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File Documents.334 McSkimming Rd.0073-2020-BRES (29)
DRAINAGE REPORT FOR LOT 11 ASPEN GROVE SUBDIVISION CITY OF ASPEN, COLORADO PARCEL ID: 2373718103002 PREPARED FOR: Dick Hampleman PREPARED BY: High Country Engineering, Inc. 1517 Blake Avenue, Suite 101 Glenwood Springs, CO 81601 (970) 945-8676 April 3, 2020 Revised: January 8, 2021 HCE JOB NUMBER: 2181046.00 04/08/2021 Reviewed by Engineering 09/24/2021 12:01:47 PM "It should be known that this review shall not relieve the applicant of their responsibility to comply with the requirements of the City of Aspen. The review and approval by the City is offered only to assist the applicant's understanding of the applicable Engineering requirements." The issuance of a permit based on construction documents and other data shall not prevent the City of Aspen from requiring the correction of errors in the construction documents and other data. Page 2 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc TABLE OF CONTENTS SECTION PAGE I. GENERAL LOCATION AND DESCRIPTION ................................................................ 4 II. DRAINAGE STUDIES ...................................................................................................... 4 III. DRAINAGE DESIGN CRITERIA ..................................................................................... 5 IV. DRAINAGE FACILITY DESIGN ..................................................................................... 7 V. CONCLUSION ................................................................................................................. 12 VI. REFERENCES ................................................................................................................. 13 EXHIBITS: 1. Vicinity Map (8.5”x11”) 2. SCS Soils Map (8.5”x11”) 3. FEMA Map (11”x17”) 4. Historic Drainage Conditions (24”x36”) 5. Proposed Drainage Conditions (24”x36”) 6. Detail Sheet (24”x36”) 7. Soils Report APPENDICES: Hydrologic Computations Historic Conditions Proposed Conditions Detention Calculations Hydraulic Computations Storm Sewer Calculations Swale Calculations Trench Drain Calculations Bioretention Pond Calculations Aspen Charts and Figures 04/08/2021 04/08/2021 Page 4 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc I. GENERAL LOCATION AND DESCRIPTION A. Location The subject property is located at Lot 11 in the Aspen Grove Subdivision within the City of Aspen, County of Pitkin, State of Colorado. The site is located at the physical address of 334 McSkimming Road. A Vicinity Map has been included as Exhibit 1. B. Description of Existing Property The existing lot is approximately 15,913 square feet (0.365 acres). The lot is currently developed with a single-family residence. Ground cover consists mainly of a gravel driveway, Aspen trees and grassed ground cover. The site is bordered by private property to the west, north and south, and McSkimming Road right-of-way to the east. Generally site drainage flows from east to west across the property. Existing site drainage discharges offsite via sheet flow along the western property line on the adjacent western private property. Two offsite basins drain onto the property from the east and southeast. Grades on the property range from 4-percent to 11-percent, approximately. C. Proposed Improvements Proposed improvements consist of construction of an approximately 2,497 square foot single- family residence with concrete driveway, landscaping and stormwater conveyance and management facilities. D. Soils Description The City of Aspen soils map locates this site in the Type “B” soils area. Per the NRCS Web Soil Survey, this site primarily lies within mapping unit type 76 – Mine loam, 12 to 25 percent slopes. The Soil Conservation Service describes the soil as well-drained with low runoff, moderately high to high permeability, and low water storage capacity. The soils are classified as hydrologic soil group ‘A’. Additional soils information can be referenced in Exhibit 2. A site specific geotechnical investigation has been performed by CTL Thompson (Project No. GS06310.000-125 dated January 3, 2019). At the location of exploratory boring, subsurface conditions consist of approximately 12 feet of clayey to silty sand fill with gravel underlain by natural clayey to silty sand. Groundwater was not observed at the time of exploratory boring. A copy of the geotechnical investigation can be referenced in Exhibit 7. II. DRAINAGE STUDIES A. Major Drainage Way Planning and Influential Parameters The site is located within FEMA’s major drainage study of the area on its Flood Insurance Rate Map (FIRM) No. 08097C0366E which has an effective date of August 15, 2019. The area of interest within the site is located in Zone X. This zone is described as areas determined to be outside the 100-year and 500-year floodplains. Refer to Exhibit 3 for the FEMA map. 04/08/2021 Page 5 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc Mud flow was not analyzed for the site since the site is located outside of the Mud Flow Zone as indicated in the Storm Drainage Master Plan for the City of Aspen, Colorado by WRC Engineering, Inc. in November of 2001. B. Previous Drainage Studies Per the November 2001 study completed by WRC Engineering, Inc. titled, “Storm Drainage Master Plan for the City of Aspen, Colorado,” the site is located outside of the study area boundary as shown on figure ES-2 and is not impacted by the results and recommendations of that study. C. Receiving System and Effects of Adjacent Drainage Issues To our knowledge, there are no major drainage issues with the adjacent properties that affect the site or that the site affects. A majority of runoff from the existing site surface discharges near the northwest property corner. The existing flow leaves the property and overland flows to the west/ southwest between a series of sheet flow, non-prominent swales, and roadside ditches approximately until the CO HWY 82 intersection. Prior to reaching the HWY 82 intersection, drainage sheet flows across McSkimming Road and ultimately discharges to the Salvation Ditch. III. DRAINAGE DESIGN CRITERIA A. Criteria This drainage study was prepared in conformance with the City of Aspen, Colorado Urban Runoff Management Plan (URMP), dated April of 2010 and the revised sections dated thereafter. More than 1,000 square feet of area will be disturbed with the proposed construction; therefore, the site is viewed as a Major Project per the URMP. More than 1,000 square feet are being disturbed and more than 25-percent of the overall site is being disturbed, so water quality for the entire site will be necessary per the URMP. The existing site was analyzed in its historic condition (i.e. no improvements). The two offsite basins consisting of existing single-family residences, aspen groves, and grassed ground cover were analyzed as existing (open space and pervious area) per the URMP. The onsite water treatment systems were sized to pass the offsite flow. Water Quality Capture Volume (WQCV) will be determined for the site that will undergo site grading as per the URMP standards. The WQCV is defined as the treatment for up to the 80th percentile runoff event, corresponding to between a 6-month to 1-year event. The WQCV was determined using the equations and Figure 8.13 from Chapter 8 of the URMP. The WQCV equation is: Volume (ft3) =WQCV (watershed-inches) x 1/12(ft./in) x area(acres) x 43,560 ft2/acre. Runoff for the onsite basins will be routed through a series of storm sewer and swales receiving storm water from sheet flow and downspouts to either of two bioretention ponds where runoff will be treated for WQCV. B. Hydrologic Criteria The hydrologic methods for this study are outlined in the URMP from the City of Aspen, Colorado 04/08/2021 Page 6 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc (April, 2010) and the Microsoft Excel spreadsheet for the Rational Method. The rainfall amounts for each basin were obtained using Figure 2.1 “IDF Curves for Aspen, Colorado” in the URMP publication from the City of Aspen, Colorado. Using these curves, the rainfall intensity corresponding to the 2-yr, 1-hr storm 10-yr, 1-hr storm, and 100-yr, 1-hr storm event were determined based on the time of concentration for each basin. Figure 3.3 from the URMP was used to determine the runoff coefficients for the 2-year, 10-year and 100-year storm events since the soils were determined to be type ‘B’ soils. This site is located outside the Aspen Mountain Drainage Basin delineated in URMP Figure 1.1. Additionally, the added impervious area is more than 25% of the total site and disturbs or adds more than 1,000 square feet. Therefore detention to the historic peak flow rates for the 5- and 100-year events is required. The bioretention ponds were sized to handle the WQCV and detain the 5-year and 100-year runoff per the URMP. Type ‘B’ soils were used for the site per Figure 3.1 NRCS Soil Map for Aspen. All charts and figures mentioned from the URMP are located in the last section of the appendices under the “Aspen Charts/Figures” section. C. Hydraulic Criteria The swales and storm sewer within the system have been sized using the Hydraflow Express and Hydraflow Storm Sewer calculator within AutoDesk Civil 3D, and bioretention ponds have been sized with HydroCAD. All drainage features and structures have the capacity to carry entire basin design flows anticipated in a major storm event. See basin descriptions below for explanation. D. Site Constraints There are no utilities, streets or structures that cause major site constraints for the drainage system design. E. Easements and Irrigation Facilities There are no major drainage ways, drainage easements or tracts located on the site. There are also no irrigation facilities onsite that affect the overall proposed development. F. Low Impact Site Design Two bioretention ponds will be implemented to provide the required WQCV and detention volume per the URMP. Should the bioretention ponds capacity be exceeded, runoff will discharge offsite along historic flow paths. G. Principles 04/08/2021 Page 7 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc The 9 Principles for storm water quality management were followed during the design process to create the best storm water design and water quality management. The following is a summary of compliance with the Storm Drainage Principles outlined in the City of Aspen Urban Runoff Management Plan: 1. Consider storm water quality needs early in the design process Storm water quality needs were considered early in the design process, as recommended. 2. Use the entire site when planning for storm water quality treatment. With the use of a bioretention ponds and vegetated swales, the entire site is utilized for water quality treatment. 3. Avoid unnecessary impervious area Efforts were made to avoid unnecessary impervious areas in drainage design. Existing impervious areas will be redeveloped, but the site will have an overall increase in impervious area. 4. Reduce runoff rates and volumes to more closely match natural conditions Runoff rates and volumes have been reduced, as recommended, by implementing bioretention ponds served by vegetated swales and storm sewer. All impervious areas will drain the proposed bioretention ponds. 5. Integrate storm water quality management and flood control The proposed bioretention pond has been sized to provide both water quality and detention as required by the URMP. All conveyance facilities have been adequately sized to handle the required design storms. 6. Develop storm water quality facilities that enhance the site and environment. Vegetated swales enhance the landscaping aesthetic. The water quality facilities are bioretention ponds. 7. Use a treatment train approach Vegetated swales provide a level of treatment prior to the bioretention ponds. 8. Design sustainable facilities that can be safely maintained The proposed storm water quality facilities have been designed to be easily accessible and safely maintained, as recommended. 9. Design and maintain facilities with public safety in mind The proposed storm water quality facilities have been designed with public safety in mind, as required. IV. DRAINAGE FACILITY DESIGN A. General Concept 04/08/2021 Page 8 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc Currently the property is a developed parcel with an existing single-family residence. Proposed improvements consist of construction of an approximately 2,497 square foot single- family residence with concrete driveway, landscaping and stormwater conveyance and management facilities. Runoff from all impervious areas onsite will be directed to either of two proposed bioretention ponds for treatment and detention. Roof downspouts will surface discharge and sheet flow to either swales within yard areas, or collected by inlets within the driveway and piped to the bioretention ponds. Offsite drainage entering the site will be intercepted by swales and directed to the bioretention ponds. Runoff greater than the required detention volume will be allowed to discharge along historic drainage routes. All conveyance facilities have been sized to safely convey the 100-year storm event. B. Historic Drainage Basin Descriptions The existing drainage pattern onsite generally flows from east to west and surface discharges at the northwest corner of the property. As previously mentioned the site is currently undeveloped and has been analyzed in its historic conditions. The historic site has been analyzed as a single onsite basin, and two offsite basins; EX-1, EX-OS1 and EX-OS2 respectively. Basin EX-1 is comprised of the property boundary. Basin EX-OS1 is east of the property and drains onsite near the northeast property corner. Basin EX-OS2 is also east of the property and drains onsite near the southeast property corner. An existing conditions drainage map, EXDR can be referenced in Exhibit 4. The existing basins are more described as the following: EX-1 Basin EX-1 encompasses the entire property boundary. Ground cover consists of native grasses under wooded aspen trees. Runoff from this basin sheet flows generally from east to west and surface discharges near the northwest property corner. This discharge point is labeled as “1” on the existing drainage map. Basin EX-1 receives runoff from both offsite basins EX-OS1 and EX-OS2. EX-OS1 Basin EX-OS1 is east of the site and consists of multiple private residences. Ground cover consists of native grasses under wooded aspen trees, grassed lawn areas, single-family homes and paved driveways. Runoff from this basin flows from east to west and surface discharges to a point labeled “2” on the existing drainage basin map. While aerial topography shows this basin discharging at point 2, it should be noted that drainage is intercepted rerouted by an adjacent existing single-family residence uphill of the site. It is unknown how much drainage theoretically produced from this basin reaches the site. EX-OS2 Basin EX-OS2 is east of the site and consists of a private residence and cemetery. Ground cover consists of native grasses under wooded aspen trees, grassed lawn areas, single-family home and paved driveway. Runoff from this basin flows from east to west and surface discharges to a point labeled “3” on the existing drainage basin map. While aerial topography shows this basin discharging at point 2, it should be noted that drainage is intercepted rerouted by an adjacent existing single-family residence uphill of the site. It is unknown how much drainage theoretically produced 04/08/2021 Page 9 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc from this basin reaches the site. There are no negative impacts from the runoff to the adjacent properties as runoff has low discharge rates that sheet flow across permeable land. Runoff does not drain directly to downstream structures. Refer to Exhibit 4 for an existing drainage basin delineation and information. Table 1 below summarizes existing basin information. Table 1 – Historic Basin Information C. Proposed Basin Description The proposed site has been analyzed as three onsite basins, and two offsite basins; PR-1, PR-2, PR- 3, EX-OS1 and EX-OS2 respectively. Basins PR-1 through PR-3 comprise the property boundary and includes the proposed construction of a single-family residence, concrete driveway and landscaping. Basins EX-OS1 and EX-OS2 are as previously described above in Section IV(B). A proposed conditions drainage map, PRDR can be referenced in Exhibit 5. The proposed basins are more described as the following: PR-1 Basin PR-1 consists of the driveway and northern half of the roof. Proposed ground cover for this basin is anticipated to be concrete pavement, roof, and some grassed open space. Drainage from the proposed driveway will be collected within a drain pan along the north edge of the driveway and trench drain in front of the garage. From there it is piped along the north side of the residence to proposed bioretention pond BP-1 for treatment and runoff rate control and treatment. Roof drainage is to be collected via roof drain leader and connected to the storm sewer routed to bioretention pond BP-1. The pond discharge is proposed to be overland flow over a weir structure at discharge point 1. PR-2 Basin PR-2 consists of a majority of the property including the proposed single-family residence. Pervious ground cover for this basin is anticipated to be grassed lawns, landscaping. Impervious surfaces include the proposed residence, driveway and concrete front entrance walkway. Roof drainage from the northeast, southeast and southwest is proposed to surface discharge via downspout to a swale that will convey drainage to the proposed bioretention pond BP-2. All open space drainage will be directed to the proposed bioretention pond via swale. The pond discharge is proposed to be overland flow over a weir structure at discharge point 2. PR-3 Basin PR-3 consists of the northwest and southwest property corners. The southwest portion of this basin is undisturbed from existing conditions. The northwest portion of this basin is to be graded in BASIN AREA, ACRES C, 5YR I, 5YR Q5-YEAR, CFS C, 100YR I, 100 YR Q100-YEAR, CFS EX-1 0.365 0.08 2.47 0.07 0.35 4.76 0.61 EX-OS1 0.964 0.08 2.04 0.16 0.35 3.92 1.32 EX-OS2 0.784 0.08 1.75 0.11 0.35 3.37 0.92 ONSITE TOTAL 0.07 ONSITE TOTAL 0.61 04/08/2021 Page 10 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc the proposed conditions. Disturbed areas are proposed to be grass covered and will discharge under existing drainage patterns at discharge points 1 and 3. PR-OS1 Basin PR-OS1 is east of the site and consists of multiple private residences. Ground cover consists of native grasses under wooded aspen trees, grassed lawn areas, single-family homes and paved driveways. Runoff from this basin flows from east to west and surface discharges to a point labeled “3” on the proposed drainage basin map. While aerial topography shows this basin discharging at point 3, it should be noted that drainage is intercepted rerouted by an adjacent existing single-family residence uphill of the site. It is unknown how much drainage theoretically produced from this basin reaches the site. PR-OS2 Basin PX-OS2 is east of the site and consists of a private residence and cemetery. Ground cover consists of native grasses under wooded aspen trees, grassed lawn areas, single-family home and paved driveway. Runoff from this basin flows from east to west and surface discharges to a point labeled “4” on the proposed drainage basin map. While aerial topography shows this basin discharging at point 4, it should be noted that drainage is intercepted rerouted by an adjacent existing single-family residence uphill of the site. It is unknown how much drainage theoretically produced from this basin reaches the site. Table 2 below summarizes the proposed basin information. Refer to HydroCAD outputs in the appendices for total site discharge post-detention. Table 2 – Proposed Basin Information BASIN AREA, AC C, 5YR I, 5YR Q5, CFS Q5 DETAINED, CFS C, 100YR I, 100 YR Q100-YEAR, CFS Q100 DETAINED, CFS PR-1 0.051 0.52 3.29 0.09 0.00 0.64 6.33 0.21 0.11 PR-2 0.196 0.2 3.29 0.13 0.00 0.44 6.33 0.55 0.22 PR-3 0.118 0.08 3.08 0.03 0.03 0.35 5.93 0.24 0.24 PR-OS1 0.964 0.17 1.96 0.32 0.32 0.43 3.76 1.56 1.56 PR-OS2 0.784 0.14 1.8 0.2 0.2 0.41 3.46 1.11 1.11 ONSITE TOTAL 0.25 0.03 ONSITE TOTAL 1.00 0.50 D. Downstream Impacts The proposed onsite grading and bioretention ponds will not produce negative downstream impacts during frequent storm events by capturing and treating the onsite WQCV. This will result in less flow from the site during frequent storm events. There are no downstream facilities from the site to be negatively impacted by the site’s redevelopment. The onsite runoff will leave the site after cleansed in the water quality facilities thus preventing the spread of pollutants downstream. 04/08/2021 Page 11 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc The bioretention ponds were sized to handle the WQCV and detain the 5-year and 100-year runoff per the URMP. Table 3 below summarizes the WQCV calculations. Table 3. Proposed WQCV Table BASIN AREA (S.F.) IMPERVIOUS AREA (SF) PERCENT IMPERVIOUS (%) EFFECTIVE IMPERVIOUS (%) PR-1 2230 1633 73.2 73.2 PR-2 8552 1754 20.5 20.5 PR-3 5131 0 0.0 0.0 TOTAL 15913 3387 21.3 BASIN BIORETENTION AREA WQCV (Watershed inches) WQCV (CF) PR-1 BP-1 0.149 27.7 PR-2 BP-2 0.049 34.9 PR-3 N/A 0.0 0.0 TOTAL 0.198 62.6 Detention analysis for the 5-year and 100-year events was performed per URMP Chapter 5.6.1 - Rational Volume Method for Detention Volume. The historic runoff flowrates for the site are 0.07cfs and 0.61cfs for the 5-year and 100-year events respectively. Detention calculation analysis can be referenced in the appendices. Table 4 below summarizes the required and provided detention volumes. Table 4. Detention Volume Summary POND 5-YR DETENTION (CF) 100-YR DETENTION (CF) BP-1 106 129 BP-2 156 337 TOTAL 262 466 REQUIRED 85.6 163.5 EXCESS 176.4 302.5 The site was analyzed as a single basin for required detention volume due to the single historic basin EX-1. The proposed bioretention ponds combine to provide the required detention volume. Basins PR-1 and PR-2 contribute impervious area runoff that requires detention and treatment. Basin PR-3 is 100% pervious ground cover and allowed to release undetained even though the area is included in the detention analysis. The detention volume provided in the bioretention ponds accounts for the area in basin PR-3 that is allowed to release undetained. If the bioretention ponds surpass the WQCV and detention volume, the system will allow runoff to overflow the pond weirs and continue along historic drainage patterns. Calculations for the proposed drainage facilities are included in the appendices of this report under the Facility Calculations section. 04/08/2021 Page 12 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc F. Operation and Maintenance The proposed drainage facilities are to be constructed in conformance with the City of Aspen Urban Runoff Management Plan, dated April 2010 and revised thereafter. The bio-retention ponds will need to be inspected and maintained quarterly to verify clogging has not occurred and it is functioning properly. Debris and liter removal shall occur routinely. Clean outs can be used to inspect pipes by cameras to determine the location of clogging or collapsed pipe. If clogging or standing water is observed, thoroughly run a sewer snake through the pipe to unclog. Should clogging or standing water remain, the growing media mix layer shall be removed and new growing media mix added. Solid pipes may be jetted clear if clogged. The owner of the property will be responsible for the maintenance and upkeep of the drainage facilities. The property owner shall dispose of sediment and any other waste material removed from a reservoir at suitable disposal sites and in compliance with local, state, and federal waste regulations. This project includes “Low Impact Site Design” to mimic the natural pre-development hydraulic pattern. Storm water runoff is to be in contact with soils and plants prior to reaching the City of Aspen curb and gutter system. The plants and soil are to act as filters to remove pollutants. The proposed plants and soils are present along the lengths of proposed graded swales and within the proposed bioretention ponds. V. CONCLUSION A. Compliance with Standards This drainage report has been prepared in accordance with City of Aspen Regulations. The proposed bio retention ponds will capture and treat the proposed WQCV and provide the required detention volume for all impervious areas added to the site. B. Drainage Concept The proposed drainage design will be effective in controlling any adverse downstream impacts on landowners or structures. Water quality issues will be minimal as the runoff will be intercepted and routed to the proposed bio retention ponds. 04/08/2021 Page 13 J:\SDSKPROJ\218\1046\Drainage\2181046 - DRAINAGE STUDY LOT 11 ASPEN GROVE.doc VI. REFERENCES United States Department of Agriculture, Soil Conservation Service: Soil Survey of Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and GARFIELD Counties, May 1992. City of Aspen, Colorado: Design and Construction Standards, June 2005. City of Aspen, Colorado: Urban Runoff Management Plan. April 2010. WRC Engineering, Inc. Storm Drainage Master Plan for the City of Aspen, Colorado. November 2001. 04/08/2021 EXHIBIT 1 VICINITY MAP 04/08/2021 Pitkin Maps & More 4,800 800.0 Legend 1: WGS_1984_Web_Mercator_Auxiliary_Sphere Feet0800.0400.00 Notes THIS MAP IS FOR INFORMATIONAL PURPOSES. Pitkin County GIS makes no warranty or guarantee concerning the completeness, accuracy, or reliability of the content represented. Map Created on 11:11 AM 08/20/19 at http://www.pitkinmapsandmore.com State Highway Road Centerline 4K Primary Road Secondary Road Service Road Parcel Boundary Rivers and Creeks Continuous Intermittent River, Lake or Pond Town Boundary Federal Land Boundary BLM State of Colorado USFS 04/08/2021 EXHIBIT 2 SCS SOILS MAP 04/08/2021 Soil Map—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/7/2019 Page 1 of 3 43 3 8 9 4 6 43 3 8 9 5 4 43 3 8 9 6 2 43 3 8 9 7 0 43 3 8 9 7 8 43 3 8 9 8 6 43 3 8 9 9 4 43 3 9 0 0 2 43 3 8 9 3 8 43 3 8 9 4 6 43 3 8 9 5 4 43 3 8 9 6 2 43 3 8 9 7 0 43 3 8 9 7 8 43 3 8 9 8 6 43 3 8 9 9 4 43 3 9 0 0 2 344141 344149 344157 344165 344173 344181 344133 344141 344149 344157 344165 344173 344181 39° 11' 10'' N 10 6 ° 4 8 ' 1 6 ' ' W 39° 11' 10'' N 10 6 ° 4 8 ' 1 4 ' ' W 39° 11' 8'' N 10 6 ° 4 8 ' 1 6 ' ' W 39° 11' 8'' N 10 6 ° 4 8 ' 1 4 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 15 30 60 90 Feet 0 4 9 18 27 Meters Map Scale: 1:315 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. 04/08/2021 MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Survey Area Data: Version 9, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Data not available. The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/7/2019 Page 2 of 3 04/08/2021 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 76 Mine loam, 12 to 25 percent slopes 0.3 100.0% Totals for Area of Interest 0.3 100.0% Soil Map—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/7/2019 Page 3 of 304/08/2021 Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties 76—Mine loam, 12 to 25 percent slopes Map Unit Setting National map unit symbol: jq75 Elevation: 7,500 to 9,500 feet Mean annual precipitation: 18 to 20 inches Mean annual air temperature: 36 to 40 degrees F Frost-free period: 70 to 80 days Farmland classification: Not prime farmland Map Unit Composition Mine and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Mine Setting Landform: Fans, valley sides Down-slope shape: Linear Across-slope shape: Linear Parent material: Moderately coarse alluvium derived from metamorphic rock and/or moderately coarse colluvium derived from metamorphic rock Typical profile H1 - 0 to 4 inches: loam H2 - 4 to 16 inches: gravelly sandy loam H3 - 16 to 32 inches: cobbly sandy loam H4 - 32 to 37 inches: gravelly sandy loam H5 - 37 to 45 inches: very cobbly loamy sand H6 - 45 to 60 inches: very gravelly sandy loam Properties and qualities Slope: 12 to 25 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 6.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 4.8 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6e Map Unit Description: Mine loam, 12 to 25 percent slopes---Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/7/2019 Page 1 of 204/08/2021 Hydrologic Soil Group: A Other vegetative classification: Spruce-Fir (null_21) Hydric soil rating: No Minor Components Other soils Percent of map unit: 15 percent Hydric soil rating: No Data Source Information Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Survey Area Data: Version 9, Sep 10, 2018 Map Unit Description: Mine loam, 12 to 25 percent slopes---Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/7/2019 Page 2 of 204/08/2021 EXHIBIT 3 FEMA MAP 04/08/2021 BY NO . DA T E BY PROJECT NO. OR 5 3 4 - 0 6 7 0 0 I N M E T R O D E N V E R UN D E R G R O U N D M E M B E R U T I L I T I E S EX C A V A T E F O R T H E M A R K I N G O F BE F O R E Y O U D I G , G R A D E , O R CA L L 2 - B U S I N E S S D A Y S I N A D V A N C E 1- 8 0 0 - 9 2 2 - 1 9 8 7 CE N T E R O F C O L O R A D O CA L L U T I L I T Y N O T I F I C A T I O N RE V I S I O N dr a w n b y : ch e c k e d b y : da t e : fi l e : HI G H C O U N T R Y E N G I N E E R I N G , I N C . PH O N E ( 9 7 0 ) 9 4 5 - 8 6 7 6 - F A X ( 9 7 0 ) 9 4 5 - 2 5 5 5 ww w . h c e n g . c o m 15 1 7 B L A K E A V E N U E , S T E 1 0 1 , GL E N W O O D S P R I N G S , C O 8 1 6 0 1 HC E HC E FE M A F L O O D P L A I N M A P AS P E N G R O V E S U B D I V I S I O N LO T 1 1 CI T Y O F A S P E N , C O . DI C K H A M P L E M A N FEMA 2181046.00 04/08/2021 EXHIBIT 4 HISTORIC DRAINAGE CONDITIONS 04/08/2021 BY NO . DA T E PROJECT NO. RE V I S I O N HI G H C O U N T R Y E N G I N E E R I N G , I N C . PH O N E ( 9 7 0 ) 9 4 5 - 8 6 7 6 - F A X ( 9 7 0 ) 9 4 5 - 2 5 5 5 ww w . h c e n g . c o m dr a w n b y : ch e c k e d b y : da t e : fi l e : 15 1 7 B L A K E A V E N U E , S T E 1 0 1 , GL E N W O O D S P R I N G S , C O 8 1 6 0 1 COLORADO 811 CALL BEFORE YOU DIG Utility Notification Center of Colorado 2181046.00 DI C K H A M P L E M A N CI T Y O F A S P E N , C O LO T 1 1 AS P E N G R O V E S U B D I V I S I O N MG G MG G 08 / 2 1 / 1 9 1 05 / 1 4 / 2 0 PE R M I T S U B M I T T A L MG G EXDR EX I S T I N G DR A I N A G E B A S I N M A P 04/08/2021 EXHIBIT 5 PROPOSED DRAINAGE CONDITIONS 04/08/2021 BY NO . DA T E PROJECT NO. RE V I S I O N HI G H C O U N T R Y E N G I N E E R I N G , I N C . PH O N E ( 9 7 0 ) 9 4 5 - 8 6 7 6 - F A X ( 9 7 0 ) 9 4 5 - 2 5 5 5 ww w . h c e n g . c o m dr a w n b y : ch e c k e d b y : da t e : fi l e : 15 1 7 B L A K E A V E N U E , S T E 1 0 1 , GL E N W O O D S P R I N G S , C O 8 1 6 0 1 COLORADO 811 CALL BEFORE YOU DIG Utility Notification Center of Colorado 2181046.00 DI C K H A M P L E M A N CI T Y O F A S P E N , C O LO T 1 1 AS P E N G R O V E S U B D I V I S I O N MG G MG G 08 / 2 1 / 1 9 1 05 / 1 4 / 2 0 PE R M I T S U B M I T T A L MG G PRDR PR O P O S E D DR A I N A G E B A S I N M A P 04/08/2021 EXHIBIT 6 DETAIL SHEET 04/08/2021 BY NO . DA T E PROJECT NO. RE V I S I O N HI G H C O U N T R Y E N G I N E E R I N G , I N C . PH O N E ( 9 7 0 ) 9 4 5 - 8 6 7 6 - F A X ( 9 7 0 ) 9 4 5 - 2 5 5 5 ww w . h c e n g . c o m dr a w n b y : ch e c k e d b y : da t e : fi l e : 15 1 7 B L A K E A V E N U E , S T E 1 0 1 , GL E N W O O D S P R I N G S , C O 8 1 6 0 1 COLORADO 811 CALL BEFORE YOU DIG Utility Notification Center of Colorado 2181046.00 DI C K H A M P L E M A N CI T Y O F A S P E N , C O LO T 1 1 AS P E N G R O V E S U B D I V I S I O N MG G MG G 08 / 2 1 / 1 9 1 05 / 1 4 / 2 0 PE R M I T S U B M I T T A L MG G C401 SH E E T 2 MI S C E L L A N E O U S D E T A I L S 04/08/2021 EXHIBIT 7 SOILS REPORT 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 04/08/2021 HYDROLOGIC COMPUTATIONS HISTORIC CONDITIONS PROPOSED CONDITIONS DETENTION CALCULATIONS 04/08/2021 LOT 11 ASPEN GROVE SUBDIVISION DRAINAGE REPORT BY: MGG CHECKED BY: MGG DATE: 12-19-18 EX-1 15,913 0.365 0 0.0 0.08 0.15 0.35 EX-OS1 42,013 0.964 0 0.0 0.08 0.15 0.35 EX-OS2 34,146 0.784 0 0.0 0.08 0.15 0.35 TOTAL ON-SITE 57,926 1.330 0 0.0 0.08 0.15 0.35 Type B Soils 5 YR RUNOFF COEFFICIENT 10 YR RUNOFF COEFFICIENT 100 YR RUNOFF COEFFICIENTPERCENT IMPERVIOUSBASIN AREA (S.F.) AREA (ACRE) IMPERVIOUS AREA (SF) 04/08/2021 LOT 11 ASPEN GROVE SUBDIVISION DRAINAGE REPORT BY: MGG CHECKED BY: MGG DATE: 12-19-18 REACH I P1-5yr P1-100yr Td EX-1 2.47 0.64 9.7 EX-1 4.76 1.23 9.7 I P1-5yr P1-100yr Td EX-OS1 2.04 0.64 13.7 EX-OS2 3.92 1.23 13.7 Tc Tc Tc I P1-5yr P1-100yr Td EX-OS1 1.75 0.64 17.3 5 YEAR INTENSITY EX-OS2 3.37 1.23 17.3 100 YEAR INTENSITY To = [0.395 (1.1 - C5) SQRT(L)] / (S0.333) EQUATION 3-4 C= 5 YR runoff coefficient from City of Aspen Urban Runoff Management Plan V=K*SQRT(S) Tc=To+Tt INTENSITY I=(88.8xP1) / (10+Td)1.052 EQUATION 2-1 P TAKEN FROM TABLES 2.2 AND 2.3 17.3 10.7 (MIN) EX-1 3.37 EX-OS2 1.75 4.76 2.47 5.0MINIMUM 5 MINUTES 9.7 FLOW VELOCITY, V (fps.) Tt = L/(60V) (min.) URBAN CHECK = 10+L/180 BASIN 0.0 FLOW LENGTH, L (TOTAL <300 FT.) (ft.) LAND SLOPE, S (ft./ft.) To (MIN) 0.00 SURFACE DESCRIPTION CONVEYANCE COEFFICIENT, K (TABLE 3.3 URMP) Rainfall Intenstity Chart EX-1EX-OS2 0.08 12.6 137 0.1450 Rainfall Intenstity Chart EX-OS1 0.1250 AREA IDENTIFIER 0.1650 246 300 11.3OV E R L A N D FL O W TR A V E L T I M E FLOW SLOPE, S (ft./ft.) RATIONAL COEFFICIENT. C (FIGURE 3.2 OF URMP) 3.92 5.0 EX-OS1 0.108 9.7 2.04 0.235 0.08 FLOW LENGTH, L (ft.) Meadow 12.4 5.0 13.0 0.95 2.4 13.7 0.88 4.6 EX-1 132.6 300 EX-OS1 0.08 Rainfall Intenstity Chart EX-OS2 2.5 2.5 Meadow 04/08/2021 CALCULATED BY: MGG STANDARD FORM SF-3 DATE: 12-19-18 STORM DRAINAGE SYSTEM DESIGN CHECKED BY: MGG (RATIONAL METHOD PROCEDURE) Contributing Area AR E A ( A C ) RU N O F F C O E F F . Tc ( M I N ) C * A ( A C ) I ( I N / H R ) Q ( C F S ) Tc ( M I N ) SU M ( C * A ) ( A C ) I ( I N / H R ) Q ( C F S ) SL O P E ( % ) CH A N N E L F L O W (C F S ) DE S I G N F L O W (C F S ) SL O P E ( % ) PI P E S I Z E ( I N C H E S ) LE N G T H ( F T ) VE L O C I T Y ( F P S ) Tt ( M I N ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) DESIGN POINT 1 DESIGN POINT 2 DESIGN POINT 3 0.082 0.08 CHANNEL 2.04 DE S I G N P O I N T DIRECT RUNOFF 0.08 9.71 EX-1 0.07 PROJECT: LOT 11 ASPEN GROVE JOB NO. 2181046.00 PIPE DESIGN STORM: EXISTING 5 YEAR TRAVEL TIME REMARKS 1.75 0.11 13.7 2.47 3 EX-OS2 0.784 0.08 STRUCTURE NO. 0.964EX-OS1 TOTAL RUNOFF 0.365 0.16 0.03 17.3 0.06 04/08/2021 CALCULATED BY: MGG STANDARD FORM SF-3 DATE: 12-19-18 STORM DRAINAGE SYSTEM DESIGN CHECKED BY: MGG (RATIONAL METHOD PROCEDURE) Contributing Area AR E A ( A C ) RU N O F F C O E F F . Tc ( M I N ) C * A ( A C ) I ( I N / H R ) Q ( C F S ) Tc ( M I N ) SU M ( C * A ) ( A C ) I ( I N / H R ) Q ( C F S ) SL O P E ( % ) CH A N N E L F L O W (C F S ) DE S I G N F L O W (C F S ) SL O P E ( % ) PI P E S I Z E ( I N C H E S ) LE N G T H ( F T ) VE L O C I T Y ( F P S ) Tt ( M I N ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) DESIGN POINT 1 DESIGN POINT 2 DESIGN POINT 3 EX-OS1 0.964 0.35 1.32213.7 0.34 3.92 JOB NO. 2181046.00 PROJECT: LOT 11 ASPEN GROVE DESIGN STORM: EXISTING 100 YEAR STRUCTURE NO. DE S I G N P O I N T DIRECT RUNOFF TOTAL RUNOFF CHANNEL PIPE TRAVEL TIME REMARKS 1 EX-1 0.365 0.35 9.7 0.13 4.76 0.61 3 EX-OS2 0.784 0.35 17.3 0.27 3.37 0.92 04/08/2021 LOT 11 ASPEN GROVE SUBDIVISION DRAINAGE REPORT BY: MGG CHECKED BY: MGG DATE: 12-19-18 PR-1 2,230 0.051 1,633 73.2 73.2 0.149 27.7 0.52 0.64 PR-2 8,552 0.196 1,754 20.5 20.5 0.049 34.9 0.20 0.44 PR-3 5,131 0.118 0 0.0 0.0 0.000 0.0 0.08 0.35 PR-OS1 42,012 0.964 7,289 17.3 0.17 0.43 PR-OS2 34,145 0.784 3,484 10.2 0.14 0.41 Onsite Only 15,913 0.248 3,387 21.3 0.198 62.6 PR-1 BP-1 0.149 27.7 PR-2 BP-2 0.049 34.9 WQCV (CF) TYPE B SOILS BASIN AREA (S.F.) AREA (ACRE) IMPERVIOUS AREA (SF) PERCENT IMPERVIOUS 10 YR RUNOFF COEFFICIENT 100 YR RUNOFF COEFFICIENT WQCV (Watershed inches) WQCV (CF) 5 YR RUNOFF COEFFICIENT EFFECTIVE IMPERVIOUS (% ) BASIN BIORETENTION WQCV (Watershed 04/08/2021 LOT 11 ASPEN GROVE SUBDIVISION DRAINAGE REPORT BY: MGG CHECKED BY: MGG DATE: 12-19-18 REACH Basin I P1-5yr P1-100yr Td PR-1 3.29 0.64 5.0 PR-1 6.33 1.23 5.0 Basin I P1-5yr P1-100yr Td PR-2 3.29 0.64 5.0 PR-2 6.33 1.23 5.0 Tc Tc Tc Basin I P1-5yr P1-100yr Td PR-OS1 3.08 0.64 6.0 5 YEAR INTENSITY PR-OS1 5.93 1.23 6.0 100 YEAR INTENSITY To = [0.395 (1.1 - C5) SQRT(L)] / (S0.333) EQUATION 3-4 Basin I P1-5yr P1-100yr Td C= 5 YR runoff coefficient from City of Aspen Urban Runoff Management Plan V=K*SQRT(S)PR-OS1 1.96 0.64 14.6 Tc=To+Tt PR-OS1 3.76 1.23 14.6 INTENSITY I=(88.8xP1) / (10+Td)1.052 EQUATION 2-1 P TAKEN FROM TABLES 2.2 AND 2.3 WITHIN THE URMP Rainfall Intenstity Chart OS-OS2 *INTENSITIES TAKEN FROM FIGURE 2.1 "IDF CURVES FOR ASPEN, COLORADO" FROM URMP Basin I P1-5yr P1-100yr Td PR-OS2 1.80 0.64 16.6 PR-OS2 3.46 1.23 16.6 Rainfall Intenstity Chart PR-2 Rainfall Intenstity Chart PR-3 15.0 2.5 2.5 5.05.0 0.0 11.0 Grass Swale Meadow Meadow 0.16 5.0 0.00 0.089 3.9 0.5 152.0 (MIN) Tt = L/(60V) (min.) URBAN CHECK = 10+L/180 PR-2 10.3 0.20 25.0 PR-1 57.0 RATIONAL COEFFICIENT. C (FIGURE 3.2 OF URMP) 0.52 AREA IDENTIFIER 3.3 BASIN MINIMUM 5 MINUTES 6.33 PR-1 3.29 OV E R L A N D FL O W FLOW VELOCITY, V (fps.) FLOW LENGTH, L (ft.) TR A V E L T I M E SURFACE DESCRIPTION FLOW LENGTH, L (TOTAL <300 FT.) (ft.) LAND SLOPE, S (ft./ft.) CONVEYANCE COEFFICIENT, K (TABLE 3.3 URMP) FLOW SLOPE, S (ft./ft.) To (MIN) 5.0 0.118 5.15 PR-OS1 3.766.33 PR-2 3.29 5.0 1.96 PR-OS1 0.00 300 0.235 12.2 137 Rainfall Intenstity Chart PR-1 0.1450 2.4 14.6 12.4 0.95 5.0 PR-OS2 0.14 300 0.1650 12.0 246 PR-OS2 1.80 Rainfall Intenstity Chart PR-OS1 3.46 0.1250 0.88 4.6 16.6 13.0 PR-3 0.08 49.0 0.106 6.0 0.00 0.0 6.0 10.3 5.0 PR-3 3.08 5.93 04/08/2021 CALCULATED BY: MGG STANDARD FORM SF-3 DATE: 12-19-18 STORM DRAINAGE SYSTEM DESIGN CHECKED BY: MGG (RATIONAL METHOD PROCEDURE) Contributing Area AR E A ( A C ) RU N O F F C O E F F . Tc ( M I N ) C * A ( A C ) I ( I N / H R ) Q ( C F S ) Tc ( M I N ) SU M ( C * A ) ( A C ) I ( I N / H R ) Q ( C F S ) SL O P E ( % ) ST R E E T F L O W ( C F S ) DE S I G N F L O W ( C F S ) SL O P E ( % ) PI P E S I Z E ( I N C H E S ) LE N G T H ( F T ) VE L O C I T Y ( F P S ) Tt ( M I N ) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) Design Piont 3 (1) 0.009 3.08 0.033 PR-3 0.118 0.08 6.0 0.320.164 1.96 Design Piont 4 Design Piont 2 3 PR-OS1 0.964 0.17 14.6 0.09 0.039 3.29 0.132 PR-2 0.196 0.20 5.0 Design Point 1 TRAVEL TIME REMARKS 1 PR-1 0.051 0.52 5.0 0.03 3.29 JOB NO. 2181046.00 PROJECT: LOT 11 ASPEN GROVE DESIGN STORM: PROPOSED 5 YEAR STRUCTURE NO. DE S I G N P O I N T DIRECT RUNOFF TOTAL RUNOFF STREET PIPE 4 PR-OS2 0.784 0.14 16.6 Design Piont 50.110 1.80 0.20 04/08/2021 CALCULATED BY: MGG STANDARD FORM SF-3 DATE: 12-19-18 STORM DRAINAGE SYSTEM DESIGN CHECKED BY: MGG (RATIONAL METHOD PROCEDURE) Contributing Area AR E A ( A C ) RU N O F F C O E F F . Tc ( M I N ) C * A ( A C ) I ( I N / H R ) Q ( C F S ) Tc ( M I N ) SU M ( C * A ) ( A C ) I ( I N / H R ) Q ( C F S ) SL O P E ( % ) ST R E E T F L O W ( C F S ) DE S I G N F L O W ( C F S ) SL O P E ( % ) PI P E S I Z E ( I N C H E S ) LE N G T H ( F T ) VE L O C I T Y ( F P S ) Tt ( M I N ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18)(19) (20) (21) (22) Design Piont 30.041 5.93 0.243 PR-3 0.118 0.35 6.0 1.56 Design Piont 4 Design Piont 2 4 PR-OS1 0.964 0.43 14.6 0.415 3.76 0.086 6.33 0.552 PR-2 0.196 0.44 5.0 0.21 Design Point 1 TRAVEL TIME REMARKS 1 PR-1 0.051 0.64 5.0 0.03 6.33 JOB NO. 2181046.00 PROJECT: LOT 11 ASPEN GROVE DESIGN STORM: PROPOSED 100 YEAR STRUCTURE NO. DE S I G N P O I N T DIRECT RUNOFF TOTAL RUNOFF STREET PIPE 5 PR-OS2 0.784 0.41 16.6 Design Piont 50.321 3.46 1.11 04/08/2021 Event 5yr Basin PR-1 - PR-3 A 0.365 ac tc 6 min P1 0.64 in Q5-EX 0.07 cfs C 0.2 Duration (td) (min.) Intensity (in/hr) Inflow Vol Vi (cf) Outflow Vol Vo (cf) Detention Vol Vd (cf) 5 3.29 72.68 23.10 49.58 8 2.72 95.99 29.40 66.59 11 2.31 112.22 35.70 76.52 14 2.01 124.11 42.00 82.11 17 1.77 133.15 48.30 84.85 20 1.59 140.21 54.60 85.61 23 1.44 145.86 60.90 84.96 26 1.31 150.46 67.20 83.26 29 1.20 154.27 73.50 80.77 32 1.11 157.46 79.80 77.66 35 1.04 160.16 86.10 74.06 38 0.97 162.48 92.40 70.08 85.61 RATIONAL VOLUME METHOD FOR DETENTION VOLUME Required Detention Vol (cf) Project Name: 312 McSkimming Project No: 2181047.00 By: MGG Date: 11/3/20 Project Name: 334 McSkimming Project No: 2181046.00 By: MGG Date: 12/23/20 EQUATIONS PER URMP CHAPTER 5.6.1 - DETENTION Equation 2-1 Equation 5-2 Equation 5-3 Equation 5-4 04/08/2021 Event 100 yr Basin PR-1 - PR-3 A 0.365 ac tc 6 min P1 1.23 in Q100-EX 0.61 cfs C 0.44 Duration (td) (min.) Intensity (in/hr) Inflow Vol Vi (cf) Outflow Vol Vo (cf) Detention Vol Vd (cf) 6 5.91 344.54 219.60 124.94 7 5.54 377.12 237.90 139.22 8 5.22 405.85 256.20 149.65 9 4.93 431.33 274.50 156.83 10 4.67 454.08 292.80 161.28 11 4.44 474.50 311.10 163.40 12 4.23 492.91 329.40 163.51 13 4.03 509.59 347.70 161.89 14 3.86 524.76 366.00 158.76 15 3.70 538.61 384.30 154.31 16 3.55 551.30 402.60 148.70 17 3.41 562.95 420.90 142.05 163.51 RATIONAL VOLUME METHOD FOR DETENTION VOLUME Required Detention Vol (cf) EQUATIONS PER URMP CHAPTER 5.6.1 ‐ DETENTION Equation 2-1 Equation 5-2 Equation 5-3 Equation 5-4 Project Name: 334 McSkimming Project No: 2181046.00 By: MGG Date: 12/23/20 04/08/2021 HYDRAULIC COMPUTATIONS STORM SEWER CALCULATIONS SWALE CALCULATIONS TRENCH DRAIN CALCULATIONS BIORETENTION POND CALCULATIONS 04/08/2021 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jun 12 2019 DRIVEWAY STORM SEWER 5-YR Circular Diameter (ft) = 0.67 Invert Elev (ft) = 8114.00 Slope (%) = 1.03 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 0.03 Highlighted Depth (ft) = 0.07 Q (cfs) = 0.030 Area (sqft) = 0.02 Velocity (ft/s) = 1.52 Wetted Perim (ft) = 0.44 Crit Depth, Yc (ft) = 0.08 Top Width (ft) = 0.41 EGL (ft) = 0.11 0 1 Elev (ft)Section 8113.75 8114.00 8114.25 8114.50 8114.75 8115.00 Reach (ft) 04/08/2021 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jun 12 2019 DRIVEWAY STORM SEWER 100-YR Circular Diameter (ft) = 0.67 Invert Elev (ft) = 8114.00 Slope (%) = 1.03 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 0.18 Highlighted Depth (ft) = 0.17 Q (cfs) = 0.180 Area (sqft) = 0.07 Velocity (ft/s) = 2.53 Wetted Perim (ft) = 0.71 Crit Depth, Yc (ft) = 0.20 Top Width (ft) = 0.58 EGL (ft) = 0.27 0 1 Elev (ft)Section 8113.75 8114.00 8114.25 8114.50 8114.75 8115.00 Reach (ft) 04/08/2021 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jun 12 2019 PR-2 SWALE 5-YR Triangular Side Slopes (z:1) = 10.00, 10.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 8115.25 Slope (%) = 2.80 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.57 Highlighted Depth (ft) = 0.19 Q (cfs) = 0.570 Area (sqft) = 0.36 Velocity (ft/s) = 1.58 Wetted Perim (ft) = 3.82 Crit Depth, Yc (ft) = 0.19 Top Width (ft) = 3.80 EGL (ft) = 0.23 0 2 4 6 8 10 12 14 16 18 20 22 24 Elev (ft)Depth (ft)Section 8114.50 -0.75 8115.00 -0.25 8115.50 0.25 8116.00 0.75 8116.50 1.25 8117.00 1.75 Reach (ft) 04/08/2021 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jun 12 2019 PR-2 SWALE 100-YR Triangular Side Slopes (z:1) = 10.00, 10.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 8115.25 Slope (%) = 2.80 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 2.55 Highlighted Depth (ft) = 0.33 Q (cfs) = 2.550 Area (sqft) = 1.09 Velocity (ft/s) = 2.34 Wetted Perim (ft) = 6.63 Crit Depth, Yc (ft) = 0.34 Top Width (ft) = 6.60 EGL (ft) = 0.42 0 2 4 6 8 10 12 14 16 18 20 22 24 Elev (ft)Depth (ft)Section 8114.50 -0.75 8115.00 -0.25 8115.50 0.25 8116.00 0.75 8116.50 1.25 8117.00 1.75 Reach (ft) 04/08/2021 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jun 12 2019 TRENCH DRAIN 5-YR Rectangular Bottom Width (ft) = 0.83 Total Depth (ft) = 0.56 Invert Elev (ft) = 8131.22 Slope (%) = 1.00 N-Value = 0.011 Calculations Compute by: Q vs Depth No. Increments = 20 Highlighted Depth (ft) = 0.03 Q (cfs) = 0.028 Area (sqft) = 0.02 Velocity (ft/s) = 1.19 Wetted Perim (ft) = 0.89 Crit Depth, Yc (ft) = 0.04 Top Width (ft) = 0.83 EGL (ft) = 0.05 0 .25 .5 .75 1 1.25 1.5 Elev (ft)Depth (ft)Section 8130.75 -0.47 8131.00 -0.22 8131.25 0.03 8131.50 0.28 8131.75 0.53 8132.00 0.78 Reach (ft) 04/08/2021 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jun 12 2019 TRENCH DRAIN 100-YR Rectangular Bottom Width (ft) = 0.83 Total Depth (ft) = 0.56 Invert Elev (ft) = 8131.22 Slope (%) = 1.00 N-Value = 0.011 Calculations Compute by: Known Q Known Q (cfs) = 0.18 Highlighted Depth (ft) = 0.10 Q (cfs) = 0.180 Area (sqft) = 0.08 Velocity (ft/s) = 2.17 Wetted Perim (ft) = 1.03 Crit Depth, Yc (ft) = 0.12 Top Width (ft) = 0.83 EGL (ft) = 0.17 0 .25 .5 .75 1 1.25 1.5 Elev (ft)Depth (ft)Section 8130.75 -0.47 8131.00 -0.22 8131.25 0.03 8131.50 0.28 8131.75 0.53 8132.00 0.78 Reach (ft) 04/08/2021 PR-1 PR-2 P1 BP-1 P2 BP-2 1L SITE DISCHARGE Routing Diagram for PR-SITE_5YR Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net, Printed 1/8/2021 HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 2HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment PR-1: Runoff = 0.09 cfs @ 0.09 hrs, Volume= 0.002 af, Depth= 0.57" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Rainfall Duration=20 min, Inten=3.29 in/hr Area (ac) C Description 0.051 0.52 C value from URMP runoff coefficient calc 0.051 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR-1: Runoff Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Rainfall Duration=20 min, Inten=3.29 in/hr Runoff Area=0.051 ac Runoff Volume=0.002 af Runoff Depth=0.57" Tc=5.0 min C=0.52 0.09 cfs 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 3HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment PR-2: Runoff = 0.13 cfs @ 0.09 hrs, Volume= 0.004 af, Depth= 0.22" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Rainfall Duration=20 min, Inten=3.29 in/hr Area (ac) C Description 0.196 0.20 C value from URMP runoff coefficient calc 0.196 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR-2: Runoff Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Rainfall Duration=20 min, Inten=3.29 in/hr Runoff Area=0.196 ac Runoff Volume=0.004 af Runoff Depth=0.22" Tc=5.0 min C=0.20 0.13 cfs 04/08/2021 Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment PR-3: Runoff = 0.03 cfs @ 0.10 hrs, Volume= 0.001 af, Depth= 0.09" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Rainfall Duration=20 min, Inten=3.29 in/hr Area (ac) C Description 0.118 0.08 C value from URMP runoff coefficient calc 0.118 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 04/08/2021 Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Subcatchment PR-3: Runoff Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Rainfall Duration=20 min, Inten=3.29 in/hr Runoff Area=0.118 ac Runoff Volume=0.001 af Runoff Depth=0.09" Tc=6.0 min C=0.08 0.03 cfs 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 4HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond P1: BP-1 Inflow Area = 0.051 ac, 0.00% Impervious, Inflow Depth = 0.57" Inflow = 0.09 cfs @ 0.09 hrs, Volume= 0.002 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Peak Elev= 8,115.84' @ 0.42 hrs Surf.Area= 183 sf Storage= 106 cf Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 8,115.00' 136 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 8,115.00 67 0 0 8,116.00 205 136 136 Device Routing Invert Outlet Devices #1 Primary 8,115.85'1.0' long x 0.7' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 Coef. (English) 2.76 2.82 2.93 3.09 3.18 3.22 3.27 3.30 3.32 3.31 3.32 Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=8,115.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 5HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Pond P1: BP-1 Inflow Primary Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.051 ac Peak Elev=8,115.84' Storage=106 cf 0.09 cfs 0.00 cfs 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 6HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Stage-Area-Storage for Pond P1: BP-1 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,115.00 67 0 8,115.02 70 1 8,115.04 73 3 8,115.06 75 4 8,115.08 78 6 8,115.10 81 7 8,115.12 84 9 8,115.14 86 11 8,115.16 89 12 8,115.18 92 14 8,115.20 95 16 8,115.22 97 18 8,115.24 100 20 8,115.26 103 22 8,115.28 106 24 8,115.30 108 26 8,115.32 111 29 8,115.34 114 31 8,115.36 117 33 8,115.38 119 35 8,115.40 122 38 8,115.42 125 40 8,115.44 128 43 8,115.46 130 45 8,115.48 133 48 8,115.50 136 51 8,115.52 139 53 8,115.54 142 56 8,115.56 144 59 8,115.58 147 62 8,115.60 150 65 8,115.62 153 68 8,115.64 155 71 8,115.66 158 74 8,115.68 161 77 8,115.70 164 81 8,115.72 166 84 8,115.74 169 87 8,115.76 172 91 8,115.78 175 94 8,115.80 177 98 8,115.82 180 101 8,115.84 183 105 8,115.86 186 109 8,115.88 188 112 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,115.90 191 116 8,115.92 194 120 8,115.94 197 124 8,115.96 199 128 8,115.98 202 132 8,116.00 205 136 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 7HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond P2: BP-2 Inflow Area = 0.196 ac, 0.00% Impervious, Inflow Depth = 0.22" Inflow = 0.13 cfs @ 0.09 hrs, Volume= 0.004 af Outflow = 0.00 cfs @ 0.42 hrs, Volume= 0.000 af, Atten= 97%, Lag= 19.7 min Primary = 0.00 cfs @ 0.42 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Peak Elev= 8,115.76' @ 0.42 hrs Surf.Area= 259 sf Storage= 156 cf Plug-Flow detention time= 33.1 min calculated for 0.000 af (2% of inflow) Center-of-Mass det. time= 22.0 min ( 34.5 - 12.5 ) Volume Invert Avail.Storage Storage Description #1 8,114.75' 306 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 8,114.75 81 0 0 8,115.75 225 153 153 8,116.00 1,000 153 306 Device Routing Invert Outlet Devices #1 Primary 8,115.75'1.0' long x 0.7' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 Coef. (English) 2.76 2.82 2.93 3.09 3.18 3.22 3.27 3.30 3.32 3.31 3.32 Primary OutFlow Max=0.00 cfs @ 0.42 hrs HW=8,115.76' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.00 cfs @ 0.29 fps) 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 8HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Pond P2: BP-2 Inflow Primary Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.196 ac Peak Elev=8,115.76' Storage=156 cf 0.13 cfs 0.00 cfs 04/08/2021 5-YR Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 9HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Stage-Area-Storage for Pond P2: BP-2 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,114.75 81 0 8,114.77 84 2 8,114.79 87 3 8,114.81 90 5 8,114.83 93 7 8,114.85 95 9 8,114.87 98 11 8,114.89 101 13 8,114.91 104 15 8,114.93 107 17 8,114.95 110 19 8,114.97 113 21 8,114.99 116 24 8,115.01 118 26 8,115.03 121 28 8,115.05 124 31 8,115.07 127 33 8,115.09 130 36 8,115.11 133 38 8,115.13 136 41 8,115.15 139 44 8,115.17 141 47 8,115.19 144 50 8,115.21 147 52 8,115.23 150 55 8,115.25 153 59 8,115.27 156 62 8,115.29 159 65 8,115.31 162 68 8,115.33 165 71 8,115.35 167 75 8,115.37 170 78 8,115.39 173 81 8,115.41 176 85 8,115.43 179 88 8,115.45 182 92 8,115.47 185 96 8,115.49 188 99 8,115.51 190 103 8,115.53 193 107 8,115.55 196 111 8,115.57 199 115 8,115.59 202 119 8,115.61 205 123 8,115.63 208 127 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,115.65 211 131 8,115.67 213 135 8,115.69 216 140 8,115.71 219 144 8,115.73 222 149 8,115.75 225 153 8,115.77 287 158 8,115.79 349 164 8,115.81 411 172 8,115.83 473 181 8,115.85 535 191 8,115.87 597 202 8,115.89 659 215 8,115.91 721 229 8,115.93 783 244 8,115.95 845 260 8,115.97 907 278 8,115.99 969 296 04/08/2021 Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Link 1L: SITE DISCHARGE Inflow Area = 0.365 ac, 0.00% Impervious, Inflow Depth > 0.03" Inflow = 0.03 cfs @ 0.10 hrs, Volume= 0.001 af Primary = 0.03 cfs @ 0.10 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs 04/08/2021 Rainfall Duration=20 min, Inten=3.29 in/hrPR-SITE_5YR Printed 1/8/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Link 1L: SITE DISCHARGE Inflow Primary Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.365 ac 0.03 cfs0.03 cfs 04/08/2021 PR-1 PR-2 P1 BP-1 P2 BP-2 1L SITE DISCHARGE Routing Diagram for PR-SITE_100YR Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net, Printed 1/7/2021 HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 2HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment PR-1: Runoff = 0.21 cfs @ 0.09 hrs, Volume= 0.003 af, Depth= 0.81" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Rainfall Duration=12 min, Inten=6.33 in/hr Area (ac) C Description 0.051 0.64 C value from URMP runoff coefficient calc 0.051 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR-1: Runoff Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Rainfall Duration=12 min, Inten=6.33 in/hr Runoff Area=0.051 ac Runoff Volume=0.003 af Runoff Depth=0.81" Tc=5.0 min C=0.64 0.21 cfs 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 3HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment PR-2: Runoff = 0.55 cfs @ 0.09 hrs, Volume= 0.009 af, Depth= 0.56" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Rainfall Duration=12 min, Inten=6.33 in/hr Area (ac) C Description 0.196 0.44 C value from URMP runoff coefficient calc 0.196 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR-2: Runoff Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Rainfall Duration=12 min, Inten=6.33 in/hr Runoff Area=0.196 ac Runoff Volume=0.009 af Runoff Depth=0.56" Tc=5.0 min C=0.44 0.55 cfs 04/08/2021 Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment PR-3: Runoff = 0.26 cfs @ 0.10 hrs, Volume= 0.004 af, Depth= 0.44" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Rainfall Duration=12 min, Inten=6.33 in/hr Area (ac) C Description 0.118 0.35 C value from URMP runoff coefficient calc 0.118 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 04/08/2021 Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Subcatchment PR-3: Runoff Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Rainfall Duration=12 min, Inten=6.33 in/hr Runoff Area=0.118 ac Runoff Volume=0.004 af Runoff Depth=0.44" Tc=6.0 min C=0.35 0.26 cfs 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 4HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond P1: BP-1 Inflow Area = 0.051 ac, 0.00% Impervious, Inflow Depth = 0.81" Inflow = 0.21 cfs @ 0.09 hrs, Volume= 0.003 af Outflow = 0.11 cfs @ 0.24 hrs, Volume= 0.001 af, Atten= 49%, Lag= 9.1 min Primary = 0.11 cfs @ 0.24 hrs, Volume= 0.001 af Routing by Stor-Ind method, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Peak Elev= 8,115.96' @ 0.24 hrs Surf.Area= 200 sf Storage= 129 cf Plug-Flow detention time= 13.3 min calculated for 0.001 af (28% of inflow) Center-of-Mass det. time= 9.1 min ( 17.6 - 8.5 ) Volume Invert Avail.Storage Storage Description #1 8,115.00' 136 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 8,115.00 67 0 0 8,116.00 205 136 136 Device Routing Invert Outlet Devices #1 Primary 8,115.85'1.0' long x 0.7' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 Coef. (English) 2.76 2.82 2.93 3.09 3.18 3.22 3.27 3.30 3.32 3.31 3.32 Primary OutFlow Max=0.11 cfs @ 0.24 hrs HW=8,115.96' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.11 cfs @ 0.93 fps) 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 5HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Pond P1: BP-1 Inflow Primary Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.051 ac Peak Elev=8,115.96' Storage=129 cf 0.21 cfs 0.11 cfs 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 6HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Stage-Area-Storage for Pond P1: BP-1 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,115.00 67 0 8,115.02 70 1 8,115.04 73 3 8,115.06 75 4 8,115.08 78 6 8,115.10 81 7 8,115.12 84 9 8,115.14 86 11 8,115.16 89 12 8,115.18 92 14 8,115.20 95 16 8,115.22 97 18 8,115.24 100 20 8,115.26 103 22 8,115.28 106 24 8,115.30 108 26 8,115.32 111 29 8,115.34 114 31 8,115.36 117 33 8,115.38 119 35 8,115.40 122 38 8,115.42 125 40 8,115.44 128 43 8,115.46 130 45 8,115.48 133 48 8,115.50 136 51 8,115.52 139 53 8,115.54 142 56 8,115.56 144 59 8,115.58 147 62 8,115.60 150 65 8,115.62 153 68 8,115.64 155 71 8,115.66 158 74 8,115.68 161 77 8,115.70 164 81 8,115.72 166 84 8,115.74 169 87 8,115.76 172 91 8,115.78 175 94 8,115.80 177 98 8,115.82 180 101 8,115.84 183 105 8,115.86 186 109 8,115.88 188 112 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,115.90 191 116 8,115.92 194 120 8,115.94 197 124 8,115.96 199 128 8,115.98 202 132 8,116.00 205 136 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 7HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond P2: BP-2 Inflow Area = 0.196 ac, 0.00% Impervious, Inflow Depth = 0.56" Inflow = 0.55 cfs @ 0.09 hrs, Volume= 0.009 af Outflow = 0.22 cfs @ 0.25 hrs, Volume= 0.004 af, Atten= 60%, Lag= 9.6 min Primary = 0.22 cfs @ 0.25 hrs, Volume= 0.004 af Routing by Stor-Ind method, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs Peak Elev= 8,115.93' @ 0.25 hrs Surf.Area= 824 sf Storage= 337 cf Plug-Flow detention time= 15.3 min calculated for 0.004 af (41% of inflow) Center-of-Mass det. time= 11.9 min ( 20.4 - 8.5 ) Volume Invert Avail.Storage Storage Description #1 8,114.75' 396 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 8,114.75 139 0 0 8,115.75 323 231 231 8,116.00 1,000 165 396 Device Routing Invert Outlet Devices #1 Primary 8,115.75'1.0' long x 0.7' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 Coef. (English) 2.76 2.82 2.93 3.09 3.18 3.22 3.27 3.30 3.32 3.31 3.32 Primary OutFlow Max=0.22 cfs @ 0.25 hrs HW=8,115.93' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.22 cfs @ 1.19 fps) 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 8HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Pond P2: BP-2 Inflow Primary Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.196 ac Peak Elev=8,115.93' Storage=337 cf 0.55 cfs 0.22 cfs 04/08/2021 100-YR Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 9HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Stage-Area-Storage for Pond P2: BP-2 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,114.75 139 0 8,114.77 143 3 8,114.79 146 6 8,114.81 150 9 8,114.83 154 12 8,114.85 157 15 8,114.87 161 18 8,114.89 165 21 8,114.91 168 25 8,114.93 172 28 8,114.95 176 31 8,114.97 179 35 8,114.99 183 39 8,115.01 187 42 8,115.03 191 46 8,115.05 194 50 8,115.07 198 54 8,115.09 202 58 8,115.11 205 62 8,115.13 209 66 8,115.15 213 70 8,115.17 216 75 8,115.19 220 79 8,115.21 224 83 8,115.23 227 88 8,115.25 231 93 8,115.27 235 97 8,115.29 238 102 8,115.31 242 107 8,115.33 246 112 8,115.35 249 117 8,115.37 253 122 8,115.39 257 127 8,115.41 260 132 8,115.43 264 137 8,115.45 268 142 8,115.47 271 148 8,115.49 275 153 8,115.51 279 159 8,115.53 283 164 8,115.55 286 170 8,115.57 290 176 8,115.59 294 182 8,115.61 297 188 8,115.63 301 194 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8,115.65 305 200 8,115.67 308 206 8,115.69 312 212 8,115.71 316 218 8,115.73 319 225 8,115.75 323 231 8,115.77 377 238 8,115.79 431 246 8,115.81 485 255 8,115.83 540 266 8,115.85 594 277 8,115.87 648 289 8,115.89 702 303 8,115.91 756 317 8,115.93 810 333 8,115.95 865 350 8,115.97 919 368 8,115.99 973 387 04/08/2021 Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Link 1L: SITE DISCHARGE Inflow Area = 0.365 ac, 0.00% Impervious, Inflow Depth > 0.30" Inflow = 0.50 cfs @ 0.23 hrs, Volume= 0.009 af Primary = 0.50 cfs @ 0.23 hrs, Volume= 0.009 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-1.00 hrs, dt= 0.01 hrs 04/08/2021 Rainfall Duration=12 min, Inten=6.33 in/hrPR-SITE_100YR Printed 1/7/2021Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Link 1L: SITE DISCHARGE Inflow Primary Hydrograph Time (hours) 10 Fl o w ( c f s ) 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.365 ac 0.50 cfs0.50 cfs 04/08/2021 ASPEN CHARTS AND FIGURES 04/08/2021 www.hceng.com PHONE (970) 945-8676 FAX (970) 945-2555 1517 BLAKE AVENUE, STE 101, GLENWOOD SPRINGS, CO 81601 PHONE (303) 925-0544 FAX (303) 925-0547 14 INVERNESS DRIVE EAST, STE F-120, ENGLEWOOD, CO 80112 HIGH COUNTRY ENGINEERING, INC. file: date: checked by: drawn by: Project No: page: scale: 2181046.00 N.A. IDF Curves 8/21/19 MGG MGG CURVES INTENSITY DURATION FREQUENCY LOT 11 ASPEN GROVE SUB ASPEN, COLORADO DICK HAMPLEMAN 04/08/2021 www.hceng.com PHONE (970) 945-8676 FAX (970) 945-2555 1517 BLAKE AVENUE, STE 101, GLENWOOD SPRINGS, CO 81601 PHONE (303) 925-0544 FAX (303) 925-0547 14 INVERNESS DRIVE EAST, STE F-120, ENGLEWOOD, CO 80112 HIGH COUNTRY ENGINEERING, INC. file: date: checked by: drawn by: Project No: page: scale: 2181046.00 N.A. WQCV 8/21/19 MGG MGG CAPTURE VOLUME WATER QUALITY LOT 11 ASPEN GROVE SUB ASPEN, COLORADO DICK HAMPLEMAN 04/08/2021 www.hceng.com PHONE (970) 945-8676 FAX (970) 945-2555 1517 BLAKE AVENUE, STE 101, GLENWOOD SPRINGS, CO 81601 PHONE (303) 925-0544 FAX (303) 925-0547 14 INVERNESS DRIVE EAST, STE F-120, ENGLEWOOD, CO 80112 HIGH COUNTRY ENGINEERING, INC. file: date: checked by: drawn by: Project No: page: scale: 2181046.00 N.A. Runoff Coeff 8/21/19 MGG MGG RUNOFF COEFFICIENTS LOT 11 ASPEN GROVE SUB ASPEN, COLORADO DICK HAMPLEMAN 04/08/2021