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HomeMy WebLinkAboutFile Documents.210 S West End St.0111.2019 (18).ARBK www.sgm-inc.com GLENWOOD SPRINGS 118 West Sixth St, Suite 200 | Glenwood Springs, CO 81601 | 970.945.1004 Page | 1 August 30, 2022 210 S West End Street Aspen, Colorado 81611 RE: 210 S West End Street, Parcel 2737-182-06-004 As-Built Drainage Memo Dear City of Aspen Engineering: This memo addresses Civil Engineering aspects of the proposed project at 210 S West End Street in the City of Aspen and is intended to be verification for the project with the City of Aspen Engineering Department. The drainage BMPs were reviewed on site on August 25th, 2022. Additional verification was provided by verifying grades on the site as discovered by Peak Surveying, Inc. on August 26th, 2022. Drain inlets, drain outlets, cleanouts, rain gardens, and overflow weirs were observed to be installed per the civil permit plans dated August 4, 2021. The only noticeable difference to the civil permit plans is that the upper rain garden was modified to hold 14 cubic feet of storm water (designed to 20 cubic feet) and the lower rain garden was modified to hold 23 cubic feet of storm water (designed to 17 cubic feet). An overflow weir and weep holes were installed to route water to the lower rain garden. However, the combined volume of storm water storage between the original design and what was installed in the field, remains up to the design and drainage standards at 37 cubic feet of storm water storage. We hope this memo is enough for the as-built drainage approval for the development of this site. Please feel free to contact us if we may provide further information or clarification. Respectfully, Rick L Barth, P.E. Senior Engineer Civil Services Sector SGM CITY OF ASPEN DRAINAGE MAINTENANCE PLAN 210 S WEST END ASPEN, CO 81611 I hereby affirm that this report and the accompanying drawings for the analysis of 210 S West End Drive, Aspen, Colorado was prepared under my direct supervision for the owners thereof in accordance with the provisions of the City of Aspen Urban Runoff Management Plan with proposed 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 designed by others. Permit #: 0011-2021-BCHO August 04, 2021 Rick Barth, P.E. 36749 Prepared by 118 West Sixth Street, Suite 200 Glenwood Springs, CO 81601 970.945.1004 970.945.5948 fax 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design i CITY OF ASPEN DRAINAGE MAINTENANCE PLAN 210 S WEST END ASPEN, CO 81611 REVIEWED BY RICK BARTH SGM Project # 2020-474.001 I:\2020\2020-474-SackResidenceRenovation\001\E-Reports\SGM\Ops & Maintenance\210 S West End Maintenance Plan.docx 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design ii TABLE OF CONTENTS 1.0 Existing Site 3 1.1 Description of Existing Site 3 1.2 Description of Existing Drainage 3 2.0 Proposed Project 3 3.0 Proposed Basins 4 3.1 Basin 1 4 3.2 Basin 2 4 3.3 Basin 3 4 3.4 Basin 4 5 3.5 Basin 5 5 3.6 Basin 6 5 4.0 Peak Flow Methodology 5 5.0 Water Quality Methodology 6 6.0 Maintenance 6 6.1 Pervious Pavers 6 6.2 Rain Garden 6 6.3 Dry well (Flo-Well) 8 7.0 Conclusion 8 LIST OF APPENDICES Appendix A – Proposed Drainage Schematic & Tree Canopy Credits Appendix B – Water Quality Capture Volume Calculations Appendix C – Peak Flow Calculations – Proposed Conditions Appendix D – Soil Study 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design 3 1.0 Existing Site 1.1 Description of Existing Site The physical address of the project is 210 S West End, Aspen, Colorado and it is located on parcel no. 2737-182-06-004. This parcel is approximately 9000 square feet and is owned by West End Home LLC. The existing structure on the parcel is one building that serves as a multi-unit (4-8). The project focuses on landscaping and entrance improvements and changes to the inside and the addition of roof and balcony aspects while preserving access, utilities, and most existing vegetation . The existing residence is 7602 square feet and has three stories with a garage. 1.2 Description of Existing Drainage Existing storm water runs off the existing house either as sheet flow or through gutters and downspouts. Topography of the site suggests that the existing drainage patterns flow from the east side of the property to the west side of the property. Some drainage moves north and south but ultimately flows west once it reaches the gutter and alley. A previously designed flo-well detention system was installed in the fall of 2020 and will be incorporated into the design of the major classification project. There are no apparent erosive or runoff issues (gullies, channels, etc.). A web soil survey was performed and found the soils to be Uracca, moist -Mergel complex, classified as Hydrologic Soil Group B will well-draining soils consisting of very cobbly sandy clay loam to extremely cobbly loamy sand. There is no existing offsite runoff that enters the property as upstream flows appear to be properly directed to the CoA stormwater infrastructure . The property will not require detention beyond the water quality capture volume (WQCV) as it exists within the City of Aspen and can rely on the city’s stormwater infrastructure . 2.0 Proposed Project The primary purpose of this project is to remodel the existing residence. Other improvements include the addition of onsite snowmelt pavement and improving storm water runoff quality. The proposed project is considered a major project as defined by the COA Urban Runoff Management Plan (URMP) because more than 1000 square feet and 25% of the site will be disturbed. The proposed residential remodel will affect the main level, basement, and upper level. Storm water quality improvements consist of 838 square feet of pervious pavers and 55.3 cubic feet of rain gardens. The pervious pavers will be located on the patios and walkways around the property. Rain gardens are located on the west of the residence. 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design 4 3.0 Proposed Basins The proposed site has 6 basins, as shown in Appendix A. Summary of the basins and detailed calculations can be found in Appendix B. Storm water runoff will be routed to designated BMPs for water quality treatment through a combination of grading and gutters with downspouts. All proposed storm water runoff will discharge from the site as sheet flow in a westerly direction to match historical flow patterns. Basins are detailed in the sections that follow, with descriptions on how the required WQCV is treated by BMPs within the basin. WQCV is calculated based on tree canopy credits, proposed rain garden volume, and proposed pervious paver area. 3.1 Basin 1 Basin 1 is located on the northeast corner of the site, along the alley. This basin is 1571 square feet of which 1312 square feet is impervious. A 12.6 cubic foot flo-well detention with 4.7 cubic feet of aggregate volume (gravel) will be used to treat the WQCV for this basin. This flo-well was designed by another engineering firm when the project was currently in a Minor Development category. Grades were adjusted to better fit the overall grading scheme and an overflow pipe was added to the design, directing wate r further downstream to Basin 6. See Appendix A for the proposed location of BMPs in this basin. This area is mostly the north-eastern portion of the building and roof. Storm water will be routed from the roof and driveway to the flo-well via roof drainage, gutter downspouts, and a trench drain in front of the garage. Water infiltrates within the flo-well detention and an overflow pipe is connected to direct excess water to a secondary flo-well in Basin 6. The need for the overflow and second flo-well derives from the garage apron and driveway being in a sump condition. Previous designs for the flo-well had the overflow directing back to the trench drains, creating a circular flow path with no overflow route away from this basin. 3.2 Basin 2 Basin 2 is located on the eastern portion of the site. Storm water runoff will flow from roof areas toward the east property boundary and ultimately west by means of an underdrain. This basin is 1032 square feet of which 828 square feet is impervious. Pervious pavers will be used to treat the WQCV, with remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A for the proposed location of BMPs in this ba sin. After water infiltrates through the pavers and respective substrate, it enters the underdrain and is directed to the rain garden. 3.3 Basin 3 Basin 3 is located on the southeast side of the site and will collect runoff from the southeast portion of the roof. Storm water runoff will flow from roof areas toward the south property boundary and ultimately west by means of an underdrain. This basin is 1688 square feet of which 821 square feet is impervious. Pervious pavers will be used to treat the WQCV, with remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A for the proposed location of BMPs in this basin. After water infiltrates through the paver s and respective substrate, it enters the underdrain and is directed to the rain garden. 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design 5 3.4 Basin 4 Basin 4 is located on the southwest side of the site and will collect runoff from the southwest portion of the roof. Storm water runoff will flow from roof areas toward the south property boundary and ultimately west by means of an underdrain. This basin is 2132 square feet of which 709 square feet is impervious. Pervious pavers will be used to treat the WQCV, with remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A for the proposed location of BMPs in this basin. After water infiltrates through the pavers and respective substrate, it enters the underdrain and is directed to the rain garden. 3.5 Basin 5 Basin 5 is located on the west side of the site and will collect runoff from the west portion of the roof. Storm water runoff will flow from roof areas toward the west property boundary by means of surface flow and an underdrain This basin is 1516 square feet of which 829 square feet is impervious. Pervious pavers will be used to treat the WQCV, with remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A for the proposed location of BMPs in this basin. After water infiltrates through the pa vers and respective substrate, it enters the underdrain and is directed to the rain garden. 3.6 Basin 6 Basin 6 is located on the northwest side of the site and will collect runoff from the northwest portion of the roof. Storm water runoff will flow from roof areas toward the south by means of gutter and surface flow. This basin is 1061 square feet of which 676 square feet is impervious. Pervious pavers will be used to treat the WQCV, with remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A for the proposed location of BMPs in this basin. After water infiltrates through the pavers and respective substrate, it enters the underdrain and is directed to the rain garden. 4.0 Peak Flow Methodology Peak flow methodology was not a determining factor for this site since all stormwater will be treated for water quality and ultimately ending up in the City of Aspen stormwater infrastructure. Pipe sizes were calculated to ensure they are sized appropriately to convey the 100-year storm water. These sizing calculations can be seen below. 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design 6 5.0 Water Quality Methodology The Required WQCV (cf) for each basin on the property was estimated from Figure 8.13 of the URMP based on the basin imperviousness and basin area. Then WQCV credits were estimated based on the proposed areas for pervious pavers and preserved tree canopy (see further discussion of tree canopy credit below). All water quality treatment is based on the instruction of section 8.4.1 in the URMP The Tree Canopy Credit was calculated following the recommendations in section 8.4.1 of the URMP. Detailed calculations for the Tree Canopy Credit can be found in Appendix C. In addition, a map showing the designated trees and their canopy areas is shown in Appendix B. Runoff from all impervious areas will be treated by directing the runoff to pervious pavers and a rain garden. All proposed runoff will leave the property as sheet flow and will flow over grass lawn located in the right of way before entering the curb and gutter system. 6.0 Maintenance 6.1 Pervious Pavers The following maintenance recommendations were found in the Urban Drainage Flood Control District USDCM: Volume 3 Storm water Quality (page 6-15 to 6-17) and will be used as a guide for the maintenance of the proposed pervious pavers. An inspection of the condition and observation of infiltration should be completed annually. The paver s will lose infiltration capabilities over time and it is recommended to use ASTM C1707 Standard Test Method for Infiltration Rate of In Place Pervious Concrete to measure the infiltration rate of the pavers. A regenerative air or vacuumed sweeper should be used twice annually and after any significant site work, like landscaping, is done. However, the timing of vacuum sweeping is variable based on site conditions and biannual vacuuming may be more often than needed. Sand should never be applied to the pave rs for snow removal as this will decrease the permeability of the pavers. The proposed pavers will ha ve snowmelt capabilities, but if snow removal is necessary, mechanical snow removal should be done. If the surface of the paver system ever become s completely clogged, remove and replacement of the first ½ to 1 inch of infill. The use of a push broom is recommended for the replacement of infill. 6.2 Rain Garden Annual inspection of the rain gardens should be taken to ensure that the material is not clogged and inhibiting drainage. Inspection after large storms should also be taken to ensure that the rain garden is draining as it should. Replacement and/or cleaning of the material should be performed when it is observed that the rain garden is performing less tha n optimally in its 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design 7 existing condition. Cleaning of the underdrain should be inspected annually and after large storms that could cause debris to clog the pipes. Cleanouts have been provided to facilitate this maintenance. The following maintenance recommendations were found in the Urban Drain age Flood Control District USDCM: Volume 3 Stormwater Quality (page 6 -5 to 6-7) and will be used as a guide for the maintenance of the proposed facilities. Grass buffers and rain gardens should be inspected at least twice a year for cover and vehicle impacts. Trash and debris should be removed from the buffer at least twice a year. The buffer should be aerated once a year with holes of 2 inches in depth and no more than four inches apart. When aerating the buffer, sprinkler heads and shallow utilities should be marked to ensure they are not damaged. It is recommended to mow only when weeds need to be removed in the first 3 years. After the first 3 years the grass should be maintained at 6 inches or more in height. If grass buffers and rain gardens are no longer holding storm flows or are not draining in 24 hours, immediate maintenance is required. When drainage overflows to areas not intended to detain or convey flows immediate maintenance is required. Additional information on mowing the grass buffer is prov ided in Figure 1. Irrigation is recommended to maintain a healthy vegetation cover. In the early summer and fall, irrigation is typically needed less, but in July and August more irrigation is needed. If native grasses are used, irrigation should not be ne eded after establishment but could be useful during long dry periods. Although irrigation is necessary for the establishment of the grass buffer, overwatering could cause uneven growth which can inhibit the conveyance of runoff and should be avoided. Every year the irrigation system should be drained and blown out before the first winter freeze. The irrigation system should be inspected before reactivation in the spring. Fertilizers and herbicides should be used only on an as -needed basis, and it is recommended to use biodegradable nontoxic fertilizers and herbicides. The following maintenance recommendations were found in the City of Aspen URMP. 210 S West End, Aspen, Colorado August 30, 2022 Drainage Report for Major Design 8 Mowing recommendations for grass buffers or vegetated rain gardens that are included in the Urban Drainage Flood Control District USDCM: Volume 3 Stormwater Quality are provided in the figure below. 6.3 Dry well (Flo-Well) Dry wells must be inspected and maintained yearly to remove sediment and debris that is washed into them. A maintenance plan shall be submitted to the City in the Drainage Report describing the maintenance schedule that will be undertaken by the owners of the new residence or building. Minimum inspection and maintenance requirements include the following: • Inspect dry wells as annually and after every storm exceeding 0.5 inches. • Dispose of sediment, debris/trash, and any other waste material removed from a dry we ll at suitable disposal sites and in compliance with local, state, and federal waste regulations. • Routinely evaluate the drain-down time of the dry well to ensure the maximum time of 24 hours are not being exceeded. If drain -down times are exceeding the maximum, drain the dry well via pumping and clean out the percolation area (the percolation barrel may be jetted to remove sediment accumulated in perforations). Consider drilling additional perforations in the barrel. If slow drainage persists, the system may need to be replaced. 7.0 Conclusion The proposed BMPs (grass buffer, pervious pavers, and rain gardens) are expected to treat 100% of the required WQCV at the 210 S West End project with room to spare. With proper maintenance and installation, these BMPs will meet the criteria outlined in the City of Aspen’s current Urban Runoff Management Plan. E ICV ICV ICV ICV ICV ICV ICV ICV ICV ICV ICV ICV CO CO D D ICV PERVI O U S PAVE R P A T I O 306 SQ . F T . ± COVERED ENTRY 22 . 9 0 ' 11.50' 4.40' 10.30' 17 . 4 0 ' 3.00' 14 . 4 0 ' 3.30' 16 . 1 0 ' 38.70' 16 . 1 0 ' 9.00' 14 . 7 0 ' 9.00' 12 . 1 0 ' 14.70' 32 . 3 0 ' 75.50' CO N C R E T E S I D E W A L K IRRIGATION CONTROL (TYP.) FLOW-WELL RIM= 7931.67' INV IN= 7930.59' SUMP= 7926.66' CONC R E T E P A N CO ICV ICV W G CLEANOUT RIM=7940.37' SWEEP=7939.06' CLEANOUT RIM=7940.38' SWEEP=7938.18' CLEANOUT RIM=7942.00' SWEEP=7938.55' CLEANOUT RIM=7940.45' SWEEP=7938.85' 4" PVC 3 . 0 % FF= 7940.39' FF= 7940.46' RIDGE= 7960.90' FF= 7940.43' 7940 7 9 4 0 79 3 5 7935 79 3 5 CO N C R E T E C U R B A N D G U T T E R FF= 7931.58' FF= 7932.04' FF= 7932.05' 7937.80' 7935.09' TOE WALL 7932.23' TOE WALL 7940.39' 7940.29' IO 6"= 7937.35' 7931.29'7931.23' 7930.46' 7930.46' 7930.49' 7931.38' 7931.33' 7931.41' 7933.42' 7933.16' 7933.33'7932.76' 7932.92' 7931.32' 7931.30' 7931.31'7931.76' 7931.72' 7931.76'7931.96' 7931.89' 7931.96' FLOW-WELL RIM= 7931.90' INV OUT= 7931.23' SUMP= 7926.30' TRENCH DRAIN RIM=7931.53' IO=7930.59' 7932.42' 7932.34' 7932.46' 7932.14' 7932.08' 7932.15' FLOWLINE PAN PERVIOUS PAVER PATIO 177 SQ. FT. ± 7930.90' 7930.99' 7930.55' 7930.40' 7929.71' 7929.19' 7929.30' 7928.88' 7929.08' 7932.71' 7932.55' 7932.02' 7931.93' 7932.40' 7940.42' 7938.13' 7940.39' 7940.45' 7934.71' 7933.16' 7933.57' 7932.75' 7933.21' 7940.48'7940.46' 7940.45' X X METAL PLANTER TIE PLANTER AND FENCE 7940.38' UPPER LEVEL DECK CANTILEVER 7938.04' S 1 4 ° 5 0 ' 4 9 " W 1 0 0 . 0 0 ' N 75° 0 9 ' 1 1 " W 9 0 . 0 0 ' N 1 4 ° 5 0 ' 4 9 " E 1 0 0 . 0 0 ' S 75°0 9 ' 1 1 " E 9 0 . 0 0 ' CONC R E T E STEPS BOULDER WALL(TYP.) PERVIOUS PAVER PATIO 174 SQ. FT.± 4" PV C 0 . 9 0 % FLOW L I N E 1 . 2 % 4" P V C 0 . 8 0 % CON C R E T E SIDE W A L K CONCRETE CURB & GUTTER CONCRETE DRIVE 7940.40' 7940.42' 7940.38' 7940.38' 7940.38' 7940.22' NEW CURB AND GUTTER 7940.32' 7940.30' ICV ADJOINER CONCRETE DRIVE ALLE Y B L O C K 3 2 EAST A S P E N T O W N S I T E 20.90' R . O . W . A S P H A L T WE S T E N D S T R E E T 75 . 0 0 ' R . O . W . A S P H A L T EAST H Y M A N A V E N U E 74.80' R . O . W . A S P H A L T LOT N 7931.98' 7931.98' 7931.54' 7931.78' 210 S. WEST END STREET LOTS K, L, & M MULTILEVEL STONE HOUSE WITH ATTACHED UNITS NO5 REBAR FOUND NO. 5 REBAR & RED PLASTIC CAP FOUND DECIDUOUS TREE 1"X4' (TYP.) PE R V I O U S PA V E R P A T I O 17 4 S Q . F T ± 7931.84' 7931.92' CO UPPE R L E V E L D E C K PERVIOUS PAVER WALK 42 SQ. FT. ± 7959.442 7937.31' 7934.63' 7934.49' 7934.71' 7934.66' TOE WALL 7934.35' TOE WALL 7934.58' 7935.22' TOE WALL 7937.62' TOP WALL 7933.53' TOE WALL 7934.90' TOP WALL 7937.05' TOE WALL 7937.26' TOE WALL RAIN GARDEN 23 C.F.± OVERFLOW WEIR 7934.80' OVERFLOW WEIR 7937.52' RAIN GARDEN 14 C.F.± NOTICE: ACCORDING TO COLORADO LAW, YOU MUST COMMENCE ANY LEGAL ACTION BASED UPON ANY DEFECT IN THIS SURVEY WITHIN THREE YEARS AFTER YOU FIRST DISCOVER SUCH DEFECT. IN NO EVENT MAY ANY ACTION BASED UPON ANY DEFECT IN THIS SURVEY BE COMMENCED MORE THAN TEN YEARS FROM THE DATE OF THE CERTIFICATION SHOWN HEREON. ByNO.Date Project NO.RevisionDrawn By: Checked By: Date: Computer File: P.O. Box 1746 Rifle, CO 81650 Phone (970) 625-1954 Fax (970) 579-7150 www.peaksurveyinginc.com S NW E P e a k S u r v ey i ng, Inc. Es t . 2 0 0 7 22053 1 OF 1 WEST END HOME, LLC ASPEN, COLORAD AS-BUILT SURVEY LOTS K, L, & M, BLOCK 32 210 S. WEST END STREET SF JRN AUGUST 25, 2022 053 DWG AS-BUILT LOTS K, L,&M, BLOCK 32, ACCORDING TO THE IMPROVEMENT SURVEY PLAT PROVIDED PER ASPEN SURVEY ENGINEERS, INC. CITY OF ASPEN, COUNTY OF PITKIN, STATE OF COLORADO AS-BUILT SURVEY CERTIFICATION STATEMENT: I, THE UNDERSIGNED REGISTERED LAND SURVEYOR, HEREBY CERTIFY THAT THE ELEVATIONS, GRADING AND DRAINAGE FEATURES SHOWN ON THE PROPERTY DESCRIBED AS:LOTS K, L, & M, BLOCK 32 WERE DEVELOPED FROM SURVEYING THE PROPERTY ON THE DATE OF JULY 13, 2022 AND ACCURATELY DEPICT THE ELEVATIONS EXISTING DURING THE SURVEY. THE ELEVATIONS MAY CHANGE SUBSEQUENT TO THE SURVEY DUE TO SUBSIDENCE, UPHEAVAL, EROSION, ACTS OF MAN OR OTHER FACTORS. THEREFORE, THIS CERTIFICATE MAY NOT ACCURATELY DEPICT ELEVATIONS, GRADING AND DRAINAGE PATTERN AFTER THE DATE OF THE SURVEY. EASEMENTS ARE SHOWN PER THE PLAT UNLESS NOTED OTHERWISE. NO PART OF THIS LOT LIES WITHIN THE 100 YEAR FLOODPLAIN AS DEFINED BY FEMA, EXCEPT AS NOTED. ERROR OF CLOSURE FOR THIS IMPROVEMENT SURVEY PLAT IS LESS THAN 1:15,000. BY:______________________________________ DATE:_______________________ JASON R. NEIL, P.L.S. NO. 37935 FOR AND BEHALF OF PEAK SURVEYING, INC. AS-BUILT ENGINEERING CERTIFICATION STATEMENT: I, THE UNDERSIGNED REGISTERED PROFESSIONAL ENGINEER, CERTIFY THAT I HAVE INSPECTED THE AS-BUILT SURVEY DATA FOR PROJECT SITE: LOTS K, L, & M, BLOCK 36, AND HAVE CONCLUDED THAT THE PROPERTY WILL DRAIN ADEQUATELY IN CONFORMANCE WITH THE DRAINAGE PLAN SUBMITTED AND APPROVED BY THE CITY ON DATE: ____________________. BY: _______________________________________ DATE: _________________ PE LICENSE NO. _______________________ NOTES: 1) THIS PROPERTY IS SUBJECT TO RESERVATIONS, RESTRICTIONS, COVENANTS, BUILDING SETBACKS AND EASEMENTS OF RECORD, OR IN PLACE. THIS SURVEY WAS PREPARED WITHOUT THE BENEFIT OF A TITLE COMMITMENT THEREFORE, EXCEPTIONS TO TITLE THAT MAY AFFECT THE SUBJECT PROPERTY HAVE NOT BEEN RESEARCHED BY PEAK SURVEYING, INC. 2) THE DATE OF THIS SURVEY WAS JULY 13, & 29, 2022. 3) BASIS OF BEARINGS FOR THIS SURVEY IS A BEARING OF N75°09'11""W BETWEEN THE SOUTHWEST CORNER OF LOT K, A #5 REBAR FOUND IN PLACE AND THE SOUTHEAST CORNER OF LOT M, A #5 REBAR AND RED PLASTIC CAP P.L.S.# ILLEGIBLE FOUND IN PLACE. 4) UNITS OF MEASURE FOR ALL DIMENSIONS SHOWN HEREON IS U.S. SURVEY FEET. 5) THIS SURVEY IS BASED ON THE DESIGN SURVEY PROVIDED BY ASPEN SURVEY ENGINEEERS INC, DATE AUGUST. 2018 AND CORNERS FOUND IN PLACE. 6) ELEVATIONS ARE BASED ON A ON-SITE ELEVATION ON A SURVEY PREPARED BY ASPEN SURVEY ENGINEERS INC, DATED AUGUST, 2018 (1988 DATUM) YIELDING AN ON-SITE ELEVATION OF 7925.42' ON THE COA MONUMENT #4, A TBM AS SHOWN. CONTOUR INTERVAL EQUALS 1 FOOT. 7) THE SUBJECT PROPERTY WAS UNDER CONSTRUCTION AT THE TIME OF SURVEY. N E S W 0 30 60 90 120 150 180 210 240 270 300 330 P e a k S u r v e y i n g , I n c . 010 10 20 405 BOUNDARY LINE TYPE LEGEND STORM SEWER ELECTRIC EASEMENT EX-ST EX-UE ASPHALT CONCRETE SYMBOL LEGEND WATER SHUT OFF GAS METER G SET MONUMENT ELEC. TRANS. EDGE OF ROAD IRRIGATION VALVE FOUND MONUMENT SEWER MANHOLE ELEC. METER S SPOT ELEVATIONS AIR COND. UNIT OSW SETBACK PVC DRAIN LINE TELEPHONE T CABLE TV CTV GASLINE G FIBER OPTIC FO TELEPHONE T STORM DRAIN D ELEC. OUTLET ADJ. BOUNDARY CABLE TV PED. STREET LIGHT SEWER LINE WATER LINE W 0000.00' E E A.C. ICV 08/25/22 08/25/22 COL O R A D O L I CE N S E D P R O F E SSIONAL L A N D S U RVEYO R JAS O N R . N E I L 37935 08.30.2022 Graphic Scale In Feet: 1" = 5' 0 2 5 10 Title: Drainage Plan Re v i s i o n # Dwg No. 21 0 S W e s t E n d S t r e e t As p e n , C o l o r a d o 8 1 6 1 1 Job No. Drawn by: Date: File: PE:QC: 2020-474 JAK 08.04.2021 RLB Sack-GradingPlan DJC 11 8 W e s t S i x t h S t r e e t , S u i t e 2 0 0 Gl e n w o o d S p r i n g s , C O 8 1 6 0 1 97 0 . 9 4 5 . 1 0 0 4 w w w . s g m - i n c . c o m Da t e By : C4 10Of : Pe r m i t S e t Pr o j e c t M i l e s t o n e :