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HomeMy WebLinkAboutFOIL Packet GFR Field Turf 2025 03 31-pages-21 Paulette Rosa From:David Oshea <DOshea@townithacany.gov> Sent:Thursday, April 10, 2025 2:58 PM To:Paulette Rosa Subject:FW: SPDES Permit Review Question - Town of Ithaca David O'Shea, P.E. Director of Engineering/Town Engineer Town of Ithaca 607-273-1656 ext 257 From: Nicholson, Brian M (DEC) <Brian.Nicholson@dec.ny.gov> Sent: Monday, December 2, 2024 3:33 PM To: Justin McNeal <JMcNeal@townithacany.gov> Cc: David Oshea <DOshea@townithacany.gov>; Hanas, Debra (DEC) <Debra.Hanas@dec.ny.gov>; Emily Rodgers <erodgers@townithacany.gov> Subject: RE: SPDES Permit Review Question - Town of Ithaca Hi JusƟn, I reviewed a design manual from Aug. 2003 and I didn’t find the requirement to model ag land as meadow cover type back then, so I don’t want to hold them to that design standard from the design they developed in 2002/3. They can design the stormwater pracƟces based on the current site as exisƟng condiƟons and design the stormwater pracƟces accordingly to the new development. If your team has documentaƟon showing they were required to meet “Meadow cover” during the 2003 design, then we can look at holding them to that design standard. Thanks, Brian Brian M. Nicholson, P.E. Professional Engineer 1 (Env.) Region 7, Division of Water New York State Department of Environmental Conservation 5786 Widewaters Parkway, Syracuse, NY 13214-1867 P: 315-426-7530 | F: 315-426-7459 | brian.nicholson@dec.ny.gov www.dec.ny.gov | | From: Nicholson, Brian M (DEC) Sent: Wednesday, November 27, 2024 3:58 PM To: Justin McNeal <JMcNeal@townithacany.gov> Cc: David Oshea <DOshea@townithacany.gov>; Hanas, Debra (DEC) <Debra.Hanas@dec.ny.gov>; Emily Rodgers 2 <erodgers@townithacany.gov> Subject: RE: SPDES Permit Review Question - Town of Ithaca Hi JusƟn, I’ve sent out a couple of emails to see what my colleagues think about this situaƟon. I’ll get back to you next week with an answer. Thanks, Brian From: Justin McNeal <JMcNeal@townithacany.gov> Sent: Wednesday, November 27, 2024 8:07 AM To: Hanas, Debra (DEC) <Debra.Hanas@dec.ny.gov>; Nicholson, Brian M (DEC) <Brian.Nicholson@dec.ny.gov> Cc: David Oshea <DOshea@townithacany.gov>; Emily Rodgers <erodgers@townithacany.gov> Subject: SPDES Permit Review Question - Town of Ithaca ATTENTION: This email came from an external source. Do not open attachments or click on links from unknown senders or unexpected emails. Good Morning Deb and Brian, We would like some clarification regarding a proposed project in the Town of Ithaca. The project is proposing to convert an existing natural turf grass field with underdrains into a synthetic turf field along with a few small buildings, spectator facilities, and increasing the parking area at an existing sports complex. The existing site has a total of 4 natural turf grass fields with underdrains, a gravel parking lot and driveway, and a metal building with locker rooms and bathrooms. As part of the original project in 2003, 2 stormwater ponds were installed for both water quality treatment and quantity attenuation. The proposed project will be removing the 2 existing ponds and replacing them with an extended detention shallow wetland practice. At the time the SWPPP was approved in 2003, the applicant modeled the precondition as row crop. Only one of the natural grass turf fields will be disturbed during this project, the remaining 3 with remain undisturbed. Now that they are proposing to remove the 2 stormwater ponds with this project and install a new practice for attenuation, we are thinking the applicant should model the pre-condition as meadow prior to the 2003 project not the current pond outflows (which are based on the natural turf fields with under drains being considered a pervious surface). Our rational is based on recent guidance received from DEC pertaining to natural turf fields with underdrains being considered an impervious surface. How should this be handled? Should the applicant be required to re-evaluate the quantity attenuation for the entire site with the pre-construction condition being the condition prior to the 2003 project or can they use the pre- condition as the pond discharge rates which were developed based on the fields being considered as pervious? The question is ultimately being posed because a new attenuation practice is being installed to replace the ponds. Sincerely, Justin McNeal Civil Engineer Town of Ithaca Engineering Dept. 114 Seven Mile Drive Ithaca, NY 14850 Some people who received this message don't often get email from jmcneal@townithacany.gov. Learn why this is important 3 W: (607)-273-1656 Ext. 260 C: (607)-220-8342 1 Paulette Rosa From:David Oshea <DOshea@townithacany.gov> Sent:Thursday, April 10, 2025 2:58 PM To:Paulette Rosa Subject:FW: Game Farm Field Hockey Project Engineering Review Memo David O'Shea, P.E. Director of Engineering/Town Engineer Town of Ithaca 607-273-1656 ext 257 From: Justin McNeal <JMcNeal@townithacany.gov> Sent: Tuesday, December 10, 2024 10:47 AM To: Chris Balestra <CBalestra@townithacany.gov>; David Oshea <DOshea@townithacany.gov>; Emily Rodgers <erodgers@townithacany.gov> Cc: Abby Homer <ahomer@townithacany.gov> Subject: RE: Game Farm Field Hockey Project Engineering Review Memo Hello Chris, Yep, we would like to send them out to the applicant team so they can get a jump on the comments. We have had a couple of quick conversations with the Engineer, they have asked if we had reviewed the materials submitted and if we have any comments. We understand that they may need to change things as the Planning Board reviews materials, but we are also trying to coordinate reviews between the multiple Dev Rev projects. We would like to have this comment letter out to them before they send in the next set of revisions to limit the number of times we are reviewing the materials. Thank You, Justin McNeal Civil Engineer Town of Ithaca Engineering Dept. 114 Seven Mile Drive Ithaca, NY 14850 W: (607)-273-1656 Ext. 260 C: (607)-220-8342 From: Chris Balestra <CBalestra@townithacany.gov> Sent: Tuesday, December 10, 2024 10:30 AM To: Justin McNeal <JMcNeal@townithacany.gov>; David Oshea <DOshea@townithacany.gov>; Emily Rodgers <erodgers@townithacany.gov> Cc: Abby Homer <ahomer@townithacany.gov> Subject: RE: Game Farm Field Hockey Project Engineering Review Memo 2 Thanks Justin. This information is fantastic, but extremely premature. The PB hasn’t even decided to be the lead agency in the environmental review. And there’s a good chance that plans (and SWPPP) will need modification, as the project does go through the environmental review. We are about two steps away from that now. Are you sure you don’t want to hang onto these comments until a later phase of review (e.g., SEQR determination, or preliminary site plan review)? Christine Balestra, Senior Planner Town of Ithaca Planning Department 215 North Tioga Street Ithaca, NY 14850 (607) 273-1721, ext. 121 cbalestra@townithacany.gov From: Justin McNeal <JMcNeal@townithacany.gov> Sent: Friday, December 6, 2024 10:53 AM To: Chris Balestra <CBalestra@townithacany.gov> Cc: Abby Homer <ahomer@townithacany.gov> Subject: Game Farm Field Hockey Project Engineering Review Memo Good Morning Chris, We have completed our initial review of the Game Farm Field Hockey project. Could you please send this out to the project team? If you would like me to upload it somewhere specific instead, please let me know. Have a good weekend, Justin McNeal Civil Engineer Town of Ithaca Engineering Dept. 114 Seven Mile Drive Ithaca, NY 14850 W: (607)-273-1656 Ext. 260 C: (607)-220-8342 605 W. State Street | Ithaca, NY 14850 | phone 607-272-6477 | fax 607-273-6322 | www.tgmillerpc.com David A. Herrick, P.E. Frank L Santelli, P.E. Owen B. Barden, P.E. Donald M. Harner, P.E. LEED A.P., C.P.E.S.C. Lee Dresser, L.S. Jacqueline L. Dresser, L.S. March 14, 2025 Kimberly Van Leeuwen, RLA Director of Landscape Architecture Fisher Associates 1001 W. Seneca Street Ithaca, New York 14850 Re: Cornell University Game Farm Road Field Hockey Field Town of Ithaca SWPPP Review Comments Dear Ms. Van Leeuwen: Below please find our responses to review comments dated December 6, 2024 and prepared by David O’Shea, P.E. for the above referenced project. For ease of review, original review comments are re-stated and our responses are included in bold type. Sewer: 1.Prior to Final Site Plan Approval Submission, A Sewer Exemption Request must be submitted to the Town of Ithaca Engineering Department regarding the proposed septic system. The request will go before the Public Works Committee and the Town Board for review and approval. TGM Response: Acknowledged, a sewer exemption request was submitted to the Town by Cornell University on March 7, 2025. 2.All plan sheets should be updated to show the existing septic system filter area and proposed filter area. These areas should be delineated to be protected during construction. TGM Response: The existing septic system is noted on all project drawings and notes are added to protect these areas. Stormwater: 1.The complete SWPPP and associated documents will need to be uploaded to OpenGov under a SWPPP application and fee paid once they have been approved. TGM Response: The SWPPP will be uploaded to OpenGov and the application fee will be paid. 2.Revise the table of contents to correct page numbers and remove unused chapters. TGM Response: The table of contents has been revised accordingly. 3.Please update the SWPPP to include information and associated requirements for seeking a 5-ac waiver for disturbance. TGM Response: Page 1 of the SWPPP includes language regarding the need for written authorization prior to disturbing 5 acres. T.G. Miller, P.C. 2 4.Please indicate which version of the New York State Stormwater Management Design Manual was used for this project. TGM Response: The 2015 New York State Stormwater Management Desing Manual was used for the project. 5.Please update the Vol. I narrative regarding fill sites. If the fill site is within an MS4, the MS4 must approve the site and sign onto the SWPPP. TGM Response: Based on recent communications with NYSDEC Region 7 Staff, we have learned that remote fill sites (i.e. greater than ¼-mile from the project) do not need to sign onto the project SWPPP. It is still the responsibility of any fill site owner to comply with local and NYSDEC regulations pertaining to soil disturbance activities on the land of those fill sites. The written communications between TGM and NYSDEC will be shared with the Town Engineer. The SWPPP has been revised to reflect this. 6.Please update the SWPPP narrative to correctly and consistently identify the onsite soil groups. Dual soil groups are identified in the mapping. Please elaborate on what value you are using and why. TGM Response: The dual soil groups identified in the USDA soil survey have been added to on-site soil section of the SWPPP narrative. For areas where dual soil groups have been identified, they are assumed to have a HSG rating of “D”. This assumption is based on the onsite infiltration and percolation testing conducted (Please see response to comment #14 for additional information). Additionally, the previously approved 2003 SWPPP utilized a HSG rating of “D” for all dual soil group areas. 7.Please update existing tables or provide additional tables identifying the amount of new impervious per watershed. The map provided does not provide this information as you are modifying drainage boundaries. TGM Response: After further conversation with the Town Engineering staff this comment is no longer applicable. 8.Update the narrative to provide information on how the turf field will drain and get into the drainage system. TGM Response: The SWPPP narrative has been updated accordingly. 9.There are discrepancies between the SWPPP narrative and the site map regarding impervious and pervious acreage. Please provide clarification. If the main outer watershed boundary is not changing, Table 1 and Table 2 area summations should be equal. TGM Response: The SWPPP has been revised to address these discrepancies. 10.In Watershed 4, the narrative states the area is 11.73 acres of impervious surface, most of the area is pervious lawn. Please clarify this discrepancy. TGM Response: Existing watershed #4 has 0.86 acres of impervious cover, not 11.73. This has been revised in both the SWPPP narrative and on the existing watershed map. 11.The narrative references a Min Rv number of 0.2, but this value is not used in the water quality volume or runoff reduction calculations. Please revise the calculations accordingly. TGM Response: Calculations have been revised accordingly. T.G. Miller, P.C. 3 12.Please clarify why RRv is not being provided for impervious areas that are being disturbed. TGM Response: All existing impervious areas that will be disturbed are in Watersheds #4A and #5. The required RRv for each is 1,210 CF and 2,510 CF, respectively. Bioretention filter #1, located within watershed #4A, provides 1,716 CF of RRv while bioretention filter #2, located within watershed #5, provides 3,098 CF. It should be noted, there are sections of existing impervious area, a large portion of the gravel driveway, that is being restored to pervious lawn. 13.Please provide the borings logs as indicated in the SWPPP. They are not included. TGM Response: Boring logs have been attached to the SWPPP. 14.Please be more specific on why site limitations exist. Please include the definition and which criteria allows them to be utilized. TGM Response: Percolation testing was conducted at different locations throughout the site as part of the 2003 McGovern soccer field project geotechnical explorations. The results of these tests indicated infiltration rates of less than 0.5 in/hr. Additionally, the boring logs indicate a high prevalence of clay soils throughout the site. In support of the current project’s septic system design, T.G. Miller, P.C. conducted percolation testing. The results also indicated infiltration rates of less than 0.5 in/hr. Furthermore, the USDA soil survey report for the project indicates that the underlying soil for a large percentage of the project has hydrologic soils group rating of “D” or “C/D”. The geotechnical report has been attached to the SWPPP. 15.Sediment Traps and Sediment Basins are both called out in the narrative and plan set. Please verify which is being proposed. Please provide associated calculations and details as required by the New York State Standards and Specifications for Erosion and Sediment Control (Blue Book). TGM Response: All references to sediment traps have been removed. Sediment basin calculations and topography have been added to drawing C102. 16.Update the plan set to include a Concrete Washout Area and its associated construction detail. TGM Response: A concrete washout detail has been added to the drawings. 17.Please revise the plan set to include the following details: •Sediment Trap or Sediment Basin TGM Response: See response to comment #15. •Rock Check Dam TGM Response: A Rock Check Dam detail has been added. •Bioretention Filter Forebay and Weir. Please review this with the landscape plan relative to soils and vegetation requirements that differ between the forebay and the filter area. TGM Response: Bioretention filter and forebay plantings have been coordinated with landscape plans. •Extended Detention Short Wetland TGM Response: An enlarged plan of the extended detention ‘shallow’ T.G. Miller, P.C. 4 wetland has been added to the drawings. 18.Please add the following items to the plan set. •Include mound septic system on proposed drainage plan C105. TGM Response: The mound septic system has been added to C105. •Silt sock detail on Sheet C102 needs to be revised to match the Blue Book. TGM Response: The silt log detail on C102-3 has been revised. •Indicate material staging area on plan. Please note this area must be on a stabilized surface. TGM Response: The contractor material staging area has been added to all ESC plans. •Add winter stabilization procedures to the plan set. TGM Response: Winter stabilization notes have been to the ESC plans. •Indicate stream setbacks on all plan sheets. Please verify this setback was determined in accordance with the Code of the Town of Ithaca and accounts for any steep slopes that may be present. TGM Response: The stream setback has been added to all applicable plans where the viewport and scale allows. The stream setback shown was calculated in accordance with Town of Ithaca Code, inclusive of adjacent steep slopes. 19.Identify the length of the tracking pads. TGM Response: The length of the tracking pads has been added to the ESC plans. 20.Provide erosion and sediment control plan for phasing. TGM Response: Three erosion and sediment control plans have been prepared to reflect phasing. 21.Contour labels need to be added to the drainage plan in the stormwater practices where they are not provided on the grading plan. It would be beneficial for the contours in their entirety to be labeled on the drainage plan. TGM Response: Contour labels have been added within the extended detention shallow wetland. 22.There appears to be a difference between the drainage plan and grading plan. Please review and update accordingly. TGM Response: Drainage plan and grading plan have been coordinated. 23.The demo plan incorrectly identifies which pipe is being removed at the western pond. TGM Response: The demo plan has been revised accordingly. 24.Please review the existing catch basins and proposed grading plan. There are numerous basins around the proposed field that will need adjustments. Please review these basins and with other site improvements. There appears to be conflicts depicted in the plan set. TGM Response: Notes have been added to the drainage plan indicating rim elevation adjustments to all existing catch basins. All conflicts with site improvements have been resolved. 25.Please identify how the existing field drains (labeled tile outlet) will be handled. T.G. Miller, P.C. 5 TGM Response: Existing field drains will be daylighted into the proposed swale. A note has been added to drawing C105. 26.Update landscaping plans to identify native planting are required as mentioned in the SWPPP narrative. TGM Response: The landscaping plans have been revised accordingly. 27.The modeling of existing conditions must align with the post-conditions outlined in the 2003 SWPPP. This includes accurately representing the field conditions as pervious in the pre-condition per the 2003 SWPPP and now impervious for the post condition based on DEC’s current guidance. The ponds shall be modeled according to their post conditions in 2003 and incorporating any missing stormwater structures into the model. TGM Response: Below is a table summarizing the post-development peak discharge rates for both the 2003 McGovern SWPPP and the current CU GFR SWPPP. For the purposes of a pre- versus post-development comparison, the rates from 2003 SWPPP shall be considered as the pre-developed condition per the above Town review comment. As can be seen, the post-development peak discharge is attenuated for the 1, 10, and 100-yr storm events by the proposed stormwater management approach. The SWPPP narrative will be revised to consider the 2003 SWPPP post development runoff rates as the pre- development rates for the current project. Storm Event 2003 SWPPP (cfs)CU GFR SWPPP (cfs) 1-yr 12.43+21.82+7.54+7.56 = 49.35 0.67 10-yr 31.16+38.32+20+11.85 = 101.33 24.44 100-yr 33.9+41.9+24.51+11.26 = 111.57 75.79 28.Please provide additional information supporting your design that water will be conveyed to the attenuation device. Current modeling indicates that the structures are overtopping. TGM Response: Regarding diversion structure #1, runoff that may surcharge out of the structure will be captured by downstream drainage structures. If for any reason those structures become plugged and are not able to function, then all runoff will be conveyed to the attenuation device via the overland flow path between fields 3 & 4. Regarding diversion structure #2, the HydroCAD model has been revised so that runoff is no longer surcharging. 29.There are numerous discrepancies between the plan set and the HydroCad calculations. Please revise the materials accordingly. The calculations were not reviewed in detail due to the discrepancies. TGM Response: The HydroCAD calculations have been revised to be consistent with applicable device rims, inverts, and typical details.. 30.Please add the filters to the hydraulic modeling to verify how these systems are acting during the larger storm events (are they overtopping, do the overflow catch basins handle everything, etc.). TGM Response: Both bioretention filters have been added to the HydroCAD model. 31.Diversion Structure 2 appears to be overtopping into the bioretention filter. Provide T.G. Miller, P.C. 6 calculations for the wetland as described in Chapter 6 section 1 and 2 of the Stormwater Management Design Manual. Note stormwater wetlands must also meet the requirements of Stormwater Ponds. TGM Response: The HydroCAD calculations have been revised and diversion structure #2 no longer surcharges. Calculations have been added to Volume 1 of the SWPPP. Respectfully, David A. Herrick, P.E. Comment # = Plan Revision Required Comment # = Needs to be Completed Comment # = Completed Sewer: 1. Prior to Final Site Plan Approval Submission, A Sewer Exemption Request must be submitted to the Town of Ithaca Engineering Department regarding the proposed septic system. The request will go before the Public Works Committee and the Town Board for review and approval. TGM Response: Acknowledged, a sewer exemption request will be submitted prior to final site plan. 2. All plan sheets should be updated to show the existing septic system filter area and proposed filter area. These areas should be delineated to be protected during construction. TGM Response: The existing septic system will be noted on all project drawings and notes will be added to protect these areas. Stormwater: 1. The complete SWPPP and associated documents will need to be uploaded to OpenGov under a SWPPP application and fee paid once they have been approved. TGM Response: The SWPPP will be uploaded to OpenGov and the application fee will be paid. 2. Revise the table of contents to correct page numbers and remove unused chapters. TGM Response: The table of contents has been revised accordingly. 3. Please update the SWPPP to include information and associated requirements for seeking a 5-ac waiver for disturbance. TGM Response: Page 1 of the SWPPP includes language regarding the need for written authorization prior to disturbing 5 acres. 4. Please indicate which version of the New York State Stormwater Management Design Manual was used for this project. TGM Response: The 2015 New York State Stormwater Management Desing Manual was used for the project. 5. Please update the Vol. I narrative regarding fill sites. If the fill site is within an MS4, the MS4 must approve the site and sign onto the SWPPP. TGM Response: Based on recent communications with NYSDEC Region 7 Staff, we have learned that remote fill sites (i.e. greater than ¼-mile from the project) do not need to sign onto the project SWPPP. It is still the responsibility of any fill site owner to comply with local and NYSDEC regulations pertaining to soil disturbance activities on the land of those fill sites. The written communications between TGM and NYSDEC will be shared with the Town Engineer. 6. Please update the SWPPP narrative to correctly and consistently identify the onsite soil groups. Dual soil groups are identified in the mapping. Please elaborate on what value you are using and why. TGM Response: The dual soil groups identified in the USDA soil survey have been added to on-site soil section of the SWPPP narrative. For areas where dual soil groups have been identified, they are assumed to have a HSG rating of “D”. This assumption is based on the onsite infiltration and percolation testing conducted (Please see response to comment #14 for additional information). Additionally, the previously approved 2003 SWPPP utilized a HSG rating of “D” for all dual soil group areas. 7. Please update existing tables or provide additional tables identifying the amount of new impervious per watershed. The map provided does not provide this information as you are modifying drainage boundaries. TGM Response: The proposed watershed map will be updated to distinguish between existing and new imperious cover per watershed. 8. Update the narrative to provide information on how the turf field will drain and get into the drainage system. TGM Response: The SWPPP narrative has been updated accordingly. 9. There are discrepancies between the SWPPP narrative and the site map regarding impervious and pervious acreage. Please provide clarification. If the main outer watershed boundary is not changing, Table 1 and Table 2 area summations should be equal. TGM Response: The SWPPP has been revised to address these discrepancies. 10. In Watershed 4, the narrative states the area is 11.73 acres of impervious surface, most of the area is pervious lawn. Please clarify this discrepancy. TGM Response: Existing watershed #4 has 0.86 acres of impervious cover, not 11.73. This has been revised in both the SWPPP narrative and on the existing watershed map. 11. The narrative references a Min Rv number of 0.2, but this value is not used in the water quality volume or runoff reduction calculations. Please revise the calculations accordingly. TGM Response: For watershed #4A, a Min. RRv HSG reduction factor of 0.2 was used. This value is represented on the Water Quality Volume calculation sheet included in volume II. Please note, a value of 0.3 was used for watershed #5. 12. Please clarify why RRv is not being provided for impervious areas that are being disturbed. TGM Response: All existing impervious areas that will be disturbed are in Watersheds #4A and #5. The required RRv for each is 1,210 CF and 2,510 CF, respectively. Bioretention filter #1, located within watershed #4A, provides 1,716 CF of RRv while bioretention filter #2, located within watershed #5, provides 3,098 CF. It should be noted, there are sections of existing impervious area, a large portion of the gravel driveway, that is being restored to pervious lawn. 13. Please provide the borings logs as indicated in the SWPPP. They are not included. TGM Response: Boring logs have been attached to the SWPPP. 14. Please be more specific on why site limitations exist. Please include the definition and which criteria allows them to be utilized. TGM Response: Percolation testing was conducted at different locations throughout the site as part of the 2003 McGovern soccer field project geotechnical explorations. The results of these tests indicated infiltration rates of less than 0.5 in/hr. Additionally, the boring logs indicate a high prevalence of clay soils throughout the site. In support of the current project’s septic system design, T.G. Miller, P.C. conducted percolation testing. The results also indicated infiltration rates of less than 0.5 in/hr. Furthermore, the USDA soil survey report for the project indicates that the underlying soil for a large percentage of the project has hydrologic soils group rating of “D” or “C/D”. The geotechnical report and septic percolation testing have been attached to the SWPPP. 15. Sediment Traps and Sediment Basins are both called out in the narrative and plan set. Please verify which is being proposed. Please provide associated calculations and details as required by the New York State Standards and Specifications for Erosion and Sediment Control (Blue Book). TGM Response: All references to sediment traps have been removed. Sediment basin calculations and topography have been added to drawing C102. 16. Update the plan set to include a Concrete Washout Area and its associated construction detail. TGM Response: A concrete washout detail has been added to the drawings. 17. Please revise the plan set to include the following details: • Sediment Trap or Sediment Basin TGM Response: See response to comment #15. • Rock Check Dam TGM Response: A Rock Check Dam detail has been added. • Bioretention Filter Forebay and Weir. Please review this with the landscape plan relative to soils and vegetation requirements that differ between the forebay and the filter area. TGM Response: Bioretention filter and forebay to be coordinated with landscape plans. • Extended Detention Short Wetland TGM Response: An enlarged plan of the extended detention ‘shallow’ wetland has been added to the drawings. 18. Please add the following items to the plan set. • Include mound septic system on proposed drainage plan C105. TGM Response: The mound septic system has been added to C105. • Silt sock detail on Sheet C102 needs to be revised to match the Blue Book. TGM Response: The silt log detail on C102 has been revised. • Indicate material staging area on plan. Please note this area must be on a stabilized surface. TGM Response: The material staging area will be indicated on the plans. • Add winter stabilization procedures to the plan set. TGM Response: Winter stabilization notes will be added to the plans. • Indicate stream setbacks on all plan sheets. Please verify this setback was determined in accordance with the Code of the Town of Ithaca and accounts for any steep slopes that may be present. TGM Response: The stream setback has been added to all applicable plans where the viewport and scale allows. Yes, all shown stream setbacks shown are in accordance with Town of Ithaca standards. 19. Identify the length of the tracking pads. TGM Response: The length of the tracking pads has been added to drawing C102. 20. Provide erosion and sediment control plan for phasing. TGM Response: A phased erosion and sediment control plan will be added to the drawings. 21. Contour labels need to be added to the drainage plan in the stormwater practices where they are not provided on the grading plan. It would be beneficial for the contours in their entirety to be labeled on the drainage plan. TGM Response: Contour labels have been added to the extended detention shallow wetland. 22. There appears to be a difference between the drainage plan and grading plan. Please review and update accordingly. TGM Response: Drainage plan and grading plan will be coordinated. 23. The demo plan incorrectly identifies which pipe is being removed at the western pond. TGM Response: The demo plan has been revised accordingly. 24. Please review the existing catch basins and proposed grading plan. There are numerous basins around the proposed field that will need adjustments. Please review these basins and with other site improvements. There appears to be conflicts depicted in the plan set. TGM Response: Notes have been added to the drainage plan indicating rim elevation adjustments to all existing catch basins. All conflicts with site improvements have been resolved. 25. Please identify how the existing field drains (labeled tile outlet) will be handled. TGM Response: Existing field drains will be daylighted into the proposed swale. A note has been added to drawing C105. 26. Update landscaping plans to identify native planting are required as mentioned in the SWPPP narrative. TGM Response: The landscaping plans will be revised accordingly. 27. The modeling of existing conditions must align with the post-conditions outlined in the 2003 SWPPP. This includes accurately representing the field conditions as pervious in the pre-condition per the 2003 SWPPP and now impervious for the post condition based on DEC’s current guidance. The ponds shall be modeled according to their post conditions in 2003 and incorporating any missing stormwater structures into the model. TGM Response: Below is a table summarizing the post-development peak discharge rates for both the 2003 McGovern SWPPP and the current CU GFR SWPPP. For the purposes of a pre- versus post-development comparison, the rates from 2003 SWPPP shall be considered as the pre-developed condition per the above Town review comment. As can be seen, the post-development peak discharge is attenuated for the 1, 10, and 100-yr storm events by the proposed stormwater management approach. The SWPPP narrative will be revised to consider the 2003 SWPPP post development runoff rates as the pre- development rates for the current project. Storm Event 2003 SWPPP (cfs) CU GFR SWPPP (cfs) 1-yr 12.43+21.82+7.54+7.56 = 49.35 2.08 10-yr 31.16+38.32+20+11.85 = 101.33 30.68 100-yr 33.9+41.9+24.51+11.26 = 111.57 75.09 28. Please provide additional information supporting your design that water will be conveyed to the attenuation device. Current modeling indicates that the structures are overtopping. TGM Response: Regarding diversion structure #1, runoff that may surcharge out of the structure will be captured by downstream drainage structures. If for any reason those structures become plugged and are not able to function, then all runoff will be conveyed to the attenuation device via the overlayed flow path between fields 3 & 4. Regarding diversion structure #2, the HydroCAD model has been revised so that runoff is no longer surcharging. 29. There are numerous discrepancies between the plan set and the HydroCad calculations. Please revise the materials accordingly. The calculations were not reviewed in detail due to the discrepancies. TGM Response: The HydroCAD calculations have been revised to address these discrepancies. 30. Please add the filters to the hydraulic modeling to verify how these systems are acting during the larger storm events (are they overtopping, do the overflow catch basins handle everything, etc.). TGM Response: Both bioretention filters have been added to the HydroCAD model. 31. Diversion Structure 2 appears to be overtopping into the bioretention filter. Provide calculations for the wetland as described in Chapter 6 section 1 and 2 of the Stormwater Management Design Manual. Note stormwater wetlands must also meet the requirements of Stormwater Ponds. TGM Response: The HydroCAD calculations have been revised and diversion structure #2 no longer surcharges. Calculations have been added to volume 1 of the SWPPP.