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File Documents.688 Spruce St.0119-2020-BRES (31)
Drainage Report 688 SPRUCE S T. City Development Engineer's Comments 1.Encroachments:Any existing or planned encroachments into the public right-of-way,including temporary construction trailers and dumpsters,must be ASPEN CO applied for licensing at City Engineering(920-5080).Five days advance notice is required to obtain a temporary encroachment license. 2.Right-of-way Permits:Approval of these plans by the City Building Dept.is for work on private property only.Design approvals for proposed work (including landscaping)in the public right-of-way(ROW)must be obtained from City Engineering Dept.(920-5080)and Parks Dept.(920-5120).A permit for work in the public right-of-way must be obtained from the City Engineering Dept.five days in advance of when the permit is needed. 3.Mud,dirt and debris may not be tracked onto the adjacent public ROW, and the adjacent ROW must be clean at the end of eachworkday.Construct mud rack if needed.Trucks hauling demolished materialsmust becovered. 4.Utilities in ROW:No utility pedestals,meters,or electric transformers can be installed in the public right-of-way.Provide utility easements on private property as needed. 5.Certificate of Occupancy(CO)Inspection:Engineering CO Inspection includes but is not limited to:(a)witnessing that all property corners havemonuments,(b)drainage improvements were installed as approved,(c) easements are documented,(d)no unapproved ROW encroachments exist, and(e)the ROW has been restored.Call 429-2750 to arrange CO inspection. 6.Snowmelt Driveways:(i)Snowmelt runoff from driveway cannot flow into street.A grate or swale must intercept runoff before street.(ii)Snowmelt installation in the public ROW requires an encroach-ment permit. 7.Drainage Issues:(i)Foundation drains cannot go to a dry well receiving other drainage flows.(ii)City must be notified of drainage plan changes.(iii) Plan approval assumes no ground water.If ground water is encountered,call the Senior Dev.Engineer at 920-5080.Call for an open hole inspection prior October 16, 2020 to placement ofthedrywell. 8.No Loose Material Storage allowed in R.O.W. Comment Responses: 2-18-2021 9.Neighbor Notification:For all excavation,the Contractor must comply with neighbor notification requirements per Section 3307 of the 2003 International Building Code(IBC) Reviewed by Engineering 1 06/30/2021 4:42:06 PM "It should be known that this review shall not relieve the applicant of their responsibility to comply with the requirements of the City of Prepared by Aspen.The review and approval by the City is Richard Goulding, P.E. offered only to assist the applicant's understanding of the applicable Engineering Roaring Fork Engineering requirements."The issuance of a permit based 592 Highway 133 on construction documents and other data shall Carbondale, CO not prevent the City of Aspen from requiring the correction of errors in the construction documents and other data. ROARING FORK ENGINEERING RECEIVED 03/11/2021 ASPEN BUILDING DEPARTMENT Drainage Report 688 SPRUCE ST. ASPEN, CO I HEREBY AFFIRM THAT THIS REPORT FOR THE IMPROVEMENTS AT 688 SPRUCE ST. PREPARED BY ME FOR THE OWNERS THEREOF IN ACCORDANCE WITH THE PROVISIONS OF CITY OF ASPEN AND APPROVED VARIANCES AND EXCEPTIONS LISTED THERETO. I UNDERSTAND THAT IT IS THE POLICY OF THE CITY OF ASPEN THAT ASPEN DOES NOT AND WILL NOT ASSUME LIABILITY FOR DRAINAGE FACILITIES DESIGNED BY OTHERS. RICHARD GOULDING,P.E. _ - - RFE Project#2019-34 RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Table of Contents 1.0 Intro 1 1.1 Existing Site 1 1.2 Proposed Site 1 2.0 Offsite Drainage 1 2.1 Offsite Mudflow 4 2.2 Proposed Curb and Gutter 5 2.3 Proposed Inlets 5 2.4 Driveway Swale/Valley Pan 6 2.5 Proposed Onsite Infrastructure 6 3.0 Low impact Site design 7 3.1 Principles 7 4.0 Onsite Drainage 8 4.1 Drainage Basins 8 4.2 Peak Discharge Calculations 8 4.3 Historic Release 9 5.0 Hydrological Criteria 10 5.1 Storm Recurrence and Rainfall 10 5.2 Storage Volumes Methodology 10 6.0 Hydraulic Criteria 11 6.1 Piping 11 6.2 Inlets 11 7.0 Maintenance 12 7.1 City of Aspen Inlets within Right of Way 12 7.2 Onsite Inlets and Piping—Continuation of the City of Aspen System 13 7.3 Trench Drains 13 7.4 Retention Pond 13 Appendix A—Site Location and Offsite Point of Concentration Photos Appendix B -The Smuggler/Hunter Surface Drainage Master Plan Hunter Creek Basin Delineation Appendix C—Hunter Creek Sub-Basin Delineations and Point of Concentration Locations Appendix D—Curb and Gutter Hydraulics Appendix E—Storm Inlet Hydraulic Capacities Appendix F— 18-inch Concrete Culvert Hydraulics RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Appendix G—Soils Report RECEIVE 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT 1.0 Intro 1.1 Existing Site The property in question is located at 688 Spruce St. in Aspen Colorado. The property is on the north east side of town within the Hunter Creek Drainage Basin. A single-family home currently resides on the property with and asphalt driveway. The area west and immediately adjacent to the home slopes down to the west with slopes varying from 5%to 20%. Further west there is a bluff that drops off to the west with steeper slopes approaching 50%. The vegetation consists of landscaped areas, sod lawn, shrubs, aspen trees and juniper trees. The westside of the property is made up of fill material from previous excavations. Currently,near the north east corner of the property,there is a point of concentration created by the offsite Hunter Creek Drainage Basin. This flow path has been causing issues on the property. This is one of the sub-basin points of concentration for a larger major basin delineated within the Smuggler/Hunter Surface Drainage Master Plan. This report was prepared by URS Corporation for the City of Aspen(COA) dated April 10,2015. A subsurface field exploration took place on September 3,2019 where three borings were dug by Kumar and Associates,Inc. The subsoils below 3 '/2 feet of sand and gravel in boring 1 or 1 to 1 1/2 feet of topsoil in borings 2 and 3, consisted of up to 20 feet of medium dense silty sand and gravel with cobbles and possible boulders.A loose sand layer was encountered below about 15 feet in boring 3.Reference the full Kumar and Associates report for more information in Appendix G.No free water was encountered at the time of boring. 1.2 Proposed Site The proposed development will consist of demoing the existing structure and a new two-story home will be constructed with new driveway, auto-court and patios. The purpose of this report is to propose a solution to mitigate offsite drainage flowing onto the property without impacting downstream neighbors and to show compliance for the onsite drainage design. This project is classified as a `Major Project' per Table 1.1. of the URMP. The proposed development is over 1,000 square feet and disturbs an area of approximately 50,000 feet including right of way and utility work. The intent of this report is to demonstrate compliance with the requirements of the URMP. The Low Impact Design(LID)Principles in the introduction of the manual were used as a guide throughout the design process. 2.0 Offsite Drainage As stated,before there is a point of concentration created by the Hunter Creek Drainage Basin flow path just north of the northern driveway entrance to the property. Google earth areal imagery and street view imagery can be found in Appendix A showing the site location and the offsite point of concentration location. The Smuggler/Hunter Surface Drainage Master Plan analyzed the Hunter Creek Basin. This basin delineation can be found in Appendix B. The point of concentration determined onsite coincides with the sub-basin point of concentration labeled HO1 within the Master Plan. The Master Plan's sub-basin delineation and point of concentration locations RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT can be found in Appendix C. The peak flows are shown below for the Hunter Creek sub-basins can be found in Table 2.7 of the Aspen Hunter-Smuggler Master Plan. Sub-Basin Peak Flow(cfs) ID 2-year 5-year 10-year 25-year 50-year 100-year_ _ Hunter Creek Basin _ HOl 0.1 0.2 0.5 1.5 1.9 8.8 H02 0.1 0.2 0.4 0.8 1.2 2.3 H03 1.3 1.9 2.6 4.3 5.5 8.6 H04 1.8 2.3 2.8 3.7 4.3 5.4 H05 7.2 9.8 12.1 16.1 18.7 22.2 According to the Master Plan the HO1 sub-basin 100-yr peak flow at 688 Spruce St. is 8.8 cubic feet per second(cfs). This peak flow will be used to analyze the proposed storm infrastructure. Within the Smuggler-Hunter Surface Drainage Master Plan the City of Aspen evaluated this area and came up with a conveyance option for mitigating the 10-year Hunter Creek flows. This option proposes to pipe the run off from the point of concentration south down Spruce St.,then west down William's Way. A screen shot of page 141 of the report is shown below Showing the proposed routing and pipe sizing. �:\ (( i i Note:This proposed improvement affects this single property / and ,vill be obligation of the o.vner upon redevelopment. 1. K___ / ---- / K N\__,,_______________,__„„y7----==-----' Ape •• ) / OFALL-.11 1-, I 1•H03 • H01 0 . I People have to sandbag (} . I� �. ..� DO6=HO3 H0 ,yolk \\\<` . i�.�i.D16-H03 '\.',' '\• .`, Hunter Creek Basin : l ��.� 1 H03 ��� `� �:r, Jot Hai I���,��, D09-H03 \ igi _ i AiL.D72-1103 Basement flooding in 2006 storm. 1 .D08-H03 i , .D11-H03 68 ft long private easement for 18-in RCP Dto Ho3 i N l 1{ w • / H05 -748 ft of 18-in RCP;-7 MH:1 FE:riprap apron F 11 L.7--) '''' . . ._,, (---_, ,1 GL-Z,- .16.,..il, - This option requires significant piping and a new easement. A cost estimate was also presented within the plan. The cost estimate table is shown below. RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Table 5.4 Alter utilise Cost Estimates Hunter Creek Basin Construction Subtotal Design Projects Location Size Construction Contingency Construction Contingency Land Cost Total Cost Cost (x$1,0001 (30%) Cost (20%) 10-year Conveyance Alternative 1.Williams Woods Proposed System ft I-iv RCP H-05t0J02-1403 700 $ 86450 5 25.935 $ 112,355 $ 17,290 $ - $ 130 l it RCP Easement 012-H0310 J02-H03 - 68 $ - $ - $ - $ - $ 53,657 $ 54 13-rrs 302-H03 - $ 1,160 $ 357 $ 1.546 5 235 5 - S 2 IQ Proposed system outfon nprop protection J02-H03 3 $ 459 $ 136 $ 597 $ 92 S - $ t Total Coat $ 68,008 $ 26.E $ 114,627 $ 17,620 $ 63,667 $ 166 Another option investigated was to install new curb and gutter along the property to convey runoff all the way down Spruce St. and Race St.to the Fox Crossing development.A previous drainage study was performed by JR Engineering for Kaegebein Fine Home Building on September 1, 2015 analyzing the Fox Crossing Subdivision. JR Engineer used the offsite flow from a previous drainage study/report conducted by Loris Engineering on Febivary`27,2006. Below is a screen shot of page 11 of that report. Te„.,*: ‘g-, ,- 7.1., lig44 ' V, - c„.,j41r, 11)1I\ ,i(,..1 w. * A It_ ` S ' - / \ -t'\ 7 0) A -'tit 4) J / tc'Ir VAK:A,"-= 1-4, 6-1-1".#,V, °t'? ll t r ..l i . k,A ,n , *\- -7\tiii 1 _.. „....\414 -I , 'tN---Al 1 ,, ,i, )1,0- s toil .0." 1.ii, - 'i--- -- 7/--) nv.-i I f, 4, (_.N ttl- '` � t AL -* o / U, I N � �1'4 -----. ,,,,,_ .._II r ,, vb. ,,. Nilo- g: ‘, Fl , -_. , , •4, _rse--, , ‘, , pl,sek , . _ r ( • " •a S t A of) ''l i kt4 w i:i EFF:41"'.... r t, ii 1, -; 4ir 40e7,/ -ram y, , ,1.,_,. 4 ..„—-At4:-_ 1 q .' e1,,vk i „4*c,tp,'i ,.\'N;\1*I,Ai 6 f.41,1,—? ,§4 i' f•1:?,.,dpr..aii 1 ida OttiejfifiN7)111 s A ' kikt II li I,S, :/t 1� ill \; s? Is� ` \ ~� ,✓ �,,� + ) . This offsite basin does not include the Hunter Creek Basin from the Smuggler/Hunter Surface Drainage Master Plan. Due to this we deemed it infeasible to introduce the entirety of the Hunter Creek Basin into the Fox Crossing storm system as it does not have capacity for the additional flows. The option proposed by Roaring Fork Engineering after coordinating with the City of Aspen is to install curb and gutter along the property with four inlets to capture the runoff near the existing 688 south driveway entrance. This runoff will then be piped to a lined retention pond onsite to limit the peak flows RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT to downstream infrastructure. There is also a prevalent mudflow hazard presented and analyzed by the Smuggler/Hunter Surface Drainage Master Plan. 2.1 Offsite Mudflow The Smuggler/Hunter Surface Drainage Master Plan also conducted a mud flow analysis for this area. Below is a screen shot of the 100-year Flo-2d modeling results. The existing structure on the 688 Spruce St. property is highlighted in red. This is a portion of figure 3.6 found in the Drainage Master Plan. -- AI ,r , lir\ --pcc..) -? \ , , J ), ,. ., , .., isi...) \\_.,, . il ,.. il c-2.., .., < , ,\ if C. ‘,,..m..),' '(j',c) \ir.,77 , L (1. 1 \„..7.,.N. .-= , , } ,t `` } .- ,, < , ()) 0 , it* 1 , \--, ,,, i, / :, , , , .. , ( p\,, ,-- . , 1 , 1 ( � t , , , , . , ii 1 1 .,, Ak., -§ 1 t 1• (._ ., rio.. 9 \\ . Ir S , ., ,.„ o li iiii', a ( ___ _., , . --,. ' IP A. • . ,, 4 , t i ct- , iii II- N ;L_ Iv_ '67. • Legend -Buildings Maximum Mudflow Depth(ft) -<1.0 1.0-2.0 2.0-3.0 3.0-4.0 -4.0-6.0 According to the report less than 1-foot of mud acumulates just east of the existing structure. To mitigate this mud flow a 1-foot tall wall has been proposed to the east of the new structure and auto- court. If mud were to reach this wall, grading would convey the mud-flow south along the base of the wall. This prevents the mud from flowing towards the garage door openings. This wall extends north to RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT within 10 feet of the existing water line running across the northeast corner of the property. If mud were to flow north of the wall onsite grading would direct the flows away from the structure. Mud flows deflected by the wall or grading will push flow north or south around the structure into the lawn and landscaped areas. The new wall and structure will not increae the mudflow on the adjacent prperties. 2.2 Proposed Curb and Gutter A 3-foot-wide concrete valley pan is proposed to intercept the drainage coming down Spruce St. and direct it into the curb and gutter. This valley pan should capture smaller flows while large flows overtopping the valley pan will pour down the street and hit the new curb. New concrete curb and gutter are proposed to line the west side of Spruce St. The curb and gutter are to start just north of the northeast property corner and extend south and connect to the existing curb and gutter. The northern driveway entrance is going to be eliminated. The proposed curb and gutter's hydraulic capacity was tested to ensure it could convey the 8.8 cfs. Appendix D shows the Hydraflow Express channel calculations for the curb's capacity. The curb height is 6 inches tall and the gutter width is 24 inches. The gutter is sloped at 1 inch per foot(8.33%)toward the flow line,while the road is sloped at 2%to the edge of the gutter. The longitudinal slope is 4%with the flow being directed from the north to south. The proposed curb and gutter have capacity to convey the 8.8 cfs. 2.3 Proposed Inlets Just north of the proposed driveway entrance there are three proposed inlets with another fourth inlet proposed further south of the proposed driveway. These inlets are conforming to the City of Aspen's standard detail#:ENG—301A. The 100-year event of 8.8 cfs was used to analyze the hydraulic capacity of the first inlet to determine the amount of runoff captured. The uncaptured amount was then used to analyze the second inlet to determine the amount captured. This was done again for the third inlet. Below is a table showing the amount captured and overflows of each inlet.Appendix E shows the hydraulic analysis for each inlet. Upstream (CFS) Captured Amount(CFS) Overflow Amount(CFS) Inlet 1 8.8 3.34 5.46 Inlet 2 5.46 2.47 2.99 Inlet 3 2.99 1.67 1.32 The fourth and final inlet below the driveway entrance is placed within a depression created by the proposed curb and gutter flow line profile. This depression has a max depth of 2 inches and creates a sump condition.Using the 2 inches of possible head above the inlet its capacity was calculated. RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Curb Inlet-4 Sump Capacity Calculation m=40% YS 0.166(Head above inlet=2") Cg=50% Co=0.65 Q Max Inlet Type Inlet Width Inlet Length Effective Open Area(EQ.4-20) Inlet Capacity (EQ4-19) Has Capacity (ft3/sec) Rectangular Wo(inches) Lo(inches) (ft2) Q=CoAeV2gYs (Yes/No) 1.32 29.5"x16.32" 16.32 29.5 0.629 1.336 Yes Curb Inlet-4 can capture the remaining 1.32 cfs.No runoff should bypass this inlet during the 100-yr event or less. 2.4 Driveway Swale/Valley Pan The driveway entrance swale was analyzed using the leftover flow from the third inlet. The first three inlets capture 7.48 cfs of the 8.8 cfs leaving 1.32 cfs to flow across the driveway entrance. The capacity of the flow path crossing the driveway was also tested to ensure the peak flows would not flow down the driveway. The concrete valley pan is 3 feet wide with 8.33%(1-inch per foot) side slopes and a longitudinal slope of 8.00%. The roadway and the driveway continue to rise up perpendicular from the flow line adding to the capacity of the swale. The high point in the driveway is 0.3 feet above the flow line of the valley pan. Although only 1.32 cfs should reach this valley pan due to the up-hill inlets,this 0.3-foot height was chosen so the driveway valley pan could convey the entire 8.8 cfs from the offsite basin.Appendix D shows the Hydraflow Express channel calculations for the valley pan's capacity. 2.5 Proposed Onsite Infrastructure From the inlets 18"reinforced concrete piping will be routed to a lined retention pond on the southwest portion of the property. This pond will have an underdrain system made up of an 8"perforated PVC pipe bedded within 3/4"washed screened rock. The bedding will be wrapped in 140N Mirifi filter fabric.Native material will be used to shape the pond and hold the liner down.A 6-inch layer of top soil will then be placed on top of the fill. The vegetation can be that of native grasses or sod. Flows that enter the under drain are routed to an 18-inch Nyloplast basin with a 4"outlet pipe sloped at 2%. This pipe will restrict the flow to not exceed the historical rate. If the pond fills, overflows will flow into the 24-inch grated manhole lid on the west side of the pond. 8.8 cfs from the offsite Hunter creek basin analysis will need to flow through this pond. The out-fall pipe from the pond was analyzed as it has the shallowest slope of 2%. Hydraulics of an 18-inch pipe were analyzed in Appendix F. The retention pond provides storage to mitigate the new development's storm water but will also be used for the offsite Hunter Creek Basin Drainage. From here grading and rip rap will convey flow to the existing downstream culvert. This is also on 18- inch culver that can convey the 100-yr peak flow. RECEWED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT 3.0 Low impact Site design 3.1 Principles Principle 1: Consider storm water quality needs early in the design process. The grading and drainage designs were coordinated with the architects and the City early in the design to mitigate the offsite and onsite stormwater. Comments from the City and the owners were considered and analyzed. Multiple site visits ensured proper understanding of existing conflicts. Researching past reports also gave the team an understanding of the offsite drainage issues. Principle 2: Use the entire site when planning for storm water quality treatment. Full detention was calculated for the entire impervious area of the site. The south side of the site is utilized for the COA storm piping. Onsite piping surrounds the structure capturing drainage from all imperious areas. The retention pond resides in the south west corner of the property at the lowest point were all drainage will be directed. Principle 3: Avoid unnecessary impervious area. All impervious areas are used for driving,walking or the structure's roof. Principle 4: Reduce runoff rates and volumes to more closely to match natural conditions. All runoff from impervious surfaces will be collected and piped to the retention pond. This pond is designed to retain the total detention requirement for the site while providing a surge buffer for the offsite basin. Principle 5: Integrate storm water quality management and flood control. All inlets and piping are sized to accommodate the 100-year peak flows. Pipes were sized to ensure 100-year flows do not exceed 80%of the pipe capacity. Overflows will discharge into the historic drainage path below the property. The offsite drainage is diverted to a retention pond with a restricted overflow. Principle 6: Develop storm water quality facilities that enhance the site,the community and the environment. The large retention pond will provide storage and filtration/settling for the offsite drainage passing through the property. Principle 7: Use treatment train approach. After runoff has passed through the piping and inlets with numerous sumps it discharges into a retention pond. This pond will settle out debris and sediment. Principle 8: Design sustainable facilities that can be safely maintained. RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Inlets and piping will be vacuumed or flushed periodically to maintain adequate flow. Proper grading reduces dangerous slopes and proper drainage reduces ice buildup. All facilities are easily accessible and are installed with cleanouts when applicable. Principle 9: Design and maintain facilities with public safety in mind. This system has been designed to mitigate 100-year events and covey them safely to the appropriate paths without impacting neighboring structures or properties. 4.0 Onsite Drainage The onsite drainage was also analyzed to satisfy the City of Aspen's urban Runoff Management Plan and grading and drainage requirements. 4.1 Drainage Basins Two drainage basins were delineated for the site. The West basin includes the lower patio and the western half of the roof area. The east basin contains the driveway and the easter portion of the structures roof. These areas are collected via roof drains and inlets and piped to one of two points of concentration at the retention pond on the southwest side of the property. Below is a summary of each basin and their respective impervious area ratios. Basin# Total Area Impervious Area Impervious (ft2) (ft2) EAST 8507.00 4673.00 54.93% WEST 9364.00 4897.00 52.30% 4.2 Peak Discharge Calculations The peak flows were calculated for the Major Basins 100-year storm events using the Rational Method. The Rational Method is an acceptable method to calculate runoff for this basin as the area is under 90 acres. Rainfall intensity was calculated using a Time of Concentration(Td) of 5 minutes. The actual time of concentration for this site is less than 5 minutes,but according to the City of Aspen URMP, equations used to calculate rainfall intensity are only valid for a time of concentration of 5 minutes or greater so the smallest valid time of concentration value was used. The 1-hour Rainfall depths (Pi)used for these calculations was taken from Table 2.2 of the URMP and is equal to 0.64 inches for the 5-year event and 1.23 inches for the 100-year event. Equation 2.1 was referenced when solving for the Rainfall Intensity (I). 88.8 P1 I (10 + Td)i.osz (Equation 2.1) Runoff Coefficients(C), a function of the Soil Group (in this case B for the onsite basin)and the percentage of impervious area within each sub basin were developed using Figure 3.3. The Runoff Coefficient(C)was then multiplied by the Rainfall Intensity(I)and the area of the Major Basin(A, in acres)to determine the peak discharge. Qp = CIA RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Qp = Peak Discharge (cfs) C = Runoff Coefficient I = Rainfall Intensity (inches per hour) A = Area (acres) These peak flow values were used to calculate the size of the proposed detention and conveyance structures, such as swales, drywells, inlets and pipes. The table below contains the peak flows for developed and undeveloped conditions for the 100-year storm event. 100 Year Peak Discharge Developed Calculations 1 Hour(P1) 1.23 Return Period 100 Basin ID Total Area Imp.Area Impervious C Value Time of C Intensity Q Max See(D1) (ft2) (ft2) (%) From Table (Td) I=88.8Pl/(10+Td)1.°52 (ft3/sec) EAST 8507.00 4673.00 54.93% 0.520 5 6.33 0.64 WEST 9364.00 4897.00 52.30% 0.520 5 6.33 0.71 100 Year Peak Discharge Pre Development Calculations 1 Hour(P1) 1.23 Return Period 100 Basin ID Total Area Imp.Area Impervious C Value Time of C Intensity Q Max See(D1) (ft2) (ft2) (%) From Table (Td) 1=88.8P1/(10+Td)1.°52 (ft3/sec) EAST 8507.00 0.00 0.00% 0.350 5 6.33 0.43 WEST 9364.00 0.00 0.00% 0.350 5 6.33 0.48 The max allowable discharge for the site shall be the sum of these two basins. In this case 0.91 cfs. 4.3 Historic Release When the pond is full to the over flow rim there will be 4.66 feet of head on the 4"diameter drain at the bottom of the pond. An orifice calculation was performed on this pipe to determine the flow through this pipe when the pond is full. Equation 4-19 from the City of Aspen Urban Runoff Management Plan was used. �� Perforation Orifice Calc Q=Flow Rate 0.89 cfs Ca=Discharge Coeff. (square) 0.6 A=Area of Orifice 0.086 ft2 H= Effective Head 4.66 ft g= Gray Const. 32.2 ft/sec2 Orifice Diameter 0.33 ft Orifice Diameter 3.96 in RECEIVED 688 Spruce St. 0 3/11/2 0 21 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT The 4-inch drain 4.66 feet down at the bottom of the pond will restrict the outflow to a max of 0.89 cfs when the pond is full. This satisfies the allowable historical release of 0.91 cfs. 5.0 Hydrological Criteria 5.1 Storm Recurrence and Rainfall The property is located outside of the commercial core and isn't served by any storm system so this property classifies as a"Sub-urban area not served by public storm sewer". Therefore,the storm system for the site was designed to meet detention requirements for the 5 and 100-year historical storm events. The 1-hour Rainfall depth(Pi) is given in Table 2.2 as 0.64 inches for the 5-year event and 1.23 inches for the 100-year event. The Intensity in inches per hour for different storm duration(Td)was calculated using Equation 2.1 from the City of Aspen URMP. 5.2 Storage Volumes Methodology The storage requirements for this site were calculated using the total impervious area along with the historic and developed peak runoff rates that were established in section 2.2. The proposed storm drainage system is designed for full detention of a 100-year storm event. The below tables summarize these calculations. Full Detention Storage Basin Total Area Impervious Area Impervious Full Detention Depth Factor of Safety Required Storage BMP (ft2) (ft2) (%) (in) F.O.S. (ft3) EAST 8507.00 4673.00 54.93% 1.23 1 479 Retention Pond WEST 9364.00 4897.00 52.30% 1.23 1 502 Retention Pond A retention pond has been proposed to provide this storage volume. The total required storage for the retention pond is 981 cf. Auto-CAD Civil 3D grading tools and analysis was used to determine the pond volume. Below is the Cut/Fill Report for the Pond. The reason total detention was used is because the downstream culvert was maxed out by the offsite drainage flowing through the site. RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Volume Summary Dame Type Cut Fill 2d Area Cut Fill Net Factor Factor (Sq.Ft.) (Cu.Yd.) (Cu.Yd.) (Cu_Yd.) POND full 1.000 1.000 1389.56 3.57 45.39 41.82 FiII: VOL_ Totals 2d Area Cut Fill Net (Sq.Ft.) (Cu_Yd.) (Cu_Yd.) (Cu_Yd.) Total 1389.56 3.57 45.39 41.82<=Fill> Value adjusted by cut or fill factor other than 1.0 The analytical tool determined the pond has 45.39 cubic yards of storage which equates to 1225.5 cubic feet. This satisfies the required 981 cubic feet. 6.0 Hydraulic Criteria 6.1 Piping These 100-year peak flows were then used to determine the storm pipe sizing. Pipe sizes were tested for hydraulic capacity at 80%of their full flowrate. Design charts giving Q design/Q full were downloaded from FHWA and the equations in Section 4.8.4 were used as the basis for these calculations. Calculated pipe sizes and depth of flow for onsite pipes are shown below. The capacity is also tested at the minimum of a 2% slope. It was determined that a 6-inch pipe sloped at 2.00%can convey the peak flows from each basin. Hydraulic Grade Line and Pipe Capacity Design Flow Proposed Pipe 80%of Proposed Manning Full Pipe Cross Q Design/ Hydraulic Grade Line Depth of Flow Less Than Basin Rate Diameter Slope Pipe Diameter Coefficient Sectional Area Full Pipe Flow Rate Q Full d/D (Depth of Flow) 80%of Pipe Diameter Qd.s(ftt/sec) Dpr,(in) S(%) Da*.8(in) n A(ft)=n(Dps,/2)' Qna(ftt/s)=A(1.49/n)((Dp.,/48)24)S42 Qa.,/Qra (from Chart) d(in)=(d/D)*Da, (Yes/No) East 0.64 6.0 2.00% 4.8 0.01 0.196 1.034 0.62 0.63 3.78 Yes West 0.71 6.0 2.00% 4.8 0.01 0.196 1.034 0.69 0.68 4.05 Yes 6.2 Inlets Inlets were also tested for capacity. Sub-basins were delineated to analyses individual inlets around the property. Below is a summary of those inlets and their individual 100-year peak flows. RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT 100 Year Sub Basin Peak Discharge Developed Calculations 1 Hour(Pi) 1.23 Return Period 100 Sub Basin Total Area Imp.Area Impervious C Value Time of C Intensity Sub Basin Flow Rate (Name) At(ft2) Ai(ft2) A•JAt(%) From Table (Td) I=88.8P1/(1O+Td)o1.D52 Qsub(ft3/sec) WO 228 228 100.00% 0.950 4 6.80 0.03 W1 1338 1338 100.00% 0.950 5 6.33 0.18 W2 353 353 100.00% 0.950 5 6.33 0.05 W3 279 279 100.00% 0.950 5 6.33 0.04 W4 350 350 100.00% 0.950 5 6.33 0.05 W5 990 990 100.00% 0.950 5 6.33 0.14 W6 879 879 100.00% 0.950 5 6.33 0.12 W7 142 142 100.00% 0.950 6 5.91 0.02 El 535 535 100.00% 0.950 5 6.33 0.07 E2 173 173 100.00% 0.950 5 6.33 0.02 E3 1587 85 5.36% 0.380 5 6.33 0.09 E4 752 597 79.39% 0.650 5 6.33 0.07 E5 1175 0 0.00% 0.350 5 6.33 0.06 E6 562 210 37.37% 0.490 5 6.33 0.04 E7 1994 1288 64.59% 0.570 5 6.33 0.17 E8 217 120 55.30% 0.540 5 6.33 0.02 E9 561 561 100.00% 0.950 5 6.33 0.08 E1O 655 655 100.00% 0.950 5 6.33 0.09 Each inlet was sized to accommodate the flows form their respective basins. Sub Basin and Circular Inlet Calculations 1 HOur(P,) 1.23 m=40% Y,=(Inlet Depression) Return Period 100 Cc=50% Co 0.65 Inlet ID Basin ID Total Area Imp.Area Impervious C Value Time of Concentration Intensity Q Max Inlet Type Diameter Effective Open Area(EQ.4-20) Inlet Depression Inlet Capacity(EQ4-19) Has Capacity See(D1) (ft) (ft') (%) From Table (Ta) 1=88.8P,/(10,Tu)co ftc/sec W.(Inches) Ac=(1-Cc)mA Ys=(ft) Q=CaA42gY, (Yes/No) WO WO 228 228 100.00% 0.950 5 6.33 0.031 8"Round 8 0.070 0.08 0.103 Yes W1 W1 1338 1338 100.00% 0.950 5 6.33 0.185 12"Round 12 0.157 0.20 0.366 Yes W2 W2 353 353 100.00% 0.950 5 6.33 0.049 8"Round 8 0.070 0.08 0.103 Yes W3 W3 279 279 100.00% 0.950 5 6.33 0.038 8"Round 8 0.070 0.08 0.103 Yes W4 W4 350 350 100.00% 0.950 5 6.33 0.048 8"Round 8 0.070 0.08 0.103 Yes W5 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A W7 W7 142 142 100.00% 0.950 5 6.33 0.020 8"Round 8 0.070 0.20 0.080 Yes El El 535 535 100.00% 0.950 5 6.33 0.074 8"Round 8 0.070 0.08 0.080 Yes E2 E2 173 173 100.00% 0.950 5 6.33 0.024 4"Round 4 0.017 0.08 0.080 Yes E3 E3 1587 85 5.36% 0.380 5 6.33 0.088 8"Round 8 0.070 0.08 0.200 Yes E4 E4 752 597 79.39% 0.650 5 6.33 0.071 8"Round 8 0.070 0.08 0.080 Yes E5 E5 1175 0 0.00% 0.350 5 6.33 0.060 8"Round 8 0.070 0.08 0.080 Yes E6 E6 562 210 37.37% 0.490 5 6.33 0.040 8"Round 8 0.070 0.08 0.080 Yes E7 E7 1994 1288 64.59% 0.570 5 6.33 0.165 12"Round 12 0.157 0.08 0.200 Yes E8 E8 217 120 55.30% 0.540 5 6.33 0.017 8"Round 8 0.070 0.08 0.080 Yes E9 E9 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A All inlets have capacity to capture the 100-year flow from their contributing basins. 7.0 Maintenance 7.1 City of Aspen Inlets within Right of Way The curb and gutter and inlets within the Spruce St. right of way shall be maintained by the City of Aspen. They are easily accessed off of Spruce St. The property owner shall not be responsible for the maintenance of these inlets and piping. RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT 7.2 Onsite Inlets and Piping- Continuation of the City of Aspen System The portion of the City of Aspen storm system that extends onto the property from Spruce St. shall be maintained by the property owner. Inlets, piping and manholes must be inspected and maintained quarterly and after every storm exceeding 0.5 inches.All sediment and debris that has entered the system must be removed. Dispose of sediment, debris, and any other waste material removed from the inlets. Inspect for any damage to the system, and replace or repair as necessary to prevent further deterioration. Inspect all grouted seams and cracks. If cracks are smaller than 'h", record information and continue inspection regularly. If cracks are larger than 'A", re-grout and repair to prevent further damage. Report all settling and deteriorating conditions to the infrastructure. The system is accessible from Spruce St. if a vacuum truck is necessary. A hydro vac service was contacted to ensure the remote hose length could reach the bottom basin. The company informed me they have a 4-inch hose that is 300' long that could service al the inlets. An agreement will be signed 7.3 Trench Drains Trench drains must be regularly inspected and maintained to prevent clogging and debris from travelling further into the system. Routinely keep drain grates and surrounding patios clean and free of leaves, dirt, and other debris. This will prevent clogging and damage to the storm infrastructure. Inspect drain sumps quarterly and after every storm exceeding 0.5 inches, remove excess sediment and debris buildup from the catch basin. Inspect system for damage to the concrete and the grate. Inspect all grouted seams and cracks. If cracks are smaller than %",record information and continue inspection regularly. If cracks are larger than 'A", re-grout and repair to prevent further damage. If grate is damaged, repair or replace as necessary. 7.4 Retention Pond The pond shall be routinely inspected for visible sediment and debris. If excess sediment or debris builds up,the ponds shall be cleaned with the outlet structure inspected and vacuumed of flushed if necessary. Sediment build-up may require periodic removal of sediments and plants when clogging reduces infiltration capacity to unacceptable levels. Access to facility must be provided to enable maintenance operations. Plant materials in areas prone to sediment build-up should be limited to grasses and groundcovers tolerant of periodic wet-dry cycles. Below is the recommendations for maintaince. RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Required Action Maintenance Objectives Frequency Inspections Inspect detention area to determine if Routine—Annual inspection of the sandy growth media is allowing hydraulic performance. acceptable infiltration. Lawn mowing and vegetative care Occasional mowing of grasses and Routine—Depending on aesthetic weed removal to limit unwanted requirements. vegetation. Maintain irrigated turf grass as 2 to 4 inches tall and non- irrigated native turf grasses at 4 to 6 inches. Debris and litter removal Remove debris and litter from Routine—Depending on aesthetic detention area to minimize clogging requirements. of the sand media. Landscaping removal and The sandy loam turf and landscaping Every 5 to 15 years, depending on replacement layer will clog with time as materials infiltration rates needed to drain the accumulate on it.This layer will need WQCV in 12-hours or less. May to be removed and replaced to need to do it more frequently if rehabilitate infiltration rates,along exfiltration rates are too low to with all turf and other vegetation achieve this goal. growing on the surface. An agreement will be signed between the property owner and the City. RECEIVED 688 Spruce St. 0 3/11/2 0 21 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Appendix A - Site Location and Offsite Point of Concentration Photos RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT 688 Spruce St. ® +� '} «at 1 „ f ►, >< ; Legend k }} .=', ft. *ii f' it s. Offsite drainge �.. • Y. t y Y r9 L f4je , '�;� �, t • lt��� :y { : . Point of Concentration "` ,¢ , ' : fi ..-, , :.i Y ,,? f 6. ar i r. .,. , l i.�jl.. "it,S 4",0:a.+T ,! � iR'. - [11: 7 O,t f �Y: .j ' of f ,..,ii J ✓ 'ga m ✓,J H.�, � x• Y. Z;k ,Res '+► , f • ^' i `,. -4 •� f ,y. .'t _ 1'\< . d' .." aT6 xll�' i t . gF • 4 .z',f . '• ..1 SSA s . ,7 •y . t• A• * }`a • R ' )(1..4 ...�''� !�-3` . F. ' t J�`f. L'a3 yam . T '�, s. lines Flow �'" n. ..mow: �:` !T *, , ,.}CY. 4""� � .. F w it, . North Driveway tom' ' Entrance ; u Y::..:�ij ;� }_ yy 688 Spruce St. ir. �" '4: : 1: 1:rtt; z it a l _ Residence If !3 s ,...-: • Offsite Point of `` b e � Y, i,r `S i�t ' `, " . - Concentration 4t I ;_, ir .... .41 iti ' .' fli*ill . . : 1 r N4 i South Driveway t �� �� �µ. ils. • 1111r,Ciiiti ryx ..J '. •. I• 9 �� 1,. iY1 f . ` Entrance �' =.,iE �`' iii: ,, 1,- .., y-iVo 4! ,_ . ',,; - N., _ -....i.,__. ,\It,._ ,.., y -__ luy�r' . '-liv ... ..., 1._ 1 A' 11F . ,,, coi-iii .. 4 s� rC bogie Earth , j - ,.. P T ,L l,� a i N , .sue �, *, , �% ,;. •:• . . n t ' • 8 A _ ,r-. ` .y 400 ft e 9r�,g,eoogle -. a �� • �. , r 1 1 1 1 -1- T 688 Spruce St. Legend -Offsite Ponit of Concentration Y;�'iv,,^ ;�"' -Northern driveway entrance �<' �� '''3►,.�s%"' -Facing due west t fL �. : < - , • y y •` il..J�}., ,.A,.i-• fi=. l `v ?` • , '.14•'h_, _ h •, .i, �,4' _ , , ♦ + � ... ),. _ , / Imo ��, • mot( 1 ✓.?/,�'•`, 'f' .. .* v; , 1f ) I i • ,�. , . • • ` 4.I - Offsite Point of ` ,_. .. , , f',- 1 , • .. :' Concentration 1 - • ~�"'"-i2- is v a%. '' "�1 _y ^t 5.: ' 1 f 1 • •. 1001 1 .�!r } .. IJ y Z i�,�1�,,'y�. ��'`+'i •'�� d 1f� j► '., .• / t :• • • v,; - ,'r'I 'f !�,[•,om • „ S'.. „'r +., ,;. �y _ �: . ",. 688 Spruce St. -'r Neighboring ' • ,'� ` '�-�' ,-_ , . North Entrance driveway to the ..'- -. •-- . . a= - ._ • north 40 --�. ,,'r- .c -jam _ • . rr--t Spruce St. -� --continues to the south . .. 1:- - • , _ - Offsite flow line • 1 r ;�" Spruce St. -from uphill basin 1 f "/ continues east • _J,, r. „_, _ ' - uphill • . REEIVEC Google Earth ' - 1 63. g1�1.03/llg 20'I8�oogl _" - r Appendix B - The Smuggler/Hunter Surface Drainage Master Plan Hunter Creek Basin Delineation RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT °� ,! °, SITE-688 SPRUCE ST. �l ,9aoo ° • 1 1pp0 jo+p0�.... ...�., Sal ���4h°n /� pm. �ssoo Pit HUNTER CREEK N -� �9aa J BASIN „� --\-\---,-\-N\Thru—'*:i- o Hunter Creek Basin ; 45-), atitteEtalta w Z '��tt_ 1 ^� a g ke �` l i I s•%•'\,_` , a . �' D•- (' r oy T• -r--------2, I; S Gibson Avenue Basin SPRUCE ST. °/ VINES litialhi. 11,'""-'"' . p FRa via \ �� I . ,_x--- 1111rAW- tarot .Th Gibson Ave�I —••,•. MockZin1, f'� �� *Johnson Shaft �� °obi AspenA Museum Park ^° oligilir _ Ai W • Neale Avenue and OK Flats Basin ` gamr ,... � HAL,arisr , O � '� ,41 °9 �� �` it N 111111111111011 KER 3T RIO GRAN.P ` ��s °�� OOp` . i ma g o 'soo V Spring Strtior .�� yL ti -pe5 II LOP; \ / hirp.4111111r iN ST V , .....,‘ � s -MollieGibson'ShaftNsgv�� ?1) �St P5� 7• Unknown Source-. • t(olipacg L'iHerron-Park Belk*-' 40 . ri �Q Garrison Park G to u� or�n m kR'ver, MASc�,,,,N .,,, 'o\ Stillwater Bridge Basin IN/ W.* 6 air ofDu ' r Riverside McSkimming Basin O atir Tq�E if* Eco•, ,a Snyder o� •• I Eastwood Basin 73 s Park p 0 co 0 i l''' iEl gfi I sr--- ?� asft; Q J N�""G\ I a ,-f-' co # :11, E ci 111011 lob \!,• m Q ti ,c GTs '°o, `'' _ ry °o\ V^ L0RI tEJ� o IPo� TEP WESTVI: DR = I4o. azoo �? • ° �� O I LL aaoo °po • $° ill - „•:: i• 2 Ili 110. O ° Nil" STALLA •i - aaoo <G �G I° aaoo 7/ �� • I t j-- .---.1. 300 .: O 13 122o ,,, 1\ 1 m $ t e eyoO ° 0 =4 . 0 00 I/ \ 8600 me °soo °4Oo • Ale TIN w• I. moo Ln (�a7oa o°SoN, o°o aaoo ° jr o g9p048B0pL........N.:34r Q- \filiSlik i e '41 000 \ ,e 0 Q 0 Legend ol SMUGGLER/HUNTER SURFACE Mine Flow Sources Wetland Areas Major Basins DRAINAGE MASTER PLAN _ Eastwood Basin N El Potential Water Quality Locationsgl Riparian Areas _ Gibson Avenue Basin e • Irrigation Ditch,Culvert I Surface Water Hunter Creek Basin a THE CITY OF ASPEN — — Irrigation Ditch,Open Neale Avenue and OK Flats Basin o too eet MAJOR Y1G EEIVE C a Riverside McSkimming Basin AREA MAP Topographic Contour (feet NGVD29) .'' URS 1..�.r LI`J Stillwater Bridge Basin 0 3/11/2 0 21 I Study Area Boundary ASUFL ISM..2 a r BUILDING DEPARTMENT Appendix C - Hunter Creek Sub-Basin Delineations and Point of Concentration Locations RECEIVED 688 Spruce St. 0 3/11/2 0 21 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT 00r t,._ — l Legend 11P10111 1 ® Potential Water Quality Locations �•. Topographic Contour • Interval=10 feet • �� Irrigation Ditch,Culvert \ —•••—•• Irrigation Ditch,Open Qk`.k - I. _• I:::: Boundary — = Major Basins \�J Wetland Areas ii, ; ; .:: I Riparian Areas Surface Water \ InfoSWMM Elements ç • Junction H02c141 Q Divider , Ci , ... -i� .--". ■ Outfall o4ftrSUB-BASINH01 P. _ IOW ��0 y" �� j OFALL• _.11 SITE-688 SPRUCE ST. . H01 110 o� s �N Hunter Creek Basin �Qek N H0� _1 ��� t _... H01 P oFAu-12 Hunter Creek Basin a E L, _ - NCO o H05 •., )0 \ z CLI 1,0 - o 3 z , I 1 . I le M "� .141110/ril . i ��% �. m oDA- `'. 0 200 2 R4.....i Feet 15, •� � / �� TILLIAMS WAY o _ s o • 7 �- CL Hos SPRUCE ST. << I '� �5 V I12, r \ THE CITY OF ASPEN �J , ) a \ , UM Tt. 1\,_ / ool I °' ,\ 4�I Gibson Ave` "�'" _ U SMUGGLER HUNTER SURFACE to is Z ra 9L6' w F Z DRAINAGE MASTER PLAN E —... p U Z 1 Z Z w Z �I G-0 2 ....� m o DRAINAGE n 1. N � ao 11 z SWMM ROUTI r8�5 �� w 5 20 o HUNTER CREEKS BASIN 21 N� / Aspen ArfMuseum Park N� WALNUT ST U U PAGE 1 / 0 .�. / _ � \ ix ASP N3 BUILDING DEPARTM T Appendix D - Curb and Gutter Hydraulics RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Wednesday,Jan 6 2021 Appendix D - C&G Capacity 8.8 cfs Gutter Highlighted Cross SI, Sx (ft/ft) = 0.020 Depth (ft) = 0.34 Cross SI, Sw (ft/ft) = 0.083 Q (cfs) = 8.800 Gutter Width (ft) = 2.00 Area (sqft) = 1.27 Invert Elev (ft) = 100.00 Velocity (ft/s) = 6.96 Slope (%) = 4.00 Wetted Perim (ft) = 11.02 N-Value = 0.013 Crit Depth, Yc (ft) = 0.50 Spread Width (ft) = 10.67 Calculations EGL (ft) = 1.09 Compute by: Known Q Known Q (cfs) = 8.80 Elev (ft) Section Depth (ft) 101.00 1.00 100.75 0.75 100.50 0.50 100.25 0.25 100.00 0.00 99.75 R E C E_IO2 D 0 2 4 6 8 10 12 14 16 18 20 22 24 03/ 1/2021 Reach (ft) ASPEN BUILDING DEPARTMENT Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Monday,Jan 18 2021 Driveway Entrance Swale - 8.8cfs User-defined Highlighted Invert Elev (ft) = 7971.01 Depth (ft) = 0.28 Slope (%) = 8.64 Q (cfs) = 8.800 N-Value = 0.013 Area (sqft) = 1.17 Velocity (ft/s) = 7.53 Calculations Wetted Perim (ft) = 10.04 Compute by: Known Q Crit Depth, Yc (ft) = 0.45 Known Q (cfs) = 8.80 Top Width (ft) = 10.03 EGL (ft) = 1.16 (Sta, El, n)-(Sta, El, n)... (6.21,7971.34)-(10.94,7971.14,0.013)-(12.44,7971.01,0.013)-(13.94,7971.14,0.013)-(21.87,7971.48,0.013) Elev (ft) Section Depth (ft) 7972.00 0.99 7.71.75 0.74 7471.50 0.49 7.71.25 - 0.24 7.71.00 -0.01 7.70.75 RECELD 2 4 6 8 10 12 14 16 18 20 22 4 03/211/2021 Sta (ft) ASPEN BUILDING DEPARTMENT Appendix E - Storm Inlet Hydraulic Capacities RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Wednesday,Jan 6 2021 Curb Inlet-3 - 2.99 CFS Grate Inlet Calculations Location = On grade Compute by: Known Q Curb Length (ft) = -0- Q (cfs) = 2.99 Throat Height (in) = -0- Grate Area (sqft) = -0- Highlighted Grate Width (ft) = 1.36 Q Total (cfs) = 2.99 Grate Length (ft) = 2.45 Q Capt (cfs) = 1.67 Q Bypass (cfs) = 1.32 Gutter Depth at Inlet (in) = 2.39 Slope, Sw (ft/ft) = 0.050 Efficiency (%) = 56 Slope, Sx (ft/ft) = 0.020 Gutter Spread (ft) = 6.55 Local Depr (in) = 0.10 Gutter Vel (ft/s) = 6.12 Gutter Width (ft) = 2.00 Bypass Spread (ft) = 4.35 Gutter Slope (%) = 8.58 Bypass Depth (in) = 1.76 Gutter n-value = 0.016 All dimensions in feet 2.0 4.55 RECEIVED 03/11/2021 ASPEN BUILDING DEPARTMENT Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Wednesday,Jan 6 2021 Curb Inlet-2 - 5.46 CFS Grate Inlet Calculations Location = On grade Compute by: Known Q Curb Length (ft) = -0- Q (cfs) = 5.46 Throat Height (in) = -0- Grate Area (sqft) = -0- Highlighted Grate Width (ft) = 1.36 Q Total (cfs) = 5.46 Grate Length (ft) = 2.45 Q Capt (cfs) = 2.47 Q Bypass (cfs) = 2.99 Gutter Depth at Inlet (in) = 2.87 Slope, Sw (ft/ft) = 0.050 Efficiency (%) = 45 Slope, Sx (ft/ft) = 0.020 Gutter Spread (ft) = 8.54 Local Depr (in) = 0.10 Gutter Vel (ft/s) = 6.92 Gutter Width (ft) = 2.00 Bypass Spread (ft) = 6.55 Gutter Slope (%) = 8.58 Bypass Depth (in) = 2.29 Gutter n-value = 0.016 All dimensions in feet Al01111111111111.111 -02.0 6M C RECEIVED 03/11/2021 ASPEN BUILDING DEPARTMENT Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Wednesday,Jan 6 2021 Curb Inlet-1 - 8.8 CFS Grate Inlet Calculations Location = On grade Compute by: Known Q Curb Length (ft) = -0- Q (cfs) = 8.80 Throat Height (in) = -0- Grate Area (sqft) = -0- Highlighted Grate Width (ft) = 1.36 Q Total (cfs) = 8.80 Grate Length (ft) = 2.45 Q Capt (cfs) = 3.34 Q Bypass (cfs) = 5.46 Gutter Depth at Inlet (in) = 3.32 Slope, Sw (ft/ft) = 0.050 Efficiency (%) = 38 Slope, Sx (ft/ft) = 0.020 Gutter Spread (ft) = 10.42 Local Depr (in) = 0.10 Gutter Vel (ft/s) = 7.68 Gutter Width (ft) = 2.00 Bypass Spread (ft) = 8.54 Gutter Slope (%) = 8.58 Bypass Depth (in) = 2.77 Gutter n-value = 0.016 All dimensions in feet C28 • 8.42 �— RECEIVED 03/11/2021 ASPEN BUILDING DEPARTMENT Appendix F - 18-inch Concrete Culvert Hydraulics RECEIVED 688SpruceSt. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Culvert Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Wednesday,Sep 30 2020 18in Concrete Pipe - Slope=2% Invert Elev Dn (ft) = 100.00 Calculations Pipe Length (ft) = 30.00 Qmin (cfs) = 0.00 Slope (%) = 2.00 Qmax (cfs) = 8.00 Invert Elev Up (ft) = 100.60 Tailwater Elev (ft) = (dc+D)/2 Rise (in) = 18.0 Shape = Circular Highlighted Span (in) = 18.0 Qtotal (cfs) = 8.00 No. Barrels = 1 Qpipe (cfs) = 8.00 n-Value = 0.012 Qovertop (cfs) = 0.00 Culvert Type = Circular Concrete Veloc Dn (ft/s) = 4.92 Culvert Entrance = Square edge w/headwall (C) Veloc Up (ft/s) = 5.79 Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 HGL Dn (ft) = 101.30 HGL Up (ft) = 101.69 Embankment Hw Elev (ft) = 102.41 Top Elevation (ft) = 105.00 Hw/D (ft) = 1.20 Top Width (ft) = 25.00 Flow Regime = Inlet Control Crest Width (ft) = 25.00 Elea(ft) 18in Concrete Pipe-Slope=2% Hw Depth(It) 106.00 5.40 106.00 4.40 104.00 3.40 103.00 2.40 co..b d 102.00 1.40 101.00 0.40 100.00 -0.60 99.00 -1.60 0 5 10 15 20 25 30 35 40 45 50 Circular Culvert HGL Embank Reach(ft) RECEIVED 03/11/2021 ASPEN BUILDING DEPARTMENT Appendix G - Soils Report RECEIVED 688 Spruce St. 03/11/2021 Preliminary Engineering Report ASPEN BUILDING DEPARTMENT Kumar&Associates,Inc.. Geotechnical and Materials Engineers 5020 County Road 154 and Environmental Scientists Glenwood Springs,CO 81601 ——`� phone:(970)945-7988 fax:(970)945-8454 email:kaglenwood@kumarusa.com An Employee Owned Company www.kumarusa.com Office Locations: Denver(HQ),Parker,Colorado Springs,Fort Collins,Glenwood Springs,and Summit County,Colorado cots&Associates 4c 33/Qiztiace, www.komarusa.mm 19g9_Zp19 SUBSOIL STUDY FOR FOUNDATION DESIGN PROPOSED RESIDENCE 688 SPRUCE STREET ASPEN, COLORADO PROJECT NO. 19-7-488 SEPTEMBER 27, 2019 PREPARED FOR: MKMN, LLC ATTN: JEN & GREG GOLDFARB 800 MAGNOLIA STREET MENLO PARK, CALIFORNIA 94025 mkmnllc(a gmail.com _ 03/11/2021 ASPEN BUILDING DEPARTMENT TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY - 1 - PROPOSED CONSTRUCTION - 1 - SITE CONDITIONS - 1 - FIELD EXPLORATION -2 - SUBSURFACE CONDITIONS - 2 - DESIGN RECOMMENDATIONS - 3 - FOUNDATIONS - 3 - FOUNDATION AND RETAINING WALLS - 4 - FLOOR SLABS - 5 - UNDERDRAIN SYSTEM - 5 - SITE GRADING - 6 - SURFACE DRAINAGE - 6 - LIMITATIONS - 7 - FIGURE 1 - LOCATION OF EXPLORATORY BORINGS FIGURE 2 - LOGS OF EXPLORATORY BORINGS FIGURE 3 - LEGEND AND NOTES FIGURES 4 AND 5- GRADATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS TABLE 2-PERCOLATION TEST RESULTS RECEIVED 03/1 1 /2021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT PURPOSE AND SCOPE OF STUDY This report presents the results of a subsoil study for a proposed residence to be located at 688 Spruce Street, Aspen, Colorado. The project site is shown on Figure 1. The purpose of the study was to develop recommendations for the foundation design. The study was conducted in accordance with our proposal for geotechnical engineering services to MKMN, LLC dated May 21, 2019. A field exploration program consisting of exploratory borings was conducted to obtain information on the subsurface conditions. Samples of the subsoils obtained during the field exploration were tested in the laboratory to determine their classification and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for foundation types, depths and allowable pressures for the proposed building foundation. This report summarizes the data obtained during this study and presents our conclusions, design recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. PROPOSED CONSTRUCTION The existing house will be razed. The proposed residence will be a two-story structure over a full basement level. Basement and attached garage floors will be slab-on-grade. Grading for the structure is assumed to be involve cut depths between about 4 to 12 feet. We assume relatively light foundation loadings,typical of the proposed type of construction. If building loadings, location or grading plans change significantly from those described above, we should be notified to re-evaluate the recommendations contained in this report. SITE CONDITIONS The site is currently occupied by an existing residence with asphalt and concrete driveway. In general, the site slopes down to the west at between 5 and 20%. There are steeper slopes approaching 50%in the southwest corner of the property. Vegetation consists of landscaped RECEIVED 03/11/2021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT -2 - lawn, shrubs and aspen trees and junipers. The lower southwest part of the property appears to contain relatively deep fill from past grading. FIELD EXPLORATION The field exploration for the project was conducted on September 3, 2019. Three exploratory borings were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions. The borings were advanced with 4 inch diameter continuous flight augers powered by a truck- mounted CME-45B drill rig. The borings were logged by a representative of Kumar& Associates, Inc. Samples of the subsoils were taken with a 1%inch I.D. spoon sampler. The sampler was driven into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM Method D-1586. The penetration resistance values are an indication of the relative density of the subsoils. Depths at which the samples were taken and the penetration resistance values are shown on the Logs of Exploratory Borings, Figure 2. The samples were returned to our laboratory for review by the project engineer and testing. SUBSURFACE CONDITIONS Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. The subsoils, below 3% feet of sand and gravel fill in Boring 1 or 1 to 1% feet of topsoil in Borings 2 and 3, consist of up to 20 feet of medium dense silty sand and gravel with cobbles and possible boulders. A loose sand layer was encountered below about 15 feet in Boring 3. Drilling in the coarse granular soils with auger equipment was difficult due to the cobbles and boulders and drilling refusal was encountered in the deposit at Boring 1 located on the upper bench of the site. Laboratory testing performed on samples obtained from the borings included natural moisture content and gradation analyses. Results of gradation analyses performed on small diameter drive samples (minus 1%-inch fraction) of the coarse granular subsoils are shown on Figures 4 and 5. Shallow samples of the sand and gravel soils from Borings 2 and 3 were taken for total lead RECEIVED 03/11/2_021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT - 3 - testing. The lead testing results will be provided separately. The laboratory testing is summarized in Table 1. No free water was encountered in the borings at the time of drilling and the subsoils were slightly moist to moist. DESIGN RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratory borings and the nature of the proposed construction,we recommend the building be founded with spread footings bearing on the natural granular soils. The design and construction criteria presented below should be observed for a spread footing foundation system. 1) Footings placed on the undisturbed natural granular soils should be designed for an allowable bearing pressure of 2,000 psf. Based on experience, we expect settlement of footings designed and constructed as discussed in this section will be about 1 inch or less. 2) The footings should have a minimum width of 18 inches for continuous walls and 2 feet for isolated pads. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Placement of foundations at least 42 inches below exterior grade is typically used in this area. 4) Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least 10 feet. Foundation walls acting as retaining structures should also be designed to resist lateral earth pressures as discussed in the "Foundation and Retaining Walls" section of this report. 5) All existing fill, debris, topsoil and any loose or disturbed soils should be removed and the footing bearing level extended down to the relatively dens" ens r E 1VE D 03/11 /0021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT - 4- natural granular soils. The exposed soils in footing area should then be moistened and compacted. If water seepage is encountered, the footing areas should be dewatered before concrete placement. 6) A representative of the geotechnical engineer should observe all footing excavations prior to concrete placement to evaluate bearing conditions. FOUNDATION AND RETAINING WALLS Foundation walls and retaining structures which are laterally supported and can be expected to undergo only a slight amount of deflection should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 45 pcf for backfill consisting of the on-site granular soils. Cantilevered retaining structures which are separate from the residence and can be expected to deflect sufficiently to mobilize the full active earth pressure condition should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 40 pcf for backfill consisting of the on-site granular soils. All foundation and retaining structures should be designed for appropriate hydrostatic and surcharge pressures such as adjacent footings,traffic, construction materials and equipment. The pressures recommended above assume drained conditions behind the walls and a horizontal backfill surface. The buildup of water behind a wall or an upward sloping backfill surface will increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain should be provided to prevent hydrostatic pressure buildup behind walls. Backfill should be placed in uniform lifts and compacted to at least 90% of the maximum standard Proctor density at a moisture content near optimum. Backfill placed below pavement and walkway areas should be compacted to at least 95% of the maximum standard Proctor density. Care should be taken not to overcompact the backfill or use large equipment near the wall, since this could cause excessive lateral pressure on the wall. Some settlement of deep foundation wall backfill should be expected, even if the material is placed correctly, and could result in distress to facilities constructed on the backfill. Backfill should not contain organics, debris or rock larger than about 6 inches. The lateral resistance of foundation or retaining wall footings will be a combination of the ����� sliding resistance of the footing on the foundation materials and passive earth pressure aga 03/1 1 /2021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT - 5 - the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated based on a coefficient of friction of 0.45. Passive pressure of compacted backfill against the sides of the footings can be calculated using an equivalent fluid unit weight of 325 pcf. The coefficient of friction and passive pressure values recommended above assume ultimate soil strength. Suitable factors of safety should be included in the design to limit the strain which will occur at the ultimate strength,particularly in the case of passive resistance. Fill placed against the sides of the footings to resist lateral loads should be compacted to at least 95% of the maximum standard Proctor density at a moisture content near optimum. FLOOR SLABS The natural on-site granular soils, exclusive of topsoil, are suitable to support lightly loaded slab- on-grade construction. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minimum 4 inch layer of free- draining gravel should be placed beneath basement level slabs to facilitate drainage. This material should consist of minus 2-inch aggregate with at least 50%retained on the No. 4 sieve and less than 2%passing the No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 95% of maximum standard Proctor density at a moisture content near optimum. Required fill can consist of the on- site granular soils devoid of vegetation,topsoil and oversized rock. UNDERDRAIN SYSTEM Although free water was not encountered during our exploration, it has been our experience in mountainous areas that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can create a perched condition. We recommend below-grade construction, such as retaining walls, crawlspace and basement areas,be protected from wetting and hydrostatic pressure buildup by an underdrain system. RECEIVED 03/11/2021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT - 6 - The drains should consist of drainpipe placed in the bottom of the wall backfill surrounded above the invert level with free-draining granular material. The drain should be placed at each level of excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1%to a suitable gravity outlet. Free-draining granular material used in the underdrain system should contain less than 2%passing the No. 200 sieve, less than 50%passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at least 1%2 feet deep. SITE GRADING The risk of construction-induced slope instability at the site appears low provided the building is located away from the steep slope as planned and cut and fill depths are limited. We assume the cut depths for the basement level will not exceed one level, about 10 to 12 feet. Fills should be limited to about 8 to 10 feet deep, especially downhill of the residence where the slope steepens. Embankment fills should be compacted to at least 95% of the maximum standard Proctor density near optimum moisture content. Prior to fill placement,the subgrade should be carefully prepared by removing all vegetation and topsoil and compacting to at least 95% of the maximum standard Proctor density. The fill should be benched into the portions of the hillside exceeding 20% grade. Permanent unretained cut and fill slopes should be graded at 2 horizontal to 1 vertical or flatter and protected against erosion by revegetation or other means. The risk of slope instability will be increased if seepage is encountered in cuts and flatter slopes may be necessary. If seepage is encountered in permanent cuts, an investigation should be conducted to determine if the seepage will adversely affect the cut stability. This office should review site grading plans for the project prior to construction. SURFACE DRAINAGE The following drainage precautions should be observed during construction and maintained at all times after the residence has been completed: 1) Inundation of the foundation excavations and underslab areas should be avoided during construction. RECEIVES 03/11/2021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT - 7 - 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95% of the maximum standard Proctor density in pavement and slab areas and to at least 90% of the maximum standard Proctor density in landscape areas. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in paved areas. Free-draining wall backfill should be capped with about 2 feet of the on-site soils to reduce surface water infiltration. 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. LIMITATIONS This study has been conducted in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either express or implied. The conclusions and recommendations submitted in this report are based upon the data obtained from the exploratory borings drilled at the locations indicated on Figure 1,the proposed type of construction and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC,then a professional in this special field of practice should be consulted. Our findings include interpolation and extrapolation of the subsurface conditions identified at the exploratory borings and variations in the subsurface conditions may not become evident until excavation is performed. If conditions encountered during construction appear different from those described in this report, we should be notified so that re-evaluation of the recommendations may be made. This report has been prepared for the exclusive use by our client for design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves,we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation RECEIVED 03/11/2021 Kumar&Associates,Inc. Project No.19-7-488 ASPEN BUILDING DEPARTMENT - 8 - of excavations and foundation bearing strata and testing of structural fill by a representative of the geotechnical engineer. Respectfully Submitted, Kumar& Associates, In 2; Daniel E. Hardin, P. ° l 2/ 9 ;cc Reviewed by: --,0% `i 7 ,.....„_„.1.v._.,04. ._,........A..._ Steven L. Pawlak,P.E. DEH/kac cc: Phillip Ring phillip@rds-aspen.com RECEIVED 03/11/2021 Kumar&Associates,Inc.® Project No.19-7-488 ASPEN BUILDING DEPARTMENT \\ rS 1,3 GN'AIn BETT.I'N \ ,N WATERLINE O lar ONE FOUNDS BUM BRASS CAP LOT TwO Lfi aENARw,.2'Y. ,N P, SET IN Y}B AS ORIGINAL L \ _ YlOOPER SURDIVISIO'S \\ )IryPI w`PIASTICCA 13. ON CENTER q IOARTER CORNER R FENCE \ \_`/ pq BEARS C LAT BR K IR PLAT BR K PO NI GR UND U 2,1 SECTION 7. E DM S(SPYI IAL 1117.1 \\ \\ n] _ fP 148LM IT BRNS} D STANPND'SF ; _ ONSIU•ItN PIPF FOVn'D POUND 3 131.11LIA BRASS CA SECCENTER TIUN F-N SSV SVE t Iuu ; ' Nf ' I rc DF ILi TAG C 1 —I 9 / �, LAC ,.A k 3 I I !) I I I i ' I k rnE I,,'4 ' 1 "I'' . 1 Oq I SE B C L f.a. I I '�Ebq_ryIONE. I on (TIM, gI tr r .,M�' , f n I; I,e, 1 l ice. tc 1 "i_ , „ ., Il 1 �ry 1 » I .I f' .I„ . 'EE/' AO,lc1 �I t*'\ j D4 r "v R �1 f ', , ' F r fw 1 �, i + ter, II �t • i N� '80RING 2 a ,.L. :� : F { f,Wlll1t ,Y5,,. MULTILEVEL �W iLT1 n' �. ' z \;\ II 8 M1ti wll.f ,IXDD IMOn I n` I' /' ' V. A t fW] ° t- R ' I i I0 t LON n SIGYj ARMULDINO SETBACK '' / ` • I,.Y\, fx ff` LSS'UR FRRIsa • 1.219ACi. I.T / N ET gam w li 6RR SPRUCE STRFF.T BORING 3 ,t ""`" �•, `\\ WATER ! en sTREET TM Mr PURE lc RoAll PARKING fi I /J Apr I I I ,Al PR n I Ce `/ GL e' i j( i i, . R F A BR I a I I rve ,t�`'rv; 1 7 I i i I Y \ I (n • ILr i i . 7 I A „' < I f3; MF q: i DRI,wAA .R isi 1 o.LADw: ' `\ p AS RENAR• D M11) _ i. PLASTIC CAP ]. TxN>Y3 ,, LrE zo N.fr ' .., A r MOVE, M SSI )•O'19F 1 't a 1 L N' �r\ � 2 per— S T�If �,,-s .., a +.. i31 COA Os at nraas Bx„).0 nr Unlr] SMUGGLER HUNTER TRUST CONDOMINIUMS SVY'Pi'a IFN'S}4 f)' I I. IT- 5 PLAT RR Iw Pcu N 'sR Dg LNRI l fit. f __ ,_ .• , , o�NABDA.EG.S. o�� :�o., 1 BwARRR,LASTIC w EEP g'+`. rt i z e 8 2 1 8 e S F. 25 0 25 50 n, APPROXIMATE SCALE—FEETRErFivED 1 19-7-488 Kumar &Associates LOCATION OF EXPLORATORY BORINGS D}�Fig 021 iGr[N BUILDING DEPARTMENT BORING 1 BORING 2 BORING 3 EL. 7967' EL. 7954' EL. 7954' 0 ro 0 -ow., ti — 28/12 18/12 49/12 >I5° WC.. 6O 14/12 26/12 WC=5.3 — +4=20 `_ +4=26 5 31/12 —200=15 0.• 10/12 10/12 —200=12 5 WC=3.1 - — — —200=16 — — °( iii 10 48/12 27/12 10 F w— —w Law Fil w_ —w I 00WC=2.3 � I 1-— +4=38 —0 1- w 200=12 Ow o 15 I 57/12 5/12 15 WC=4.8 +4=90 —200=12 — 20 19/12 di 2/12 20 25 25 3 `I 1 Q z, v [n I E L' „; RECEIVE[ of o:CZ. 19-7-488 Kumar & Associates LOGS OF EXPLORATORY BORINGS 0 (112/2021 a9• "' ASPEN BUILDING DEPARTMENT LEGEND ��TOPSOIL; ORGANIC, SILTY SAND WITH SCATTERED GRAVEL, LOOSE TO MEDIUM DENSE, % ,SLIGHTLY MOIST, DARK BROWN. FILL: SILTY SAND AND GRAVEL, MEDIUM DENSE, SLIGHTLY MOIST TO MOIST, LIGHT BROWN AND GRAY. BORING 1 ONLY. 4 SAND AND GRAVEL (SM-GM); SILTY WITH COBBLES, LOOSE TO MEDIUM DENSE, SLIGHTLY 4. •-MOIST, LIGHT BROWN. o.-: 11 DRIVE SAMPLE, 1 3/8-INCH I.D. SPLIT SPOON STANDARD PENETRATION TEST. 28/12 DRIVE SAMPLE BLOW COUNT. INDICATES THAT 28 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE THE SAMPLER 12 INCHES. t PRACTICAL AUGER REFUSAL. NOTES 1. THE EXPLORATORY BORINGS WERE DRILLED ON SEPTEMBER 3, 2019 WITH A 4-INCH-DIAMETER CONTINUOUS-FLIGHT POWER AUGER. 2. THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED. 3. THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE OBTAINED BY INTERPOLATION BETWEEN CONTOURS ON THE SITE PLAN PROVIDED. 4. THE EXPLORATORY BORING LOCATIONS AND ELEVATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED. 5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING LOGS REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL. 6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORINGS AT THE TIME OF DRILLING. 7. LABORATORY TEST RESULTS: WC = WATER CONTENT (%) (ASTM D2216); +4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ASTM D6913); -200= PERCENTAGE PASSING NO. 200 SIEVE (ASTM D1140). , 1 �v1• I ‘1 '_ 1 I ,1 1 1 11 ,) V F 033/1 2021 19-7-488 Kumar & Associates LEGEND AND NOTES -Fig. 3 ASPEN BUILDING DEPARTMENT HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 24 HRS 7 HRS 10D - - - 6' IN VMI 414 1 N- 2Q0 .1100 *50#40#30 i 6 /1?E6 (1/4' --- 8'0 90 --__ - -.-__._._ -- -__ —__- --_ r- _ - - _-. _ 1 - 10 .._-.--I _- - -- -- fi -_ _ _ _ _ ____ -__ _ --_ __ rt _ - _ ___.._. _- __ __-- _� 70 _-- - --1- - 30 . -- __ -_ -- --- ___-_- - I ___ - ._ - - _ _. - - - _ 60 - - _ -- _- I i - _ __ - -- - - - - -- 1 40 8 z Fr 1 _ -� _11 50 __ --___- _ - _- __�- I 50 -I -- --- --- - - -L 4O -- -- - 1 - 60 - -. - 1 _ _ - _ 1 - 30 -- - - - - - -- - - I - - - -_ --- _ ---1 - 70 20 I - 80 - _I__ L 1 to 0 T-1- rr1' I i 1-.:I I_11 I I I _ = T. _ _ III I III ' I 1 I I I III r -I -LA 1-ri11- f00 .001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 2.36 4.75 9.5 19 38.1 78.2 127 200 .425 2.0 152 I DIAMETER OF PARTICLES IN MILLIMETERS CLAY TO SILT SAND GRAVEL COBBLES FINE MEDIUM COARSE FINE COARSE GRAVEL 20 % SAND 65 % SILT AND CLAY 15 % LIQUID LIMIT PLASTICITY INDEX SAMPLE OF: Silty Gravelly Sand FROM: Boring 1 ® 3' & 5' (Combined) HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 24 HRS 7 HRS 100 45 MIN 15 MIN 604IN 19MIN 4HJN 1MIN 1200 #100 _050#40#30 #16 #10 418 114 5<8' 3/' 1 2' 3' 5'6' 8'0 --- I 90 _ I- - - _1___ _ -:.- - _ - - - - 10 -_f -- 1_ • 1 1 - so 1 1 •20 I ] - --- - - 1-- 70 - ----- i t 1 1 30 -I I i - I - 1 I u 60 ---- - - - --- - - -- - - - - - - - -- - - ---- - -- -_ - -1 40 ra u 50 --_ --- - - I--- -_- - _ - - -__---__ I 50 -I 1 __ ___ _ - - _- -I- _ W 40 - - _ __ _ - I I_ 1 60 _ I 1 - _ 30 _ - - .-_ - ____ - -_ ----- 70 I 20 --_- __ _ - ___—. ----- - I 1-- - __ - -___ - _ I 80 11:- 1- n _ _ - -- r 1 - - - _..__ 0 -- I. 1 --T Tl 1 - 1 - -I- 1 I I 1111 - 1 -11 1 1.111- - -1 1 1 I I TTTI -(r--T"-I-t TT111 1- 100 .001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 1 2.36 4.75 9.5 19 38.1 76.2 127 200 .425 2.0 152 I DIAMETER OF PARTICLES IN MILLIMETERS I CLAY TO SILT SAND GRAVEL COBBLES FINE MEDIUM COARSE FINE COARSE GRAVEL 38 % SAND 50 % SILT AND CLAY 12 % LIQUID LIMIT PLASTICITY INDEX These test results apply only to the SAMPLE OF: Silty Sand and Gravel FROM: Boring 2 0 10' & 15' (Combined) samples porch were tested. The F m testing report shall not be reproduced, except in full, without the written m approval of Kumar & Associates, Inc. a I, Sieve analysis testing Is perfor/m�ed in o accordance ASTM C136 and/or AS TM TM Q M. 1—STM P ., ' 'I q Rq 19-7-488 Kumar&Associates GRADATION TEST RESULTS 03 F i/J1 /2021 ASPEN BUILDING DEPARTMENT it HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 24 HRS 7 HRS � - TB _ f00 MN — -- 1� IN - '4 0 40 D 1 4 3' 0.0 90 . '.e I _ -- I 10 80 20 70 __--t---. -_ -_ -I---- 30 2 60 - _—_-- - - --- - - _.- - - - - 40 c W 50 I- r a W 40 r' iso i -.— - I —I 0 - - - �_i- -t I 1 1 'I J_J=-LL 1J1__- 1:.- -ii - - l I I_. 1--1 I Li 11.1.1_ - I I_7-1_I_I.I I 100 .001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 12.36 4.75 9.5 19 38.1 76.2 127I 200 DIAMETER OF PARTICLES IN MILLIMETERS tszI CLAY TO SILT SAND GRAVEL COBBLES FINE MEDIUM COARSE FINE COARSE GRAVEL 26 % SAND 62 % SILT AND CLAY 12 % LIQUID LIMIT PLASTICITY INDEX SAMPLE OF: Silty Gravelly Sand FROM: Boring 3 ® 3' & 5' (Combined) HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 24 NRS 7 HRS 100 45 MIN 15 MIN 60 IN 16MIN 4MIN 1MIN 0200 0100 9 0/40 30 /5 III/8 t4 3/3' 3 4" 1 2" 3" 8'8_ 8'0 I I- _ I 90 I. T _ - - -_. - -I 10 80 - �___-_-_ __..-.. I_ , -_�_._ 20 _ _ I - I f - I I — I_ 60 - 1 _ - - - --1._ - _- __ -- - -. I 40 — 1 H - S0 — I = I So I W 40 I I —I 60 E - - I - - _ -- - - - _ - I so - -- I 1 1- 70 -- - - - - - - --I- - 1 - - 20 I -i I- 80 10 -r- -- -- I-- - I — I 90 -- - - — 0 - -I-1 1_L1 I l_ IL1 I II -- -1 - 11T-17.E rt- I i-V1Fi IT" -- I- I ITT rill I 100 .001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 12.36 4.75 9.5 19 38.1 76.2 127 200 .425 2.0 152 I I DIAMETER OF PARTICLES IN MILLIMETERS ND CLAY TO SILT FINE SA MEDIUM (COARSE FINE GRAVEL MEDIUM COBBLES GRAVEL 9 % SAND 79 % SILT AND CLAY 12 % LIQUID LIMIT PLASTICITY INDEX These test results apply only to the SAMPLE OF: Slightly Gravelly Silty Sand FROM: Boring 3 ® 15' & 20' (Combined) samples which were tested. The testing report shall not be reproduced, ,E,o except In full, without the written t approval of Kumar & Associates Inc. Sieve analysis testing fs p rformed I : accordance with ASTM;-D 3 p79 n 1' ASTM C136 and/or ASff,t-1'4�1 ' I• ,t� t �,-�` F. F 19-7-488 Kumar& Associates GRADATION TEST RESULTS I r 0i115/2021 ASPEN BUILDING DEPARTMENT co co \ w « A 7 c d , o e S c > › 2 k › d / / d -4 /2 A A 2 d d / / o. I— Bqz EL in G 2Q5 £ =ku u m I- -J CO co �§ / W § )� 2 LLJ Lu § W § § _ 0 a w CO Li d -J cc§/ - VN N O CLC� re 2 § § / q N N 2 § & CD § / q CD q N 01 0 & c k » ® &k c £ c§ $2 ast \ f ko » § § - R n q q �� G N q 4 \ § 25§ b ©2 $ 2\ / z x i , in / q 0 g E 2 — In - 2 2 ƒ ic : , \ t U U U E -4-41-0- Lu E E VE � z - 0 q m co 03/11/2021 ASPEN BUILDING DEPARTMENT I( A Kumar&Associates,Inc.® Geotechnical and Materials Engineers and Environmental Scientists —�I 1_ TABLE 2 PERCOLATION TEST RESULTS PROJECT NO.19-7-488 HOLE HOLE DEPTH LENGTH OF WATER WATER DROP IN AVERAGE NO. (INCHES) INTERVAL DEPTH AT DEPTH AT WATER PERCOLATION (MIN) START OF END OF LEVEL RATE INTERVAL INTERVAL (INCHES) (MIN.IINCH) (INCHES) (INCHES) B-2 124 4 52 44 8 .5 4 44 37 7 .6 4 37 33 4 1 4 33 29 4 1 4 29 27 2 2 4 27 25 2 2 4 25 23 2 2 4 23 21 2 2 Note: Percolation test was performed in Boring 2 on September 3, 2019. RECEIVED 03/11/2021 ASPEN BUILDING DEPARTMENT