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HomeMy WebLinkAbout20171559 Ver 3_More Info Received_20211116Homewood, Sue From: Miller, Vickie M. (Raleigh) <Vickie.Miller@hdrinc.com> Sent: Tuesday, November 16, 2021 10:17 PM To: Homewood, Sue; Wendee Smith; Jim Melvin Cc: Masemore, Sushma; Wojoski, Paul A; Smith, Danny; Gibby, Jean B CIV USARMY CESAW (USA); Mcdaniel, Chonticha; Anna Moore Subject: [External] RE: GRMS Request for Additional Information Follow Up Flag: Follow up Flag Status: Completed CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to Report Spam. Hi Sue, As noted on November 10th, we are providing responses as they are finalized. You should receive a OneDrive link to the updated stormwater plan and comment responses for your review. This submittal addresses Items 9 to 23 of the items requested on November 5, 2021. To date responses have been provided for items 9-23 and 26-31. Please let us know if you have additional questions related to the stormwater management plan category of comments. Also, if anyone has issues accessing OneDrive then please let me know as soon as possible. Everyone should have access but I want to make certain there isn't an issue. Thank you, Vickie Vickie Miller, AICP, Pws D 919.232.6637 M 919.559.2632 hdrinc.com/follow-us 1 hdrinc.com November 16, 2021 U.S. Army Corps of Engineers Raleigh Regulatory Field Office 3331 Heritage Trade Drive, Suite 105 Wake Forest, NC 27587 North Carolina Department of Environmental Quality 217 West Jones Street Raleigh, NC 27603 ATTN: Ms. Sue Homewood and Ms. Jean Gibby SUBJECT: Individual Permit Application Additional Information Request Greensboro Randolph Megasite and Associated Infrastructure Randolph County, North Carolina Ms. Homewood and Ms. Gibby: The Greensboro -Randolph Megasite Foundation, Inc. (GRMF) is providing the following additional information requested by the DWR regarding the individual permit application for development of the proposed Greensboro -Randolph Megasite, located in northern Randolph County, North Carolina. Below you will find responses to comments received on November 5, 2021 from DWR regarding the stormwater plan (Comments 9-23). The stormwater plan is attached for review. This is a partial response to the comments received on November 5, 2021 and additional information is forthcoming on the remaining comments. COMMENT 9 — Based on your October 27th response, explain what is meant by "The SCMs located internal to the pad use areas that cannot be avoided but can be for temporary storage of Stormwater." If the stormwater SCMs were located off the pad, what specifically makes the pad impact necessary. RESPONSE — The manufacturing building pads include a set number of buildings located on relatively flat areas and arranged in a manner required for the manufacturing process. The building layout shown on the overall grading plan was optimized to satisfy the required number of buildings and layout at acceptable grades. The rail yard located on the east side of the property also needs to be relatively flat and the location is set by acceptable rail radius and ability to store a set number of rail cars. The storage area adjacent to the rail yard is set by the buildings located in the northeast portion of the site and the size is set by the manufacturing facility required storage area. The SCMs are located between these 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034 (919) 232-6600 set building and storage area locations, therefore removing these SCMs would not change the pad layout. COMMENT 10 — In the justification for dry attenuation basins provided on October 27, it was stated that dry ponds were selected "to take advantage of the available site area internal to the pad". Why is there available site area in the pad if it has been minimized to the maximum extent and why does removing dry attenuation basin from the pad "not significantly reduce the size of the pad"? RESPONSE — As noted in the response above, the manufacturing building pads, storage area and rail yard are set to accommodate the manufacturing process and storage requirements, as well as design elements (ie. turning radius, setbacks, etc.) These locations were optimized. The dry attenuation basins were located between these set locations in areas that would otherwise be grass or landscaped. Therefore, removing these would not change the site configuration. COMMENT 11—Based on the information provided in the most recent site plan and conceptual stormwater management plan, all surface flow from the project is proposed to be rerouted through three wet detention basins. The outlets from the wet basins are proposed to be located as indicated on the conceptual stormwater management plan. The rerouting of the drainage area and surface flow from the site through these three stormwater basins has the potential to remove existing hydrology within multiple water of the state and therefore remove existing uses within the stream channels and wetlands. Specifically, the Division notes that according to the information available on the most recent site plan and stormwater management plan and the stream identifiers as noted on the jurisdictional determination map submitted on October 15, 2021: • COMMENT — The entire watershed draining to stream S45 will be redirected to Wet Pond A3. The outlet of Wet Pond A3 discharges to stream SN. The portion of stream S45 below the impact limits to the confluence of SE (as shown on the maps below) will experience significant indirect impacts from the loss of hydrology to the channel. RESPONSE — Wet Pond A3 was relocated to be positioned upstream of S45 and closer to the proposed Al and A2 drainage areas. The wet pond will be located outside the pad area and discharge to a tributary to S45 which confluences with S45 approximately 150 feet downstream of the pad. Currently the stream impacts are shown to extend approximately 750 feet downstream of the pad. In addition to the outlet of Wet Pond A3, the proposed main underdrains have been added to the overall grading plan. These underdrains will be installed in the existing stream channel and are shown to the cut/fill extent. In the cut areas, underdrains will be added as required to control groundwater. These additional underdrains will connect to the main underdrain. These underdrains will remain in place and provide continuous hydrology to the existing stream. • COMMENT —The entire watershed draining to stream S1 and HDR WA will be redirected to Wet Pond B2. The outlet of Wet Pond B2 discharges to a downstream location on Dodson Lake. The portion of stream S1 and wetland 2 HDR WA (as shown on the maps below) will experience significant indirect impacts from the loss of hydrology to the channel and wetland. RESPONSE — Wet Pond B2 was reconfigured so the outlet would discharge to stream S1. In addition to the outlet of Wet Pond B2, proposed main underdrains have been added to the overall grading plan. These underdrains will be installed in the existing stream channel and are shown to the cut/fill extent. In the cut areas, underdrains will be add as required to control groundwater. These additional underdrains will connect to the main underdrain. These underdrains will remain in place and provide continuous hydrology to the existing stream. • COMMENT —The majority of stream S18, S17, wetlands WW, W15, W17, W18B and W16 (shown on the maps below) will be redirected to either Wet Pond B2 or Wet Pond C2. The outlets of Wet Ponds B2 and C2 are located within different drainage areas. These streams and wetlands will experience significant indirect impacts from the loss of hydrology to the area. RESPONSE — The existing stream S17 was determined by the agencies to begin at the base of a 9-acre drainage area which indicates that 9 acres will support stream function in this area. Five hundred (500) feet of stream S17 were included in the site impacts and therefore the new anticipated headwater for the stream will be located 500 feet downstream where the proposed drainage area will be 15 acres which is greater than the existing stream headwater drainage area of 9 acres. The drainage area to S18 will be reduced from 18 acres to 9 acres. Since 9 acres was sufficient to support the existing stream S17 this should be sufficient to support S18. In addition, proposed main underdrains were added to the overall stormwater grading plan. These underdrains will be installed in the existing stream channel and will remain in place and provide additional hydrology to stream S17 and S18. COMMENT 12— You have provided a stormwater management plan that indicates that the proposed Wet Pond A3 will be constructed within a natural drainage way where Pond P17 currently exists and P16 and W3 are upslope of this area. The Division has the following concerns regarding this design: A detailed analysis must be provided to document that impacts to jurisdictional features has been avoided and minimized throughout the project, including impacts beyond the footprint of the "site". This should include a detailed analysis of any possible upland locations for stormwater treatment and any possible alternative stormwater treatment control measures which would avoid impacts to jurisdictional features. Possible alternatives may be multiple wet ponds on either side of the jurisdictional feature or alternative stormwater control measures that provide smaller land requirements such as bioretention basins or sand filters. If sufficient justification is provided to support the proposed Wet Pond A3, the Divisions has concerns regarding the directing existing hydrology and/or flow through a stormwater control measure. Provide further details about how existing hydrology will be rerouted .so that it does not impact the long term function of Wet Pond A3. 3 RESPONSE — The reason Wet Pond A3 was located initially at the location of the existing pond is because this was shown as being part of the site impacts. Based on this comment as well as comment 11, Wet Pond A3 has been relocated to the northeast portion of the site adjacent to the site pad. This site plan modification was made in direct response to DWR's concerns. With this modification all concerns expressed within DWR's comment 12 should be alleviated. COMMENT 13 — The offsite drainage area in area C will be bypassed, how much volume will be bypassed? Where will this bypass be discharged? Note that if this bypass is going to be discharged into one of the three proposed outfalls, it should also be accounted for in the design and flow calculations. RESPONSE — Approximately 151 acres of the existing drainage area C, identified as C2.U, located to the east of the proposed site pad will be relocated around the pad in a channel that runs along the east side of the pad and discharges near the toe of pad where the existing stream is located. This channel is shown on the overall site grading plan. This area is undeveloped with an average runoff curve number of 74.5 which means that on an average rainfall year of 46-inches approximately 530 acre-feet of water will be bypassed around the pad. An additional 193 acres, identified as C3.0 drains below the pad directly to outfall C. These offsite areas were included in the outfall C peak discharge calculations. COMMENT 14 — Dry ponds Al and A2 are being proposed at possibly 4-29 feet below the existing groundwater elevation. In addition, the plan states that "groundwater will be diverted around the pads and it is anticipated the future groundwater will be below the dry ponds". This raises concern over how the groundwater lowering and control at the site will be accomplished since this is a very complex and difficult task with no actual plan being provided. In addition, the amount of groundwater that need to be diverted and the destination of groundwater discharge are unknown. This groundwater issue can significantly impact the stormwater wet pond capacity, discharging outfalls, and water quality standards (for both groundwater and surface waters). RESPONSE — Dry Ponds Al and A2 have been removed and it is proposed to drain the site pad areas Al and A2 to the relocated Wet Pond A3. Dry ponds B1 and Cl are located within fill areas so groundwater will be below these ponds. The overall groundwater strategy is to install groundwater drains in the natural stream channel to the cut/fill extent. In the cut areas, groundwater drains will be installed during construction and discharge to the natural stream channel. In areas of fill, a groundwater drain will be installed in the natural stream channel prior placing fill. The groundwater drains in the cut areas will be connected to the groundwater drains in the natural stream channels maintaining the groundwater discharge to the stream below the site pad. The main groundwater drains in the natural stream channels have been shown on the overall stormwater grading plan to the proposed cut/fill extent. COMMENT 15 — The plan states "the peak discharge for all three outfalls were reduced compared to the existing condition". However, at outfall A, it appears that the proposed 10- year peak discharge is higher than the pre/existing peak discharge (373 cfs vs 345 cfs). See tables 3 and 5 of the SMP report. Please review these numbers/calculations and explain. 4 RESPONSE — Additional outfall points were added to the existing drainage areas A and B to better reflect the proposed discharges prior to entering Dodson Lake. Figure 1 in the Stormwater Management Plan (SMP) report was updated to show these additional outfall locations. Pond A3 was relocated and revised to include the water quality treatment as well a peak discharge attenuation. Table 5 was modified to include the two additional outfall locations and the existing condition peak discharge to demonstrate the proposed discharges are less than the existing discharges. COMMENT 16 — There are several undisturbed areas identified on the plan with no impervious surfaces being proposed. If these lands are to be developed in the future, will a separate stormwater control measure be provided? Note that the currently proposed wet ponds and discharges at outfall do not account for future uses of these areas. RESPONSE — These areas are intended to remain undeveloped and is part of the buffer between the manufacturing facility and the surrounding properties. However, should future development be planned in these areas, separate SCMs will be required and coordinated with DWR. COMMENT 17 — On the site plan, there is an unknown basin marked as "not use" (at the NE corner of the site), please clarify. RESPONSE — This was an area originally identified for a dry pond, however, this area was not required and therefore not reflected in the SMP. The site plan has been updated to be consistent with the updated SMP. COMMENT 18 — In the design calculations for wet ponds, the numbers for pond bottom elevation and sediment storage elevations switched places, please check and revise as needed. RESPONSE — This elevation is intended to reference the bottom of the sediment storage and the pond bottom is the top of the sediment storage. The table was modified to say "Bottom of Sediment Storage Elevation". The sediment storage is not included in the calculations. COMMENT 19 — On the wet Pond C2 drawing, the sediment storage elevation should be at 644 (not 643), please check and revise as needed. RESPONSE — The elevation 643 was intended to reference the bottom of the sediment storage and the pond bottom is the top of the sediment storage. The table was modified to say "Bottom of Sediment Storage Elevation". The sediment storage is not included in the calculations. COMMENT 20 — Scour hole calculations for pond B and C are incomplete for the flow calculation at the lower bottom of each page. RESPONSE — The calculations at the lower bottom of the page are for projects that also include proposed downstream channelization. The outfalls for each of these ponds will be discharging to existing streams and therefore no downstream channelization will be required. Therefore, these calculations were removed from the scour hole calculations. 5 COMMENT 21 — Please explain why the forebay design of ponds B2 and C2 are greater than 20% of its pool volume. Please note that the stormwater Minimum Design Criteria specifies the designed range to be exactly between 155-20%. RESPONSE — The sediment forebays have been adjusted to remain within the 15%-20% range. COMMENT 22 — Please note that the proposed 100-year peak discharges number provided in Table 5 do not match the numbers presented in the HydroCAD Model. Please review and revise as needed. RESPONSE — These numbers have been modified and match the HydroCAD Model. Please note that two (2) additional outfall locations were added to the tables as noted in our response to Comment 15. COMMENT 23 — Provide an overall plan sheet with proposed grading/topography shows the entire property, all streams, wetlands and open waters and all SCMs and drainage network. RESPONSE —The overall site plan sheet was provided in Appendix E. This sheet has been updated to reflect the items described in the responses above. This sheet shows all of the streams, wetlands, open waters and SCMs. The sheet does not show the internal site drainage network as the detail site design has not been performed at this time. The site plan does show the storm drainage system from the pad to the wet ponds. The Applicant looks forward to working with the DWR on completing the permitting process and issuance of a 401 Water Quality Certification for the GRMS project. Please call me at 919-232-6637 or email at vickie.miller@hdrinc.com if you need additional information or clarification on any of the information provided Sincerely, HDR Engineering Inc. of the Carolinas Vrku� rftll�� Vickie Miller, AICP, PWS Senior Environmental Planner cc: Jim Melvin, Greensboro Randolph Megasite Foundation Wendee Smith, S2 Consulting Attachment: Stormwater Management Plan 6 FN STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Randolph County, North Carolina November 15, 2021 F�2 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Randolph County North Carolina November 15, 2021 °'4a�gx aa 4 ry O O`�gy:' c * RpD q�, f''.+ ^' Iry STORMWATER MANAGEMENT PLAN F)� GREENSBORO-RANDOLPH MEAGASITE Table of Contents 1 Introduction 1 2 Site Description 1 3 Project Description 1 4 Stormwater Management Plan 1 4.1 Design Requirements 2 4.2 Existing Conditions Model 2 4.2.1 Outfall Locations and Drainage Areas 2 4.2.2 Runoff Curve Numbers and Time of Concentration 3 4.2.3 Rainfall 3 4.2.4 Existing Peak Discharges 3 4.3 Proposed Stormwater Control Measures 4 4.3.1 Proposed Hydrologic Parameters 4 4.3.2 Proposed Dry Detention Basins 5 4.3.3 Proposed Wet Ponds 6 4.4 Proposed Conditions Model Results 7 4.5 Conclusion 7 5 References 8 Tables Table 1. Summary of RCN and Tc 3 Table 2. 24-hour Total Rainfall 3 Table 3. Existing Peak Discharges 4 Table 4. Summary of Proposed RCN and Tc 5 Table 5. Proposed Peak Discharges 7 Appendices Appendix A — Figures Appendix B - NOAA Atlas 14 Rainfall Depths Appendix C — Existing Condition Model Results Appendix D — Proposed Weighted RCN Calculations Appendix E — Proposed Ponds Calculations and Grading Appendix F — Proposed Conditions Model Results November 15, 2021 I i STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE 1 Introduction The Greensboro -Randolph Megasite (GRMS) is a large tract of land located in Randolph County, North Carolina that can support large-scale manufacturing facilities. Currently, there are plans to construct approximately 1000 acres of manufacturing and distribution facilities. The purpose of this document is to summarize how the stormwater will be managed to meet the State of North Carolina requirements as well as provide additional controls to manage the larger flood events to reduce risk of increased downstream flooding. 2 Site Description The roughly 1,800-acre site is in the northeast portion of Randolph County between US 421 and Old 421 Road near the county line as shown on Figure 1 in Appendix A. Old 421 Road bounds the northern property boundary and is also the natural ridge, so all of the property drains in southerly direction towards Dodson Lake and Sandy Creek. Dodson Lake stream and Dodson Lake is located along the southern boundary of the site and confluences with Sandy Creek just southeast of the property. There are two (2) main tributaries on the site that drain into Dodson Lake and one (1) main tributary on the site that drains into Sandy Creek. Dodson Lake stream and portions of Dodson Lake Tributary 1 and Sandy Creek Tributary 7 have limited detailed studied (LDS) special flood hazard areas (SFHAs) The site consists mainly of farm and pasture lands with some forested areas in the southern and eastern portion of the site. There are several small farm ponds within the project area. 3 Project Description The overall project is the construction of a manufacturing facility that covers approximately 1,000 acres. The facility includes multiple office, manufacturing, and storage buildings along with employee parking, truck access, rail yard, and other ancillary facilities that support the manufacturing process. The manufacturing facility requires large level areas for efficient processes and therefore the site will require significant areas of cut and fill to create a few level pads at different elevations to reduce the necessary earthwork. A significant portion of the site will be impervious surfaces and the remaining areas will likely be grass and landscape areas. 4 Stormwater Management Plan The overall stormwater management plan for the GRMS includes a combination of dry attenuation basins located on the level pads and water quality ponds located near the toe of the pads to control stormwater runoff and comply with the North Carolina post construction stormwater requirements. The built upon site area will drain to the dry November 15, 2021 11 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE attenuation basins which will reduce the peak discharges to existing levels and the water quality ponds will provide treatment of the stormwater runoff from the built upon area prior to the identified outfalls which are just upstream of Dodson Lake and where Sandy Creek Tributary 7 leaves the site. This section summarizes the stormwater management requirements, describes how the existing peak discharges were determined at the identified outfall locations, presents each of the proposed dry attenuation basins and water quality ponds and summarizes the results of the hydrologic and hydraulic model. 4.1 Design Requirements The State of North Carolina Department of Environmental Quality (NCDEQ) Division of Energy, Mineral, and Land Resources (DEMLR) Stormwater Program oversees compliance of the stormwater runoff regulations. The regulations vary across the state depending on the watershed. The GRMS is located within a Watershed III Basin and is a high -density project requiring compliance with the post construction stormwater regulations that meet 15A NCAC 02H .1020 Universal Stormwater Management Program which includes: • Runoff treatment of the built upon area through a primary stormwater control measure (SCM) as identified in the NCDEQ Stormwater Design Manual. o The wet pond is a primary SCM. • Demonstration that the 10-year peak discharge from the site will not increase downstream erosion. o By attenuating the proposed 10-year peak discharge to the existing condition level, the stormwater outlets will not cause erosion downslope of the discharge point over current levels. In addition to the NCDEQ post construction regulations, the GRMS SCMs were also designed to not increase the existing 100-year peak discharge. This additional attenuation is being performed to reduce the risk of increased downstream flooding and supports the removal of existing SFHA areas on the project site. 4.2 Existing Conditions Model The existing peak discharges were developed using the HydroCAD computer model which generates stormwater hydrographs for defined areas and routes and combines these hydrographs at specified locations. For this project the stormwater hydrographs were generated using the National Resource Conservation Service (NRCS) runoff curve number method (RCN) method along with the NOAA Atlas 14 center weighted storm distribution for the different storm frequency events. 4 2.1 Outfall Locations and Drainage Areas Five (5) outfalls were identified and referred to as A-1, A-2, B-1, B-2 and C. Outfall A-1, A-2, B-1, and B-2 are located just upstream of Dodson Lake and outfall C is located on Sandy Creek Tributary 7 just upstream of where the tributary leaves the project site. These outfall locations are shown on Figure 1 in Appendix A. 2 I November 15, 2021 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE 4.2.2 Runoff Curve Numbers and Time of Concentration A weighted RCN was determined for each drainage area based on the landuse and soil type. The landuse and soils are shown in Figures 2 and 3 in Appendix A. The time of concentration (Tc) represent the longest travel time of stormwater runoff in a drainage area. The NRCS Tc method identifies three (3) different travel paths, sheet flow, shallow concentrated, and channel flow. The travel time for each of these paths are summed up to determine the Tc. A summary of the RCN and Tc for each of the drainage areas are shown in Table 1 below. Table 1. Summary of RCN and Tc Drainage Area Area (Ac) RCN Tc (min) Al 235 78 63 A2 51 78 B1 440 77 83 B2 81 77 Cl 740 77 103 1.2.3 Rainfall The point frequency rainfall data was obtained from NOAA Atlas 14 for the 1-, 10-, 25-, 50-, and 100-year annual frequency events. For the stormwater management plan the 24-hour duration event was used to demonstrate compliance. A summary of the total rainfall amounts is shown in Table 2 below and a copy of the NOAA Atlas 14 is provided in Appendix B. Table 2. 24-hour Total Rainfall Annual Frequency Depth (in) 1-Year 2.89 10-Year 25-Year 5.95 50-Year 100-Year 7.42 The NRCS Curve B was used to distribute the rainfall across the 24-hour period. This distribution is based on the NOAA Atlas 14 recommended center weighted storm and introduces a smoothing factor depending on the location. The GRMS is in the curve B region. 4.2.4 Existing Peak Discharges The results of the existing conditions HydroCAD model are shown in Table 3 below. The HydroCAD model results are provided in Appendix C. November 15, 2021 13 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Table 3. Existing Peak Discharges Outfall Point 10-yr Peak Discharge (cfs) 100-yr Peak Discharge (cfs) A-1 308 544 A-2 121 B-1 464 832 B-2 145 680 1220 4.3 Proposed Stormwater Control Measures The proposed SCMs include two (2) dry detention basins located within the site pads and three (3) wet ponds located just off the site pads fill slope and upstream of the outfall locations. The proposed built upon area (BUA) in drainage areas A drains directly to the wet pond through a combination of onsite storm drainage pipes and swales. The proposed BUA in drainage areas B and C all drain to a dry detention basin through a combination of onsite storm drainage pipes and swales The SCMs in drainage area A and B were designed for all the area naturally draining to the facilities. The offsite area in drainage area C will be diverted around the site pad. Figure 4 in Appendix A shows the pond locations and the overall site grading and proposed storm piping from each stormwater facility is shown in Appendix E. This section describes how the proposed hydrologic parameters were developed and then describes each SCM in more detail. 4.3.1 Proposed Hydrologic Parameters The proposed GRMS consists of large flat pads that supports large scale manufacturing, storing and distribution activities. The proposed drainage areas are shown on Figure 4 in Appendix A. The BUA draining to either the wet pond or dry attenuation basins were broken up into impervious areas and grassed areas as shown in Figure 5 in Appendix A. Weighted RCNs were calculated with the assumption that the grassed areas would be on D type soil which produces the most runoff. It was assumed that all BUA draining to either the wet pond or dry attenuation basins would be directly connected to the storm drainage system and no adjustment was made to the curve number based on disconnected impervious surfaces. The natural undisturbed areas that drain either to the wet ponds or directly to outfall A-1, A-2, B-1, B-2, and C were identified with a "U" as shown in Figure 4 in Appendix A. The weighted RCNs for these areas were calculated using the existing condition landuse and soil types. The proposed RCN calculations were provided in Appendix D. The proposed time of concentration (Tc) were estimated for the BUA assuming sheet flow of 10 minutes and quick travel times through storm pipes and channels to the wet 4 I November 15, 2021 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE pond or dry attenuation basins. A summary of the RCN and Tc for each of the drainage areas are shown in below. Table 4. Summary of Proposed RCN and Tc Drainage Area Area (Ac) RCN Tc (min) Al 99 94 20 A2 125 951 A3.0 54 76 30 37 781 .22 B1 279 95 30 34 737 IIP B3.0 62 69 30 Cl 534 91 30 C2.0 183 75 50 C3.0 162 72 45 4.3.2 Proposed Dry Detention Basins The dry detention basins were only designed to provide peak flow attenuation. These basins do not include extended detention for the water quality volume and do not include the water quality features identified in the NCDEQ Stormwater Design Manual. These facilities are designed to drain quickly and discharge to a primary SCM for water quality treatment. The outlet structures for the dry detention basins include an outlet pipe sized to attenuate the larger storm peak discharges. The outlet storm pipe systems will discharge directly to the wet pond sediment forebays which will dissipate the energy. The proposed grading of each of the dry detention basins are shown in Appendix E. Below is a brief description of each of the proposed dry detention basins. Pond B1 Dry Detention Basin Pond B1 is a dry detention basing that will have a ponded surface area of approximately 8.1 acres and a maximum depth of 10.0 feet during the 100-year rainfall event. The outlet structure is an 84-inch barrel that will discharge to the Pond B2 — Wet Pond sediment forebay. The pond captures 279 acres of the site. The pond bottom is at elevation 676 which is approximately 30 feet above the existing grade at the lowest portion of the pond and will above the existing groundwater elevation. Pond Cl — Dry Detention Basin Pond C1 is a dry detention basing that will have a ponded surface area of approximately 17 acres and a maximum depth of 17 feet during the 100-year rainfall event. The outlet is November 15, 2021 15 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE a 72-inch storm drainage pipe barrel that will discharge directly to the Pond C2 Wet Pond sediment forebay. The pond captures 534 acres of the site The pond bottom is at elevation 664 which is approximately 7 feet above the existing grade at the lowest portion of the pond and approximately 30 feet above the existing groundwater elevation. 4.3.3 Proposed Wet Ponds The proposed wet ponds were located outside the BUA and were designed to satisfy the primary SCM per the NCDEQ Stormwater Design Manual. The ponds were designed to have a normal pool with a maximum depth of 6 feet and average depth between 4.5 and 5.0 feet and a surface area greater than the SA/DA ratio and volume greater than the water quality volume. The sediment forebays were sized to be between 15 and 20% of the normal pool volume. The riser structures were sized to temporarily store the water quality volume and release this volume over a 4-to-5-day period. Preformed scour basins were sized for the wet pond outlet protection. These scour holes in addition to the peak flow attenuation will prevent additional downstream erosion. In addition to the water quality The wet pond sizing calculations, scour basin sizes and pond grading are shown in Appendix E. Pond Al — Wet Pond Pond Al will provide WQ volume for 278.5 acres of the site and will have a permeant pool surface area of approximately 3.9 acres. The maximum pool depth is 6 feet, and the average pool depth is 4.8 feet. The wet pond also provides the peak flow attenuation for drainage area A. This pond is controlled by 10 feet x 10 feet riser that extends 10 feet above the normal pool elevation. There is a 6-inch orifice at the normal pool elevation of 678 and a 54-inch orifice at elevation 681. The 6-inch orifice ponds up the water quality volume and slowly discharges it over a 4-day period. The 54-inch orifice attenuates the 10-year peak discharge. The riser discharges to a 60-inch outlet barrel which attenuates the 100-year peak discharge. The top of dam is set at elevation 692 which provides over 1 foot of freeboard during the 100-year event. Pond B2 — Wet Pond Pond B2 will provide WQ volume for 279 acres of the site and will have a permanent pool surface area of approximately 4.9 acres. The normal pool maximum depth is 6 feet and the average pool depth is 5.3 This pond is controlled by a 10 feet x 10 feet riser that extends 3 feet above the normal pool elevation. There is a 7-inch orifice at the normal pool elevation of 614 and the top of the riser is at elevation 617. The 7-inch orifice ponds up the water quality volume and slowly discharges it over a 5-day period. The riser discharges to a 66-inch outlet barrel. The top of dam is set at elevation 622 which provides 1 foot of freeboard during the 100- year event. 6 I November 15, 2021 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Pond C2 — Wet Pond Pond C2 will provide WQ volume for 533.8 acres of the site and will have a permeant pool surface area of approximately 8.9 acres. The maximum normal pool depth is 6 feet, and the average pool depth is 4.6 feet. This pond is controlled by a 10 feet x 10 feet riser that extends 3 feet above the normal pool elevation. There is a 10-inch orifice at the normal pool elevation of 650 and the top of the riser is at elevation 653. The 10-inch orifice ponds up the water quality volume and slowly discharges it over a 4-day period. The riser discharges to a 72-inch outlet barrel. The top of dam is set at elevation 657.5 which provides just less than 1 foot of freeboard during the 100-year event. 4.4 Proposed Conditions Model Results A separate HydroCAD model was produced for the proposed conditions. The BUA was added to the dry detention basin ponds which then discharged to a wet pond. Since the wet ponds are located near the natural ridges, additional area was not added to the ponds. The undisturbed natural areas that don't drain to the ponds were added to the model to determine the proposed peak discharges at each outfall. The results of the proposed conditions HydroCAD model are shown in Table 5 below. 1 abbe 5. Proposed NeaK uiscnarges Duffel! Point 10-yr Peak Discharge (cfs) Existing Proposed 100-yr Peak Discharge (cfs) Existing Proposed A-1 308 278 544 530 A-2 121 88 -I A 154 B-1 464 347 832 416 B-2 145 89 259 T 177 680 512 1220 1144 These results show that the peak discharge for all three outfalls were reduced compared to the existing conditions presented in Table 3. The HydroCAD model results are presented in Appendix F. 4.5 Conclusion This stormwater management plan demonstrates that the dry detention basins and wet ponds reduce the proposed peak discharges to at or below the existing conditions peak discharges at the three (3) of the five (5) identified outfall locations. The other two (2) outfall locations proposed peak discharges are reduced because the BUA is diverted to the dry detention basins. The reduction in the 10-year peak discharge to below the existing condition peak discharge will prevent an increase in erosion downstream of the property. The reduction in the 100-year peak discharge to below existing condition peak discharge will reduce the risk of downstream flooding during the 100-year event and support the removal of some SFHAs on the project site. All the outflow from the dry detention basins will be discharged to wet ponds that are sized per the NCDEQ November 15, 2021 17 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Stormwater Design Manual to provide the required water quality treatment prior to being discharge off the site. Preformed scour basins were designed for each wet pond outlet to dissipate energy and discharge downstream with non -erosive velocities. 5 References HydroCAD version 10.00-25 2019, HydroCAD Software Solutions LLC Stormwater Design Manual January 1, 2017, updated on November 20, 2020 — North Carolina Division of Environmental Quality, Department of Energy, Mineral, and Land Resources Urban Hydrology for Small Watersheds — TR-55 June 1986 — United States Department of Agriculture, Natural Resource Conservation Service NOAA Atlas 14 Precipitation -Frequency Atlas of the United States — Volume 2 2006 — National Oceanic and Atmospheric Administration 8 I November 15, 2021 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Appendix A - Figures November 15, 2021 11 LEGEND Existing Flowpaths Existing Drainage Areas Site Boundary • Outfall Points Outfall A" Outfall A`- tfall B B2 Outfall B-2 Outfall C F�2 EXISTING DRAINAGE CONDITIONS GREENSBORO MEGASITE FIGURE 1 PATH: A:\GIS\PROJECTSY10000000_GRMS_UPDATE\7.2_VNP\MAP_DOCS\APRX\EXHIBITS.APRX - USER: LVANDERLIN - DATE: 11/10/2021 INITIAL STORMWATER MANAGEMENT PLAN ■ �i ■ LEGEND NLCD Landuse - Open Water Developed, Open Space - Developed, Low Intensity - Developed, Medium Intensity Pasture/Hay ▪ Developed, High Intensity Barren Land Deciduous Forest I 0 F�2 ▪ Evergreen Forest Mixed Forest ▪ Cutivated Crops Woody Wetlands ▪ Emergent Herbaceous Wetlands Im0.6 tift7wt ogri • Tin • • • • _ EXISTING LANDUSE GREENSBORO MEGASITE FIGURE 2 PATH:A:\GIS\PROJECTS,00000000_GRMS_UPDATE\7.2_VNP\MAP_DOCS\APRX\EXHIBITS.APRX - USER: LVANDERLIN - DATE: 10/15/2021 INITIAL STORMWATER MANAGEMENT PLAN LEGEND LJ Site Boundary Soil HSG Water A 1 B 0 Miles MaB keB2 WtC • WpE ChA F�2 MeB2 PaC B/D C C/D D WtC ApC WzB Wp ApC ApB MaD CmA CeB WtB WpC P PATH: A:\GIS\PROJECTSY10000000_GRMS_UPDATE\7.2_VNP\MAP_DOCS\APRX\EXHIBITS.APRX - USER: LVANDERLIN - DATE: 10/15/2021 CcC CcC WtB cC eB2 C CeB2 1 EXISTING SOILS GREENSBORO MEGASITE FIGURE 3 INITIAL STORMWATER MANAGEMENT PLAN O Outfall Points Proposed Drainage Areas Proposed Ponds Site Boundary Outfall Outfall F�2 PROPOSED DRAINAGE CONDITIONS GREENSBORO MEGASITE FIGURE 4 PATH:A:\GIS\PROJECTS \00000000_GRMS_UPDATE/7.2_VNP\MAP_DOCS\APRX\EXHIBITS.APRX - USER: LVANDERLIN - DATE: 11/11/2021 INITIAL STORMWATER MANAGEMENT PLAN Proposed Grass Proposed Impervious Site Boundary F�2 PATH:A:\GIS\PROJECTSY10000000_GRMS_UPDATE\].2_VNP\MAP_DOCS\APRX\EXHIBITS.APRX - USER: LVANDERLIN - DATE: 11/11/2021 PROPOSED SITE IMPERVIOUSNESS GREENSBORO MEGASITE FIGURE 5 INITIAL STORMWATER MANAGEMENT PLAN STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Appendix B — NOAA Atlas 14 Rainfall Depths 2 I November 15, 2021 11/1/2017 Precipitation Frequency Data Server NOAA Atlas 14, Volume 2, Version 3 Location name: Liberty, North Carolina, USA* Latitude: 35.89°, Longitude: -79.6222° Elevation: 666.1 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Durati n Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.398 0.472 0.549 0.600 0.656 0.691 0.722 0.746 0.770 0.786 (0.364-0.435) (0.433-0.517) (0.502-0.600) (0.549-0.655) (0.596-0.715) (0.626-0.754) (0.651-0.787) (0.670-0.815) (0.686-0.842) (0.693-0.859) 10-min 0.636 0.756 0.879 0.960 1.05 1.10 1.15 1.18 1.22 1.24 (0.582-0.695) (0.693-0.826) (0.805-0.961) (0.877-1.05) (0.950-1.14) (0.997-1.20) (1.03-1.25) (1.06-1.29) (1.08-1.33) (1.09-1.35) 15-min 0.795 0.950 1.11 1.21 1.33 1.39 1.45 1.49 1.53 1.55 (0.728-0.868) (0.871-1.04) (1.02-1.22) (1.11-1.32) (1.21-1.44) (1.26-1.52) (1.31-1.58) (1.34-1.63) (1.37-1.68) (1.37-1.70) 30-min 1.09 1.31 1.58 1.76 1.96 2.10 2.22 2.32 2.44 2.52 (0.998-1.19) (1.20-1.44) (1.45-1.73) (1.61-1.92) (1.78-2.14) (1.90-2.29) (2.00-2.42) (2.09-2.54) (2.17-2.67) (2.22-2.75) 60-min 1.36 (1.24-1.48) 1.65 (1.51-1.80) 2.03 (1.85-2.21) 2.29 (2.09-2.50) 2.61 (2.38-2.85) 2.84 (2.58-3.10) 3.06 (2.76-3.34) 3.26 (2.93-3.56) 3.50 (3.12-3.83) 3.67 (3.24-4.01) 2-hr 1.61 (1.48-1.76) 1.95 (1.79-2.13) 2.42 (2.22-2.65) 2.76 (2.52-3.01) 3.19 (2.90-3.48) 3.51 (3.17-3.82) 3.82 (3.43-4.16) 4.12 (3.67-4.49) 4.51 (3.97-4.91) 4.79 (4.18-5.22) 3-hr 1.72 (1.58-1.88) 2.09 (1.93-2.28) 2.60 (2.39-2.83) 2.97 (2.72-3.23) 3.46 (3.14-3.75) 3.62 (3.46-4.14) I 4.16 (3.76-4.52) 4.53 (4.04-4.91) 4.99 (4.40-5.41) 5.34 (4.66-5.80) 6-hr 2.09 (1.93-2.28) 2.53 (2.33-2.75) 3.14 (2.89-3.42) 3.61 (3.31-3.92) 4.23 (3.85-4.58) 4.71 (4.25-5.10) 5.20 (4.66-5.62) 5.69 (5.04-6.15) 6.35 (5.55-6.86) 6.86 (5.92-7.43) 12-hr 2.48 (2.29-2.71) 3.00 (2.76-3.28) 3.75 (3.44-4.09) 4.34 (3.97-4.72) 5.14 (4.66-5.58) 5.78 (5.20-6.25) 6.44 (5.74-6.96) 7.13 (6.28-7.69) 8.09 (6.99-8.72) 8.85 (7.53-9.55) 24-hr 2.90 (2.71-3.11) 3.50 (3.27-3.75) 4.37 (4.07-4.68) 5.04 (4.69-5.41) 5.96 (5.53-6.40) 6.69 (6.18-7.19) 7.43 (6.84-8.00) 8.20 (7.52-8.84) 9.25 (8.43-10.00) 10.1 (9.14-10.9) 2-day 3.39 (3.18-3.63) 4.08 (3.82-4.37) 5.05 (4.73-5.41) 5.79 (5.41-6.21) 6.79 (6.31-7.28) 7.57 (7.01-8.13) 8.36 (7.72-9.00) 9.17 (8.43-9.90) 10.3 (9.39-11.1) 11.1 (10.1-12.1) 3-day 3.59 4.31 5.32 6.10 7.15 7.98 8.82 9.68 10.9 11.8 (3.37-3.85) (4.04-4.62) (4.98-5.70) (5.70-6.53) (6.65-7.66) (7.40-8.56) (8.14-9.48) (8.90-10.4) (9.93-11.7) (10.7-12.8) 4-day 3.80 4.55 5.60 6.41 7.51 8.39 9.28 10.2 11.4 12.4 (3.56-4.06) (4.27-4.87) (5.24-5.98) (5.99-6.86) (7.00-8.04) (7.78-8.99) (8.57-9.96) (9.38-11.0) (10.5-12.4) (11.3-13.5) 7-day 4.35 5.18 6.29 7.17 8.36 9.30 10.3 11.3 12.6 13.7 (4.09-4.63) (4.88-5.52) (5.91-6.70) (6.73-7.64) (7.81-8.91) (8.67-9.94) (9.51-11.0) (10.4-12.1) (11.6-13.6) (12.5-14.8) 10-day 4.93 5.86 7.04 7.96 9.22 10.2 11.2 12.2 13.6 14.7 (4.66-5.24) (5.53-6.23) (6.63-7.48) (7.49-8.47) (8.63-9.80) (9.52-10.9) (10.4-11.9) (11.3-13.1) (12.5-14.6) (13.4-15.8) 20-day 6.60 7.80 9.21 10.3 11.9 13.1 14.3 15.6 17.3 18.6 (6.25-6.98) (7.38-8.24) (8.72-9.73) (9.77-10.9) (11.2-12.6) (12.3-13.9) (13.4-15.2) (14.5-16.6) (16.0-18.5) (17.1-20.0) 30-day 8.18 (7.81-8.59) 9.63 (9.17-10.1) 11.2 (10.6-11.7) 12.4 (11.8-13.0) 14.0 (13.3-14.7) 15.2 (14.4-16.0) 16.4 (15.5-17.3) 17.6 (16.6-18.6) 19.3 (18.0-20.4) 20.5 (19.1-21.8) 45-day 10.4 (9.89-10.9) 12.1 (11.6-12.7) 13.9 (13.2-14.5) 15.3 (14.5-16.0) 17.1 (16.2-17.9) 18.4 (17.5-19.3) 19.8 (18.7-20.8) 21.1 (19.9-22.2) 22.9 (21.5-24.2) 24.3 (22.6-25.7) 60-day 12.4 (11.9-13.0) 14.5 (13.9-15.1) 16.3 (15.7-17.1) 17.8 (17.0-18.6) 19.6 (18.7-20.5) 21.0 (20.0-22.0) 22.3 (21.3-23.4) 23.6 (22.4-24.8) 25.3 (23.9-26.6) 26.5 (25.0-28.0) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability hat precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to ToD PF graphical https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.8900&Ion=-79.6222&data=depth&units=english&series=pds 1/3 11/1/2017 Precipitation Frequency Data Server Precipitation depth (in) Precipitation depth (in) 30 25 20 15 10 30 25 20 15 10 PDS-based depth -duration -frequency (DDF) curves Latitude: 35_8900°, Longitude:-79.6222° C C E .E - rl Duration 7n r N r 0 r A ro N ro 2 5 10 25 50 100 200 500 1000 NOAA Atlas 14, Volume 2, Version 3 Average recurrence interval (years) Created (GMT): Wed Mou 1 20:27:41 2017 Back to Toa Maps & aerials Small scale terrain Large scale terrain Average recurrence interval (years) — 1 2 5 10 — 25 — 50 — 100 — 200 — 500 1000 Duration — 5-non — 2-day — 10-rnm — 3-day 15-min — 4-day — 30-min — 7-day — 60-min — 10-aay — 2-hr — 20-eay — 3-hr — 30-day — 6-hr — 45-eay — 12-hr — 60-eay — 24-hr https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage. htnnriat=35.8900&Ion=-79.6222&data=depth&units=english&series=pds 2/3 11/1/2017 Precipitation Frequency Data Server Durham Raleigh Rocky Blacksburg Roanoke 46 .6.. :N i r 0 Winston-Salem ■ u Durham Greensbars • • hail NORTH CAROLINA • Charlotte Mlle 100km -- 1Omr Fayette/ i l l e Large scale map Winston-Salem ail Otte 100km 6fOmi Greensboro • North Carolina Larae scale aerial • Winston-Salem Greensboro • DU -ham . • .:.Rock • Raleigh•• Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.QuestionsAnoaa.00v Disclaimer https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.htnnriat=35.8900&Ion=-79.6222&data=depth&units=english&series=pds 3/3 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Appendix C — Existing Condition Model Results November 15, 2021 13 (Al) `A2) (B1) �2) (1) D Al D A2 A-1 Outfall A-1 <Subca> Reach A-2 Outfall A-2 D B1 (new ubcat) DAC1 B-1 Outfalll B-1 B-2 Outfall B-2 Outfall C Routing Diagram for ExistingConditions Prepared by HDR, Inc, Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC ExistingConditions Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 2 Area Listing (all nodes) Area CN Description (acres) (subcatchment-numbers) 286.100 78 (A1, A2) 1,259.900 77 (B 1, B2, C1) 1,546.000 77 TOTAL AREA ExistingConditions Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 3 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.000 HSG A 0.000 HSG B 0.000 HSG C 0.000 HSG D 1,546.000 Other A1, A2, B1, B2, Cl 1,546.000 TOTAL AREA ExistingConditions Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 4 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 0.000 0.000 0.000 1,546.000 1,546.000 Al , A2, B1, B2, C1 0.000 0.000 0.000 0.000 1,546.000 1,546.000 TOTAL AREA ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 5 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentAl : DA Al SubcatchmentA2: DA A2 SubcatchmentBl: DA B1 SubcatchmentB2: (new Subcat) SubcatchmentCl : DA C1 Link A-1: Outfall A-1 Link A-2: Outfall A-2 Link B-1: Outfalll B-1 Link B-2: Outfall B-2 Link C: Outfall C Runoff Area=235.100 ac 0.00% Impervious Runoff Depth>4.79" Tc=63.3 min CN=78 Runoff=544.52 cfs 93.851 af Runoff Area=51.000 ac 0.00% Impervious Runoff Depth>4.84" Tc=22.0 min CN=78 Runoff=212.86 cfs 20.549 af Runoff Area=439.700 ac 0.00% Impervious Runoff Depth>4.66" Tc=83.4 min CN=77 Runoff=831.96 cfs 170.596 af RunoffArea=80.700 ac 0.00% Impervious Runoff Depth>4.71" Tc=35.0 min CN=77 Runoff=259.40 cfs 31.670 af RunoffArea=739.500 ac 0.00% Impervious Runoff Depth>4.63" Tc=102.9 min CN=77 Runoff=1,219.94 cfs 285.510 af Inflow=544.52 cfs 93.851 af Primary=544.52 cfs 93.851 af Inflow=212.86 cfs 20.549 af Primary=212.86 cfs 20.549 af Inflow=831.96 cfs 170.596 af Primary=831.96 cfs 170.596 af Inflow=259.40 cfs 31.670 af Primary=259.40 cfs 31.670 af Inflow=1,219.94 cfs 285.510 af Primary=1,219.94 cfs 285.510 af Total Runoff Area = 1,546.000 ac Runoff Volume = 602.176 af Average Runoff Depth = 4.67" 100.00% Pervious = 1,546.000 ac 0.00% Impervious = 0.000 ac ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment Al: DA Al Runoff = 544.52 cfs @ 12.85 hrs, Volume= 93.851 af, Depth> 4.79" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Area (ac) CN Description * 235.100 78 235.100 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 63.3 60/ 5507' NRCC 24-hr BI Direct Entry, Subcatchment Al: DA Al Hydrograph soot' NCp-4,00yr44-hr Rainfall=7.42 45O- Runoff Area=235�10b ao RpnOff YOlump=p-3.861-af + + aoo— Runs fff tlepth4 719" 1 1 1 35O Tp=03.3 m i n 300:- 250� 200J 150— 100j 50- CN=78 7 r + r + 1 rt 4 1 rt 4 1 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment A2: DA A2 Runoff = 212.86 cfs @ 12.32 hrs, Volume= 20.549 af, Depth> 4.84" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Area (ac) CN Description 51.000 78 51.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 22.0 Direct Entry, Subcatchment A2: DA A2 Hydrograph 230,' - T T r 7 7 T r 212.86 cfs 210 ' + N IRC C-2441r- V - soJ' NRCC-100yr--Z4-11r R,1ain,fali=7.4211 180,'fi-RunoffAr-ea=54.-O04lac---_--rt--t 170 1RpncIff 1 ▪ 0 l ,l m -Z6. 514S 111af 150J' 1lanaf€3ept�44" + 140 1 =T 212 0' m � i1n ▪ 1301 1 1 � - 1 1 1 1 1 1 1 3 120 -N=7-8T + r r 1 r 1 100= 90 I I I I 80— — 1 1 J + + L 70J - 60 50 - 40 30 20 10 0 ▪ 1 + - + + 1 7 T + T 1 T T T 11 1 T T T 1 + r 1 1 + I+ 1 4 4 + + 1 1 + + — — + — — 1 — — + — — + 1 1 1 + — — + / • + 1 1 + r • + 4- • + r 1 1 1 1 + y — — + - - r 1 1 1 rt - - + J L L 1 1 1 1 + 1 + r T + 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) • Runoff ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment B1: DA B1 Runoff = 831.96 cfs @ 13.11 hrs, Volume= 170.596 af, Depth> 4.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Area (ac) CN Description * 439.700 77 439.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 83.4 Direct Entry, 900- 850- 800- 750 7OO- 650J 600—:' • 550 ▪ 500 450� 0 u- 400= 350= 300- 250= 200- 150= 100- 50- Subcatchment B1: DA B1 Hydrograph 1 1 1 1 I 1 1 1 1 L 1 i N Rir-24-- r Bt ▪ L NRCC-100yr-24-hr Rainfall R'undff Arela=439.700 ad Runoff Volurn 17-0. -Runff€ 43eptih'48G" Tp=93.4 min CN=77 1 + 1 1 1 L L L L 831.96 cfs 698of =7.42" 7 7 T 7 T ▪ 7 1 ▪ 1 1 1 1 1 1 1 ▪ L 7 1 1 1 L L 1 L LI // 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) • Runoff ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment B2: (new Subcat) Runoff = 259.40 cfs @ 12.49 hrs, Volume= 31.670 af, Depth> 4.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Area (ac) CN Description 80.700 77 80.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 35.0 Direct Entry, Subcatchment B2: (new Subcat) Hydrograph 280-L--/ �r i i 7 7 t r 7 -t 11259.40 cfs I 1 260J NRCC 24-hlr BI 240J' NRCC-100yr-224-her Rainfall=7142"1 220 Runoff Area=80.700 ac 2oo� Runoff Volume=1.670 -r ofII 180J ' Runoff bepth>4.71" 160 Tp=35.0 min CN-77 T 14o,- 60- 40- 2 1 1 i L r 4- Tri 1 iLi L 1 1 L - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) • Runoff ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment Cl: DA C1 Runoff = 1,219.94 cfs @ 13.37 hrs, Volume= 285.510 af, Depth> 4.63" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Area (ac) CN Description * 739.500 77 739.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 102.9 Direct Entry, 1,300J 1,200� 1,100- 1, 000L- 900" 800- Tp=192T9min 7007' CN=77 Subcatchment C1: DA C1 Hydrograph N N 6007 500- 400- 300— - 2007 = T 100- RCC 24-hr 8 RCC-00Yr-24-hr F ainfal =7 42' unbff Area=39.r0b ac unosff Volume=4,519a unaff iDept-h: 443'1 1,219.94 cfs 5 6 II i 1- r r r it it rt 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) • Runoff ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 11 Summary for Link A-1: Outfall A-1 Inflow Area = 235.100 ac, 0.00% Impervious, Inflow Depth > 4.79" for NRCC-100yr-24-hr event Inflow = 544.52 cfs @ 12.85 hrs, Volume= 93.851 af Primary = 544.52 cfs @ 12.85 hrs, Volume= 93.851 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 600— 550J 500J 450� 100J 50- 1 L Link A-1: Outfall A-1 Hyd rog raph [inflow Area-215,i QO 1 — 1 L 1544.52 cfs L 1 L L 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 12 Summary for Link A-2: Outfall A-2 Inflow Area = 51.000 ac, 0.00% Impervious, Inflow Depth > 4.84" for NRCC-100yr-24-hr event Inflow = 212.86 cfs @ 12.32 hrs, Volume= 20.549 af Primary = 212.86 cfs @ 12.32 hrs, Volume= 20.549 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Link A-2: Outfall A-2 Hyd rog raph 2307:- / - 2204' 210 200� - 190 - 180 170- - 160- / - 150- - 140- - 130i- - 3 1204" z- o 110 u- 100' - 90J, - 80' - 70J - 10 60J - 50J 40- 30= 4 4 1 4 L 4 4 1 4 1 4 L 1 1 1 L 1 1 L _I 212 86 cfs I L f� 0 Ape - .000 12.86 cfs 1 1 4 L L 1 1 L L 4 4 1 L r r L —I t Y Y -rI Y Y Y —IY Y 1 Y Y 41 I I I r r ,.%1 1 1 +I0 II 4 —1 1 1 L 1 / 1 1 1L 1 1 1L 1 l 7 T 1 1 1 1 1 1 1 ' i I. Ti 1r 7 1 1r 1 1 T 0 1 2 3 4 5 6 7 8 9 + 10 11 12 13 14 15 16 17 Time (hours) 18 19 20 21 22 23 24 C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 13 Summary for Link B-1: Outfalll B-1 Inflow Area = 439.700 ac, 0.00% Impervious, Inflow Depth > 4.66" for NRCC-100yr-24-hr event Inflow = 831.96 cfs @ 13.11 hrs, Volume= 170.596 of Primary = 831.96 cfs @ 13.11 hrs, Volume= 170.596 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 900' 850J 800 750- 700'� 650� 600 ' 550� o ▪ 500 3 450J LL 400- 350J 300� 250 - 200- 150= 100� 50 Link B-1: Outfalll B-1 Hyd rog raph I I I II -I + 831.96 cfs Clfiolir Arpa+TVVI��0ia31.96c�A G/ dOI + r + + + + 1- 4- 4- + + + + + Hi- '1- + 1 i +1 1- 1 1 1- + I + 1 1 1- + 1 i + 11 1- 1 1 1- + Hi- '1- 11- i + i + + 4 ~ I 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 14 Summary for Link B-2: Outfall B-2 Inflow Area = 80.700 ac, 0.00% Impervious, Inflow Depth > 4.71" for NRCC-100yr-24-hr event Inflow = 259.40 cfs @ 12.49 hrs, Volume= 31.670 af Primary = 259.40 cfs @ 12.49 hrs, Volume= 31.670 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 0 LL Link B-2: Outfall B-2 Hyd rog raph 280" 260� 2407" 220- 200- 180- 160- 140J 120J 100:" 807" 60= 40= 20- 0 nf10 ,v-Are =$Q I L 4 4 1 iL I I I I l il II L 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Time (hours) 19 20 21 22 23 24 C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-100yr-24-hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 15 Summary for Link C: Outfall C Inflow Area = 739.500 ac, 0.00% Impervious, Inflow Depth > 4.63" for NRCC-100yr-24-hr event Inflow = 1,219.94 cfs @ 13.37 hrs, Volume= 285.510 of Primary = 1,219.94 cfs @ 13.37 hrs, Volume= 285.510 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 1,3007_ I !If ow Arpa77 1,2007' 1,100� ,ter 1,000� L 900: 800� 700' 6004 5007' 400- r 300- 200 100:- 0 Link C: Outfall C Hyd rog raph 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 16 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentAl : DA Al SubcatchmentA2: DA A2 SubcatchmentBl: DA B1 SubcatchmentB2: (new Subcat) SubcatchmentCl : DA C1 Link A-1: Outfall A-1 Link A-2: Outfall A-2 Link B-1: Outfalll B-1 Link B-2: Outfall B-2 Link C: Outfall C Runoff Area=235.100 ac 0.00% Impervious Runoff Depth>2.70" Tc=63.3 min CN=78 Runoff=307.86 cfs 52.962 af Runoff Area=51.000 ac 0.00% Impervious Runoff Depth>2.73" Tc=22.0 min CN=78 Runoff=121.16 cfs 11.609 af Runoff Area=439.700 ac 0.00% Impervious Runoff Depth>2.60" Tc=83.4 min CN=77 Runoff=463.81 cfs 95.286 af Runoff Area=80.700 ac 0.00% Impervious Runoff Depth>2.63" Tc=35.0 min CN=77 Runoff=145.50 cfs 17.713 af Runoff Area=739.500 ac 0.00% Impervious Runoff Depth>2.59" Tc=102.9 min CN=77 Runoff=679.56 cfs 159.375 af Inflow=307.86 cfs 52.962 af Primary=307.86 cfs 52.962 af Inflow=121.16 cfs 11.609 af Primary=121.16 cfs 11.609 af Inflow=463.81 cfs 95.286 af Primary=463.81 cfs 95.286 af Inflow=145.50 cfs 17.713 af Primary=145.50 cfs 17.713 af Inflow=679.56 cfs 159.375 af Primary=679.56 cfs 159.375 af Total Runoff Area = 1,546.000 ac Runoff Volume = 336.945 af Average Runoff Depth = 2.62" 100.00% Pervious = 1,546.000 ac 0.00% Impervious = 0.000 ac ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment Al: DA Al Runoff = 307.86 cfs @ 12.86 hrs, Volume= 52.962 af, Depth> 2.70" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 235.100 78 235.100 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 63.3 Direct Entry, 340- 320—:' Subcatchment Al: DA Al Hydrograph ▪ 1 1 L I 1 L 300; N 2801.' N 1307.86 cfs RCC 24-fir a RCIC-10yr-24hr Rainfall=5.04' 2607' Runoff-Ar =23 �'Lb0 c 240 -Rub#,Vol un a=296-2 af - - - T • 200 'FI Tc=938 min • 1807' I 0 160=II CN=78 LT__ fi 7 rt r 7 rt 140- 120� ,L 100= 80- 60= z k + + + + + + + 40= zI 20I 0 9 10 11 12 13 14 Time (hours) 15 16 ▪ r ▪ r 7 Y r 17 18 19 20 21 22 T T 4 + T T 4 rt t + rt + 4 + 23 24 • Runoff ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment A2: DA A2 Runoff = 121.16 cfs @ 12.32 hrs, Volume= 11.609 af, Depth> 2.73" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 51.000 78 51.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 22.0 130-1 120— 110—/ 100-1 90 80 70-- 60-1 50- Direct Entry, Subcatchment A2: DA A2 Hydrograph + 1I —I 121.16 cfs NRCC 24-hr R 2/ 1 1 1 L J 1 NRCIC-10yr-24hr Rainfall=5.p4'"I Runoff Area=51:00b ac I / Runoff iVolunne=11605 at T / gunpffrDe t11>2,73" /T'►c= 2.o min- �.IN=78 ▪ 1 1 1 1 1 1 T 1 L L L L 1 1 1 ▪ r 9 10 11 12 13 14 15 16 1 Time (hours) + 4 1 4 7 18 19 20 21 22 23 24 • Runoff ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment B1: DA B1 Runoff = 463.81 cfs @ 13.14 hrs, Volume= 95.286 af, Depth> 2.60" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 439.700 77 439.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 83.4 Direct Entry, Subcatchment B1: DA B1 Hydrograph 500J T 480 r 460- T _N 440 420; -NRCC--10yr 24-hr`- Ra inf al � =5. 1" - - 0J 380JT RUnOff!�rAr01430.760 _aC 7 T 38-- 360 RUiibff iVoi un a 9-5,28S of - - - t 340;- 1r I I I I I I I I I 320 L Runoff-Deptt >2�-6-0!I 1 1 _L w 300---/ T y �. I I I I I I 13280J - -Tc=,,,,, 4 m n- 1 I 1 1 _L O 20� T CN=77 4 1 1 1 1 4 240� �- 1 1 _L L L 1 _L LL 220= T 200 ) 180° T I I I I I I I 160: 1 I 1 4 _L 1 I I 1 1 _L 140� 120=k 100 80° r 60- T I I I I I 40= k 1 1 _L 1 L 1 L L I 1 7 7 T r 1 1 1 7 T T 1 /'► 1 1 _L I I 1 4 1 463.81 c RCC 7.4- r17 20J 0- 1 L I I I 1 L 7 T r 1 7 T 1 1 1 I I I 1 _L 1 1 1 I I I 1 _L 7 T r 1 7 T 1 L L I I I 1 _L 1 1 L I I I 1 _L 1 1 1 I I I 1 _L L I I I 1 _L I 1 I 1 1 I I 1 1 1 1 I I I 1 1 1 1 1 L I I 1 1 1 -- — I— _W I 1 1 L I I I 1 _L 1 1 1 I I I 1 _L I I I I I 1 1 1/ I I 1 1 1 I I 1 1 I I I I I I I I I ii I I I I I I I I 1 4 _L L J 4 _L — l-- L 1 _L 4 4 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) • Runoff ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 20 Summary for Subcatchment B2: (new Subcat) Runoff = 145.50 cfs @ 12.50 hrs, Volume= 17.713 af, Depth> 2.63" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 80.700 77 80.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 35.0 Direct Entry, 160 150= Subcatchment B2: (new Subcat) Hydrograph I r r r 1 1 1 1145.50 cfs QNVy_-nr y 140= t NRILII I I I 130Jt NICK-"-0-Vr-24h` Rainfall-=5.94Ir / 120�' RunoffArea=80:170b'ac 11oJ' TRunbffVolunhe17�713 of +I/ 100�r guncilff:Depthi>2.[63''Or (yn 80 ' CN_=-7T a 7n-/ I I I I I I I I 0 ' 60 ' 50J 41 407- 30� 1 20- 0- 1 ✓ r L - I r r r r T I hi HI 11 T L L 1 1 9 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 21 22 23 24 • Runoff ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment Cl: DA C1 Runoff = 679.56 cfs @ 13.39 hrs, Volume= 159.375 af, Depth> 2.59" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 739.500 77 739.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 102.9 Direct Entry, Subcatchment C1: DA C1 Hydrograph I L 1 1 L 750- 700J NRCC-144rrB 650: 1 - NKC---1-0yr-24hr Ra1nfalt=5 4'k 600� -Runoff-Area=7 t1.5b0 ac 550' Ru nbfrVol u n}ie=1-59.3?5 500-' 1 1 1 1 1 -i I 1679.56 cfs I I Ti01441 I I I I ? r I I 1 i i r 450— gunpffDeptlp>2,59" Tc= 021.9 min 4007- 1 350J' CN=771 LT_I I I I 300- 1 1 1 1 1 250-1- r ri 1 1 1 1 1 200-'' 11 1 1 1 1 150= 1 1 1 1 1 100r- '11 50= 1 r 0- L L 1-1 L Ir Ir II r 9 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 21 22 23 24 • Runoff ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 22 Summary for Link A-1: Outfall A-1 Inflow Area = 235.100 ac, 0.00% Impervious, Inflow Depth > 2.70" for NRCC-10yr-24hr event Inflow = 307.86 cfs @ 12.86 hrs, Volume= 52.962 af Primary = 307.86 cfs @ 12.86 hrs, Volume= 52.962 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs N o 0 E 3407" 320� 300/ 280� 260/ 240/ 220/ 200/ 180/ 160= 140= 120- 100= Link A-1: Outfall A-1 Hyd rog raph 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 23 Summary for Link A-2: Outfall A-2 Inflow Area = 51.000 ac, 0.00% Impervious, Inflow Depth > 2.73" for NRCC-10yr-24hr event Inflow = 121.16 cfs @ 12.32 hrs, Volume= 11.609 af Primary = 121.16 cfs @ 12.32 hrs, Volume= 11.609 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 0 LL 130- 120- 100J 907- 801- 70-' 60- 50J 40J 30- 20� 10J 0 Link A-2: Outfall A-2 Hyd rog raph nff ow Area,= t, 121.16 cfs I - III II 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) L 7 C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 24 Summary for Link B-1: Outfalll B-1 Inflow Area = 439.700 ac, 0.00% Impervious, Inflow Depth > 2.60" for NRCC-10yr-24hr event Inflow = 463.81 cfs @ 13.14 hrs, Volume= 95.286 af Primary = 463.81 cfs @ 13.14 hrs, Volume= 95.286 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 500" 450- 400- 350— 300:" 250-1" 200J 150— 100- Link B-1: Outfalll B-1 Hyd rog raph 4 4 Inflow Ara=439 700 0 4 50- 0 fl/•lll/(• • 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Time (hours) 4 4 1- I 4 4 14 15 16 17 18 19 20 21 22 23 24 C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 25 Summary for Link B-2: Outfall B-2 Inflow Area = 80.700 ac, 0.00% Impervious, Inflow Depth > 2.63" for NRCC-10yr-24hr event Inflow = 145.50 cfs @ 12.50 hrs, Volume= 17.713 af Primary = 145.50 cfs @ 12.50 hrs, Volume= 17.713 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Link B-2: Outfall B-2 Hyd rog raph 160, 150- 140- 130� 120- 110- 100- 90� 80- 70� 60- 50- 40� 30 20J 10- -;:or 1 ;T T nfloW area=$0. T 0 1 2 3 4 5 T i i T 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) C Inflow ❑ Primary ExistingConditions NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 26 Summary for Link C: Outfall C Inflow Area = 739.500 ac, 0.00% Impervious, Inflow Depth > 2.59" for NRCC-10yr-24hr event Inflow = 679.56 cfs @ 13.39 hrs, Volume= 159.375 af Primary = 679.56 cfs @ 13.39 hrs, Volume= 159.375 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 7507" 700 650- 6001: 5507" 500� 450� 400- 350- 300'. 2507." 200- 150= 100 50 0 Link C: Outfall C Hyd rog raph 1_ L 4 1 1 4 r 679.56 cfs 1 1 1 tnf!oi Ares+-745 a0679 i i i r L 1 II- 4 'T r I I I 4- 1- 4 II 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) C Inflow ❑ Primary STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Appendix D — Proposed RCN 4 I November 15, 2021 Greensboro Megasite 01 Curve Numbers Date: 11/15/2021 By: LVL Basin "Al" Existing Land Use Cover Type Area % CN Wtd. CN Impervious 44.3 ac 44.6% 97 43.24 Grass (D soils) 55.0 ac 55.4% 92 50.99 Total 99.3 ac 100.0% 94.23 Composite CN 94.23 Use CN = 94.2 Basin "A2" Existing Land Use Cover Type Area % CN Wtd. CN Impervious 66.3 ac 52.9% 97 51.34 Grass (D Soils) 59.0 ac 47.1% 92 43.30 Total 125.3 ac 100.0% 94.65 Composite CN 94.65 Use CN = 94.6 Basin "A3.U" Future Land Use Cover Type Area % CN Wtd. CN Cultivated Crops (C Soils) 0.8 ac 1.4% 82 1.17 Deciduous Forest (C Soils) 0.9 ac 1.8% 66 1.16 Developed, Open Space (C Soils) 0.1 ac 0.1% 78 0.08 Hay/Pasture (C Soils) 3.0 ac 5.5% 73 4.03 Cultivated Crops (D Soils) 9.1 ac 17.0% 86 14.58 Deciduous Forest (D Soils) 33.5 ac 62.3% 73 45.46 Hay/Pasture (D Soils) 7.8 ac 14.6% 79 11.51 Mixed Forest (D Soils) 0.4 ac 0.7% 73 0.49 Total 53.9 ac 100.0% 76.08 Composite CN 76.08 Use CN = 76.1 Greensboro Megasite 01 Curve Numbers Date: 11/15/2021 By: LVL Basin "A4.U" Future Land Use Cover Type Area % CN Wtd. CN Cultivated Crops (C Soils) 2.0 ac 5.5% 82 4.50 Deciduous Forest (C Soils) 0.4 ac 1.0% 66 0.64 Developed, Open Space (C Soils) 0.1 ac 0.2% 78 0.18 Hay/Pasture (C Soils) 1.5 ac 4.0% 73 2.91 Cultivated Crops (D Soils) 0.0 ac 0.0% 86 0.00 Deciduous Forest (D Soils) 6.8 ac 18.5% 73 13.47 Developed, Low Intensity (D Soils) 0.9 ac 2.3% 93 2.16 Developed, Medium Intensity (D Soils) 0.2 ac 0.6% 94 0.56 Developed, Open Space (D Soils) 4.5 ac 12.2% 84 10.28 Evergreen Forest (D Soils) 0.9 ac 2.5% 73 1.82 Hay/Pasture (D Soils) 14.7 ac 39.8% 79 31.45 Mixed Forest (D Soils) 4.3 ac 11.6% 73 8.48 Open Water 0.7 ac 1.8% 100 1.80 Woody Wetlands (D Soils) 0.0 ac 0.0% 86 0.00 Total 37.0 ac 100.0% 78.25 Composite CN 78.25 Use CN = 78.3 Basin "B1" Existing Land Use Cover Type Area % CN Wtd. CN Impervious 177.9 ac 63.8% 97 61.89 Grass (D soils) 100.9 ac 36.2% 92 33.30 Total 278.8 ac 100.0% 95.19 Composite CN 95.19 Use CN = 95.2 Basin "B2.U" Future Land Use Cover Type Area % CN Wtd. CN Deciduous Forest (D Soils) 25.0 ac 74.4% 73 54.33 Developed, Low Intensity (D Soils) 0.1 ac 0.3% 93 0.26 Developed, Open Space (D Soils) 0.2 ac 0.5% 84 0.39 Evergreen Forest (D Soils) 1.6 ac 4.8% 73 3.53 Hay/Pasture (D Soils) 0.8 ac 2.5% 79 2.00 Mixed Forest (D Soils) 5.8 ac 17.3% 73 12.61 Open Water 0.1 ac 0.2% 100 0.18 Total 33.5 ac 100.0% 73.31 Composite CN 73.31 Use CN = 73.3 Greensboro Megasite 01 Curve Numbers Date: 11/15/2021 By: LVL Basin "B3.U" Future Land Use Cover Type Area % CN Wtd. CN Deciduous Forest (C Soils) 0.8 ac 1.3% 66 0.85 Hay/Pasture (C Soils) 3.8 ac 6.1% 73 4.47 Deciduous Forest (D Soils) 34.8 ac 56.2% 73 41.04 Evergreen Forest (D Soils) 0.8 ac 1.2% 73 0.90 Hay/Pasture (D Soils) 17.0 ac 27.5% 79 21.74 Mixed Forest (D Soils) 4.7 ac 7.6% 73 5.52 Open Water 0.0 ac 0.1% 100 0.06 Total 62.0 ac 100.0% 69.25 Composite CN 69.25 Use CN = 69.3 Basin "Cl" Future Land Use Cover Type Area % CN Wtd. CN Impervious 110.4 ac 39.6% 97 38.42 Grass (D soils) 144.0 ac 51.6% 92 47.50 Total 254.4 ac 91.2% 85.92 Composite CN 85.92 Use CN = 85.9 Basin "C2" Existing Land Use Cover Type Area % CN Wtd. CN Impervious 214.9 ac 77.1% 97 74.77 Grass (D soils) 64.5 ac 23.1% 92 21.28 Total 279.4 ac 100.2% 96.05 Composite CN 96.05 Use CN = 96.0 Greensboro Megasite 01 Curve Numbers Date: 11/15/2021 By: LVL Basin "C2.U" Future Land Use Cover Type Area % CN Wtd. CN Developed, Low Intensity (B Soils) 0.1 ac 0.1% 88 0.06 Developed, Medium Intensity (B Soils) 0.2 ac 0.1% 89 0.09 Hay/Pasture (B Soils) 0.4 ac 0.2% 61 0.14 Deciduous Forest (C Soils) 6.7 ac 3.6% 66 2.40 Developed, Low Intensity (C Soils) 2.9 ac 1.6% 90 1.42 Developed, Open Space (C Soils) 2.5 ac 1.4% 78 1.06 Evergreen Forest (C Soils) 0.3 ac 0.2% 66 0.11 Hay/Pasture (C Soils) 31.0 ac 16.9% 73 12.35 Herbaceous (C Soils) 1.9 ac 1.0% 75 0.77 Mixed Forest (C Soils) 3.4 ac 1.9% 66 1.23 Shrub/Scrub (C Soils) 3.2 ac 1.7% 55 0.95 Deciduous Forest (D Soils) 40.8 ac 22.3% 73 16.25 Developed, High Intensity (D Soils) 0.4 ac 0.2% 94 0.23 Developed, Low Intensity (D Soils) 3.0 ac 1.6% 93 1.53 Developed, Medium Intensity (D Soils) 1.2 ac 0.7% 94 0.63 Developed, Open Space (D Soils) 11.9 ac 6.5% 84 5.45 Evergreen Forest (D Soils) 5.0 ac 2.7% 73 1.98 Hay/Pasture (D Soils) 53.1 ac 29.0% 79 22.91 Herbaceous (D Soils) 0.5 ac 0.2% 85 0.21 Mixed Forest (D Soils) 4.6 ac 2.5% 73 1.83 Shrub/Scrub (D Soils) 9.9 ac 5.4% 62 3.34 Open Water 0.3 ac 0.1% 100 0.14 Total 183.0 ac 100.0% 75.10 Composite CN 75.10 Use CN = 75.1 Greensboro Megasite 01 Curve Numbers Date: 11/15/2021 By: LVL Basin "C3.U" Future Land Use Cover Type Area % CN Wtd. CN Deciduous Forest (C Soils) 41.8 ac 25.7% 66 16.99 Developed, Low Intensity (C Soils) 0.1 ac 0.1% 90 0.07 Developed, Medium Intensity (C Soils) 0.1 ac 0.1% 93 0.08 Developed, Open Space (C Soils) 2.5 ac 1.6% 78 1.22 Hay/Pasture (C Soils) 13.9 ac 8.6% 73 6.26 Herbaceous (C Soils) 0.4 ac 0.3% 75 0.19 Mixed Forest (C Soils) 4.1 ac 2.5% 66 1.66 Woody Wetlands (C Soils) 0.5 ac 0.3% 86 0.24 Deciduous Forest (D Soils) 59.1 ac 36.4% 73 26.55 Developed, Low Intensity (D Soils) 0.7 ac 0.5% 93 0.43 Developed, Open Space (D Soils) 2.2 ac 1.4% 84 1.16 Evergreen Forest (D Soils) 14.3 ac 8.8% 73 6.42 Hay/Pasture (D Soils) 18.9 ac 11.6% 79 9.17 Mixed Forest (D Soils) 3.5 ac 2.2% 73 1.58 Open Water 0.2 ac 0.1% 100 0.09 Total 162.4 ac 100.0% 72.14 Composite CN 72.14 Use CN = 72.1 STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Appendix E — Proposed Pond Calculations and Grading November 15, 2021 15 1 2 3 4 5 6 7 8 OHE )1 f� Irr,, >ll►I EXISTING LINAGE �ti/„� AREA (TYP) �11 POND B2 EXISTING STREAM (TYP) - - (Ji' UNDERDRAIN INSTALLED IN 1 \ v r FILLED STREAM - — 11 I \"- , BED FOR GROUND \��' ��' )ilq , WATER RELIEF, TYP. `-` , _ \��\\II � � 1 //7A) i )1 l , ; . / - . .::,. ? cr 3 /-a,-•-:;F:5/ \I ) fl:1- L 1- 1 I J 47 r v J, r 1 III 1 w� �1(1 �!(% jr `� \: i ► �({((-4� 1 f II S\��--� Iv\��� j1� �� -��- 1 r f. rrfe4 ( (((\("� _ ��\� — . •-"./-r---W%-‘,-) j 2 - `/ .. ��j�� j/ 1 r J, f fl (r -:..17__-_ 1 1 'I I V !` �����1(J(l ✓�//r��.1� • '--,i2.r-)1(yZ(�Yf \ '''/ / igki -44.- --s.-/- k -------:--\ ''''--z--' »7" ifi,iekY III /.\1'\{1.,,IkA)\(_._-__11(-;4----kr-----;;I:\l'-%:\1\--i-:-.-------;\\ S-----5-\-'- --.-N'-----! \itit-5S----T71:7fli .//) Al:: 1\1 -_-__ _. 7 , — .-__L, ,.,>:.----,"_- i >)\1.kc. -,-,----.,--, '-'-'"-------->"--1-4.4K(0- ( \\k., 17,,..(f.71% %(l!11��\~ `_}��\�\``\� )�}�r/%}��\\\_` STREAM OFFSET • /1 ��--��// fir/ ji'' = �,� ; k , IMPACTED TYP (\(� %}rr/ r ��/ � 1 >�/'� \1 ; . . (TYP) ) 1!�" J /f/rl/ice .f,�� �livf((k r�<<<�- � � t �{111�(/` � rjj J �/f �t{C`/ram/� �1 {% i/ '''1, '*, �ttit !/,: - ` :, / \ !1J 1 \ ti\��/ 11 f � �.�\�t�l\\ 5),11)111/ ��\� �� It��ll ii:::.....:::,...,,-.k..i•:::\\\\�Si 11�' 1111ll//�ij1(/ {\t``^�� � , ) > >>�/Ji}t�rr , \ ;}( /( �{ �-•�c �� J'� ! ///jS 1l s:-_--\2-- i 4(0 1 ' ) ' il • •--1},01 �'�,_ 4.�� ��ihI11 \1�1dILam, `', /�li ���.�;'�����i�s!//(\1t �\,_` -7 ., » �A1,� `:11 j:61: 1lW(\1 ' \l\� 4j\\ _ >/_'� ////��1`vs:: tom. —\ ►l�111»���J � �/%///��%// � l \r--�\\�� �, . —/ ��l � �(/ ll1 ��S` � � Jim�;I:1\t\i:\11) Bit�lii�i/%�/�_%/// '', . , ,I, I� 55)S(f f (il/f/��/l���i/��� (� %/� ® ��\��t�>tls�srrll//(/,f;�(I/�/1((rdSfif 1r11�������—=��i��\\�� tl HDR Engineering Inc. of the Carolinas 440S. Church Street, Suite 1000 Charlotte, NC 28202 704.338.6700 N.C.B.E.L.S. License Number: F-0116 ISSUE DATE DESCRIPTION PROJECT MANAGER VICKIE M. MILLER, AICP, PWS PROJECT ENGINEER DAVID BAKER, PE DESIGN ENGINEER WES TURLEY, PE DRAWN BY JENNIFER PALONI, EIT DRAWN BY JACOB RUDISILL CHECKED BY ROBERT BAYSDEN, PE PROJECT NUMBER 10068163 GREENSBORO RANDOLPH MEGASITE FOUNDATION GREENSBORO RANDOLPH MEGASITE RANDOLPH COUNTY, NORTH CAROLINA STORMWATER EXHIBIT OVERALL FILENAME SCALE 01 C-BG01-08.dwg 1 "=500' SHEET / / / \\ 1 ‘S\‘'S MAIN POOL J 1) & A BOTTOM OF SHELF oik\EL 677.5_ NORMAL,POOL EL1 ,�URFACEAREA�6&,544 SF \ �\ / —TOPOFSHELF �� \ / / / / EL 678:5- � \ // \ \ \\\ / /// Z — \ \\ \ \ ) I / \\\ \ \\ \\ \\ / /1 J / \ \ \ \ \ / \ \\ \\ \ 1 / ,\ // \ \ \ / / \ \ \ l \ 1 ' 1 I /// //\\ \ \ \ \ \ \\\ \\ \\ \ \ / / J 1_ \ \ \ \ /i ( ) 1 /' \ \ \ '\ \ '\ 1 ) / / \ \ \ / / I / / / 7—�\\'\� \ \ \ / J / / I / /` \� \ ) I / / I/1// / ,N\� ` `L_� / / / _ �\ I\ \ \ 1 \ I /' ` ` . \ \ \ \ - �7 / 1 \ I I / 7 \ o\ 1,/ 1 1) 1 l 1 / -- c � - -- �• / / /// / )/ �� �\ �� > / / // / / / 1 / \ I / r/ / 11//)//-� ,-c �/Or//( /�)/1/ /^\\ / I I I /�/./- 1 / / \ \ S 1 L711','/ t/ // //t �/�(1\ 1 1 1 1 1 1 ��L-Aty / /hip.�IratiliPilff- � �►�01 /// / /IlV( f 11((/// 4:'.11 / / / / / ) HDR Engineering Inc. of the Carolinas 440 S. Church Street, Suite 1000 Charlotte, NC 28202 704.338.6700 N.C.B.E.L.S. License Number: F-0116 / \710 \ \ \ \ \ 1 \ \ \ \ \ \ \ \ \ \ N \ / \ \ / 4. \ \ \ \ _ 700 J ,I 1\ \ \ / '1 \ ,__\\\ oN� l \ ` \ N \ �\ 1\ \ 1 _ y \� \ \ \ 690 \ \ \ \ `/ �� \\� \ \\ \ _ \ \ \ / �\ \ �\ \\ \ (/ ( 7 — j\\\\�`680 ,� I —Th \—�\ - - �/ / ISSUE DATE DESCRIPTION N x�o N r- co ii Lu _.,1 M a 0 STA 6+99.E RIM = 688.( 60"OUT (S WATER QUALITY VOLUME EL 681 F NORMAL POOL EL 678 i414 LF 60 @ 0.24% SEDIMENT STORAGE / �— EL 672 _ - !/ - — O O O O () O m O O h O .1- O Co O O co co O r O O O O co co O • O O 6) Cr) O co Co is) O co 6) O co ~ O LS) LC) O 6) O 695.89 695.2 00 L!) ,_ o) coO O CO N r to 0) O co r O co O) O COco 1CO 693.11 691.3 c'o -N d7 CO O CO I- N O co O 00 O ' d - O o 00 OD O co co co N o O COCD co 692.34 691.3 co co N 00 T co O CO d ~ c co co Ln O c0 Li,co CO 00 00 CO I O co O O c6 00 CO N ti c0 • ti r- (o C.0 CO 667.72 co ,- ti 7r 6) O CO O a) O coO PROJECT MANAGER VICKIE M. MILLER, AICP, PWS PROJECT ENGINEER DAVID BAKER, PE DESIGN ENGINEER WES TURLEY, PE DRAWN BY JENNIFER PALONI, EIT DRAWN BY JACOB RUDISILL CHECKED BY ROBERT BAYSDEN, PE PROJECT NUMBER 10068163 0 1" STORMWATER EXHIBIT WET POND A3 2,, FILENAME GREENSBORO RANDOLPH MEGASITE FOUNDATION GREENSBORO RANDOLPH MEGASITE RANDOLPH COUNTY, NORTH CAROLINA SCALE 01 C-BG01-08.dwg 1 "=60' SHEET Source: NCDEQ Stormwater Design Manual, C-3. Wet Pond - Apr7 2017 MDC 1-2 Main Pool Surface Area, Volume, and Depth Total Drainage Area to Pond (ac) = 224.60 Post -Developed Impervious Area (ac) = 110.60 Average Pool Depth Davg (ft) = 4.8 Pond Bottom Elevation (ft) = 672.00 Bottom of Sediment Storage Elevation (ft) = 671.00 Permanent Pool elevation (ft) = 678.00 Ratio (SAIDA) for Davg 1.31 Surface Area Required (ft2) 128165 Surface Area Provided (ft2) 168544 or 49.2 2.94226 acres Table 1: Piedmont and Mountain SAIDA Table % Permanent Pool Average Depth (ft) Impervious 3.0 4.0 5.0 6.0 7.0 8.0 10 0.51 0.43 0.37 0.30 0.27 0.25 20 0.84 0.69 0.61 0.51 0.44 0.40 30 1.17 0.94 0.84 0.72 0.61 0.56 40 1.51 1.24 1.09 0.91 0.78 0.71 50 1.79 1.51 1.31 1.13 0.95 0.87 60 2.09 1.77 1.49 1.31 1.12 1.03 70 2.51 2.09 1.80 1.56 1.34 1.17 72 2.59 2.15 1.85 1.61 1.40 1.22 80 2.92 2.41 2.07 1.82 1.62 1.40 90 3.25 2.64 2.31 2.04 1.84 1.59 100 3.55 2.79 2.52 2.34 2.04 1.75 Average Pond Depth Davg = Where: Vahea = Where: VP P-lrshe l f Abottomofshelf Den VPP Vshea Amaom or and f 0.6 • Depth.ax eye, eheIf D. over shelf Peri meterpermanent pod Average depth in feet Total volume of permanent pool (feet3) Volume over the shelf only (feet') - see below Area of wet pond at the bottom of the shelf (feet2) * Perimeterper,,,1, ' Widtha.bma.wd pert of cheIf Widtheebmsmedpart oFshelf = Depth of water at the deep side of the shelf as measured at perrnanent pool (feet) Perimeter of permanent pool at the bottom of the shelf (feet) Width from the deep side to the dry side of the shelf as measured at permanent pool (feet) Volume of Perm Pool VPP (ft3)= 783488 Shelf Bottom Area Abot (ft3)= 164112 Max Pool Depth Above Shelf Dmax (ft)= 0.5 Perimeter of Shelf Bottom Permm (ft)= 1394 Width of Submerged Shelf W sub (ft)= 3.0 Volume Over Shelf Vshelf (ft3)= 1046 Average Depth Davg (ft)= 4.77 Water Quality Volume Rv Where: 0.05 + 0.9*IA Ru Ik Runoff coefficient (unitless) Impervious fraction (unitless) DV = 3630*Rn*Rv*A Where DV RD A Design volume (cu ft) Design storm depth (in) Drainage area (ac Runoff Coefficient Rv= 0.5 Design Storm Depth RD (in)= 1.0 Water Quality Volume (ft3)= 402095 Depth of Water Quality Volume Release (ft) 3.00 or 9.2 3.1 ac-ft acres Orifice Sizing WQv Stage in Pond (ft) 681.00 WQv Release Period (days) 4.0 WQv Release Rate (cfs) 1.16 Avg Head (ft) = (WQv Elev - Perm Pool Elev) 12 = 1.50 Estimated Orifice Diameter (in) 6.0 Orifice Diameter Provided (in) 6.0 Actual Release Rate (cfs) 1.16 Actual WQv Release Period (days) 4.0 Pond Grading Normal Pool Stage - Storage Data Elevation surtace Area (sf) Area (ac-ft) Inc. Vol. (ac- ft) Iotal Vol. (ac-ft) !Jet. Vol. (ac- ft) Notes 672.00 99117 2.28 0.000 674.00 113009 2.59 4.870 4.870 676.00 144060 3.31 5.901 10.771 677.50 164112 3.77 5.306 16.077 BS 678.00 168544 3.87 1.909 17.986 0.00 NP 678.50 175477 4.03 1.974 19.961 1.97 TS 680.00 183296 4.21 6.177 26.138 8.15 681.00 188578 4.33 4.269 30.407 12.42 WQv 682.00 193916 4.45 4.390 34.797 16.81 684.00 204761 4.70 9.152 43.949 25.96 686.00 215830 4.95 9.655 53.605 35.62 688.00 227123 5.21 10.169 63.774 45.79 690.00 238641 5.48 10.692 74.466 56.48 692.00 250383 5.75 11.226 85.693 67.71 Top Forebay Design Elevation Surface Area (sf) Area (ac-ft) Inc. Vol. (ac- ft) Total Vol. (ac-ft) % of Pool Volume Notes 674.00 5566 0.37 0.000 675.00 16191 0.64 0.250 0.250 1% 676.00 27988 0.90 0.507 0.757 4% 677.00 39214 0.96 0.771 1.528 9% 678.00 41815 0.00 0.930 2.458 16% Scour Hole Calculations Project Name: Greensboro -Randolph Megasite Project No. : Sheet Title : Pond A3 Originated By : Checked By: QA /QC Verification KET Date: Date: Date: November 10, 2021 Description Units Input Calculation Source Notes Q10 cfs 195 From HydroCAD pond routing Diameter Pipe inches 60 Design Manning's "n" 0.013 RCP Slope Pipe FT/FT 0.0048 Design Outlet Invert Elevation FT 670 Design Normal Depth FT 5 Pipe flowing full - see partial flow depth chart at right Velocity at Normal Depth fps 9.93 Tailwater Elevation FT 675 Assumed tailwater TW/D 1.00 Q/D^2.5 3.5 Yo/D 0.70 HEC 14, Figure III-10 Yo=Ye FT 3.5 Area at Ye FT2 13.51 From partial flow depth chart Velocity (V=Q/A) fps 14.43 RIP -RAP D50 FT 1.2 Class II D50/Ye 0.34 "FROUDE #" 1.36 hs/Ye 0.9 HEC 14, Figure X1-2 hs FT 3.15 Dispersion Pool Length FT 31.50 Apron Width FT 15.75 Depth of RIP -RAP Entrance Slope FT 3.60 Depth of RIP -RAP in Basin FT 2.40 1 2 3 4 5 6 7 8 INV 6I;; L�OU1ILET RQITECITION 1 i / / �/ ,\ J4 r /111\ (\ 1 +43.26 / '+00 / I I I1 / / 1 / / //J / 1 / 1 / / / / / // i \ 1 / \, 1 1 1 \ 1 1\ \ / / / ) 11 �_ // �l//// j i i I I /• i//// /,/ i i '� \\ )/`//// / // i /� L(/).,i/.4/{ / ///// y.� // //( I/ I IF0141 SURf AGE/ P EP/ 2/114;4 / / / BOTTOIyiIF1 S L / 1 \\JL 1�. II �# 1 I1\�\1 t 1 /1 I (j I.I il I/1/111 1 1 / 11/11r II 1' I //I/) // / // I�I( 1I ) / )(/ I I 1 )IJ , I I 1 / 11►'\I `111(/1)() 1/ IIII111 /1 II11 /1 Oip OFI R'IVj / J16 121 I // i)//1 /%/ 111 I // / / // 1 I\\ 11 �/ /I/ / 1 \\l / /)/\1 / / / // 1 l ( / / / / 1 ' / / / J / I ) / / /// // I'/ / / J / / / iy/ /// / 1 / /)/ / / / / ) / / / / ,/ // // ,'/� / // f / /( 1' 1 1 1 ' / \ -\- t 7/ \I / 1/ I 1 I lli I \ / 1 \ ( I 1 / 7 / / 1 / IN%/ 608( I I //// ))//// j I (( ( JJ l / I / /, 1 11 �/l(II / / // od / I I I I( I / / 1 / ; � / / lI / / // III / // I I —/// ) 1 / / /'/2/J // / / / J i / /I ( 1/ 7)/ r I // j //' J 1' - -/- / ///I / r f�I L jI / //// J /1 a\/// /)/ /// \ l / ////// / // / / "/ �// /// // ; /() / // / / / ' \ / // I/ / 1 // 1 J I J / 1 1 //// 1'//// / /// 7/,77 /l //////// / / /////// 77 / /„, / / -//// \ I / 1 /// // // / / / /(//// / % / / 1 (/ // I///II / // l 1 I // 1 / I) / 1l r �2 _ (I I/ l l 1 1 // \\� 1 \ ( ( ( i\~ • / / / ( I I 1 11 / —\ ( \�_ -- \. \ — N INV ) --� \ �� \ \ / I / I I \ \ \ \ \ \ \ 1 \ 1 7- (�\1\\I\ \\\\L (\ `\\�\ \ \ N. �( \�\\ 1 1 I I 1 I I l \ \ \\ \ \ \ \\ \\ \ ) -+- 1 / / , 1 1 1 1 I \ tea--�;��/ \ 1 /l� / 1\ 1 \ \ I \ \ ) j I Il I 11 l� /' , �� �' / //� 7 / �/ 7 / / /J // /l/ ) 1 I / \ \ / —e / / J 7 L ,/ /-� /, \\ \ \ / I l / / // 7 / / . i _J 660 650 640 630 620 610 600 590 CO .,'-1 111 3 IE = 608.00 r. Imo L o r H .e E0 T ______ O c~ii \ WATER QUALITY VOLUME EL 617 NORMAL P OL I EL 614 283 L F 11 11 MI 11• 11 11 11III 11 11•1 SEDIMENT STORAGE _ EL 608 I 644.84 644.5 639.55 638.3 it IIIII 644.47 643.9 643.90 642.(I Moo ai M coco 636.78 634.9 634.87 633.0 O 0�0 COM co �M N N N (o coco coco �N i� i N COCO ( O co r (D CO oi Ln d-co 0+00 0+50 1+00 1+50 2+00 2+50 3+00 3+50 4+00 4+50 5+00 5+50 6+00 6+50 7+00 7+50 8+00 8+50 660 650 640 630 620 610 600 590 9+00 HDR Engineering Inc. of the Carolinas 440 S. Church Street, Suite 1000 Charlotte, NC 28202 704.338.6700 N.C.B.E.L.S. License Number: F-0116 ISSUE DATE DESCRIPTION PROJECT MANAGER VICKIE M. MILLER, A1CP, PWS PROJECT ENGINEER DAVID BAKER, PE DESIGN ENGINEER WES TURLEY, PE DRAWN BY JENNIFER PALONI, EIT DRAWN BY JACOB RUDISILL CHECKED BY ROBERT BAYSDEN, PE PROJECT NUMBER 10068163 GREENSBORO RANDOLPH MEGASITE FOUNDATION GREENSBORO RANDOLPH MEGASITE RANDOLPH COUNTY, NORTH CAROLINA 0 1. STORMWATER EXHIBIT WET POND B2 2,, FILENAME SCALE SHEET Greensboro Megasite NC DEQ Wet Pond Analysis Wet Pond B2 Date: 10/26/2021 By: JP Rev: QC: KT Source: NCDEQ Stormwater Design Manual, C-3. Wet Pond - Apr7 2017 MDC 1-2 Main Pool Surface Area, Volume, and Depth Total Drainage Area to Pond (ac) = 279.00 Post -Developed Impervious Area (ac) = 177.90 Average Pool Depth Davg (ft) = 5.2 Pond Bottom Elevation (ft) = 608.00 Bottom of Sediment Storage Elevation (ft) = 607.00 Permanent Pool elevation (ft) = 614.00 Ratio (SAIDA) for Davg 1.55 Surface Area Required (ft2) 188375 Surface Area Provided (ft2) 214613 or 63.8 4.3245 acres Table 1: Piedmont and Mountain SAIDA Table % Permanent Pool Average Depth (ft) Impervious 3.0 4.0 5.0 6.0 7.0 8.0 10 0.51 0.43 0.37 0.30 0.27 0.25 20 0.84 0.69 0.61 0.51 0.44 0.40 30 1.17 0.94 0.84 0.72 0.61 0.56 40 1.51 1.24 1.09 0.91 0.78 0.71 50 1.79 1.51 1.31 1.13 0.95 0.87 60 2.09 1.77 1.49 1.31 1.12 1.03 70 2.51 2.09 1.80 1.56 1.34 1.17 72 2.51 2.09 1.80 1.56 1.34 1.17 80 2.92 2.41 2.07 1.82 1.62 1.40 90 3.25 2.64 2.31 2.04 1.84 1.59 100 3.55 2.79 2.52 2.34 2.04 1.75 Average Pond Depth VPP-Vshelf Abottomofshelf Where: D.,g = Average depth in feel Vpp = Total volume of permanent pool (feet') Vehalf = Volume over the shelf only (feet') - see below Abomomorshelf = Area of wet pond at the bottom of the shelf (feet2) Vaherr = Where: 0.5 • DBPthmax over shelf' Perimeter,,,, puq • Widthauhma coed pert or eheH Dma. core. shelf Perlmeterpama„ampod = Widthe„e,nemedpart weheH Depth of water at the deep side of the shelf as measured at permanent pool (feet) Perimeter of permanent pool at the bottom of the shelf (feel) Width from the deep side to the dry side of the shelf as measured at permanent peel (feet) Volume of Perm Pool VPP (ft3)= 1113926 Shelf Bottom Area Abot (ft3)= 211995 Max Pool Depth Above Shelf D. (ft)= 0.5 Perimeter of Shelf Bottom Pperm (ft)= 1874 Width of Submerged Shelf W sub (ft)= 3.0 Volume Over Shelf Vsheif (ft3)= 1406 Average Depth Davg (ft)= 5.25 Water Quality Volume Rv Where: DV Where: = 0.05 + 0.9 * (k Rv = Runoff coefficient (unitless) IA = Impervious fraction (unitless) 3630 * Rn * Rv * A DV Rn A = Design volume (cu ft) = Design storm depth (in) = Drainage area (ac) Runoff Coefficient Rv= 0.6 Design Storm Depth RD (in)= 1.0 Water Quality Volume (ft3)= 631838 Depth of Water Quality Volume Release (ft) 3.00 or 14.5 4.8 ac-ft acres Orifice Sizing WQv Stage in Pond (ft) 617.00 WQv Release Period (days) 4.0 WQv Release Rate (cfs) 1.83 Avg Head (ft) = (WQv Elev - Perm Pool Elev) 12 = 1.50 Estimated Orifice Diameter (in) 7.5 Orifice Diameter Provided (in) 7.0 Actual Release Rate (cfs) 1.58 Actual WQv Release Period (days) 4.6 Pond Grading Stage - Storage Data Elevation surtace Area (sf) Area (ac-ft) Inc. Vol. (ac- ft) lotal Vol. (ac-ft) !Jet. Vol. (ac- ft) Notes 608.00 148967 3.42 0.000 610.00 178807 4.10 7.525 7.525 612.00 195255 4.48 8.587 16.112 613.50 211995 4.87 7.012 23.124 BS 614.00 214613 4.93 2.448 25.572 0.00 NP 614.50 223363 5.13 2.514 28.086 2.51 TS 616.00 232041 5.33 7.841 35.927 10.35 617.00 237897 5.46 5.394 41.321 15.75 WQv 618.00 243810 5.60 5.529 46.850 21.28 620.00 255804 5.87 11.470 58.320 32.75 622.00 268025 6.15 12.025 70.345 44.77 Top Forebay Design Elevation Surface Area (sf) Area (ac-ft) Inc. Vol. (ac- ft) Total Vol. (ac-ft) % of Pool Volume Notes 608.00 12287 0.28 0.000 609.00 22118 0.51 0.395 0.395 2% 610.00 30448 0.70 0.603 0.998 4% 611.00 32660 0.75 0.724 1.723 7% 612.00 34945 0.80 0.776 2.499 11% 613.00 37303 0.86 0.829 3.328 15% 614.00 39734 0.91 0.884 4.212 20% Scour Hole Calculations Project Name: Greensboro -Randolph Megastie Project No. : Sheet Title : Pond B2 Originated By : Checked By: QA /QC Verification KET Date: Date: Date: November 15, 2021 Description Units Input Calculation Source Notes Q10 cfs 331 From HydroCAD pond routing Diameter Pipe inches 66 Design Manning's "n" 0.013 RCP Slope Pipe FT/FT 0.0143 Design Outlet Invert Elevation FT 604 Design Normal Depth FT 5.5 Pipe flowing full - see partial flow depth chart at right Velocity at Normal Depth fps 13.93 Tailwater Elevation FT 609 Assumed tailwater TW/D 0.91 Q/D^2.5 4.7 Yo/D 0.66 HEC 14, Figure III-10 Yo=Ye FT 3.63 Area at Ye FT2 16.3471 From partial flow depth chart Velocity (V=Q/A) fps 20.25 RIP -RAP D50 FT 1.2 Class II D50/Ye 0.33 "FROUDE #" 1.87 hs/Ye 0.7 HEC 14, Figure X1-2 hs FT 2.54 Dispersion Pool Length FT 25.41 Apron Width FT 12.71 Depth of RIP -RAP Entrance Slope FT 3.60 Depth of RIP -RAP in Basin FT 2.40 1 2 3 4 5 6 7 8 680 670 660 650 640 630 \\ \\ \\ \ \ \ \ \I G \\ \ \ l \\ \\ \\ \\\ \ \\ \ \ \ \I \ \ \\\\\\ \\ \\ \\\ \\\\�\\ \\\\\ \V654 \\ \ \ \ \\k \ \v I \ ) \ \\\ ( I ) \ \\\\\\ \: \ \\ \I i / \ \ \ \ f/ \\ \ \\ \\�\\ C \ / / // I ( I / / / 1 \ \ �\ \ / / 1 / I \ I ` \\ \\ _ 1 \\r �/ / % J I I / / 1 II l 1 1 / \) \\ ( / / /// /./ r / / j// 7 / 7 / / \ T-ePPOF SIH EJ F \II 1 EL 650,5 I I(E7RMAL-PeoL- — 1 €L-65.Q �SURFAAE€-4REA386•,k47 — 66-TTQ Ea! 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Church Street, Suite 1000 Charlotte, NC 28202 704.338.6700 N.C.B.E.L.S. License Number: F-0116 ISSUE DATE DESCRIPTION PROJECT MANAGER VICKIE M. MILLER, AICP, PWS PROJECT ENGINEER DAVID BAKER, PE DESIGN ENGINEER WES TURLEY, PE DRAWN BY JENNIFER PALONI, EIT DRAWN BY JACOB RUDISILL CHECKED BY ROBERT BAYSDEN, PE PROJECT NUMBER 10068163 GREENSBORO RANDOLPH MEGASITE FOUNDATION GREENSBORO RANDOLPH MEGASITE RANDOLPH COUNTY, NORTH CAROLINA 1" STORMWATER EXHIBIT WET POND C2 2- FILENAME SCALE SHEET Source: NCDEQ Stormwater Design Manual, C-3. Wet Pond - Apr7 2017 MDC 1-2 Main Pool Surface Area, Volume, and Depth Total Drainage Area to Pond (ac) = 533.80 Post -Developed Impervious Area (ac) = 325.30 Average Pool Depth Davg (ft) = 4.6 Pond Bottom Elevation (ft) = 644.00 Bottom of Sediment Storage Elevation (ft) = 643.00 Permanent Pool elevation (ft) = 650.00 Ratio (SAIDA) for Davg 1.49 Surface Area Required (ft2) 346460 Surface Area Provided (ft2) 386547 or 60.9 7.95362 acres Table 1: Piedmont and Mountain SAIDA Table % Permanent Pool Average Depth (ft) Impervious 3.0 4.0 5.0 6.0 7.0 8.0 10 0.51 0.43 0.37 0.30 0.27 0.25 20 0.84 0.69 0.61 0.51 0.44 0.40 30 1.17 0.94 0.84 0.72 0.61 0.56 40 1.51 1.24 1.09 0.91 0.78 0.71 50 1.79 1.51 1.31 1.13 0.95 0.87 60 2.09 1.77 1.49 1.31 1.12 1.03 70 2.51 2.09 1.80 1.56 1.34 1.17 72 2.59 2.15 1.85 1.61 1.40 1.22 80 2.92 2.41 2.07 1.82 1.62 1.40 90 3.25 2.64 2.31 2.04 1.84 1.59 100 3.55 2.79 2.52 2.34 2.04 1.75 % Average Pond Depth Dare = VPP-Vsheif Abottomofsheif Where: Deng Vehelf = Where: VPP Vehaa Anton of shelf 0.6 • Depth....., shell D. over shag Perimete rpem eeeel you Widths„emarged pan of aheff Average depth in feet. Total volume of permanent pool (feet3) Volume over the shelf only (feet3) - see below Area of wet pond at the bottom of the shelf (feet2) * Perimeterpe,,,, pow * Widthsubmerged part of shelf Depth of water at the deep side of the shelf as measured at permanent pool (feet) Perimeter of permanent pool at the bottom of the shelf (feet) Width from the deep side to the dry side of the shelf as measured at permanent pool (feet) Volume of Perm Pool Vpp (ft3)= 1763487 Shelf Bottom Area Abot (ft3)= 380777 Max Pool Depth Above Shelf Dmax (ft)= 0.5 Perimeter of Shelf Bottom Pprrm (ft)= 2417 Width of Submerged Shelf W sub (ft)= 3.0 Volume Over Shelf Vshelf (ft3)= 1813 Average Depth Dag (ft)= 4.63 Water Quality Volume Where_ 0.05 + 0.9*IA Rv IA Runoff coefficient (unitless) Impervious fraction (unitless) DV = 3630* RD*Rv*A Where: DV Re Design volume (cu ft) Design storm depth (in) Drainage area (ac) Runoff Coefficient Rv= 0.6 Design Storm Depth RD (in)= 1.0 Water Quality Volume (ft3)= 1159640 Depth of Water Quality Volume Release (ft) 3.00 or 26.6 8.9 ac-ft acres Orifice Sizing WQv Stage in Pond (ft) 653.00 WQv Release Period (days) 4.0 WQv Release Rate (cfs) 3.36 Avg Head (ft) = (WQv Elev - Perm Pool Elev) 12 = 1.50 Estimated Orifice Diameter (in) 10.2 Orifice Diameter Provided (in) 10.0 Actual Release Rate (cfs) 3.22 Actual WQv Release Period (days) 4.2 Stage - Storage Data Elevation surtace Area (sf) Area (ac-ft) Inc. Vol. (ac- ft) Iotal Vol. (ac-ft) !Jet. Vol. (ac- ft) Notes 644.00 223281 5.13 0.000 646.00 260873 5.99 11.115 11.115 648.00 309169 7.10 13.086 24.201 649.50 380777 8.74 11.879 36.080 BS 650.00 386547 8.87 4.404 40.484 0.00 NP 650.50 395416 9.08 4.488 44.972 4.49 TS 652.00 406548 9.33 13.808 58.780 18.30 653.00 414041 9.51 9.419 68.199 27.71 WQv 654.00 421590 9.68 9.592 77.791 37.31 656.00 436857 10.03 19.707 97.498 57.01 657.50 448455 10.30 15.243 112.741 72.26 Top Forebay Design Elevation Surface Area (sf) Area (ac-ft) Inc. Vol. (ac- ft) Total Vol. (ac-ft) % of Pool Volume Notes 644.00 6348 0.15 0.000 645.00 19104 0.44 0.292 0.292 1% 646.00 33452 0.77 0.603 0.895 2% 647.00 45890 1.05 0.911 1.806 5% 648.00 71058 1.63 1.342 3.149 8% 649.00 74435 1.71 1.670 4.819 14% 650.00 77890 1.79 1.748 6.567 19% Scour Hole Calculations Project Name: Greensboro -Randolph Megastie Project No. : Sheet Title : Pond C2 Originated By : Checked By: QA /QC Verification KET Date: Date: Date: November 10, 2021 Description Units Input Calculation Source Notes Q10 cfs 364 From HydroCAD pond routing Diameter Pipe inches 72 Design Manning's "n" 0.013 RCP Slope Pipe FT/FT 0.0425 Design Outlet Invert Elevation FT 626 Design Normal Depth FT 6 Pipe flowing full - see partial flow depth chart at right Velocity at Normal Depth fps #REF! Tailwater Elevation FT 632 Assumed tailwater TW/D 1.00 Q/D^2.5 4.1 Yo/D 0.70 HEC 14, Figure III-10 Yo=Ye FT 4.2 Area at Ye FT2 19.4544 From partial flow depth chart Velocity (V=Q/A) fps 18.71 RIP -RAP D50 FT 1.2 Class II D50/Ye 0.29 "FROUDE #" 1.61 hs/Ye 1.5 HEC 14, Figure X1-2 hs FT 6.30 Dispersion Pool Length FT 63.00 Apron Width FT 31.50 Depth of RIP -RAP Entrance Slope FT 3.60 Depth of RIP -RAP in Basin FT 2.40 1 2 3 4 5 6 7 8 HDR Engineering Inc. of the Carolinas 440 S. Church Street, Suite 1000 Charlotte, NC 28202 704.338.6700 N.C.B.E.L.S. License Number: F-0116 ISSUE DATE DESCRIPTION PROJECT MANAGER VICKIE M. MILLER, AICP, PWS PROJECT ENGINEER DAVID BAKER, PE DESIGN ENGINEER WES TURLEY, PE DRAWN BY JENNIFER PALONI, EIT DRAWN BY JACOB RUDISILL CHECKED BY ROBERT BAYSDEN, PE PROJECT NUMBER 10068163 GREENSBORO RANDOLPH MEGASITE FOUNDATION GREENSBORO RANDOLPH MEGASITE RANDOLPH COUNTY, NORTH CAROLINA 0 1" STORMWATER EXHIBIT DRY PONDS 2,, FILENAME SCALE 01 C-BG01-08.dwg 1"=150' SHEET STORMWATER MANAGEMENT PLAN GREENSBORO-RANDOLPH MEAGASITE Appendix E — Proposed Condition Model Results 6 I November 15, 2021 DA Al <Subca> (A1 (A2 Al Pon A3 1— A-1 Outfall Al Reach A2 DA A2 A-2 Outfall A2 (B2.0 DA B2 B Pond B1 A Pon B1 B2 B-1 Total DA B DA 63. U B-2 Outfall B2 Total DA C Routing Diagram for ProposedConditions 11.10.21 Prepared by HDR, Inc, Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 2 Area Listing (all nodes) Area CN Description (acres) (subcatchment-numbers) 99.300 94 (A1) 404.100 95 (A2, B1) 53.900 76 (A3.U) 37.000 78 (A4.U) 33.500 73 (B2.U) 62.000 69 (B3.U) 533.800 91 (C1) 183.000 75 (C2.U) 162.400 72 (C3.U) 1,569.000 86 TOTAL AREA ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 3 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.000 HSG A 0.000 HSG B 0.000 HSG C 0.000 HSG D 1,569.000 Other Al, A2, A3.U, A4.U, B1, B2.U, B3.U, C1, C2.U, C3.0 1,569.000 TOTAL AREA ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 4 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 0.000 0.000 0.000 0.000 0.000 0.000 1,569.000 1,569.000 Al , A2, A3.U, A4.U, B1, B2.U, B3.U, C1, C2.U, C3.0 0.000 1,569.000 1,569.000 TOTAL AREA ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Printed 11/15/2021 Page 5 Pipe Listing (all nodes) Line# Node In -Invert Out -Invert Length Slope n Diam/Width Height Inside -Fill Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) 1 Pond A3 2 Pond B1 3 Pond B2 4 Pond C1 5 Pond C2 672.00 676.00 608.00 665.00 644.00 670.00 617.00 604.00 654.00 626.00 414.0 711.0 280.0 991.0 424.0 0.0048 0.0830 0.0143 0.0111 0.0425 0.013 0.013 0.013 0.013 0.013 60.0 84.0 66.0 72.0 72.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 6 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentAl: Al -A SubcatchmentA2: A2 SubcatchmentA3.U: DAA1 SubcatchmentA4.U: DA A2 SubcatchmentBl: B1-A SubcatchmentB2.U: DA B2.0 SubcatchmentB3.U: DA B3.0 SubcatchmentCl: C1-A SubcatchmentC2.U: DA C2.0 SubcatchmentC3.U: DA C3.0 Pond Pond A3: Pond A3 RunoffArea=99.300 ac 0.00% Impervious Runoff Depth=6.71" Tc=20.0 min CN=94 Runoff=549.10 cfs 55.487 af Runoff Area=125.300 ac 0.00% Impervious Runoff Depth=6.82" Tc=25.0 min CN=95 Runoff=629.70 cfs 71.251 af RunoffArea=53.900 ac 0.00% Impervious Runoff Depth=4.63" Tc=30.0 min CN=76 Runoff=184.14 cfs 20.811 af RunoffArea=37.000 ac 0.00% Impervious Runoff Depth=4.86" Tc=22.0 min CN=78 Runoff=154.43 cfs 14.977 af RunoffArea=278.800 ac 0.00% Impervious Runoff Depth=6.82" Tc=30.0 min CN=95 Runoff=1,275.64 cfs 158.538 af RunoffArea=33.500 ac 0.00% Impervious Runoff Depth=4.30" Tc=30.0 min CN=73 Runoff=106.37 cfs 12.003 af RunoffArea=62.000 ac 0.00% Impervious Runoff Depth=3.86" Tc=30.0 min CN=69 Runoff=176.58 cfs 19.950 af RunoffArea=533.800 ac 0.00% Impervious Runoff Depth=6.35" Tc=30.0 min CN=91 Runoff=2,356.30 cfs 282.572 af Runoff Area=183.000 ac 0.00% Impervious Runoff Depth=4.52" Tc=50.0 min CN=75 Runoff=457.89 cfs 68.954 af Runoff Area=162.400 ac 0.00% Impervious Runoff Depth=4.19" Tc=45.0 min CN=72 Runoff=402.29 cfs 56.697 af Peak EIev=690.31' Storage=3,314,277 cf Inflow=1,164.50 cfs 126.739 af Outflow=354.77 cfs 116.715 af Pond Pond B1: Pond B1 Peak EIev=686.46' Storage=2,157,866 cf Inflow=1,275.64 cfs 158.538 af 84.0" Round Culvert n=0.013 L=711.0' S=0.0830 '/' Outflow=489.01 cfs 158.426 af Pond Pond B2: Pond B2 Peak EIev=620.97' Storage=2,782,860 cf Inflow=489.01 cfs 158.426 af Outflow=365.70 cfs 145.363 af Pond Pond C1: Pond C1 Peak EIev=681.15' Storage=5,401,245 cf Inflow=2,356.30 cfs 282.572 af 72.0" Round Culvert n=0.013 L=991.0' S=0.0111 '/' Outflow=518.18 cfs 280.511 af Pond Pond C2: Pond C2 Peak EIev=656.72' Storage=4,545,124 cf Inflow=518.18 cfs 280.511 af Outflow=424.39 cfs 257.423 af Link A-1: Outfall A1 Inflow=530.21 cfs 137.525 af Primary=530.21 cfs 137.525 af ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 7 Link A-2: Outfall A2 Link B-1: Total DA B Link B-2: Outfall B2 Link C: Total DA C Inflow=154.43 cfs 14.977 af Primary=154.43 cfs 14.977 af Inflow=415.71 cfs 157.366 af Primary=415.71 cfs 157.366 af Inflow=176.58 cfs 19.950 af Primary=176.58 cfs 19.950 af Inflow=1,143.62 cfs 383.074 af Primary=1,143.62 cfs 383.074 af Total Runoff Area = 1,569.000 ac Runoff Volume = 761.241 af Average Runoff Depth = 5.82" 100.00% Pervious = 1,569.000 ac 0.00% Impervious = 0.000 ac ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment Al: Al -A Runoff = 549.10 cfs @ 12.29 hrs, Volume= 55.487 af, Depth= 6.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description 99.300 94 99.300 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 20.0 600- 550- 500 450— Direct Entry, Subcatchment Al: Al -A Hydrograph 400- 350— 300— 250J k 200— 1501 100 50- 1549.10 cfs J T T T T T T T 7 T 7 J J r N RCq-1 QOyr-24hr NRCC rt 24-hrIB Rai;nf0=7.4" Flunoff Area=9-$ 300-ic- RI.tn-of#-VoFktme=55. 7 #- Runo f Depth=6.71" T T T T J T J Tc=O.9 min CiV=94 i 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment A2: A2 Runoff = 629.70 cfs @ 12.35 hrs, Volume= 71.251 af, Depth= 6.82" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description * 125.300 95 125.300 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 25.0 Direct Entry, 0 LL Subcatchment A2: A2 Hydrograph 700- 650- 600:- 550- 5001- 450J 4001- 350- 300� 250� 200- L 150- 100: 50J + + + + + - + r 1629.70 cfs T 0 r L L i -1 -L 4- ✓ 8 10 12 4 ✓ r r r ,L [► y� y,� p IY REC 24 11 3 -N Rcq-100yr 24h r Ra-nf01=y:4;" - Ruh oft A-rea-125,300-ic- + rr t R>.rnc ff VoFvm=7'i.25 L f- Runoff Depth=6.82" Tc=5.9 min + CN=95 ✓ ✓ r r L ✓ /����t L L r 1 i i 14 16 18 20 22 24 26 28 30 Time (hours) 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 ©2019 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment A3.U: DA Al Runoff = 184.14 cfs @ 12.42 hrs, Volume= 20.811 af, Depth= 4.63" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description 53.900 76 53.900 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Subcatchment A3.U: DA Al Hydrograph 200'' 190� 180J 160 150=- 140� k 130= k 120� fi ▪ 110'" 3 LT_ 90J 80= 70= 60- 50= 40� 30�fi 20_ - 1 0- ' 0 ✓ r r 184.14 cfs ✓ 1 1 r T + r T t ▪ r ▪ T t r ri NRCC 24'1-hrlB ▪ r t r -NRC -1QOyr 2-4hrRaMn#ajll='�.4 Runo Arei=5 900-ac- Runoff Vol tome=20.8,11 ;f ▪ Runoff -Depth=4.6 "- Tc=1O 9 min - ▪ r r T 7 T CN=76 4 4 1 + t T T T r l r T r 4 1 4 + r r t 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff T r 1154.43 cf I J t J ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment A4.U: DA A2 Runoff = 154.43 cfs @ 12.32 hrs, Volume= 14.977 af, Depth= 4.86" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description 37.000 78 37.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 22.0 Direct Entry, 170_ r 160- 150� 140/ 130 ' 120� 1 110� 80J t J J v r J J Subcatchment A4.U: DA A2 J t J t J Hydrograph J r r r 1 N Rcq-1 QOyr-24hr NRCC 24.hrIB RaMnf0=7.4r Runoff Area=37.000 ac Run_Off VoF�in 114.Srt7-7- f- ▪ J Runoff-Depth=4, 86" - Tc=;2:9-m n- C 4=78- t r r J J J ll�(lll�lll� 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment B1: B1-A Runoff = 1,275.64 cfs @ 12.41 hrs, Volume= 158.538 af, Depth= 6.82" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description * 278.800 95 278.800 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, 0 LL Subcatchment B1: B1-A Hydrograph 1,40/ 1,0007- 900 - 800- 7007- 600J 500 4007- 11 3001' 200 100� 0 i L I i 11,275.64 cf 4- t i ✓ J 1 + ✓ 1 L + NRCC 24rhriB- _NRCC -'1100y .2-4hr-Rainfall=7t4r L urioff_4rea,27$ 840_ic _ Runoff Volume=1510.5138 1f Runoff Depth=6.82" r i i r Tp=QO.Q min CNV=95 + 1 1 1 L r r t 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment B2.U: DA B2.0 Runoff = 106.37 cfs @ 12.43 hrs, Volume= 12.003 af, Depth= 4.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description 33.500 73 33.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Subcatchment B2.U: DA B2.0 Hydrograph 115.-zT 110 ▪ 41 7 7 Ti L r 1 1 i 106.37 c 105- k-------+ + + 100-7:' 1 1 1 95 ' 1 1 A 1 L 9ofi rt + 85� 1 80- )1-1 1 1 r 75 ' 1 I ; r r 70� 1 1.N U 65� k--r--i---- 60= 7 1 1, 7 T 0 55J LL 50 fi I 1 y--rt--+ 45— ' 40- 1 1 A 1 L 35 r r r 30 25 k 1 1 1 1 r 20 r 7 7 T 15 ' ' 10 A-1 i + -+ 5 1 0 7 J 4 7 1 4- 1 1- 1 1 1 L 1 7 L 1- r L 4 1 4- 1 +--+- + + +--+--1 R'C-C124hr+B- ▪ 1 + r -NR-cp=190yr=2-4hr='F�aMnfialll= 4;" 1 1 1 L 1 1 r Rtanoff-Area=3 5bQac- R nc fflitofymp=T112.* of- r Rta noff-Depth=4:30" - Tc=p0.Q min 7 7 T r 1 1, r r 1 1 CN=73 + - - + 1 1 1 y - - t - - r 1 1 1 rt - - + ▪ 1 1 - L 1 1 1 L r L 1 1 1 1 1 ✓ r r r I I I 1 r r 1 I I r r 1 1 1 L 1 1 1 -4 1 T 1 1 1 1 1 7 7 T r 1 1 1 7 T r 1 1 1 T T 4+ + - - r - - r + — — + — — 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment B3.U: DA B3.0 Runoff = 176.58 cfs @ 12.43 hrs, Volume= 19.950 af, Depth= 3.86" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description 62.000 69 62.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Subcatchment B3.U: DA B3.0 Hydrograph L L 190=�� 1 1 r L 1176.58 cfs 180� z ) 1 1 170� ,L li 160- ,_ 150'' 11L 1 140= k 130� T 1� 120=�EfL4 w 110� k di 100 3 1 + + agir LL 90 = 1 1 r r t = 80=-' 1 r Iii70= r t t t 60- - t t 50 T 1 1 T T 40 1 1 1 1 1 T T 30 T 1 1 r 20= z. I J 10= L L L L L L r L1 Runoff Area= 62,O00-�c- 1 RI.mpff VoF4tmY=19. f- t T r 0 2 4 6 8 10 12 14 16 1 1 1 - T L 1 1 1 1 r 1 1 r r NRCC 24-h r B N Rcq-1 QOyr-24hr 1Ranfal110.4 " r 1RunoTDepth= .8b" r + Tc=p0.9 min + r Cg=89 ▪ t t r 1 1 1 t r r 1 1 1 t t ✓ r r r 11 11 11 r r r 11 11 11 r r t t t Y 1 1 1 t 1- r 1 1 1 t t t T t r 1 1 1 t r r 1 1 1 T T T T T T 1 1 1 T T T 1 1 1 T T 1 T T r 1 1 1 1 r r i i 1 T T 1 T T r 1 1 1 1 r r 1 1 1 T T 1 T T r 1 1 1 1 T r i i 1 T T 18 20 22 24 26 Time (hours) 28 30 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment C1: C1-A Runoff = 2,356.30 cfs @ 12.41 hrs, Volume= 282.572 af, Depth= 6.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description * 533.800 91 533.800 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Subcatchment C1: C1-A Hydrograph 2,600- T 2,500 -h 2,4004- 2,300 -h 2,2004- 2,1007,E 2,000/ r 1,900= r 1,800 I 1 1 L I L 1 L L 1 L I I 1 1 L I I 1 1 L I L 2,356.30 cfs 1 1 1 1 1 1 NR'Ct 24shr1B - 7 T / -1 T r ItRIpC=r010y=2411. r R-ai�Inf;�11=T-4;" I 1 L L i_1 1 L I L 1 1 ✓ I L I I 7 T I 1 L ✓ I L I 1 1 i i--i--+ 1,7007;',H 1 + + 1,600+ Air + 1,500" 1 + + + O 1,4004' 1,300+;" 1 4 + 0 1,200= u` 1,100� 1,000= 900- fi 800 700 600 500 400 300 200 100 0 T t T + I 0 APII 7 T 'r r 7 + r 7 T r 7 + r I1111 7 r I I 1 1 L J IIII IIII I I e 0 1I L LI 1 L L L L I 1I 1 1 1 r4 7 1 L 1 1 L 1 1 L 1 1 Ftrrroff'I Area53 8b0-ec - + + + I I + + + I I 4 + -Runoff Vglu-meag•-572 I I- 1Run off Depth + + I CNMt- ✓ Y r I I r t Y I I r r r I I r t k I I 4 r r I I L r L I I L 1 L I I 4 r 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 16 Summary for Subcatchment C2.U: DA C2.0 Runoff = 457.89 cfs @ 12.68 hrs, Volume= 68.954 af, Depth= 4.52" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description * 183.000 75 183.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 50.0 Direct Entry, Subcatchment C2.U: DA C2.0 Hydrograph 1 7 7 T r 500+ L L 1 L 4807;'" i 1-[ 7 1 457.89 c 460 ) L L L 440� r i i , 7 r 420� / L L L 4007:" • r i i -r-r r 380 3601 1 7 7 r � 340+2, ,2- ' ' ' 320� • - i 1 +--7--+ 300 13 w 280� 2+ 1 1 + 7 + 260 0 240° A- -I + -+ a 220�� 1 1 I I 200° + +----+ + -+ 180= 1 1 160= / 1 1 1--+--+ 140= 1 1 120' �+ 1 1 - 7 + 100"• 1 , 80° k 60- ; 0 2 4 6 8 10 12 si 7 7 T T 1 I 1 7 T r I I 1 7 T • L L L i i i L L L i i i L L 7 7 T T 1 I 1 7 T ▪ 1 L L1111 1 1 1 ▪ L NR'CCI 24�t1 riB 7 r r i r 1 1 1 7 T 7 r r 1 1 1 7 T ▪ 1 L NRcq-4p0yr 24hrRainfalll=T4;"- I▪ I▪ I▪ I▪ Ifturiof$Ar'ea18.0c9_ic_ ▪ T T r 1 Rcffoilirrre=66.9;54 f - - - +R off -Depth= :5 "- + + + + Tc= OQrnn_ 11111 11111 c1 =75 + + + + 1 + + + 1 + + + + + + 1 + + + 1 + + • + + + +--+ 1 1 1 1 1 1 1 1 1 4 + + , 1 + 4 + + I I 1 + + + I I 1 4 + 14 16 18 20 22 24 26 Time (hours) 28 30 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment C3.U: DA C3.0 Runoff = 402.29 cfs @ 12.62 hrs, Volume= 56.697 af, Depth= 4.19" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Area (ac) CN Description * 162.400 72 162.400 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 45.0 Direct Entry, Subcatchment C3.U: DA C3.0 Hydrograph 440_ 420� )— I - 41 1 a02.29 o 400� T LI 32O -' r r r 300�zz,B 280'=" 1 26O ' ,r T T T 240i" I 1 220i" 1 1 200� z k 41 4 r 1 160'=" f::ijii 1007--' T II II II II II II II II II II II II II II 80"" 40= r + + + + + r + + r + + 1 1 T A- 1 1 1 4 4 4 1 1 1 4 + r 1 r r r R'CCI24rfit'rB- N CCU=?QOyr=Z4hr=RaMnfoll= 4;"- 11 kith oft Are a1 &, 4 0D- c - noff-Vorym=56.6a7- f- 11 TI tRoff-Depth=4,19"- Tc=4t9- 1 1 - 1 L 1 1 1 1 1 1 T T r 1 1 1 1 r r 1 1 1 T T 0 i • 8 10 12 14 16 18 20 22 24 26 28 30 Time (hours) /// 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 18 Summary for Pond Pond A3: Pond A3 Inflow Area = 224.600 ac, 0.00% Impervious, Inflow Depth = 6.77" for NRCC-100yr-24hr event Inflow = 1,164.50 cfs @ 12.31 hrs, Volume= 126.739 of Outflow = 354.77 cfs @ 12.81 hrs, Volume= 116.715 af, Atten= 70%, Lag= 29.7 min Primary = 354.77 cfs @ 12.81 hrs, Volume= 116.715 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 678.00' Surf.Area= 168,544 sf Storage= 781,799 cf Peak Elev= 690.31' @ 12.81 hrs Surf.Area= 240,490 sf Storage= 3,314,277 cf (2,532,478 cf above start) Plug -Flow detention time= 270.1 min calculated for 98.767 af (78% of inflow) Center -of -Mass det. time= 149.6 min (926.5 - 776.8 ) Volume Invert Avail.Storage Storage Description #1 Elevation (feet) 672.00 674.00 676.00 678.00 680.00 682.00 684.00 686.00 688.00 690.00 692.00 672.00' 3,727,860 cf Custom Stage Data (Prismatic)Listed below (Recalc) Device Routing Surf.Area (sq-ft) 99,117 113,009 144,060 168,544 183,296 193,916 204,761 215,830 227,123 238,641 250,383 Invert Inc.Store (cubic -feet) 0 212,126 257,069 312,604 351,840 377,212 398,677 420,591 442,953 465,764 489,024 Outlet Devices Cum.Store (cubic -feet) 0 212,126 469,195 781,799 1,133,639 1,510,851 1,909,528 2,330,119 2,773,072 3,238,836 3,727,860 #1 Primary #2 #3 #4 Device 1 Device 1 Device 1 672.00' 678.00' 688.00' 681.00' 60.0" Round Culvert L= 414.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 672.00' / 670.00' S= 0.0048'/' Cc= 0.900 n= 0.013, Flow Area= 19.63 sf 6.0" Vert. Orifice/Grate C= 0.600 40.0' long Sharp -Crested Rectangular Weir 0 End Contraction(s) 54.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=354.74 cfs @ 12.81 hrs HW=690.31' (Free Discharge) 4-1=Culvert (Barrel Controls 354.74 cfs @ 18.07 fps) - 2=Orifice/Grate (Passes < 3.28 cfs potential flow) - 3=Sharp-Crested Rectangular Weir(Passes < 459.92 cfs potential flow) -4=Orifice/Grate (Passes < 233.69 cfs potential flow) ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 19 Pond Pond A3: Pond A3 Hyd rog raph ✓ t r i 1,300-` 1,2007:- 1,1007- 1,0007:� 900:- L 800J ' 700: /r 600- / r LL 400: 300- 200- 100 Elevation (feet) 1,164.50 1 J r 354.77 cfs J J ▪ r t ✓ r J r J J 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hours) 692/ 691J 690� 689J 688� 687J 686� 685J 684=- 683� 682� 681 680 679 II II II II II Inflow A$a=324:6100-a-c- Peak t1ev=69O.311 J J J J J StorageJ=3,314,277 cf t r ▪ r 1 1 1 J (n Try\ T Irrn T rrn1r,i 1 T r(n1.)i Ilrr. 1 28 30 32 34 36 38 40 42 44 46 48 Pond Pond A3: Pond A3 Stage -Discharge ✓ r Shjp-Crested Rectangular Weir 1 L �ii�L L L L L L Orifice/Grp L - Orifice/Grate 678 677�� 676 675 674 673J 672 . . 0 50 100 J J ✓ r ✓ r J J t t J J r r t t i---- r r - r r - t t - 150 200 250 300 350 Discharge (cfs) r C Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 20 692-' 691� 690 689J 688 687 686 685 684 683 0 682J 681 w 680- w 679 678 677 676= 675- 674� 673 672 Pond Pond A3: Pond A3 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 200,000 220,000 240,000 I'''I 'III I'''I'II II ri I J L ll11 J I L- -- H ----+---I-� r----a—---�— --t ��Vt---- I J L ll _I/// IL IL Ir i JI r I-4 -4 I r I r I I r n r I I r r rI Custom Stage Data 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000 3,500,000 Storage (cubic -feet) u Surface • Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 21 Stage -Discharge for Pond Pond A3: Pond A3 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 672.00 0.00 682.40 78.50 672.20 0.00 682.60 95.53 672.40 0.00 682.80 104.76 672.60 0.00 683.00 110.36 672.80 0.00 683.20 115.69 673.00 0.00 683.40 120.78 673.20 0.00 683.60 125.67 673.40 0.00 683.80 130.37 673.60 0.00 684.00 134.91 673.80 0.00 684.20 139.29 674.00 0.00 684.40 143.55 674.20 0.00 684.60 147.68 674.40 0.00 684.80 151.70 674.60 0.00 685.00 155.61 674.80 0.00 685.20 159.43 675.00 0.00 685.40 163.16 675.20 0.00 685.60 166.81 675.40 0.00 685.80 170.37 675.60 0.00 686.00 173.87 675.80 0.00 686.20 177.29 676.00 0.00 686.40 180.65 676.20 0.00 686.60 183.95 676.40 0.00 686.80 187.19 676.60 0.00 687.00 190.38 676.80 0.00 687.20 193.51 677.00 0.00 687.40 196.59 677.20 0.00 687.60 199.63 677.40 0.00 687.80 202.61 677.60 0.00 688.00 205.56 677.80 0.00 688.20 220.16 678.00 0.00 688.40 244.42 678.20 0.11 688.60 274.95 678.40 0.36 688.80 310.54 678.60 0.56 689.00 339.20 678.80 0.70 689.20 341.61 679.00 0.82 689.40 344.01 679.20 0.92 689.60 346.39 679.40 1.01 689.80 348.75 679.60 1.10 690.00 351.10 679.80 1.18 690.20 353.43 680.00 1.25 690.40 355.75 680.20 1.32 690.60 358.05 680.40 1.39 690.80 360.34 680.60 1.45 691.00 362.62 680.80 1.51 691.20 364.88 681.00 1.57 691.40 367.12 681.20 5.76 691.60 369.35 681.40 13.37 691.80 371.57 681.60 23.22 692.00 373.78 681.80 34.86 682.00 48.06 682.20 62.65 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 22 Stage -Area -Storage for Pond Pond A3: Pond A3 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 672.00 99,117 0 682.40 196,085 1,588,851 672.20 100,506 19,962 682.60 197,170 1,628,177 672.40 101,895 40,202 682.80 198,254 1,667,719 672.60 103,285 60,720 683.00 199,339 1,707,478 672.80 104,674 81,516 683.20 200,423 1,747,454 673.00 106,063 102,590 683.40 201,507 1,787,647 673.20 107,452 123,942 683.60 202,592 1,828,057 673.40 108,841 145,571 683.80 203,676 1,868,684 673.60 110,231 167,478 684.00 204,761 1,909,528 673.80 111,620 189,663 684.20 205,868 1,950,591 674.00 113,009 212,126 684.40 206,975 1,991,875 674.20 116,114 235,038 684.60 208,082 2,033,381 674.40 119,219 258,572 684.80 209,189 2,075,108 674.60 122,324 282,726 685.00 210,296 2,117,056 674.80 125,429 307,501 685.20 211,402 2,159,226 675.00 128,535 332,898 685.40 212,509 2,201,617 675.20 131,640 358,915 685.60 213,616 2,244,230 675.40 134,745 385,554 685.80 214,723 2,287,064 675.60 137,850 412,813 686.00 215,830 2,330,119 675.80 140,955 440,694 686.20 216,959 2,373,398 676.00 144,060 469,195 686.40 218,089 2,416,903 676.20 146,508 498,252 686.60 219,218 2,460,633 676.40 148,957 527,798 686.80 220,347 2,504,590 676.60 151,405 557,835 687.00 221,477 2,548,772 676.80 153,854 588,360 687.20 222,606 2,593,180 677.00 156,302 619,376 687.40 223,735 2,637,815 677.20 158,750 650,881 687.60 224,864 2,682,675 677.40 161,199 682,876 687.80 225,994 2,727,760 677.60 163,647 715,361 688.00 227,123 2,773,072 677.80 166,096 748,335 688.20 228,275 2,818,612 678.00 168,544 781,799 688.40 229,427 2,864,382 678.20 170,019 815,655 688.60 230,578 2,910,382 678.40 171,494 849,807 688.80 231,730 2,956,613 678.60 172,970 884,253 689.00 232,882 3,003,075 678.80 174,445 918,995 689.20 234,034 3,049,766 679.00 175,920 954,031 689.40 235,186 3,096,688 679.20 177,395 989,363 689.60 236,337 3,143,840 679.40 178,870 1,024,989 689.80 237,489 3,191,223 679.60 180,346 1,060,911 690.00 238,641 3,238,836 679.80 181,821 1,097,127 690.20 239,815 3,286,682 680.00 183,296 1,133,639 690.40 240,989 3,334,762 680.20 184,358 1,170,404 690.60 242,164 3,383,077 680.40 185,420 1,207,382 690.80 243,338 3,431,628 680.60 186,482 1,244,572 691.00 244,512 3,480,413 680.80 187,544 1,281,975 691.20 245,686 3,529,432 681.00 188,606 1,319,590 691.40 246,860 3,578,687 681.20 189,668 1,357,417 691.60 248,035 3,628,176 681.40 190,730 1,395,457 691.80 249,209 3,677,901 681.60 191,792 1,433,709 692.00 250,383 3,727,860 681.80 192,854 1,472,174 682.00 193,916 1,510,851 682.20 195,001 1,549,743 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 23 Summary for Pond Pond B1: Pond B1 Inflow Area = 278.800 ac, 0.00% Impervious, Inflow Depth = 6.82" for NRCC-100yr-24hr event Inflow = 1,275.64 cfs @ 12.41 hrs, Volume= 158.538 of Outflow = 489.01 cfs @ 12.90 hrs, Volume= 158.426 af, Atten= 62%, Lag= 29.4 min Primary = 489.01 cfs @ 12.90 hrs, Volume= 158.426 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 686.46' @ 12.90 hrs Surf.Area= 353,105 sf Storage= 2,157,866 cf Plug -Flow detention time= 67.4 min calculated for 158.261 af (100% of inflow) Center -of -Mass det. time= 67.8 min (849.4 - 781.6 ) Volume Invert Avail.Storage Storage Description #1 676.00' 2,737,543 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 676.00 75,404 0 0 678.00 120,832 196,236 196,236 680.00 169,974 290,806 487,042 682.00 222,421 392,395 879,437 684.00 278,551 500,972 1,380,409 686.00 338,363 616,914 1,997,323 688.00 401,857 740,220 2,737,543 Device Routing Invert Outlet Devices #1 Primary 676.00' 84.0" Round Culvert L= 711.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 676.00' / 617.00' S= 0.0830'/' Cc= 0.900 n= 0.013, Flow Area= 38.48 sf Primary OutFlow Max=488.99 cfs @ 12.90 hrs HW=686.46' (Free Discharge) 4-1=Culvert (Inlet Controls 488.99 cfs @ 12.71 fps) ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 24 Pond Pond B1: Pond B1 Hyd rog raph 1,400- L 1,200� z 'I 1,100�� 1,000�� 1 ▪ 800: 700� z /1 • 600- ',+ 5007 400� 300-1" 200: �'1 1002 Elevation (feet) 0 688- 687J 686—/ 685J T 684— 683� 682� 681-' 680- 679- z = k 678—' 677- 676 I 1,2▪ 75.64 cfs + I 489.01 cfs 0 „, :._ , 0, , , 1n-flow1140a=378:8-O0'� a-e- 1 Peak t1eLv=s86.46'- sto r�►ge=2,157,866 cif ▪ key rid Culvert n=0.018 L'�=711.0' s=01.O83O-'1' r T r 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time (hours) Ti i Pond Pond B1: Pond B1 Stage -Discharge 1 + 1 1 + 1 ✓ + L ✓ L + 4- Ti 1 0 50 100 150 200 250 300 Discharge (cfs) 1 + 1 1 + + ✓ + L + L + r 46 r T L 1 1 -4 350 400 450 500 48 / 1 Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 688 687J 686- 6851- 684- w 6831' I682Y - 681:� w 680- 6791" 678 677- Pond Pond B1: Pond B1 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft, 50,000 100,000 150,000 200,000 250,000 300,000 350,000 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 25 400,000 T 4 Custom Stage Dati 676 0 500,000 1,000,000 1,500,000 Storage (cubic -feet) 2,000,000 2,500,000 • Surface` • Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 26 Stage -Discharge for Pond Pond B1: Pond B1 Elevation Primary Elevation Primary Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) (feet) (cfs) (feet) (cfs) 676.00 0.00 679.12 99.76 682.24 308.09 685.36 448.57 676.06 0.04 679.18 103.25 682.30 311.76 685.42 450.86 676.12 0.17 679.24 106.78 682.36 315.37 685.48 453.14 676.18 0.39 679.30 110.36 682.42 318.89 685.54 455.41 676.24 0.68 679.36 113.97 682.48 322.34 685.60 457.66 676.30 1.07 679.42 117.63 682.54 325.69 685.66 459.91 676.36 1.53 679.48 121.33 682.60 328.95 685.72 462.14 676.42 2.08 679.54 125.06 682.66 332.09 685.78 464.37 676.48 2.71 679.60 128.83 682.72 335.11 685.84 466.58 676.54 3.42 679.66 132.63 682.78 337.98 685.90 468.78 676.60 4.21 679.72 136.47 682.84 340.69 685.96 470.97 676.66 5.08 679.78 140.33 682.90 343.19 686.02 473.16 676.72 6.03 679.84 144.23 682.96 345.42 686.08 475.33 676.78 7.06 679.90 148.17 683.02 347.66 686.14 477.49 676.84 8.16 679.96 152.12 683.08 350.61 686.20 479.64 676.90 9.34 680.02 156.11 683.14 353.53 686.26 481.79 676.96 10.60 680.08 160.13 683.20 356.44 686.32 483.92 677.02 11.93 680.14 164.16 683.26 359.31 686.38 486.04 677.08 13.34 680.20 168.22 683.32 362.17 686.44 488.16 677.14 14.82 680.26 172.31 683.38 365.00 686.50 490.26 677.20 16.38 680.32 176.41 683.44 367.81 686.56 492.36 677.26 18.00 680.38 180.54 683.50 370.60 686.62 494.45 677.32 19.70 680.44 184.68 683.56 373.37 686.68 496.53 677.38 21.47 680.50 188.84 683.62 376.12 686.74 498.60 677.44 23.31 680.56 193.01 683.68 378.85 686.80 500.66 677.50 25.21 680.62 197.20 683.74 381.56 686.86 502.71 677.56 27.19 680.68 201.39 683.80 384.25 686.92 504.76 677.62 29.23 680.74 205.60 683.86 386.92 686.98 506.79 677.68 31.34 680.80 209.82 683.92 389.58 687.04 508.82 677.74 33.52 680.86 214.04 683.98 392.21 687.10 510.84 677.80 35.76 680.92 218.27 684.04 394.83 687.16 512.85 677.86 38.06 680.98 222.50 684.10 397.43 687.22 514.86 677.92 40.43 681.04 226.73 684.16 400.01 687.28 516.86 677.98 42.86 681.10 230.97 684.22 402.58 687.34 518.85 678.04 45.36 681.16 235.20 684.28 405.13 687.40 520.83 678.10 47.91 681.22 239.42 684.34 407.66 687.46 522.80 678.16 50.52 681.28 243.64 684.40 410.18 687.52 524.77 678.22 53.20 681.34 247.85 684.46 412.69 687.58 526.73 678.28 55.93 681.40 252.04 684.52 415.18 687.64 528.68 678.34 58.71 681.46 256.23 684.58 417.65 687.70 530.62 678.40 61.56 681.52 260.39 684.64 420.11 687.76 532.56 678.46 64.46 681.58 264.54 684.70 422.55 687.82 534.49 678.52 67.41 681.64 268.67 684.76 424.98 687.88 536.42 678.58 70.42 681.70 272.78 684.82 427.40 687.94 538.33 678.64 73.48 681.76 276.85 684.88 429.80 688.00 540.24 678.70 76.60 681.82 280.90 684.94 432.19 678.76 79.76 681.88 284.91 685.00 434.57 678.82 82.97 681.94 288.89 685.06 436.94 678.88 86.24 682.00 292.83 685.12 439.29 678.94 89.55 682.06 296.72 685.18 441.63 679.00 92.90 682.12 300.56 685.24 443.95 679.06 96.31 682.18 304.36 685.30 446.27 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 27 Stage -Area -Storage for Pond Pond B1: Pond B1 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 676.00 75,404 0 683.80 272,938 1,325,260 676.15 78,811 11,566 683.95 277,148 1,366,517 676.30 82,218 23,643 684.10 281,542 1,408,414 676.45 85,625 36,232 684.25 286,028 1,450,981 676.60 89,032 49,331 684.40 290,513 1,494,222 676.75 92,440 62,941 684.55 294,999 1,538,135 676.90 95,847 77,063 684.70 299,485 1,582,722 677.05 99,254 91,695 684.85 303,971 1,627,981 677.20 102,661 106,839 685.00 308,457 1,673,913 677.35 106,068 122,494 685.15 312,943 1,720,518 677.50 109,475 138,659 685.30 317,429 1,767,796 677.65 112,882 155,336 685.45 321,915 1,815,747 677.80 116,289 172,524 685.60 326,401 1,864,370 677.95 119,696 190,223 685.75 330,887 1,913,667 678.10 123,289 208,442 685.90 335,372 1,963,636 678.25 126,975 227,212 686.05 339,950 2,014,281 678.40 130,660 246,534 686.20 344,712 2,065,631 678.55 134,346 266,410 686.35 349,474 2,117,695 678.70 138,032 286,838 686.50 354,237 2,170,473 678.85 141,717 307,819 686.65 358,999 2,223,966 679.00 145,403 329,354 686.80 363,761 2,278,172 679.15 149,089 351,440 686.95 368,523 2,333,094 679.30 152,774 374,080 687.10 373,285 2,388,729 679.45 156,460 397,273 687.25 378,047 2,445,079 679.60 160,146 421,018 687.40 382,809 2,502,143 679.75 163,831 445,316 687.55 387,571 2,559,922 679.90 167,517 470,167 687.70 392,333 2,618,415 680.05 171,285 495,573 687.85 397,095 2,677,622 680.20 175,219 521,561 688.00 401,857 2,737,543 680.35 179,152 548,139 680.50 183,086 575,307 680.65 187,019 603,065 680.80 190,953 631,413 680.95 194,886 660,351 681.10 198,820 689,879 681.25 202,753 719,997 681.40 206,687 750,705 681.55 210,620 782,003 681.70 214,554 813,891 681.85 218,487 846,369 682.00 222,421 879,437 682.15 226,631 913,116 682.30 230,840 947,426 682.45 235,050 982,368 682.60 239,260 1,017,941 682.75 243,470 1,054,146 682.90 247,679 1,090,982 683.05 251,889 1,128,450 683.20 256,099 1,166,549 683.35 260,309 1,205,280 683.50 264,519 1,244,642 683.65 268,728 1,284,635 ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 28 Summary for Pond Pond B2: Pond B2 [79] Warning: Submerged Pond Pond B1 Primary device # 1 OUTLET by 3.97' Inflow Area = Inflow = Outflow = Primary = 278.800 ac, 0.00% Impervious, Inflow Depth > 6.82" for NRCC-100yr-24hr event 489.01 cfs @ 12.90 hrs, Volume= 158.426 af 365.70 cfs @ 14.07 hrs, Volume= 145.363 af, Atten= 25%, Lag= 70.1 min 365.70 cfs @ 14.07 hrs, Volume= 145.363 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 614.00' Surf.Area= 213,648 sf Storage= 1,110,739 cf Peak Elev= 620.97' @ 14.07 hrs Surf.Area= 261,730 sf Storage= 2,782,860 cf (1,672,121 cf above start) Plug -Flow detention time= 234.2 min calculated for 119.739 af (76% of inflow) Center -of -Mass det. time= 98.8 min (948.2 - 849.4 ) Volume Invert Avail.Storage Storage Description #1 Elevation (feet) 608.00 610.00 612.00 616.00 618.00 620.00 622.00 608.00' 3,055,722 cf Custom Stage Data (Prismatic)Listed below (Recalc) Device Routing Surf.Area (sq-ft) 148,967 178,807 195,255 232,041 243,810 255,804 268,025 Invert Inc.Store (cubic -feet) 0 327,774 374,062 854,592 475,851 499,614 523,829 Outlet Devices Cum.Store (cubic -feet) 0 327,774 701,836 1,556,428 2,032,279 2,531,893 3,055,722 #1 Primary #2 Device 1 #3 Device 1 608.00' 614.00' 617.00' 66.0" Round Culvert L= 280.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 608.00' / 604.00' S= 0.0143'/' Cc= 0.900 n= 0.013, Flow Area= 23.76 sf 7.0" Vert. Orifice/Grate C= 0.600 40.0' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=365.69 cfs @ 14.07 hrs HW=620.97' (Free Discharge) 4-1=Culvert (Inlet Controls 365.69 cfs @ 15.39 fps) AL2=Orifice/Grate (Passes < 3.33 cfs potential flow) 3=Sharp-Crested Rectangular Weir(Passes < 1,034.36 cfs potential flow) ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 0 LL 500:" 450� 400: 350- 300J 250- 200- 150 100- 50 Pond Pond B2: Pond B2 Hyd rog raph NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 29 489.01 cfs 4 8 365.70 I, 04 10 12 14 16 it r i t inflow Aroma=278.8QQac-- p ea ▪ Stbrrge=2,±8Zr8&0_cf- 4 4 4 18 L 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Pond Pond B2: Pond B2 Stage -Discharge 622/ 6211- 620- 6191- 618- 617 w 616 0 615 w • 614 w 613 612 611 610 609 608 Sharp -Crested Rectangular Weir 0 Orifice/rate 4 4 4 L 4 ✓ 50 100 1 150 200 Discharge (cfs) 250 L 4 r 300 350 D Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 30 Elevation (feet) Pond Pond B2: Pond B2 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000180,000 200,000 220,000240,000 260,000 622_ I I I I I I LIr r II 621_ -----Ir + + + r T r rr 620� I I 619- 618- 617- 616- 615- 614- zz 613- 612= 611 610- 609= Custom Stage Data 608 0 IL 500,000 ri -II I I I r r-r--r----r--r-r----r---rr 1,000,000 71 r T r r 4- r 1,500,000 2,000,000 Storage (cubic -feet) 2,500,000 3,000,000 Surface ❑ Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 ©2019 HydroCAD Software Solutions LLC Page 31 Stage -Discharge for Pond Pond B2: Pond B2 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 608.00 0.00 615.80 1.58 608.15 0.00 615.95 1.66 608.30 0.00 616.10 1.73 608.45 0.00 616.25 1.80 608.60 0.00 616.40 1.87 608.75 0.00 616.55 1.93 608.90 0.00 616.70 2.00 609.05 0.00 616.85 2.06 609.20 0.00 617.00 2.12 609.35 0.00 617.15 9.77 609.50 0.00 617.30 23.72 609.65 0.00 617.45 41.77 609.80 0.00 617.60 63.13 609.95 0.00 617.75 87.35 610.10 0.00 617.90 114.12 610.25 0.00 618.05 143.23 610.40 0.00 618.20 174.49 610.55 0.00 618.35 207.76 610.70 0.00 618.50 242.93 610.85 0.00 618.65 279.91 611.00 0.00 618.80 318.61 611.15 0.00 618.95 327.58 611.30 0.00 619.10 330.56 611.45 0.00 619.25 333.52 611.60 0.00 619.40 336.45 611.75 0.00 619.55 339.35 611.90 0.00 619.70 342.23 612.05 0.00 619.85 345.09 612.20 0.00 620.00 347.92 612.35 0.00 620.15 350.73 612.50 0.00 620.30 353.52 612.65 0.00 620.45 356.28 612.80 0.00 620.60 359.03 612.95 0.00 620.75 361.75 613.10 0.00 620.90 364.45 613.25 0.00 621.05 367.14 613.40 0.00 621.20 369.80 613.55 0.00 621.35 372.45 613.70 0.00 621.50 375.07 613.85 0.00 621.65 377.68 614.00 0.00 621.80 380.27 614.15 0.07 621.95 382.84 614.30 0.26 614.45 0.51 614.60 0.71 614.75 0.87 614.90 1.00 615.05 1.12 615.20 1.23 615.35 1.32 615.50 1.41 615.65 1.50 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 32 Stage -Area -Storage for Pond Pond B2: Pond B2 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 608.00 148,967 0 615.80 230,202 1,510,204 608.15 151,205 22,513 615.95 231,581 1,544,837 608.30 153,443 45,361 616.10 232,629 1,579,662 608.45 155,681 68,546 616.25 233,512 1,614,622 608.60 157,919 92,066 616.40 234,395 1,649,715 608.75 160,157 115,922 616.55 235,277 1,684,941 608.90 162,395 140,113 616.70 236,160 1,720,298 609.05 164,633 164,640 616.85 237,043 1,755,789 609.20 166,871 189,503 617.00 237,926 1,791,411 609.35 169,109 214,701 617.15 238,808 1,827,166 609.50 171,347 240,236 617.30 239,691 1,863,054 609.65 173,585 266,105 617.45 240,574 1,899,074 609.80 175,823 292,311 617.60 241,456 1,935,226 609.95 178,061 318,852 617.75 242,339 1,971,510 610.10 179,629 345,696 617.90 243,222 2,007,927 610.25 180,863 372,733 618.05 244,110 2,044,477 610.40 182,097 399,955 618.20 245,009 2,081,161 610.55 183,330 427,362 618.35 245,909 2,117,980 610.70 184,564 454,954 618.50 246,809 2,154,934 610.85 185,797 482,731 618.65 247,708 2,192,022 611.00 187,031 510,693 618.80 248,608 2,229,246 611.15 188,265 538,840 618.95 249,507 2,266,605 611.30 189,498 567,172 619.10 250,407 2,304,098 611.45 190,732 595,690 619.25 251,306 2,341,727 611.60 191,965 624,392 619.40 252,206 2,379,490 611.75 193,199 653,279 619.55 253,105 2,417,388 611.90 194,433 682,352 619.70 254,005 2,455,422 612.05 195,715 711,610 619.85 254,904 2,493,590 612.20 197,094 741,071 620.00 255,804 2,531,893 612.35 198,474 770,739 620.15 256,721 2,570,332 612.50 199,853 800,613 620.30 257,637 2,608,909 612.65 201,233 830,695 620.45 258,554 2,647,623 612.80 202,612 860,983 620.60 259,470 2,686,475 612.95 203,992 891,478 620.75 260,387 2,725,465 613.10 205,371 922,180 620.90 261,303 2,764,591 613.25 206,751 953,090 621.05 262,220 2,803,856 613.40 208,130 984,206 621.20 263,137 2,843,257 613.55 209,510 1,015,529 621.35 264,053 2,882,797 613.70 210,889 1,047,058 621.50 264,970 2,922,473 613.85 212,269 1,078,795 621.65 265,886 2,962,288 614.00 213,648 1,110,739 621.80 266,803 3,002,239 614.15 215,027 1,142,890 621.95 267,719 3,042,328 614.30 216,407 1,175,247 614.45 217,786 1,207,812 614.60 219,166 1,240,583 614.75 220,545 1,273,562 614.90 221,925 1,306,747 615.05 223,304 1,340,139 615.20 224,684 1,373,738 615.35 226,063 1,407,544 615.50 227,443 1,441,557 615.65 228,822 1,475,777 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 33 Summary for Pond Pond C1: Pond C1 Inflow Area = 533.800 ac, 0.00% Impervious, Inflow Depth = 6.35" for NRCC-100yr-24hr event Inflow = 2,356.30 cfs @ 12.41 hrs, Volume= 282.572 af Outflow = 518.18 cfs @ 13.20 hrs, Volume= 280.511 af, Atten= 78%, Lag= 47.3 min Primary = 518.18 cfs @ 13.20 hrs, Volume= 280.511 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 681.15' @ 13.20 hrs Surf.Area= 404,267 sf Storage= 5,401,245 cf Plug -Flow detention time= 132.2 min calculated for 280.219 af (99% of inflow) Center -of -Mass det. time= 128.4 min (926.0 - 797.6 ) Volume Invert Avail.Storage Storage Description #1 664.00' 6,161,365 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 664.00 49,861 0 0 665.00 106,320 78,091 78,091 668.00 311,540 626,790 704,881 670.00 324,958 636,498 1,341,379 675.00 359,560 1,711,295 3,052,674 680.00 395,673 1,888,083 4,940,756 683.00 418,066 1,220,609 6,161,365 Device Routing Invert Outlet Devices #1 Primary 665.00' 72.0" Round Culvert L= 991.0' RCP, groove end w/headwall, Ke= 0.200 Inlet / Outlet Invert= 665.00' / 654.00' S= 0.0111 '/' Cc= 0.900 n= 0.013, Flow Area= 28.27 sf Primary OutFlow Max=518.17 cfs @ 13.20 hrs HW=681.15' (Free Discharge) 4-1=Culvert (Barrel Controls 518.17 cfs @ 18.33 fps) ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 2,6007: 2,400- 2,200 2,000J 1,8007- 1, 600� 0 1,400L-- 1,200- LL 1,000- 8007: 600� 400- 200- Elevation (feet) 2 4 1 L 4 L r 7 7 7 7 1__L 4 — — L L 12,356.30 cfs r 1 1 518.18 c Hyd rog raph 1 Pond Pond C1: Pond C1 1 1 1 1 7 1 1 1 1 1 L NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 34 1 L 1 1 L + + 1 + i 11-1 1 Inflow -A $a 533.8Q0'; ac- Pea11r 1ev=68t1$1 Storage=5,401,245 cf L 1 1 L 72.0" 1 L 1 gurjd Culvert Y r n=0M13 7 L=991.0-' sg,o1-t1-t/'- 1 L 1 L 1-1 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Pond Pond C1: Pond C1 Stage -Discharge 683 _ 682� 681=/ - 680- 679- + 678� 677=- 676— L 675— )_ 674- ,L 673� 672- 671"=" 670- 1 669 668��_ 667� 666: ---- Culver; 7 7 + 1 1 1 1 7 7 1 + �r 1 1 1 665 664 1 1 1 T T T -r L 1 1 1 L 1 0 50 100 150 200 250 300 Discharge (cfs) 350 400 450 500 C Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Elevation (feet) 683 682� 681- z 680 679 678J 677 676 675 674J 673 672J 671= 670 669 668 667' 666 665 664 0 Pond Pond C1: Pond C1 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 35 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 I I I ' I I I 1 I 1,000,000 2,000,000 1 ri 1i 3,000,000 4,000,000 Storage (cubic -feet) L 5,000,000 6,000,000 Surface ❑ Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 36 Stage -Discharge for Pond Pond Cl: Pond C1 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 664.00 0.00 674.40 427.55 664.20 0.00 674.60 430.51 664.40 0.00 674.80 433.45 664.60 0.00 675.00 436.37 664.80 0.00 675.20 439.27 665.00 0.00 675.40 442.15 665.20 0.48 675.60 445.01 665.40 2.12 675.80 447.86 665.60 4.85 676.00 450.68 665.80 8.53 676.20 453.49 666.00 13.18 676.40 456.28 666.20 18.77 676.60 459.05 666.40 25.25 676.80 461.81 666.60 32.58 677.00 464.55 666.80 40.73 677.20 467.28 667.00 49.66 677.40 469.98 667.20 59.30 677.60 472.68 667.40 69.63 677.80 475.36 667.60 80.59 678.00 478.02 667.80 92.14 678.20 480.67 668.00 104.21 678.40 483.30 668.20 116.76 678.60 485.92 668.40 129.72 678.80 488.53 668.60 143.03 679.00 491.12 668.80 156.63 679.20 493.70 669.00 170.44 679.40 496.26 669.20 184.38 679.60 498.81 669.40 198.38 679.80 501.35 669.60 212.32 680.00 503.88 669.80 226.10 680.20 506.39 670.00 239.59 680.40 508.89 670.20 252.65 680.60 511.38 670.40 265.07 680.80 513.86 670.60 276.61 681.00 516.32 670.80 286.83 681.20 518.77 671.00 294.75 681.40 521.21 671.20 304.42 681.60 523.64 671.40 313.79 681.80 526.06 671.60 322.88 682.00 528.47 671.80 331.73 682.20 530.87 672.00 340.35 682.40 533.25 672.20 348.76 682.60 535.63 672.40 356.96 682.80 537.99 672.60 364.99 683.00 540.35 672.80 372.84 673.00 380.52 673.20 388.06 673.40 395.45 673.60 402.71 673.80 409.84 674.00 416.84 674.20 423.73 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 37 Stage -Area -Storage for Pond Pond Cl: Pond C1 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 664.00 49,861 0 674.40 355,408 2,838,183 664.20 61,153 11,101 674.60 356,792 2,909,403 664.40 72,445 24,461 674.80 358,176 2,980,900 664.60 83,736 40,079 675.00 359,560 3,052,674 664.80 95,028 57,956 675.20 361,005 3,124,730 665.00 106,320 78,091 675.40 362,449 3,197,075 665.20 120,001 100,723 675.60 363,894 3,269,710 665.40 133,683 126,091 675.80 365,338 3,342,633 665.60 147,364 154,196 676.00 366,783 3,415,845 665.80 161,045 185,037 676.20 368,227 3,489,346 666.00 174,727 218,614 676.40 369,672 3,563,136 666.20 188,408 254,927 676.60 371,116 3,637,214 666.40 202,089 293,977 676.80 372,561 3,711,582 666.60 215,771 335,763 677.00 374,005 3,786,239 666.80 229,452 380,285 677.20 375,450 3,861,184 667.00 243,133 427,544 677.40 376,894 3,936,419 667.20 256,815 477,539 677.60 378,339 4,011,942 667.40 270,496 530,270 677.80 379,783 4,087,754 667.60 284,177 585,737 678.00 381,228 4,163,855 667.80 297,859 643,941 678.20 382,672 4,240,245 668.00 311,540 704,881 678.40 384,117 4,316,924 668.20 312,882 767,323 678.60 385,561 4,393,892 668.40 314,224 830,033 678.80 387,006 4,471,149 668.60 315,565 893,012 679.00 388,450 4,548,694 668.80 316,907 956,259 679.20 389,895 4,626,529 669.00 318,249 1,019,775 679.40 391,339 4,704,652 669.20 319,591 1,083,559 679.60 392,784 4,783,065 669.40 320,933 1,147,611 679.80 394,228 4,861,766 669.60 322,274 1,211,932 680.00 395,673 4,940,756 669.80 323,616 1,276,521 680.20 397,166 5,020,040 670.00 324,958 1,341,379 680.40 398,659 5,099,622 670.20 326,342 1,406,509 680.60 400,152 5,179,503 670.40 327,726 1,471,915 680.80 401,644 5,259,683 670.60 329,110 1,537,599 681.00 403,137 5,340,161 670.80 330,494 1,603,559 681.20 404,630 5,420,938 671.00 331,878 1,669,797 681.40 406,123 5,502,013 671.20 333,262 1,736,311 681.60 407,616 5,583,387 671.40 334,647 1,803,102 681.80 409,109 5,665,060 671.60 336,031 1,870,169 682.00 410,602 5,747,031 671.80 337,415 1,937,514 682.20 412,095 5,829,300 672.00 338,799 2,005,135 682.40 413,587 5,911,868 672.20 340,183 2,073,033 682.60 415,080 5,994,735 672.40 341,567 2,141,208 682.80 416,573 6,077,901 672.60 342,951 2,209,660 683.00 418,066 6,161,365 672.80 344,335 2,278,389 673.00 345,719 2,347,394 673.20 347,103 2,416,677 673.40 348,487 2,486,236 673.60 349,871 2,556,071 673.80 351,256 2,626,184 674.00 352,640 2,696,574 674.20 354,024 2,767,240 ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 38 [79] Warning: Inflow Area = Inflow = Outflow = Primary = Summary for Pond Pond C2: Pond C2 Submerged Pond Pond C1 Primary device # 1 OUTLET by 2.72' 533.800 ac, 0.00% Impervious, Inflow Depth > 6.31" for NRCC-100yr-24hr event 518.18 cfs @ 13.20 hrs, Volume= 280.511 af 424.39 cfs @ 15.79 hrs, Volume= 257.423 af, Atten= 18%, Lag= 155.7 min 424.39 cfs @ 15.79 hrs, Volume= 257.423 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 650.00' Surf.Area= 386,547 sf Storage= 1,749,912 cf Peak Elev= 656.72' @ 15.79 hrs Surf.Area= 442,406 sf Storage= 4,545,124 cf (2,795,212 cf above start) Plug -Flow detention time= 250.8 min calculated for 217.251 af (77% of inflow) Center -of -Mass det. time= 112.4 min (1,038.4 - 926.0 ) Volume Invert Avail.Storage Storage Description #1 Elevation (feet) 644.00 646.00 648.00 650.00 652.00 654.00 656.00 657.50 644.00' 4,893,576 cf Custom Stage Data (Prismatic)Listed below (Recalc) Surf.Area (sq-ft) 223,281 260,873 309,169 386,547 406,548 421,590 436,857 448,455 Device Routing Invert Inc.Store (cubic -feet) 0 484,154 570,042 695,716 793,095 828,138 858,447 663,984 Outlet Devices Cum.Store (cubic -feet) 0 484,154 1,054,196 1,749,912 2,543,007 3,371,145 4,229,592 4,893,576 #1 Primary 644.00' #2 Device 1 #3 Device 1 650.00' 653.00' 72.0" Round Culvert L= 424.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 644.00' / 626.00' S= 0.0425'/' Cc= 0.900 n= 0.013, Flow Area= 28.27 sf 10.0" Vert. Orifice/Grate C= 0.600 40.0' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=424.39 cfs @ 15.79 hrs HW=656.72' (Free Discharge) 4-1=Culvert (Inlet Controls 424.39 cfs @ 15.01 fps) AL2=Orifice/Grate (Passes < 6.59 cfs potential flow) 3=Sharp-Crested Rectangular Weir(Passes < 937.58 cfs potential flow) ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 550— 500J 450— 400J 350� • 300 0 u 250- 200� 150= 100- 50=- 657J 656— 655-' 6541- 653 w ▪ 652 0 c 651 w 650 w 649 648 647 646 645 644 Pond Pond C2: Pond C2 Hyd rog raph 518.18 cfs NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Printed 11/15/2021 Page 39 Inflow Area 533.800 ac Pea1C elev=656;72' Storage=4,545,124 cf 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Pond Pond C2: Pond C2 Stage -Discharge T T Sharp -Crested Rectangular Weir T T 1 1 T T 1 T 1 1 H T 0 50 100 150 200 250 Discharge (cfs) 300 400 D Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 40 Elevation (feet) 657J 656J 655+:- 6547:' 6537- 652J 651�� 650= 649J 648- 647- 646: 645: 644 50,000 Pond Pond C2: Pond C2 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 100,000 150,000 200,000 250,000 300,000 Custom Stage Data i i 350,000 400,000 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000 3,500,000 4,000,000 4,500,000 Storage (cubic -feet) ■ Surface` • Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 41 Stage -Discharge for Pond Pond C2: Pond C2 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 644.00 0.00 651.80 3.09 644.15 0.00 651.95 3.25 644.30 0.00 652.10 3.41 644.45 0.00 652.25 3.56 644.60 0.00 652.40 3.70 644.75 0.00 652.55 3.84 644.90 0.00 652.70 3.97 645.05 0.00 652.85 4.10 645.20 0.00 653.00 4.22 645.35 0.00 653.15 11.94 645.50 0.00 653.30 25.95 645.65 0.00 653.45 44.06 645.80 0.00 653.60 65.48 645.95 0.00 653.75 89.75 646.10 0.00 653.90 116.58 646.25 0.00 654.05 145.74 646.40 0.00 654.20 177.05 646.55 0.00 654.35 210.38 646.70 0.00 654.50 245.60 646.85 0.00 654.65 282.63 647.00 0.00 654.80 321.37 647.15 0.00 654.95 361.76 647.30 0.00 655.10 387.46 647.45 0.00 655.25 391.03 647.60 0.00 655.40 394.57 647.75 0.00 655.55 398.08 647.90 0.00 655.70 401.56 648.05 0.00 655.85 405.00 648.20 0.00 656.00 408.42 648.35 0.00 656.15 411.81 648.50 0.00 656.30 415.17 648.65 0.00 656.45 418.51 648.80 0.00 656.60 421.82 648.95 0.00 656.75 425.10 649.10 0.00 656.90 428.36 649.25 0.00 657.05 431.59 649.40 0.00 657.20 434.80 649.55 0.00 657.35 437.98 649.70 0.00 657.50 441.14 649.85 0.00 650.00 0.00 650.15 0.09 650.30 0.33 650.45 0.69 650.60 1.11 650.75 1.52 650.90 1.83 651.05 2.09 651.20 2.32 651.35 2.54 651.50 2.73 651.65 2.92 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 42 Stage -Area -Storage for Pond Pond C2: Pond C2 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 644.00 223,281 0 651.80 404,548 2,461,897 644.15 226,100 33,704 651.95 406,048 2,522,692 644.30 228,920 67,830 652.10 407,300 2,583,699 644.45 231,739 102,380 652.25 408,428 2,644,879 644.60 234,559 137,352 652.40 409,556 2,706,228 644.75 237,378 172,747 652.55 410,685 2,767,746 644.90 240,197 208,565 652.70 411,813 2,829,433 645.05 243,017 244,806 652.85 412,941 2,891,290 645.20 245,836 281,470 653.00 414,069 2,953,316 645.35 248,656 318,557 653.15 415,197 3,015,510 645.50 251,475 356,067 653.30 416,325 3,077,875 645.65 254,294 394,000 653.45 417,453 3,140,408 645.80 257,114 432,355 653.60 418,582 3,203,111 645.95 259,933 471,134 653.75 419,710 3,265,983 646.10 263,288 510,362 653.90 420,838 3,329,024 646.25 266,910 550,127 654.05 421,972 3,392,234 646.40 270,532 590,435 654.20 423,117 3,455,616 646.55 274,154 631,287 654.35 424,262 3,519,169 646.70 277,777 672,681 654.50 425,407 3,582,894 646.85 281,399 714,620 654.65 426,552 3,646,791 647.00 285,021 757,101 654.80 427,697 3,710,860 647.15 288,643 800,126 654.95 428,842 3,775,100 647.30 292,265 843,694 655.10 429,987 3,839,512 647.45 295,888 887,805 655.25 431,132 3,904,096 647.60 299,510 932,460 655.40 432,277 3,968,852 647.75 303,132 977,658 655.55 433,422 4,033,779 647.90 306,754 1,023,400 655.70 434,567 4,098,878 648.05 311,103 1,069,703 655.85 435,712 4,164,149 648.20 316,907 1,116,804 656.00 436,857 4,229,592 648.35 322,710 1,164,775 656.15 438,017 4,295,208 648.50 328,514 1,213,617 656.30 439,177 4,360,997 648.65 334,317 1,263,329 656.45 440,336 4,426,961 648.80 340,120 1,313,912 656.60 441,496 4,493,098 648.95 345,924 1,365,365 656.75 442,656 4,559,409 649.10 351,727 1,417,689 656.90 443,816 4,625,895 649.25 357,530 1,470,883 657.05 444,976 4,692,554 649.40 363,334 1,524,948 657.20 446,135 4,759,387 649.55 369,137 1,579,883 657.35 447,295 4,826,395 649.70 374,940 1,635,689 657.50 448,455 4,893,576 649.85 380,744 1,692,365 650.00 386,547 1,749,912 650.15 388,047 1,808,007 650.30 389,547 1,866,326 650.45 391,047 1,924,871 650.60 392,547 1,983,640 650.75 394,047 2,042,635 650.90 395,547 2,101,855 651.05 397,048 2,161,299 651.20 398,548 2,220,969 651.35 400,048 2,280,863 651.50 401,548 2,340,983 651.65 403,048 2,401,328 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 43 Summary for Link A-1: Outfall Al Inflow Area = 278.500 ac, 0.00% Impervious, Inflow Depth > 5.93" for NRCC-100yr-24hr event Inflow = 530.21 cfs @ 12.47 hrs, Volume= 137.525 af Primary = 530.21 cfs @ 12.47 hrs, Volume= 137.525 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 550-' 500J 450- 400- 350:- 300- 250: 200- 150- 100- Link A-1: Outfall Al yd rog raph 530.21 cfs 530.21 cfs I p 0 2 4 6 8 10 12 14 16 18 20 4 22 24 26 Time (hours) nfIow Area= -70:500r ac- - 28 30 32 34 36 38 40 42 44 46 48 C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 44 Summary for Link A-2: Outfall A2 Inflow Area = 37.000 ac, 0.00% Impervious, Inflow Depth = 4.86" for NRCC-100yr-24hr event Inflow = 154.43 cfs @ 12.32 hrs, Volume= 14.977 af Primary = 154.43 cfs @ 12.32 hrs, Volume= 14.977 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 170, 160 150- 140� 130� 120�/ 110�/ w 100- o 90�, 0 80% LL 70 60 50- 40- 30= 20= 10= 0411 Link A-2: Outfall A2 Hyd rog raph 154.43 cfs I 1154.43 cfs J T ▪ 1 J J r IT r Inflow J--I-_+-- J 1 1 i J 1 J 1 Are0_ $7.000! ac J + + J Lk 1 T IT 1 + 1 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 45 Summary for Link B-1: Total DA B Inflow Area = 312.300 ac, 0.00% Impervious, Inflow Depth > 6.05" for NRCC-100yr-24hr event Inflow = 415.71 cfs @ 12.56 hrs, Volume= 157.366 af Primary = 415.71 cfs @ 12.56 hrs, Volume= 157.366 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 460 440J 420J 4007:- 3804 360' 3407:- 3204" 300 28O ' ▪ 260 240 0 220< LL 200- 180 160 140= 120' 100 80=' 60= 40 20=' 0 1 1 1 1 L i i r r Link B-1: Total DA B Hyd rog raph 1 L 1 L I 1 1 L 1 1 L 4 r r T1-1 I nfl ova A e _ al 100; ac 1 L I J 1 L 1 1 L 1 l 7 r r 7 r r T r r r 1 L I J 1 L 1 1 L 1 l 7 r 1 7 7 r 7 T r 7 T 4 L - 4 I+ -4 + I+ 4 L 1 L 1 J 1 L I 1 1 L I 1 L rt Y 1 7 Y r 7 t r 1 7 Y + + 1 + + + + + + + + 1 L 1 J 1 L 1 1 L 1 L ✓ i i r i i 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 46 Summary for Link B-2: Outfall B2 Inflow Area = 62.000 ac, 0.00% Impervious, Inflow Depth = 3.86" for NRCC-100yr-24hr event Inflow = 176.58 cfs @ 12.43 hrs, Volume= 19.950 af Primary = 176.58 cfs @ 12.43 hrs, Volume= 19.950 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 190 " 180H 170H- 160 150H 140 130 120H- u 110� 3 100 , 0 90_ LL 80 70 " 60= 50= 40� 30 20- 1I 1 I + 4- 176.58 cfs + 1176.58 cfs r } r T 10 jz %_ nYr-rrYT+-r^ 0 2 4 6 8 10 12 14 16 Link B-2: Outfall B2 Hyd rog raph L T L 4 4 4 T T T L L L L r 1 1 r Are 6-2.o or aa- - T T T r T T T 1- 4 T —I + r r 1L L r r r T L r 18 20 22 24 26 Time (hours) 28 30 32 34 36 38 40 42 44 46 48 C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-100yr-24hr Rainfall=7.42" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 47 Summary for Link C: Total DA C Inflow Area = 879.200 ac, 0.00% Impervious, Inflow Depth > 5.23" for NRCC-100yr-24hr event Inflow = 1,143.62 cfs @ 12.73 hrs, Volume= 383.074 af Primary = 1,143.62 cfs @ 12.73 hrs, Volume= 383.074 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 4 1,200:- -+ 1,1007- H 1,0007- -r 900- 800L' w 700— 6001 LL 500L" 400- L i 3001' / 200- 100- 4 7 Link C: Total DA C Hyd rog raph Inflow Arpa=879.2O0 ac r 7- L 7 4- r r 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 48 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentAl: Al -A SubcatchmentA2: A2 SubcatchmentA3.U: DAA1 SubcatchmentA4.U: DA A2 SubcatchmentBl: B1-A SubcatchmentB2.U: DA B2.0 SubcatchmentB3.U: DA B3.0 SubcatchmentCl: C1-A SubcatchmentC2.U: DA C2.0 SubcatchmentC3.U: DA C3.0 Pond Pond A3: Pond A3 Runoff Area=99.300 ac 0.00% Impervious Runoff Depth=4.35" Tc=20.0 min CN=94 Runoff=364.42 cfs 35.975 af Runoff Area=125.300 ac 0.00% Impervious Runoff Depth=4.46" Tc=25.0 min CN=95 Runoff=420.37 cfs 46.561 af RunoffArea=53.900 ac 0.00% Impervious Runoff Depth=2.57" Tc=30.0 min CN=76 Runoff=102.04 cfs 11.537 af RunoffArea=37.000 ac 0.00% Impervious Runoff Depth=2.75" Tc=22.0 min CN=78 Runoff=87.90 cfs 8.466 af RunoffArea=278.800 ac 0.00% Impervious Runoff Depth=4.46" Tc=30.0 min CN=95 Runoff=851.32 cfs 103.601 af RunoffArea=33.500 ac 0.00% Impervious Runoff Depth=2.31" Tc=30.0 min CN=73 Runoff=56.73 cfs 6.454 af RunoffArea=62.000 ac 0.00% Impervious Runoff Depth=1.99" Tc=30.0 min CN=69 Runoff=88.85 cfs 10.263 af RunoffArea=533.800 ac 0.00% Impervious Runoff Depth=4.02" Tc=30.0 min CN=91 Runoff=1,527.46 cfs 178.864 af Runoff Area=183.000 ac 0.00% Impervious Runoff Depth=2.48" Tc=50.0 min CN=75 Runoff=249.95 cfs 37.847 af RunoffArea=162.400 ac 0.00% Impervious Runoff Depth=2.23" Tc=45.0 min CN=72 Runoff=211.17 cfs 30.162 of Peak Elev=687.28' Storage=2,612,029 cf Inflow=775.28 cfs 82.536 af Outflow=194.81 cfs 72.563 af Pond Pond B1: Pond B1 Peak Elev=683.88' Storage=1,346,008 cf Inflow=851.32 cfs 103.601 af 84.0" Round Culvert n=0.013 L=711.0' S=0.0830 '/' Outflow=387.61 cfs 103.491 af Pond Pond B2: Pond B2 Peak EIev=619.10' Storage=2,304,541 cf Inflow=387.61 cfs 103.491 af Outflow=330.59 cfs 90.491 af Pond Pond C1: Pond C1 Peak EIev=675.47' Storage=3,224,204 cf Inflow=1,527.46 cfs 178.864 af 72.0" Round Culvert n=0.013 L=991.0' S=0.0111 '/' Outflow=443.22 cfs 176.812 af Pond Pond C2: Pond C2 Peak EIev=655.10' Storage=3,841,601 cf Inflow=443.22 cfs 176.812 af Outflow=387.58 cfs 153.916 af LinkA-1: OutfallA1 Inflow=278.19 cfs 84.099 af Primary=278.19 cfs 84.099 af ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 49 Link A-2: Outfall A2 Link B-1: Total DA B Link B-2: Outfall B2 Link C: Total DA C Inflow=87.90 cfs 8.466 af Primary=87.90 cfs 8.466 af Inflow=347.70 cfs 96.945 af Primary=347.70 cfs 96.945 af Inflow=88.85 cfs 10.263 af Primary=88.85 cfs 10.263 af Inflow=511.88 cfs 221.924 af Primary=511.88 cfs 221.924 af Total Runoff Area = 1,569.000 ac Runoff Volume = 469.730 af Average Runoff Depth = 3.59" 100.00% Pervious = 1,569.000 ac 0.00% Impervious = 0.000 ac ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 50 Summary for Subcatchment Al: Al -A Runoff = 364.42 cfs @ 12.29 hrs, Volume= 35.975 af, Depth= 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 99.300 94 99.300 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 20.0 Direct Entry, Subcatchment Al: Al -A Hydrograph 380=- 360 ,+ 340,- , ,+ 320� + 300/ 280- fi 240� ., 220,- 200 LT_ 180+:- I 160 140,, 120-7:- - - 1 00i/ k 80= 60� fi 40= 20= 1 L 7 T 364.42 cfs 1 • 1 1 L I I NRscc +--+--+--+ + + + ▪ rt • T • 1 ▪ L t r T T T J 41 I 1 1 L 4 t C_24ihr iB _ - 0yr-24hr Ra'hi faJr= K,i - unof Area=99.300 ac Runoff Verutne=35975- f - ▪ Ruroff-Deptfl=4:34" - 1 + L ▪ L L T r r Tc 20 QI m'in - CN=94- 1 1 1 1 + — — + T 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 51 Summary for Subcatchment A2: A2 Runoff = 420.37 cfs @ 12.35 hrs, Volume= 46.561 af, Depth= 4.46" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 125.300 95 125.300 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 25.0 Direct Entry, Subcatchment A2: A2 Hydrograph 460_ 1 4407:" + + -+ 1 420� 400- 1 1 380- )- i i 1 rt L 360 340� z ) ' ' - - 4- 320� )- -1 rt + 300 280 /L -1 1 -L 4- 13 26017-iJ / ri L 240� z 1 0 220� k 1 1 2007:" - - - L 180� / ' 160� k 1 1 L 140=zT 7 7 T 120' ' L r 1 1 L L i i i 1 L L 1 L NRCC 24»hrB 1 L L aRN✓ -'I Oyr-2411r Rairtf $.Q4„ -1 rt + r ▪ 1 + + Runoff-Araa=fi2 d0 ac - Runoff V6Futne46:561-af - 1 ur_of -Dept1 =4.40„ + ▪ -F T + i i i + 1 4 L L i i i 1 L r 1 1 T L i i i 7 L r 100- +-------+--+--+ 80� + 7 7 T 7 7 T t 7 L r 7 T 200_, 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 52 Summary for Subcatchment A3.U: DA Al Runoff = 102.04 cfs @ 12.43 hrs, Volume= 11.537 af, Depth= 2.57" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 53.900 76 53.900 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Subcatchment A3.U: DA Al Hydrograph L L L I I L L L L 110� r I r r + r 105- I I 1 102.04 cfs I 100±:" I I 95� 90� 1 85� 80t� I I -4 4 r 75z. r 70�I 1 w 65� , I L L L u 60 fi r r + 3 554:I LL 50 I I I 45J/+ I I --+--r 40� , r 1 r r 35� I I I 30 z,+ I I -4 4 r 25 r 20 I 15 10 5 0 8 10 12 r--r--+--r L I I I L L y--t--r rt--+ r NRNC 1�1R1C_24. hr B _ - r0',yr-24hr Rat fa11=5 .G4,• - I r + + + 1 1 1 T r I iunoft Area=53.S00-ac - RuhofrVf ru ne=1'1.537-4f - ▪ L L L I r--r--r--r r I I I 1 T Runoff-Dept-h=" - AI Ta=310. mile y--t--r C N-76 - 1 1 1 r 1 + + + + 1 T r I r 1 + + + • r 1 1 1 1 + L I I I L L 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 Time (hours) 44 46 48 • Runoff ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment A4.U: DA A2 Runoff = 87.90 cfs @ 12.32 hrs, Volume= 8.466 af, Depth= 2.75" NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 53 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 37.000 78 37.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 22.0 Direct Entry, Subcatchment A4.U: DA A2 Hydrograph 'i 95 90 85 80 75=-�' 70=',t 65='�fi 60=' 55=' fi 6 3 50 I 1- 0 45"/!r LL = 40=' II 35 + 30J I 25=' 20=' 15=-' , 10= T 5_440���������/����/ 4 4 4 4 I • 187.90 cfs I I + + Y Y Y Y ✓ ✓ ✓ ✓ ✓ r 4 4 4 4 4 4 I I I 4 4 4 4 + + 1I + + + + +I IURC-C-24-141t13- + 4 4 + + + I I I + + + + 1N RCC-a0_y_r--'1241tir- Rai ffa1L -&._0_4" + -Oujrof -Area -3- .O00 ac - T RUnd-ff Vohjn e=8.466-af t r I t--r T r r Run if DeWf4 —=-Z7V t t t t t r r r r Y r T T T T r r ✓ r r Y r I▪ r ✓ r r r r r T T T T r r ▪ -1 -11 T T 'r Ir Tc=22.0r m'hrr - ▪ YCN= S ▪ r r r r r II r Ir 4 4 4 Ir ✓ r T Ir Ir 8 10 12 14 16 18 20 22 24 26 28 30 Time (hours) 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 54 Summary for Subcatchment B1: B1-A Runoff = 851.32 cfs @ 12.41 hrs, Volume= 103.601 af, Depth= 4.46" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 278.800 95 278.800 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, 0 LL Subcatchment B1: B1-A Hydrograph 950-- 900� 850L 800 750 Too" 650- 600=- 550 500�j- 450=" 400= 350= 300'1' 250J 200' 150='/ 100= 50- � r + --+—{ 851.32c J J J J J J J J J J L L + r I r r I r r NRCC I24»hrB - yr-2-4-hrRa nfaif=LG4"- Runoff Area=78.800 ac J J I I unaff Vorunee=103.601-if - Ru fofF Dc pt11-=4 40" - Tc=30 ' mien L CN=95 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 55 Summary for Subcatchment B2.U: DA B2.0 Runoff = 56.73 cfs @ 12.44 hrs, Volume= 6.454 af, Depth= 2.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 33.500 73 33.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 60-' 55--� 50--/ 45- u 35-/ 0 30- / LL25_ 20_ 15_' 5- Direct Entry, Subcatchment B2.U: DA B2.0 Hydrograph 56.73 cfs NR C1124»-r 4N R`C --11 yr-24t'tr Rair,`ifall=$.O4" - 1*tunof#-Arrea-33.-500 ac - Runoff Vollun><e=6.454-if _ 1_ Runoff Doptti=Z.31"_ Tc=30.0�� min CN=73 8 10 12 14 16 18 20 22 24 26 28 30 Time (hours) 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 56 Summary for Subcatchment B3.U: DA B3.0 Runoff = 88.85 cfs @ 12.44 hrs, Volume= 10.263 af, Depth= 1.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description 62.000 69 62.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 95� 90= 85=-� 80 75 70= 65" 60='� u 55 3 50 2 45 u_ 40" 35 30" 25=- - 20 15 — 10" - 5 Direct Entry, Subcatchment B3.U: DA B3.0 Hydrograph 1 818.85 cfs 1 + + 1 1 :r + r NRCC 2441rB- NRCC-1Qyr-24hr Rainfall=6.04" + 7 1 1 1 i L turlofi-Arrea=2.000 ac - Runoff iidlu d=10263-af- 4 4 1 1 r 1 1 r Runoff Doptth=1.99"„ = 4 4 1 1 ic=3G.O-min — 4- = CN=6g +--+--+ + r r ri r r r r + + + I r Y Y r 1 1 1 I 1 T 1 1 1 8 10 12 14 16 18 20 22 24 26 28 30 Time (hours) 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 57 Summary for Subcatchment C1: C1-A Runoff = 1,527.46 cfs @ 12.41 hrs, Volume= 178.864 af, Depth= 4.02" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 533.800 91 533.800 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Subcatchment C1: C1-A Hydrograph 1,700 1,6001: 1,500�� 1,400� 1,3007- 1,200L:- 1,000- 900- 800- " 700 600J 500- 400= 300= 200= 100- 0 L 1 1,527.46 cfs a� + r i + + + — I — —I + + ▪ L I I J J r r ▪ NRCC_ J J NRCC 24-hr 13 ▪ T I I + + 10yr-24fhr Rairlfallll=_L.94" Runoff -Jkrea= 33.$O ac - Runoff Votunie=178 864-af - 14urtoff+DeptM=4.ff-" min CIS=91 7 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 58 Summary for Subcatchment C2.U: DA C2.0 Runoff = 249.95 cfs @ 12.70 hrs, Volume= 37.847 af, Depth= 2.48" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 183.000 75 183.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 50.0 Direct Entry, Subcatchment C2.U: DA C2.0 Hydrograph 260- 240— 220J 200- 180� w 160- 3 140— a 120�� T 100- 80= 60- 40- 20� 0 ✓ + 4 ▪ r + r r ✓ r T r ▪ 1 1 L t r-• _-� rt t r 8 10 12 NRQC 14 16 18 20 22 24 26 28 30 Time (hours) NR C-24.hrB- - fGy r-24hr Ra' d ai F=$ G4" - Rurroff-Are a 183 000 ac - Runoff VbFuthe '37- 847-af - fZurlofFDepth= 4 - 1 L Trt =50 -O- - 32 34 36 38 40 42 44 46 48 • Runoff ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 59 Summary for Subcatchment C3.U: DA C3.0 Runoff = 211.17 cfs @ 12.64 hrs, Volume= 30.162 af, Depth= 2.23" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Area (ac) CN Description * 162.400 72 162.400 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 45.0 Direct Entry, Subcatchment C3.U: DA C3.0 Hydrograph ▪ 71 230� I 220-' z k + - 211.17 cfs 210:-/ r I I 1 7 r 200;'" 1 1 + T 190-='-------+ + + 180+:" 170' 1 1 1 160� ,1— —I —+ —+ 150� 140�' L I I 1 1 1 w 130= I I + + + 120-:" zz 0 110= 1 1 • 100: T , T r 90/ I 80- ' I I -4 -4 70= ▪ - - 7 r 60= 50- 40 30 20- 10- 0 7 7 7 T r r 7 I I 4 41 T T + ; + T 14RRC-I24.hr4B- + + +--+- NRICc1Qyr-2411rRairtfal=_L.04„ RunOff-i4i ea=46.A60-ac L L I I I 1 1 1 1 L 1 +---------Ruhuftubrukne*30.162-af- T 1 1 L T Furtoff-Deptl17=2 31• - 1 1 1 1 I I I 1 1 L 7 4 T r I I I 7 r r C N=7+2 4 T + + I I I -4 + 4- I I I 4 + 7 4 T r I I I 7 r T I I I 4 T +--I--+ H + + + + I I % 1 7 T I - 4 T r I I 1 r r I I I 4 T + ,+ + — — + — — + + — — — — + — — + I I I + — — + — — + I I I + — — + 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) • Runoff ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 60 Inflow Area = Inflow = Outflow = Primary = Summary for Pond Pond A3: Pond A3 224.600 ac, 0.00% Impervious, Inflow Depth = 4.41" for NRCC-10yr-24hr event 775.28 cfs @ 12.31 hrs, Volume= 82.536 af 194.81 cfs @ 12.90 hrs, Volume= 72.563 af, Atten= 75%, Lag= 35.0 min 194.81 cfs @ 12.90 hrs, Volume= 72.563 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 678.00' Surf.Area= 168,544 sf Storage= 781,799 cf Peak Elev= 687.28' @ 12.90 hrs Surf.Area= 223,083 sf Storage= 2,612,029 cf (1,830,230 cf above start) Plug -Flow detention time= 337.1 min calculated for 54.615 af (66% of inflow) Center -of -Mass det. time= 172.8 min (959.4 - 786.5 ) Volume Invert Avail.Storage Storage Description #1 Elevation (feet) 672.00 674.00 676.00 678.00 680.00 682.00 684.00 686.00 688.00 690.00 692.00 672.00' 3,727,860 cf Custom Stage Data (Prismatic)Listed below (Recalc) Device Routing Surf.Area (sq-ft) 99,117 113,009 144,060 168,544 183,296 193,916 204,761 215,830 227,123 238,641 250,383 Invert Inc.Store (cubic -feet) 0 212,126 257,069 312,604 351,840 377,212 398,677 420,591 442,953 465,764 489,024 Outlet Devices Cum.Store (cubic -feet) 0 212,126 469,195 781,799 1,133,639 1,510,851 1,909,528 2,330,119 2,773,072 3,238,836 3,727,860 #1 Primary #2 #3 #4 Device 1 Device 1 Device 1 672.00' 678.00' 688.00' 681.00' 60.0" Round Culvert L= 414.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 672.00' / 670.00' S= 0.0048'/' Cc= 0.900 n= 0.013, Flow Area= 19.63 sf 6.0" Vert. Orifice/Grate C= 0.600 40.0' long Sharp -Crested Rectangular Weir 0 End Contraction(s) 54.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=194.81 cfs @ 12.90 hrs HW=687.28' (Free Discharge) 4-1=Culvert (Passes 194.81 cfs of 317.73 cfs potential flow) - 2=Orifice/Grate (Orifice Controls 2.84 cfs @ 14.47 fps) - 3=Sharp-Crested Rectangular Weir( Controls 0.00 cfs) -4=Orifice/Grate (Orifice Controls 191.97 cfs @ 12.07 fps) ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC U 0 LL Elevation (feet) 850- 800J 750J 700" 650� 600� 5501_" 5001: 450� 400- 350- 300� 250- 200- 150= 100� 775.28 cf 194.81 50J0 A- L r L L Pond Pond A3: Pond A3 Hyd rog raph 7 r r - h -r 4 L 1 L ✓ 69 69 69 68 68 68 68 68 68 68 68 68 68 67 67 67 67 67 67 67 67 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 61 inflow Putat=224 600 ac ✓ --t--r----r--tr----r--r PeaM- rev=6$7;28-'-- J 1 L I 1 1 L I 1 L Storage=2,612,029 cf 1 L ✓ Y r 7 r L ✓ r r ✓ 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Pond Pond A3: Pond A3 Stage -Discharge ✓ r r r Shjp-Crested Rectangular Weir 5r-' L L L L L - z 4L L�///� L L L 3�� L L I 2� ���Orifice/Gra L L L L % 4- L L L L 0- % L L 9 - - - Orifice/Grate L L 8 r 7�% r I r 6�% 5 r ✓ L L r r r r r r r L 4-4- 0 50 100 150 200 Discharge (cfs) 250 300 350 C Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 692-' 691- 690 689J 688 687 686 685 684 0 682J 681 w 680- 679J 678 677 676= 675- 674� 673 672 Pond Pond A3: Pond A3 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 62 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 200,000 220,000 240,000 I'''I 'III I'''I'II J 1 J L 11 J + 1 1 L J JI I 11 JI 11 IL 1 -II 1 11 11 L /_ - - 1 1 ----+---1-_1 1 r----a+ 1 z/-t---- 11 1 1 11 1 II 1 JI 1 IL 11 J //��, IL JI 1 r 1+ + 1 r 1 r 1 1 r n r 1 1 r r r1 Custom Stage Data 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000 3,500,000 Storage (cubic -feet) u Surface • Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 63 Stage -Discharge for Pond Pond A3: Pond A3 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 672.00 0.00 682.40 78.50 672.20 0.00 682.60 95.53 672.40 0.00 682.80 104.76 672.60 0.00 683.00 110.36 672.80 0.00 683.20 115.69 673.00 0.00 683.40 120.78 673.20 0.00 683.60 125.67 673.40 0.00 683.80 130.37 673.60 0.00 684.00 134.91 673.80 0.00 684.20 139.29 674.00 0.00 684.40 143.55 674.20 0.00 684.60 147.68 674.40 0.00 684.80 151.70 674.60 0.00 685.00 155.61 674.80 0.00 685.20 159.43 675.00 0.00 685.40 163.16 675.20 0.00 685.60 166.81 675.40 0.00 685.80 170.37 675.60 0.00 686.00 173.87 675.80 0.00 686.20 177.29 676.00 0.00 686.40 180.65 676.20 0.00 686.60 183.95 676.40 0.00 686.80 187.19 676.60 0.00 687.00 190.38 676.80 0.00 687.20 193.51 677.00 0.00 687.40 196.59 677.20 0.00 687.60 199.63 677.40 0.00 687.80 202.61 677.60 0.00 688.00 205.56 677.80 0.00 688.20 220.16 678.00 0.00 688.40 244.42 678.20 0.11 688.60 274.95 678.40 0.36 688.80 310.54 678.60 0.56 689.00 339.20 678.80 0.70 689.20 341.61 679.00 0.82 689.40 344.01 679.20 0.92 689.60 346.39 679.40 1.01 689.80 348.75 679.60 1.10 690.00 351.10 679.80 1.18 690.20 353.43 680.00 1.25 690.40 355.75 680.20 1.32 690.60 358.05 680.40 1.39 690.80 360.34 680.60 1.45 691.00 362.62 680.80 1.51 691.20 364.88 681.00 1.57 691.40 367.12 681.20 5.76 691.60 369.35 681.40 13.37 691.80 371.57 681.60 23.22 692.00 373.78 681.80 34.86 682.00 48.06 682.20 62.65 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 64 Stage -Area -Storage for Pond Pond A3: Pond A3 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 672.00 99,117 0 682.40 196,085 1,588,851 672.20 100,506 19,962 682.60 197,170 1,628,177 672.40 101,895 40,202 682.80 198,254 1,667,719 672.60 103,285 60,720 683.00 199,339 1,707,478 672.80 104,674 81,516 683.20 200,423 1,747,454 673.00 106,063 102,590 683.40 201,507 1,787,647 673.20 107,452 123,942 683.60 202,592 1,828,057 673.40 108,841 145,571 683.80 203,676 1,868,684 673.60 110,231 167,478 684.00 204,761 1,909,528 673.80 111,620 189,663 684.20 205,868 1,950,591 674.00 113,009 212,126 684.40 206,975 1,991,875 674.20 116,114 235,038 684.60 208,082 2,033,381 674.40 119,219 258,572 684.80 209,189 2,075,108 674.60 122,324 282,726 685.00 210,296 2,117,056 674.80 125,429 307,501 685.20 211,402 2,159,226 675.00 128,535 332,898 685.40 212,509 2,201,617 675.20 131,640 358,915 685.60 213,616 2,244,230 675.40 134,745 385,554 685.80 214,723 2,287,064 675.60 137,850 412,813 686.00 215,830 2,330,119 675.80 140,955 440,694 686.20 216,959 2,373,398 676.00 144,060 469,195 686.40 218,089 2,416,903 676.20 146,508 498,252 686.60 219,218 2,460,633 676.40 148,957 527,798 686.80 220,347 2,504,590 676.60 151,405 557,835 687.00 221,477 2,548,772 676.80 153,854 588,360 687.20 222,606 2,593,180 677.00 156,302 619,376 687.40 223,735 2,637,815 677.20 158,750 650,881 687.60 224,864 2,682,675 677.40 161,199 682,876 687.80 225,994 2,727,760 677.60 163,647 715,361 688.00 227,123 2,773,072 677.80 166,096 748,335 688.20 228,275 2,818,612 678.00 168,544 781,799 688.40 229,427 2,864,382 678.20 170,019 815,655 688.60 230,578 2,910,382 678.40 171,494 849,807 688.80 231,730 2,956,613 678.60 172,970 884,253 689.00 232,882 3,003,075 678.80 174,445 918,995 689.20 234,034 3,049,766 679.00 175,920 954,031 689.40 235,186 3,096,688 679.20 177,395 989,363 689.60 236,337 3,143,840 679.40 178,870 1,024,989 689.80 237,489 3,191,223 679.60 180,346 1,060,911 690.00 238,641 3,238,836 679.80 181,821 1,097,127 690.20 239,815 3,286,682 680.00 183,296 1,133,639 690.40 240,989 3,334,762 680.20 184,358 1,170,404 690.60 242,164 3,383,077 680.40 185,420 1,207,382 690.80 243,338 3,431,628 680.60 186,482 1,244,572 691.00 244,512 3,480,413 680.80 187,544 1,281,975 691.20 245,686 3,529,432 681.00 188,606 1,319,590 691.40 246,860 3,578,687 681.20 189,668 1,357,417 691.60 248,035 3,628,176 681.40 190,730 1,395,457 691.80 249,209 3,677,901 681.60 191,792 1,433,709 692.00 250,383 3,727,860 681.80 192,854 1,472,174 682.00 193,916 1,510,851 682.20 195,001 1,549,743 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 65 Summary for Pond Pond B1: Pond B1 Inflow Area = 278.800 ac, 0.00% Impervious, Inflow Depth = 4.46" for NRCC-10yr-24hr event Inflow = 851.32 cfs @ 12.41 hrs, Volume= 103.601 af Outflow = 387.61 cfs @ 12.82 hrs, Volume= 103.491 af, Atten= 54%, Lag= 24.9 min Primary = 387.61 cfs @ 12.82 hrs, Volume= 103.491 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 683.88' @ 12.82 hrs Surf.Area= 275,063 sf Storage= 1,346,008 cf Plug -Flow detention time= 67.2 min calculated for 103.383 af (100% of inflow) Center -of -Mass det. time= 67.6 min (858.5 - 790.9 ) Volume Invert Avail.Storage Storage Description #1 676.00' 2,737,543 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 676.00 75,404 0 0 678.00 120,832 196,236 196,236 680.00 169,974 290,806 487,042 682.00 222,421 392,395 879,437 684.00 278,551 500,972 1,380,409 686.00 338,363 616,914 1,997,323 688.00 401,857 740,220 2,737,543 Device Routing Invert Outlet Devices #1 Primary 676.00' 84.0" Round Culvert L= 711.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 676.00' / 617.00' S= 0.0830'/' Cc= 0.900 n= 0.013, Flow Area= 38.48 sf Primary OutFlow Max=387.45 cfs @ 12.82 hrs HW=683.87' (Free Discharge) 4-1=Culvert (Inlet Controls 387.45 cfs @ 10.07 fps) ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 0 LL Elevation (feet) 950- 900J 850 800 750 700 650� 600J 5507:' 500 450� 400� 350- 300� 250= 200� 1504' 100� 50- 0 Pond Pond B1: Pond B1 Hyd rog raph NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 66 1 851.32 cfs I 387.61 cfs - r r T r I 1 T r I 1 r 1 T T r 1 r T r 1 T T 1 err low Area=2-78.8Q01r ac - Paik aev=b$3;88-' Storagre=111,346,008-cf - 84.O Rgiind Civet- n=10.0T3 L 1 1 Li= I 1 . Cr- - 1 L 1 1 L 1 5=0111-0$-3O'i' 1 1 l 11 0 688- 687J 686-' 685J 684� 683� 682� 681-� 680-- 679- z 678-- 677- 676 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Time (hours) Pond Pond B1: Pond B1 Stage -Discharge T Ti 1 + 1 1 + 1 ✓ + L ✓ + L Ti 1 + 1 1 + ▪ T -4 0 50 100 150 200 250 300 Discharge (cfs) ✓ + L + L + 4- 40 42 44 46 48 T r L T L r 350 400 450 500 i 1 D Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 688 687J 686- 6851- 684- w 6831' I682Y - 681:� w 680- 6791" 678 677- Pond Pond B1: Pond B1 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft, 50,000 100,000 150,000 200,000 250,000 300,000 350,000 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 67 400,000 T 4 Custom Stage Dati 676 0 500,000 1,000,000 1,500,000 Storage (cubic -feet) 2,000,000 2,500,000 • Surface` • Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 68 Stage -Discharge for Pond Pond B1: Pond B1 Elevation Primary Elevation Primary Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) (feet) (cfs) (feet) (cfs) 676.00 0.00 679.12 99.76 682.24 308.09 685.36 448.57 676.06 0.04 679.18 103.25 682.30 311.76 685.42 450.86 676.12 0.17 679.24 106.78 682.36 315.37 685.48 453.14 676.18 0.39 679.30 110.36 682.42 318.89 685.54 455.41 676.24 0.68 679.36 113.97 682.48 322.34 685.60 457.66 676.30 1.07 679.42 117.63 682.54 325.69 685.66 459.91 676.36 1.53 679.48 121.33 682.60 328.95 685.72 462.14 676.42 2.08 679.54 125.06 682.66 332.09 685.78 464.37 676.48 2.71 679.60 128.83 682.72 335.11 685.84 466.58 676.54 3.42 679.66 132.63 682.78 337.98 685.90 468.78 676.60 4.21 679.72 136.47 682.84 340.69 685.96 470.97 676.66 5.08 679.78 140.33 682.90 343.19 686.02 473.16 676.72 6.03 679.84 144.23 682.96 345.42 686.08 475.33 676.78 7.06 679.90 148.17 683.02 347.66 686.14 477.49 676.84 8.16 679.96 152.12 683.08 350.61 686.20 479.64 676.90 9.34 680.02 156.11 683.14 353.53 686.26 481.79 676.96 10.60 680.08 160.13 683.20 356.44 686.32 483.92 677.02 11.93 680.14 164.16 683.26 359.31 686.38 486.04 677.08 13.34 680.20 168.22 683.32 362.17 686.44 488.16 677.14 14.82 680.26 172.31 683.38 365.00 686.50 490.26 677.20 16.38 680.32 176.41 683.44 367.81 686.56 492.36 677.26 18.00 680.38 180.54 683.50 370.60 686.62 494.45 677.32 19.70 680.44 184.68 683.56 373.37 686.68 496.53 677.38 21.47 680.50 188.84 683.62 376.12 686.74 498.60 677.44 23.31 680.56 193.01 683.68 378.85 686.80 500.66 677.50 25.21 680.62 197.20 683.74 381.56 686.86 502.71 677.56 27.19 680.68 201.39 683.80 384.25 686.92 504.76 677.62 29.23 680.74 205.60 683.86 386.92 686.98 506.79 677.68 31.34 680.80 209.82 683.92 389.58 687.04 508.82 677.74 33.52 680.86 214.04 683.98 392.21 687.10 510.84 677.80 35.76 680.92 218.27 684.04 394.83 687.16 512.85 677.86 38.06 680.98 222.50 684.10 397.43 687.22 514.86 677.92 40.43 681.04 226.73 684.16 400.01 687.28 516.86 677.98 42.86 681.10 230.97 684.22 402.58 687.34 518.85 678.04 45.36 681.16 235.20 684.28 405.13 687.40 520.83 678.10 47.91 681.22 239.42 684.34 407.66 687.46 522.80 678.16 50.52 681.28 243.64 684.40 410.18 687.52 524.77 678.22 53.20 681.34 247.85 684.46 412.69 687.58 526.73 678.28 55.93 681.40 252.04 684.52 415.18 687.64 528.68 678.34 58.71 681.46 256.23 684.58 417.65 687.70 530.62 678.40 61.56 681.52 260.39 684.64 420.11 687.76 532.56 678.46 64.46 681.58 264.54 684.70 422.55 687.82 534.49 678.52 67.41 681.64 268.67 684.76 424.98 687.88 536.42 678.58 70.42 681.70 272.78 684.82 427.40 687.94 538.33 678.64 73.48 681.76 276.85 684.88 429.80 688.00 540.24 678.70 76.60 681.82 280.90 684.94 432.19 678.76 79.76 681.88 284.91 685.00 434.57 678.82 82.97 681.94 288.89 685.06 436.94 678.88 86.24 682.00 292.83 685.12 439.29 678.94 89.55 682.06 296.72 685.18 441.63 679.00 92.90 682.12 300.56 685.24 443.95 679.06 96.31 682.18 304.36 685.30 446.27 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 69 Stage -Area -Storage for Pond Pond B1: Pond B1 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 676.00 75,404 0 683.80 272,938 1,325,260 676.15 78,811 11,566 683.95 277,148 1,366,517 676.30 82,218 23,643 684.10 281,542 1,408,414 676.45 85,625 36,232 684.25 286,028 1,450,981 676.60 89,032 49,331 684.40 290,513 1,494,222 676.75 92,440 62,941 684.55 294,999 1,538,135 676.90 95,847 77,063 684.70 299,485 1,582,722 677.05 99,254 91,695 684.85 303,971 1,627,981 677.20 102,661 106,839 685.00 308,457 1,673,913 677.35 106,068 122,494 685.15 312,943 1,720,518 677.50 109,475 138,659 685.30 317,429 1,767,796 677.65 112,882 155,336 685.45 321,915 1,815,747 677.80 116,289 172,524 685.60 326,401 1,864,370 677.95 119,696 190,223 685.75 330,887 1,913,667 678.10 123,289 208,442 685.90 335,372 1,963,636 678.25 126,975 227,212 686.05 339,950 2,014,281 678.40 130,660 246,534 686.20 344,712 2,065,631 678.55 134,346 266,410 686.35 349,474 2,117,695 678.70 138,032 286,838 686.50 354,237 2,170,473 678.85 141,717 307,819 686.65 358,999 2,223,966 679.00 145,403 329,354 686.80 363,761 2,278,172 679.15 149,089 351,440 686.95 368,523 2,333,094 679.30 152,774 374,080 687.10 373,285 2,388,729 679.45 156,460 397,273 687.25 378,047 2,445,079 679.60 160,146 421,018 687.40 382,809 2,502,143 679.75 163,831 445,316 687.55 387,571 2,559,922 679.90 167,517 470,167 687.70 392,333 2,618,415 680.05 171,285 495,573 687.85 397,095 2,677,622 680.20 175,219 521,561 688.00 401,857 2,737,543 680.35 179,152 548,139 680.50 183,086 575,307 680.65 187,019 603,065 680.80 190,953 631,413 680.95 194,886 660,351 681.10 198,820 689,879 681.25 202,753 719,997 681.40 206,687 750,705 681.55 210,620 782,003 681.70 214,554 813,891 681.85 218,487 846,369 682.00 222,421 879,437 682.15 226,631 913,116 682.30 230,840 947,426 682.45 235,050 982,368 682.60 239,260 1,017,941 682.75 243,470 1,054,146 682.90 247,679 1,090,982 683.05 251,889 1,128,450 683.20 256,099 1,166,549 683.35 260,309 1,205,280 683.50 264,519 1,244,642 683.65 268,728 1,284,635 ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 70 Summary for Pond Pond B2: Pond B2 [79] Warning: Submerged Pond Pond B1 Primary device # 1 OUTLET by 2.10' Inflow Area = Inflow = Outflow = Primary = 278.800 ac, 0.00% Impervious, Inflow Depth > 4.45" for NRCC-10yr-24hr event 387.61 cfs @ 12.82 hrs, Volume= 103.491 af 330.59 cfs @ 13.44 hrs, Volume= 90.491 af, Atten= 15%, Lag= 37.3 min 330.59 cfs @ 13.44 hrs, Volume= 90.491 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 614.00' Surf.Area= 213,648 sf Storage= 1,110,739 cf Peak Elev= 619.10' @ 13.44 hrs Surf.Area= 250,417 sf Storage= 2,304,541 cf (1,193,802 cf above start) Plug -Flow detention time= 310.9 min calculated for 64.992 af (63% of inflow) Center -of -Mass det. time= 116.0 min (974.5 - 858.5 ) Volume Invert Avail.Storage Storage Description #1 Elevation (feet) 608.00 610.00 612.00 616.00 618.00 620.00 622.00 608.00' 3,055,722 cf Custom Stage Data (Prismatic)Listed below (Recalc) Device Routing Surf.Area (sq-ft) 148,967 178,807 195,255 232,041 243,810 255,804 268,025 Invert Inc.Store (cubic -feet) 0 327,774 374,062 854,592 475,851 499,614 523,829 Outlet Devices Cum.Store (cubic -feet) 0 327,774 701,836 1,556,428 2,032,279 2,531,893 3,055,722 #1 Primary #2 Device 1 #3 Device 1 608.00' 614.00' 617.00' 66.0" Round Culvert L= 280.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 608.00' / 604.00' S= 0.0143'/' Cc= 0.900 n= 0.013, Flow Area= 23.76 sf 7.0" Vert. Orifice/Grate C= 0.600 40.0' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=330.59 cfs @ 13.44 hrs HW=619.10' (Free Discharge) 4-1=Culvert (Inlet Controls 330.59 cfs @ 13.91 fps) AL2=Orifice/Grate (Passes < 2.82 cfs potential flow) 3=Sharp-Crested Rectangular Weir(Passes < 398.48 cfs potential flow) ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 71 420J 400 380J 360J 340J 320 300 280 260 ,3 240 220� 0 200= • 180= 160= 140i- 120= 100= 80- 60- 40 20 0 4 0 330.59 cfs Pond Pond B2: Pond B2 Hyd rog raph +--+-----I--+--+-------+------+-_+--+--I--+--+-_+--I--+--+--I II II 1387.61 cfs 1 4- L 1 L J L 8 10 12 14 r Inflow -JArea=2-7 81001E ac 1 L I J 1 L J IL 1 L I 1 + L I 1 + L I 1 1 L I 1 I J 1- r i L 1 L 1 J 1 IL J L IL 1 L + L i J + L -1 L L 1 L i r J L r i L Lr r I J L r 1 L Lr r I J L r 1 L 1 LI 1 L LI L L i 1 16 18 20 22 24 26 28 30 32 34 36 38 Time (hours) Pond Pond B2: Pond B2 Stage -Discharge L 40 42 44 46 48 622/ 621 ' 620" 6191" 618��� 617 w 616 0 615 w • 614 w 613 612 611 610 609 608 Sharp -Crested Rectangular Weir Orifice/rate r 1 1 L + ✓ 1 + 1 L 0 50 100 150 200 Discharge (cfs) 250 300 350 IN Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 72 Elevation (feet) Pond Pond B2: Pond B2 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000180,000 200,000 220,000240,000 260,000 622_ I I I I I I LIr r II 621_ -----Ir + + + r + r rr 620� I I 619- 618- 617- 616- 615- 614- zz 613- 612= 611 610- 609= Custom Stage Data 608 0 IL 500,000 ri -II I I I r r-r--r----r--r-r----r---rr 1,000,000 41 r ' r r r r --Irr 1,500,000 2,000,000 Storage (cubic -feet) 2,500,000 3,000,000 Surface ❑ Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 ©2019 HydroCAD Software Solutions LLC Page 73 Stage -Discharge for Pond Pond B2: Pond B2 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 608.00 0.00 615.80 1.58 608.15 0.00 615.95 1.66 608.30 0.00 616.10 1.73 608.45 0.00 616.25 1.80 608.60 0.00 616.40 1.87 608.75 0.00 616.55 1.93 608.90 0.00 616.70 2.00 609.05 0.00 616.85 2.06 609.20 0.00 617.00 2.12 609.35 0.00 617.15 9.77 609.50 0.00 617.30 23.72 609.65 0.00 617.45 41.77 609.80 0.00 617.60 63.13 609.95 0.00 617.75 87.35 610.10 0.00 617.90 114.12 610.25 0.00 618.05 143.23 610.40 0.00 618.20 174.49 610.55 0.00 618.35 207.76 610.70 0.00 618.50 242.93 610.85 0.00 618.65 279.91 611.00 0.00 618.80 318.61 611.15 0.00 618.95 327.58 611.30 0.00 619.10 330.56 611.45 0.00 619.25 333.52 611.60 0.00 619.40 336.45 611.75 0.00 619.55 339.35 611.90 0.00 619.70 342.23 612.05 0.00 619.85 345.09 612.20 0.00 620.00 347.92 612.35 0.00 620.15 350.73 612.50 0.00 620.30 353.52 612.65 0.00 620.45 356.28 612.80 0.00 620.60 359.03 612.95 0.00 620.75 361.75 613.10 0.00 620.90 364.45 613.25 0.00 621.05 367.14 613.40 0.00 621.20 369.80 613.55 0.00 621.35 372.45 613.70 0.00 621.50 375.07 613.85 0.00 621.65 377.68 614.00 0.00 621.80 380.27 614.15 0.07 621.95 382.84 614.30 0.26 614.45 0.51 614.60 0.71 614.75 0.87 614.90 1.00 615.05 1.12 615.20 1.23 615.35 1.32 615.50 1.41 615.65 1.50 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 74 Stage -Area -Storage for Pond Pond B2: Pond B2 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 608.00 148,967 0 615.80 230,202 1,510,204 608.15 151,205 22,513 615.95 231,581 1,544,837 608.30 153,443 45,361 616.10 232,629 1,579,662 608.45 155,681 68,546 616.25 233,512 1,614,622 608.60 157,919 92,066 616.40 234,395 1,649,715 608.75 160,157 115,922 616.55 235,277 1,684,941 608.90 162,395 140,113 616.70 236,160 1,720,298 609.05 164,633 164,640 616.85 237,043 1,755,789 609.20 166,871 189,503 617.00 237,926 1,791,411 609.35 169,109 214,701 617.15 238,808 1,827,166 609.50 171,347 240,236 617.30 239,691 1,863,054 609.65 173,585 266,105 617.45 240,574 1,899,074 609.80 175,823 292,311 617.60 241,456 1,935,226 609.95 178,061 318,852 617.75 242,339 1,971,510 610.10 179,629 345,696 617.90 243,222 2,007,927 610.25 180,863 372,733 618.05 244,110 2,044,477 610.40 182,097 399,955 618.20 245,009 2,081,161 610.55 183,330 427,362 618.35 245,909 2,117,980 610.70 184,564 454,954 618.50 246,809 2,154,934 610.85 185,797 482,731 618.65 247,708 2,192,022 611.00 187,031 510,693 618.80 248,608 2,229,246 611.15 188,265 538,840 618.95 249,507 2,266,605 611.30 189,498 567,172 619.10 250,407 2,304,098 611.45 190,732 595,690 619.25 251,306 2,341,727 611.60 191,965 624,392 619.40 252,206 2,379,490 611.75 193,199 653,279 619.55 253,105 2,417,388 611.90 194,433 682,352 619.70 254,005 2,455,422 612.05 195,715 711,610 619.85 254,904 2,493,590 612.20 197,094 741,071 620.00 255,804 2,531,893 612.35 198,474 770,739 620.15 256,721 2,570,332 612.50 199,853 800,613 620.30 257,637 2,608,909 612.65 201,233 830,695 620.45 258,554 2,647,623 612.80 202,612 860,983 620.60 259,470 2,686,475 612.95 203,992 891,478 620.75 260,387 2,725,465 613.10 205,371 922,180 620.90 261,303 2,764,591 613.25 206,751 953,090 621.05 262,220 2,803,856 613.40 208,130 984,206 621.20 263,137 2,843,257 613.55 209,510 1,015,529 621.35 264,053 2,882,797 613.70 210,889 1,047,058 621.50 264,970 2,922,473 613.85 212,269 1,078,795 621.65 265,886 2,962,288 614.00 213,648 1,110,739 621.80 266,803 3,002,239 614.15 215,027 1,142,890 621.95 267,719 3,042,328 614.30 216,407 1,175,247 614.45 217,786 1,207,812 614.60 219,166 1,240,583 614.75 220,545 1,273,562 614.90 221,925 1,306,747 615.05 223,304 1,340,139 615.20 224,684 1,373,738 615.35 226,063 1,407,544 615.50 227,443 1,441,557 615.65 228,822 1,475,777 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 75 Summary for Pond Pond C1: Pond C1 Inflow Area = 533.800 ac, 0.00% Impervious, Inflow Depth = 4.02" for NRCC-10yr-24hr event Inflow = 1,527.46 cfs @ 12.41 hrs, Volume= 178.864 of Outflow = 443.22 cfs @ 13.05 hrs, Volume= 176.812 af, Atten= 71%, Lag= 38.1 min Primary = 443.22 cfs @ 13.05 hrs, Volume= 176.812 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 675.47' @ 13.05 hrs Surf.Area= 362,989 sf Storage= 3,224,204 cf Plug -Flow detention time= 117.9 min calculated for 176.628 af (99% of inflow) Center -of -Mass det. time= 111.7 min (921.1 - 809.4 ) Volume Invert Avail.Storage Storage Description #1 664.00' 6,161,365 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 664.00 49,861 0 0 665.00 106,320 78,091 78,091 668.00 311,540 626,790 704,881 670.00 324,958 636,498 1,341,379 675.00 359,560 1,711,295 3,052,674 680.00 395,673 1,888,083 4,940,756 683.00 418,066 1,220,609 6,161,365 Device Routing Invert Outlet Devices #1 Primary 665.00' 72.0" Round Culvert L= 991.0' RCP, groove end w/headwall, Ke= 0.200 Inlet / Outlet Invert= 665.00' / 654.00' S= 0.0111 '/' Cc= 0.900 n= 0.013, Flow Area= 28.27 sf Primary OutFlow Max=443.21 cfs @ 13.05 hrs HW=675.47' (Free Discharge) 4-1=Culvert (Barrel Controls 443.21 cfs @ 15.68 fps) ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 76 Pond Pond C1: Pond C1 Hyd rog raph 1,700 1,6004 1,5004 1,4004-'1 �L 1, 300� 1,200- 1,1004/ 1, 000� • 900J 0 8004 / L LT_ 700J 600� 5004 4004 3004 - r 200 1004 0 Elevation (feet) + —r L L r 4 r 1,527.46 cfs L v 1- L ✓ L + L ▪ 41 1 + --+--I--+--+--I--+--r--I 1 1 L I 1 L I 1 L I Inflow o Area$533.800-ac Peaty 1ev=6/5.4 r r I r r I r r I Storage=3,224,204-c',f - 1 L 1 72 0" — 1T r r r Fkau rid- C lve t- + n=9.-013 L=991.0 S=0,0111 hi' r r 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Pond Pond C1: Pond C1 Stage -Discharge 683 _ 682� 6814/- 6804 679L. + 678� 677=- 676— 675— )_ 674- 673=' 672= 6714 670- 1 669 1 668��_ 6674 666: ---- Culver; 665 664 T r r ✓ 4- • r -r r 4 r 4 L L 0 50 100 150 200 250 300 Discharge (cfs) 350 400 450 500 C Inflow ❑ Primary • Primary` ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Elevation (feet) 683 682� 681- z 680 679 678J 677 676 675 674J 673 672J 671= 670 669 668 667' 666 665 664 0 Pond Pond C1: Pond C1 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 77 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 I I I ' I I I 1 I 1,000,000 2,000,000 1 ri 1i 3,000,000 4,000,000 Storage (cubic -feet) L 5,000,000 6,000,000 Surface ❑ Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 78 Stage -Discharge for Pond Pond Cl: Pond C1 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 664.00 0.00 674.40 427.55 664.20 0.00 674.60 430.51 664.40 0.00 674.80 433.45 664.60 0.00 675.00 436.37 664.80 0.00 675.20 439.27 665.00 0.00 675.40 442.15 665.20 0.48 675.60 445.01 665.40 2.12 675.80 447.86 665.60 4.85 676.00 450.68 665.80 8.53 676.20 453.49 666.00 13.18 676.40 456.28 666.20 18.77 676.60 459.05 666.40 25.25 676.80 461.81 666.60 32.58 677.00 464.55 666.80 40.73 677.20 467.28 667.00 49.66 677.40 469.98 667.20 59.30 677.60 472.68 667.40 69.63 677.80 475.36 667.60 80.59 678.00 478.02 667.80 92.14 678.20 480.67 668.00 104.21 678.40 483.30 668.20 116.76 678.60 485.92 668.40 129.72 678.80 488.53 668.60 143.03 679.00 491.12 668.80 156.63 679.20 493.70 669.00 170.44 679.40 496.26 669.20 184.38 679.60 498.81 669.40 198.38 679.80 501.35 669.60 212.32 680.00 503.88 669.80 226.10 680.20 506.39 670.00 239.59 680.40 508.89 670.20 252.65 680.60 511.38 670.40 265.07 680.80 513.86 670.60 276.61 681.00 516.32 670.80 286.83 681.20 518.77 671.00 294.75 681.40 521.21 671.20 304.42 681.60 523.64 671.40 313.79 681.80 526.06 671.60 322.88 682.00 528.47 671.80 331.73 682.20 530.87 672.00 340.35 682.40 533.25 672.20 348.76 682.60 535.63 672.40 356.96 682.80 537.99 672.60 364.99 683.00 540.35 672.80 372.84 673.00 380.52 673.20 388.06 673.40 395.45 673.60 402.71 673.80 409.84 674.00 416.84 674.20 423.73 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 79 Stage -Area -Storage for Pond Pond Cl: Pond C1 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 664.00 49,861 0 674.40 355,408 2,838,183 664.20 61,153 11,101 674.60 356,792 2,909,403 664.40 72,445 24,461 674.80 358,176 2,980,900 664.60 83,736 40,079 675.00 359,560 3,052,674 664.80 95,028 57,956 675.20 361,005 3,124,730 665.00 106,320 78,091 675.40 362,449 3,197,075 665.20 120,001 100,723 675.60 363,894 3,269,710 665.40 133,683 126,091 675.80 365,338 3,342,633 665.60 147,364 154,196 676.00 366,783 3,415,845 665.80 161,045 185,037 676.20 368,227 3,489,346 666.00 174,727 218,614 676.40 369,672 3,563,136 666.20 188,408 254,927 676.60 371,116 3,637,214 666.40 202,089 293,977 676.80 372,561 3,711,582 666.60 215,771 335,763 677.00 374,005 3,786,239 666.80 229,452 380,285 677.20 375,450 3,861,184 667.00 243,133 427,544 677.40 376,894 3,936,419 667.20 256,815 477,539 677.60 378,339 4,011,942 667.40 270,496 530,270 677.80 379,783 4,087,754 667.60 284,177 585,737 678.00 381,228 4,163,855 667.80 297,859 643,941 678.20 382,672 4,240,245 668.00 311,540 704,881 678.40 384,117 4,316,924 668.20 312,882 767,323 678.60 385,561 4,393,892 668.40 314,224 830,033 678.80 387,006 4,471,149 668.60 315,565 893,012 679.00 388,450 4,548,694 668.80 316,907 956,259 679.20 389,895 4,626,529 669.00 318,249 1,019,775 679.40 391,339 4,704,652 669.20 319,591 1,083,559 679.60 392,784 4,783,065 669.40 320,933 1,147,611 679.80 394,228 4,861,766 669.60 322,274 1,211,932 680.00 395,673 4,940,756 669.80 323,616 1,276,521 680.20 397,166 5,020,040 670.00 324,958 1,341,379 680.40 398,659 5,099,622 670.20 326,342 1,406,509 680.60 400,152 5,179,503 670.40 327,726 1,471,915 680.80 401,644 5,259,683 670.60 329,110 1,537,599 681.00 403,137 5,340,161 670.80 330,494 1,603,559 681.20 404,630 5,420,938 671.00 331,878 1,669,797 681.40 406,123 5,502,013 671.20 333,262 1,736,311 681.60 407,616 5,583,387 671.40 334,647 1,803,102 681.80 409,109 5,665,060 671.60 336,031 1,870,169 682.00 410,602 5,747,031 671.80 337,415 1,937,514 682.20 412,095 5,829,300 672.00 338,799 2,005,135 682.40 413,587 5,911,868 672.20 340,183 2,073,033 682.60 415,080 5,994,735 672.40 341,567 2,141,208 682.80 416,573 6,077,901 672.60 342,951 2,209,660 683.00 418,066 6,161,365 672.80 344,335 2,278,389 673.00 345,719 2,347,394 673.20 347,103 2,416,677 673.40 348,487 2,486,236 673.60 349,871 2,556,071 673.80 351,256 2,626,184 674.00 352,640 2,696,574 674.20 354,024 2,767,240 ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 80 [79] Warning: Inflow Area = Inflow = Outflow = Primary = Summary for Pond Pond C2: Pond C2 Submerged Pond Pond C1 Primary device # 1 OUTLET by 1.10' 533.800 ac, 0.00% Impervious, Inflow Depth > 3.97" for NRCC-10yr-24hr event 443.22 cfs @ 13.05 hrs, Volume= 176.812 af 387.58 cfs @ 14.17 hrs, Volume= 153.916 af, Atten= 13%, Lag= 67.5 min 387.58 cfs @ 14.17 hrs, Volume= 153.916 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 650.00' Surf.Area= 386,547 sf Storage= 1,749,912 cf Peak Elev= 655.10' @ 14.17 hrs Surf.Area= 430,024 sf Storage= 3,841,601 cf (2,091,689 cf above start) Plug -Flow detention time= 336.5 min calculated for 113.743 af (64% of inflow) Center -of -Mass det. time= 132.0 min (1,053.1 - 921.1 ) Volume Invert Avail.Storage Storage Description #1 Elevation (feet) 644.00 646.00 648.00 650.00 652.00 654.00 656.00 657.50 644.00' 4,893,576 cf Custom Stage Data (Prismatic)Listed below (Recalc) Surf.Area (sq-ft) 223,281 260,873 309,169 386,547 406,548 421,590 436,857 448,455 Device Routing Invert Inc.Store (cubic -feet) 0 484,154 570,042 695,716 793,095 828,138 858,447 663,984 Outlet Devices Cum.Store (cubic -feet) 0 484,154 1,054,196 1,749,912 2,543,007 3,371,145 4,229,592 4,893,576 #1 Primary 644.00' #2 Device 1 #3 Device 1 650.00' 653.00' 72.0" Round Culvert L= 424.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 644.00' / 626.00' S= 0.0425'/' Cc= 0.900 n= 0.013, Flow Area= 28.27 sf 10.0" Vert. Orifice/Grate C= 0.600 40.0' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=387.57 cfs @ 14.17 hrs HW=655.10' (Free Discharge) 4-1=Culvert (Inlet Controls 387.57 cfs @ 13.71 fps) AL2=Orifice/Grate (Passes < 5.69 cfs potential flow) 3=Sharp-Crested Rectangular Weir(Passes < 399.36 cfs potential flow) ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC 0 LL Elevation (feet) Pond Pond C2: Pond C2 Hyd rog raph NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 81 4801 460 440 420 400--' 380 360 340 320- 300--' 280 260 240 220- 200- 180 160 140J 120' 100- 80" 60- 40= 20- +--+-----1--+--+ + --+--1--+--+--+--1--+--+--+--1--+--+--I +--+--r- j443.22cfs +1387.58cfs 1 1 + r 1 + + r 1 + + r 1 + + inflow Ares=533.8O0 ac 4 4 1 + + Qa+y�( Q+`, 1+y�F,�+ + r H + Rea* elev_6 i r � ba ge=3-cf-- ▪ 1-1 1 +1 I+ I+ ▪ 1-1 1 +1 I+ I~ + 1 + 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Pond Pond C2: Pond C2 Stage -Discharge 6571' 656� 655� 6541- 653 652: 651 650 649 648 647 646 645 644 Sharp -Crested Rectangular Weir i 1 + - r 7 11 11 11 11 0 50 100 150 200 250 Discharge (cfs) 300 350 400 U Inflow • Primary • Primary` ProposedConditions 11.10.21 Prepared by HDR, Inc HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Elevation (feet) 657J 656J 655+:- 6547:' 6537- 652J 651�� 650= 649J 648- 647- 646: 645: 644 50,000 Pond Pond C2: Pond C2 Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 100,000 150,000 200,000 250,000 300,000 Custom Stage Data i i NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Printed 11/15/2021 Page 82 350,000 400,000 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000 3,500,000 4,000,000 4,500,000 Storage (cubic -feet) ■ Surface` • Storage ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 83 Stage -Discharge for Pond Pond C2: Pond C2 Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) 644.00 0.00 651.80 3.09 644.15 0.00 651.95 3.25 644.30 0.00 652.10 3.41 644.45 0.00 652.25 3.56 644.60 0.00 652.40 3.70 644.75 0.00 652.55 3.84 644.90 0.00 652.70 3.97 645.05 0.00 652.85 4.10 645.20 0.00 653.00 4.22 645.35 0.00 653.15 11.94 645.50 0.00 653.30 25.95 645.65 0.00 653.45 44.06 645.80 0.00 653.60 65.48 645.95 0.00 653.75 89.75 646.10 0.00 653.90 116.58 646.25 0.00 654.05 145.74 646.40 0.00 654.20 177.05 646.55 0.00 654.35 210.38 646.70 0.00 654.50 245.60 646.85 0.00 654.65 282.63 647.00 0.00 654.80 321.37 647.15 0.00 654.95 361.76 647.30 0.00 655.10 387.46 647.45 0.00 655.25 391.03 647.60 0.00 655.40 394.57 647.75 0.00 655.55 398.08 647.90 0.00 655.70 401.56 648.05 0.00 655.85 405.00 648.20 0.00 656.00 408.42 648.35 0.00 656.15 411.81 648.50 0.00 656.30 415.17 648.65 0.00 656.45 418.51 648.80 0.00 656.60 421.82 648.95 0.00 656.75 425.10 649.10 0.00 656.90 428.36 649.25 0.00 657.05 431.59 649.40 0.00 657.20 434.80 649.55 0.00 657.35 437.98 649.70 0.00 657.50 441.14 649.85 0.00 650.00 0.00 650.15 0.09 650.30 0.33 650.45 0.69 650.60 1.11 650.75 1.52 650.90 1.83 651.05 2.09 651.20 2.32 651.35 2.54 651.50 2.73 651.65 2.92 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 84 Stage -Area -Storage for Pond Pond C2: Pond C2 Elevation Surface Storage (feet) (sq-ft) (cubic -feet) Elevation Surface Storage (feet) (sq-ft) (cubic -feet) 644.00 223,281 0 651.80 404,548 2,461,897 644.15 226,100 33,704 651.95 406,048 2,522,692 644.30 228,920 67,830 652.10 407,300 2,583,699 644.45 231,739 102,380 652.25 408,428 2,644,879 644.60 234,559 137,352 652.40 409,556 2,706,228 644.75 237,378 172,747 652.55 410,685 2,767,746 644.90 240,197 208,565 652.70 411,813 2,829,433 645.05 243,017 244,806 652.85 412,941 2,891,290 645.20 245,836 281,470 653.00 414,069 2,953,316 645.35 248,656 318,557 653.15 415,197 3,015,510 645.50 251,475 356,067 653.30 416,325 3,077,875 645.65 254,294 394,000 653.45 417,453 3,140,408 645.80 257,114 432,355 653.60 418,582 3,203,111 645.95 259,933 471,134 653.75 419,710 3,265,983 646.10 263,288 510,362 653.90 420,838 3,329,024 646.25 266,910 550,127 654.05 421,972 3,392,234 646.40 270,532 590,435 654.20 423,117 3,455,616 646.55 274,154 631,287 654.35 424,262 3,519,169 646.70 277,777 672,681 654.50 425,407 3,582,894 646.85 281,399 714,620 654.65 426,552 3,646,791 647.00 285,021 757,101 654.80 427,697 3,710,860 647.15 288,643 800,126 654.95 428,842 3,775,100 647.30 292,265 843,694 655.10 429,987 3,839,512 647.45 295,888 887,805 655.25 431,132 3,904,096 647.60 299,510 932,460 655.40 432,277 3,968,852 647.75 303,132 977,658 655.55 433,422 4,033,779 647.90 306,754 1,023,400 655.70 434,567 4,098,878 648.05 311,103 1,069,703 655.85 435,712 4,164,149 648.20 316,907 1,116,804 656.00 436,857 4,229,592 648.35 322,710 1,164,775 656.15 438,017 4,295,208 648.50 328,514 1,213,617 656.30 439,177 4,360,997 648.65 334,317 1,263,329 656.45 440,336 4,426,961 648.80 340,120 1,313,912 656.60 441,496 4,493,098 648.95 345,924 1,365,365 656.75 442,656 4,559,409 649.10 351,727 1,417,689 656.90 443,816 4,625,895 649.25 357,530 1,470,883 657.05 444,976 4,692,554 649.40 363,334 1,524,948 657.20 446,135 4,759,387 649.55 369,137 1,579,883 657.35 447,295 4,826,395 649.70 374,940 1,635,689 657.50 448,455 4,893,576 649.85 380,744 1,692,365 650.00 386,547 1,749,912 650.15 388,047 1,808,007 650.30 389,547 1,866,326 650.45 391,047 1,924,871 650.60 392,547 1,983,640 650.75 394,047 2,042,635 650.90 395,547 2,101,855 651.05 397,048 2,161,299 651.20 398,548 2,220,969 651.35 400,048 2,280,863 651.50 401,548 2,340,983 651.65 403,048 2,401,328 ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 85 Summary for Link A-1: Outfall Al Inflow Area = 278.500 ac, 0.00% Impervious, Inflow Depth > 3.62" for NRCC-10yr-24hr event Inflow = 278.19 cfs @ 12.50 hrs, Volume= 84.099 af Primary = 278.19 cfs @ 12.50 hrs, Volume= 84.099 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 0 LL Link A-1: Outfall Al Hyd rog raph 300� 280J 2601: 240- 220� 200- 180� 160- 140� 120- 100� 80= 60- 40- 20#'- 0 2 4 6 8 10 278.19 cfs 4 + + + + I 1 L 1 L 1 1 12 14 16 18 20 22 24 2▪ 6 28 30 32 34 36 38 40 42 44 46 48 Time (hours) n low e4=P 500 ac • L r1 ? r • + • r L 1 L 1i r 1 1 L ▪ L L 1 L ▪ tl r 1 L r 1 L L L C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 86 Summary for Link A-2: Outfall A2 Inflow Area = 37.000 ac, 0.00% Impervious, Inflow Depth = 2.75" for NRCC-10yr-24hr event Inflow = 87.90 cfs @ 12.32 hrs, Volume= 8.466 af Primary = 87.90 cfs @ 12.32 hrs, Volume= 8.466 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Tr 95 90� 85 80�� III 70 65� 'I� 60 n 551, I o O 45 LL 40= 35 30 �I 25 20 15 10� , 5= - - - 4 - - 1 - -I- r r I I 87.90 cfs 1 4 - - 4 - - L 4 - - 4 - - 4 4 - - 4 - - 4 ✓ r r r Link A-2: Outfall A2 Hyd rog raph ✓ r I y r I I r r r T 1010 v Area= 7 OO"c - r r ▪ TL 4 T 4 7 7 r L L 4 4 4 4 L 4 4 4 4 4 - - 4 - - 4 ✓ r r r r L L L 4 4 4 z 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 87 Summary for Link B-1: Total DA B Inflow Area = 312.300 ac, 0.00% Impervious, Inflow Depth > 3.73" for NRCC-10yr-24hr event Inflow = 347.70 cfs @ 13.01 hrs, Volume= 96.945 af Primary = 347.70 cfs @ 13.01 hrs, Volume= 96.945 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Link B-1: Total DA B Hyd rog raph 380� 360J 340J 3207:- 300+:- 280� 260� 240J ▪ 220=' 3 200- 0 180 • 1607:" 140= 120J 100= 60=' 40= 20 OJ f rt rt L L 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hours) Inflow 4rea=312,3O0 T L 1 i T 4- 1 1 28 30 32 34 36 38 40 42 44 46 48 C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 88 Summary for Link B-2: Outfall B2 Inflow Area = 62.000 ac, 0.00% Impervious, Inflow Depth = 1.99" for NRCC-10yr-24hr event Inflow = 88.85 cfs @ 12.44 hrs, Volume= 10.263 af Primary = 88.85 cfs @ 12.44 hrs, Volume= 10.263 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs 95' 90 'l1 85 80 75� 70 65 _ 60-' U , 1 w 55� - 1 3 50� O 45-' I LL - 40 35- 25 20 11 10, 1 5 Link B-2: Outfall B2 Hyd rog raph L 1 188.85 c1fs L ) 88.85 cfs 1 L i . 4 4- L L L 1 1 L 1 1 1 L L 1 A + rnfJOw Ar1lea=Si2 OOO a 4- r 1 i r 1 ir 1 1 r 1 1 r ✓ r r 1 r r 4 r r 1 L L L L r 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) C Inflow ❑ Primary ProposedConditions 11.10.21 NRCC 24-hr B NRCC-10yr-24hr Rainfall=5.04" Prepared by HDR, Inc Printed 11/15/2021 HydroCAD® 10.00-25 s/n 07102 © 2019 HydroCAD Software Solutions LLC Page 89 Summary for Link C: Total DA C Inflow Area = 879.200 ac, 0.00% Impervious, Inflow Depth > 3.03" for NRCC-10yr-24hr event Inflow = 511.88 cfs @ 13.47 hrs, Volume= 221.924 af Primary = 511.88 cfs @ 13.47 hrs, Volume= 221.924 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Link C: Total DA C yd rog raph L L 550J 500—/ 450- 400—/ 350— N —� 300— 200- 150— 100- 50— #/ 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) L C Inflow ❑ Primary DEMLR USE ONLY Date Received Fee Paid Permit Number Applicable Rules: ❑ Coastal SW -1995 ❑ Coastal SW - 2008 ❑ Ph II - Post Construction (select all that apply) ❑ Non -Coastal SW- HQW/ORW Waters ❑ Universal Stormwater Management Plan ❑ Other WQ Mgmt Plan: State of North Carolina Department of Environment and Natural Resources Division of Energy, Mineral and Land Resources STORMWATER MANAGEMENT PERMIT APPLICATION FORM This form may be photocopied for use as an original I. GENERAL INFORMATION 1. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Greensboro -Randolph Megasite 2. Location of Project (street address): 5525 Browns Meadow Road City:Liberty County:Randolph Zip:27298 3. Directions to project (from nearest major intersection): Travel south on US 421 from Greensboro. The site generally lies to the north of the intersection of US 421 and Julian Airport Road and to the north of the intersection of US 421 and Starmount Road. The site is south of Old 421 Road. 4. Latitude:35° 53' 36.4158" N Longitude:-79° 37' 38.877" W of the main entrance to the project. II. PERMIT INFORMATION: 1. a. Specify whether project is (check one): ®New ❑Modification n Renewal w/ Modificationt Renewals with modifications also requires SWU-102 — Renewal Application Form b.If this application is being submitted as the result of a modification to an existing permit, list the existing permit number , its issue date (if known) , and the status of construction: ❑Not Started ❑Partially Completed* n Completed* *provide a designer's certification 2. Specify the type of project (check one): ▪ Low Density ®High Density ❑Drains to an Offsite Stormwater System ❑Other 3. If this application is being submitted as the result of a previously returned application or a letter from DEMLR requesting a state stormwater management permit application, list the stormwater project number, if assigned, and the previous name of the project, if different than currently proposed, 4. a. Additional Project Requirements (check applicable blanks; information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748): ❑ CAMA Major ®Sedimentation/Erosion Control: 1000 ac of Disturbed Area ❑ NPDES Industrial Stormwater ®404/401 Permit: Proposed Impacts b.If any of these permits have already been acquired please provide the Project Name, Project/Permit Number, issue date and the type of each permit: 5. Is the project located within 5 miles of a public airport? No ❑Yes Form SWU-101 Version Oct. 31, 2013 Page 1 of 6 If yes, see S.L. 2012-200, Part VI: http://portal.ncdenr.org/web/lr/rules-and-regulations III. CONTACT INFORMATION 1. a. Print Applicant / Signing Official's name and title (specifically the developer, property owner, lessee, designated government official, individual, etc. who owns the project): Applicant/Organization:Greensboro Randolph Megasite Foundation Signing Official & Title:Tim Melvin b. Contact information for person listed in item la above: Street Address:324 West Wendover Avenue # 207 City:Greensboro State:NC Zip:27408 Mailing Address (if applicable): City: State: Zip: Phone: (336 ) 691-9803 Fax: ( Email:iimmelvin@aol.com c. Please check the appropriate box. The applicant listed above is: The property owner (Skip to Contact Information, item 3a) n Lessee* (Attach a copy of the lease agreement and complete Contact Information, item 2a and 2b below) n Purchaser* (Attach a copy of the pending sales agreement and complete Contact Information, item 2a and 2b below) n Developer* (Complete Contact Information, item 2a and 2b below.) 2. a. Print Property Owner's name and title below, if you are the lessee, purchaser or developer. (This is the person who owns the property that the project is located on): Property Owner/Organization:NCRR and Randolph County are co -owners Signing Official & Title:Anna Lea Moore(NCRR) and Hal Johnson (Randolph County) b. Contact information for person listed in item 2a above: Street Address:NCRR - 2809 Highwoods Blvd City:Raleigh State:NC Mailing Address (if applicable):Randolph County - 725 McDowell Road City:Asheboro Phone: (336 ) 318.6300 Email: Zip:27604 State:NC Zip:27205 Fax: ( 3. a. (Optional) Print the name and title of another contact such as the project's construction supervisor or other person who can answer questions about the project: Other Contact Person/Organization:Vickie Miller or Ken Trefzger/ HDR Signing Official & Title:Authorized Agent for Owners b. Contact information for person listed in item 3a above: Mailing Address:555 Fayetteville Street Suite 900 City:Ralegih State:NC Zip:27601 Phone: (919 ) 232-6600 Fax: ( Email:vickie.miller@hdrinc.com 4. Local jurisdiction for building permits: Randolph County Point of Contact:David Bryant Phone #: (336 ) 318-6565 Form SWU-101 Version Oct. 31, 2013 Page 2 of 7 IV. PROJECT INFORMATION 1. In the space provided below, briefly summarize how the stormwater runoff will be treated. All of the built upon area will drain into a combination of swales and storm drainage system that will outlet either to a wet pond located off the site pad or dry basins located on the pad and then to the wet ponds. Dry basins will reduce the peak discharges and the wet ponds will provide water quality. When BUA drains directly to a wet pond, the wet pond will reduce peak discharges and provide water quality. pond sized to meet the NCDEQ Stormater Desing Manual minimum design criteria. 2. a. If claiming vested rights, identify the supporting documents provided and the date they were approved: ❑ Approval of a Site Specific Development Plan or PUD Approval Date: ❑ Valid Building Permit Issued Date: ❑ Other: Date: b.If claiming vested rights, identify the regulation(s) the project has been designed in accordance with: ❑ Coastal SW - 1995 ❑ Ph II - Post Construction 3. Stormwater runoff from this project drains to the Cape Fear River basin. 4. Total Property Area: 1800 acres 5. Total Coastal Wetlands Area: acres 6. Total Surface Water Area: acres 7. Total Property Area (4) - Total Coastal Wetlands Area (5) - Total Surface Water Area (6) = Total Project Area+: acres + Total project area shall be calculated to exclude the following: the normal pool of impounded structures, the area between the banks of streams and rivers, the area below the Normal High Water (NHVV) line or Mean High Water (MHVV) line, and coastal wetlands landward from the NHW (or MHV line. The resultant project area is used to calculate overall percent built upon area (BUA). Non -coastal wetlands landward of the NHW (or MHVV) line may be included in the total project area. 8. Project percent of impervious area: (Total Impervious Area / Total Project Area) X 100 = % 9. How many drainage areas does the project have?3 (For high density, count 1 for each proposed engineered stormwater BMP. For low density and other projects, use 1 for the whole property area) 10. Complete the following information for each drainage area identified in Project Information item 9. If there are more than four drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. Form SWU-101 Version Oct. 31, 2013 Page 3 of 7 Basin Information Drainage Area Al Drainage Area A2 Drainage Area A3 Drainage Area B1 Receiving Stream Name Dodson Lake Dodson Lake Dodson Lake Dodson Lake Stream Class * WS-III WS-III WS-III WS-III Stream Index Number * 17-16-2 17-16-2 17-16-2 17-16-2 Total Drainage Area (sf) 4325860 5458798 12130840 12144188 On -site Drainage Area (sf) 4325860 5458798 12130840 12144188 Off -site Drainage Area (sf) 0 0 0 0 Proposed Impervious Area** (sf) 1928449 2889448 4817897 7748945 % Impervious Area** (total) 45 52.9 39.7 63.8 Impervious** Surface Area Drainage Area _ Drainage Area _ Drainage Area _ Drainage Area _ On -site Buildings/Lots (sf) On -site Streets (sf) On -site Parking (sf) On -site Sidewalks (sf) Other on -site (sf) Future (sf) Off -site (sf) Existing BUA*** (sf) Total (sf): * Stream Class and Index Number can be determined at: http://portal.ncdenr.org/web/wq/ps/csu/classifications ** Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. ***Report only that amount of existing BUA that will remain after development. Do not report any existing BUA that is to be removed and which will be replaced by new BUA. 11. How was the off -site impervious area listed above determined? Provide documentation. NA Protects in Union County: Contact DEMLR Central Office staff to check if the project is located within a Threatened & Endangered Species watershed that may be subject to more stringent stormwater requirements as per 15A NCAC 02B .0600. V. SUPPLEMENT AND O&M FORMS The applicable state stormwater management permit supplement and operation and maintenance (O&M) forms must be submitted for each BMP specified for this project. The latest versions of the forms can be downloaded from http: / / portal.ncdenr.org/web/wq/ws/ su/bmp-manual. VI. SUBMITTAL REQUIREMENTS Only complete application packages will be accepted and reviewed by the Division of Energy, Mineral and Land Resources (DEMLR). A complete package includes all of the items listed below. A detailed application instruction sheet and BMP checklists are available from http://portal.ncdenr.org/web/wq/ws/su/statesw/forms_docs. The complete application package should be submitted to the appropriate DEMLR Office. (The appropriate office may be found by locating project on the interactive online map at http://portal.ncdenr.org/web/wq/ws/su/maps.) Please indicate that the following required information have been provided by initialing in the space provided for each item. All original documents MUST be signed and initialed in blue ink. Download the latest versions for each submitted application package from http://portal.ncdenr.org/web/wq/ws/su/statesw/forms_docs. Initials 1. Original and one copy of the Stormwater Management Permit Application Form. 2. Original and one copy of the signed and notarized Deed Restrictions & Protective Covenants Form. (if required as per Part VII below) 3. Original of the applicable Supplement Form(s) (sealed, signed and dated) and O&M agreement(s) for each BMP. 4. Permit application processing fee of $505 payable to NCDENR. (For an Express review, refer to http://www.envhelp.org/pages/onestopexpress.html for information on the Express program Form SWU-101 Version Oct. 31, 2013 Page 4 of 7 and the associated fees. Contact the appropriate regional office Express Permit Coordinator for additional information and to schedule the required application meeting.) 5. A detailed narrative (one to two pages) describing the stormwater treatment/management for 6. A USGS map identifying the site location. If the receiving stream is reported as class SA or the receiving stream drains to class SA waters within 1/2 mile of the site boundary, include the 1/2 mile radius on the map. 7. Sealed, signed and dated calculations (one copy). 8. Two sets of plans folded to 8.5" x 14" (sealed, signed, & dated), including: a. Development/Project name. b. Engineer and firm. c. Location map with named streets and NCSR numbers. d. Legend. e. North arrow. f. Scale. g. Revision number and dates. h. Identify all surface waters on the plans by delineating the normal pool elevation of impounded structures, the banks of streams and rivers, the MHW or NHW line of tidal waters, and any coastal wetlands landward of the MHW or NHW lines. • Delineate the vegetated buffer landward from the normal pool elevation of impounded structures, the banks of streams or rivers, and the MHW (or NI-iW) of tidal waters. i. Dimensioned property/project boundary with bearings & distances. j. Site Layout with all BUA identified and dimensioned. k. Existing contours, proposed contours, spot elevations, finished floor elevations. 1. Details of roads, drainage features, collection systems, and stormwater control measures. m. Wetlands delineated, or a note on the plans that none exist. (Must be delineated by a qualified person. Provide documentation of qualifications and identify the person who made the determination on the plans. n. Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations. o. Drainage areas delineated (included in the main set of plans, not as a separate document). p. Vegetated buffers (where required). 9. Copy of any applicable soils report with the associated SHWT elevations (Please identify elevations in addition to depths) as well as a map of the boring locations with the existing elevations and boring logs. Include an 8.5"x11" copy of the NRCS County Soils map with the project area clearly delineated. For projects with infiltration BMPs, the report should also include the soil type, expected infiltration rate, and the method of determining the infiltration rate. (Infiltration Devices submitted to WiRO: Schedule a site visit for DEMLR to verify the SHWT prior to submittal, (910) 796-7378.) 10. A copy of the most current property deed. Deed book: Page No: 11. For corporations and limited liability corporations (LLC): Provide documentation from the NC Secretary of State or other official documentation, which supports the titles and positions held by the persons listed in Contact Information, item la, 2a, and/or 3a per 15A NCAC 2H.1003(e). The corporation or LLC must be listed as an active corporation in good standing with the NC Secretary of State, otherwise the application will be returned. http: / /www.secretary.state.nc.us/Corporations/CSearch.aspx VII. DEED RESTRICTIONS AND PROTECTIVE COVENANTS For all subdivisions, outparcels, and future development, the appropriate property restrictions and protective covenants are required to be recorded prior to the sale of any lot. If lot sizes vary significantly or the proposed BUA allocations vary, a table listing each lot number, lot size, and the allowable built -upon area must be provided as an attachment to the completed and notarized deed restriction form. The appropriate deed restrictions and protective covenants forms can be downloaded from http://portal.ncdenr.org/web/lr/state- stormwater-forms docs. Download the latest versions for each submittal. In the instances where the applicant is different than the property owner, it is the responsibility of the property owner to sign the deed restrictions and protective covenants form while the applicant is responsible for ensuring that the deed restrictions are recorded. By the notarized signature(s) below, the permit holder(s) certify that the recorded property restrictions and protective covenants for this project, if required, shall include all the items required in the permit and listed on the forms available on the website, that the covenants will be binding on all parties and persons claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted without concurrence from the NC DEMLR, and that they will be recorded prior to the sale of any lot. Form SWU-101 Version Oct. 31, 2013 Page 5 of 7 VIII. CONSULTANT INFORMATION AND AUTHORIZATION Applicant: Complete this section if you wish to designate authority to another individual and/or firm (such as a consulting engineer and/or firm) so that they may provide information on your behalf for this project (such as addressing requests for additional information). Consulting Engineer:Kenneth Trefzger Consulting Firm: HDR Engineering Inc. of the Carolinas Mailing Address:555 Fayetteville Street, Suite 900 City:Raleigh Phone: (919 ) 232-6651 Email:kenneth.trefzer@hdrinc.com State:NC Zip:27601 Fax: (919 ) 232-6654 IX. PROPERTY OWNER AUTHORIZATION (if Contact Information, item 2 has been filled out, complete this section) I, (print or type name of person listed in Contact Information, item 2a) , certify that I own the property identified in this permit application, and thus give permission to (print or type name of person listed in Contact Information, item la) with (print or type name of organization listed in Contact Information, item la) to develop the project as currently proposed. A copy of the lease agreement or pending property sales contract has been provided with the submittal, which indicates the party responsible for the operation and maintenance of the stormwater system. As the legal property owner I acknowledge, understand, and agree by my signature below, that if my designated agent (entity listed in Contact Information, item 1) dissolves their company and/or cancels or defaults on their lease agreement, or pending sale, responsibility for compliance with the DEMLR Stormwater permit reverts back to me, the property owner. As the property owner, it is my responsibility to notify DEMLR immediately and submit a completed Name/Ownership Change Form within 30 days; otherwise I will be operating a stormwater treatment facility without a valid permit. I understand that the operation of a stormwater treatment facility without a valid permit is a violation of NC General Statue 143-215.1 and may result in appropriate enforcement action including the assessment of civil penalties of up to $25,000 per day, pursuant to NCGS 143-215.6. Signature: Date: I, , a Notary Public for the State of , County of , do hereby certify that personally appeared before me this _ day of , and acknowledge the due execution of the application for a stormwater permit. Witness my hand and official seal, SEAL My commission expires Form SWU-101 Version Oct. 31, 2013 Page 6 of 7 X. APPLICANT'S CERTIFICATION I, (print or type name of person listed in Contact Information, item la) certify that the information included on this permit application form is, to the best of my knowledge, correct and that the project will be constructed in conformance with the approved plans, that the required deed restrictions and protective covenants will be recorded, and that the proposed project complies with the requirements of the applicable stormwater rules under 15A NCAC 2H .1000 and any other applicable state stormwater requirements. Signature: Date: I, , a Notary Public for the State of , County of do hereby certify that personally appeared before me this _ day of , and acknowledge the due execution of the application for a stormwater permit. Witness my hand and official seal, SEAL My commission expires Form SWU-101 Version Oct. 31, 2013 Page 7 of 7 WET POND 1 Drainage area number Minimum required treatment volume (cu ft) GENERAL MDC FROM 02H .1050 2 A3 B2 C2 402095 cf I 636375 cf I 115 640 cf I 3 Is the SCM sized to treat the SW from all surfaces at build -out? Yes Yes Yes 4 Is the SCM located away from contaminated soils? Yes Yes Yes 5 What are the side slopes of the SCM (H:V)? 3:1 3:1 3:1 6 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No No No 7 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes Yes Yes 8 Is there an overflow or bypass for inflow volume in excess of the design volume? No No No 9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Drawdown Orifice Drawdown Orifice 10 If applicable, will the SCM be cleaned out after construction? 11 Does the maintenance access comply with General MDC (8)? 12 Does the drainage easement comply with General MDC (9)? 13 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)? 14 Is there an O&M Agreement that complies with General MDC (11)? 15 Is there an O&M Plan that complies with General MDC (12)? 16 Does the SCM follow the device specific MDC? Yes Yes Yes 17 Was the SCM designed by an NC licensed professional? Yes Yes Yes WET POND MDC FROM 02H .1053 18 Sizing method used SA/DA SA/DA SA/DA 19 Has a stage/storage table been provided in the calculations? Yes Yes Yes 20 Elevation of the excavated main pool depth (bottom of sediment removal) (fmsl) 671.00 607.00 643.00 21 Elevation of the main pool bottom (top of sediment removal) (fmsl) 672.00 608.00 644.00 22 Elevation of the bottom of the vegetated shelf (fmsl) 677.50 613.50 649.50 23 Elevation of the permanent pool (fmsl) 678.00 614.00 650.00 24 Elevation of the top of the vegetated shelf (fmsl) 378.50 614.50 650.50 25 Elevation of the temporary pool (fmsl) 26 Surface area of the main permanent pool (square feet) 168544 214613 386547 27 Volume of the main permanent pool (cubic feet) 783488 cf 1113926 cf 1763487 cf 28 Average depth of the main pool (feet) 4.80 ft 5.30 ft 4.60 ft 29 Average depth equation used Equation 3 Equation 3 Equation 3 30 If using equation 3, main pool perimeter (feet) 1394.0 ft 1874.0 ft 2417.0 ft 31 If using equation 3, width of submerged veg. shelf (feet) 3.0 ft 3.0 ft 3.0 ft 32 Volume of the forebay (cubic feet) 107084 cf 183485 cf 286058 cf 33 Is this 15-20% of the volume in the main pool? Yes Yes Yes 34 Clean -out depth for forebay (inches) 36 in 48 in 72 in 35 Design volume of SCM (cu ft) 36 Is the outlet an orifice or a weir? Orifice Orifice Orifice 37 If orifice, orifice diameter (inches) 6 in 7 in 10 in 38 If weir, weir height (inches) 39 If weir, weir length (inches) 40 Drawdown time for the temporary pool (days) 4 4.6 4.2 41 Are the inlet(s) and outlet located in a manner that avoids short- circuiting? Yes Yes Yes 42 Are berms or baffles provided to improve the flow path? No No No 43 Depth of forebay at entrance (inches) 48 in 66 in 66 in 44 Depth of forebay at exit (inches) 6 in 6 in 6 in 45 Does water flow out of the forebay in a non -erosive manner? Yes Yes Yes 46 Width of the vegetated shelf (feet) 6 ft 6 ft 6 ft 47 Slope of vegetated shelf (H:V) 6:1 6:1 6:1 48 Does the orifice drawdown from below the top surface of the permanent pool? Yes Yes Yes 49 Does the pond minimize impacts to the receiving channel from the 1- yr, 24-hr storm? Yes Yes Yes 50 Are fountains proposed? (If Y, please provide documentation that MDC(9) is met.) No No No 51 Is a trash rack or other device provided to protect the outlet system? Yes Yes Yes 52 Are the dam and embankment planted in non -clumping turf grass? 53 Species of turf that will be used on the dam and embankment 54 Has a planting plan been provided for the vegetated shelf? ADDITIONAL INFORMATION 55 Please use this space to provide any additional information about the wet pond(s): Wet Pond 4 8:09 PM 1/31/2022 DRY POND 1 2 Drainage area number Minimum re.uired treatment volume cu ft GENERAL MDC FROM 02H .1050 Al I A2 B1 Cl 3 Is the SCM sized to treat the SW from all surfaces at build -out? Yes Yes Yes Yes 4 Is the SCM located away from contaminated soils? No No No No 5 What are the side slopes of the SCM (H:V)? 3:1 3:1 3:1 3:1 6 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No No No No 7 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? 8 Is there an overflow or bypass for inflow volume in excess of the design volume? No No No No 9 What is the method for dewatering the SCM for maintenance? 10 If applicable, will the SCM be cleaned out after construction? Yes Yes Yes Yes 11 Does the maintenance access comply with General MDC (8)? 12 Does the drainage easement comply with General MDC (9)? 13 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)? 14 Is there an O&M Agreement that complies with General MDC (11)? 15 Is there an O&M Plan that complies with General MDC (12)? 16 Does the SCM follow the device specific MDC? 17 Was the SCM designed by an NC licensed professional? Yes Yes Yes Yes DRY POND MDC FROM 02H .1062 , 18 SHWT elevation (fmsl) 19 Elevation of the bottom of the dry pond (fmsl) 684 654 654 661 20 Distance from bottom to SHWT (feet) 21 Elevation of the temporary pool during the design storm (feet) 22 Ponding depth of the design storm (feet) 23 Will the dry pond be uniformly graded to flow toward the outlet? Yes Yes Yes Yes 24 Is a low flow channel being provided? Yes Yes Yes Yes 25 Are the inlet(s) and outlet located in a manner that avoids short- circuiting? 26 Will berms or baffles be provided to increase the flow path? No No No No 27 What method of pretreatment will be provided? 28 Design volume of SCM (cu ft) 29 Diameter of drawdown orifice (in) 30 Drawdown time for the temporary pool (hours) 31 Does the pond minimize impacts to the receiving channel from the 1- yr, 24-hr storm? Yes Yes Yes Yes 32 Is there a small permanent pool near the orifice to prevent clogging? No No No No 33 Will the outlet be designed to prevent clogging? 34 Are the dam and embankment planted in non -clumping turf grass? 35 Species of turf that will be used on the dam and embankment 36 Will trees and shrubs be prevented from growing on the dam and embankment? ADDITIONAL INFORMATION Please use this space to provide any additional information about the dry pond(s): 37 The dry ponds are only being used to provide peak attenuation and not designed to provide water quality. J Dry Pond 5 8:09 PM 1/31/2022