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HomeMy WebLinkAboutFile Documents.905 Chatfield Rd.0111.2018 (77).ARBKPage 1 DRAINAGE REPORT FOR 905 CHATFIELD ROAD CITY OF ASPEN, COLORADO PARCEL ID: 273502402004 PREPARED FOR: CCY ARCHITECTS 228 Midland Ave, Basalt, CO 81621 PREPARED BY: High Country Engineering, Inc. 1517 Blake Avenue, Suite 101 Glenwood Springs, CO 81601 (970) 945-8676 March 15, 2018 Revised January 22, 2019 HCE JOB NUMBER: 2171053.00 02/14/2019 Reviewed by Engineering 02/22/2019 8:59:54 AM "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 TABLE OF CONTENTS SECTION PAGE I. GENERAL LOCATION AND DESCRIPTION OF SITE 4 II. DRAINAGE STUDIES 5 III. DRAINAGE DESIGN CRITERIA 5 IV. DRAINAGE FACILITY DESIGN 5 V. CONCLUSION 11 VI. REFERENCES 11 EXHIBITS: 1. Vicinity Map (8.5”x11”) 2. FEMA FIRM Map 08097C0203C (11”x17”) 3. Soils Report HP Kumar Geotechnical Report, 2017 Subsoil Study 4. Web Soil Survey USDA NRCS Map 5. Existing Drainage Basin Map 6. Proposed Drainage Basin Map APPENDICES: Hydrologic Computations Existing Conditions Proposed Conditions Hydraulic Computations Detention Volume Calcs PR-1 and PR-2 Water Quality Vault and Detention Vault PR-1 South Bioretention Pond PR-2 North Bioretention Overflow Weir Calculations Pipe Sizing Hydraulic Grade Swale Sizing Nyloplast Inlet Calculations Aspen Charts and Figures 02/14/2019 Page 3 Engineers Certification “I hereby affirm that this report and the accompanying plans for the construction of driveway, patio, residence and general site improvements of 905 Chatfield Drive was prepared by me (or under my direct supervision) for the owners thereof in accordance with the provisions of the City of Aspen Urban Runoff Management Plan and approved variances are exceptions listed thereto. I understand that it is the policy of the City of Aspen that the City of Aspen does not and will not assume liability for drainage facilities designed by others.” License No. 38823 Romeo Baylosis, P.E. Licensed Professional Engineer, State of Colorado 1-22-2019 02/14/2019 Page 4 I. GENERAL LOCATION AND DESCRIPTION OF SITE A. Location The proposed site at 905 Chatfield Road, Lot 4, West Aspen Subdivision, Filing 3 is located southwest of the intersection of Silver King Drive and Homestake Drive. The site is northwest of the Aspen Golf Course Club House, within the City of Aspen, County of Pitkin, State of Colorado. A Vicinity Map has been included as Exhibit #1. B. Description of Property The proposed site is approximately 15,000 square feet +/- (0.34 acres). The existing lot consists of a 2 story existing home with decks, patios, retaining walls, lawn, sidewalk entry, and driveway that will be a tear down and replace. There are mature spruce and aspen throughout the property, manicured lawn and bushes. A tree removal map has already been created for the site by the Landscape Architect for exact tree types, sizes and removals. The remaining trees on the site will be protected from the proposed construction activities per the City Foresters recommendations. Homestake Drive runs east and west, directly east of the property. This is the main access road for the driveway leaving the site. The site currently picks up offsite flows from a small section of Homestake Drive, these flows will be directed through the site as historically occurred. C. Lot Soils Description Within the area of study, there is generally one type of soil per the attached geotechnical reports which define the subsoils as 3-4’ of “mixed clay, sand and gravel fill, consist of dense, silty to slightly silty sandy gravel with cobbles and probable boulders to the boring depths of 7-12’. Subsoil borings are described as “fill; Silty, clayey sandy gravel, moist, mixed brown and gravel; silty to slightly silty, sandy, cobbles, probable boulders, dense, slightly moist, brown, rounded rock.” Based on the NRCS, the soil type is designated as soil 107, Uracca, moist-Mergel complex, 1 to 6 percent slopes, having an HSG soil type “B” rating. The NRCS soil map is included as Exhibit 4. Under the URMP Chapter 3 definitions of soils types this site would fall into type “A” soils, but type “A” soils are not allowed to be used within the City of Aspen boundary. Due to the attached geotech reports and the Natural Resources Conservation Service (NRCS) mapping and more accurate information and gradations for the site specific soils a type “B” soil will be used for calculations. See Exhibit 3 for the soils report information. The site specific geotechnical and soil studies were completed by HP Kumar on December 26th, 2017, Project No. 17-7-830. Ground water was not encountered within the geotech borings of up to 12’ in depth. Percolation rates in the December 26th report vary from 120 inches per hour to 18.2 in/hr (0.5 – 3.3 minutes per inch). The percolation test was conducted in the 4-inch diameter borehole “B-1” on December 6, 2017 at a hole depth of 120 inches. The hydraulic conductivity of the soil sample is approximately 3x10-4 ft/s. The percolation rate show that the site is a great receptor to underground detention facilities capturing surface water that would now run off at an increased rate to the roadway or irrigation ditch to be able to percolate into the soils as in historic conditions. 02/14/2019 Page 5 D. Description of Project Goals The proposed project will consist of full site demolition including existing structures and features on the site and construction of a new residence on the lot. The site layout will include a new single family home, driveway, sidewalk, patios/pavers, and lawn. There will be no change to the overall site drainage patterns caused by this development. Homestake Drive drainage stays within the ROW to the east of the lot and flows to the north. The drainage on the site will travel around the home to the south and north, then west into the Maroon Creek drainage below. This is how the site currently is drained and historically drained. Peak runoff flow rates will be kept to historic rates. See attached basin maps for existing and proposed site layout (Exhibits 5 & 6). II. DRAINAGE STUDIES A. Major Basin Description The proposed site is located on FEMA’s Flood Insurance Rate Map (FIRM) No. 08097C0203C (Exhibit #2) which has an effective date of June 4, 1987. The site is located in Zone-X, this zone is described as areas determined to be outside 100-year and 500-year floodplains. There are no major drainage ways, facilities, or easements within the property boundary, nor are there any irrigation facilities that will impact the proposed construction. Mud flow mapping per the WRC Engineering report was analyzed for the site. This site is outside of the study area. The Mud Flow Zone mapping in the Storm Drainage Master Plan for the City of Aspen, Colorado by WRC Engineering, Inc. in November of 2001 was utilized for this section. B. Previous Drainage Studies There are no previous site specific drainage studies for the site. The proposed site is located outside of the Study Area Boundary for the “Storm Drainage Plan for the City of Aspen” by WRC Engineering, Inc. in November 2001 and outside of the 100-yr flooding locations denoted in the study. C. Receiving System and Effects of Adjacent Drainage Issues There are no drainage issues with the adjacent properties that affect the site. The site all flows to the west into the Maroon Homeplace LLC which is a 51 acre parcel and encompasses Maroon Creek within its boundary. Storm flows will make their way down the thick brush on the hillside and into the wetlands and the end of stage drive below that flows directly to Maroon Creek and the Roaring Fork River. III. DRAINAGE DESIGN CRITERIA 02/14/2019 Page 6 A. Criteria This drainage study was prepared in conformance with the City of Aspen, Colorado Urban Runoff Management Plan (URMP), dated December. 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 25-percent of the 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. grass). The offsite basins consisting of roadway, gravel parking and ROW grass areas were analyzed as existing (open space and impervious area) per the URMP. Water Quality Capture Volume (WQCV) will be determined for the site 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 in watershed inches x 1 ft/12 in x area (acres) x 43,560 ft2/acre. B. Hydrologic Criteria The hydrologic methods for this study are outlined in the URMP from the City of Aspen, Colorado (December, 2014) for the Rational Method. Hydrologic calculations were performed using the Rational Method hydrology model in Autodesk Storm and Sanitary Analysis. 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, 5-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 3.2 from the URMP was used to determine the runoff coefficients for the 2-year, 5- year, 10-year and 100-year storm events since the soils were determined to be type “B” soils. The Rational Method was used for detention volumes and determining historic versus proposed peak runoff flow rates. In accordance with Chapter 8 of the URMP design procedure and criteria, proposed BMP sizing was calculated for comparing the WQCV and the 100-year event runoff volume. The proposed above grade WQ and below grade detention structures were sized using the URMP rational method detention volume calculation equations. The stormwater vaults and bioretention pond have been sized to accommodate WQCV and detention for basin PR-1 and PR-2. The vaults on the south side of the property have been designed to hold the WQ and Detention requirements for basin PR-1. Bioretention pond on the north side of the property has been designed to hold the WQ and Detention requirements for basin PR-2. Type “B” soils were utilized for the site per the onsite geotechnical study and a percolation 02/14/2019 Page 7 rate of 3.3 min/inch was utilized for the facilities on the site. The below grade facilities will capture the runoff for the onsite 10-year and 100-year storm events through the vaults, and bioretention pond and percolation rates. The release structures for south basin is are pipes with orifice caps to release to a level spreading area and into the Maroon Creek basin below. 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 open channels, storm pipes, and inlets were sized using Autodesk Hydraflow Storm Sewers and Express Extensions for Civil 3D. A 50-percent clogging factor was multiplied by the 100-year discharge rate for proper grate sizing on all inlets as outlined in the URMP. D. Site Constraints Per City code vaults and drywells cannot be placed within 10’ of a structure. The proposed stormwater vaults are located more than 10’ from the building foundation and the proposed bioretention is designed with an impervious liner and underdrain to eliminate percolation toward the structure. The size of the lot, setback requirements, easements and existing trees are all considered site constraints. The amount of actual surface area not taken up by these constraints and the proposed building limit the available locations for bioretention and detention facilities. The proposed design is focused around breaking up WQ and detention facilities into smaller areas and capturing and treating all the water prior to it leaving the site efficiently. E. Easements, Irrigation Facilities, Waterways There are no major drainage easements or tracts located on the site. There are standard zoning setbacks from property lines and utility easements along the property line. However, these easements do not affect the proposed site drainage design. IV. DRAINAGE FACILITY DESIGN A. Existing Subbasins The existing site’s historic drainage patterns are from southeast to northwest, then flow offsite to the west. Onsite flows drain from southeast to northwest on the property. Runoff from the Homestake Drive crown drains toward Chatfield Road, then flows north along Chatfield Road. There is a grade break in the ROW on the west side of Chatfield Road that redirects the offsite flow northwest from Homestake Drive. The offsite flows from Chatfield Road and Homestake Drive are conveyed in a northwest direction across the northeast corner of 905 Chatfield and through the adjacent neighboring property. Offsite flows mimic the existing drainage pattern and will bypass the site along the lawn, then past the northeast corner of 905 Chatfield Road. The existing historic surface area conditions were analyzed to determine the historic runoff 02/14/2019 Page 8 peak flow and calculate detention. The historic conditions encompass approximately 16,200 square feet (0.372 acres) and is assumed in the predevelopment conditions. The ground cover includes no structures and consists of steep to gently sloped range mixed with grass and brush. Historic impervious area is assumed to only include the paved asphalt surface of Chatfield Road and Homestake Drive. The difference in historic versus proposed conditions were evaluated to reduce peak runoff rates to historic rates and determine the amount of storm water quality and detention volume. Offsite flows do not contribute to the onsite flows that will be treated for water quality and detention. The historic site has been broken into two onsite drainage. Refer to sheet C-DR-EX, Existing Drainage Basins (Exhibit #5) for the existing basin map. Basin EX-1 encompasses approximately 2/3rds of the lot from the southern property line and drains to Design Point 1. Basin EX-2 encompasses the remaining 1/3rd of the lot up to the northern property line and drains to Design Point 2. Chatfield Road runs south to north of the home along the east front lot line. The flows from each existing onsite basin are analyzed versus the corresponding proposed basin to determine the required WQCV and detention. The existing historic peak runoff rate for each existing basin, as well as the entire site, are designed to provide WQCV and detention in the proposed basins to meet historic rates. Runoff from basin EX-1 sheet flows west, then to the west along the south side of the existing home and through the back yard to the northwest and into the Maroon Creek drainage. This flow converges with EX-2 flow at Design Point 1. Runoff from basin EX-2 sheet flows northwest across the front eastern property line, then to the west along the north side of the existing home and into the Maroon Creek drainage. This flow converges with EX-1 flow at Design Point 2. Table 1. Existing Basin Characteristics BASIN AREA SF IMPERVIOUS AREA SF C 10 YR I 10 YR Q10-YEAR CFS C 100 YR I 100 YR Q100-YEAR CFS EX-1 11900 0 0.15 3.72 0.15 0.35 6.32 0.60 EX-2 4300 0 0.15 3.72 0.06 0.35 6.32 0.22 ONSITE TOTAL 0.21 ONSITE TOTAL 0.82 The onsite flows pertain to the historic site flows only. Existing historic runoff peak flow rates from the site are analyzed versus the corresponding proposed basin. Release rate to Design Point 1 (northwest corner of lot) will be the analysis of EX-1 versus PR-1. Release rate to Design Point 2 (northwest of terrace and lawn) will be the analysis of EX-2 versus PR-2. B. Proposed Subbasins The proposed site has been separated into two proposed onsite drainage basins. Refer to sheet C-DR-PR Proposed Drainage Basins, Exhibit #6, in the exhibit section for the proposed basin map and drainage design. 02/14/2019 Page 9 Basin PR-1 consists of the majority of the home and southern property area including the building, roof, onsite driveway, front lawn and sidewalk to the main entry. The south side of the home and the majority of the roof and patios drain to the proposed stormwater vaults. The driveway is proposed impervious paving which sheet flows to a trench drain that is piped to the stormwater quality and detention vaults. The east side of the proposed garage and main entry represent a terrain trap, therefore, a factor of safety is designed for the stormwater facilities draining the east half of Basin PR-1. Storm structures and pipes are designed to convey the 100-year event for the entire PR-1 to protect the property. The water quality and detention vaults are separate underground structures. Water Quality Vault “A” provides temporary ponding in the pretreatment chamber, then captures the WQCV in the sand filter and percolation chamber. Outflow from Water Quality Vault “A” is conveyed to Detention Vault “B”. The WQCV for this basin was calculated at 102 CF. Pretreatment of 31 CF (0.3x103) is captured in the water quality vault’s pretreatment chamber, and 103 CF is captured in the WQCV chamber. By restricting the 100-yr storm runoff rate in Basin PR-1 to the historic release rate of 0.60 cfs, the required detention is 125 CF in Detention Vault “B”. The detention vault captures 125 CF with a ponding depth of 3.3 feet. Additional detention volume is available in the vault’s filter material, but is conservatively negligible. Furthermore, no infiltration is attributed to the percolation rate of 18.2 inches/hour (3.3 minutes/inch) which provides additional reduction for percolation volume. Detention Vault “B” includes a 100-year orifice control outlet restricting the proposed runoff rate to the historic release rate. The orifice releases runoff at the historic rate to outlet pipes which convey major flows exceeding the 100-yr storm west and offsite into the Maroon Creek Drainage. The control outlet consist of two 8” diameter ADS N-12 culverts with a 6” diameter orifice cap attached to each outflow culvert to daylight. The vault outfall includes a level spreading mechanism consisting of the two 8” diameter culverts routed to a level spreading perforated pipe encased in concrete. The maximum velocity in the culverts for the 100-year storm threshold is calculated to be 1.9 feet per second. The level spreader will further dissipate overflows over the length of the perforated pipe. Basin PR-2 consists of the smaller portion of the home and northern property area including the building, roof and lawn. Roof drains are routed to the home’s north side then conveyed to a swale that flows along the north side to the proposed bioretention pond area. The swale conveys flow to Bioretention Pond “A” for stormwater quality treatment and detention. The WQCV for this basin was calculated at 20.4 CF. WQCV provided is 21 CF within the rain garden, growing media and filter material. By restricting the 100-yr storm runoff rate in Basin PR-2 to the historic release rate of 0.22 cfs, the required detention is 12 CF in Bioretention Pond “A”. Due to the proximity to the structure, the pond is designed with 02/14/2019 Page 10 underdrains and an impermeable liner. The pond provides 28 CF of ponding water quality and detention volume above the growing media and 8 CF in the filter material voids. The pond provides a total volume of 36 CF including the pond volume and filter material voids. The pond utilizes underdrain piping with outlet orifice designed to restrict the peak outflow to historical rates after treating runoff in the rain garden growing media and filter material. The pond outlet also includes an outlet weir to convey major flows exceeding the 100-year storm west and offsite into the Maroon Creek drainage. The maximum headwater depth above the weir crest is calculated to be 0.13’ for events exceeding the 100-year storm. Table 2. Proposed Basin Characteristics BASIN AREA SF IMPERVIOUS AREA SF C 10 YR I 10 YR Q10-YEAR CFS C 100 YR I 100 YR Q100-YEAR CFS PR-1 13600 6230 0.39 3.72 0.45 0.51 6.32 1.01 PR-2 3500 1130 0.33 3.72 0.10 0.49 6.32 0.25 ONSITE TOTAL 0.55 ONSITE TOTAL 1.26 The impervious percentage for each basin was used to determine the WQCV in watershed inches on Figure 8.13. Level 1 adjustment was not used for any of the basins to be conservative since this site is very confined and has a minimal amount of release locations available. The 10-year and 100-year detention volume tables can be seen in the report appendices. Table 3. Proposed WQCV Table BASIN AREA (S.F.) IMPERVIOUS AREA (SF) PERCENT IMPERVIOUS WQCV (Watershed inches)WQCV (CF) PR-1 13600 6230 45.8%.09 102.0 PR-2 3500 1130 32.3%.07 20.4 Onsite 17100 7360 43.0%122.4 C. Low Impact Site Design The proposed site design incorporates low impact site design criteria from the URMP. Roof downspouts will drain to grassed swales, that will convey drainage to the proposed WQ/detention facilities. Unnecessary impervious areas were avoided, such as minimizing the driveway width and utilizing sand set stepping stones with grass joints throughout the project. The bioretention pond utilizes an underdrain system below the filter material which provides water quality and detention. A level spreader is incorporated at the water quality and detention vaults to mimic the historic drainage pattern and avoiding point discharge. All storm water produced by the site will be conveyed through the WQ/detention systems, thus reducing the transfer of pollutants to the existing irrigation ditch and ultimately Maroon Creek. 02/14/2019 Page 11 D. Operation and Maintenance The vaults will need to be inspected and cleared of rubbish and debris quarterly to make sure that the filter media has not become clogged and is functioning properly. The filter material will be cleaned or replaced as the material shows sign of clogging. The replacement of this material may occur every two to five years. The open end of the overflow pipe must also be inspected to make sure it has not clogged. Review of the overflow structure should occur at least every 6 months or after large storm events. The bioretention pond shall be inspected after large storm events to determine if the filter media is functioning properly and has not been washed away. If material becomes clogged, replacement material must be installed. The filter material will be cleaned or replaced as the material shows sign of clogging. The replacement of this material may occur every two to five years. Review of the overflow structure should occur at least every 6 months or after large storm events. The proposed area inlets shall be inspected and cleared of rubbish and debris quarterly as well as after large storm events. The inlet basin and sump shall be inspected to insure proper function while keeping a majority of the large particles from reaching downstream facilities. If debris is observed within any inlets, then the grates shall be removed and each basin shall be emptied and vacuumed clean to keep sediment from going to the vaults. The owners 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. V. CONCLUSION A. Compliance with Standards This drainage report has been prepared in accordance with City of Aspen Regulations. The proposed stormwater facilities will capture the WQCV as well detain site runoff before releasing to the top bluffs above Maroon Creek. Runoff leaving the site will be less than or equal to historic runoff rates. Runoff entering the stormwater facilities will not leave the property unless the storm exceeds major event frequency. The site’s design has been prepared to be in compliance with the City of Aspen’s URMP. B. Drainage Concept The proposed drainage system is designed to control any adverse downstream impacts on landowners or structures by conveying stormwater site similar to the existing pattern at levels less than or equal to historic runoff rates. Water quality will be addressed by capturing and treating pollutant laden runoff in stormwater quality and detention facilities. 02/14/2019 Page 12 VI. REFERENCES 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. HP Geotechnical, Inc. Subsoil Study For Foundation Design Proposed 905 Chatfield Road Drive, Aspen, Colorado. December 26th, 2017, Job number. HP Geotechnical, Inc. Percolation Testing for Drywell Design and Update of Previous Report, 1655 Silver King Drive, Aspen, Colorado. September 30th, 2014, Job number 17- 7-83. UDFCD. www.udfcd.org. 02/14/2019 EXHIBITS 02/14/2019 Site Exhibit 1 02/14/2019 SiteExhibit 202/14/2019 Exhibit 302/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 Hydrologic Soil Group—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties (905 Chatfield Road, Aspen, CO) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/5/2018 Page 1 of 443410004341040434108043411204341160434120043412404341280434132043410004341040434108043411204341160434120043412404341280340610340650340690340730340770340810 340610 340650 340690 340730 340770 340810 39° 12' 23'' N 106° 50' 46'' W39° 12' 23'' N106° 50' 36'' W39° 12' 13'' N 106° 50' 46'' W39° 12' 13'' N 106° 50' 36'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 20 40 80 120 Meters Map Scale: 1:1,570 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. Exhibit 4 02/14/2019 MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available 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 8, Oct 10, 2017 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. Hydrologic Soil Group—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties (905 Chatfield Road, Aspen, CO) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/5/2018 Page 2 of 4 02/14/2019 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 84 Morval loam, 1 to 6 percent slopes C 0.8 6.6% 107 Uracca, moist-Mergel complex, 1 to 6 percent slopes, extremely s B 10.6 87.9% 108 Uracca, moist-Mergel complex, 6 to 12 percent slopes, extremely B 0.7 5.5% Totals for Area of Interest 12.1 100.0% Hydrologic Soil Group—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties 905 Chatfield Road, Aspen, CO Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/5/2018 Page 3 of 402/14/2019 Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties 905 Chatfield Road, Aspen, CO Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/5/2018 Page 4 of 402/14/2019 02/14/2019 02/14/2019 HYDROLOGIC COMPUTATIONS 02/14/2019 Project Description 71053Silv Drainage 10-YR Permit-20180821.SPF Project Options CFS Elevation Rational Kirpich Kinematic Wave YES NO Analysis Options Mar 05, 2018 00:00:00 Mar 05, 2018 03:00:00 Mar 05, 2018 00:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 30 seconds Number of Elements Qty 0 4 22 15 5 0 2 0 19 2 17 0 0 0 0 0 0 Rainfall Details 10 year(s) Outlets .......................................................................... Pollutants .............................................................................. Land Uses ............................................................................ Return Period........................................................................ Links...................................................................................... Channels ...................................................................... Pipes ............................................................................ Pumps .......................................................................... Orifices ......................................................................... Weirs ............................................................................ Nodes.................................................................................... Junctions ...................................................................... Outfalls ......................................................................... Flow Diversions ........................................................... Inlets ............................................................................ Storage Nodes ............................................................. Runoff (Dry Weather) Time Step .......................................... Runoff (Wet Weather) Time Step ........................................ Reporting Time Step ............................................................ Routing Time Step ................................................................ Rain Gages ........................................................................... Subbasins.............................................................................. Enable Overflow Ponding at Nodes ...................................... Skip Steady State Analysis Time Periods ............................ Start Analysis On .................................................................. End Analysis On ................................................................... Start Reporting On ................................................................ Antecedent Dry Days ............................................................ File Name ............................................................................. Flow Units ............................................................................. Elevation Type ...................................................................... Hydrology Method ................................................................. Time of Concentration (TOC) Method .................................. Link Routing Method ............................................................. 02/14/2019 Subbasin Summary SN Subbasin Area Weighted Average Flow Total Total Total Peak Time of ID Runoff Slope Length Rainfall Runoff Runoff Runoff Concentration Coefficient Volume (ft²)(%)(ft)(in)(in)(ac-in)(cfs)(days hh:mm:ss) 1 Sub-Ex01 11899.98 0.1500 9.3000 213.00 0.31 0.05 0.01 0.15 0 00:05:00 2 Sub-Ex02 4299.98 0.1500 15.2000 147.00 0.31 0.05 0.00 0.06 0 00:05:00 3 Sub-Pr01 13600.00 0.3900 8.5000 163.00 0.31 0.12 0.04 0.45 0 00:05:00 4 Sub-Pr02 3500.00 0.3300 12.0000 111.00 0.31 0.10 0.01 0.10 0 00:05:00 02/14/2019 Subbasin Hydrology Subbasin : Sub-Ex01 Input Data Area (ft²) .......................................................11899.98 Weighted Runoff Coefficient ........................0.1500 Average Slope (%) .......................................9.3000 Flow Length (ft) ............................................213.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -11899.98 B 0.15 Composite Area & Weighted Runoff Coeff.11899.98 0.15 Time of Concentration TOC Method : Kirpich Sheet Flow Equation : Tc = (0.0078 * ((Lf^0.77) * (Sf^-0.385))) Where : Tc = Time of Concentration (min) Lf = Flow Length (ft) Sf = Slope (ft/ft) Flow Length (ft) ............................................213.00 Slope (%) ......................................................9.3 Computed TOC (min) ...................................1.21 Subbasin Runoff Results Total Rainfall (in) ..........................................0.31 Total Runoff (in) ............................................0.05 Peak Runoff (cfs) .........................................0.15 Rainfall Intensity ...........................................3.720 Weighted Runoff Coefficient ........................0.1500 Time of Concentration (days hh:mm:ss) ......0 00:01:13 02/14/2019 Subbasin : Sub-Ex01 02/14/2019 Subbasin : Sub-Ex02 Input Data Area (ft²) .......................................................4299.98 Weighted Runoff Coefficient ........................0.1500 Average Slope (%) .......................................15.2000 Flow Length (ft) ............................................147.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -4299.98 B 0.15 Composite Area & Weighted Runoff Coeff.4299.98 0.15 Time of Concentration Flow Length (ft) ............................................147.00 Slope (%) ......................................................15.2 Computed TOC (min) ...................................0.75 Subbasin Runoff Results Total Rainfall (in) ..........................................0.31 Total Runoff (in) ............................................0.05 Peak Runoff (cfs) .........................................0.06 Rainfall Intensity ...........................................3.720 Weighted Runoff Coefficient ........................0.1500 Time of Concentration (days hh:mm:ss) ......0 00:00:45 02/14/2019 Subbasin : Sub-Ex02 02/14/2019 Subbasin : Sub-Pr01 Input Data Area (ft²) .......................................................13600.00 Weighted Runoff Coefficient ........................0.3900 Average Slope (%) .......................................8.5000 Flow Length (ft) ............................................163.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -13600.00 B 0.39 Composite Area & Weighted Runoff Coeff.13600.00 0.39 Time of Concentration Flow Length (ft) ............................................163.00 Slope (%) ......................................................8.5 Computed TOC (min) ...................................1.02 Subbasin Runoff Results Total Rainfall (in) ..........................................0.31 Total Runoff (in) ............................................0.12 Peak Runoff (cfs) .........................................0.45 Rainfall Intensity ...........................................3.720 Weighted Runoff Coefficient ........................0.3900 Time of Concentration (days hh:mm:ss) ......0 00:01:01 02/14/2019 Subbasin : Sub-Pr01 02/14/2019 Subbasin : Sub-Pr02 Input Data Area (ft²) .......................................................3500.00 Weighted Runoff Coefficient ........................0.3300 Average Slope (%) .......................................12.0000 Flow Length (ft) ............................................111.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -3500.00 B 0.33 Composite Area & Weighted Runoff Coeff.3500.00 0.33 Time of Concentration Flow Length (ft) ............................................111.00 Slope (%) ......................................................12 Computed TOC (min) ...................................0.66 Subbasin Runoff Results Total Rainfall (in) ..........................................0.31 Total Runoff (in) ............................................0.10 Peak Runoff (cfs) .........................................0.10 Rainfall Intensity ...........................................3.720 Weighted Runoff Coefficient ........................0.3300 Time of Concentration (days hh:mm:ss) ......0 00:00:40 02/14/2019 Subbasin : Sub-Pr02 02/14/2019 Junction Results SN Element Peak Peak Max HGL Max HGL Max Min Average HGL Average HGL Time of Time of Total Total Time ID Inflow Lateral Elevation Depth Surcharge Freeboard Elevation Depth Max HGL Peak Flooded Flooded Inflow Attained Attained Depth Attained Attained Attained Occurrence Flooding Volume Attained Occurrence (cfs)(cfs)(ft)(ft)(ft)(ft)(ft)(ft)(days hh:mm)(days hh:mm)(ac-in)(min) 1 S1 0.45 0.45 7825.07 0.27 0.00 3.23 7824.81 0.01 0 00:05 0 00:00 0.00 0.00 2 S12 0.44 0.00 7823.07 0.33 0.00 0.43 7822.76 0.02 0 00:05 0 00:00 0.00 0.00 3 S14 0.00 0.00 7823.08 0.00 0.00 3.55 7823.08 0.00 0 00:00 0 00:00 0.00 0.00 4 S2 0.45 0.00 7824.82 0.27 0.00 3.76 7824.72 0.17 0 00:05 0 00:00 0.00 0.00 5 S2-R1 0.00 0.00 7824.88 0.00 0.00 3.30 7824.88 0.00 0 00:00 0 00:00 0.00 0.00 6 S3 0.45 0.00 7824.53 0.27 0.00 3.39 7824.27 0.01 0 00:05 0 00:00 0.00 0.00 7 S4 0.45 0.00 7824.39 0.27 0.00 5.19 7824.13 0.01 0 00:05 0 00:00 0.00 0.00 8 S5 0.45 0.00 7824.14 0.27 0.00 0.48 7823.88 0.01 0 00:05 0 00:00 0.00 0.00 9 S6 0.45 0.00 7824.05 0.27 0.00 4.33 7823.79 0.01 0 00:05 0 00:00 0.00 0.00 10 S7 0.44 0.00 7823.92 0.27 0.00 0.48 7823.66 0.01 0 00:05 0 00:00 0.00 0.00 11 S8 0.44 0.00 7823.82 0.33 0.00 0.42 7823.82 0.33 0 00:00 0 00:00 0.00 0.00 12 S8-L1 0.00 0.00 7824.85 0.00 0.00 3.65 7824.85 0.00 0 00:00 0 00:00 0.00 0.00 13 S8-L2 0.00 0.00 7824.68 0.00 0.00 3.32 7824.68 0.00 0 00:00 0 00:00 0.00 0.00 14 S8-L3 0.00 0.00 7824.35 0.00 0.00 3.65 7824.35 0.00 0 00:00 0 00:00 0.00 0.00 15 S9 0.44 0.00 7823.27 0.24 0.00 0.51 7823.04 0.01 0 00:05 0 00:00 0.00 0.00 02/14/2019 Pipe Results SN Element Peak Time of Design Flow Peak Flow/Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs)(days hh:mm)(cfs)(ft/sec)(min)(ft)(min) 1 P1 0.45 0 00:05 1.32 0.34 3.91 0.11 0.27 0.40 0.00 Calculated 2 P10 0.44 0 00:05 1.60 0.28 3.93 0.04 0.24 0.36 0.00 Calculated 3 P11 0.44 0 00:05 1.60 0.28 3.92 0.02 0.24 0.36 0.00 Calculated 4 P12 0.44 0 00:05 0.93 0.48 2.63 0.06 0.32 0.49 0.00 Calculated 5 P13 0.00 0 00:00 1.31 0.00 0.00 0.00 0.00 0.00 Calculated 6 P2 0.45 0 00:05 1.30 0.34 3.40 0.14 0.27 0.40 0.00 Calculated 7 P2-R1 0.00 0 00:00 0.86 0.00 0.00 0.00 0.00 0.00 Calculated 8 P3 0.45 0 00:05 1.30 0.34 3.39 0.07 0.27 0.40 0.00 Calculated 9 P4 0.45 0 00:05 1.33 0.34 3.43 0.12 0.27 0.40 0.00 Calculated 10 P5 0.45 0 00:05 1.27 0.35 3.32 0.05 0.27 0.41 0.00 Calculated 11 P6 0.44 0 00:05 1.31 0.34 3.40 0.06 0.27 0.40 0.00 Calculated 12 P7 0.44 0 00:05 1.30 0.34 3.38 0.08 0.27 0.40 0.00 Calculated 13 P8 0.44 0 00:05 1.95 0.23 4.53 0.08 0.22 0.32 0.00 Calculated 14 P8-L1 0.00 0 00:00 0.29 0.00 0.00 0.00 0.00 0.00 Calculated 15 P8-L2 0.00 0 00:00 0.29 0.00 0.00 0.00 0.00 0.00 Calculated 16 P8-L3 0.00 0 00:00 0.29 0.00 0.00 0.00 0.00 0.00 Calculated 17 P9 0.44 0 00:05 1.60 0.28 3.93 0.02 0.24 0.36 0.00 Calculated 02/14/2019 Project Description 71053Silv Drainage 100-YR Permit-20180821.SPF Project Options CFS Elevation Rational Kirpich Kinematic Wave YES NO Analysis Options Mar 05, 2018 00:00:00 Mar 05, 2018 03:00:00 Mar 05, 2018 00:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 30 seconds Number of Elements Qty 0 4 22 15 5 0 2 0 19 2 17 0 0 0 0 0 0 Rainfall Details 100 year(s) Outlets .......................................................................... Pollutants .............................................................................. Land Uses ............................................................................ Return Period........................................................................ Links...................................................................................... Channels ...................................................................... Pipes ............................................................................ Pumps .......................................................................... Orifices ......................................................................... Weirs ............................................................................ Nodes.................................................................................... Junctions ...................................................................... Outfalls ......................................................................... Flow Diversions ........................................................... Inlets ............................................................................ Storage Nodes ............................................................. Runoff (Dry Weather) Time Step .......................................... Runoff (Wet Weather) Time Step ........................................ Reporting Time Step ............................................................ Routing Time Step ................................................................ Rain Gages ........................................................................... Subbasins.............................................................................. Enable Overflow Ponding at Nodes ...................................... Skip Steady State Analysis Time Periods ............................ Start Analysis On .................................................................. End Analysis On ................................................................... Start Reporting On ................................................................ Antecedent Dry Days ............................................................ File Name ............................................................................. Flow Units ............................................................................. Elevation Type ...................................................................... Hydrology Method ................................................................. Time of Concentration (TOC) Method .................................. Link Routing Method ............................................................. 02/14/2019 Subbasin Summary SN Subbasin Area Weighted Average Flow Total Total Total Peak Time of ID Runoff Slope Length Rainfall Runoff Runoff Runoff Concentration Coefficient Volume (ft²)(%)(ft)(in)(in)(ac-in)(cfs)(days hh:mm:ss) 1 Sub-Ex01 11899.98 0.3500 9.3000 213.00 0.53 0.18 0.05 0.60 0 00:05:00 2 Sub-Ex02 4299.98 0.3500 15.2000 147.00 0.53 0.18 0.02 0.22 0 00:05:00 3 Sub-Pr01 13600.00 0.5100 8.5000 163.00 0.53 0.27 0.08 1.01 0 00:05:00 4 Sub-Pr02 3500.00 0.4900 12.0000 111.00 0.53 0.26 0.02 0.25 0 00:05:00 02/14/2019 Subbasin Hydrology Subbasin : Sub-Ex01 Input Data Area (ft²) .......................................................11899.98 Weighted Runoff Coefficient ........................0.3500 Average Slope (%) .......................................9.3000 Flow Length (ft) ............................................213.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -11899.98 B 0.35 Composite Area & Weighted Runoff Coeff.11899.98 0.35 Time of Concentration TOC Method : Kirpich Sheet Flow Equation : Tc = (0.0078 * ((Lf^0.77) * (Sf^-0.385))) Where : Tc = Time of Concentration (min) Lf = Flow Length (ft) Sf = Slope (ft/ft) Flow Length (ft) ............................................213.00 Slope (%) ......................................................9.3 Computed TOC (min) ...................................1.21 Subbasin Runoff Results Total Rainfall (in) ..........................................0.53 Total Runoff (in) ............................................0.18 Peak Runoff (cfs) .........................................0.60 Rainfall Intensity ...........................................6.320 Weighted Runoff Coefficient ........................0.3500 Time of Concentration (days hh:mm:ss) ......0 00:01:13 02/14/2019 Subbasin : Sub-Ex01 02/14/2019 Subbasin : Sub-Ex02 Input Data Area (ft²) .......................................................4299.98 Weighted Runoff Coefficient ........................0.3500 Average Slope (%) .......................................15.2000 Flow Length (ft) ............................................147.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -4299.98 B 0.35 Composite Area & Weighted Runoff Coeff.4299.98 0.35 Time of Concentration Flow Length (ft) ............................................147.00 Slope (%) ......................................................15.2 Computed TOC (min) ...................................0.75 Subbasin Runoff Results Total Rainfall (in) ..........................................0.53 Total Runoff (in) ............................................0.18 Peak Runoff (cfs) .........................................0.22 Rainfall Intensity ...........................................6.320 Weighted Runoff Coefficient ........................0.3500 Time of Concentration (days hh:mm:ss) ......0 00:00:45 02/14/2019 Subbasin : Sub-Ex02 02/14/2019 Subbasin : Sub-Pr01 Input Data Area (ft²) .......................................................13600.00 Weighted Runoff Coefficient ........................0.5100 Average Slope (%) .......................................8.5000 Flow Length (ft) ............................................163.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -13600.00 B 0.51 Composite Area & Weighted Runoff Coeff.13600.00 0.51 Time of Concentration Flow Length (ft) ............................................163.00 Slope (%) ......................................................8.5 Computed TOC (min) ...................................1.02 Subbasin Runoff Results Total Rainfall (in) ..........................................0.53 Total Runoff (in) ............................................0.27 Peak Runoff (cfs) .........................................1.01 Rainfall Intensity ...........................................6.320 Weighted Runoff Coefficient ........................0.5100 Time of Concentration (days hh:mm:ss) ......0 00:01:01 02/14/2019 Subbasin : Sub-Pr01 02/14/2019 Subbasin : Sub-Pr02 Input Data Area (ft²) .......................................................3500.00 Weighted Runoff Coefficient ........................0.4900 Average Slope (%) .......................................12.0000 Flow Length (ft) ............................................111.00 Runoff Coefficient Area Soil Runoff Soil/Surface Description (ft²)Group Coeff. -3500.00 B 0.49 Composite Area & Weighted Runoff Coeff.3500.00 0.49 Time of Concentration Flow Length (ft) ............................................111.00 Slope (%) ......................................................12 Computed TOC (min) ...................................0.66 Subbasin Runoff Results Total Rainfall (in) ..........................................0.53 Total Runoff (in) ............................................0.26 Peak Runoff (cfs) .........................................0.25 Rainfall Intensity ...........................................6.320 Weighted Runoff Coefficient ........................0.4900 Time of Concentration (days hh:mm:ss) ......0 00:00:40 02/14/2019 Subbasin : Sub-Pr02 02/14/2019 Junction Results SN Element Peak Peak Max HGL Max HGL Max Min Average HGL Average HGL Time of Time of Total Total Time ID Inflow Lateral Elevation Depth Surcharge Freeboard Elevation Depth Max HGL Peak Flooded Flooded Inflow Attained Attained Depth Attained Attained Attained Occurrence Flooding Volume Attained Occurrence (cfs)(cfs)(ft)(ft)(ft)(ft)(ft)(ft)(days hh:mm)(days hh:mm)(ac-in)(min) 1 S1 1.01 1.01 7825.24 0.44 0.00 3.06 7824.82 0.02 0 00:05 0 00:00 0.00 0.00 2 S12 0.99 0.00 7823.50 0.76 0.00 0.00 7822.77 0.03 0 00:05 0 00:05 0.00 1.00 3 S14 0.00 0.00 7823.08 0.00 0.00 3.55 7823.08 0.00 0 00:00 0 00:00 0.00 0.00 4 S2 1.00 0.00 7824.99 0.44 0.00 3.59 7824.73 0.18 0 00:05 0 00:00 0.00 0.00 5 S2-R1 0.00 0.00 7824.88 0.00 0.00 3.30 7824.88 0.00 0 00:00 0 00:00 0.00 0.00 6 S3 1.00 0.00 7824.70 0.44 0.00 3.22 7824.28 0.02 0 00:05 0 00:00 0.00 0.00 7 S4 1.00 0.00 7824.56 0.44 0.00 5.03 7824.14 0.02 0 00:05 0 00:00 0.00 0.00 8 S5 0.99 0.00 7824.31 0.44 0.00 0.31 7823.89 0.02 0 00:05 0 00:00 0.00 0.00 9 S6 0.99 0.00 7824.22 0.44 0.00 4.16 7823.80 0.02 0 00:05 0 00:00 0.00 0.00 10 S7 0.99 0.00 7824.09 0.44 0.00 0.31 7823.67 0.02 0 00:05 0 00:00 0.00 0.00 11 S8 0.99 0.00 7823.93 0.44 0.00 0.31 7823.82 0.33 0 00:05 0 00:00 0.00 0.00 12 S8-L1 0.00 0.00 7824.85 0.00 0.00 3.65 7824.85 0.00 0 00:00 0 00:00 0.00 0.00 13 S8-L2 0.00 0.00 7824.68 0.00 0.00 3.32 7824.68 0.00 0 00:00 0 00:00 0.00 0.00 14 S8-L3 0.00 0.00 7824.35 0.00 0.00 3.65 7824.35 0.00 0 00:00 0 00:00 0.00 0.00 15 S9 0.99 0.00 7823.41 0.38 0.00 0.37 7823.04 0.01 0 00:05 0 00:00 0.00 0.00 02/14/2019 Pipe Results SN Element Peak Time of Design Flow Peak Flow/Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs)(days hh:mm)(cfs)(ft/sec)(min)(ft)(min) 1 P1 1.00 0 00:05 1.32 0.76 4.75 0.09 0.43 0.65 0.00 Calculated 2 P10 0.99 0 00:05 1.60 0.62 4.84 0.03 0.38 0.57 0.00 Calculated 3 P11 0.99 0 00:05 1.60 0.62 4.83 0.02 0.38 0.57 0.00 Calculated 4 P12 0.99 0 00:06 0.93 1.07 3.10 0.05 0.62 0.93 0.00 > CAPACITY 5 P13 0.00 0 00:00 1.31 0.00 0.00 0.00 0.00 0.00 Calculated 6 P2 1.00 0 00:05 1.30 0.77 4.13 0.12 0.44 0.66 0.00 Calculated 7 P2-R1 0.00 0 00:00 0.86 0.00 0.00 0.00 0.00 0.00 Calculated 8 P3 1.00 0 00:05 1.30 0.76 4.12 0.06 0.44 0.65 0.00 Calculated 9 P4 0.99 0 00:05 1.33 0.75 4.18 0.10 0.43 0.65 0.00 Calculated 10 P5 0.99 0 00:05 1.27 0.78 4.03 0.04 0.44 0.67 0.00 Calculated 11 P6 0.99 0 00:05 1.31 0.76 4.14 0.05 0.43 0.65 0.00 Calculated 12 P7 0.99 0 00:05 1.30 0.77 4.10 0.07 0.44 0.66 0.00 Calculated 13 P8 0.99 0 00:05 1.95 0.51 5.61 0.06 0.34 0.51 0.00 Calculated 14 P8-L1 0.00 0 00:00 0.29 0.00 0.00 0.00 0.00 0.00 Calculated 15 P8-L2 0.00 0 00:00 0.29 0.00 0.00 0.00 0.00 0.00 Calculated 16 P8-L3 0.00 0 00:00 0.29 0.00 0.00 0.00 0.00 0.00 Calculated 17 P9 0.99 0 00:05 1.60 0.62 4.83 0.02 0.38 0.57 0.00 Calculated 02/14/2019 HYDRAULIC COMPUTATIONS 02/14/2019 DETENTION VOLUME CALCULATIONS 02/14/2019 Basin PR-01 South 100-Year Detention Volume Calculations Element ID Out-Ex0 1S Out-Pr0 1S Maximum Total Inflow (cfs) 0.60 1.01 Minimum Total Inflow (cfs) 0.00 0.00 Event Mean Total Inflow (cfs) 0.02 0.03 Duration of Exceedances (hrs) N/A N/A Duration of Deficits (hrs) N/A N/A Number of Exceedances N/A N/A Number of Deficits N/A N/A Volume of Exceedance (ft³) N/A N/A Volume of Deficit (ft³) N/A N/A Total Inflow Volume (ft³) 181.29 301.9 Detention Storage (ft³) N/A 124.90 Exceedance 0 Deficit 0 02/14/2019 Basin PR-02 North 100-Year Detention Volume Calculations Element ID Out-Ex0 1N Out-Pr0 1N Maximum Total Inflow (cfs) 0.22 0.25 Minimum Total Inflow (cfs) 0.00 0.00 Event Mean Total Inflow (cfs) 0.01 0.01 Duration of Exceedances (hrs) N/A N/A Duration of Deficits (hrs) N/A N/A Number of Exceedances N/A N/A Number of Deficits N/A N/A Volume of Exceedance (ft³) N/A N/A Volume of Deficit (ft³) N/A N/A Total Inflow Volume (ft³) 65.51 74.65 Detention Storage (ft³) N/A 11.65 Exceedance 0 Deficit 0 02/14/2019 10-Year Detention Volume Calculations Element ID Out-Ex 01 Out-Pr 01 Maximum Total Inflow (cfs) 0.21 0.55 Minimum Total Inflow (cfs) 0.00 0.00 Event Mean Total Inflow (cfs) 0.01 0.02 Duration of Exceedances (hrs) N/A N/A Duration of Deficits (hrs) N/A N/A Number of Exceedances N/A N/A Number of Deficits N/A N/A Volume of Exceedance (ft³) N/A N/A Volume of Deficit (ft³) N/A N/A Total Inflow Volume (ft³) 62.26 165.4 8 Detention Storage (ft³) N/A 105.4 8 Exceedance 0 Deficit 0 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019 Weir Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Sunday, Aug 12 2018 Bioretention Pond A Rectangular Weir Crest = Broad Bottom Length (ft) = 2.00 Total Depth (ft) = 0.25 Calculations Weir Coeff. Cw = 2.60 Compute by: Known Q Known Q (cfs) = 0.25 Highlighted Depth (ft) = 0.13 Q (cfs) = 0.250 Area (sqft) = 0.26 Velocity (ft/s) = 0.95 Top Width (ft) = 2.00 0 .5 1 1.5 2 2.5 3 Depth (ft)Depth (ft)Bioretention Pond A -0.50 -0.50 0.00 0.00 0.50 0.50 1.00 1.00 Length (ft)Weir W.S.02/14/2019 Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Monday, Sep 24 2018 Vault Outlets (2) 8 Inch Pipes to Level Spreader Invert Elev Dn (ft) = 7823.22 Pipe Length (ft) = 10.00 Slope (%) = 0.50 Invert Elev Up (ft) = 7823.27 Rise (in) = 8.0 Shape = Circular Span (in) = 8.0 No. Barrels = 2 n-Value = 0.012 Culvert Type = Circular Culvert Culvert Entrance = Smooth tapered inlet throat Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 Embankment Top Elevation (ft) = 7825.00 Top Width (ft) = 8.00 Crest Width (ft) = 20.00 Calculations Qmin (cfs) = 0.50 Qmax (cfs) = 1.20 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 1.05 Qpipe (cfs) = 1.05 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 1.86 Veloc Up (ft/s) = 2.94 HGL Dn (ft) = 7823.72 HGL Up (ft) = 7823.61 Hw Elev (ft) = 7823.77 Hw/D (ft) = 0.75 Flow Regime = Inlet Control 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Drainage Swale A 10-Year Triangular Side Slopes (z:1) = 17.00, 17.00 Total Depth (ft) = 0.25 Invert Elev (ft) = 7824.75 Slope (%) = 9.80 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.45 Highlighted Depth (ft) = 0.11 Q (cfs) = 0.450 Area (sqft) = 0.21 Velocity (ft/s) = 2.19 Wetted Perim (ft) = 3.75 Crit Depth, Yc (ft) = 0.14 Top Width (ft) = 3.74 EGL (ft) = 0.18 0 1 2 3 4 5 6 7 8 9 10 11 Elev (ft)Depth (ft)Section 7824.00 -0.75 7824.50 -0.25 7825.00 0.25 7825.50 0.75 7826.00 1.25 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Drainage Swale B 10-Year Triangular Side Slopes (z:1) = 4.00, 4.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 7824.03 Slope (%) = 2.20 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.45 Highlighted Depth (ft) = 0.26 Q (cfs) = 0.450 Area (sqft) = 0.27 Velocity (ft/s) = 1.66 Wetted Perim (ft) = 2.14 Crit Depth, Yc (ft) = 0.24 Top Width (ft) = 2.08 EGL (ft) = 0.30 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Elev (ft)Depth (ft)Section 7823.75 -0.28 7824.00 -0.03 7824.25 0.22 7824.50 0.47 7824.75 0.72 7825.00 0.97 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Drainage Swale C 10-Year Triangular Side Slopes (z:1) = 4.00, 4.00 Total Depth (ft) = 0.75 Invert Elev (ft) = 7820.80 Slope (%) = 13.10 N-Value = 0.035 Calculations Compute by: Known Q Known Q (cfs) = 0.10 Highlighted Depth (ft) = 0.11 Q (cfs) = 0.100 Area (sqft) = 0.05 Velocity (ft/s) = 2.07 Wetted Perim (ft) = 0.91 Crit Depth, Yc (ft) = 0.14 Top Width (ft) = 0.88 EGL (ft) = 0.18 0 1 2 3 4 5 6 7 8 Elev (ft)Depth (ft)Section 7820.00 -0.80 7820.50 -0.30 7821.00 0.20 7821.50 0.70 7822.00 1.20 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Trench Drain 10-Year Rectangular Bottom Width (ft) = 0.58 Total Depth (ft) = 1.30 Invert Elev (ft) = 7827.62 Slope (%) = 0.50 N-Value = 0.015 Calculations Compute by: Q vs Depth No. Increments = 30 Highlighted Depth (ft) = 0.39 Q (cfs) = 0.479 Area (sqft) = 0.23 Velocity (ft/s) = 2.12 Wetted Perim (ft) = 1.36 Crit Depth, Yc (ft) = 0.28 Top Width (ft) = 0.58 EGL (ft) = 0.46 0 .25 .5 .75 1 1.25 Elev (ft)Depth (ft)Section 7827.00 -0.62 7827.50 -0.12 7828.00 0.38 7828.50 0.88 7829.00 1.38 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Drainage Swale A 100-Year Triangular Side Slopes (z:1) = 17.00, 17.00 Total Depth (ft) = 0.25 Invert Elev (ft) = 7824.75 Slope (%) = 9.80 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 1.01 Highlighted Depth (ft) = 0.15 Q (cfs) = 1.010 Area (sqft) = 0.38 Velocity (ft/s) = 2.64 Wetted Perim (ft) = 5.11 Crit Depth, Yc (ft) = 0.19 Top Width (ft) = 5.10 EGL (ft) = 0.26 0 1 2 3 4 5 6 7 8 9 10 11 Elev (ft)Depth (ft)Section 7824.00 -0.75 7824.50 -0.25 7825.00 0.25 7825.50 0.75 7826.00 1.25 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Drainage Swale B 100-Year Triangular Side Slopes (z:1) = 4.00, 4.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 7824.03 Slope (%) = 2.20 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 1.01 Highlighted Depth (ft) = 0.34 Q (cfs) = 1.010 Area (sqft) = 0.46 Velocity (ft/s) = 2.18 Wetted Perim (ft) = 2.80 Crit Depth, Yc (ft) = 0.34 Top Width (ft) = 2.72 EGL (ft) = 0.41 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Elev (ft)Depth (ft)Section 7823.75 -0.28 7824.00 -0.03 7824.25 0.22 7824.50 0.47 7824.75 0.72 7825.00 0.97 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Aug 21 2018 Drainage Swale C 100-Year Triangular Side Slopes (z:1) = 4.00, 4.00 Total Depth (ft) = 0.75 Invert Elev (ft) = 7820.80 Slope (%) = 13.10 N-Value = 0.035 Calculations Compute by: Known Q Known Q (cfs) = 0.25 Highlighted Depth (ft) = 0.16 Q (cfs) = 0.250 Area (sqft) = 0.10 Velocity (ft/s) = 2.44 Wetted Perim (ft) = 1.32 Crit Depth, Yc (ft) = 0.19 Top Width (ft) = 1.28 EGL (ft) = 0.25 0 1 2 3 4 5 6 7 8 Elev (ft)Depth (ft)Section 7820.00 -0.80 7820.50 -0.30 7821.00 0.20 7821.50 0.70 7822.00 1.20 Reach (ft) 02/14/2019 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, May 16 2018 Trench Drain 100-Year Rectangular Bottom Width (ft) = 0.58 Total Depth (ft) = 1.30 Invert Elev (ft) = 7827.62 Slope (%) = 0.50 N-Value = 0.015 Calculations Compute by: Q vs Depth No. Increments = 30 Highlighted Depth (ft) = 0.74 Q (cfs) = 1.050 Area (sqft) = 0.43 Velocity (ft/s) = 2.46 Wetted Perim (ft) = 2.05 Crit Depth, Yc (ft) = 0.47 Top Width (ft) = 0.58 EGL (ft) = 0.83 0 .25 .5 .75 1 1.25 Elev (ft)Depth (ft)Section 7827.00 -0.62 7827.50 -0.12 7828.00 0.38 7828.50 0.88 7829.00 1.38 Reach (ft) 02/14/2019 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10Capacity (cfs)Head (ft) Nyloplast 12" Standard Grate Inlet Capacity Chart 02/14/2019 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10Capacity (cfs)Head (ft) Nyloplast 12" Drop In Grate Inlet Capacity Chart 02/14/2019 Inlet Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Aug 21 2018 100-Yr 6-Inch Area Drain Capacity Calculation, 25% Open Area Drop Grate Inlet Location = Sag Curb Length (ft) = -0- Throat Height (in) = -0- Grate Area (sqft) = 0.06 Grate Width (ft) = 0.50 Grate Length (ft) = 0.50 Gutter Slope, Sw (ft/ft) = 0.020 Slope, Sx (ft/ft) = 0.020 Local Depr (in) = -0- Gutter Width (ft) = 0.50 Gutter Slope (%) = -0- Gutter n-value = -0- Calculations Compute by: Known Q Q (cfs) = 0.08 Highlighted Q Total (cfs) = 0.08 Q Capt (cfs) = 0.08 Q Bypass (cfs) = -0- Depth at Inlet (in) = 0.74 Efficiency (%) = 100 Gutter Spread (ft) = 6.66 Gutter Vel (ft/s) = -0- Bypass Spread (ft) = -0- Bypass Depth (in) = -0- 02/14/2019 Inlet Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Aug 21 2018 100-Yr 4-Inch Area Drain Capacity Calculation, 25% Open Area Drop Grate Inlet Location = Sag Curb Length (ft) = -0- Throat Height (in) = -0- Grate Area (sqft) = 0.03 Grate Width (ft) = 0.33 Grate Length (ft) = 0.33 Gutter Slope, Sw (ft/ft) = 0.020 Slope, Sx (ft/ft) = 0.020 Local Depr (in) = -0- Gutter Width (ft) = 0.33 Gutter Slope (%) = -0- Gutter n-value = -0- Calculations Compute by: Known Q Q (cfs) = 0.08 Highlighted Q Total (cfs) = 0.08 Q Capt (cfs) = 0.08 Q Bypass (cfs) = -0- Depth at Inlet (in) = 2.96 Efficiency (%) = 100 Gutter Spread (ft) = 24.96 Gutter Vel (ft/s) = -0- Bypass Spread (ft) = -0- Bypass Depth (in) = -0- 02/14/2019 02/14/2019 02/14/2019 02/14/2019 02/14/2019