet control structure and throughout the basin. Some erosion observed around the sides of the basin. Reseeding/restabilization of slopes recommended per site plans. No immediate maintenance needed. MGT121 Below- Grade Storage Subsurface infiltration gallery - No standing water observed. Sediment is observed. Routine maintenance such as cleaning is recommended. No immediate maintenance needed. MGT122 Below- Grade Storage Subsurface infiltration gallery - No standing water and oils or floatables observed. Moderate covering of sediment throughout galleries. Town to monitor sediment levels. No immediate maintenance needed. 13 Cider Mill Lane MGT209 Sediment Separator oil/grit separator Sediment separator (oil/grit separator) - Some sediment and approximately 30" of standing water observed. Some oil obseved. Outlet pipe in nearby infiltration basin is likely covered by leaves. Town should clean the sediment and trash from the chambers this year. Cider Mill Ln MGT107 Infiltration Infiltration Basin, located on a private road - The basin is overgrown and appears to not have been maintained in some time. The inlet pipe is partially full of leaves and dead vegetation. Additionally, the second inlet into the basin from the nearby separator was unable to be located and likely is covered by leaves. Full trees have grown up. Outlet structure appears to be functioning. Routine maintenance such as clearing of leaves in front of the inlets is recommended. Underdrain inspection ports were unable to be opened - Town should ensure underdrains are functioning properly. MGT1 Below- Grade Storage Infiltration Chamber Unable to open any inspection ports on this side of garage. Town to help open inspection ports to determine if structure is functioning. MGT100 Other Secondary Forebay Sediment forebay - Excess vegetation, phragmites, leaves, dead vegetation, sediment, and trash observed. Riprap areas are full of debris. Routine maintenance such as clearing of excess vegetation, trash and sediment is recommended. Riprap areas should be refreshed/cleaned as needed. Vegetation should be cut back in accordance with the planting plan. MGT101 Other Primary Forebay Sediment forebay - Sediment, plants, leaves, dead vegetation, dirt, grass, debris and trash observed. Phragmites (invasive species) noted. Routine maintenance such as clearing of debris, dead vegetation, trash and sediment is recommended. Riprap areas should be refreshed/cleaned as needed. Salt in front of the BMP should be regularly cleared/swept. MGT102 Other Dome Field Inlet Detention basin and dome field inlet - No cleaning needed of catch basin. Dead and excess vegetation observed. Routine maintenance such as clearing of dead and excess vegetation is recommended. The basin should primarily be grassed aside from a couple other plants - reference planting plans. Carey Memorial Library DPW 1 of 7 Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description MGT11 Filter Filter device to remove sediment from roof drainage - Sediment has accumulated and should be cleaned routinely. No immediate maintenance needed. Remove dead vegitation. MGT12 Filter Sediment and leaves observed in front of the inlet. Routine maintenance such as clearing of leaves and sediment is recommended. MGT13 Filter Inlet pipe is 5% full of sediment. Riprap is beneath the grass. Excess vegetation in front of the inlet pipe observed. Routine maintenance such as clearing of excess vegetation, removal of sediment and refreshing/replenishing riprap is recommended. MGT14 Dry Detention Wetland Wet basin - Trash, leaves, sediment, and other dead vegetation should be removed from basin. Basin water is very dark, suggesting lots of decaying vegetation and suspended solids. Phragmites (invasive species) observed, which should be removed. The riprap near the low point and entering the basin should be cleaned. Sedimentation is observed at the beginning of the basin at the rip rap. Rip rap should be refreshed/cleaned. MGT15 Infiltration Porous Pavement Pervious pavement - Some sediment noted. Parking area should be vacuum swept this Spring. MGT16 Infiltration Porous Pavement Pervious pavement - Some sediment noted. Parking area should be vacuum swept this Spring. MGT17 Infiltration Porous Pavement Pervious pavement - Some sediment noted. Debris has accumulated along curbing of parking area. Parking area should be vacuum and swept this Spring. MGT18 Infiltration Porous Pavement Pervious pavement. Some sediment noted. Parking area should be vacuum swept this Spring. MGT19 Water Quality Swale Water quality swale - The swale is significantly overgrown. Outlet is partially covered by vegetation. Riprap channels from parking lot are full of debris/soil. Algae is growing in water of swales, suggesting excess nutrients in swale. Routine maintenance such as clearing of excess vegetation, removal of sediment and trash, and refreshing/replenishing riprap is recommended. MGT195 Sediment Separator Hydro International Hydro International, Downstream Defender unit - Some sediment, approximately 3' standing water, vegitation, floatables, and oils observed. Full separator cleaning is recommended. Duplicate point of MGT194 and has been retired. MGT2 Below- Grade Storage Infiltration Chamber Subsurface infiltration unit - Filled with sediment. Full infiltration chamber cleaning is recommended. MGT3 Below- Grade Storage Infiltration Chamber Subsurface infiltration system - Unable to open 1 out of the 3 clean out ports. The port that was opened was full of debris. Town to assist with opening the stuck cleanout ports and clean the cleanout port filled with debris prior to the next inspection. MGT4 Below- Grade Storage Infiltration Chamber Subsurface infiltration unit - Unable to open inspection ports. Town to assist with opening the inspection ports prior to the next inspection and clean the ports as needed. MGT5 Below- Grade Storage Infiltration Chamber Subsurface infiltration unit - Only able to open 2 of the 4 cleanout ports. The 2 ports that were open were either full of sediment or had a broken clean out cover. Town to assist with opening the inspection ports prior to the next inspection and clean the ports as needed. MGT6 Below- Grade Storage Infiltration Chamber Subsurface infiltration unit - Unable to open inspection ports. Town to assist with opening the inspection ports prior to the next inspection and clean the ports as needed. DPW 2 of 7 Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description MGT7 Sediment Separator Sedimentatio n Chamber Hydro International Downstream Defender unit - Approximately 20" of sediment and some standing water and oils observed. Full separator cleaning is recommended. Follow Hydro International Downstream Defender unit manufacturer recommended cleaning instructions. MGT8 Filter Green Roof Rooftop garden/green roof - Overall, it's in good condition. Dead vegetation should be removed. Reference planting plan to ensure current vegetation is as designed and reseed as needed. MGT9 Filter Detention basin - Dead and excess vegetation observed. Both scupper inlets from parking area have leaf and sediment build- up. Minimal trash observed.Slope erosion is observed and the geotech mesh is exposed. Routine maintenance such as clearing of dead and excess vegetation, removal of sediment and trash is recommended. Beehive grate - covered with overgrown vegetation and standing water is observed. Routine maintenance such as removal of overgrown vegetation is recommended. MGT94 Water Quality Swale Two (2) water quality swales - Swales are overgrown. Dead vegetation, phragmites, sediment, and trash observed. Routine maintenance such as clearing of excess and dead vegetation, removal of sediment and trash is recommended. Swales should be generally cut back and routinely maintained. MGT95 Other Oil and Grease Trap Drains to sanitary sewer system; did not inspect. Suggest removing asset BMP inventory. MGT96 Other Dome Field Inlet Rain garden - Dead vegetation, leaves, overgrown vegetation and areas of dirt observed. Beehive grate is in good condition. Routine maintenance such as clearing of excess and dead vegetation, and reseeding areas of dirt is recommended. Reference planting plan to ensure plant growth is as designed. MGT97 Other Bioretention Basin Cleanout Beehive grate - Approximately 2' of standing water. A few inches of sediment has accumulated. Inlet/outlet are clear. No immediate maintenance needed. MGT98 Other Dome Field Inlet Dome field inlet - Standing water flush with the hood of the inlet pipe observed. Minimal sediment buildup. Dead vegetation, trash, and sediment observed. Routine maintenace such as clearing dead vegetation, trash and sediment is recommended. All dirt areas should be reseeded. The basin should primarily be covered with grass. MGT99 Other Stand Pipe Detention basin - Dead vegetation, leaves, weeds, trash, and sediment within riprap observed. Routine maintenace such as clearing dead vegetation, trash and sediment is recommended. All dirt areas should be reseeded. Both scupper inlets from parking area need to be cleaned of leaves and sediment - the riprap stones should be refreshed. 71 East Street MGT106 Infiltration Subsurface infiltration system - Some water and minimal sediment noted in system. Base of infiltration system seems to be stone. No immediate maintenance needed. DPW 3 of 7 Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description MGT196 Other Porous Pavement Porous Pavement - Sweeping should occur at least 2x annually with one event happening in May. Cleanout ports have little to no sediment. Overall, in good condition. MGT198 Other Sediment Forebay Sediment Forebay - Standing water, sediment, trash, dead vegetation and leaves observed. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. MGT199 Other Bioretention Basin Bioretention basin - Dead vegetation, leaves, trash observed. Minimal sediment and oil erosion observed around catch basin and throughout the basin. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. Reseeding and regrading of slopes are recommended per site plans. MGT200 Other Sediment Forebay Sediment Forebay - Significant sediment observed at the entrance of the forebay. Leaves, dead vegetation, and trash observed. Some erosion along the banks of the forebay observed. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. Riprap should be refreshed or replenished where needed. Reseeding and regrading of slopes are recommended per site plans. The small drainage channel from the pavement should be regraded to be a more gradual slope. MGT201 Other Porous Pavement Porous Pavement - Minimal sediment observed in cleanout ports. Sweeping should occur at least 2x annually with one event happening in May. MGT202 Other Sediment Forebay Sediment Forebay - Sediment, leaves, dead vegetation, and trash should be observed. The floor of forebay is clogged with leaves/etc. which limits infiltration. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. Riprap should be refreshed or replenished where needed. Stone channel from pavement needs to be cleared out - ensure grading is gradual. MGT203 Other Bioretention Basin Bioretention basin - Trash, dead vegetation, and leaves observed. Minor sediment build up and erosion observed. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. Ensure base of channel is vegetated. Reseeding as needed per site plans recommended. MGT204 Other Sediment Forebay Sediment Forebay - Trash, dead vegetation and some sediment observed. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. Stone channel into basin should be cleaned. MGT205 Other Bioretention Basin Bioretention basin - Dead vegetation, and leaves observed. Some erosion observed. Routine maintenace such as clearing dead vegetation, leaves, trash and sediment is recommended. Ensure base of channel is vegetated. Reseeding as needed per site plans recommended. MGT206 Other Subsurface Infiltration System Retain It Subsurface unit - Minimal sediment. Unit was dry. No issues noted. No immediate maintenance needed. MGT207 Other Subsurface Infiltration System Retain It unit - Some sediment observed at the bottom of the structure Manhole in front of bay 4 is minor amount of debris. No standing water observed at either of the manholes. Routine maintenance such as cleaning is recommended. Fire Department 4 of 7 Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description 10 Fox Run Lane MGT103 Infiltration Infiltration system - The manhole near residents garden appeared to be paved over. The next manhole, DMH1993, was opened an inspected. A couple inchs of sediment and 19" of standing water observed. Inlet from two (2) catch basins on East Street appear to discharge to this BMP - mapping updates needed. Town to assist with inspecting the asset and/or alert resident that BMP inspections will occur and that asset will need to accessible. No immediate maintenance needed aside from regularly scheduled cleanings. MGT61 Infiltration Infiltration system - No excess sediment or water observed in the inspection port. Outlet is filled with leaves. Removal of leaves and overgrown vegetation is recommended in front of the outlet. MGT62 Sediment Separator Sediment separator - Separator flows to infiltration system which flows to outfall. 3' of standing water and minimal sediment observed. No immediate maintenance needed. MGT57 Other Settling Tank Settling tank; The drain manhole at the edge of cul-de-sac garden (no asset ID). Approx. 12" standing water and 4" of sediment in sump observed. Routine maintenance such as cleaning is recommended. MGT58 Infiltration Infiltration system - Unable to locate any inspection port. Additional Town assistance needed to locate the inspection port. Outlet in downstream manhole - A ppears to be functioning normally. No signs of issues. No immediate maintenance needed aside from regularly scheduled cleanings. MGT59 Sediment Separator Sediment separator - A few inches of sediment and 13" of standing water. Some oils observed. Separator appears to be functioning; no immediate maintenance needed. Confirm connectivity; last years notes state that the structure does not go in the direction of the infiltration unit. While cleaning, Town should investigate BMP connectivity. MGT60 Infiltration Infiltration system - Could not locate infiltration system. The inlet pipe could be perforated and infiltrating but could not be confirmed during the time of inspetion. Site plans needed to confirm location of system. Outlet manhole (no asset ID) has some sedimentat the base of the manhole and no standing water. Routine maintenance such as cleaning is recommended for the outlet manhole. 5 Keller Farm Way MGT105 Infiltration Infiltration system - Could not locate infiltration observation port. Overall, the upstream and downstream structures appear to be working correctly. No immediate maintenance needed other than locating the inspection port .Town to assist in locating the observation port. MGT104 Infiltration Infilration system - Could not locate at time of inspection. Potentially buried under grass. Town to assist in locating the observation port. MGT208 Sediment Separator Stormceptor Stormceptor located in drain manhole (asset ID DMH2252) - Unable to open inspection port to fully inspect - cover was stuck. Some sediment observed in unit. Routine cleaning as mentioned in the O&M manual is recommended. 10 Keller Farm Way MGT211 Sediment Separator Stormceptor Stormceptor proprietary separator unit located in drain manhole (asset ID DMH2253) - 4" inches of sediment noted. No excess oils or trash. No immediate maintenance needed. 5 Luongo Farm Lane MGT217 Sediment Separator Stormceptor Stormceptor - Added in Year 5. Sediment and leaves found throughout the unit. Based on the amount of buildup found in the unit, it does not appear that the unit has been maintained in some time. Immediate cleaning of unit recommended to allow proper stormwater flow and treatment. 7 Luongo Farm Lane MGT155 Other Subsurface Infiltration System Infiltration subsurface system - Manholes upstream and downstream of subsurface infiltration unit opened and observed. Downstream manhole is DMH2396 and has some sediment - for best practices, the debris should be removed. Infiltration system does not reqiore immediate maintenance, but should be periodically cleaned, per manufacturer specifications. 9 Luongo Farm Lane MGT210 Sediment Separator Stormceptor Stormceptor - Approximately 4-8" of sediment. Oil sheen observed in inspection ports. Large clumps of debris observed. Inlet/outlet clear. No immediate maintenance needed aside from regularly scheduled cleanings. Howard Munroe Place 1 Granger Pond Way Johnson Farm Road 3 Keller Farm Way 5 of 7 Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description MGT51 Infiltration Infiltration system - Some sediment and trash. Structure appears to be outlet control structure of infiltration system - need site plans to confirm. Routine maintenance such as cleaning is recommended. MGT52 Infiltration Sedimentation chamber - Some sediment observed (approximately 10" measured). Standing water observed. Routine maintenance such as clearing of sediment build up is recommended. MGT53 Infiltration Infiltration system - During the time of inspection, the manhole could not be inspected and was seal shut. Town assistance required to open manhole. Per last year's notes, manhole likely needs cleaning. The downstream manhole is a sedimentation basin and was observe having approximately 10" of sediment. Munroe Center for the Arts MGT37 Dry Detention StormTech Filtration strip - The area is dry with minimal sediment and no trash. Vegetation immediately after filtration strip is dead, reseed as needed, per design plans. No oils or trash observed within catch basins or surroundingmanholes. No immediate maintenance needed. MGT118 Infiltration Bioinfiltration Basin Area has not been maintained in some time. All dead vegetation, fallen trees, sediment and trash should be removed. Confirm with design plans and town if the area is designed to be a constructed wetland. Stone Spillway - Leaves and encroaching vegetation observed. Remove leaves and sediment. All stones should be clear and visible. Basin - basin is overgrown with vegetation and contains dead vegetation. Basin is located in wetlands buffer; confirm with Town if maintenance can be conducted within and around the basin area. MGT119 Infiltration Detention Pond This pond is fully within wetlands delineation, according to site plans. It is likely that a BMP does not exist here. The pond located adjacent is the old reservoir. Verify with Town if this pond is a BMP (wet basin) MGT120 Filter Biofilter Basin Biofilter Basin - Dead vegetation, debris, and leaves observed. Reseeding may still be necessary as there are some patches of dirt on basin bottom and sides. Outlet control structure is generally in good condition; leaves observed in riprap, just below the outlet. Routine maintenance such as pruning, mowing, clearing of dead vegetation and leaves, and reseeding as needed is recommended. Sediment Forebay - Significant sedimentation at inlet. The base of the forebay should be a couple inches lower than invert of inlet, but instead it's higher. Riprap should be exposed and cleaned. Sedimentation seen in front and around the inlet structure should be removed. Old Reservoir Parking lot MGT54 Filter Porous Asphalt Porous pavement - It should be swept a minimum of 2x per year, once including once this Spring. Subsurface drains should be cleaned out at inspection ports with vacuum. Cleanout caps and cleanouts appear to be in good condition. MGT213 Infiltration Infiltration system - Resident was not home at the time of the inspection and could not be accessed. Per year 5's notes, the BMP has no outlet or access ports on site plan or identified in field. Upstream structure is the sedimentation basin, which likely requires cleaning. This structure likely needs cleaning as well, especially if it has not been maintained in a year or two. Per the site plans, the unit should be a 100 Cultec recharger 330 units. MGT64 Sediment Separator Sedimentatio n Chamber Sediment chamber - Resident was not home at the time of the inspection and could not be accessed. Manhole is buried under soil. Opend the upstream manhole dMH2041 and some sediment was observed. Per the year 5 notes, the BMP is a sedimentation basin. The basin likely needs maintenance/to be cleaned. Over 1' of sedment was observed last year. Town to monitor BMP and drainage area. Minuteman Commuter Bikeway Parking Lot Old Reservoir 6 Porter Lane 6 of 7 Town of Lexington Table 3: Non-school BMP Maintenance Items May 2024 Environmental Partners Location Facility ID BMP Category BMP Type Maintenance Description 25 Robinson Road MGT39 Other Opened upstream catch basin (IN7260) leading into the BMP and saw a 8" HDPE. Could not locate the specific BMP. Town to review BMP and determine if this site is worth retiring. 33 Robinson Road MGT40 Other Opened upstream catch basin (IN7261) leading into the BMP and saw a 8" HDPE. Could not locate the specific BMP. Town to review BMP and determine if this site is worth retiring. 3 Smith Farm Lane MGT91 Infiltration Infiltration system - Manhole (DMH2235) has weir and has some sediment with 17" standing water. Downstream manhole was in good condition. An oil sheen observed. No immediate maintenance needed. No manholes or cleanout ports on top of Subsurface unit found. 5 Smith Farm Lane MGT93 Infiltration Infiltration system - No trash, excess debris, no clogging. No immediate maintenance needed. 5 Taylor Lane MGT63 Infiltration Unable to locate any inspection port if it exists. The upstream manhole has some sediment and minor standing water. Routine cleaning is recommended. Since the infiltration system lacks pre-treatment to remove sediment, the Town could consider videoing the infiltration system, finding the inspection port, jetting the system, or another method to confirm that the system is working properly. Tyler Road Intersection MGT117 Other Rock Swale Rock swale - The swale better described as an infiltration trench or a sediment forebay. Reference site plan to confirm design intent. Stones have some sediment near pavement and minor dead vegetation. For best practices, Town could remove sediment and vegetation. No immediate maintenance needed. MGT55 Other Settling Tank Settling tank - Resident was not home during time of inspection, thus the downstream manhole DMH1997 was opened. Some sediment and standing water observed. The BMP likely consists of a deep sump manhole that collects sediment. No immediate maintenance needed aside from regularly scheduled cleanings. MGT56 Infiltration Unable to locate inspection port. It likely is locate in residential lawn or garden. Town should locate inspection port, if one exists. Outlet pipe in downstream manhole is clear. Minor amount of sediment observed in the downstream structure (asset ID DMH1996). No immediate maintenance needed aside from regularly scheduled cleanings. MGT20 Sediment Separator Sedimentatio n Chamber Sedimentation chamber - Deep sump catch basin. A couple inches of sediment. Oil sheen observed. No immediate maintenance needed. MGT21 Infiltration Infiltration Chamber Infiltration chamber - Could not locate at the time of inspection. Town assistance requested. MGT22 Sediment Separator Sedimentatio n Chamber Sedimentation chamber - Minimal amount of trash. No immediate maintenance needed. MGT23 Infiltration Infiltration Chamber Subsurface Infiltration System - Inspection port inspected and no sediment or water observed. No immediate maintenance needed aside from regularly scheduled cleanings. MGT212 Sediment Separator Sedimentatio n Chamber Sedimentation chamber - Downstream manhole (dMH2233) needs to be cleaned due to debris in inlets and outlets. The manhole was buried under grass and should be exposed. If the structure has not been cleaned in a couple of years, best practices suggest it should be cleaned. MGT92 Infiltration Infiltration basin - The upstream structure inlet could not be located. The sedimentation basin is a manhole, buried under grass. For best practices, the manhole should be exposed for easy access. Downstream manhole (dMH2233) needs to be cleaned due to debris in inlets and outlets. 3 Wisteria Lane 164 Wood Street 9 Webb Street 7 of 7 envpartners.com TABLE 4 Charles River Watershed BMP Maintenance Items Town of Lexington Table 4: Charles River Watershed BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT123 Other Vegetated Filter Strip Vegetated filter strip -There is some soil erosion around the filter strip. Reseed and replenish the filter in areas and where needed. Remove any overgrown and dead vegetation. MGT175 Sediment Separator Contech Contech unit - Approximately 4.5' of standing water and few inches of sediment observed. Minimal floatables. No immediate maintenance needed. Routine maintenance such as cleaning is recommended per the Contech O&M plan. MGT144 Infiltration Subsurface Infiltration Unit Subsurface infiltration unit - Minor sediment buildup. No standing water. Unit appears to be in good condition. No immediate maintenance needed. MGT146 Infiltration Subsurface infiltration unit - No water in unit. Some amount of trash and sediment in basin. Outlet control structure is in good condition. No immediate maintenance needed. Routine maintenance such as cleaning is recommended. MGT147 Infiltration Subsurface infiltration unit - Approx. 13” of standing water, with minimal sediment. Water level is 3" higher than that of the discharge wetlands. Verify if this manhole is actually an infiltration unit or a regular stormwater manhole. No immediate maintenance needed. MGT148 Infiltration Infiltration system - Approximately 5' of standing water and a few inches of sediment observed. No immediate maintenence needed. MGT149 Other Sediment Forebay Sediment forebay - Significantly overgrown. The riprap apron around the inlet is covered with plants, soil, and sediment. The inlet pipe has debris within it. The sides of the forebay also have excess vegetation and dead vegetation. Minimal trash noted. Routine maintenance such as pruning is recommended. Vegetation should be cut back to allow access to sediment forebay. MGT150 Other Sediment Forebay Sediment forebay - Significantly overgrown. Excess vegetation growth and dead vegetation noted. Some trash noted. Riprap areas have some soil, sediment, and vegetation. Gravel base also has soil and vegetation, especially near inlet. Dead vegetation noted on sides of structure. Inlet covered in debris. Routine maintenance such as pruning is recommended. Vegetation should be cut back to allow access to sediment forebay. MGT162 Sediment Separator Hydroworks Hydroguard unit - Approximately 5’ of standing water with a few inches of sediment. Inlet and outlet in good condition. Trash and organic floatables observed. No immediate maintenance required. Routine maintenance such as cleaning is recommended per the Hydroworks O&M manual. MGT163 Sediment Separator Contech unit - No floatables and minimal surface oils. Approximately 5' of standing water and some sediment observed. No immediate maintenance required. Routine maintenance such as cleaning is recommended per Contech O&M manual. Bowman Elementary School Clarke Middle School 1 of 5 Town of Lexington Table 4: Charles River Watershed BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT164 Sediment Separator Hydroworks Hydroguard Hydroworks Hydroguard unit - Standing water level is approximately 3’ lower than outlet invert, suggesting some infiltration is occurring in unit. Approximately 3" of sediment and minimal floatables observed. No immediate maintenance required. Routine maintenance such as cleaning is recommended per the Hydroworks O&M manual. MGT165 Sediment Separator Hydroworks Hydroguard Hydroworks Hydroguard unit - Approximately 3’ of standing water with 5" of sediment. Floatables consist of wood, leaves, and trash. Inlet is clear. Cleaning of sediment and floatables is recommended. Routine maintenance is also MGT166 Sediment Separator Hydroworks Hydrostorm Hydroworks Hydrostorm unit - Approximately 3' of standing water, a few inches of sediment and minimal floatables observed. No immediate maintenance required. Routine maintenance such as cleaning is recommended per the Hydroworks O&M manual. MGT167 Sediment Separator Hydroworks Hydrostorm Hydroworks Hydrostorm unit - Approximately 3' of standing water and afew inches of sediment at the bottom of the structure observed. Some trash on surface. No immediate maintenance needed but routine maintenance such as cleaning recommended per Hydroworks O&M manual. MGT168 Sediment Separator Hydroworks Hydrostorm Hydroworks Hydrostorm unit - Approximately 6' of standing water and few inches of sediment at the bottom of the structure observed. Some sediment buildup in front of the inlet structure but it does not appear to be hindering it's function. Minimal floatables. No immediate maintenance needed. Routine maintenance such as cleaning recommended per O&M plan. MGT89 Unknown Bioretention Basin Bioretention basin - Significantly overgrown but likely still functioning well. Inlet was buried during the time of inspection. Some trash noted. Dead vegetation observed on outlet pipe to wetlands. Outlet control structure is in good condition. No signs of erosion. Routine maintenance such as pruning recommended. Vegetation should be cut back and maintained. Clarke Middle School 2 of 5 Town of Lexington Table 4: Charles River Watershed BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT182 Other Recharger Contech unit - Approximately 5' of standing water and a few inches of sediment observed. Minor amount of floatables and trash in the standing water. No immediate maintenance needed. Routine maintenance such as cleaning is recommended per the Contech O&M manual. MGT184 Other Level Spreader Level Spreader - Heavy vegetation growth observed. Routine maintenance such as pruning is recommended. All vegetation and leaves should be removed from aggregate. MGT185 Other Level Spreader Level Spreader - Minor amount of debris and leaves observed. Routine maintenance such as clearing of debris and leaves is recommended. MGT186 Other Level Spreader Level spreader/vegetated filter strip - Some overgrown and dead vegetation observed throughout the area. Routine maintenance such as pruning is recommended. Remove excess and dead vegetation and replenish media where needed. MGT187 Other Stormwater Recharger Stormwater recharger - Classified as a stormwater recharger but it looks more like a subsurface infiltration unit. No standing water seen at the bottom of the structure. Replenish stones at the bottom of structure as needed. No immediate maintenance needed. MGT188 Other Bioretention Basin Bioretention basin - Leaves and debris within riprap observed. Routine maintenance such as clearing of leaves and debris within riprap recommended. Replenish/refresh riprap as needed. Contech unit - Approximately 3' of standing water and 10" of sediment ovserved. Some floatables and trash also observed. Routine maintenance such as cleaning is recommended per the Contech O&M manual. MGT189 Other Bioretention Basin Bioretention basin - Some trash excess vegetation and large amount of algae overgrowth observed. Routine maintenance such as pruning/mowing and refreshing of riprap is recommended. MGT190 Other Bioretention Basin Bioretention basin - Some overgrown vegetation throughout the bioretention area. Some trash observed at the mouth of the inlet. Routine maintenance such as pruning/mowing and removal of trash is recommended. Reseed as needed and as detailed in site plans. Hasting's Elementary School 3 of 5 Town of Lexington Table 4: Charles River Watershed BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT218 Other Porous Asphalt Porous asphalt - Routine sweeping recommended. No immediate maintenance needed. MGT219 Other Recharger Contech unit - Approximately 4" of sediment and 5' of standing water observed. Minor amount of trash found. Routine maintenance such as cleaning is recommended per Contech O&M plan. No immediate maintenance needed. Confirm with Town if MGT183 is a duplicate of new MGT219; if so, point can be removed. MGT220 Sediment Separator Contech Contech unit - Found during Year 6 inspections and added to inventory. The inlet and outlet are clear. Approximately 4' of standing water and 7" of sediment observed. Floatables and minor amount of trash. Routine maintenance such as cleaning is recommended per Contech O&M plan. No immediate maintenance needed. MGT221 Sediment Separator Contech Contech system - - Found during Year 6 inspections and added to inventory. Approximately 3' of standing water and a few inches of sediment observed. Routine maintenance such as cleaning is recommended per Contech O&M plan. No immediate maintenance needed. MGT138 Other Porous Asphalt Porous asphalt - Routine sweeping recommended. No immediate maintenance needed. MGT139 Dry Detention Detention basin - S ome overgrown vegetation seen throughout the basin. Routine maintenance such as pruning/mowing is recommended. Reseed as needed and as detailed in site plans. Sediment forebay - Remove overgrown and dead vegetation and trash where needed. Inlets - The inlets are clogged with leaves and sediment. Routine maintenance such clearing of inlets within the dry detention basin is recommended. MGT140 Infiltration Subsurface infiltration unit - Leaves and other debris seem to have washed in from upstream separator that needs immediate cleaning. Stone depth eroded at inlet discharge point. MGT141 Dry Detention Dry detention basin - Dead and overgrown vegetation observed . Little to no sediment buildup within riprap at the inlet structure. Routine maintenance such as clearing of dead and overgrown vegetation and refresh/replenished of riprap as needed is recommended. MGT142 Other Swale Swale - Significantly overgrown. Riprap near inlet still has sediment buildup allowing plants to grow. Dead vegetation throughout swale observed. Floor and sides of swale should be grassed. Minor amount of trash observed. Routine maintenance such as pruning/ mowing, removal of trash, and refreshing/replenishing of riprap is recommended. Reseed as needed and as detailed in site plans. Lexington Children's Place Hasting's Elementary School 4 of 5 Town of Lexington Table 4: Charles River Watershed BMP Maintenance Items May 2024 Environmental Partners School Name Facility ID BMP Category BMP Type Maintenance Description MGT143 Infiltration Could not locate the BMP during the time of inspection. Town assistance needed to locate. May be buried under grass. MGT169 Sediment Separator Contech Contech unit - Approximately 5.5' of standing water observed. Inlet is partially full of debris/sediment, and outlet has debris/sediment too. Flared-end inlet from pavement has sediment and leaf buildup . Routine maintenance such as sediment removal from inlet, outlet, and sump of unit is recommended. MGT170 Sediment Separator Contech Contech unit - Similar to last year, the separator is in poor condition. Significant sediment and leaf debris is observed within the unit. Inlet is clogged with sediment. Upstream inlet from the pavement has collected sediment and likely that sediment has overflowed into separator. Routine maintenance such as removal sediment and leaves from the inlet, and sump of unit is recommended. MGT171 Sediment Separator Contech Contech unit - A few inches of sediment at the bottom of the structure and a few inches of sediment at the inlet observed. Routine maintenance such as cleaning is recommended per Contech O&M plan. No immediate maintenance needed. MGT172 Sediment Separator Contech Contech unit - Buried under grass. Town to assist with accessing the structure. MGT173 Sediment Separator Contech Contech unit - Approximately 18" of standing water and 2" of sediment. Some floatables consisting of trash and debris. Sediment has accumulated near inlets, which is not currently impeding function. Routine maintenance such as cleaning is recommended and as needed per there Contech O&M manual. MGT174 Sediment Separator Sediment separator - No immediate maintenence needed. Lexington Children's Place 5 of 5