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HomeMy WebLinkAboutSD-24-12 - Supplemental - 0500 Old Farm Road (8) Attachment 1: Narrative, Location Map, and Soils Map EASTVIEW 1. Introduction Krebs and Lansing Consulting Engineers Inc. (K&L) are writing on behalf of O’Brien Brothers to apply for a State Stormwater Discharge Permit pursuant to General Permit 3- 9050 for the next phase of the EASTVIEW project located on Kimball Avenue, O’Brien Farm Road, and Old Farm Road in South Burlington, Vermont. 2. Project Description The Eastview project is adjacent to the Hillside @ O’Brien Farm project. The project proposes a mix of single family, duplex, and tri-plex residential units, as well as future commercial and industrial development lots. The project proposes seven new roadways including Leo Lane, a relocation of a portion of Old Farm Road, an extension of O’Brien Farm Road, Daniel Drive, Barn Road, Mabel Way, and Potash Road. An additional alley, entitled Eastview Lane is also proposed. Shared driveways will serve new residences on Lots 24 and 36 for the project. The proposed stormwater treatment practices include seven new Gravel Wetlands. Forebays are provided for pre-treatment of non-rooftop runoff for each Gravel Wetland. Simple Disconnections will be used to treat rooftop runoff from the back of eight units along Mabel Way, and for the meandering gravel paths throughout the project. 2024 ADDENDUM There are three changes affecting the stormwater management system since the original application, described below: 1. Additional parking spaces have been added to the cottages on Lot 16. The buildings constructed to date on Lot 16 have been smaller that what was originally permitted, so that there is no net increase in impervious surface draining to Gravel Wetland #3 and SN004. Therefore, no changes to the worbooks, worksheets, or modeling were made for this discharge point. 2. Additional parking was also added to the cottages on Lot 36. This resulted in an increase of 0.07 acres of impervious surface draining to Gravel Wetland #4 and SN006. Because the increase was small relative to the overall watershed, all applicable standards are still met without needing to revise the treatment practice. The applicable workbook, worksheet, and modeling have been updated. 3. The parking lot for the barn on Lot 33 has been converted to regular pavement, rather than a pervious surface. This resulted in an increase of 0.20 acres of impervious surface draining to Gravel Wetland #5 and SN007. Because the increase was small relative to the overall watershed, all applicable standards are still met without needing to revise the Eastview Stormwater Narrative 2 treatment practice. The applicable workbook, worksheet, and modeling have been updated. 3. Existing Condition Phase 1 of the adjacent Hillside @ O’Brien Farm project is nearly built out, including most of the City Streets and single family and duplex units. The remaining portion of the site west of Old Farm Road is currently open meadow, or being used for construction staging and stockpiling. There is an existing house located at 205 Old Farm Road that will be demolished as part of the project. The west portion of the site is bordered by Kimball Avenue to the North, Old Farm Road to the east, and residential development to the west and south. This portion of the site slopes east to west away from Old Farm Road towards Kennedy Drive and Kimball Avenue. The portion of the project located east of Old Farm Road is mostly meadow, with some wooded areas and wetlands. The existing homes at 100 and 150 Old Farm Road will be demolished as part of the project. 200 Old Farm Road is not part of the project, and will remain. The Historic Barn between 150 and 200 Old Farm Road will also remain as part of the project. The east portion of the site is bordered by Kimball Avenue to the north, Potash Brook to the east, Old Farm Road to the west, and commercial lots in the Tilley Drive area to the south. This portion of the site generally slopes west to east, away from Old Farm Road, except for a crest where the existing houses and barn are located. Existing soil types on the site are a combination of Farmington Extremely Rocky Loam, Vergennes Clay, Covington Silty Clay, Enosburg & Whately soils, and Adams-Windsor loamy sands. Except for the Adams-Winsdsor soils, these soils are all mapped as type “D” soils, indicating a low infiltrative capacity and a high degree of runoff. Adams Windsor soils are classified as type A by the U.S. Soil Conservation Service, which normally indicates a low degree of runoff and high infiltrative capacity. However, on-site soil testing, as well as observation during construction, indicates a high seasonal groundwater table at less than three feet below existing ground surface throughout the site. This was verified through on- site testing wherever Adams Windsor soils are mapped on the site. See the Pre Development Watershed Map for soil test pit locations and logs. Due to the presence of high seasonal water table, these soils are also effectively type “D” soils. 4. Existing Stormwater System Stormwater Permit #7815-INDS was obtained in September 2017 for Phase 1 of the Hillside development. This permit also incorporated previously permitted infrastructure from Stormwater discharge Permit #1-1520. Existing permitted stormwater infrastructure includes Extended Detention Ponds 1, 2, and 3, Wet Ponds A and B, Infiltration Basin A, six grass channels, and four infiltration trenches. Wet Pond B and the infiltration trenches have not been constructed at this time. Wet Pond B will be converted to a Gravel Wetland #1 as part of a separate application for commercial development on Lots 10-15. Previously referenced, but not permitted, Wet Pond C, will be converted to Gravel Wetland #2 as part of the same application. Eastview Stormwater Narrative 3 There is no existing stormwater infrastructure on the east side of Old Farm Road. Old Farm Road itself either sheet flows to both sides, or flows to ditches that outlet to existing infrastructure on Hinesburg Road and Kimball Avenue respectively. 5. Proposed Stormwater System: The proposed stormwater collection, treatment, and detention system will utilize mostly enclosed drainage and seven new gravel wetlands. We have continued our numbering system for discharge points and gravel wetlands from the adjacent, related Hillside project. • The watershed draining to SN004 includes the portions of the project treated by Gravel Wetland #3. This area essentially includes Leo Lane and the houses, cottages, duplex, and triplexes fronting on Leo Lane. A portion of the existing Old Farm Road will also drain to this area. Because Gravel wetland #3 is not located adjacent to a potential discharge point, a large diameter pipe run has been designed to outlet the wetland to a discharge point under Kennedy Drive. • The watershed draining to SN006 includes the portions of the project treated by Gravel Wetland #4. This area includes Daniel Drive, Barn Road, a portion of Mabel Way and the houses, cottages, and duplexes fronting these roads. A portion of the existing Old Farm Road will also drain to this area. Gravel Wetland #4 outlets to an existing swale draining to the discharge point. The back rooftops of eight single family units will be disconnected and drain directly to the discharge point in this area. • The watershed draining to SN007 includes the portions of the project treated by Gravel Wetland #5. This area includes most of Mabel Way and Eastview Lane, along with the houses fronting these roads. A portion of the existing Old Farm Road and development around the Historic Barn will also drain to this area. Gravel Wetland #4 outlets near the discharge point in the Class 2 wetlands to the east. • The watershed draining to SN008 includes the portions of the project treated by Gravel Wetlands #6A and #6B. This area includes the relocated Old Farm Road, a portion of the houses along Eastview Lane, a portion of Mabel Way and the associated residences, along with the shared driveway and houses located on Lot 24. Both Gravel Wetland #6A and #6B are not located adjacent to potential discharge points. Therefore, large diameter pipe runs have been designed to outlet the gravel wetlands near the culvert under Kimball Avenue. • The watershed draining to SN009 includes the portions of the project treated by Gravel Wetland #7. This area includes northerly portion of Potash Road. Gravel Wetland #7 has been designed to accommodate future development on the adjacent industrial/commercial lots, but we are not permitting impervious area on the lots at this time. Gravel Wetland #7 outlets near the discharge point in the Class 2 wetlands to the east. • The watershed draining to SN010 includes the portions of the project treated by Gravel Wetland #8. This area includes southerly portion of Potash Road. Gravel Wetland #8 has been designed to accommodate future development on the adjacent industrial/commercial lots, but we are not permitting impervious area on the lots at this time. Gravel Wetland #8 outlets near an existing swale that will convey runoff to Potash Brook. Eastview Stormwater Narrative 4 All of the gravel wetlands feature forebay pre-treatment, and two interior cells. All outlets will be stabilized with rip-rap, and non-erosive. Conveyances from the project to the treatment practices are generally sheet flow or gutters/downspouts from roofs to enclosed drainage (catch basins and piping) in the roads. a) Description of Impervious Area: We offer the following summary of impervious areas by watershed: Discharge Point New Impervious (acres) 4 3.75 6 3.43 (previously 3.36) 7 4.18 (previously 3.98) 8 4.39 9 0.7 10 1.0 TOTAL 17.18 While there is “existing impervious” on the site from Old Farm Road and existing houses, we have treated this as “New” in order to offset portions of the project that are impossible to direct to treatment practices. These areas include the entrances to the relocated Old Farm Road and Potash Road, as well as the proposed recreation path along Kimball Avenue. A summary table of the site balancing areas are below: SUMMARY OF SITE BALANCING Untreated "New" Impervious Surface Existing impervious to remain treated to 100% standards Redeveloped impervious treated to 100% standards Description Area (ac) Description Area (ac) Description Area (ac) Relocated Old Farm Entrance 0.10 Old Farm Road 0.71 205 Old Farm Road 0.06 Kimball Ave Multi-Use Path 0.68 Barn buildings 0.08 Old Farm Road 0.20 Potash Road Entrance 0.08 Barn lot 0.07 Old Farm Road Sidewalk (New) 0.10 150 Old Farm Road 0.08 Old Farm Road Sidewalk (redeveloped) 0.02 100 Old Farm Road 0.02 TOTAL 0.98 TOTAL 0.79 TOTAL 0.43 Eastview Stormwater Narrative 5 The 0.98 acres of untreated “new” impervious is balanced by the (0.79 + ½ (0.43) = 1.0 acres of existing impervious surface being treated to 100% of the current standards. b) Receiving Body: i) S/N004: Wetlands in Potash Brook watershed ii) S/N006: Wetlands in Potash Brook watershed iii) S/N007: Wetlands in Potash Brook watershed iv) S/N008: Wetlands in Potash Brook watershed v) S/N009: Wetlands in Potash Brook watershed vi) S/N010: Potash Brook c) Fish Habitat Designation for Receiving Water: Warm d) Description of compliance with each of the treatment standards in the 2017 VSMM including the treatment practices or waivers used to meet each of the following standards: i) Post-Construction Soil Depth and Quality Standard: This standard will be met via two options outlined in the VSMM. Option 1: Areas outside of construction will be left undisturbed and protected from compaction during construction. This option will apply only to the far westerly portion of the site. Option 3: Remove and stockpile existing topsoil during construction. On site soil testing indicates and existing sandy loam topsoil layer on the site ranging from 7-13 inches in depth. Given that much of the finish site will be covered in building or paving, there will be an excess of existing topsoil to re store other disturbed areas such as setbacks, vegetated islands, swales, and side-slopes. Compost will be incorporated into the existing topsoil stockpile if needed to achieve 4% organic content. ii) Groundwater Recharge Standard: The Groundwater Recharge standard is waived because all of the developed areas are located in type “D” soils. iii) Water Quality Treatment Standard (WQV): (a) S/N004: WQv will be met for S/N 004 via the use of Gravel Wetland #3. The stone voids in the gravel wetland will store 50% of the WQv draining to the wetland. The remaining 50% WQv is provided by extended detention using small diameter orifices to release the remaining WQv over a 24 hour period. Pre-treatment is provided in a forebay. (b) S/N006: WQv will be met for S/N 006 via the use of Gravel Wetland #4. The stone voids in the gravel wetland will store 50% of the WQv draining to the wetland. The remaining 50% WQv is provided by extended detention using Eastview Stormwater Narrative 6 small diameter orifices to release the remaining WQv over a 24 hour period. Pre-treatment is provided in a forebay. (c) S/N007: WQv will be met for S/N 007 via the use of Gravel Wetland #5. The stone voids in the gravel wetland will store 50% of the WQv draining to the wetland. The remaining 50% WQv is provided by extended detention using small diameter orifices to release the remaining WQv over a 24 hour period. Pre-treatment is provided in a forebay. (d) S/N008: WQv will be met for S/N 008 via the use of Gravel Wetlands #6A and #6B. For each of the wetlands the stone voids in the gravel wetland will store 50% of the WQv draining to each wetland. The remaining 50% WQv is provided by extended detention using small diameter orifices to release the remaining WQv over a 24 hour period. Pre-treatment is provided in a forebay. (e) S/N009: WQv will be met for S/N 009 via the use of Gravel Wetlands #7. The stone voids in the gravel wetland will store 50% of the WQv draining to the wetland. The remaining 50% WQv is provided by extended detention using small diameter orifices to release the remaining WQv over a 24 hour period. Pre-treatment is provided in a forebay. (f) S/N010: WQv will be met for S/N 010 via the use of Gravel Wetlands #8 The stone voids in the gravel wetland will store 50% of the WQv draining to the wetland. The remaining 50% WQv is provided by extended detention using small diameter orifices to release the remaining WQv over a 24 hour period. Pre-treatment is provided in a forebay. iv) Channel Protection Standard (CPV): (a) S/N004: The Cpv standard is met by the use Gravel Wetland #3. The gravel wetland will feature an outlet structure using low flow orifices to provide the required detention time, or use the minimum orifice size required. (b) S/N006: The Cpv standard is met by the use Gravel Wetland #4. The gravel wetland will feature an outlet structure using low flow orifices to provide the required detention time, or use the minimum orifice size required. (c) S/N007: The Cpv standard is met by the use Gravel Wetland #5. The gravel wetland will feature an outlet structure using low flow orifices to provide the required detention time, or use the minimum orifice size required. (d) S/N008: The Cpv standard is met by the use Gravel Wetlands #6A and #6B. The gravel wetlands will feature outlet structures using low flow orifices to provide the required detention times, or use the minimum orifice size required. (e) S/N009: The Cpv standard is met by the use Gravel Wetland #7. The gravel wetland will feature an outlet structures using low flow orifices to provide the required detention time, or use the minimum orifice size required. (f) S/N0010: The Cpv standard is met by the use Gravel Wetland #8. The gravel wetland will feature an outlet structure using low flow orifices to provide the required detention time, or use the minimum orifice size required. Eastview Stormwater Narrative 7 v) Overbank Flood Protection Standard (QP10): (1) S/N004: The Overbank Flood Protection Standard is met by the use of Gravel Wetland #3. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 10 year, 24 hour storm event. (2) S/N006: The Overbank Flood Protection Standard is met by the use of Gravel Wetland #4. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 10 year, 24 hour storm event. (3) S/N007: The Overbank Flood Protection Standard is met by the use of Gravel Wetland #5. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 10 year, 24 hour storm event. (4) S/N008: The Overbank Flood Protection Standard is met by the use of Gravel Wetland #6A and #6B. The gravel wetlands use controlled outlet devices to limit post development peak flows to below pre development levels for the 10 year, 24 hour storm event. (5) S/N009: The Overbank Flood Protection Standard is met by the use of Gravel Wetland #7. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 10 year, 24 hour storm event. (6) S/N010: The Overbank Flood Protection Standard is met by the use of Gravel Wetland #8. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 10 year, 24 hour storm event. vi) Extreme Flood Protection Standard (QP100): (1) S/N004: The Extreme Flood Protection Standard is met by the use of Gravel Wetland #3. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 100 year, 24 hour storm event. (2) S/N006: The Extreme Flood Protection Standard is met by the use of Gravel Wetland #4. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 100 year, 24 hour storm event. (3) S/N007: The Extreme Flood Protection Standard is met by the use of Gravel Wetland #5. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 100 year, 24 hour storm event. (4) S/N008: The Extreme Flood Protection Standard is met by the use of Gravel Wetland #6A and #6B. The gravel wetlands use controlled outlet devices to limit Eastview Stormwater Narrative 8 post development peak flows to below pre development levels for the 100 year, 24 hour storm event. (5) S/N009: The Extreme Flood Protection Standard is met by the use of Gravel Wetland #7. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 100 year, 24 hour storm event. (6) S/N010: The Extreme Flood Protection Standard is met by the use of Gravel Wetland #8. The gravel wetland uses a controlled outlet device to limit post development peak flows to below pre development levels for the 100 year, 24 hour storm event. The following items are attached for review: • Attachment 1: Narrative: Narrative, Location Map, and Soils Map. • Attachment 2: Workbooks: STP Selection Tool and Standards Compliance Workbook • Attachment 3: Worksheets: STP and waiver worksheets, grouped by discharge point • Attachment 4: Modeling: Runoff modeling and calculations demonstrating compliance with the applicable treatment standards. Eastview Stormwater Narrative 9 Location Map [Insert project specific location map here. You may download topographic map from the Natural Resource Atlas. Please show the site outline, the location of the discharge point(s) and receiving waters. The scale of the location map should be between 1:20,000 and 1:40,000.] See Attached Location Map. Eastview Stormwater Narrative 10 Soils Map [Insert project specific soils map here. Soils information can be found at the Web Soil Survey website. Hydrologic Soil Groups— “HSGs” shall be overlaid with site outline. Soils information can also be provided as data layer on an existing or proposed condition plan sheet (if included as a data layer on one of the plan sheets please indicate that here] See Attached Soils Map. Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook The name above will appear on all the discharge point tabs Site Summary Total SN1 SN2 SN3 SN4 SN5 SN6 SN7 SN8 SN9 New 16.18 0.00 0.00 0.00 3.75 0.00 3.36 3.98 4.39 0.70 Redeveloped 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Existing 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Previously  Authorized 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Total 16.18 0.00 0.00 0.00 3.75 0.00 3.36 3.98 4.39 0.70 Site Area 46.46 0.00 0.00 0.00 6.55 0.00 11.10 15.52 9.20 4.09 0.00000 0.00000 0.00000 44.46044 0.00000 44.45444 44.45584 44.45650 44.45452 0.00000 0.00000 0.00000 ‐73.16017 0.00000 ‐73.15299 ‐73.15221 ‐73.15097 ‐73.14914 Receiving Water Potash  Brook Wetlands  in Potash  Brook  Watershed Wetlands  in Potash  Brook  Watershed Wetlands  in Potash  Brook  Watershed Wetlands  in Potash  Brook  Watershed Recharge Total SN1 SN2 SN3 SN4 SN5 SN6 SN7 SN8 SN9 Required 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Provided 0.0283 0.0000 0.0000 0.0000 0.0000 0.0000 0.0283 0.0000 0.0000 0.0000 Standard met?Yes n/a n/a n/a n/a n/a n/a n/a n/a n/a Notes: Water Quality Total SN1 SN2 SN3 SN4 SN5 SN6 SN7 SN8 SN9 Required 1.4071 0.0000 0.0000 0.0000 0.3085 0.0000 0.2983 0.3632 0.3676 0.0695 Provided 1.4071 0.0000 0.0000 0.0000 0.3085 0.0000 0.2983 0.3632 0.3676 0.0695 Standard met?Yes n/a n/a n/a Yes n/a Yes Yes Yes Yes Notes: Channel Protection A minimum WQ V of 0.2" (P*R V ) is required for sites with low impervious (<16.67%).  This calculation has not been incorporated  into this workbook. Designers should check that the minimum WQ V  has been met for their site. Im p e r v i o u s Project Name Do not fill this tab out, apart from the project name and notes.  It will auto‐populated based on the values on the discharge point  tabs. Discharge points (SN) will only show on the summary if an area has been entered on that tab. Areas listed below are those  seeking permit coverage. EASTVIEW Latitude Longitude Last Updated 8/28/2018 Summary: Page 3 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Total SN1 SN2 SN3 SN4 SN5 SN6 SN7 SN8 SN9 Standard Applies?000Yes 0 Yes Yes Yes Yes Waiver n/a n/a n/a n/a n/a Method n/a n/a n/a Extended  Detention n/a Extended  Detention Extended  Detention Extended  Detention Extended  Detention HCV 1.8933 0.0000 0.0000 0.0000 0.3950 0.0000 0.3937 0.4886 0.5111 0.1049 TV Provided 0.0283 0.0000 0.0000 0.0000 0.0000 0.0000 0.0283 0.0000 0.0000 0.0000 Notes: Overbank Flood Protection SN1 SN2 SN3 SN4 SN5 SN6 SN7 SN8 SN9 Standard Applies?000Yes 0 Yes Yes Yes Yes Pre‐Dev Q (cfs) 9.63 20.51 23.99 15.72 8.09 Routed, Post‐Dev Q (cfs) 7.04 15 13.45 11.5 0.73 Waiver n/a n/a n/a n/a n/a Notes: Extreme Flood Protection SN1 SN2 SN3 SN4 SN5 SN6 SN7 SN8 SN9 Standard Applies?Yes Yes Yes Yes Yes Pre‐Dev Q (cfs) 19.35 40.72 48.07 31.87 16.28 Routed, Post‐Dev Q (cfs) 19.2 36.77 45.19 22.05 1.24 Waiver n/a n/a n/a n/a n/a Notes: General Notes Last Updated 8/28/2018 Summary: Page 4 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Last Updated 8/28/2018 Summary: Page 5 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook General Discharge Point Information Project name Discharge point serial number (e.g. S/N 001) Name of receiving water  Latitude (decimal degrees to five decimal places) Longitude  (decimal degrees to five decimal places) Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Total Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 6.270 6.270 Existing Impervious 0.000 0.000 0.000 0.280 0.280 Impervious previously authorized under 2002 VSMM (not included in calculations)0.000 Total Pre Site Area 6.550 %  Landuse A B C D Total Grass 0.000 0.000 0.000 2.800 2.800 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 New Impervious 0.000 0.000 0.000 3.750 3.750 57.3% Existing for Permit  Coverage (Treated to New  Standards) 0.000 0.000 0.000 0.000 0.000 0.0% Existing Impervious Not for Permit Coverage 0.000 0.0% Redeveloped Impervious 0.000 0.0% 0.000 Total Site Area 6.550 Total Impervious for Permit Coverage 3.750 Net Reduced Impervious 0.000 0.0% Reduced Existing Impervious (for redevelopment)0.280 100.0% Average  Catchment  Slope, Y (%) Hydraulic  Length, l (ft) Pre Development 6.12 1500.00 Post Development 6.12 1500.00 EASTVIEW S/N 004 Potash Brook 44.46044 ‐73.16017 * Preciptation values shall be obtained from  Pre Development Land Use (acres) Post Development Land Use (acres) Impervious previously authorized under 2002 VSMM Information for Calculating TC by the  Watershed Lag Method  Last Updated 8/28/2018 SN4: Page 6 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Runoff Calculations 1 yr, 24‐hr 10 yr, 24‐hr 100 yr, 24‐hr 0.2458 0.7223 1.4129 0.6408 1.2790 2.0863 Tier 1/Runoff Reduction Practices Practice TV (ac‐ft) TV (ac‐ft) Runoff Reduction Calculations Standard Re WQ CP QP10 QP100 TV Required (ac‐ft)0.0000 0.3085 0.3950 0.5567 0.6734 TV Provided (ac‐ft)0.0000 0.0000 0.0000 0.0000 0.0000 TV Remaining (ac‐ft)0.0000 0.3085 0.3950 0.5567 0.6734 Standard met with HCM?n/a No No No No Post‐Development CN n/a 95 92 91 91 CNadj n/a 95 92 91 91 Pre‐Development CN n/a n/a 79 78 78 Groundwater Recharge Standard (Re)2 Standard Applicable? ReV 0.0000 Standard met with Tier 1  Practices? n/a  Recharge Notes: HSG D Soils Predevelopment runoff volume (ac‐ft) Pre‐routed, post development runoff volume (ac‐ft) List all Tier 1 practices below with the associated treatment volume (TV ).  The T V  will be applied to all treatment standards,  except for Green Roofs, which do not receive recharge or water quality credit. Please include the appropriate STP  worksheet(s) with the application. Practice Reason recharge not required  (if No is selected):Yes No Last Updated 8/28/2018 SN4: Page 7 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Water Quality Treatment Standard (WQ)11 (ac‐ft) Apply Reduction? WQV ‐ New & Existing 0.3085 0.0% WQV ‐ Redevelopment 0.0000 100.0% Max 25%  applied Total WQV 0.3085 WQV met with Tier 1  practices 0.0000 1 WQV to be met with Tier 2  and/or Tier 3 practices 0.3085 WQV Provided  (ac‐ft)Tier 0.3085 Tier 3 Total WQV Provided (ac‐ft)0.3085 ac‐ft Is the WQV Standard met?Yes Water Quality Notes: Channel Protection Standard (CP)21 Standard Applicable? Standard Met with HCM?No Provide Extended  Detention for:0.641 ac‐ft Warm or Cold Water  Fishery?→Provide: FALSE Extended Detention STP: CNAdj 92 11.3 (Watershed  Lag Method) Channel Protection Notes: % Net Reduction % Removed Existing  Impervious (Redevelopment) Is all impervious treated by  disconnection? NOTE: Please include a  copy of the appropriate  STP worksheet(s) with the  application. Tier 2 & 3 Water Quality Practice Shallow Surface Wetland The channel protection standard has not been fully met. Either increase Tv  credit to fully meet HCM or provide extended detention. 24 hours of extended  detention See the Vermont Water Quality Standards for warm and  cold water designations OR The Alternative Extended Detention  Method (§2.2.5.4) is being used. Gravel Wetland #3 Modeling Info: When demonstrating CP compliance with extended detention in a hydrologic model, use the CN and TC  below if the practice being modelled is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Post Development TC (min) Yes No Cold Warm No Yes (WQv met) No Yes No Yes Last Updated 8/28/2018 SN4: Page 8 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Overbank Flood Protection (QP10)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 9.63 Pre‐routed, post‐development peak discharge rate (cfs) 21.20 Routed, post‐development peak discharge rate (cfs) 7.04  Pre‐Development CN (Flow‐ weighted composite)78 18.8 CNAdj 91 11.8 Overbank Flood Notes: Extreme Flood Protection (QP100)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 19.35 Pre‐routed, post‐development peak discharge rate (cfs) 34.12 Routed, post‐development peak discharge rate (cfs) 19.20  Pre‐Development CN (Flow‐ weighted composite)78 18.9 CNAdj 91 12.0 Extreme Flood Notes: The QP10 standard has not been fully met. Provide additional STPs to ensure  post development peak runoff does not exceed pre development peak runoff  for the 10 yr, 24 hour storm event. Gravel Wetland #3 Modeling Info: When demonstrating Q P10  compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP10 is not itself a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) The extreme standard has not been fully met. Provide additional STPs to  ensure post development peak runoff does not exceed pre development peak  runoff for the 100 yr, 24 hour storm event. Gravel Wetland #3 Modeling Info: When demonstrating Q P100 compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP100  is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume achieved  through runoff reduction practices.  The T C  is calculated by the watershed lag method using CN Adj  as CN'. Yes No Yes No Last Updated 8/28/2018 SN4: Page 9 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook General Discharge Point Information Project name Discharge point serial number (e.g. S/N 001) Name of receiving water  Latitude (decimal degrees to five decimal places) Longitude  (decimal degrees to five decimal places) Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Total Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 8.420 8.420 Woods 0.000 0.000 0.000 2.600 2.600 Existing Impervious 0.000 0.000 0.000 0.090 0.090 Impervious previously authorized under 2002 VSMM (not included in calculations)0.000 Total Pre Site Area 11.110 %  Landuse A B C D Total Grass 0.000 0.000 0.000 7.740 7.740 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 New Impervious 0.000 0.000 0.000 3.360 3.360 30.3% Existing for Permit  Coverage (Treated to New  Standards) 0.000 0.000 0.000 0.000 0.000 0.0% Existing Impervious Not for Permit Coverage 0.000 0.0% Redeveloped Impervious 0.000 0.0% 0.000 Total Site Area 11.100 Total Impervious for Permit Coverage 3.360 Net Reduced Impervious 0.000 0.0% Reduced Existing Impervious (for redevelopment)0.090 100.0% Average  Catchment  Slope, Y (%) Hydraulic  Length, l (ft) Pre Development 8.87 1070.00 Post Development 8.87 1070.00 WARNING: Pre development and post development areas don't match, so evaluation of the Hydrologic  Condition Method is not appropriate within this drainage area. Designer may consider HCM across drainage  EASTVIEW S/N 006 Wetlands in Potash Brook Watershed 44.45444 ‐73.15299 * Preciptation values shall be obtained from  Pre Development Land Use (acres) Post Development Land Use (acres) Impervious previously authorized under 2002 VSMM Information for Calculating TC by the  Watershed Lag Method  Last Updated 8/28/2018 SN6: Page 10 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Runoff Calculations 1 yr, 24‐hr 10 yr, 24‐hr 100 yr, 24‐hr 0.3995 1.2122 2.3895 0.7932 1.7740 3.0735 Tier 1/Runoff Reduction Practices Practice TV (ac‐ft) TV (ac‐ft) Simple Disconnection 0.028 Runoff Reduction Calculations Standard Re WQ CP QP10 QP100 TV Required (ac‐ft)0.0000 0.2983 0.3937 0.5617 0.6840 TV Provided (ac‐ft)0.0283 0.0283 0.0283 0.0283 0.0283 TV Remaining (ac‐ft)0.0000 0.2700 0.3654 0.5334 0.6557 Standard met with HCM?n/a No No No No Post‐Development CN n/a 90 88 86 86 CNadj n/a 89 87 86 86 Pre‐Development CN n/a n/a 78 78 78 Groundwater Recharge Standard (Re)2 Standard Applicable? ReV 0.0000 Standard met with Tier 1  Practices? n/a  Recharge Notes: HSG D Soils Predevelopment runoff volume (ac‐ft) Pre‐routed, post development runoff volume (ac‐ft) List all Tier 1 practices below with the associated treatment volume (TV ).  The T V  will be applied to all treatment standards,  except for Green Roofs, which do not receive recharge or water quality credit. Please include the appropriate STP  worksheet(s) with the application. Practice Reason recharge not required  (if No is selected):Yes No Last Updated 8/28/2018 SN6: Page 11 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Water Quality Treatment Standard (WQ)11 (ac‐ft) Apply Reduction? WQV ‐ New & Existing 0.2983 0.0% WQV ‐ Redevelopment 0.0000 100.0% Max 25%  applied Total WQV 0.2983 WQV met with Tier 1  practices 0.0283 1 WQV to be met with Tier 2  and/or Tier 3 practices 0.2700 WQV Provided  (ac‐ft)Tier 0.2700 Tier 2 Total WQV Provided (ac‐ft)0.2700 ac‐ft Is the WQV Standard met?Yes Water Quality Notes: Channel Protection Standard (CP)21 Standard Applicable? Standard Met with HCM?No Provide Extended  Detention for:0.765 ac‐ft Warm or Cold Water  Fishery?→Provide: FALSE Extended Detention STP: CNAdj 87 8.9 (Watershed  Lag Method) Channel Protection Notes: % Net Reduction % Removed Existing  Impervious (Redevelopment) Is all impervious treated by  disconnection? NOTE: Please include a  copy of the appropriate  STP worksheet(s) with the  application. Tier 2 & 3 Water Quality Practice Gravel Wetland The channel protection standard has not been fully met. Either increase Tv  credit to fully meet HCM or provide extended detention. 24 hours of extended  detention See the Vermont Water Quality Standards for warm and  cold water designations OR The Alternative Extended Detention  Method (§2.2.5.4) is being used. Gravel Wetland #4 Modeling Info: When demonstrating CP compliance with extended detention in a hydrologic model, use the CN and TC  below if the practice being modelled is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Post Development TC (min) Yes No Cold Warm No Yes (WQv met) No Yes No Yes Last Updated 8/28/2018 SN6: Page 12 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Overbank Flood Protection (QP10)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 20.51 Pre‐routed, post‐development peak discharge rate (cfs) 34.13 Routed, post‐development peak discharge rate (cfs) 15.00  Pre‐Development CN (Flow‐ weighted composite)78 12.0 CNAdj 86 9.2 Overbank Flood Notes: Extreme Flood Protection (QP100)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 40.72 Pre‐routed, post‐development peak discharge rate (cfs) 56.37 Routed, post‐development peak discharge rate (cfs) 36.77  Pre‐Development CN (Flow‐ weighted composite)78 12.0 CNAdj 86 9.3 Extreme Flood Notes: The QP10 standard has not been fully met. Provide additional STPs to ensure  post development peak runoff does not exceed pre development peak runoff  for the 10 yr, 24 hour storm event. Gravel Wetland #4 Modeling Info: When demonstrating Q P10  compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP10 is not itself a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) The extreme standard has not been fully met. Provide additional STPs to  ensure post development peak runoff does not exceed pre development peak  runoff for the 100 yr, 24 hour storm event. Gravel Wetland #4 Modeling Info: When demonstrating Q P100 compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP100  is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume achieved  through runoff reduction practices.  The T C  is calculated by the watershed lag method using CN Adj  as CN'. Yes No Yes No Last Updated 8/28/2018 SN6: Page 13 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook General Discharge Point Information Project name Discharge point serial number (e.g. S/N 001) Name of receiving water  Latitude (decimal degrees to five decimal places) Longitude  (decimal degrees to five decimal places) Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Total Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 11.480 11.480 Woods 0.000 0.000 0.000 3.980 3.980 Existing Impervious 0.000 0.000 0.000 0.060 0.060 Impervious previously authorized under 2002 VSMM (not included in calculations)0.000 Total Pre Site Area 15.520 %  Landuse A B C D Total Grass 0.000 0.000 0.000 11.540 11.540 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 New Impervious 0.000 0.000 0.000 3.980 3.980 25.6% Existing for Permit  Coverage (Treated to New  Standards) 0.000 0.000 0.000 0.000 0.000 0.0% Existing Impervious Not for Permit Coverage 0.000 0.0% Redeveloped Impervious 0.000 0.0% 0.000 Total Site Area 15.520 Total Impervious for Permit Coverage 3.980 Net Reduced Impervious 0.000 0.0% Reduced Existing Impervious (for redevelopment)0.060 100.0% Average  Catchment  Slope, Y (%) Hydraulic  Length, l (ft) Pre Development 7.31 1490.00 Post Development 7.31 1490.00 EASTVIEW S/N 007 Wetlands in Potash Brook Watershed 44.45584 ‐73.15221 * Preciptation values shall be obtained from  Pre Development Land Use (acres) Post Development Land Use (acres) Impervious previously authorized under 2002 VSMM Information for Calculating TC by the  Watershed Lag Method  Last Updated 8/28/2018 SN7: Page 14 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Runoff Calculations 1 yr, 24‐hr 10 yr, 24‐hr 100 yr, 24‐hr 0.5503 1.6822 3.3244 1.0389 2.3860 4.1866 Tier 1/Runoff Reduction Practices Practice TV (ac‐ft) TV (ac‐ft) Runoff Reduction Calculations Standard Re WQ CP QP10 QP100 TV Required (ac‐ft)0.0000 0.3632 0.4886 0.7038 0.8622 TV Provided (ac‐ft)0.0000 0.0000 0.0000 0.0000 0.0000 TV Remaining (ac‐ft)0.0000 0.3632 0.4886 0.7038 0.8622 Standard met with HCM?n/a No No No No Post‐Development CN n/a 89 87 86 85 CNadj n/a 89 87 86 85 Pre‐Development CN n/a n/a 78 78 78 Groundwater Recharge Standard (Re)2 Standard Applicable? ReV 0.0000 Standard met with Tier 1  Practices? n/a  Recharge Notes: HSG D Soils Predevelopment runoff volume (ac‐ft) Pre‐routed, post development runoff volume (ac‐ft) List all Tier 1 practices below with the associated treatment volume (TV ).  The T V  will be applied to all treatment standards,  except for Green Roofs, which do not receive recharge or water quality credit. Please include the appropriate STP  worksheet(s) with the application. Practice Reason recharge not required  (if No is selected):Yes No Last Updated 8/28/2018 SN7: Page 15 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Water Quality Treatment Standard (WQ)11 (ac‐ft) Apply Reduction? WQV ‐ New & Existing 0.3632 0.0% WQV ‐ Redevelopment 0.0000 100.0% Max 25%  applied Total WQV 0.3632 WQV met with Tier 1  practices 0.0000 1 WQV to be met with Tier 2  and/or Tier 3 practices 0.3632 WQV Provided  (ac‐ft)Tier 0.3632 Tier 2 Total WQV Provided (ac‐ft)0.3632 ac‐ft Is the WQV Standard met?Yes Water Quality Notes: Channel Protection Standard (CP)21 Standard Applicable? Standard Met with HCM?No Provide Extended  Detention for:1.039 ac‐ft Warm or Cold Water  Fishery?→Provide: FALSE Extended Detention STP: CNAdj 87 13.0 (Watershed  Lag Method) Channel Protection Notes: % Net Reduction % Removed Existing  Impervious (Redevelopment) Is all impervious treated by  disconnection? NOTE: Please include a  copy of the appropriate  STP worksheet(s) with the  application. Tier 2 & 3 Water Quality Practice Gravel Wetland The channel protection standard has not been fully met. Either increase Tv  credit to fully meet HCM or provide extended detention. 24 hours of extended  detention See the Vermont Water Quality Standards for warm and  cold water designations OR The Alternative Extended Detention  Method (§2.2.5.4) is being used. Gravel Wetland #5 Modeling Info: When demonstrating CP compliance with extended detention in a hydrologic model, use the CN and TC  below if the practice being modelled is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Post Development TC (min) Yes No Cold Warm No Yes (WQv met) No Yes No Yes Last Updated 8/28/2018 SN7: Page 16 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Overbank Flood Protection (QP10)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 23.99 Pre‐routed, post‐development peak discharge rate (cfs) 39.77 Routed, post‐development peak discharge rate (cfs) 13.45  Pre‐Development CN (Flow‐ weighted composite)78 17.3 CNAdj 86 13.4 Overbank Flood Notes: Extreme Flood Protection (QP100)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 48.07 Pre‐routed, post‐development peak discharge rate (cfs) 66.81 Routed, post‐development peak discharge rate (cfs) 45.19  Pre‐Development CN (Flow‐ weighted composite)78 17.3 CNAdj 85 13.7 Extreme Flood Notes: The QP10 standard has not been fully met. Provide additional STPs to ensure  post development peak runoff does not exceed pre development peak runoff  for the 10 yr, 24 hour storm event. Gravel Wetland #5 Modeling Info: When demonstrating Q P10  compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP10 is not itself a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) The extreme standard has not been fully met. Provide additional STPs to  ensure post development peak runoff does not exceed pre development peak  runoff for the 100 yr, 24 hour storm event. Gravel Wetland #5 Modeling Info: When demonstrating Q P100 compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP100  is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume achieved  through runoff reduction practices.  The T C  is calculated by the watershed lag method using CN Adj  as CN'. Yes No Yes No Last Updated 8/28/2018 SN7: Page 17 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook General Discharge Point Information Project name Discharge point serial number (e.g. S/N 001) Name of receiving water  Latitude (decimal degrees to five decimal places) Longitude  (decimal degrees to five decimal places) Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Total Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 9.200 9.200 Existing Impervious 0.000 0.000 0.000 0.000 0.000 Impervious previously authorized under 2002 VSMM (not included in calculations)0.000 Total Pre Site Area 9.200 %  Landuse A B C D Total Grass 0.000 0.000 0.000 4.810 4.810 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 New Impervious 0.000 0.000 0.000 4.390 4.390 47.7% Existing for Permit  Coverage (Treated to New  Standards) 0.000 0.000 0.000 0.000 0.000 0.0% Existing Impervious Not for Permit Coverage 0.000 0.0% Redeveloped Impervious 0.000 0.0% 0.000 Total Site Area 9.200 Total Impervious for Permit Coverage 4.390 Net Reduced Impervious 0.000 0.0% Reduced Existing Impervious (for redevelopment)0.000 0.0% Average  Catchment  Slope, Y (%) Hydraulic  Length, l (ft) Pre Development 9.35 1250.00 Post Development 9.35 1250.00 EASTVIEW S/N 008 Wetlands in Potash Brook Watershed 44.45650 ‐73.15097 * Preciptation values shall be obtained from  Pre Development Land Use (acres) Post Development Land Use (acres) Impervious previously authorized under 2002 VSMM Information for Calculating TC by the  Watershed Lag Method  Last Updated 8/28/2018 SN8: Page 18 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Runoff Calculations 1 yr, 24‐hr 10 yr, 24‐hr 100 yr, 24‐hr 0.3033 0.9565 1.9151 0.8143 1.6812 2.7950 Tier 1/Runoff Reduction Practices Practice TV (ac‐ft) TV (ac‐ft) Runoff Reduction Calculations Standard Re WQ CP QP10 QP100 TV Required (ac‐ft)0.0000 0.3676 0.5111 0.7247 0.8799 TV Provided (ac‐ft)0.0000 0.0000 0.0000 0.0000 0.0000 TV Remaining (ac‐ft)0.0000 0.3676 0.5111 0.7247 0.8799 Standard met with HCM?n/a No No No No Post‐Development CN n/a 94 91 90 89 CNadj n/a 94 91 90 89 Pre‐Development CN n/a n/a 77 77 77 Groundwater Recharge Standard (Re)1 Standard Applicable? ReV 0.0000 Standard met with Tier 1  Practices? n/a  Recharge Notes: Predevelopment runoff volume (ac‐ft) Pre‐routed, post development runoff volume (ac‐ft) List all Tier 1 practices below with the associated treatment volume (TV ).  The T V  will be applied to all treatment standards,  except for Green Roofs, which do not receive recharge or water quality credit. Please include the appropriate STP  worksheet(s) with the application. Practice Yes No Last Updated 8/28/2018 SN8: Page 19 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Water Quality Treatment Standard (WQ)11 (ac‐ft) Apply Reduction? WQV ‐ New & Existing 0.3676 0.0% WQV ‐ Redevelopment 0.0000 0.0% Total WQV 0.3676 WQV met with Tier 1  practices 0.0000 1 WQV to be met with Tier 2  and/or Tier 3 practices 0.3676 WQV Provided  (ac‐ft)Tier 0.3676 Tier 2 Total WQV Provided (ac‐ft)0.3676 ac‐ft Is the WQV Standard met?Yes Water Quality Notes: Channel Protection Standard (CP)21 Standard Applicable? Standard Met with HCM?No Provide Extended  Detention for:0.814 ac‐ft Warm or Cold Water  Fishery?→Provide: FALSE Extended Detention STP: CNAdj 91 8.4 (Watershed  Lag Method) Channel Protection Notes: % Net Reduction % Removed Existing  Impervious (Redevelopment) Is all impervious treated by  disconnection? NOTE: Please include a  copy of the appropriate  STP worksheet(s) with the  application. Tier 2 & 3 Water Quality Practice Gravel Wetland The channel protection standard has not been fully met. Either increase Tv  credit to fully meet HCM or provide extended detention. 24 hours of extended  detention See the Vermont Water Quality Standards for warm and  cold water designations OR The Alternative Extended Detention  Method (§2.2.5.4) is being used. Gravel Wetlands 6A and 6B Modeling Info: When demonstrating CP compliance with extended detention in a hydrologic model, use the CN and TC  below if the practice being modelled is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Post Development TC (min) Yes No Cold Warm No Yes (WQv met) No Yes No Yes Last Updated 8/28/2018 SN8: Page 20 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Overbank Flood Protection (QP10)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 15.72 Pre‐routed, post‐development peak discharge rate (cfs) 32.51 Routed, post‐development peak discharge rate (cfs) 11.50  Pre‐Development CN (Flow‐ weighted composite)77 13.6 CNAdj 90 8.8 Overbank Flood Notes: Extreme Flood Protection (QP100)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 31.87 Pre‐routed, post‐development peak discharge rate (cfs) 52.47 Routed, post‐development peak discharge rate (cfs) 22.05  Pre‐Development CN (Flow‐ weighted composite)77 13.6 CNAdj 89 9.0 Extreme Flood Notes: The QP10 standard has not been fully met. Provide additional STPs to ensure  post development peak runoff does not exceed pre development peak runoff  for the 10 yr, 24 hour storm event. Gravel Wetlands 6A and 6B Modeling Info: When demonstrating Q P10  compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP10 is not itself a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) The extreme standard has not been fully met. Provide additional STPs to  ensure post development peak runoff does not exceed pre development peak  runoff for the 100 yr, 24 hour storm event. Gravel Wetlands #6A and #6B Modeling Info: When demonstrating Q P100 compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP100  is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume achieved  through runoff reduction practices.  The T C  is calculated by the watershed lag method using CN Adj  as CN'. Yes No Yes No Last Updated 8/28/2018 SN8: Page 21 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook General Discharge Point Information Project name Discharge point serial number (e.g. S/N 001) Name of receiving water  Latitude (decimal degrees to five decimal places) Longitude  (decimal degrees to five decimal places) Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Total Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 4.090 4.090 Existing Impervious 0.000 0.000 0.000 0.000 0.000 Impervious previously authorized under 2002 VSMM (not included in calculations)0.000 Total Pre Site Area 4.090 %  Landuse A B C D Total Grass 0.000 0.000 0.000 3.390 3.390 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 New Impervious 0.000 0.000 0.000 0.700 0.700 17.1% Existing for Permit  Coverage (Treated to New  Standards) 0.000 0.000 0.000 0.000 0.000 0.0% Existing Impervious Not for Permit Coverage 0.000 0.0% Redeveloped Impervious 0.000 0.0% 0.000 Total Site Area 4.090 Total Impervious for Permit Coverage 0.700 Net Reduced Impervious 0.000 0.0% Reduced Existing Impervious (for redevelopment)0.000 0.0% Average  Catchment  Slope, Y (%) Hydraulic  Length, l (ft) Pre Development 8.62 680.00 Post Development 8.62 680.00 EASTVIEW S/N 009 Wetlands in Potash Brook Watershed 44.45452 ‐73.14914 * Preciptation values shall be obtained from  Pre Development Land Use (acres) Post Development Land Use (acres) Impervious previously authorized under 2002 VSMM Information for Calculating TC by the  Watershed Lag Method  Last Updated 8/28/2018 SN9: Page 22 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Runoff Calculations 1 yr, 24‐hr 10 yr, 24‐hr 100 yr, 24‐hr 0.1348 0.4252 0.8514 0.2397 0.5829 1.0495 Tier 1/Runoff Reduction Practices Practice TV (ac‐ft) TV (ac‐ft) Runoff Reduction Calculations Standard Re WQ CP QP10 QP100 TV Required (ac‐ft)0.0000 0.0695 0.1049 0.1577 0.1981 TV Provided (ac‐ft)0.0000 0.0000 0.0000 0.0000 0.0000 TV Remaining (ac‐ft)0.0000 0.0695 0.1049 0.1577 0.1981 Standard met with HCM?n/a No No No No Post‐Development CN n/a 86 85 84 83 CNadj n/a 86 85 84 83 Pre‐Development CN n/a n/a 77 77 77 Groundwater Recharge Standard (Re)2 Standard Applicable? ReV 0.0000 Standard met with Tier 1  Practices? n/a  Recharge Notes: HSG D Soils Predevelopment runoff volume (ac‐ft) Pre‐routed, post development runoff volume (ac‐ft) List all Tier 1 practices below with the associated treatment volume (TV ).  The T V  will be applied to all treatment standards,  except for Green Roofs, which do not receive recharge or water quality credit. Please include the appropriate STP  worksheet(s) with the application. Practice Reason recharge not required  (if No is selected):Yes No Last Updated 8/28/2018 SN9: Page 23 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Water Quality Treatment Standard (WQ)11 (ac‐ft) Apply Reduction? WQV ‐ New & Existing 0.0695 0.0% WQV ‐ Redevelopment 0.0000 0.0% Total WQV 0.0695 WQV met with Tier 1  practices 0.0000 1 WQV to be met with Tier 2  and/or Tier 3 practices 0.0695 WQV Provided  (ac‐ft)Tier 0.0695 Total WQV Provided (ac‐ft)0.0695 ac‐ft Is the WQV Standard met?Yes Water Quality Notes: Channel Protection Standard (CP)21 Standard Applicable? Standard Met with HCM?No Provide Extended  Detention for:0.240 ac‐ft Warm or Cold Water  Fishery?→Provide: FALSE Extended Detention STP: CNAdj 85 6.8 (Watershed  Lag Method) Channel Protection Notes: % Net Reduction % Removed Existing  Impervious (Redevelopment) Is all impervious treated by  disconnection? Tier 2 & 3 Water Quality Practice The channel protection standard has not been fully met. Either increase Tv  credit to fully meet HCM or provide extended detention. 24 hours of extended  detention See the Vermont Water Quality Standards for warm and  cold water designations OR The Alternative Extended Detention  Method (§2.2.5.4) is being used. Gravel Wetland #7 Modeling Info: When demonstrating CP compliance with extended detention in a hydrologic model, use the CN and TC  below if the practice being modelled is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Post Development TC (min) Yes No Cold Warm No Yes (WQv met) No Yes No Yes Last Updated 8/28/2018 SN9: Page 24 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Overbank Flood Protection (QP10)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 8.09 Pre‐routed, post‐development peak discharge rate (cfs) 12.69 Routed, post‐development peak discharge rate (cfs) 0.73  Pre‐Development CN (Flow‐ weighted composite)77 8.7 CNAdj 84 7.0 Overbank Flood Notes: Extreme Flood Protection (QP100)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 16.28 Pre‐routed, post‐development peak discharge rate (cfs) 22.24 Routed, post‐development peak discharge rate (cfs) 1.24  Pre‐Development CN (Flow‐ weighted composite)77 8.7 CNAdj 83 7.1 Extreme Flood Notes: The QP10 standard has not been fully met. Provide additional STPs to ensure  post development peak runoff does not exceed pre development peak runoff  for the 10 yr, 24 hour storm event. Gravel Wetland #7 Modeling Info: When demonstrating Q P10  compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP10 is not itself a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) The extreme standard has not been fully met. Provide additional STPs to  ensure post development peak runoff does not exceed pre development peak  runoff for the 100 yr, 24 hour storm event. Gravel Wetland #7 Modeling Info: When demonstrating Q P100 compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP100  is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume achieved  through runoff reduction practices.  The T C  is calculated by the watershed lag method using CN Adj  as CN'. Yes No Yes No Last Updated 8/28/2018 SN9: Page 25 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook General Discharge Point Information Project name Discharge point serial number (e.g. S/N 001) Name of receiving water  Latitude (decimal degrees to five decimal places) Longitude  (decimal degrees to five decimal places) Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Total Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 12.700 12.700 Existing Impervious 0.000 0.000 0.000 0.000 0.000 Impervious previously authorized under 2002 VSMM (not included in calculations)0.000 Total Pre Site Area 12.700 %  Landuse A B C D Total Grass 0.000 0.000 0.000 11.700 11.700 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 New Impervious 0.000 0.000 0.000 1.000 1.000 7.9% Existing for Permit  Coverage (Treated to New  Standards) 0.000 0.000 0.000 0.000 0.000 0.0% Existing Impervious Not for Permit Coverage 0.000 0.0% Redeveloped Impervious 0.000 0.0% 0.000 Total Site Area 12.700 Total Impervious for Permit Coverage 1.000 Net Reduced Impervious 0.000 0.0% Reduced Existing Impervious (for redevelopment)0.000 0.0% Average  Catchment  Slope, Y (%) Hydraulic  Length, l (ft) Pre Development 5.2 960.00 Post Development 5.2 960.00 EASTVIEW S/N 010 Potash Brook 44.45358 ‐73.14810 * Preciptation values shall be obtained from  Pre Development Land Use (acres) Post Development Land Use (acres) Impervious previously authorized under 2002 VSMM Information for Calculating TC by the  Watershed Lag Method  Last Updated 8/28/2018 SN10: Page 26 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Runoff Calculations 1 yr, 24‐hr 10 yr, 24‐hr 100 yr, 24‐hr 0.4186 1.3204 2.6437 0.6296 1.6559 3.0778 Tier 1/Runoff Reduction Practices Practice TV (ac‐ft) TV (ac‐ft) Runoff Reduction Calculations Standard Re WQ CP QP10 QP100 TV Required (ac‐ft)0.0000 0.1279 0.2110 0.3355 0.4341 TV Provided (ac‐ft)0.0000 0.0000 0.0000 0.0000 0.0000 TV Remaining (ac‐ft)0.0000 0.1279 0.2110 0.3355 0.4341 Standard met with HCM?n/a No No No No Post‐Development CN n/a 82 82 82 82 CNadj n/a 82 82 82 82 Pre‐Development CN n/a n/a 77 77 77 Groundwater Recharge Standard (Re)2 Standard Applicable? ReV 0.0000 Standard met with Tier 1  Practices? n/a  Recharge Notes: HSG D Soils Predevelopment runoff volume (ac‐ft) Pre‐routed, post development runoff volume (ac‐ft) List all Tier 1 practices below with the associated treatment volume (TV ).  The T V  will be applied to all treatment standards,  except for Green Roofs, which do not receive recharge or water quality credit. Please include the appropriate STP  worksheet(s) with the application. Practice Reason recharge not required  (if No is selected):Yes No Last Updated 8/28/2018 SN10: Page 27 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Water Quality Treatment Standard (WQ)11 (ac‐ft) Apply Reduction? WQV ‐ New & Existing 0.1279 0.0% WQV ‐ Redevelopment 0.0000 0.0% Total WQV 0.1279 WQV met with Tier 1  practices 0.0000 1 WQV to be met with Tier 2  and/or Tier 3 practices 0.1279 WQV Provided  (ac‐ft)Tier 0.1279 Tier 2 Total WQV Provided (ac‐ft)0.1279 ac‐ft Is the WQV Standard met?Yes Water Quality Notes: Channel Protection Standard (CP)21 Standard Applicable? Standard Met with HCM?No Provide Extended  Detention for:0.630 ac‐ft Warm or Cold Water  Fishery?→Provide: FALSE Extended Detention STP: CNAdj 82 12.5 (Watershed  Lag Method) Channel Protection Notes: % Net Reduction % Removed Existing  Impervious (Redevelopment) Is all impervious treated by  disconnection? NOTE: Please include a  copy of the appropriate  STP worksheet(s) with the  application. Tier 2 & 3 Water Quality Practice Gravel Wetland The channel protection standard has not been fully met. Either increase Tv  credit to fully meet HCM or provide extended detention. 24 hours of extended  detention See the Vermont Water Quality Standards for warm and  cold water designations OR The Alternative Extended Detention  Method (§2.2.5.4) is being used. Gravel Wetland #8 Modeling Info: When demonstrating CP compliance with extended detention in a hydrologic model, use the CN and TC  below if the practice being modelled is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Post Development TC (min) Yes No Cold Warm No Yes (WQv met) No Yes No Yes Last Updated 8/28/2018 SN10: Page 28 of 29 Vermont Operational Stormwater Permit ‐ Standards Compliance Workbook Overbank Flood Protection (QP10)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 20.09 Pre‐routed, post‐development peak discharge rate (cfs) 28.07 Routed, post‐development peak discharge rate (cfs) 5.00  Pre‐Development CN (Flow‐ weighted composite)77 14.8 CNAdj 82 12.7 Overbank Flood Notes: Extreme Flood Protection (QP100)1 Standard Applicable? Standard Met with HCM?No STP used: Pre‐development peak discharge rate (cfs) 41.01 Pre‐routed, post‐development peak discharge rate (cfs) 51.90 Routed, post‐development peak discharge rate (cfs) 28.98  Pre‐Development CN (Flow‐ weighted composite)77 14.8 CNAdj 82 12.8 Extreme Flood Notes: The QP10 standard has not been fully met. Provide additional STPs to ensure  post development peak runoff does not exceed pre development peak runoff  for the 10 yr, 24 hour storm event. Gravel Wetland #8 Modeling Info: When demonstrating Q P10  compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP10 is not itself a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume  achieved through Tier 1 practices.  The T C  is calculated by the watershed lag method using CNAdj  as CN'. Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) Pre Development TC (min)(Watershed  Lag Method)Post Development TC (min) The extreme standard has not been fully met. Provide additional STPs to  ensure post development peak runoff does not exceed pre development peak  runoff for the 100 yr, 24 hour storm event. Gravel Wetland #8 Modeling Info: When demonstrating Q P100 compliance in a hydrologic model, use the following CN and T C  below, if the  practice used to meet QP100  is not a Tier 1 practice.  The CN Adj  takes into account the reduction in runoff volume achieved  through runoff reduction practices.  The T C  is calculated by the watershed lag method using CN Adj  as CN'. Yes No Yes No Last Updated 8/28/2018 SN10: Page 29 of 29 Version: 11/30/2020 Project Name: Discharge Point: Treatment Wetland # Practice Drainage Area For Permit  Coverage Not for Permit  Coverage Total to  Practice 1 Total Area (acres)7.240 0.000 7.240 2 3.090 0.000 3.090 3 0.000 0.000 0.000 WQV for  credit WQV not for  credit Total  WQV  4 WQV to practice 0.2619 0.0000 0.2619 93 5 2 6 2 Response Attachment location 7 Plan Sheet C‐11 8 Detail Sheet D‐9 9 Plan Sheet C‐11, C‐12 10 Detail Sheet D‐8 11*Detail Sheet D‐8 12*Detail Sheet D‐8 13*Detail Sheet D‐8 Response Attachment location 14 Forebay, Sheet C‐11 ↑Enter this value on the Standards  Compliance Workbook Is outlet elevation designed such that a sub‐surface water level is maintained  in the gravel wetland? If the gravel wetland is designed with an organic soil layer at the surface, have  vertical perforated riser pipes been provided to deliver stormwater  stormwater from the surface down to the gravel bed? Have the outfalls and the conveyance to the discharge point been designed  and protected to avoid erosion? Practice Type Redeveloped Impervious Pre‐Treatment (4.3.6.3) Has pretreatment been provided for non‐rooftop runoff?  Discharges to Cold or  Warm Water Fishery? Modified CN for WQ  (1.0ʺ) storm Note: Designers may use the Practice Drainage Area Runoff Calculator (second tab) for calculation of practice‐ specific runoff volumes for other treatment standards. Conveyance (4.3.5.2) Are inlets stabilized to ensure that non‐erosive conditions exist for at least the  1‐year, 24 hour storm? * Questions preceded by an asterix (*) may change based on previously entered values Have inlet pipes been set at the permanent pool or the base of the gravel bed? New Impervious (acres) EASTVIEW 6 4Treatment Wetlands (4.3.5) Has a low for orifice been provided to meet the the WQV and CPV extended  Has a liner designed in accordance with Section 4.3.5.2 been provided if the  infiltration rate exceed 0.05 inches per hour and the wetland is located above  Yes No Yes No No No Yes Yes NoYes Cold Warm NoYes NoYes NoYes Shallow surface wetland Gravel wetland Page 1 of 4 15 Response Attachment location 16 ft3 1319 17 ft3 4592 18 ft3 5911 19* 20* 21 51.8%Yes 22 23 24 ac‐ft 0.513 Enter this on the eNOI Response Attachment location 25 NA, no 4ʹ deep pools 26 NA, no 4ʹ deep pools 27 Detail Sheet D‐8 28 NA 29 Detail Sheet D‐8 30 NA Attachment location: Indicate the specific location (i.e. appendix, page, plan sheet) where the requisite support documentation has  been provided within the application. What is the volume stored in the forebay or other volumetric pre‐ treatment if used? (minimum 10% WQV) What is the volume stored in the permanent pool? What is the total WQV stored at the normal water level (pre‐ treatment + permanent pool)? Does the pre‐treatment volume plus the permanent pool equal at least 50% of  the WQV? Has a planting plan been prepared showing how aquatic and terrestrial areas  will be stabilized, including plant species, plant locations, sources of plant  material and any required soil amendments? Are any donor organic soils used in the practice obtained from a source other  than natural wetlands? Is the remaining WQV provided  for by extended detention over 24 hours? Are all deep pool areas of ≥ 4 feet depth with side slopes steeper than 4:1 (H:V)  surrounded by a safety bench with ≤6% slope  extending 10 feet outward from  the normal water edge to the toe of the side slope? Landscaping (4.3.6.5) Treatment (4.3.6.4) Has a minimum flow path at normal water level of 3:1 been provided? Does the planting plan specify that no woody vegetation >2 inches in diameter  shall be planted or allowed to grow on the dam, within 15 feet of the dam or  the toe of the embankment, or within 25 of a principal spillway outlet? What type of pretreatment is being  used? Has an aquatic been been provided that extends at least 5 feet inward from the  normal water edge and is no more than 18 inches deep? Has a setback been provided that extends 25 feet from the maximum design  water surface elevation of the practice? What is the Storage Volume of the practice. Include the permanent  pool and any volume used for providing extended detention. Swale Filter Strip Forebay (10% WQv) Deep Sump Catch Basins Proprietary NoYes NoYes NoYes Yes No NoYes NoYes NoYes NoYes NoYes NoYes Page 2 of 4 Practice Drainage Area Runoff Calculator Project Name: Discharge Point: Treatment Wetland # Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 4.550 4.550 Woods 0.000 0.000 0.000 2.600 2.600 Pavement, roofs, and  other impervious 0.000 0.000 0.000 0.090 0.090 Total 0.000 0.000 0.000 7.240 7.240 Landuse A B C D Grass 0.000 0.000 0.000 4.150 4.060 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 Pavement, roofs, and  other impervious 0.000 0.000 0.000 3.090 3.090 Total 0.000 0.000 0.000 7.240 7.240 TV of upstream practices:0.000 ac‐ft TV credit of this practice:0.000 ac‐ft Treatment Standard Required  Treatment  Volume Post  Development  Runoff  Volume Pre‐ development  Runoff  Volume Post  Composite CN  (to practice) CNAdj (with TV  practice  credit) Pre  Composite  CN Channel Protection  (Hydrologic Condition  Method) 0.3441 0.6052 0.2611 90 90 78 Overbank Flood 0.4854 1.2751 0.7897 89 89 78 Extreme Flood 0.5874 2.1433 1.5559 88 88 78 Information for Calculating TC by the Watershed Lag Method  1 yr 10 yr 100 yr Time of Concentration, TC (min)Hydraulic  Length, l (ft) Average  Catchment  Slope, Y (%) EASTVIEW 6 4 Hydrologic Soil Group Total (acres) This tool may be used to calculate the required treatment volumes for the area draining to an individual practice  where the practices drainage area is only a portion of of the area draining to a discharge point. Where the practice  receives runoff from the entire area to a discharge point, this calculator will give the same information as the  Standards Compliance Workbook. * Preciptation values shall be obtained from  Pre Development Land Use (acres) Hydrologic Soil Group Total (acres) Post Development Land Use (acres) Pre Development 8.87% 1070.00 11.9 12.0 12.0 Post Development,  upstream of practice 8.87% 1070.00 7.9 8.3 8.5 Post Development, with  TV credit from practice 0.00% 0.00 0.0 0.0 0.0 Version: 11/30/2020 Project Name: Discharge Point: Treatment Wetland # Practice Drainage Area For Permit  Coverage Not for Permit  Coverage Total to  Practice 1 Total Area (acres)15.520 0.000 15.520 2 4.180 0.000 4.180 3 0.000 0.000 0.000 WQV for  credit WQV not for  credit Total  WQV  4 WQV to practice 0.3782 0.0000 0.3782 89 5 2 6 2 Response Attachment location 7 Plan Sheet C‐14 8 Detail Sheet D‐9 9 Plan Sheet C‐14 10 Detail Sheet D‐8 11*Detail Sheet D‐8 12*Detail Sheet D‐8 13*Detail Sheet D‐8 Response Attachment location 14 Forebay, Sheet C‐14 11 Has a liner designed in accordance with Section 4.3.5.2 been provided if the  infiltration rate exceed 0.05 inches per hour and the wetland is located above  New Impervious (acres) EASTVIEW 7 5Treatment Wetlands (4.3.5) Redeveloped Impervious Pre‐Treatment (4.3.6.3) Has pretreatment been provided for non‐rooftop runoff?  Discharges to Cold or  Warm Water Fishery? Modified CN for WQ  (1.0ʺ) storm Note: Designers may use the Practice Drainage Area Runoff Calculator (second tab) for calculation of practice‐ specific runoff volumes for other treatment standards. Conveyance (4.3.5.2) Are inlets stabilized to ensure that non‐erosive conditions exist for at least the  1‐year, 24 hour storm? * Questions preceded by an asterix (*) may change based on previously entered values Have inlet pipes been set at the permanent pool or the base of the gravel bed? ↑Enter this value on the Standards  Compliance Workbook Is outlet elevation designed such that a sub‐surface water level is maintained  in the gravel wetland? If the gravel wetland is designed with an organic soil layer at the surface, have  vertical perforated riser pipes been provided to deliver stormwater  stormwater from the surface down to the gravel bed? Have the outfalls and the conveyance to the discharge point been designed  and protected to avoid erosion? Practice Type Yes No Yes No No No Yes Yes NoYes Cold Warm NoYes NoYes NoYes Shallow surface wetland Gravel wetland Page 1 of 4 15 Response Attachment location 16 ft3 2601 17 ft3 8631 18 ft3 11232 19* 20* 21 68.2%Yes 22 23 24 ac‐ft 0.917 Enter this on the eNOI Response Attachment location 25 NA, no 4ʹ deep pools 26 NA, no 4ʹ deep pools 27 Detail Sheet D‐8 28 NA 29 Detail Sheet D‐8 30 NA Does the planting plan specify that no woody vegetation >2 inches in diameter  shall be planted or allowed to grow on the dam, within 15 feet of the dam or  the toe of the embankment, or within 25 of a principal spillway outlet? What type of pretreatment is being  used? Has an aquatic been been provided that extends at least 5 feet inward from the  normal water edge and is no more than 18 inches deep? Has a setback been provided that extends 25 feet from the maximum design  water surface elevation of the practice? What is the Storage Volume of the practice. Include the permanent  pool and any volume used for providing extended detention. Are all deep pool areas of ≥ 4 feet depth with side slopes steeper than 4:1 (H:V)  surrounded by a safety bench with ≤6% slope  extending 10 feet outward from  the normal water edge to the toe of the side slope? Landscaping (4.3.6.5) Treatment (4.3.6.4) Has a minimum flow path at normal water level of 3:1 been provided? Attachment location: Indicate the specific location (i.e. appendix, page, plan sheet) where the requisite support documentation has  been provided within the application. What is the volume stored in the forebay or other volumetric pre‐ treatment if used? (minimum 10% WQV) What is the volume stored in the permanent pool? What is the total WQV stored at the normal water level (pre‐ treatment + permanent pool)? Does the pre‐treatment volume plus the permanent pool equal at least 50% of  the WQV? Has a planting plan been prepared showing how aquatic and terrestrial areas  will be stabilized, including plant species, plant locations, sources of plant  material and any required soil amendments? Are any donor organic soils used in the practice obtained from a source other  than natural wetlands? Is the remaining WQV provided  for by extended detention over 24 hours? Swale Filter Strip Forebay (10% WQv) Deep Sump Catch Basins Proprietary NoYes NoYes NoYes Yes No NoYes NoYes NoYes NoYes NoYes NoYes Page 2 of 4 Practice Drainage Area Runoff Calculator Project Name: Discharge Point: Treatment Wetland # Precipitation Data NOAA Atlas 14 Storm WQ Storm 1 yr, 24 hr 10 yr, 24 hr 100 yr, 24 hr Precipitation (inches) 1.00 1.90 3.25 4.85 Drainage Area Information Landuse A B C D Grass 0.000 0.000 0.000 0.000 0.000 Meadow 0.000 0.000 0.000 11.280 11.280 Woods 0.000 0.000 0.000 4.180 4.180 Pavement, roofs, and  other impervious 0.000 0.000 0.000 0.060 0.060 Total 0.000 0.000 0.000 15.520 15.520 Landuse A B C D Grass 0.000 0.000 0.000 11.540 11.540 Meadow 0.000 0.000 0.000 0.000 0.000 Woods 0.000 0.000 0.000 0.000 0.000 Pavement, roofs, and  other impervious 0.000 0.000 0.000 4.180 4.180 Total 0.000 0.000 0.000 15.720 15.720 TV of upstream practices:0.000 ac‐ft TV credit of this practice:0.000 ac‐ft Treatment Standard Required  Treatment  Volume Post  Development  Runoff  Volume Pre‐ development  Runoff  Volume Post  Composite CN  (to practice) CNAdj (with TV  practice  credit) Pre  Composite  CN Channel Protection  (Hydrologic Condition  Method) 0.5171 1.0669 0.5498 87 87 78 Overbank Flood 0.7551 2.4363 1.6812 86 86 78 Extreme Flood 0.9406 4.2635 3.3230 85 85 78 Information for Calculating TC by the Watershed Lag Method  1 yr 10 yr 100 yr Time of Concentration, TC (min)Hydraulic  Length, l (ft) Average  Catchment  Slope, Y (%) Eastview 7 5 Hydrologic Soil Group Total (acres) This tool may be used to calculate the required treatment volumes for the area draining to an individual practice  where the practices drainage area is only a portion of of the area draining to a discharge point. Where the practice  receives runoff from the entire area to a discharge point, this calculator will give the same information as the  Standards Compliance Workbook. * Preciptation values shall be obtained from  Pre Development Land Use (acres) Hydrologic Soil Group Total (acres) Post Development Land Use (acres) Pre Development 7.31% 1490.00 17.3 17.3 17.3 Post Development,  upstream of practice 7.31% 1490.00 12.9 13.3 13.6 Post Development, with  TV credit from practice 0.00% 0.00 0.0 0.0 0.0 230S GW4 231S GW5 224P GravelWet4 254P GravelWet5 Routing Diagram for Eastview2023-postPrepared by Krebs & Lansing Consulting Engineers, Inc., Printed 7/8/2024 HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Subcat Reach Pond Link Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 2HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Project Notes EASTVIEW Old Farm Road & Kimball Avenue South Burlington, Vermont Post Development Stormwater Model Type II 24-hr WQv-1inch Rainfall=1.00"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 3HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 230S: GW4 Runoff = 5.44 cfs @ 12.00 hrs, Volume= 0.272 af, Depth= 0.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr WQv-1inch Rainfall=1.00" Area (ac) CN Description * 7.240 93 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 Direct Entry, Workbook- Lag Subcatchment 230S: GW4 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 6 5 4 3 2 1 0 Type II 24-hr WQv-1inch Rainfall=1.00" Runoff Area=7.240 ac Runoff Volume=0.272 af Runoff Depth=0.45" Tc=7.9 min CN=93 5.44 cfs Type II 24-hr WQv-1inch Rainfall=1.00"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 4HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 231S: GW5 Runoff = 5.81 cfs @ 12.06 hrs, Volume= 0.369 af, Depth= 0.28" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr WQv-1inch Rainfall=1.00" Area (ac) CN Description * 15.520 89 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.0 Direct Entry, Workbook- Lag Subcatchment 231S: GW5 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 6 5 4 3 2 1 0 Type II 24-hr WQv-1inch Rainfall=1.00" Runoff Area=15.520 ac Runoff Volume=0.369 af Runoff Depth=0.28" Tc=13.0 min CN=89 5.81 cfs Type II 24-hr WQv-1inch Rainfall=1.00"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 5HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 224P: GravelWet4 Inflow Area = 7.240 ac, Inflow Depth = 0.45" for WQv-1inch event Inflow = 5.44 cfs @ 12.00 hrs, Volume= 0.272 af Outflow = 0.18 cfs @ 14.63 hrs, Volume= 0.272 af, Atten= 97%, Lag= 157.7 min Primary = 0.18 cfs @ 14.63 hrs, Volume= 0.272 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 377.67' Surf.Area= 11,136 sf Storage= 5,379 cf Peak Elev= 378.95' @ 14.63 hrs Surf.Area= 19,171 sf Storage= 11,992 cf (6,614 cf above start) Plug-Flow detention time= 858.7 min calculated for 0.148 af (55% of inflow) Center-of-Mass det. time= 447.6 min ( 1,286.9 - 839.4 ) Volume Invert Avail.Storage Storage Description #1 375.00' 5,189 cf Custom Stage Data (Prismatic) Listed below (Recalc) 12,973 cf Overall x 40.0% Voids #2 377.33' 373 cf Custom Stage Data (Prismatic) Listed below (Recalc) 3,731 cf Overall x 10.0% Voids #3 378.00' 38,456 cf Custom Stage Data (Prismatic) Listed below (Recalc) 44,018 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 375.00 5,568 0 0 377.33 5,568 12,973 12,973 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 377.33 5,568 0 0 378.00 5,568 3,731 3,731 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 378.00 5,568 0 0 379.00 8,177 6,873 6,873 380.00 9,713 8,945 15,818 381.00 11,305 10,509 26,327 382.00 12,953 12,129 38,456 Device Routing Invert Outlet Devices #1 Primary 377.67'18.0" Round Culvert L= 15.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 377.67' / 376.00' S= 0.1113 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 377.67'2.5" Vert. Orifice/Grate C= 0.600 #3 Device 1 379.00'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 380.10'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 381.25'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Type II 24-hr WQv-1inch Rainfall=1.00"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 6HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=0.18 cfs @ 14.63 hrs HW=378.95' (Free Discharge) 1=Culvert (Passes 0.18 cfs of 4.86 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.18 cfs @ 5.21 fps) 3=Orifice/Grate ( Controls 0.00 cfs) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Pond 224P: GravelWet4 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 6 5 4 3 2 1 0 Inflow Area=7.240 ac Peak Elev=378.95' Storage=11,992 cf 5.44 cfs 0.18 cfs Type II 24-hr WQv-1inch Rainfall=1.00"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 7HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 254P: GravelWet5 Inflow Area = 15.520 ac, Inflow Depth = 0.28" for WQv-1inch event Inflow = 5.81 cfs @ 12.06 hrs, Volume= 0.369 af Outflow = 0.22 cfs @ 15.82 hrs, Volume= 0.369 af, Atten= 96%, Lag= 225.6 min Primary = 0.22 cfs @ 15.82 hrs, Volume= 0.369 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 364.67' Surf.Area= 17,280 sf Storage= 8,346 cf Peak Elev= 365.82' @ 15.82 hrs Surf.Area= 29,209 sf Storage= 17,070 cf (8,724 cf above start) Plug-Flow detention time= 986.1 min calculated for 0.177 af (48% of inflow) Center-of-Mass det. time= 487.2 min ( 1,360.3 - 873.2 ) Volume Invert Avail.Storage Storage Description #1 362.00' 8,052 cf Custom Stage Data (Prismatic) Listed below (Recalc) 20,131 cf Overall x 40.0% Voids #2 364.33' 579 cf Custom Stage Data (Prismatic) Listed below (Recalc) 5,789 cf Overall x 10.0% Voids #3 365.00' 64,384 cf Custom Stage Data (Prismatic) Listed below (Recalc) 73,015 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 362.00 8,640 0 0 364.33 8,640 20,131 20,131 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 364.33 8,640 0 0 365.00 8,640 5,789 5,789 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 365.00 8,640 0 0 366.00 12,649 10,645 10,645 367.00 14,154 13,402 24,046 368.00 15,717 14,936 38,982 369.00 17,336 16,527 55,508 369.50 18,166 8,876 64,384 Device Routing Invert Outlet Devices #1 Primary 364.67'18.0" Round Culvert L= 37.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 364.67' / 358.00' S= 0.1803 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 364.67'2.9" Vert. Orifice/Grate C= 0.600 #3 Device 1 365.83'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 367.50'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 368.00'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 Type II 24-hr WQv-1inch Rainfall=1.00"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 8HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=0.22 cfs @ 15.82 hrs HW=365.82' (Free Discharge) 1=Culvert (Passes 0.22 cfs of 4.19 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.22 cfs @ 4.89 fps) 3=Orifice/Grate ( Controls 0.00 cfs) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Pond 254P: GravelWet5 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 6 5 4 3 2 1 0 Inflow Area=15.520 ac Peak Elev=365.82' Storage=17,070 cf 5.81 cfs 0.22 cfs 247S GW5 258S GW4 246P GravelWet4 255P GravelWet5 Routing Diagram for Eastview2023-postPrepared by Krebs & Lansing Consulting Engineers, Inc., Printed 7/8/2024 HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Subcat Reach Pond Link Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 2HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Project Notes EASTVIEW Old Farm Road & Kimball Avenue South Burlington, Vermont Post Development Stormwater Model Type II 24-hr 1 Year Rainfall=1.90"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 3HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 247S: GW5 Runoff = 17.77 cfs @ 12.06 hrs, Volume= 1.071 af, Depth= 0.83" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 1 Year Rainfall=1.90" Area (ac) CN Description * 15.520 87 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.0 Direct Entry, Workbook- Lag Subcatchment 247S: GW5 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 1 Year Rainfall=1.90" Runoff Area=15.520 ac Runoff Volume=1.071 af Runoff Depth=0.83" Tc=13.0 min CN=87 17.77 cfs Type II 24-hr 1 Year Rainfall=1.90"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 4HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 258S: GW4 Runoff = 12.14 cfs @ 12.00 hrs, Volume= 0.609 af, Depth= 1.01" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 1 Year Rainfall=1.90" Area (ac) CN Description * 7.240 90 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 Direct Entry, Workbook- Lag Subcatchment 258S: GW4 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 1 Year Rainfall=1.90" Runoff Area=7.240 ac Runoff Volume=0.609 af Runoff Depth=1.01" Tc=7.9 min CN=90 12.14 cfs Type II 24-hr 1 Year Rainfall=1.90"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 5HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 246P: GravelWet4 Inflow Area = 7.240 ac, Inflow Depth = 1.01" for 1 Year event Inflow = 12.14 cfs @ 12.00 hrs, Volume= 0.609 af Outflow = 0.28 cfs @ 15.90 hrs, Volume= 0.609 af, Atten= 98%, Lag= 234.3 min Primary = 0.28 cfs @ 15.90 hrs, Volume= 0.609 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 377.67' Surf.Area= 11,136 sf Storage= 5,379 cf Peak Elev= 380.08' @ 15.90 hrs Surf.Area= 20,976 sf Storage= 22,163 cf (16,784 cf above start) Plug-Flow detention time= 1,014.0 min calculated for 0.485 af (80% of inflow) Center-of-Mass det. time= 741.9 min ( 1,569.3 - 827.4 ) Volume Invert Avail.Storage Storage Description #1 375.00' 5,189 cf Custom Stage Data (Prismatic) Listed below (Recalc) 12,973 cf Overall x 40.0% Voids #2 377.33' 373 cf Custom Stage Data (Prismatic) Listed below (Recalc) 3,731 cf Overall x 10.0% Voids #3 378.00' 38,456 cf Custom Stage Data (Prismatic) Listed below (Recalc) 44,018 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 375.00 5,568 0 0 377.33 5,568 12,973 12,973 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 377.33 5,568 0 0 378.00 5,568 3,731 3,731 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 378.00 5,568 0 0 379.00 8,177 6,873 6,873 380.00 9,713 8,945 15,818 381.00 11,305 10,509 26,327 382.00 12,953 12,129 38,456 Device Routing Invert Outlet Devices #1 Primary 377.67'18.0" Round Culvert L= 15.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 377.67' / 376.00' S= 0.1113 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 377.67'2.5" Vert. Orifice/Grate C= 0.600 #3 Device 1 379.00'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 380.10'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 381.25'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Type II 24-hr 1 Year Rainfall=1.90"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 6HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=0.28 cfs @ 15.90 hrs HW=380.08' (Free Discharge) 1=Culvert (Passes 0.28 cfs of 8.65 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.25 cfs @ 7.31 fps) 3=Orifice/Grate (Orifice Controls 0.03 cfs @ 4.91 fps) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Pond 246P: GravelWet4 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=7.240 ac Peak Elev=380.08' Storage=22,163 cf 12.14 cfs 0.28 cfs Type II 24-hr 1 Year Rainfall=1.90"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 7HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 255P: GravelWet5 Inflow Area = 15.520 ac, Inflow Depth = 0.83" for 1 Year event Inflow = 17.77 cfs @ 12.06 hrs, Volume= 1.071 af Outflow = 0.39 cfs @ 18.26 hrs, Volume= 1.071 af, Atten= 98%, Lag= 372.0 min Primary = 0.39 cfs @ 18.26 hrs, Volume= 1.071 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 364.67' Surf.Area= 17,280 sf Storage= 8,346 cf Peak Elev= 367.47' @ 18.26 hrs Surf.Area= 32,169 sf Storage= 39,509 cf (31,162 cf above start) Plug-Flow detention time= 1,245.7 min calculated for 0.879 af (82% of inflow) Center-of-Mass det. time= 963.5 min ( 1,809.8 - 846.3 ) Volume Invert Avail.Storage Storage Description #1 362.00' 8,052 cf Custom Stage Data (Prismatic) Listed below (Recalc) 20,131 cf Overall x 40.0% Voids #2 364.33' 579 cf Custom Stage Data (Prismatic) Listed below (Recalc) 5,789 cf Overall x 10.0% Voids #3 365.00' 64,384 cf Custom Stage Data (Prismatic) Listed below (Recalc) 73,015 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 362.00 8,640 0 0 364.33 8,640 20,131 20,131 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 364.33 8,640 0 0 365.00 8,640 5,789 5,789 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 365.00 8,640 0 0 366.00 12,649 10,645 10,645 367.00 14,154 13,402 24,046 368.00 15,717 14,936 38,982 369.00 17,336 16,527 55,508 369.50 18,166 8,876 64,384 Device Routing Invert Outlet Devices #1 Primary 364.67'18.0" Round Culvert L= 37.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 364.67' / 358.00' S= 0.1803 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 364.67'2.9" Vert. Orifice/Grate C= 0.600 #3 Device 1 365.85'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 367.50'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 368.00'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 Type II 24-hr 1 Year Rainfall=1.90"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 8HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=0.39 cfs @ 18.26 hrs HW=367.47' (Free Discharge) 1=Culvert (Passes 0.39 cfs of 9.62 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.36 cfs @ 7.88 fps) 3=Orifice/Grate (Orifice Controls 0.03 cfs @ 6.05 fps) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Pond 255P: GravelWet5 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=15.520 ac Peak Elev=367.47' Storage=39,509 cf 17.77 cfs 0.39 cfs 249S GW5 253S Post4A 261S GW4 248P GravelWet4 253P GravelWet5 251L SN006 252L SN007 Routing Diagram for Eastview2023-postPrepared by Krebs & Lansing Consulting Engineers, Inc., Printed 7/8/2024 HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Subcat Reach Pond Link Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 2HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Project Notes EASTVIEW Old Farm Road & Kimball Avenue South Burlington, Vermont Post Development Stormwater Model Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 3HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 249S: GW5 Runoff = 39.77 cfs @ 12.05 hrs, Volume= 2.430 af, Depth= 1.88" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 10 Year Rainfall=3.25" Area (ac) CN Description * 15.520 86 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.4 Direct Entry, Workbook- Lag Subcatchment 249S: GW5 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type II 24-hr 10 Year Rainfall=3.25" Runoff Area=15.520 ac Runoff Volume=2.430 af Runoff Depth=1.88" Tc=13.4 min CN=86 39.77 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 4HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 253S: Post4A Runoff = 9.43 cfs @ 12.03 hrs, Volume= 0.530 af, Depth= 1.58" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 10 Year Rainfall=3.25" Area (ac) CN Description * 4.030 82 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.1 Direct Entry, Workbook- Lag Subcatchment 253S: Post4A Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 10 Year Rainfall=3.25" Runoff Area=4.030 ac Runoff Volume=0.530 af Runoff Depth=1.58" Tc=11.1 min CN=82 9.43 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 5HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 261S: GW4 Runoff = 24.70 cfs @ 12.00 hrs, Volume= 1.283 af, Depth= 2.13" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 10 Year Rainfall=3.25" Area (ac) CN Description * 7.240 89 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.3 Direct Entry, Workbook- Lag Subcatchment 261S: GW4 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type II 24-hr 10 Year Rainfall=3.25" Runoff Area=7.240 ac Runoff Volume=1.283 af Runoff Depth=2.13" Tc=8.3 min CN=89 24.70 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 6HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 248P: GravelWet4 Inflow Area = 7.240 ac, Inflow Depth = 2.13" for 10 Year event Inflow = 24.70 cfs @ 12.00 hrs, Volume= 1.283 af Outflow = 7.19 cfs @ 12.15 hrs, Volume= 1.283 af, Atten= 71%, Lag= 9.4 min Primary = 7.19 cfs @ 12.15 hrs, Volume= 1.283 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 377.67' Surf.Area= 11,136 sf Storage= 5,379 cf Peak Elev= 380.87' @ 12.15 hrs Surf.Area= 22,234 sf Storage= 30,430 cf (25,052 cf above start) Plug-Flow detention time= 544.7 min calculated for 1.160 af (90% of inflow) Center-of-Mass det. time= 435.4 min ( 1,244.9 - 809.5 ) Volume Invert Avail.Storage Storage Description #1 375.00' 5,189 cf Custom Stage Data (Prismatic) Listed below (Recalc) 12,973 cf Overall x 40.0% Voids #2 377.33' 373 cf Custom Stage Data (Prismatic) Listed below (Recalc) 3,731 cf Overall x 10.0% Voids #3 378.00' 38,456 cf Custom Stage Data (Prismatic) Listed below (Recalc) 44,018 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 375.00 5,568 0 0 377.33 5,568 12,973 12,973 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 377.33 5,568 0 0 378.00 5,568 3,731 3,731 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 378.00 5,568 0 0 379.00 8,177 6,873 6,873 380.00 9,713 8,945 15,818 381.00 11,305 10,509 26,327 382.00 12,953 12,129 38,456 Device Routing Invert Outlet Devices #1 Primary 377.67'18.0" Round Culvert L= 15.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 377.67' / 376.00' S= 0.1113 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 377.67'2.5" Vert. Orifice/Grate C= 0.600 #3 Device 1 379.00'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 380.10'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 381.25'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 7HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=7.20 cfs @ 12.15 hrs HW=380.87' (Free Discharge) 1=Culvert (Passes 7.20 cfs of 10.51 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.29 cfs @ 8.47 fps) 3=Orifice/Grate (Orifice Controls 0.04 cfs @ 6.51 fps) 4=Orifice/Grate (Orifice Controls 6.87 cfs @ 3.44 fps) 5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Pond 248P: GravelWet4 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=7.240 ac Peak Elev=380.87' Storage=30,430 cf 24.70 cfs 7.19 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 8HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 253P: GravelWet5 Inflow Area = 15.520 ac, Inflow Depth = 1.88" for 10 Year event Inflow = 39.77 cfs @ 12.05 hrs, Volume= 2.430 af Outflow = 13.45 cfs @ 12.26 hrs, Volume= 2.430 af, Atten= 66%, Lag= 12.6 min Primary = 13.45 cfs @ 12.26 hrs, Volume= 2.430 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 364.67' Surf.Area= 17,280 sf Storage= 8,346 cf Peak Elev= 368.41' @ 12.26 hrs Surf.Area= 33,653 sf Storage= 54,118 cf (45,772 cf above start) Plug-Flow detention time= 614.0 min calculated for 2.238 af (92% of inflow) Center-of-Mass det. time= 517.4 min ( 1,343.0 - 825.6 ) Volume Invert Avail.Storage Storage Description #1 362.00' 8,052 cf Custom Stage Data (Prismatic) Listed below (Recalc) 20,131 cf Overall x 40.0% Voids #2 364.33' 579 cf Custom Stage Data (Prismatic) Listed below (Recalc) 5,789 cf Overall x 10.0% Voids #3 365.00' 64,384 cf Custom Stage Data (Prismatic) Listed below (Recalc) 73,015 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 362.00 8,640 0 0 364.33 8,640 20,131 20,131 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 364.33 8,640 0 0 365.00 8,640 5,789 5,789 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 365.00 8,640 0 0 366.00 12,649 10,645 10,645 367.00 14,154 13,402 24,046 368.00 15,717 14,936 38,982 369.00 17,336 16,527 55,508 369.50 18,166 8,876 64,384 Device Routing Invert Outlet Devices #1 Primary 364.67'18.0" Round Culvert L= 37.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 364.67' / 358.00' S= 0.1803 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 364.67'2.8" Vert. Orifice/Grate C= 0.600 #3 Device 1 365.83'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 367.50'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 368.00'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 9HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=13.43 cfs @ 12.26 hrs HW=368.41' (Free Discharge) 1=Culvert (Passes 8.18 cfs of 11.61 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.39 cfs @ 9.16 fps) 3=Orifice/Grate (Orifice Controls 0.04 cfs @ 7.66 fps) 4=Orifice/Grate (Orifice Controls 7.75 cfs @ 3.87 fps) 5=Broad-Crested Rectangular Weir (Weir Controls 5.25 cfs @ 1.62 fps) Pond 253P: GravelWet5 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=15.520 ac Peak Elev=368.41' Storage=54,118 cf 39.77 cfs 13.45 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 10HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 251L: SN006 Inflow Area = 11.270 ac, Inflow Depth = 1.93" for 10 Year event Inflow = 15.00 cfs @ 12.07 hrs, Volume= 1.814 af Primary = 15.00 cfs @ 12.07 hrs, Volume= 1.814 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Link 251L: SN006 Inflow Primary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=11.270 ac 15.00 cfs15.00 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 11HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 252L: SN007 Inflow Area = 15.520 ac, Inflow Depth = 1.88" for 10 Year event Inflow = 13.45 cfs @ 12.26 hrs, Volume= 2.430 af Primary = 13.45 cfs @ 12.26 hrs, Volume= 2.430 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Link 252L: SN007 Inflow Primary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=15.520 ac 13.45 cfs13.45 cfs 245S Post4A 251S GW5 263S GW4 250P GravelWet4 252P GravelWet5 246L Sn006 247L Sn007 Routing Diagram for Eastview2023-postPrepared by Krebs & Lansing Consulting Engineers, Inc., Printed 7/8/2024 HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Subcat Reach Pond Link Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 2HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Project Notes EASTVIEW Old Farm Road & Kimball Avenue South Burlington, Vermont Post Development Stormwater Model Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 3HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 245S: Post4A Runoff = 17.44 cfs @ 12.03 hrs, Volume= 0.989 af, Depth= 2.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 100 Year Rainfall=4.85" Area (ac) CN Description * 4.030 82 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.1 Direct Entry, Workbook- Lag Subcatchment 245S: Post4A Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 100 Year Rainfall=4.85" Runoff Area=4.030 ac Runoff Volume=0.989 af Runoff Depth=2.95" Tc=11.1 min CN=82 17.44 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 4HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 251S: GW5 Runoff = 66.81 cfs @ 12.05 hrs, Volume= 4.177 af, Depth= 3.23" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 100 Year Rainfall=4.85" Area (ac) CN Description * 15.520 85 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.7 Direct Entry, Workbook- Lag Subcatchment 251S: GW5 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Type II 24-hr 100 Year Rainfall=4.85" Runoff Area=15.520 ac Runoff Volume=4.177 af Runoff Depth=3.23" Tc=13.7 min CN=85 66.81 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 5HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 263S: GW4 Runoff = 39.83 cfs @ 12.00 hrs, Volume= 2.128 af, Depth= 3.53" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Type II 24-hr 100 Year Rainfall=4.85" Area (ac) CN Description * 7.240 88 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.5 Direct Entry, Workbook- Lag Subcatchment 263S: GW4 Runoff Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type II 24-hr 100 Year Rainfall=4.85" Runoff Area=7.240 ac Runoff Volume=2.128 af Runoff Depth=3.53" Tc=8.5 min CN=88 39.83 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 6HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 250P: GravelWet4 Inflow Area = 7.240 ac, Inflow Depth = 3.53" for 100 Year event Inflow = 39.83 cfs @ 12.00 hrs, Volume= 2.128 af Outflow = 21.63 cfs @ 12.10 hrs, Volume= 2.128 af, Atten= 46%, Lag= 5.9 min Primary = 21.63 cfs @ 12.10 hrs, Volume= 2.128 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 377.67' Surf.Area= 11,136 sf Storage= 5,379 cf Peak Elev= 381.83' @ 12.10 hrs Surf.Area= 23,814 sf Storage= 41,880 cf (36,502 cf above start) Plug-Flow detention time= 343.4 min calculated for 2.004 af (94% of inflow) Center-of-Mass det. time= 283.3 min ( 1,081.5 - 798.2 ) Volume Invert Avail.Storage Storage Description #1 375.00' 5,189 cf Custom Stage Data (Prismatic) Listed below (Recalc) 12,973 cf Overall x 40.0% Voids #2 377.33' 373 cf Custom Stage Data (Prismatic) Listed below (Recalc) 3,731 cf Overall x 10.0% Voids #3 378.00' 38,456 cf Custom Stage Data (Prismatic) Listed below (Recalc) 44,018 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 375.00 5,568 0 0 377.33 5,568 12,973 12,973 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 377.33 5,568 0 0 378.00 5,568 3,731 3,731 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 378.00 5,568 0 0 379.00 8,177 6,873 6,873 380.00 9,713 8,945 15,818 381.00 11,305 10,509 26,327 382.00 12,953 12,129 38,456 Device Routing Invert Outlet Devices #1 Primary 377.67'18.0" Round Culvert L= 15.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 377.67' / 376.00' S= 0.1113 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 377.67'2.5" Vert. Orifice/Grate C= 0.600 #3 Device 1 379.00'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 380.10'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 381.25'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 7HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=21.60 cfs @ 12.10 hrs HW=381.83' (Free Discharge) 1=Culvert (Passes 12.09 cfs of 12.41 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.33 cfs @ 9.70 fps) 3=Orifice/Grate (Orifice Controls 0.04 cfs @ 8.04 fps) 4=Orifice/Grate (Orifice Controls 11.71 cfs @ 5.86 fps) 5=Broad-Crested Rectangular Weir (Weir Controls 9.52 cfs @ 2.04 fps) Pond 250P: GravelWet4 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=7.240 ac Peak Elev=381.83' Storage=41,880 cf 39.83 cfs 21.63 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 8HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Pond 252P: GravelWet5 Inflow Area = 15.520 ac, Inflow Depth = 3.23" for 100 Year event Inflow = 66.81 cfs @ 12.05 hrs, Volume= 4.177 af Outflow = 45.19 cfs @ 12.16 hrs, Volume= 4.177 af, Atten= 32%, Lag= 6.3 min Primary = 45.19 cfs @ 12.16 hrs, Volume= 4.177 af Routing by Stor-Ind method, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Starting Elev= 364.67' Surf.Area= 17,280 sf Storage= 8,346 cf Peak Elev= 369.33' @ 12.16 hrs Surf.Area= 35,164 sf Storage= 69,952 cf (61,606 cf above start) Plug-Flow detention time= 366.7 min calculated for 3.985 af (95% of inflow) Center-of-Mass det. time= 318.0 min ( 1,130.8 - 812.8 ) Volume Invert Avail.Storage Storage Description #1 362.00' 8,052 cf Custom Stage Data (Prismatic) Listed below (Recalc) 20,131 cf Overall x 40.0% Voids #2 364.33' 579 cf Custom Stage Data (Prismatic) Listed below (Recalc) 5,789 cf Overall x 10.0% Voids #3 365.00' 64,384 cf Custom Stage Data (Prismatic) Listed below (Recalc) 73,015 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 362.00 8,640 0 0 364.33 8,640 20,131 20,131 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 364.33 8,640 0 0 365.00 8,640 5,789 5,789 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 365.00 8,640 0 0 366.00 12,649 10,645 10,645 367.00 14,154 13,402 24,046 368.00 15,717 14,936 38,982 369.00 17,336 16,527 55,508 369.50 18,166 8,876 64,384 Device Routing Invert Outlet Devices #1 Primary 364.67'18.0" Round Culvert L= 37.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 364.67' / 358.00' S= 0.1803 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 364.67'2.8" Vert. Orifice/Grate C= 0.600 #3 Device 1 365.85'1.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 367.50'48.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #5 Primary 368.00'8.0' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 9HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=45.17 cfs @ 12.16 hrs HW=369.33' (Free Discharge) 1=Culvert (Passes 12.58 cfs of 13.28 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.44 cfs @ 10.26 fps) 3=Orifice/Grate (Orifice Controls 0.05 cfs @ 8.93 fps) 4=Orifice/Grate (Orifice Controls 12.09 cfs @ 6.05 fps) 5=Broad-Crested Rectangular Weir (Weir Controls 32.59 cfs @ 3.06 fps) Pond 252P: GravelWet5 InflowPrimary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Inflow Area=15.520 ac Peak Elev=369.33' Storage=69,952 cf 66.81 cfs 45.19 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 10HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 246L: Sn006 Inflow Area = 11.270 ac, Inflow Depth = 3.32" for 100 Year event Inflow = 36.77 cfs @ 12.07 hrs, Volume= 3.117 af Primary = 36.77 cfs @ 12.07 hrs, Volume= 3.117 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Link 246L: Sn006 Inflow Primary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=11.270 ac 36.77 cfs36.77 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2023-post Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 11HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 247L: Sn007 Inflow Area = 15.520 ac, Inflow Depth = 3.23" for 100 Year event Inflow = 45.19 cfs @ 12.16 hrs, Volume= 4.177 af Primary = 45.19 cfs @ 12.16 hrs, Volume= 4.177 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-128.00 hrs, dt= 0.01 hrs Link 247L: Sn007 Inflow Primary Hydrograph Time (hours) 12512011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 1412 10 8 6 4 2 0 Inflow Area=15.520 ac 45.19 cfs45.19 cfs 18S GW4-Pre 19S GW5-Pre 19L SN6 20L SN7 Routing Diagram for Eastview2022-prePrepared by Krebs & Lansing Consulting Engineers, Inc., Printed 7/8/2024 HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Subcat Reach Pond Link Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 2HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Project Notes Eastview Pre Development Stormwater Model Qp10 & Qp100 Type II 24-hr 10 Year Rainfall=3.25"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 3HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 18S: GW4-Pre Area to 24" Culvert on Kennedy Drive east of Windridge Runoff = 20.51 cfs @ 12.04 hrs, Volume= 1.212 af, Depth= 1.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 Year Rainfall=3.25" Area (ac) CN Description * 11.100 78 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Workbook-Lag Subcatchment 18S: GW4-Pre Runoff Hydrograph Time (hours)48474645444342414039383736353433323130292827262524232221201918171615141312111098765 Fl o w ( c f s ) 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 10 Year Rainfall=3.25" Runoff Area=11.100 ac Runoff Volume=1.212 af Runoff Depth=1.31" Tc=12.0 min CN=78 20.51 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 4HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 19S: GW5-Pre Area to 24" Culvert on Kennedy Drive east of Windridge Runoff = 23.99 cfs @ 12.10 hrs, Volume= 1.694 af, Depth= 1.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 Year Rainfall=3.25" Area (ac) CN Description * 15.520 78 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.3 Direct Entry, Workbook-Lag Subcatchment 19S: GW5-Pre Runoff Hydrograph Time (hours)48474645444342414039383736353433323130292827262524232221201918171615141312111098765 Fl o w ( c f s ) 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type II 24-hr 10 Year Rainfall=3.25" Runoff Area=15.520 ac Runoff Volume=1.694 af Runoff Depth=1.31" Tc=17.3 min CN=78 23.99 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 5HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 19L: SN6 Inflow Area = 11.100 ac, Inflow Depth = 1.31" for 10 Year event Inflow = 20.51 cfs @ 12.04 hrs, Volume= 1.212 af Primary = 20.51 cfs @ 12.04 hrs, Volume= 1.212 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Link 19L: SN6 Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086 Fl o w ( c f s ) 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=11.100 ac 20.51 cfs20.51 cfs Type II 24-hr 10 Year Rainfall=3.25"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 6HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 20L: SN7 Inflow Area = 15.520 ac, Inflow Depth = 1.31" for 10 Year event Inflow = 23.99 cfs @ 12.10 hrs, Volume= 1.694 af Primary = 23.99 cfs @ 12.10 hrs, Volume= 1.694 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Link 20L: SN7 Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086 Fl o w ( c f s ) 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=15.520 ac 23.99 cfs23.99 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 7HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 18S: GW4-Pre Area to 24" Culvert on Kennedy Drive east of Windridge Runoff = 40.72 cfs @ 12.04 hrs, Volume= 2.391 af, Depth= 2.58" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 Year Rainfall=4.85" Area (ac) CN Description * 11.100 78 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Workbook-Lag Subcatchment 18S: GW4-Pre Runoff Hydrograph Time (hours)48474645444342414039383736353433323130292827262524232221201918171615141312111098765 Fl o w ( c f s ) 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type II 24-hr 100 Year Rainfall=4.85" Runoff Area=11.100 ac Runoff Volume=2.391 af Runoff Depth=2.58" Tc=12.0 min CN=78 40.72 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 8HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Subcatchment 19S: GW5-Pre Area to 24" Culvert on Kennedy Drive east of Windridge Runoff = 48.07 cfs @ 12.10 hrs, Volume= 3.343 af, Depth= 2.58" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 Year Rainfall=4.85" Area (ac) CN Description * 15.520 78 Workbook Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.3 Direct Entry, Workbook-Lag Subcatchment 19S: GW5-Pre Runoff Hydrograph Time (hours)48474645444342414039383736353433323130292827262524232221201918171615141312111098765 Fl o w ( c f s ) 50 45 40 35 30 25 20 15 10 5 0 Type II 24-hr 100 Year Rainfall=4.85" Runoff Area=15.520 ac Runoff Volume=3.343 af Runoff Depth=2.58" Tc=17.3 min CN=78 48.07 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 9HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 19L: SN6 Inflow Area = 11.100 ac, Inflow Depth = 2.58" for 100 Year event Inflow = 40.72 cfs @ 12.04 hrs, Volume= 2.391 af Primary = 40.72 cfs @ 12.04 hrs, Volume= 2.391 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Link 19L: SN6 Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086 Fl o w ( c f s ) 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=11.100 ac 40.72 cfs40.72 cfs Type II 24-hr 100 Year Rainfall=4.85"Eastview2022-pre Printed 7/8/2024Prepared by Krebs & Lansing Consulting Engineers, Inc. Page 10HydroCAD® 10.00 s/n 06429 © 2013 HydroCAD Software Solutions LLC Summary for Link 20L: SN7 Inflow Area = 15.520 ac, Inflow Depth = 2.58" for 100 Year event Inflow = 48.07 cfs @ 12.10 hrs, Volume= 3.343 af Primary = 48.07 cfs @ 12.10 hrs, Volume= 3.343 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Link 20L: SN7 Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086 Fl o w ( c f s ) 50 45 40 35 30 25 20 15 10 5 0 Inflow Area=15.520 ac 48.07 cfs48.07 cfs