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HomeMy WebLinkAboutFile Documents.108 Midland Ave.0264.2017 (6).ARBK 108 Midland Avenue,Aspen, Colorado July 21,2017 Drainage Report for Sandler Residence 108 Midland Avenue Aspen, Colorado Submitted To: City of Aspen Engineering Department 517 E. Hopkins St. Aspen, CO 81611 Prepared by: Sopris Engineering, LLC 502 Main Street Suite A3 Carbondale, Colorado 81623 • Po° ,mac o 28377 ` '.01121I1kZ1 SE Project Number: 17010 July 21, 2017 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21, 2017 Table of Contents A. Purpose of Report 2 B. Project Location, Background & Overview 2 C. Existing Site Description 2 D. Historic Drainage Basin Description 4 E. Post Drainage Basin & Sub-basin Descriptions 4 F. Hydrologic Methods and Assumptions 6 G. Hydraulic Methods and Assumptions 8 H. Water Quality Treatment 10 I. Stormwater Detention 12 J. Low Impact Design 13 K. Maintenance Plan 14 L. Sediment and Erosion Control/BMPs 15 M. Conclusions 16 N. References 16 O. Engineer's Statement of Design Compliance 17 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 A. Purpose of Report Based on the location of this project and the proposed activity, the purposes of this Drainage Report are to: • Comply with the City of Aspen's Urban Runoff Management Plan (URMP) for a "Major Design" • Estimate post development peak runoff rates for sizing of stormwater infrastructure • Reduce developed peak discharge rates from the property to historic levels • Determine the required water quality treatment volumes for proposed impervious areas • Promote the City of Aspen's 9 Principles to managing stormwater runoff • Illustrate that the proposed improvements will have no adverse impact to drainage on-site or downstream of the site B. Project Location, Background & Overview The subject property is defined as Lot 1 of the Ferguson Exemption Subdivision located at 108 Midland Avenue within the City of Aspen, Colorado. According to the City's zone district mapping the property lies within the PD zone district, R-14A. The property currently consists of a 2-story single family residence with a walkout basement facing the north side of the property. The structure was constructed in 1984 according to the Pitkin County Assessor's site. An existing pond primarily constructed on the adjacent property (Lot 2) encroaches upon the eastern edge of the subject property (Lot 1). The anticipated scopes of work for the proposed improvements to the property include the following: • Demolition of the existing residence to facilitate the construction of a new single family residence with a gross floor area of 7,340 sf • Resurfacing the existing driveway to provide snowmelted concrete • Reconstruction of the existing driveway where necessary to match required finished floor elevation • New exterior terraced patios and site walls • New exterior condenser and utility meter pad • Removal of pond encroachment As noted above, a small portion of an existing pond encroaches onto the east side of the property (Lot 1) though the majority of the pond is constructed on the adjacent parcel (Lot 2). According to the project's lawyer, Lot 1 has "perpetual and exclusive right to access, use and enjoyment of the pond, as well as the water rights related thereto...". Lot 2 is "only granted a license/right to use the pond". It is our understanding that the two lot owners have mutually agreed to vacate the existing pond and that Lot 2 is in the process of submitting a development application to convert the pond to a pass through stream/water feature. C. Existing Site Description The subject property currently encompasses an existing two story single family home with a walkout basement, paved access driveway (south side) and historic gravel access (nort k. C IVE D 21P0a/-1e6/2 017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 portion of an existing pond encroaches onto the eastern property line of the subject property. The ownership and pond usage rights are spelled out in an agreement with the adjacent property (139 Robinson Road). It is our understanding both properties wish to vacate the existing pond and vacate the shared agreement. It is also our understanding that a development application reflecting the pond abandonment is currently being prepared by 139 Robinson Road. Site topography generally slopes from the east to the west toward Midland Avenue. The southern portion of the site drains down a steep existing driveway toward the intersection of Midland Avenue and State Highway 82. A steep existing hillside separates the subject property from Midland Avenue roadway platform to the west. The northern portion of the site drains west, down an existing gravel access drive and onto Midland Avenue. This existing gravel drive will be reclaimed and landscaped as part of this development submittal. Various roof drain gutter downspouts were observed on the existing structure with two primary outlet locations found. The first downspout location observed directs stormwater to the steep hillside on the west side of the subject property. The second roof drain outlet location was found to outlet to a rip rap lined channel on the north edge of the property. This channel leads directly to Snyder Park to the north of the subject property. The upper reaches of Midland Avenue appear to drain down an existing access trail to Snyder Park via an existing curb cut. As such this project assumes that all existing surface runoff is routed to Snyder Park via a direct connection or through delayed surface runoff via Midland Avenue curb and gutter. A percolation test has been performed in support of this report and the underlying soils are considered to be Type C classification according to the NRCS Soil Map for the City of Aspen within the URMP. However the geotechnical boring log depicts free draining material at an approximate elevation of 7958. The project's intent would be to install any proposed drywells to the depths of the free draining soils that have been field tested with an approximate infiltration rate of 120 in/hr. A conservative infiltration rate of 5 in/hr infiltration rate was utilized in preparation of this report. The subject property falls outside of the limits studied within the Surface Drainage Master Plan for the City of Aspen, dated November 2001 prepared by WRC Engineering, Inc. and is not directly connected to the stormwater system within the Highway 82 corridor. According to Section 5 of the URMP, projects not directly connected to the City's stormwater collection system will be required to detain to the historic peak flow rates for the 5- and 100-year storm events and provide water quality treatment for the proposed impervious areas. The property is located in Zone X on FEMA Flood Insurance Rate Map panel number 08097CO204C with effective date of June 4, 1987. FEMA designates Zone X as being an area outside the 0.2% (500 year storm) annual chance floodplain. An access and utility easement that accommodates the existing driveway alignment and a portion of the utility services is located along the south side of the property (Rec. # 22278). An additional 15' Access & Utility easement (Bk.11 Pg. 59) accommodates the lower portion of the existing driveway near the existing curb cut along Midland Avenue. An existing 15' Open Space Easement (Bk. 11 Pg. 59) abuts the southern property line, and a portion of the existing driveway falls within this easement. RECEIVED 310Pa/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 D. Historic Drainage Basin Description A study of the historic and existing drainage patterns in and around the subject property was conducted through site visits and analysis of existing conditions topography provided. After walking the site, it was determined that nearly all existing site runoff is contributory to Snyder Park, which is directly north of the subject parcel. A large portion of the existing site runoff is directly connected to the Snyder Park boundary through an existing 4" cast iron pipe, which daylights to an existing rip rap lined channel connecting to Snyder Park. This cast iron pipe collects the majority of the roof drainage from the existing two story residence. Runoff from the flat roof above the existing garage drains to the steep hillside on the west side of the subject property, across the sidewalk and into the Midland Avenue curb and gutter collection system. After discussions with City Engineering, it was determined to analyze Snyder Park as the developed conditions design discharge location. Given the fact that all existing runoff is contributory to Snyder Park, it was agreed upon to verify that the proposed development will be required to reduce developed peak runoff to historic conditions. The analysis boundary determined by delineating the total contributory area to the proposed drywell and applying a runoff coefficient for completely undeveloped project site (ie. historic conditions). Two primary existing conditions drainage basins were established for this report in order to properly size both detention and water quality treatment facilities. Further discussion of the basin characteristics are discussed below. No offsite basins contributing runoff to the existing development were observed and therefore not defined. HIST1- Basin HIST1 primarily encompasses the contributory drainage area to the proposed drywell located on the north end of the subject property. The basin includes runoff from the entire proposed roof area, the exterior terraced patios and the proposed auto court. The extents of this basin were established to compare peak runoff for the proposed improvements to historic surface treatment. This comparison was utilized to determine the required detention volume for the proposed conditions. HIST2- Basin HIST2 encompasses the contributory drainage area to the proposed drywell located on the southern end of the existing driveway. This basin includes runoff generated from portions of the existing driveway that cannot be physically directed to the proposed water quality and detention drywell located on the north end of the subject property. The extents of this basin were established to compare peak runoff for the proposed improvements to historic surface treatment. This comparison was utilized to determine the required detention volume for the proposed conditions. Section G of this report describes the hydrologic methods and assumptions that were used to estimate the existing peak runoff rates for each of the basins described above. The results of this analysis can be found within Table 1 of Section G. E. Post Drainage Basin & Sub-basin Descriptions The overall drainage mitigation approach for this project includes routing onsite stormwater runoff to a designated water quality treatment/detention area. In order to properly size and design the drainage infrastructure the proposed site was broken into seven on-site post development drainage basins and associated sub-basins. Descriptions of these basins and sub-basins are provided below and building permit civil plans have been provided as an attachment for illustrative support. RECEIVED 4 jF0a e6/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Basin 1: includes onsite area that will be contributing runoff to a dry well (DW-A) located along the north side of the site. This dry well will provide water quality treatment and stormwater detention for the majority of the site improvements. The dry well will be installed within a depressed area and an overflow inlet will be provided to control discharge rates exiting the facility. Discharge flows will be limited to historic rates and routed to an existing channel that currently directs roof runoff from the existing residence to Snyder Park. In support of sizing stormwater infrastructure Basin 1 was divided into several sub-basins as further described below: Basin 1A boundary includes a portion of the impervious snowmelted concrete driveway and adjacent vegetated landscaping. Surface runoff generated within the basin is directed to a proposed on grade trench drain (Inlet Al) perpendicular to the driveway surface. Collected runoff is routed through the west portion of the site and into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 1 B boundary primarily includes the snowmelted concrete autocourt, a portion of the snowmelted concrete driveway as well as adjacent vegetated landscaping. Surface runoff generated within the basin is directed towards a proposed sump trench drain (Inlet B1) integrated within the autocourt surface. Collected runoff is routed through the west portion of the site and into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 1C boundary includes the onsite vegetated landscaping zone south of the proposed garage. Surface runoff generated within the basin is directed to a landscaping inlet behind a proposed site wall (Inlet C1). Collected runoff is routed through the west portion of the site and into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 1D boundary includes the impervious patio that is not above lower level structure roughly adjacent to the exterior spiral staircase. The vegetated landscape buffer on the west portion of the basin is also included within the basin limits. Surface runoff generated within the basin is directed centrally to a trench drain integrated within the patio surface (Inlet D1). Collected runoff is routed through the west portion of the site and into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 1 E boundary includes the impervious patio that is not above lower level and includes the exterior spa and fireplace. The vegetated landscape buffer on the west portion of the basin is also included within the basin limits. Surface runoff generated within the basin is directed centrally to a trench drain integrated within the patio surface (Inlet E1). Collected runoff is routed through the west portion of the site and into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 1 F boundary includes the impervious patio that is not above lower level and includes the exterior water feature and lower tiered terraced. Surface runoff generated within the basin is directed centrally to a sump drain integrated within the patio surface (Inlet F1). Collected runoff is routed through the west portion of the site and into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 1G boundary primarily includes the western elevated roof system as well as the exterior on grade patios that are above the lower level. Surface runoff generated within the basin is collected in various roof drains and routed internally through the structure. Roof drainage is then piped directly into the proposed DW-A for water quality treatment and ultimately into Snyder Park. RECEIVED 51P0a/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Basin 1H boundary primarily includes the eastern elevated roof system. Surface runoff generated within the basin is collected in various roof drains and routed internally through the structure. Roof drainage is then piped directly into the proposed DW-A for water quality treatment and ultimately into Snyder Park. Basin 11 boundary includes the onsite vegetated landscaping zone and exterior paver stairs southeast of the proposed garage. Surface runoff generated within the basin is directed to a sump inlet designed in a low point within the vegetated landscaping (Inlet I1). Collected runoff is routed through the east portion of the site and into the proposed DW-A for water quality treatment, and ultimately into Snyder Park. Basin 1J boundary includes the onsite vegetated landscaping zone east of the proposed residence. Surface runoff generated within the basin is directed to a sump inlet designed in a low point within the vegetated landscaping (Inlet J1). Collected runoff is routed through the east portion of the site and into the proposed DW-A for water quality treatment, and ultimately into Snyder Park. Basin 1 K boundary includes the onsite vegetated landscaping zone and landscape boulder wall east of the proposed residence. Surface runoff generated within the basin is directed to a sump inlet designed in a low point within the vegetated landscaping (Inlet K1). Collected runoff is routed through the east portion of the site and into the proposed DW-A for water quality treatment, and ultimately into Snyder Park. Basin 1L boundary includes the onsite vegetated landscaping swale, exterior site stairs and concrete condenser pad north of the proposed residence. Surface runoff generated within the basin collected within the onsite vegetated swale and routed to the rim associated with DW-A and ultimately into Snyder Park. Basin 2 includes onsite area that will be contributing runoff to a dry well (DW-B) located along the south side of the site. This dry well will provide water quality treatment and stormwater retention for the portion of the existing driveway that cannot be routed through the site to DW-A. The dry well will be installed within a depressed area and an overflow inlet will be provided to control discharge rates exiting the facility. Discharge flows will be retained up to the 100-year storm event. Storm events in excess of the drywell's capacity will bubble up out of the trench drain and continue down its existing drainage route to Snyder Park via Midland Avenue The post development flows for the 5-yr and 100-yr storm events have been estimated and are summarized within Table 2 located in the following section of this report. F. Hydrologic Methods and Assumptions The drainage criteria used for this study was based on the COA's URMP with supplemental information taken from Urban Drainage Flood Control District Manual (UDFCD). The improvements associated with this project classify it as a "Major Design"which requires an analysis for the 5- and 100-year storm events. This section describes the hydrological assumptions and methods used to estimate the peak runoff rates associated with the 5- and 100-year storm events. Building permit drawings have been provided as an attachment for illustrational support of the proposed stormwater conveyance system and overall grading plan. RECEIVED 61P0ae6/2 017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Peak Runoff rates for the 10- and 100-year storm events were calculated using the Rational Hydrologic Method (Eq. 1) since the cumulative total of basin areas was less than 90 acres. Eq. 1: Q = C* I * A Q= Runoff Flow Rate(cfs) C= Runoff Coefficient I = Rainfall Intensity(in/hr) A=Area of Basin (acres) The runoff coefficient (C) is a variable that represents the ratio of runoff to rainfall volumes during a storm event. The determination of C mainly depends on the soil type, watershed impervious and storm event frequency. Each drainage basin was studied to determine the percent of impervious area. Landscaping areas were assumed to be 0% impervious or 0.15 and 0.50 for the 5- and 100- year runoff coefficients, respectively. Roofs, patios and concrete areas were all assumed to be 100% impervious or 0.90 and 0.96 for the 5- and 100-year runoff coefficients, respectively. Areas with impervious areas different from 0% or 100% were entered into UD-Rational Spreadsheets to determine the corresponding 5- and 100-year runoff coefficients. UD-Rational Spreadsheet was developed by Urban Drainage Flood Control District (UDFCD). 5-year runoff coefficients are calculated automatically by the 100-yr UD spreadsheet. The spreadsheets have been provided within Appendix A of this report. The design rainfall duration used in the Rational Method is referred to as the time of concentration. The time of concentration is the cumulative travel time, including overland flow and channelized flow, for runoff to get from the furthest point upstream of a basin to a designated design point. Per COA URMP, 5 minutes was used as the absolute minimum time of concentration. This minimum value was adopted for all post developed drainage basins given the short travel distances. The resultant rainfall intensities were used to estimate the peak runoff rates for each of the basins and sub-basins. A summary of the results for existing and post development conditions are summarized within Tables 1 and 2, respectively. Table 1: 10 & 100-Yr Existing Drainage Basin Peak Runoff Summary BASIN AREA % To Iio Qs BASIN AREA % To Iloo Qioo I.D. (ACRES) IMPERV C5 (mins) (in/hr) (cfs) I.D. (ACRES) IMPERV Cloo (mins) (in/hr) (cfs) HIST1 0.26 0.0% 0.15 7.46 2.51 0.10 HIST1 0.263 0.0% 0.50 7.46 5.38 0.707 HIST2 0.023 0.0% 0.15 5.0 2.98 0.010 HIST2 0.023 0.0% 0.50 5.0 6.32 0.074 Table 2: 10- & 100-Yr Post Improvement Basin Peak Runoff Summary BASIN AREA % To 15 45 BASIN AREA % To hoo Qmo I.D. (ACRES) IMPERV C5 (mins) (in/hr) (cfs) I.D. (ACRES) IMPERV Cioo (mins) (in/hr) (cfs) BASIN IA 0.012 68.0% 0.51 5.0 2.98 0.018 BASIN IA _ 0.012 68.0% 0.66 5.0 6.32 0.049 BASIN 1B 0.051 86.0% 0.69 5.0 2.98 0.105 BASIN 1B 0.051 86.0% 0.79 5.0 6.32 0.255 BASIN 1C 0.006 0.0% 0.15 5.0 2.98 0.003 BASIN 1C 0.006 0.0% 0.50 5.0 _ 6.32 0.020 BASIN 1D 0.008 54.2% 0.42 5.0 2.98 0.010 BASIN 1D 0.008 54.2% 0.61 5.0 6.32 0.032 BASIN 1E 0.018 80.9% 0.64 5.0 2.98 0.034 BASIN 1E 0.018 80.9% 0.75 5.0 6.32 0.085 BASIN 1F 0.009 100.0% 0.90 5.0 2.98 0.025 BASIN 1F _ 0.009 100.0% 0.96 5.0 _ 6.32 0.056 BASIN 1G 0.051 84.3% 0.67 5.0 2.98 0.101 BASIN 1G 0.051 84.3% 0.78 5.0 6.32 0.250 BASIN 1H 0.041 92.7% 0.78 5.0 2.98 0.095 BASIN 1H _ 0.041 92.7% 0.86 5.0 _ 6.32 0.221 BASIN 11 0.003 13.3% 0.23 5.0 2.98 0.002 BASIN 11 0.003 13.3% 0.54 5.0 6.32 0.012 BASIN 11 0.007 4.1% 0.18 5.0 2.98 0.004 BASIN 11 0.007 4.1% 0.51 5.0 6.32 0.022 BASIN 1K 0.010 2.3% 0.17 5.0 2.98 0.005 BASIN 1K _ 0.010 2.3% 0.51 5.0 _ 6.32 0.032 BASIN 1L 0.045 9.7% 0.21 5.0 2.98 0.028 BASIN 1L 0.045 9.7% 0.53 5.0 6.32 0.150 TOTAL AREA= 0.26 TOTALCFS= 0.43 TOTAL AREA= 0.26 TOTALCFS= 1.18 BASIN2 0.023 84.0% 0.67 5.0 2.98 0.05 BASIN2 0.023 84.0% 0.78 5.0 632rs L 0 1 -'41 tr= ' 1 ') TOTAL AREA= 0.023 TOTALCFS= 0.05 TOTAL AREA= 0.023 TOTAL CFS= 0 1 10/-1e6/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Upon review of Tables 1 and 2 site generated runoff to Snyder Park will be decreased to historic runoff rates. G. Hydraulic Methods and Assumptions The post improvement drainage sub-basins described above were analyzed to verify the sizing of the proposed stormwater conveyance systems proposed throughout the site. This section describes the hydraulic methods and assumptions that were used to assist in the sizing of these stormwater infrastructure improvements. The items that were studied include inlets, drainage channel and storm sewer pipes. Supporting calculations are provided within Appendix B of this report. Eq. 3: Q = C*Amin * (2gh)0.5 Eq. 3.1 : Q = C*(0.5)L*h)1.5 Q= 100-year contributing peak flow rate (cfs) Q= Intercepting capacity C=Coefficient of Discharge (0.6) C=Coefficient of Discharge (3.3) Amin= Minimum allowable area(sf) L=Wetted Length of Grate (ft) h =Available head (ft); h=Available Head (ft) g =Acceleration from Gravity(32.2 ft/sec2) Equation 3 restructured to solve for minimum area based on a 50% clogging factor: Eq. 3a: Amin = 2* Q/(C*(2gh)o.5) Sump Inlets have been proposed at various low points within the proposed development. There are also several sump drains proposed above the subsurface lower level or are required to be routed through the structure. In this case, the drains located above structure are considered roof drains and are therefore sized and routed by the mechanical engineer. The area drains outside of the lower level limits were sized using the modified orifice (Eq. 3a) to determine the minimum allowable area of each inlet. A 50% clogging factor was included in the design and sizing was based on 100-year peak runoff rates. Inlet Al is an on grade trench drain proposed across the exterior snowmelted concrete driveway, south of the proposed residence. This inlet accepts surface runoff from developed Basin A and was designed with a 50% factor of safety against clogging. Inlet B1 is a sump trench drain proposed within the exterior snowmelted concrete autocourt, southwest of the proposed residence. This inlet accepts surface runoff from developed Basin B and was designed with a 50% factor of safety against clogging. Inlet Cl is a sump inlet proposed within the landscaping zone on the south side of the proposed residence, just south of the proposed garage. This inlet accepts surface runoff from developed Basin C and was designed with a 50% clogging factor of safety against clogging. Inlet D1 is a sump trench drain proposed within the terraced patio on the west side of the proposed residence. This inlet accepts surface runoff from developed Basin D and was designed with a 50% factor of safety against clogging. Inlet El is a sump trench drain proposed within the terraced patio on the west side of the proposed residence. This inlet accepts surface runoff from developed Basin E and was designed with a 50% factor of safety against clogging. RECEIVED 810/1e6/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Inlet F1 is a sump inlet proposed within the lower terraced patio on the west side of the proposed residence. This inlet accepts surface runoff from developed Basin F and was designed with a 50% factor of safety against clogging. Inlet 11 is a sump inlet proposed within the landscaping zone on the east side of the proposed residence, just east of the proposed garage. This inlet accepts surface runoff from developed Basin I and was designed with a 50% clogging factor of safety against clogging. Inlet J1 is as sump inlet proposed within the landscaping zone on the east side of the proposed residence, just east of the exterior light well. This inlet accepts surface runoff from developed Basin J and was designed with a 50% factor of safety against clogging. Inlet K1 is a sump inlet proposed within the landscaping zone on the east side of the proposed residence, just south of the exterior site stairs. This inlet accepts surface runoff from developed Basin K and was designed with a 50% factor of safety against clogging. Table 3 summarizes the minimum allowable inlet areas required to intercept corresponding 100- year peak runoff rates based on a 50% clogging factor. In addition, the recommended inlet type, No pipe number of inlets and associated available areas are included in this table. provided calculatic Table 3: Inlet Design Summary greater tl I.D. CONTRIBUTING Q100 H MINAREA(sf) INLETGRATE GRATE AREA storm. BASINS (cfs) (ft) (w/50%CLOGGING) PROVIDED(sf) INLET Cl BASIN1C 0.020 0.33 0.01 NYLOPLAST6"DROP IN 0.07 INLET F1 BASIN1F 0.056 0.17 0.06 NYLOPLAST6"DROP IN 0.07 INLET II BASIN1I 0.012 0.42 0.01 NYLOP LAST 6"DROP IN 0.07 IN LET 11 BASINII 0.022 0.33 0.02 NYLOPLAST6"DROP IN 0.07 INLETKI BASIN1K 0.032 0.50 0.02 NYLOPLAST6"DROP IN 0.07 LOCATION CONTRIBUTING Q100 H MIN LENGTH(ft) INLET GRATE GRATE LENGTH BASINS (cfs) (ft) (w/50%CLOGGING) PROVIDED(ft) INLET AI BASIN IA 0.049 0.02 10.37 ACO 6' TRENCH 13.00 INLET B1 BASIN 1B 0.255 0.10 4.83 ACO 6"TRENCH 40.00 INLET D1 BASIN 1D 0.032 0.10 0.61 ACO 6"TRENCH 15.00 INLET El BASIN 1E 0.085 0.10 1.62 ACO 6"TRENCH 27.00 All inlets recommended within Table 3 can be supplemented with an alternative product provided the minimum allowable areas are met. Vegetative Swales are proposed at one primary location on the north side of the subject property. The proposed dimension and size of the primary swale was confirmed using Hydraflow Express with the proposed swale's minimum and maximum slopes. Hydraflow Express utilizes Manning's Equation (Eq. 4) below in its analysis. Eq. 4: Q = 1.49/n * (A/Pw)2/3 * A * SO.5 Q=Channel Capacity(cfs) n = manning's runoff coefficient(native: n =0.027) A=Area of flow(sf) Pw=Wetted perimeter of channel (ft) S=Channel longitudinal slope (ft/ft) RECEIVED 910/-1e6/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Swalel collects surface runoff from Basin 1 L and routes collected runoff to drywell DW-A for water quality treatment of impervious areas within the basin. The design considered 100-year peak runoff rates, a roughness coefficient of 0.027, maximum side slopes of 3:1, and corresponding average longitudinal slopes. The size, shape and design results for this swale is summarized within Table 4 below. Table 4: Swale Design Summary SWALE 1 @ 4.0% STORM CONTRIBUTING Q n VELOCITY d EVENT BASINS (CFS) (FT/SEC.) (FT) 5-YR BASIN 1K _ 0.005 0.027 0.67 0.05 100-YR BASIN 1K 0.032 0.027 1.32 0.09 Storm Sewer sizing was verified by using StormNET Software. StormNET uses the Manning's equation to compute the flow rate in open channels and partially full closed conduits. PVC SDR 35 pipe is proposed for all storm sewer conveyance pipes and a Manning's roughness coefficient of 0.013 was used. Storm pipes have been sized to accommodate the peak runoff rates associated with a 100-year storm event. Given the design overflow outlet pipe invert elevation associated with DW A, stored water will back up some of these associated drain lines causing these drain pipes to be inundated. Under these scenarios Hazen-William's equation was selected in StormNET to analyze the system under pressure conditions where applicable. In addition, hydrodynamic link routing was selected. This approach solves the complete St. Venant equations throughout the drainage network and includes modeling backwater effects, flow reversal, surcharging, pressure flow and interconnected ponds. Hydraulic grade lines and energy grade lines were also estimated using StormNET software. StormNet Software calculates the maximum EGLs and HGLs for all structures and storm sewer pipes. It also provides an illustrational depiction within the model's user interface; however it only provides output information for the maximum HGL for each structure and conduit. The HGL, a measure of flow energy, coincides with the level of flowing water at any point in the conduit and includes friction and form losses. The difference between the HGL and EGL is the velocity head; therefore if the HGL is known the EGL can be calculated by adding the velocity head to the HGL line. StormNet output for HGLs and velocities within the corresponding conduits were used to determine the associated EGLs. The results indicate that the storm sewer pipes are adequately sized to accommodate the 5- and 100-year storm events. Outfall Structures StormNet Software was used to design the 100-year outfall structures. When outfall openings are completely submerged StormNET uses the orifice equation (Equation 3). The design allowable discharge is then calculated based on the resultant water surface elevation. The results of this analysis are provided within the Appendix B. In addition, orifice flow check calculations to confirm StormNet output is also provided within Appendix F. H. Water Quality Treatment Water quality treatment for the proposed impervious areas will be achieved through the use of permeable pavement and a dry well. This section describes the sizing and design of each of these proposed water quality treatment facilities. RECEIVED 10iP0a/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 Green Roofs are structural roof components that filter, absorb and retain/detain stormwater runoff. The water quality benefits of green roofs include: biological uptake of stormwater runoff, evapotranspiration, moderates stormwater runoff temperatures, and reduces peak runoff rates and volumes by decreasing the amount of impervious area typically associated with traditional roof systems. Currently this project is proposing approximately 780+/- square feet of green roof areas throughout the project. The project is anticipating to utilize the proposed green roof area to reduce overall site imperviousness in accordance with Low Impact Design principles. The proposed green roof areas above structure area is not currently anticipated to provide additional onsite water quality capture volume treatment consistent with the details provided in Section 8 of the URMP. Dry Wells (DW) are water quality treatment BMPs that incorporate manhole structures with integrated perforated barrels at deeper depths. Cleaned screened rock backfill is provided around the exterior of the perforated sections to promote subsurface infiltration. Runoff that is routed to the structure is stored for a maximum 24hr time period and is allowed to infiltrate into the surrounding soils. When underlying soils are capable of moderate to high infiltration rates, dry wells are considered to be viable BMPs. Dry wells can be implemented to attenuate the increased runoff from proposed impervious areas thereby improving the water quality of stormwater runoff for the subject property. Two drywells are proposed for the development. Further discussion of the respective drywell design parameters can be found below. DW-A is located in the north portion of the subject property within a proposed landscaping buffer separating the property from Snyder Park to the north. The proposed drywell will collect surface runoff generated from onsite impervious areas such as elevated roof structures, on grade terraced patios and snowmelted concrete autocourt. DW-A is designed to accept surface water runoff from develop conditions Basins 1 as depicted on Sheet C-6 of the attached permit drawings. The primary design objective of DW-A is to provide the required minimum water quality capture volume associated with the proposed improvements contributory to the dry well. However, major development projects (which this project qualifies as) not directly connected to the City's stormwater collection system are required to detain surface runoff to the 5- and 100-yr historic peak flow rates. As such the proposed DW-A was additionally analyzed to verify compliance with the minimum detention volumes required by Section 8.5.4.2 of the URMP. A conservative infiltration rate of 5 in/hr was assumed for the underlying soils. The perforated barrel section will be placed a minimum of 10-ft away from proposed structures. Flows that exceed the capacity of the dry well will bubble up through the drywell rim and discharge out of the emergency overflow pipe to an existing rip rap lined channel directly linked to Snyder Park. A shallow berm is provide above the drywell rim to ensure excess runoff is collected within the overflow pipe and to verify the pipe has adequate free board under 100-yr peak flow conditions. This existing outfall location and elevation determined the maximum invert elevation for the proposed drywell overflow pipe. The proposed emergency overflow pipe will be retrofitted with an orifice restricting the 100-yr storm to historic peak levels. The design standards within the URMP require a minimum 10' drywell depth. Peak flow analysis for this project has shown that the discharge volume from the 5-year developed conditions will be completely contained within the proposed drywell. Accordingly, no 5-year discharge orifice has been provided within the drywell overflow pipe outlet works. DW-B is located in the south portion of the subject property within limits of the proposed snowmelted concrete driveway. An existing trench drain extending perpendicularly across the driveway collects surface runoff from the portion of the driveway that is outside of the existing property boundary and cannot be directed onsite. This drywell has been size to provid eEIVED 111P0ae6/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 required water quality capture volume for the proposed impervious driveway, as well as full retention of the 100-yr developed runoff per Section 8.5.4.2 of the URMP. Flows in excess of the drywell's capacity will bubble up through the existing trench drain and continue down the driveway into the curb and gutter within the east side of Midland Avenue and conveyed towards Snyder Park. Drywell volume does n Table 5 summarizes the design results for the proposed drywells. Supportin alcLWQCV. Please enlargE provided within Appendix D. WQCV requirements. Table 5: Water Quality Design Sum DRY WELL CONTRIBUTING TOTAL AREA % WQCV SAFETY REQ.WQC IAMETER DEPTH NO.OF DRYWELL ID BASINS (SF) IMPERV (IN) FACTOR (CF) (ft) (ft) DRY WELLS VOLUME(CF) DW BASIN1A-J 11,364 64% 0.17 1.5 241 5 10 1 196 DW BASIN2 1,000 84% 0.19 1.5 24 4 10 1 126 I. Stormwater Detention As mentioned above, one of the objectives of this report was to ensure peak developed runoff rates do not exceed historic levels contributory to Snyder Park. Since the proposed improvements will result in an increase in peak runoff rates compared to historic land use, stormwater detention will be required. StormNet software was used to route and model the conveyance of runoff through the developed site as well as through the proposed drywell detention facilities and corresponding outfall structures where applicable. A conservative infiltration rate of 5 in/hr was used when modeling the detention basin, however field testing has indicated higher infiltration rates of approximately 120 in/hr at the depths of anticipated drywell barrel perforations. DW-A has been selected to provide stormwater detention volume for Basin 1 and its associated sub basins. Overflow runoff rates out of the drywell will be directed to an existing rip rap line channel leading directly into Snyder Park. Flowrates from the sub basins will be attenuated through the proposed drywells and peak runoff rates to Snyder Park will be reduced to historic peak discharge rates. The proposed DW-A was initially sized to meet the primary design objective of providing adequate water quality treatment volume for the impervious area associated with the proposed improvements. Cumulative basin area and impervious percentage were calculated for the sub basins contributory to the proposed drywell. The required WQCV storage volume was then calculated based on a conservative MCIA reduction value of 0. The results of the required WQCV for the basin and the amount provided within the drywell can be found in Section H above. The second component of the detention facility is to verify flow out of the drywell are reduced to historic peak 5-year discharge rates. The cumulative runoff rates for the contributory basins to DW- A were calculated given design assumption of a 5 minute minimum time of concentration for the contributory basins. StormNET software was used to model the routing of flows through the drywell and connecting stormwater collection pipes. StormNET analysis indicated that the runoff from the 5-yr storm event was completely contained within the drywell, and produced zero flow through the emergency outlet pipe. This is due to the fact that the available storage volume provided within the drywell, associated stormwater collection pipes and overflow containment basin exceeds the total runoff volume from a 5-year storm event. RECEIVED 12 iP0are6/2 017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 The third objective of the detention facility is to provide adequate storage volume resulting from attenuation of the developed 100-year peak discharge to historic levels. An overflow pipe has been incorporated within the overflow containment basin and discharges to the existing rip rap lined channel connected to Snyder Park. Given existing site constraints, the outlet elevation of the overflow pipe could not be lowered and directly connected to the upper chamber of the proposed drywell. As a result, storm events in excess of the drywell's storage capacity will bubble out of the top of the drywell and discharge through a designed orifice installed in a vertical riser integrated within the overflow pipe. The required storage volume to attenuate the 100-year storm event was calculated using Modified FAA detention analysis software "UD-Detention" prepared by the Urban Drainage and Flood Control District. The required storage volume was calculated to be 178 cubic feet. The total available storage volume within the barrel sections of the proposed drywell is 198 cf, which provided more than enough storage volume to attenuate 100-year peak discharge rates to historic levels. DW-B has been selected to provide stormwater detention volume for basin Basins 2. Overflow rates in excess of the drywell's capacity will bubble up through the existing trench drain and continue down the driveway into the curb and gutter within the east side of Midland Avenue. DW-B has been sized to retain the full runoff volume for the 100-year storm event consistent with the URMP design requirements for drywells without controlled outlets. The required full retention volume for DW-B is 45 cf. The available volume within the barrel section of the 10' deep drywell proposed is 126 cf. There is a possibility that the neighbor's driveway may be improved in the future and this drywell could be used to satisfy the water quality/detention requirements for the potential improvements. Table 6: Detention Design Summary STORAGE CONTRIB. 5-YRHIST. 5-YRWSE 5-YRSTORAGE 5-YRDEV. STORAGE CONTRIB. 100-YRHIST. 100-YRWSE 100-YRSTORAGE 100-YRDEV. ID BASINS RUNOFF(CFS) (ELEV) VOLUME(CF)„RUNOFF(CFS) ID BASINS RUNOFF(CFS) (ELEV) VOLUME(CF) RUNOFF(CFS) DW-A BASIN 1 0.10 7965.97 216 0 DW-A BASIN 1 0.71 7970.15 298 0.67 DW-B BASIN 2 0.01 7956.30 45 0 DW-B BASIN 2 0.07 7959.55 86.10 0 For simplicity, storage volumes above depict volume provided within the drywell only, and do not account for available storage within the gravel backfill or within stormwater pipes connected to the drywell. The provided detention volumes for the proposed drywells meet the requirements of the URMP; therefore no Fee In Lieu of detention is proposed for this project. 100 yr storage volum J. Low Impact Design detention volumes are the detention depress Low Impact Design (LID) is a stormwater management strategy that aims to control stor calculations on how F the source by promoting infiltration, evaporation, filtering and detain runoff close to its source. The LID techniques that have been incorporated into this project's stormwater mitigation plan include: disconnecting impervious areas where practical, reducing impervious areas, reducing peak runoff rates and volumes, and incorporating water quality treatment facilities. Below is a list of the 9 Principles outlined within the URMP as well as the ways this project has attempted to implement these principles. • Principle #1-"Consider stormwater quality needs early in the design process": SE was brought on early in the design phase to provide input to grading and drainage challen es RECEIVED 13 iP0ae6/2 017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 and requirements for the proposed improvements. The results were the implementation of green roofs, a drywell and an overall reduction in impervious areas. • Principle #2-"Use the entire site when planning for stormwater quality treatment": The stormwater mitigation approach outlined within this report integrates numerous water quality treatment facilities for managing and treating stormwater runoff. All available and usable areas were used in the design of the water quality treatment enhancements proposed for this project. • Principle #3- `Avoid unnecessary impervious areas": Pervious landscaping roof treatment has been utilized in portions of the proposed structure to help reduce overall site imperviousness. • Principle #4- "Reduce runoff rates and volumes to more closely match natural conditions": The implementation of green roofs and detention drywell reduces overall imperviousness and peak runoffs compared to the existing site. • Principle #5- "Integrate stormwater quality management and flood control": The proposed drywell will provide storage detention volumes as well as improve the quality of site generated stormwater runoff. • Principle #6- "Develop stormwater quality facilities that enhance the site, the community and the environment": Coordination with the Landscape Architect has resulted in stormwater mitigation elements that are aesthetically pleasing and at the same time enhance the stormwater runoff generated from the site. • Principle #7- "Use a treatment train approach": Green roofs and reduced site imperviousness prior to discharge to the drywell help provide a treatment train of surface water runoff and provide a disconnection to surrounding impervious areas. • Principle #8- "Design sustainable facilities that can be safely maintained": There are no risks associated with maintaining the proposed BMPs. A full maintenance plan has been provided within Section M of this report. • Principle #9- "Design and maintain facilities with public safety in mind": The current drainage design poses no risks to public safety; in fact the proposed system will improve the water quality of the stormwater runoff and the peak runoff rates will be reduced. K. Maintenance Plan This section describes the stormwater management systems proposed for the project as well as the associated maintenance anticipated with these improvements. All of the stormwater mitigation improvements will be owned and maintained by the property owner and the following maintenance program should be followed to ensure proper functioning of the proposed improvements. Dry Well: Inspection of the structure should occur annually to remove sediment and debris that is washed into them. Other items that should be inspected include: ✓ Inspect the filter fabric on the bottom of the infiltrating surface at least twice a year; preferably after snow melt in the spring and late fall. RECEIVED 141 P0ae6/2 017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 ✓ Verify that the structure is infiltrating properly. This can be confirmed by inspecting the chamber 24 hours after a rainfall event. If standing water is encountered clogging should be further investigated and remedied. ✓ Remove sediment, debris, trash and any other waste accumulated within the structure. Dispose of this material at a suitable disposal site and in compliance with local, state and federal waste regulations. ✓ Replace the geo-fabric at the bottom of the structure when it appears saturated with sediment or infiltration time is slow. Replacement fabric should be attached to the concrete wall of the structure. ✓ Annually, after a large rain event or with a water hose, evaluate the drain-down time of the structure to ensure the maximum drain time of 24 hours is not being exceeded. If drain- down times are exceeding the maximum, drain the dry well via pumping and clean out the percolation areas. If slow drainage persists, the system may need to be replaced. Storm sewers and Inlets: Inspections of storm sewer piping and inlets should be performed by a person who is familiar with the operation and configuration of the system. ✓ Inspection of all storm pipes and associated inlets should occur at least quarterly for the first two years of operation and then at least twice a year thereafter, if a reduced inspection schedule is warranted based on initial two years of inspection. Strong odors may be a good indication that the facility is not draining properly. ✓ Inspection of inlets and grates should occur at a minimum every spring melt, early and late fall and after any significant rainfall event. Any debris on or around the grated inlets should be removed. Vegetation around the inlet should be trimmed and or cut from the perimeter of the grate. Remove any weeds or invasive root material around all inlets. Inspect drain inlet riser pipe to the invert and remove any debris and securely replace grate. L. Sediment and Erosion Control/BMPs Current practice standards provide parameters for mitigation of drainage and soil erosion activities relative to site development. These parameters are referred to as best management practices (BMP's). These BMP's are primarily grouped for two stages of the development, the construction phase and the post-development phase, with the main emphasis on soil erosion and sediment transport controls. During the construction phase for the proposed improvements the contractor will have to prepare and provide a Construction Management Plan (CMP) that will address site erosions, dust control and disturbed ground stability. Final construction stages of work must follow a complete landscaping and ground covering task to permanently re-vegetate and cover bear grounds that will remain open space to avoid long-term soil erosion. This effort will reduce the risk of unnecessary degradation of the City's drainage system. Temporary erosion control structures installed during construction shall be left in place as necessary and maintained until new vegetation has been re-established at a 70% level. Upon reaching a satisfactory level of soil stabilization from the new vegetation, all erosion control structures shall be removed. RECEIVED 15i130a/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen, Colorado July 21,2017 M. Conclusions This design was prepared in accordance with the COA URMP. Existing and post development drainage basins have been delineated based on survey topography and proposed design. Peak runoff rates associated with these basins were studied to compare historic and post development conditions. In addition, post development peak runoff rates were used to size stormwater infrastructure and post development drainage basins were analyzed to determine the water quality capture volumes required for each basin. Water quality treatment areas were then designed and integrated into the site improvements. All proposed stormwater pipes and inlets have been sized to accommodate the 100-year storm event and therefore meets the criteria as outlined within the COA URMP. The results of the analysis indicate that no increase in surface runoff to Snyder Park with the proposed development improvements. The City's 9 principals to managing stormwater runoff have been implemented into the design and a descriptive maintenance plan for all proposed stormwater infrastructure has been provided. Finally, Best Management Practices (BMPs) have been identified and will be implemented during the construction of the improvements. N. References The following references were used for this drainage report: • City of Aspen Urban Runoff Management Plan (URMP) • Urban Drainage Flood Control District Manual Vol. 3 (UDFCD) • UDFCD Spreadsheets: UD-Rational v1.02a • HP Kumar; Subsoil Study for Foundation Design, dated March 8, 2017 RECEIVED 16 iPo fe6/2 017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue,Aspen,Colorado July 21,2017 O. Engineer's Statement of Design Compliance I hereby affirm that this report and the accompanying plans for the site drainage mitigation of the property located at 108 Midland Avenue, known as the Sandler Residence, was prepared under my direct supervision for the owners thereof in accordance with the provisions of City of Aspen Urban Runoff Management Plan and approved variances and 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 by others. a] 28377 a '.o-1 121/I7/4t; Yancy Nichol License No. 28377 Licensed Professional Engineer,State of Colorado RECEIVED 171P0a/e6/2 017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT S OPRIS ENGINEERING,LLC. AL CIVIL CONSULTANTS I n SHORING/EXCAVATION 502 MAIN STREET AR(s DALE,ao1 162 6"INSPECTION C a RISER BROUGHT F.:I47RI-roa0a,s WITHIN 6"FROM SURFACE W/ SOLID RIM Al'FRAME&GRATE (SEE PLAN) I�L• /� FF lumossf® ITII. 4' ifi In 4"SOLID FOUNDATION DRAIN PER PLANS EMI 73, 11111 e m NUl I� 6(1-1/2" ^ .CRUSHED NO _ STONE m$ MDDIININV= OUTSIDE�' MD DRN INV. n 7971.16' II! M �C MH 7971A6' ;u o 1 PERFORATED 12• ArEM_ : �_••i L \ ~O o c g b S4 09 DATE: XX-XX-XX RISER SECTION MIN. a '- .. eQ'aNi. •< c \ 8 m 0�8 " '' FND DRN INV= 17010111 SUMP P• ,Q /��O� ,C FND DRN INV-- F ;0 3°0 0 795751' JOB NO. R...A..§61.=•01 4;"6- 7971A5' END DRN INV. ' < < <3 of F < < < < e m$ m8 'Dr.I• 00 FND DM INV ft 90.END 7971.00' �_ 4 —1 FND DRN INW "0 .00 C CONNECT TO LOWER DRAIN c� 3 otl 795757. O 0l(�' WI S(1l1D PIPE= V mac`.'' /// ► 0 0 I g w 3�o °o Fi9s7.�'INV. 12" �O��gO��g`- 7971.00' FND ORN INV= / �`� v/ ..._ - ♦ ._ - .o..10:o• In ^o <_<_<_[ <_<_<�<_<3 F /000 ALDEr 7957.19' / END DRN INV= r.o.F.-era r.o.F.=eta .o.F.=ar-g• I o�< N N < -.�n0 0 FND DRN INV. .or.=e2 795]2T rFND DRN INV. n 3 ❑ O In PERIMETER DRAIN DRY WELL TYPICAL DETAIL 7957' 9 / — 79s7s4 — I FND DRN INV= / / ❑ ❑ ► 4 FND DRN INV= N.T.S. 7957.13' // FND DRN INV. V a ►I 7957.56' I t T n / 7957.25' — I—NOTES: // 4 ► 4 D I �/• 0 D J 1. ALL STRUCTURAL RECOMMENDATIONS AND DETAILS PER STRUCTURAL ENGINEER MUST BE //���J In ADHERED TO. i p 7 I In 2. ALL FOUNDATION DRAINS SHALL BE PLACED ATA BIN SLOPE OF A UNLESS OTHERWISE //, ill ❑ ,I I — In NOTED ON PLANS. _ r / 4 3. ALL FOUNDATION DRAIN LINES TO BE RIGID:FLEXIBLE PIPES ARE NOT ACCEPTABLE UNLESS i.o.F.=e26a'v// / I I r————-, I OTHERWISE NOTED ON THE PLANS. / / ,, I I LI i r.o.F�e2-a 0 4. SUMP TO BE SET A MIN.OF3-FT BELOW INCOMING PIPE / / O I II! ri I I 1 r—7 In ood w y/� �' / L J I ❑ D p In FND DEN INV' z 0 ]95].92' w FND DRN INV- w > J D:F: ° /l i / , I MD DRN INV= 7957.R4' Q < O �� // / P 71 L----J I pI 7957.79' F✓7 0 0 w / / —� YQw 0 0 3- 4'DIA.FOUNDATION DRAIN / / L — i II MANHOLE W/INSPECTION V// MD DRN INV e1 D Li 1 ❑ I p/ DDRNDPI4 I-/ L J I IFOUNDATION DRAIN PLAN LEGEND J II ❑ II 1 I I CO >- PROPOSED 4"RIGID PERFORATED DRAIN PIPE // / m„ / `———_I L—_I L————J I J U PROPOSED 4"RIGID DRAIN PIPE V / ' „� I , ARCHITECTURAL I I- FND DRN INV. / boo / 0 ELEVEATION 100'= I I MD DRN INV-0 ]957 BR // n ~~ / L J — CIVIL ELEV 7775.416] ' I I PROPOSED FOUNDATION DRAIN DRY WELL INV SOLID 4"PVC=7956.9 0/ / o TOP OF FOOTER= / _ EV=7J I I / �r , rCIVILE 7=J958.3J r TOS=TOP OF STRUCTURE FND DRN IMF- `, 7 ILID 4 I4 '4 I INV=INVERT 795702 FND DRN INV= / 1 2 II ❑ 3 ❑ I� FFE=FINISHED FLOOR ELEVATION 7957 / / — L J L—J VB=VERTICAL BEND `/ / — L____ I I ; r...- / \ I� I\-FNDDRN INV. A A g,4 Z/ \\ 7957.65' 3.F F F F .L J T°1-14 FND DRN INV. " q T - 7957A1' � _ o ` 7. /// 6 o \ I� MDDRN INV. w FND ORN INV. A M'DRNI = 0 FNDDRNINV= 18. 7 ) I $g 795753' 3 7 795759' 7957.61' 4"RIGID PERF.PIPE@ 3 0.5%MIN.SLOPE F E. a2a ' n\ I 4"FLEXIBLE PIPE \ I ACCEPTABLE FOR THIS $U++A ,.• , CURVATURE OF WALL M1. 4 � I (MIN.SLOPE OF I%)''',.,4'. t> —J MD DRN INV. 'DD' M. DATE REVISION 7957AZ 795752' CAP TOP WITH SILTY OR CLAYEY ON-SITE 501E(OR PAVED SURFACE) TOP FOUNDATION WALL EXISTING GRADE\ SLOPE PER OSHA \\\`` (PER STRUCTURAL) \ DRAIN MAT REQUIREMENTS(OR PROVIDE--\\\ (BY OTHERS) STABILIZED SHORING) 3-IN\ FILTER FABRIC\\\ USE H MINUS BACKFILLRUNOR OVER SELECTSCREENEDROCK EE a OFE EAETA2 PIT RUN OI SEND R O OV FREE OF MPA T T O9,%STANDARD ROCK OVER 3"DIA. FOUNDATION RN GRAVELROCK COMPACT T090%STANDARD PROCTOR IN I2"LIFTS USE 1 N.2"SCREENED ROCK o PLACE MIN.2 FEET ABOVE PIPE g o 2.0'] GRAPHIC SCALE MIN FOOTER 5 0 2.5 5 10 20 BTM FTR (PER STRUCTURAL) - iall II TITLE o TO INV PIPE 4"0 RIGID PERFORATED FOUNDATION DRAIN PIPE \ 24 @O.5%MIN.SLOPE Feet 8��m FI,!y1 o CONNECT4"O PERFORATED COLLECTION PIPE TO SCALE=1"=$' ��// 'Nl�pp�yeT_��®,' 4"O SOLID DRAIN CONVEYANCE PIPE AT END OF WALL AND ROUTE TO DESIGNATED DRY WELL ��� • �• " :16,11 =7 En) = FOOTER DRAIN DETAIL N.Ts. Know what's below. DRAWING o Cali before you dig. °Q (1 6/2 0 17 FOR8 CALL 2-BUSINESS DAYS IN ADVANCE U DIG.GRADE.OR EXCAVAit MARKING OF UNDERGR MEMBER UTD,IES oUNe 'IAV _\7 BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX A Urban Drainage Runoff Spreadsheets 5- and 100-yr Historic Conditions RECEIVED SOPRIS ENGINEERING • LLC civil consultjr s,16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASINI I. Catchment Hydrologic Data Catchment ID= 1 Area= 0.258 Acres Percent Imperviousness= 0.00 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 5 years (input return period for design storm) C1 = 49.40 (input the value of C1) C2= 7.80 (input the value of C2) C3= 0.924 (input the value of C3) P1= 0.64 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.15 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.15 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration ("lland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.1676 18 0.15 N/A 0.10 2.87 1 0.0560 72 2.50 0.59 2.03 2 0.7625 33 2.50 2.18 0.25 3 0.0300 60 2.50 0.43 2.31 4 5 Sum 183 Computed Tc= 7.46 Regional Tc= 11.02 User-Entered Tc= 7.46 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= 2.55 inch/hr Peak Flowrate,Qp= 0.10 cfs Rainfall Intensity at Regional Tc,I= 2.10 inch/hr Peak Flowrate,Qp= 0.08 cfs Rainfall Intensity at User-Defined Tc,I= 2.55 inch/hr Peak Flowrate,Qp= 0.10 cfs RECEIVED BASIN1-HIS-Syr.xls,Tc and PeakQ 7/21/20T7,9: 1 AIVI 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: HIST.BASIN 1 I. Catchment Hydrologic Data Catchment ID= HIST1 Area= 0.263 Acres Percent Imperviousness= 0.00 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.50 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.15 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.1676 18 0.15 N/A 0.10 2.87 1 0.0560 72 2.50 0.59 2.03 2 0.7625 33 2.50 2.18 0.25 3 0.0300 60 2.50 0.43 2.31 4 5 Sum 183 Computed Tc= 7.46 Regional Tc= 11.02 User-Entered Tc= 7.46 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= 5.38 inch/hr Peak Flowrate,Qp= 0.71 cfs Rainfall Intensity at Regional Tc,I= 4.43 inch/hr Peak Flowrate,Qp= 0.58 cfs Rainfall Intensity at User-Defined Tc,I= 5.38 inch/hr Peak Flowrate,Qp= 0.71 cfs RECEIVED BASIN1-HIS-100yr.xls,Tc and PeakQ 7/21/20T7,9: 1 AIVI 2°17 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX B Urban Drainage Runoff Spreadsheets 5- and 100-yr Developed Conditions RECEIVED SOPRIS ENGINEERING • LLC civilconsultlrOs/16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1A I. Catchment Hydrologic Data Catchment ID= 1A Area= 0.012 Acres Percent Imperviousness= 65.50 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.66 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.50 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• ("lland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.50 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.05 cfs RECEIVED BASIN1A-DEV-100yr.xls,Tc and PeakQ 7/21/20T7/9:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1B I. Catchment Hydrologic Data Catchment ID= 1B Area= 0.051 Acres Percent Imperviousness= 86.00 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.79 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.69 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.69 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.25 cfs RECEIVED BASIN1B-DEV-100yr.xls,Tc and PeakQ 7/21/20T7/9:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1C I. Catchment Hydrologic Data Catchment ID= 1C Area= 0.006 Acres Percent Imperviousness= 0.00 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.50 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.15 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• overland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.15 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.02 cfs RECEIVED BASIN1C-DEV-100yr.xls,Tc and PeakQ 7/21/20T7/9:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1D I. Catchment Hydrologic Data Catchment ID= 1D Area= 0.008 Acres Percent Imperviousness= 54.20 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.61 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.42 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction • E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.42 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.03 cfs RECEIVED BASIN1D-DEV-100yr.xls,Tc and PeakQ 7/21/20T7/9:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1E I. Catchment Hydrologic Data Catchment ID= 1E Area= 0.018 Acres Percent Imperviousness= 80.90 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.75 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.64 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.64 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.09 cfs RECEIVED BASIN1E-DEV-100yr.xls,Tc and PeakQ 7/21/20T7/9:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1F I. Catchment Hydrologic Data Catchment ID= 1F Area= 0.009 Acres Percent Imperviousness= 100.00 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.96 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.90 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.90 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.06 cfs RECEIVED BASIN1F-DEV-100yr.xls,Tc and PeakQ 7/21/20T7/9:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1G I. Catchment Hydrologic Data Catchment ID= 1G Area= 0.051 Acres Percent Imperviousness= 84.30 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.78 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.67 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• overland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.67 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.25 cfs RECEIVED BASIN1G-DEV-100yr.xls,Tc and PeakQ 7/21/20T79:1'3AM1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1H I. Catchment Hydrologic Data Catchment ID= 1H Area= 0.041 Acres Percent Imperviousness= 92.70 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.86 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.78 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.78 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.22 cfs RECEIVED BASIN1H-DEV-100yr.xls,Tc and PeakQ 7/21/2 /9114AIV1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1I I. Catchment Hydrologic Data Catchment ID= 11 Area= 0.003 Acres Percent Imperviousness= 13.30 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.54 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.23 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• ("lland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.23 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.01 cfs RECEIVED BASIN1I-DEV-100yr.xls,Tc and PeakQ 7/21/2 /9114AIV1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1J I. Catchment Hydrologic Data Catchment ID= 1J Area= 0.003 Acres Percent Imperviousness= 4.10 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.51 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.18 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.18 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.01 cfs RECEIVED BASIN1J-DEV-100yr.xls,Tc and PeakQ 7/21/2 /9114AIV1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1K I. Catchment Hydrologic Data Catchment ID= 1K Area= 0.003 Acres Percent Imperviousness= 2.30 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.51 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.17 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• ("lland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.17 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.01 cfs RECEIVED BASIN1K-DEV-100yr.xls,Tc and PeakQ 7/21/2 /9114AIV1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: 1L I. Catchment Hydrologic Data Catchment ID= 1L Area= 0.045 Acres Percent Imperviousness= 9.70 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.53 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.21 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration °veiland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flow Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.21 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.15 cfs RECEIVED BASIN1L-DEV-100yr.xls,Tc and PeakQ 7/21/2 /9114AIV1 2°17 ASPEN BUILDING DEPARTMENT CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: 108 MIDLAND Catchment ID: BASIN 1 I. Catchment Hydrologic Data Catchment ID= 2 Area= 0.023 Acres Percent Imperviousness= 84.00 % NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1*P1/(C2+Td)AC3 Design Storm Return Period,Tr= 100 years (input return period for design storm) C1 = 100.10 (input the value of C1) C2= 10.70 (input the value of C2) C3= 1.080 (input the value of C3) P1= 1.23 inches (input one-hr precipitation--see Sheet"Design Info") III. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= 0.78 Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= 0.67 Overide 5-yr.Runoff Coefficient,C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration -------• ("lland LEGEND Reach 1 Bow Reach 2. 0 Beginning Flaw Direction i E Reach Catchment Boundary NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas& Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.67 N/A 0.00 0.00 1 2 3 4 5 Sum 0 Computed Tc= 0.00 Regional Tc= 10.00 User-Entered Tc= 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at Regional Tc,I= inch/hr Peak Flowrate,Qp= cfs Rainfall Intensity at User-Defined Tc,I= 6.29 inch/hr Peak Flowrate,Qp= 0.11 cfs RECEIVED BASIN2-DEV-100yr.xls,Tc and PeakQ 7/21/20 /9114AIV1 2°17 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX C Hydraulic Conveyance Calculations RECEIVED SOPRIS ENGINEERING • LLC civilconsultarijs/16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Thursday,Jul 20 2017 Swalel 5-yr Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.05 Total Depth (ft) = 1.00 Q (cfs) = 0.005 Area (sqft) = 0.01 Invert Elev (ft) = 7967.35 Velocity (ft/s) = 0.67 Slope (%) = 4.00 Wetted Perim (ft) = 0.32 N-Value = 0.027 Crit Depth, Yc (ft) = 0.05 Top Width (ft) = 0.30 Calculations EGL (ft) = 0.06 Compute by: Known Q Known Q (cfs) = 0.01 Elev (ft) Section Depth (ft) 7969.00 - 1.65 7968.50 1.15 7968.00 0.65 7967.50 v 0.15 7967.00 -0.35 7966.50 'f' ' +0 1 0 1 2 3 4 5 6 7 10/16/2017 Reach (ft) ASPEN BUILDING DEPARTMENT Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Thursday,Jul 20 2017 Swalel 100-yr Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.09 Total Depth (ft) = 1.00 Q (cfs) = 0.032 Area (sqft) = 0.02 Invert Elev (ft) = 7967.35 Velocity (ft/s) = 1.32 Slope (%) = 4.00 Wetted Perim (ft) = 0.57 N-Value = 0.027 Crit Depth, Yc (ft) = 0.10 Top Width (ft) = 0.54 Calculations EGL (ft) = 0.12 Compute by: Known Q Known Q (cfs) = 0.03 Elev (ft) Section Depth (ft) 7969.00 - 1.65 • 7968.50 • 1.15 • 7968.00 • 0.65 • • 7967.50 • 0.15 • • 7967.00 • -0.35 • • t 7966.50 0 1 2 3 4 5 6 7 10/16/2017 Reach (ft) ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX D Water Quality Calculations RECEIVED SOPRIS ENGINEERING • LLC civilconsult1r�s16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project No.17010 URMP SECTION 8.5.4.2 Water Quality I.D. ('7W'4 i - Contributing Basins gPr i ^I IA--L— Ci /, FLO G TOTAL AREA= ti ( 3Com{ (sf) // Jr /// _" ; y ,r /l %IMPERV /p31(0 MDCIALEVEL D r I EFFECT.%IMPERV 603 i v,? — j WQCV(wshd-in) 0 I 1 7 Z I C— H I Safety Factor i 1 F — H / WQCV REQUIRED(CF) If 12"MIN.t1i 1 I 12"MIN. y Z ��� i," DRYWELL VOLUME: Diameter: 6 (ft) Depth: I 0 (ft) Volume (cf): 1°4 '3 -rrJ"Zv1 = -cr(2�)2l 10) = Iq b• 3 c.F" BACKFILL GRAVEL VOLUME: Area: 19‘ 15—(sf) Depth: Co (ft) Void Ratio: 30 (%) Volume (cf): 3':�,cl (N �Ia,9��1o)�0.3) TOTAL VOLUME (cf): 2-30a Infiltration Rate: .5°. (in/hr) Detention Time: Z'c (hr) Hydraulic Conductivity (K): L tc)(td (ft/sec) Safety Fact r: Z IG` (.5: I��+ Nifr f 0. 2-30,2 15, E SF' � 1 2�) 3(on �� 1 �}P` 2"�(zi<-1 \Ac,(10 q4' 1�4 ' L Percolation Area Required: = 4 ). ( Percolation Area Provided = 9ei,Z- RECEIVED SOPRIS ENGINEERING • LLO civil consultaIt0/16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project No. 17010 URMP SECTION 8.5.4.2 j I % Water Qualityl.D. DA) t3 i 4 '` Contributing Basins (5 .1N Z. I I Fro i TOTAL AREA= Ij COO (sf) 4 ax *', /V/ / � ,'% 1' %IMPERV &A MDCIALEVEL 0 ► 3 C EFFECT. %IMPERV Ialt ►,' b } WQCV(wshd in) t tSafety Factor " ► . ► i WQCV REQUIRED(CF) `- ► - 7 ► 12"..MIN. ► 1 '��m.s�e...s. L I �1 17"MIN. DRYWELL VOLUME: Diameter: c (ft) Depth: /0 (ft) Volume (cf): 1 Z '•;'?"- 1C"L2')1CP 1Zs3 BACKFILL GRAVEL VOLUME: Area: 15- i'l (sf) Depth: (p (ft) Void Ratio: (%) Volume (cf): 2-S.3 A. tc.--4-1 1,` 65-, -1)6 )Coy, - TOTAL VOLUME (cf): (S Infiltration Rate: 5- (in/hr) Detention Time: 2'1 (hr) Hydraulic Conductivity (K): (,I sX10 4((ft/sec) Safety Factor: Z �L t��i \/12 \ (�. t AP = 2 C,2) 1 , S.-3— k � 1 .vS-IvO 4= 3a L2) Percolation Area Required: = 30.€5 Percolation Area Provided = }C,A / RECEIVED SOPRIS ENGINEERING • LLC civil consu►tailt9/16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX E Inlet Calculations RECEIVED SOPRIS ENGINEERING • LLC civilconsult3'rs16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT ;i ie 1 iip ! +d i i i i FE l Ft i f 1Qt a ± I Null" 9-1 2-1 c .. _ . S j I i r ' i '^ s, s ! (.) \. t..c gym.........--..,._..._.�•r.S....M_ �... -l ss i ? C..k .---= 13 .:;,?,Co.s-)(p..,-.,)Co,02) ,= 0.o(0 r-cc.,:l > 0,o 4,9 os.c / i ? a ' I `1 N Ler i-' 01.$)(40)(9,i i -, oz . CM cps > 6, 2...cc' et_c \// i4 ' eF r; Ei '_II N' 1 ii I Q 7:- (0,, t(0)(0 tO:i)(0 t c' IP4, i)(9.%0 2) '17.-' e?..1 o 2 as. --;.- ,0.10 2,,.asi N7 F .' 4104T ` 1 i 1 0%-'‘ 6,3(j),SYIS"-)LV,I, / - 0:9-5 arS > 0,OV2- LF-s 1/ _ . I f 111 II L- rr iE i-i 6Z-P 3 13(91S)04)(0‘1 ) -z: I.,,,46, d-ct; > 0,0K-7 (......c.f. / :# 1 INN ;:11 a-.L.- (9,(6) (9.0 -)CO3,s--) (.6)-,A/ _ Din -::: 0,0(,9 els > a of;:-.)"-(0 r,f.-c 7--- J 51 I 1 NJ L,CT I i 4, rk«v .1 (..9-Q` (2,10)(0,01)(p,S")\/ (IAA)C0 AZ) 7-7- 0 s i Cf-5 0,012_ cf-Fs V . ? rRECEIVED il _ [ 10/16/2017 ,, _...._............__...._._..._._..__._. ...._...... ___. ...__........._......._............_.............. ........._.._.._.._....___.__. _ __...._..__._..........._........_............ ASPEN . BUILDING DEPARTMENT l i E EE I Z.(2, a-0 t — 8 MI DUAP,Z A i\J Ler -. { (p,(0)(0.,01.Yoicki(64\AIC0,n) s 0, k '- °io 4-„31� €� — — _—..__ . mow„�n... ..._... ..,._....�. tl Si s ---. i (a,6)(..D,dr')) ,c_V(Vk 01- )CO, a0 • f ' i • f : 3� 3 [• s I EE • f -RECEIVE 10/16/201 / ASPEN __.._-__-_1 BUILDING DEPARTMENT j § J /2§) 01 •_oocnma cc 0I> |aJ»c, - G 4. 11 PIN Ci X A m 0 k % LIJ LLI I- .17 0 # I- \ _1 < \ § / < � _ _ = § 2\ § § ce ii=LE"§ k / ) - L _ >= § ) ce ELC,-i*)1 .11- co w01 § § 0 �,_ } § k = ƒ e0r §[I ) § \ wFOL-_\\ce § 0 . }}i;=!:,7:\ §\ E < L ~ } .6\ ELK \ k%z$7(=5Ey 2E%b&b±§§§ m@6Q2§mm-, =mom=ccEz \ §§///R)+§S \§)2$)/§2§ K&3/))§§%ƒ / - L w § / o En _ § oI-z \ � wo � Ca0 P « m « ) C[ R § § 0 0 I- = Wm § » o / + \ § ± > mp =Luce Oz 0 u) c2 cL zLC » ƒ & / § \ ± 0k - / w § § § j :44 7 " , rit $ < OIL ilij & _ z « = CO� < _ o = o < .. < oe3 ƒ99pv2§$7 § e = « zNe « eaekkF9J BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX F 5-yr StormNET Results RECEIVED SOPRIS ENGINEERING • LLC civilconsult1r�s16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT 108 Midland Ave 5-YEAR ANALYSIS 7-21-2017 SE Job#17010 Analysis Options Start Analysis On Jul 13,2017 00:00:00 End Analysis On Jul 13,2017 01:00:00 Start Reporting On Jul 13,2017 00:00:00 Antecedent Dry Days 0 days Runoff(Dry Weather)Time Step 0 01:00:00 days hh:mm:ss Runoff(Wet Weather)Time Step 0 00:05:00 days hh:mm:ss Reporting Time Step 0 00:05:00 days hh:mm:ss Routing Time Step 30 seconds RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Ave 5-YEAR ANALYSIS 7-21-2017 SE Job#17010 Subbasin Summary SN Subbasin Area Weighted Total Total Total Peak Time of ID Runoff Rainfall Runoff Runoff Runoff Concentration Coefficient Volume (fr) (in) (in) (ac-in) (cfs) (days hh:mm:ss) 1 Basin1A 510.00 0.5100 0.25 0.13 0.00 0.02 0 00:05:00 2 Basin1B 2220.99 0.6900 0.25 0.17 0.01 0.11 0 00:05:00 3 Basin1C 271.99 0.1500 0.25 0.04 0.00 0.00 0 00:05:00 4 Basin1D 364.99 0.4200 0.25 0.10 0.00 0.01 0 00:05:00 5 Basin 1E 784.99 0.6400 0.25 0.16 0.00 0.03 0 00:05:00 6 Basin1F 405.02 0.9000 0.25 0.22 0.00 0.03 0 00:05:00 7 Basin1G 2205.01 0.6700 0.25 0.17 0.01 0.10 0 00:05:00 8 BasinlH 1774.98 0.7800 0.25 0.19 0.01 0.10 0 00:05:00 9 Basinll 150.02 0.2300 0.25 0.06 0.00 0.00 0 00:05:00 10 Basin1J 295.99 0.1800 0.25 0.05 0.00 0.00 0 00:05:00 11 Basin1K 434.99 0.1700 0.25 0.04 0.00 0.01 0 00:05:00 12 Basin 1L 1945.00 0.2100 0.25 0.05 0.00 0.03 0 00:05:00 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Ave 5-YEAR ANALYSIS 7-21-2017 SE Job#17010 Pipe Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) 1 Basin1D-Lateral 0.01 0 00:05 1.40 0.01 1.38 0.02 0.08 0.24 2 Basin1E-Lateral 0.03 0 00:05 1.68 0.02 4.67 0.01 0.12 0.36 3 E-STRM-1 0.07 0 00:16 1.26 0.05 1.87 0.22 0.43 0.87 4 E-STRM-2 0.01 0 00:07 2.97 0.00 3.94 0.12 0.19 0.38 5 E-STRM-3 0.01 0 00:07 1.77 0.01 2.61 0.03 0.03 0.05 6 E-STRM-4 0.01 0 00:07 1.77 0.00 1.64 0.21 0.03 0.05 7 E-STRM-5 0.01 0 00:06 1.82 0.00 2.14 0.23 0.02 0.04 8 E-STRM-6 0.00 0 00:06 1.79 0.00 1.07 0.35 0.02 0.03 9 Link-23 0.10 0 00:05 1.34 0.08 6.98 0.02 0.11 0.32 10 Link-27 0.02 0 00:05 0.49 0.05 1.35 0.08 0.08 0.17 11 Overflow 0.00 0 00:00 0.69 0.00 0.00 0.00 0.00 12 STAIR-INLET 0.00 0 00:06 0.25 0.02 1.55 0.03 0.02 0.07 13 STAIR-1NLET2 0.00 0 00:07 2.65 0.00 3.32 0.01 0.02 0.06 14 W-STRM-1 0.18 0 00:06 0.81 0.22 2.92 0.05 0.50 1.00 15 W-STRM-2 0.18 0 00:06 2.63 0.07 5.37 0.04 0.28 0.57 16 W-STRM-3 0.16 0 00:06 2.64 0.06 6.59 0.02 0.09 0.18 17 W-STRM-4 0.16 0 00:06 0.79 0.20 3.22 0.01 0.15 0.30 18 W-STRM-5 0.13 0 00:06 0.79 0.16 2.12 0.21 0.17 0.34 19 W-STRM-6 0.12 0 00:06 0.69 0.17 2.49 0.11 0.14 0.29 20 W-STRM-7 0.02 0 00:07 0.69 0.03 0.65 1.03 0.10 0.21 21 W-STRM-8 0.02 0 00:05 0.79 0.02 1.75 0.37 0.05 0.11 22 W-STRM-9 0.00 0 00:07 1.87 0.00 0.41 1.20 0.04 0.07 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Ave 5-YEAR ANALYSIS 7-21-2017 SE Job#17010 Storage Nodes Storage Node : Drywell Input Data Invert Elevation(ft) 7955.00 Max(Rim)Elevation(ft) 7970.50 Max(Rim)Offset(ft) 15.50 Initial Water Elevation(ft) 7955.00 Initial Water Depth(ft) 0.00 Ponded Area(ft') 10.00 Evaporation Loss 0.00 Outflow Orifices SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient Diameter Height Width Elevation (in) (in) (in) (ft) 1 Orifice-100yr Bottom CIRCULAR No 5.50 7969.33 0.61 Output Summary Results Peak Inflow(cfs) 0.39 Peak Lateral Inflow(cfs) 0.22 Peak Outflow(cfs) 0.08 Peak Exfiltration Flow Rate(cfm) 1.43 Max HGL Elevation Attained(ft) 7965.53 Max HGL Depth Attained(ft) 10.53 Average HGL Elevation Attained(ft) 7962.13 Average HGL Depth Attained(ft) 7.13 Time of Max HGL Occurrence(days hh:mm) 0 00:20 Total Exfiltration Volume(1000-ft') 0.074 Total Flooded Volume(ac-in) 0 Total Time Flooded(min) 0 Total Retention Time(sec) 0.00 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Avenue Major Design Drainage Study SE Project#17010 APPENDIX G 100-yr StormNET Results RECEIVED SOPRIS ENGINEERING • LLC civilconsult3'rs16/2017 502 Main Street Suite A3 Carbondale Colorado 81623 (970)704-0311 Fax:(970)704-0313 ASPEN BUILDING DEPARTMENT 108 Midland Ave 100-YEAR ANALYSIS 7-21-2017 SE Job#17010 Analysis Options Start Analysis On Jul 13,2017 00:00:00 End Analysis On Jul 13,2017 01:00:00 Start Reporting On Jul 13,2017 00:00:00 Antecedent Dry Days 0 days Runoff(Dry Weather)Time Step 0 01:00:00 days hh:mm:ss Runoff(Wet Weather)Time Step 0 00:05:00 days hh:mm:ss Reporting Time Step 0 00:05:00 days hh:mm:ss Routing Time Step 30 seconds RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Ave 100-YEAR ANALYSIS 7-21-2017 SE Job#17010 Subbasin Summary SN Subbasin Area Weighted Total Total Total Peak Time of ID Runoff Rainfall Runoff Runoff Runoff Concentration Coefficient Volume (fr) (in) (in) (ac-in) (cfs) (days hh:mm:ss) 1 Basin1A 510.00 0.6600 0.53 0.35 0.00 0.05 0 00:05:00 2 Basin1B 2220.99 0.7900 0.53 0.42 0.02 0.26 0 00:05:00 3 Basin1C 271.99 0.5000 0.53 0.26 0.00 0.02 0 00:05:00 4 Basin1D 364.99 0.6100 0.53 0.32 0.00 0.03 0 00:05:00 5 Basin1E 784.99 0.7500 0.53 0.40 0.01 0.09 0 00:05:00 6 Basin1F 405.02 0.9600 0.53 0.51 0.00 0.06 0 00:05:00 7 Basin1G 2205.01 0.7800 0.53 0.41 0.02 0.25 0 00:05:00 8 Basin1H 1774.98 0.8600 0.53 0.45 0.02 0.22 0 00:05:00 9 Basinll 150.02 0.5400 0.53 0.28 0.00 0.01 0 00:05:00 10 Basin1J 295.99 0.5100 0.53 0.27 0.00 0.02 0 00:05:00 11 Basin1K 434.99 0.5100 0.53 0.27 0.00 0.03 0 00:05:00 12 BasinlL 1945.00 0.5300 0.53 0.28 0.01 0.15 0 00:05:00 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Ave 100-YEAR ANALYSIS 7-21-2017 SE Job#17010 Pipe Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) 1 BasinlD-Lateral 0.03 0 00:05 1.40 0.02 2.91 0.01 0.21 0.62 2 Basin1E-Lateral 0.08 0 00:05 1.68 0.05 5.50 0.01 0.20 0.62 3 E-STRM-1 0.60 0 00:06 1.26 0.48 3.16 0.13 0.50 1.00 4 E-STRM-2 0.06 0 00:06 2.97 0.02 5.59 0.08 0.27 0.55 5 E-STRM-3 0.06 0 00:06 1.77 0.04 4.17 0.02 0.07 0.13 6 E-STRM-4 0.03 0 00:06 1.77 0.02 2.25 0.15 0.06 0.13 7 E-STRM-5 0.03 0 00:05 1.82 0.02 3.50 0.14 0.05 0.09 8 E-STRM-6 0.01 0 00:05 1.79 0.01 1.67 0.23 0.04 0.08 9 Link-23 0.25 0 00:05 1.34 0.19 7.98 0.02 0.21 0.63 10 Link-27 3.93 0 00:51 0.49 7.96 20.00 0.01 0.50 1.00 11 Overflow 0.69 0 00:11 0.69 1.00 3.67 0.06 0.46 0.92 12 STAIR-INLET 0.03 0 00:05 0.25 0.13 2.42 0.02 0.07 0.20 13 STAIR-1NLET2 0.03 0 00:06 2.65 0.01 6.39 0.00 0.05 0.16 14 W-STRM-1 0.82 0 00:50 0.81 1.01 4.18 0.04 0.50 1.00 15 W-STRM-2 0.93 0 00:51 2.63 0.35 6.12 0.03 0.50 1.00 16 W-STRM-3 10.61 0 00:50 2.64 4.02 50.00 0.00 0.50 1.00 17 W-STRM-4 1.93 0 00:50 0.79 2.43 9.82 0.00 0.50 1.00 18 W-STRM-5 0.34 0 00:05 0.79 0.42 2.69 0.17 0.50 1.00 19 W-STRM-6 0.31 0 00:05 0.69 0.44 3.01 0.09 0.50 1.00 20 W-STRM-7 0.06 0 00:06 0.69 0.09 1.03 0.65 0.30 0.60 21 W-STRM-8 0.05 0 00:05 0.79 0.06 2.10 0.31 0.09 0.18 22 W-STRM-9 0.02 0 00:07 1.87 0.01 1.26 0.39 0.07 0.14 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT 108 Midland Ave 100-YEAR ANALYSIS 7-21-2017 SE Job#17010 Storage Nodes Storage Node : Drywell Input Data Invert Elevation(ft) 7955.00 Max(Rim)Elevation(ft) 7970.50 Max(Rim)Offset(ft) 15.50 Initial Water Elevation(ft) 7955.00 Initial Water Depth(ft) 0.00 Ponded Area(ft') 10.00 Evaporation Loss 0.00 Outflow Orifices SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient Diameter Height Width Elevation (in) (in) (in) (ft) 1 Orifice-100yr Bottom CIRCULAR No 5.50 7969.33 0.61 Output Summary Results Peak Inflow(cfs) 1.11 Peak Lateral Inflow(cfs) 0.62 Peak Outflow(cfs) 0.69 Peak Exfiltration Flow Rate(cfm) 1.99 Max HGL Elevation Attained(ft) 7970.06 Max HGL Depth Attained(ft) 15.06 Average HGL Elevation Attained(ft) 7966.38 Average HGL Depth Attained(ft) 11.38 Time of Max HGL Occurrence(days hh:mm) 0 00:10 Total Exfiltration Volume(1000-ft') 0.105 Total Flooded Volume(ac-in) 0 Total Time Flooded(min) 0 Total Retention Time(sec) 0.00 RECEIVED 10/16/2017 ASPEN BUILDING DEPARTMENT