Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
Drainage Reports - 09/30/2025
302 CONIFER APARTMENTS 302 Conifer Street Fort Collins, Colorado FINALS DRAINAGE REPORT (Phase III Drainage Report) Strategic Land Solutions, Inc. JN: 24-002-46 Report Date/History: November 15, 2024 Revised: February 12, 2025 Revised: March 21, 2025 Prepared for: ATTN: Mr. Harsh Parikh - Principal Email: harsh@santulanarch.com Prepared by: Robert J. Palmer, P.E., as President Strategic Land Solutions, Inc. 2595 Ponderosa Road Franktown, CO 80116 Phone (720) 384-7661 Email rpalmer@strategicls.net City of Fort Collins Approved Plans Approved by: Date: Wes Lamarque 9/30/2025 2025 Copyright © by Strategic Land Solutions, Inc. All rights reserved. This report or parts thereof may not be reproduced in any form, stored in a retrieval system, or transmitted in any form by any means – electronic, mechanical, photocopy, recording, or otherwise – without prior written permission of Strategic Land Solutions, Inc., except as provided by United States of America copyright law. Published by Strategic Land Solutions, Inc. (2595 Ponderosa Road, Franktown, CO 80116, www.strategicls.net, 720-384-7661 phone) 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page i TABLE OF CONTENTS TABLE OF CONTENTS .................................................................................................................................................. i ENGINEER’S AND DEVELOPER’S CERTIFICATIONS .................................................................................................. ii 1. GENERAL LOCATION AND DESCRIPTION ......................................................................................................... 1 1.1. LOCATION ................................................................................................................................................ 1 1.2. DESCRIPTION OF PROPERTY .................................................................................................................... 1 2. DRAINAGE BASINS AND SUB-BASINS ............................................................................................................... 1 2.1. MAJOR BASIN DESCRIPTION .................................................................................................................. 1 2.2. SUB-BASIN DESCRIPTION ........................................................................................................................ 1 3. DRAINAGE DESIGN CRITERIA ............................................................................................................................ 2 3.1. REGULATIONS .......................................................................................................................................... 2 3.2. DEVELOPMENT RESTRAINTS ..................................................................................................................... 2 3.3. HYDROLOGICAL CRITERIA ...................................................................................................................... 2 3.4. HYDRAULIC CRITERIA .............................................................................................................................. 2 3.5. WATER QUALITY REQUIREMENTS ............................................................................................................. 3 3.6. WAIVERS FROM CRITERIA ....................................................................................................................... 3 4. DRAINAGE FACILITY DESIGN ............................................................................................................................. 3 4.1. GENERAL CONCEPT ................................................................................................................................ 3 4.2. SPECIFIC DETAILS ..................................................................................................................................... 3 5. CONCLUSIONS ................................................................................................................................................... 4 5.1. COMPLIANCE WITH STANDARDS ........................................................................................................... 4 5.2. DESIGN ..................................................................................................................................................... 4 6. REFERENCES ........................................................................................................................................................ 5 LIST OF FIGURES Figure 1 - SITE LOCATION MAP ............................................................................................................................... 1 Figure 2 - SITE LOCATION ENLARGEMENT .............................................................................................................. 1 APPENDICES APPENDIX A: HYDROLOGIC COMPUTATIONS APPENDIX B: HYDRAULIC COMPUTATIONS APPENDIX C: MAP POCKET 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page ii ENGINEER’S CERTIFICATION This STORMWATER MANAGEMENT REPORT was prepared by me or under my direct supervision in accordance with the provisions of the City of Fort Collins, Storm Drainage Design and Technical Manual for the owners thereof. It is understood that the City of Fort Collins does not and will not assume liability for the drainage facilities designed by others. SIGNATURE: Robert J. Palmer, PE CO PE #36320 DEVELOPER’S CERTIFICATION THE SZANTON COMPANY (hereinafter DEVELOPER) hereby certifies that the drainage facilities for the project detailed within this Report will be constructed according to the design presented. It is understood that the City of Fort Collins does not and will not assume liability for the drainage facilities designed and/or certified by my engineer and that the City of Fort Collins reviews drainage plans pursuant to Colorado Revised Statutes, Title 24, Article 28; but cannot, on behalf of DEVELOPER, guarantee that final drainage design review will absolve DEVELOPER and/or their successor and/or assigns of future liability for improper design. SIGNATURE: Printed Name – Title – Carl Szanton Partner 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page 1 1. GENERAL LOCATION AND DESCRIPTION 1.1. LOCATION The planned Apartments and Retail will consist of 50 new apartment units in a single building, located at 302 Conifer, within the southwest ¼ of Section 01, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. The site is bounded on the north by existing commercial, on the west by Blue Spruce Drive, on the east by a drainage ditch and vacant land, and on south by the Conifer Street. Figure 1 - SITE LOCATION MAP Figure 2 - SITE LOCATION ENLARGEMENT 1.2. DESCRIPTION OF PROPERTY The site currently encompasses approximately 1.19-acres of vacant land covered by non-native vegetation. The proposed redevelopment of this property includes the construction of a 50-unit affordable apartment building with surface parking, landscaping, and drainage facilities. 2. DRAINAGE BASINS AND SUB-BASINS 2.1. MAJOR BASIN DESCRIPTION The site lies within the Cache La Poudre River Drainage Basin. Runoff from the site drains to adjacent streets, where it is captured in the gutter and conveyed east to the storm drain system located Conifer Street, and ultimately to the South Platte River. There are no adjacent irrigation facilities tributary to this site. There is a drainageway running along the east side of the site. The project is located within Flood Zone X, as shown on the National Flood Insurance Program’s Flood Insurance map community panel 08069C0977G with an effective date of June 17, 2008, City of Fort Collins. According to the Natural Resources Conservation Service (NRCS) web site contains Caruso Caly Loam, 0% to 1%, (98.9%), which has a hydraulic rating D, and Nunn Clay Loam, 0% to 1% slope (1.1%), which has a hydraulic rating of C. As shown in the geotechnical report, ground water was encountered at approximately 9-feet. The invert of the detention is located 2-feet below the existing grade. Therefore, groundwater should not impact this development. Any groundwater or de-watering discharge (temporary or permanent) will require CCD Wastewater review and possibly a state discharge permit. Contact Jeff Williams at 303-446-3588 for additional details. 2.2. SUB-BASIN DESCRIPTION Under proposed conditions, the site is roughly divided into 7 drainage sub-basins. The following is a description of the three proposed sub-basins A, B, and C. 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page 2 Basin A contains approximately 0.972 acres, and it is comprised of the building rooftop, the parking area, sidewalks, and landscaping along the north side of the site, and the most of parking lot, sidewalks and landscaping along the east side of the site. Runoff from this basin is captured by roof drains and conveyed to the porous pavers making up most of the parking areas north and east of the building. The runoff is treated for water quality, and detained for storm water attenuation, before being released at allowable rates into the drainage swale east of the site. Basin A incorporates 82% of the proposed site. Basin B contains approximately 0.195 acre, and it is comprised of landscaped areas, patios, and sidewalks along Conifer Street. Runoff from this area bypasses the porous pavement detention, and sheet flows to the gutter in Conifer Street. The runoff is then conveyed west in the Conifer gutter to an existing storm inlet. Basin C contains approximately 0.019 acre, and it is comprised of landscaped along Blue Spruce Street. Runoff from this area bypasses the porous pavement detention, and sheet flows to the gutter in Blue Spruce. The runoff is then conveyed south in the Blue Spruce gutter to an existing storm inlet just north of Conifer Street. 3. DRAINAGE DESIGN CRITERIA 3.1. REGULATIONS This drainage report was prepared in compliance with the following criteria: City of Fort Collins, Stormwater Criteria Manual Mile High Flood Control District (MHFD) Mile High Flood District Criteria Manual During construction, disturbed areas will be stabilized for erosion and sediment control in accordance with City of Fort Collins and MHFD Criteria. The methods used to control erosion and sediment during construction of this project will comply with the non-structural and structural Best Management Practices (BMPs) described within the City of Fort Collins and MHFD manuals. A separate Erosion Control Report will be submitted to Fort Collins Public Works for approval. No deviation from the City of Fort Collins Criteria is being requested except for the use of an underground detention vault. 3.2. DEVELOPMENT RESTRAINTS The site is confined by existing improvements on all sides, and there is no existing underground storm drain available to outfall the detention. Therefore, porous pavement is being utilized for detention and water quality, with an outfall to the shallow drainage swale east of the site. 3.3. HYDROLOGIC CRITERIA Runoff was calculated per the City of Fort Collins Criteria and MHFD. Rainfall intensity was taken from IDF Table 3.4-1 of the City of Fort Collins Stormwater Criteria, and runoff coefficients were taken from Table 3.2-2 of the City of Fort Collins Stormwater Criteria. The rational method was used to calculate runoff from the proposed development. The following formula was used to determine the runoff values: Q=CIA Where Q = Storm runoff, cubic feet per second (CFS) C = Runoff coefficient I = Storm intensity, inches per hour A = Drainage area, acres 3.4. HYDRAULIC CRITERIA The pipe hydraulics for the detention vault outfall pipe are modeled using LDD Pipe using a friction coefficient of 0.013 for concrete and 0.011 for PVC. The hydraulic grade lines are shown on the pipe profiles located in the appendix of this report. Inlet and exit losses are calculated as part of the pipe program. A printout of the program output is located in the appendix of this report. 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page 3 The hydraulic design has been done in accordance with the City of Fort Collins Stormwater Criteria. 3.5. WATER QUALITY REQUIREMENTS Stormwater quality for the project will be provided by porous pavement with a stormwater detention reservoir. 3.6. WAIVERS FROM CRITERIA No deviation from the City of Fort Collins Criteria is being requested except for the use of porous pavement for stormwater detention and water quality treatment. 4. DRAINAGE FACILITY DESIGN 4.1. GENERAL CONCEPT Runoff from the building will be captured by roof drains, where it will flow to the porous pavement for treatment. Runoff from the north and east areas of the site sheet flow to porous pavement areas, where it is treated for water quality. A drain course under the pavers will be utilized for stormwater detention. 4.2. SPECIFIC DETAILS As described above, water quality will be provided by a porous paver system. The runoff will be detained for the 100-year runoff volume. The runoff release rate from the underground detention will be controlled by an orifice plate inside of the outlet control structure (OCS). There is no public storm drain facilities immediately adjacent to the site, so the runoff from the underground detention pond will be released directly to the drainage swale east of the site. The primary overflow for the underground detention is through the OCS overflow weir. The OCS overflow will spill into the outfall pipe, which is designed to convey 120% of the 100-year basin runoff. A 10-foot Type R inlet is included to capture runoff form the porous paver area in excess of the water quality event. The building finish floor elevation is set a minimum of 2-feet above the pond overflow WSEL. The detention is designed per Section 2.3 of the Fort Collins Stormwater Criteria Manual. The water quality is designed per the City of Fort Collins Stormwater Criteria Chapter 7. This site meets the four-step process as follows. 1. The site is designed to minimize impervious areas. The site contains the minimum parking, the minimum width drive aisles, and utilizes the minimum amount of paved pedestrian access needed to serve the site. Furthermore, porous pavers are being utilized to further reduce the site imperviousness. Runoff from pervious areas is detached from the drainage system, passed over landscaped buffers, before being conveyed to the porous pavers. Furthermore, the storm inlet contains a 6” sump at the bottom to allow heavy sediment to drop out of the system prior to reaching the channel outfall. 2. The porous pavers are designed to capture runoff form the site, detain the runoff for water quality, releasing the runoff through the orifice plat to mimic natural site runoff. The release design was created to allow developed site releases to more closely mimic natural channel flow. 3. As discussed above, the 100-year release method is being utilized to mimic normal stream runoff conditions. This style of release helps stabilize channel erosion, road embankment erosion, and reduces the need for mechanical embankment stabilization. 4. The site is designed with several source controls to aid in water quality. As described above, the storm inlet IS sumped to allow heavy sediment removal prior to reaching the outfall and detention course. The trash enclosure is located away from the storm inlets, in a manner that allows easy trash truck access. The trash enclosure is also designed with pedestrian access from the rear, so the trash gates can remain closed protecting the dumpsters from wind. The site is also designed to detach runoff from A piped system for POROUS PAVER pre-treatment where feasible. Furthermore, the site will utilize several trash receptacles to 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page 4 aid in trash control, and all areas of the site will be covered by landscaping, building, or pavement. No bare land will remain upon final construction. DETENTION POND A DESCRIPTION REQUIRED PROVIDED Water Quality Volume 726 Cubic Feet 726 Cubic Feet Water Quality WSEL 4965.95 4965.95 Water Quality Release Rate 0.0168 CFS 0.0168 CFS 100yr Detention Volume (Total Storage) 8,390 Cubic Feet 8,390 Cubic Feet 100yr Detention WSEL 4967.75 4967.75 100yr Detention Release Rate 0.194 CFS 0.194 CFS 4.3. OPERATION AND MAINTENANCE PLAN The porous pavers will be inspected for trash removal weekly. The porous pavers will be inspected for sedimentation bi-annually, with annual cleaning and sedimental removal expected. The underground detention course inspection PORTS shall be open monthly, and any trash shall be removed as needed. It is expected that with proper maintenance of the porous pavers will require pressure washing and the OCS will require vacuuming at approximately 2-year intervals. All maintenance is the responsibility of the property owner. The City of Fort Collins is not responsible for maintenance of private onsite facilities. 5. CONCLUSIONS 5.1. COMPLIANCE WITH STANDARDS This stormwater Management Report was prepared in compliance with the City of Fort Collins Stormwater Criteria and the MHFD Urban Storm Drainage Criteria Manual. No variances will be requested except for the use of an underground detention vault system. 5.2. MAINTENANCE All proposed drainage facilities proposed with this project are private and will be maintained by the property owner per section 4.3 of this report. 5.3. DESIGN This project meets the requirements shown in the City of Fort Collins Stormwater Criteria and the MHFD Urban Storm Drainage Criteria Manual. Furthermore, as discussed in section 2.1 of this report, groundwater is not expected to affect this project. As such, this project should not have a negative impact on the surrounding developments and existing drainage facilities. 302 Conifer Apartments (302 Conifer St. Fort Collins, CO) FINAL DRAINAGE REPORT March 21, 2025 Page 5 6. REFERENCES 1. City of Fort Collins, Stormwater Criteria, December 2018. 2. Flood Insurance Rate Map – City of Fort Collins, Colorado, Community Panel Number 08069C0977G, Effective date of June 17, 2008. 3. Geotechnical Engineering Study 302 Conifer Street. – Fort Collins, Colorado, Kumar and Associates, November 07, 2024 4. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3); Mile High Flood District, 2021 (latest revision). APPENDIX A HYDROLOGIC COMPUTATIONS AAppppeennddiixx AA –– HH DDRROOLLOOGGIICC CCOOMMPPUU AA IIOONNSS 302 CONIFER APARTMENTS-FORT COLLINS, CO - Drainage Calculations LAND USAGE FOR EACH SUB-BASIN LAND USAGE PERCENT 2-YR 5-YR 100-YR SUM IMPERVIOUS RUNOFF RUNOFF RUNOFF OF COEFF. COEFF. COEFF.AREA (%)C2 C5 C100 A B C E1 E2 (ACRE) LANDSCAPE 20 0.20 0.20 0.25 0.186 0.135 0.019 0.133 0.991 0.340 ROOF 95 0.95 0.95 1.00 0.327 0.327 POROUS PAVERS 40 0.50 0.50 0.63 0.262 DRIVES AND WALKS (IMPERVIOUS) 95 0.95 0.95 1.00 0.197 0.060 0.013 0.049 0.257 Total 0.972 0.195 0.019 0.146 1.040 0.000 1.186 COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENTS SUB-BASIN EFFECTIVE COMPOSITE COMPOSITE COMPOSITE AREA % IMPERVIOUS C2 C5 C100 acres A 65.82 0.69 0.69 0.76 0.972 B 43.08 0.43 0.41 0.48 0.195 C 20.00 0.20 0.20 0.25 0.019 Total Site 61.35 0.64 0.64 0.70 1.186 E1 (EXISTING BASIN) 26.68 0.27 0.27 0.32 0.146 E2 (EXISTING BASIN) 23.53 0.24 0.24 0.29 1.040 TOTAL EXISTING 23.92 0.24 0.24 0.29 1.186 AREA SUBDIVISION: CALCULATED BY: DATE:t c = t i + t t FINAL REMARKS t c DESIGN AREA C5 LENGTH SLOPE t i LENGTH SLOPE VEL t t COMP TOTAL t c =(L/180)+10 Ac Ft % Min Ft % FPS Min t c LENGTH Min Min (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) MAIN DETENTION POND 1 0.972 0.69 83 2 5.3 331 0.50 1.50 3.7 9.0 414 12.3 9.0 2 0.195 0.41 25 2 4.9 403 0.43 1.40 4.8 9.7 428 12.4 9.7 3 0.019 0.20 21 2 5.9 51 0.76 1.80 0.5 6.4 72 10.4 6.4 4 1.186 0.64 83 2 6.0 331 0.50 1.50 3.7 9.7 414 12.3 9.7 E1 0.146 0.27 95 0.7 16.4 111 0.60 1.40 1.3 17.7 206 11.1 11.1 USE 10 MIN. MAX E2 1.040 0.24 145 2.3 14.1 256 0.40 1.40 3.0 17.2 401 12.2 12.2 USE 10 MIN. MAX ETOTAL 1.186 0.24 145 2.3 14.1 256 0.40 1.00 4.3 18.4 401 12.2 12.2 USE 10 MIN. MAX STORM DRAINGE DESIGN AND TECHNICAL CRITERIA DATA TIME (t i ) (t i )(URBANIZED BASINS) SUB-BASIN INITIAL / OVERLAND TRAVEL TIME t c CHECK STANDARD FORM SF-2 TIME OF CONCENTRATION YEAR 302 Conifer Fort Collins, CO Robert Palmer 02/13/25 SUBDIVISION: CALCULATED BY: DATE: DESIGN STORM: AR E A DE S I G N AR E A (A C ) RU N O F F CO E F F tc (M I N ) C* A (A C ) i (I N / H R ) Q (C F S ) tc (M I N ) ( C * A ) (A C ) i (I N / H R ) Q (C F S ) SL O P E (% ) ST R E E T FL O W ( C F S ) DE S I G N FL O W ( C F S ) SL O P E (% ) PI P E SI Z E LE N G T H (F T ) VE L O C I T Y (F P S ) tt (M I N ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) 14 13 12 11 10 2.21 9 0.09 0.63 0.63 0.54 0.54 8 ETOTAL E3 E1-E2 1.19 0.24 0.24 10.0 10.0 10.0 2.21 0.09 0.24 2.21 0.28 0.04 7 E2 E2 E2 1.04 6 E1 E1 E1 0.15 0.27 5 4 A-C 1.19 0.64 9.7 2.69 1.69 3 Basin C 3 C 0.754Total Site 0.02 0.20 6.4 2.24 1.69 0.01 0.19 0.00 0.01 0.192Basin B 2 B 0.20 0.43 9.7 0.08 2.24 1.539.0 STREET PIPE TRAVEL TIME 0.67 2.30 1.531Basin A 1 A 0.97 0.69 2-Yr STREET DE S I G N P O I N T DIRECT RUNOFF TOTAL RUNOFF REMARKS Robert Palmer 02/13/25 STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (Rational Method Procedure) 302 Conifer Fort Collins, CO SUBDIVISION: CALCULATED BY: DATE: DESIGN STORM: AR E A DE S I G N AR E A (A C ) RU N O F F CO E F F tc (M I N ) C* A (A C ) i (I N / H R ) Q (C F S ) tc (M I N ) ( C * A ) (A C ) i (I N / H R ) Q (C F S ) SL O P E (% ) ST R E E T FL O W ( C F S ) DE S I G N FL O W ( C F S ) SL O P E (% ) PI P E SI Z E LE N G T H (F T ) VE L O C I T Y (F P S ) tt (M I N ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (Rational Method Procedure) 302 Conifer Fort Collins, CO Robert Palmer 02/13/25 100-Yr STREET DE S I G N P O I N T DIRECT RUNOFF TOTAL RUNOFF STREET PIPE TRAVEL TIME REMARKS 1 Basin A 1 A 0.97 0.76 9.0 0.73 8.03 5.90 5.90 2 Basin B 2 B 0.20 0.48 9.7 0.09 7.81 0.73 0.73 3 Basin C 3 C 0.02 0.25 6.4 0.00 9.11 0.04 0.04 4 Total Site 4 A-C 1.19 0.70 9.7 0.83 7.81 6.50 6.50 5 6 E1 E1 E1 0.15 0.32 10.0 0.05 7.72 0.36 0.36 2.297E2 E2 E2 1.04 0.29 10.0 0.30 7.72 2.29 8 ETOTAL E3 E1-E2 1.19 0.29 10.0 0.34 7.72 2.65 2.65 9 10 11 12 13 14 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.2 Runoff Coefficients Page 5 Table 3.2-2. Surface Type - Runoff Coefficients Asphalt, Concrete 0.95 Rooftop 0.95 Recycled Asphalt 0.80 Gravel 0.50 Pavers 0.50 Lawns, Sandy Soil, Flat Slope < 2% 0.10 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.20 Lawns, Clayey Soil, Flat Slope < 2% 0.20 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 0.35 3.2.1 Composite Runoff Coefficients Drainage sub-basins are frequently composed of land that has multiple surface types or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: ( ) t n i ii A xAC C ∑ ==1 Equation 5-2 Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (Ai), dimensionless Ai = Area of Surface with Runoff Coefficient of Ci, acres or square feet n = Number of different surfaces to be considered At = Total Area over which C is applicable, acres or square feet 3.2.2 Runoff Coefficient Frequency Adjustment Factor The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapotranspiration and other losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 8 Table 3.4-1. IDF Table for Rational Method Duration (min) 2-year 10-year 100-year Duration (min) 2-year 10-year 100-year 5 2.85 4.87 9.95 39 1.09 1.86 3.8 6 2.67 4.56 9.31 40 1.07 1.83 3.74 7 2.52 4.31 8.80 41 1.05 1.80 3.68 8 2.40 4.10 8.38 42 1.04 1.77 3.62 9 2.30 3.93 8.03 43 1.02 1.74 3.56 10 2.21 3.78 7.72 44 1.01 1.72 3.51 11 2.13 3.63 7.42 45 0.99 1.69 3.46 12 2.05 3.50 7.16 46 0.98 1.67 3.41 13 1.98 3.39 6.92 47 0.96 1.64 3.36 14 1.92 3.29 6.71 48 0.95 1.62 3.31 15 1.87 3.19 6.52 49 0.94 1.6 3.27 16 1.81 3.08 6.30 50 0.92 1.58 3.23 17 1.75 2.99 6.10 51 0.91 1.56 3.18 18 1.70 2.90 5.92 52 0.9 1.54 3.14 19 1.65 2.82 5.75 53 0.89 1.52 3.10 20 1.61 2.74 5.60 54 0.88 1.50 3.07 21 1.56 2.67 5.46 55 0.87 1.48 3.03 22 1.53 2.61 5.32 56 0.86 1.47 2.99 23 1.49 2.55 5.20 57 0.85 1.45 2.96 24 1.46 2.49 5.09 58 0.84 1.43 2.92 25 1.43 2.44 4.98 59 0.83 1.42 2.89 26 1.4 2.39 4.87 60 0.82 1.4 2.86 27 1.37 2.34 4.78 65 0.78 1.32 2.71 28 1.34 2.29 4.69 70 0.73 1.25 2.59 29 1.32 2.25 4.60 75 0.70 1.19 2.48 30 1.30 2.21 4.52 80 0.66 1.14 2.38 31 1.27 2.16 4.42 85 0.64 1.09 2.29 32 1.24 2.12 4.33 90 0.61 1.05 2.21 33 1.22 2.08 4.24 95 0.58 1.01 2.13 34 1.19 2.04 4.16 100 0.56 0.97 2.06 35 1.17 2.00 4.08 105 0.54 0.94 2.00 36 1.15 1.96 4.01 110 0.52 0.91 1.94 37 1.16 1.93 3.93 115 0.51 0.88 1.88 38 1.11 1.89 3.87 120 0.49 0.86 1.84 B. HYDRAULIC COMPUTATIONS AAppppeennddiixx BB –– HH DDRRAAUULLIICC CCOOMMPPUU AA IIOONNSS Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Type of Permeable Pavement Section A) What type of section of permeable pavement is used? (Based on the land use and activities, proximity to adjacent structures and soil characteristics.) B) What type of wearing course? 2. Required Storage Volume A) Effective Imperviousness of Area Tributary to Permeable Pavement, Ia Ia =65.8 % B) Tributary Area's Imperviousness Ratio (I = Ia / 100)i =0.658 C) Tributary Watershed Area ATotal = 42,340 sq ft (including area of permeable pavement system) D) Area of Permeable Pavement System APPS =11,231 sq ft (Minimum recommended permeable pavement area = 10481 sq ft) E) Impervious Tributary Ratio RT =1.8 (Contributing Imperviuos Area / Permeable Pavement Ratio) F) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 726 cu ft (WQCV = (0.8 * (0.91 * i3 - 1.19 * i2 + 0.78 * i) / 12) * Area) G) Is flood control volume being added? Provide overflow to carry runoff directly into the reservoir layer to ensure use of flood control volume H) Total Volume Needed VTotal =8,390 cu ft regardless of infiltration rates. 3. Depth of Reservoir A) Minimum Depth of Reservoir Dmin =23.5 inches (Minimum recommended depth is 6 inches) B) Is the slope of the reservoir/subgrade interface equal to 0%? C) Porosity (Porous Gravel Pavement < 0.3, Others < 0.40)P =0.40 D) Slope of the Base Course/Subgrade Interface S = ft / ft E) Length Between Lateral Flow Barriers L = ft F) Volume Provided Based on Depth of Base Course V = 8,423 cu ft Flat or Stepped: V = P * ((Dmin-1)/12) * Area Sloped: V = P * [(Dmin - (Dmin - 6*SL-1)) / 12] * Area 4. Lateral Flow Barriers A) Type of Lateral Flow Barriers B) Number of Permeable Pavement Cells Cells = 5. Perimeter Barrier A) Is a perimeter barrier provided on all sides of the pavement system? (Recommeded for PICP, concrete grid pavement, or for any no-infiltration section.) 302 Conifer 302 Conifer - Fort Collins, CO Design Procedure Form: Permeable Pavement Systems (PPS) Robert Palmer Strategic Land Solutions March 24, 2025 UD-BMP (Version 3.06, November 2016) Choose One No Infiltration Partial Infiltration Section Full Infiltration Section Choose One YES NO Choose One YES- Flat or Stepped Installation NO- Sloped Installation Choose One Concrete Walls PVC geomembrane installed normal to flow N/A- Flat installation Other (Describe): Choose One YES NO Choose One PICP Concrete Grid Pavement Pervious Concrete Porous Gravel SAND FILTER_v3.06-1.xlsm, PPS 3/24/2025, 8:34 AM Sheet 2 of 2 Designer: Company: Date: Project: Location: 6. Filter Material and Underdrain System A) Is the underdrain placed below a 6-inch thick layer of CDOT Class C filter material? B) Diameter of Slotted Pipe (slot dimensions per Table PPs-2) C) Distance from the Lowest Elevation of the Storage Volume y = 2.0 ft (i.e. the bottom of the base course to the center of the orifice) 7. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is there a minimum 30 mil thick impermeable PVC geomembrane liner on the bottom and sides of the basin, extending up to the top of the base course? B) CDOT Class B Separator Fabric 8. Outlet (Assumes each cell has similar area, subgrade slope, and length between lateral barriers (unless subgrade is flat). Calculate cells individually where this varies.) A) Depth of WQCV in the Reservoir DWQCV =1.94 inches (Elevation of the Flood Control Outlet) B) Diameter of Orifice for 12-hour Drain Time DOrifice =inches (Use a minimum orifice diameter of 3/8-inches) Notes: 302 Conifer Design Procedure Form: Permeable Pavement Systems (PPS) Robert Palmer Strategic Land Solutions March 24, 2025 302 Conifer - Fort Collins, CO Choose One YES NO Choose One 4-inch 6-inch Choose One Choose One YES NO Placed above the liner Placed above and below the liner N/A SAND FILTER_v3.06-1.xlsm, PPS 3/24/2025, 8:34 AM REQUIRED 100-YEAR DETENTION MINUTES RUNOFF COEFFICIENT C RAINFALL INTENSITY (I) Area (A) (60T) Vi Qout Vo Vs 0 0.76 0.00 0.972 0 0 0.194 0 0 Cubic Feet 5 0.76 9.95 0.972 300 2205.0792 0.194 58.2 2146.8792 Cubic Feet 10 0.76 7.72 0.972 600 3421.75104 0.194 116.4 3305.35104 Cubic Feet 15 0.76 6.52 0.972 900 4334.80896 0.194 174.6 4160.20896 Cubic Feet 20 0.76 5.60 0.972 1200 4964.1984 0.194 232.8 4731.3984 Cubic Feet 25 0.76 4.98 0.972 1500 5518.2384 0.194 291 5227.2384 Cubic Feet 30 0.76 4.52 0.972 1800 6010.22592 0.194 349.2 5661.02592 Cubic Feet 35 0.76 4.08 0.972 2100 6329.35296 0.194 407.4 5921.95296 Cubic Feet 40 0.76 3.74 0.972 2400 6630.75072 0.194 465.6 6165.15072 Cubic Feet 45 0.76 3.46 0.972 2700 6901.12224 0.194 523.8 6377.32224 Cubic Feet 50 0.76 3.23 0.972 3000 7158.1968 0.194 582 6576.1968 Cubic Feet 55 0.76 3.03 0.972 3300 7386.46128 0.194 640.2 6746.26128 Cubic Feet 60 0.76 2.86 0.972 3600 7605.86112 0.194 698.4 6907.46112 Cubic Feet 65 0.76 2.71 0.972 3900 7807.53168 0.194 756.6 7050.93168 Cubic Feet 70 0.76 2.59 0.972 4200 8035.79616 0.194 814.8 7220.99616 Cubic Feet 75 0.76 2.48 0.972 4500 8244.1152 0.194 873 7371.1152 Cubic Feet 80 0.76 2.38 0.972 4800 8439.13728 0.194 931.2 7507.93728 Cubic Feet 85 0.76 2.29 0.972 5100 8627.51088 0.194 989.4 7638.11088 Cubic Feet 90 0.76 2.21 0.972 5400 8815.88448 0.194 1047.6 7768.28448 Cubic Feet 95 0.76 2.13 0.972 5700 8968.79952 0.194 1105.8 7862.99952 Cubic Feet 100 0.76 2.06 0.972 6000 9130.5792 0.194 1164 7966.5792 Cubic Feet 105 0.76 2.00 0.972 6300 9307.872 0.194 1222.2 8085.672 Cubic Feet 110 0.76 1.94 0.972 6600 9458.57088 0.194 1280.4 8178.17088 Cubic Feet 115 0.76 1.88 0.972 6900 9582.67584 0.194 1338.6 8244.07584 Cubic Feet 120 0.76 1.84 0.972 7200 9786.56256 0.194 1396.8 8389.76256 Cubic Feet Outlet Structure Design OUTLET CONTROL STRUCTURE - 100-YEAR ORIFICE SIZING HEIGHT 100-YEAR 3.75 FEET Q=CoA(2gHo).5 100-year Release Rate= 0.194 CFS 100-year release rate= 0.194 cubic feet per second (includes offsite basin O1) Q = Discharge cfs Co = orifice coefficient = 0.65 Area 10-year 0.019 ft2 = 2.77 in USE 1-13/16" DIAMETER OPENING Ao = area ft2 g = gravitational constant = 32.2 ft/sec2 Ho = head above centerline of orifice Ho10 = Ho100 = Ho10 at 100-year wsel = Pro ect: Inlet ID: Gutter Geometry: Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK =ft/ft Mannin 's Rou hness Behind Curb (typically between 0.012 and 0.020) nBACK =0.015 Hei ht of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =25.0 ft Gutter Width W = 2.00 ft Street Transverse Slope S =0.045 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW =0.083 ft/ft Street Lon itudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Mannin 's Rou hness for Street Section (typically between 0.012 and 0.020) nSTREET =0.015 Minor Storm Major Storm Max. Allowable Spread for Minor & Ma or Storm TMA =25.0 25.0 f Max. Allowable Depth at Gutter Flowline for Minor & Ma or Storm dMA =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallo = SUMP SUMP cfs MHFD-Inlet, Version 5.03 (Au ust 2023 LLOWABLE CAPACITY FOR ONE-HALF OF STREET Minor & Ma or Storm (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) 302 Conifer Street - Fort Collins, CO STCB-1 MHFD-Inlet_v5.03.xlsm, STCB-1 2/13/2025, 12:46 PM Desi n Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous utter depression 'a' from above) alocal = 3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Len th of a Unit Grate o (G) = N/N/fee Width of a Unit Grate Wo = N/N/fee Open Area Ratio for a Grate (typical values 0.15-0.90)ratio = N/N/ Clo in Factor for a Sin le Grate (typical value 0.50 - 0.70) Cf (G) = N/N/ Grate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = N/N/ Grate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = N/N/ Curb Openin Information MINOR MAJOR Len th of a Unit Curb Openin o (C) = 10.00 10.00 fee Hei ht of Vertical Curb Openin in Inches Hvert = 6.00 6.00 inches Hei ht of Curb Orifice Throat in Inches Hthroat = 6.00 6.00 inches n le of Throa Theta = 63.40 63.40 de rees Side Width for Depression Pan (typically the utter width of 2 feet) W = 2.00 2.00 fee Clo in Factor for a Sin le Curb Openin (typical value 0.10) Cf (C) = 0.10 0.10 Curb Openin Weir Coefficient (typical value 2.3-3.7) Cw (C) = 3.60 3.60 Curb Openin Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate =N/A N/A ft Depth for Curb Opening Weir Equation dCurb =0.33 0.33 ft Grated Inlet Performance Reduction Factor for Lon Inlets RFGrate =N/N/ Curb Opening Performance Reduction Factor for Long Inlets RFCurb =0.93 0.93 Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =N/A N/A MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa = 8.3 8.3 cfs Inlet Capacity IS GOOD for Minor and Major Storms (>Q Peak)Q PEAK REQUIRED =1.5 5.9 cfs INLET IN A SUMP OR SAG LOCATION MHFD-Inlet, Version 5.03 (Au ust 2023 CDOT Type R Curb Opening H-VertH-Curb W Lo (C) Lo (G) Wo WP CDOT T e R Curb O enin Override Depths MHFD-Inlet_v5.03.xlsm, STCB-1 2/13/2025, 12:46 PM System Input Summary Rainfall Parameters Rainfall Return Period: 100 Rainfall Calculation Method: Formula One Hour Depth (in): 2.60 Rainfall Constant "A": 28.5 Rainfall Constant "B": 10 Rainfall Constant "C": 0.786 Rational Method Constraints Minimum Urban Runoff Coeff.: 0.20 Maximum Rural Overland Len. (ft): 500 Maximum Urban Overland Len. (ft): 300 Used UDFCD Tc. Maximum: No Sizer Constraints Minimum Sewer Size (in): 10.00 Maximum Depth to Rise Ratio: 0.90 Maximum Flow Velocity (fps): 18.0 Minimum Flow Velocity (fps): 0.0 Backwater Calculations: Tailwater Elevation (ft): 4963.50 Manhole Input Summary: Given Flow Sub Basin Information Element Name Ground Elevation (ft) Total Known Flow (cfs) Local Contribution (cfs) Drainage Area (Ac.) Runoff Coefficient 5yr Coefficient Overland Length (ft) Overland Slope (%) Gutter Length (ft) Gutter Velocity (fps) OUTFALL 1 5445.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 MH 1 SWR 1 - 1 4967.80 5.90 0.00 1.36 0.66 0.66 43.00 2.00 423.00 1.80 MH 2 SWR 2 - 1 4969.00 5.90 0.00 0.22 0.12 0.12 27.00 2.00 423.00 1.80 Manhole Output Summary: Local Contribution Total Design Flow Element Name Overland Time (min) Gutter Time (min) Basin Tc (min) Intensity (in/hr) Local Contrib (cfs) Coeff. Area Intensity (in/hr) Manhole Tc (min) Peak Flow (cfs) Comment OUTFALL 1 0.00 0.00 0.00 0.00 0.00 0.92 6.39 12.62 5.90 MH 1 SWR 1 - 1 4.14 3.92 8.06 7.62 6.84 0.92 6.39 12.62 5.90 MH 2 SWR 2 - 1 7.31 3.92 11.23 6.71 0.18 0.03 223.48 -9.75 5.90 Sewer Input Summary: Elevation Loss Coefficients Given Dimensions Element Name Sewer Length (ft) Downstream Invert (ft) Slope (%) Upstream Invert (ft) Mannings n Bend Loss Lateral Loss Cross Section Rise (ft or in) Span (ft or in) MH 1 SWR 1 - 1 58.14 4963.61 0.5 4963.90 0.011 0.03 1.00 CIRCULAR 15.00 in 15.00 in MH 2 SWR 2 - 1 16.60 4964.00 0.6 4964.10 0.011 0.05 0.25 CIRCULAR 15.00 in 15.00 in Sewer Flow Summary: Full Flow Capacity Critical Flow Normal Flow Element Name Flow (cfs) Velocity (fps) Depth (in) Velocity (fps) Depth (in) Velocity (fps) Froude Number Flow Condition Flow (cfs) Surcharged Length (ft) Comment MH 1 SWR 1 - 1 5.41 4.41 15.00 4.81 15.00 4.81 0.00 Pressurized 5.90 58.14 MH 2 SWR 2 - 1 5.94 4.84 11.79 5.70 12.19 5.52 0.93 Pressurized 5.90 16.60 A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe). If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer. If the sewer is pressurized, full flow represents the pressurized flow conditions. Sewer Sizing Summary: Existing Calculated Used Element Name Peak Flow (cfs) Cross Section Rise Span Rise Span Rise Span Area (ft^2) Comment MH 1 SWR 1 - 1 5.90 CIRCULAR 15.00 in 15.00 in 15.00 in 15.00 in 15.00 in 15.00 in 1.23 MH 2 SWR 2 - 1 5.90 CIRCULAR 15.00 in 15.00 in 15.00 in 15.00 in 15.00 in 15.00 in 1.23 Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size. Sewer sizes should not decrease downstream. All hydraulics where calculated using the 'Used' parameters. Grade Line Summary: Tailwater Elevation (ft): 4963.50 Invert Elev. Downstream Manhole Losses HGL EGL Element Name Downstream (ft) Upstream (ft) Bend Loss (ft) Lateral Loss (ft) Downstream (ft) Upstream (ft) Downstream (ft) Friction Loss (ft) Upstream (ft) MH 1 SWR 1 - 1 4963.61 4963.90 0.00 0.00 4964.86 4965.20 4965.22 0.35 4965.56 MH 2 SWR 2 - 1 4964.00 4964.10 0.02 0.27 4965.49 4965.59 4965.85 0.10 4965.95 Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a sewer. Bend loss = Bend K * V_fi ^ 2/(2*g) Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g). Friction loss is always Upstream EGL - Downstream EGL. Excavation Estimate: The trench side slope is 1.0 ft/ft The minimum trench width is 2.00 ft Downstream Upstream Element Name Length (ft) Wall (in) Bedding (in) Bottom Width (ft) Top Width (ft) Trench Depth (ft) Cover (ft) Top Width (ft) Trench Depth (ft) Cover (ft) Volume (cu. yd) Comment MH 1 SWR 1 - 1 58.14 2.25 4.00 4.63 963.53 482.41 480.45 7.55 4.42 2.46 249925.67 MH 2 SWR 2 - 1 16.60 2.25 4.00 4.63 7.35 4.32 2.36 9.55 5.42 3.46 16.29 Total earth volume for sewer trenches = 249942 cubic yards. The trench was estimated to have a bottom width equal to the outer pipe diameter plus 36 inches. If the calculated width of the trench bottom is less than the minimum acceptable width, the minimum acceptable width was used. The sewer wall thickness is equal to: (equivalent diameter in inches/12)+1 inches The sewer bedding thickness is equal to: o Four inches for pipes less than 33 inches. o Six inches for pipes less than 60 inches. C. MAP POCKET AAppppeennddiixx CC –– MMAAPP PPOOCCKKEE Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/6/2024 Page 1 of 4 44 9 4 6 6 0 44 9 4 6 7 0 44 9 4 6 8 0 44 9 4 6 9 0 44 9 4 7 0 0 44 9 4 7 1 0 44 9 4 7 2 0 44 9 4 7 3 0 44 9 4 7 4 0 44 9 4 6 6 0 44 9 4 6 7 0 44 9 4 6 8 0 44 9 4 6 9 0 44 9 4 7 0 0 44 9 4 7 1 0 44 9 4 7 2 0 44 9 4 7 3 0 44 9 4 7 4 0 493930 493940 493950 493960 493970 493980 493990 494000 494010 494020 494030 494040 494050 494060 493930 493940 493950 493960 493970 493980 493990 494000 494010 494020 494030 494040 494050 494060 40° 36' 12'' N 10 5 ° 4 ' 1 8 ' ' W 40° 36' 12'' N 10 5 ° 4 ' 1 2 ' ' W 40° 36' 9'' N 10 5 ° 4 ' 1 8 ' ' W 40° 36' 9'' N 10 5 ° 4 ' 1 2 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 30 60 120 180 Feet 0 5 10 20 30 Meters Map Scale: 1:654 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 19, Aug 29, 2024 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 2, 2021—Aug 25, 2021 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/6/2024 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 22 Caruso clay loam, 0 to 1 percent slope D 1.5 98.9% 73 Nunn clay loam, 0 to 1 percent slopes C 0.0 1.1% Totals for Area of Interest 1.5 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/6/2024 Page 3 of 4 National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or Depth Zone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to Levee Zone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood Hazard Zone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 11/15/2024 at 1:14 AM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 105°4'37"W 40°36'24"N 105°4'W 40°35'57"N Basemap Imagery Source: USGS National Map 2023 ST ST ST ST ST ST ST ST ST ST ST ST G G G G G G D S S D STORM MANHOLE WITH TYPE R INTAKE RIM = 4966.49' FL (S) 24" RCP = 4963.83' STORM MANHOLE RIM = 4968.27' FL (N) 24" RCP = 4964.16' FL (S) 24" RCP = 4964.07' FL (E) 18" RCP = 4964.16' FL (W) 18" RCP = 4964.17'ST STORM DRAIN INLET RIM = 4967.73' FL (W) 18" RCP = 4965.28' NORTHEAST CORNER OF LOT 13 REPLAT (NO.1) OF EVERGREEN PARK FOUND #4 REBAR VACANT LOT OWNER(S): OLEADA CONIFER LLC 5' 16' 16' UTILITY & DRAINAGE EASEMENT (BOOK 1597 PAGE 128/ RECEPTION NO. 85405) 6' UTILITY EASEMENT (BOOK 1597 PAGE 128/ RECEPTION NO. 85405) 6' 6' UTILITY EASEMENT (BOOK 1597 PAGE 128/ RECEPTION NO. 85405) 6' ZONING: COMMUNITY COMMERCIAL - NORTH COLLEGE DISTRICT 49 7 0 4969 49 6 5 49 6 5 49 6 949 6 9 4967 4968 49 6 9 4970 4970 4969 4968 49 6 8 49 6 7 49 6 6 49 6 4 36" RCP PIPE FL = 4962.58' 36" RCP PIPE FL = 4962.76' PORTION OF WEST 1/2 OF SECTION 01-T7N-R69W (RECEPTION NO. 20210016924) OWNER(S): LONG CREEK TRUST ZONING: COMMUNITY COMMERCIAL - NORTH COLLEGE DISTRICT SOUTHEAST CORNER OF LOT 13 REPLAT (NO.1) OF EVERGREEN PARK FOUND #4 REBAR 36" RCP PIPE FL = 4962.78' 58.38' FL-FL CONIFER STREET 80.00' R.O.W. 80 . 0 0 ' R . O . W . 59 . 7 2 ' FL - F L E1 0.15 0.27 0.32 E2 1.04 0.24 0.29 16.00' UTILITY ESMT. BL U E S P R U C E D R I V E A BASIN DESIGNATION EXISTINGD SUMMARY RUNOFF TABLE CONTRIBUTING DESIGN PT BASINS / AREA (acres)RUNOFF (cfs) 2-YEAR 100-YEAR PEAK RUNOFF (cfs) A BASIN AREA 2 YR COMPOSITE 'C' 100YR COMPOSITE 'C' DESIGN POINT BASIN LIMITS 0.09 0.36 TC CALCULATIONS LEGEND 0.54 2.29 0.63 2.65 E1/0.15 E2/1.04 TOTAL EX/1.19 38 8 S a n t a F e D r i v e D e n v e r , C O 8 0 2 2 3 DE N V E R RJP RJP SEL 03/21/2025 CURRENT.DWG PARIKH MZ . CO L O R A D O NA NA LA R I M E R FO R T C O L L I N S 30 2 C O N I F E R S T R E E T 2595 PONDEROSA ROAD FRANKTOWN, CO 80116 720.384.7661 Phone rpalmer@strategicls.net Robert J. Palmer, PE President 03/21/2025 23 OF 30 EXISTING DRAINAGE PLAN Know what's below. before you dig.Call R ST ST ST ST ST ST ST ST ST ST ST ST G G G G G G C CABLE CABLE VAULT CABLE CABLE VAULT CABLE VAULT ELEC ELEC D S S D STORM MANHOLE WITH TYPE R INTAKE RIM = 4966.49' FL (S) 24" RCP = 4963.83' STORM MANHOLE RIM = 4968.27' FL (N) 24" RCP = 4964.16' FL (S) 24" RCP = 4964.07' FL (E) 18" RCP = 4964.16' FL (W) 18" RCP = 4964.17'ST STORM DRAIN INLET RIM = 4967.73' FL (W) 18" RCP = 4965.28' 49 7 0 4969 49 6 5 49 6 5 49 6 949 6 9 4967 4968 49 6 9 4970 4970 4969 4968 49 6 8 49 6 7 49 6 6 49 6 4 36" RCP PIPE FL = 4962.58' 36" RCP PIPE FL = 4962.76' PORTION OF WEST 1/2 OF SECTION 01-T7N-R69W (RECEPTION NO. 20210016924) 36" RCP PIPE FL = 4962.78' 50' NATURAL HABITAT BUFFER ZONE 15" CONC. FES INV.=4963.50 W/TYPE L SOIL RIPRAP 1.75' DEEP 15" RCP @0.50% STCB-1 10' TYPE R GRATE=4968.20 INV. IN=496.20 INV. OUT=4964.10 OCS 5'X6" ID RIM=4968.60 INV. IN (W)=4965.50 INV. IN (S)=4965.50 INV. OUT=4963.8020' L.F. 15" RCP STUB INV.=4966.26 OBSV. WELL W/TRAFFIC LID INV.=4966.50 OBSV. WELL W/ TRAFFIC LID INV.=4966.50 OBSV. WELL W/TRAFFIC LID INV.=4965.50 OBSV. WELL W/ TRAFFIC LID INV.=4966.50 4" SLOTTED PIPE S=0.50% 4" SLOTTED PIPE S=0.50% 6" SLOTTED PIPE S=0.50% 4" SLOTTED PIPE S=0.50% 14'5. 5 0 ' 4"X4"X6" TEE 4" SLOTTED PIPE S=0.50%4"X4"X4" TEE FFE=4969.50 58.38' FL-FL CONIFER STREET 80.00' R.O.W. 80 . 0 0 ' R . O . W . 59 . 7 2 ' FL - F L 4969 4968 49 6 8 4969 A 0.92 0.69 0.76 B 0.20 0.43 0.48 9.00' UTILITY ESMT 9. 0 0 ' UT I L I T Y ES M T . B 0.02 0.20 0.25 16.00' UTILITY ESMT. BL U E S P R U C E D R I V E 49 6 9 4966.15fl 4966.13fl 4966.63tc 4966.70w4966.22w 4966.00fl 4966.23fl 4966.25fl 4966.75tc 4966.82w 4966.30w 4969.00g 4969.00g 4968.00g 4967.00g 4969.68g 4969.17P 4969.17P 4969.129 4969.129 4969.00W 4969.00W 4968.97W 4968.97W 4968.50fl 4967.16fl 4967.25fl 4968.00fl 4968.70fl 4968.60fl 4968.60fl 4968.65fl 4968.70fl 4968.85fl 4968.87fl 4969.42w 4969.40W 4969.40W 4968.90FL 4968.90FL 4968.60P 4968.60P 4968.50FL 4969.00G4970.00G 4970.90g 4970.00g 4968.90fl 4968.85fl 4968.82fl 4968.50fl 4968.45fl 4968.30fl 4968.55fl 4968.55fl 4968.00fl 4969.30g 4968.50fl 4968.90fl 4968.80p 4968.10fl 4968.00fl 4968.35fl 4968.20fl 4968.70fl 4968.70fl 4968.70fl 4968.65fl4968.50fl 4968.50fl 4968.50fl 4968.50fl 4969.50fl 4968.80fl 4968.80fl 4968.80fl 4969.25fl 4968.80fl 4968.50fl 4968.30g 4968.50g 4968.27fl 4968.34w 4968.34fl 4968.37fl 4968.87tc 4968.94w 4968.24fl 4968.74tc 4968.81w 4968.80fl 4968.90fl 4969.00fl 4969.00fl 4968.80fl 4968.80fl 4968.80fl 4968.80fl 4968.50g 4968.50g 4968.50g 4968.40fl 4967.90fl 4967.55fl 4967.15fl 4967.05fl 4969.05p 4969.05p 4969.05p 4969.05p 4969.05p 4969.05p 4969.05p4969.05p 4969.05p 4969.05p 4969.05p 4969.05p4969.05p 4969.05p 4969.05p4969.05p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4968.57w 4967.00w 4966.95w 4966.95w 4966.95w 4966.85w 4966.85w 4967.19w 4967.18w 4967.37w 4967.33w4967.70w 4967.65w 4967.65w 4967.72w 4967.83w 4968.22w 4968.00W 4969.45w 4969.45w 4969.45w 4969.45w 4968.10w 4968.05w 4968.50gt 4966.50gt 4966.57w 4968.77w 4968.75w 4968.97w 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.15p 4969.05p 4969.05p 4969.05p 4969.05p4969.05p 4969.05p 4969.05p 4969.00p 4969.00p 4969.00p4969.00p 4969.00p 4969.00p4969.00p 4969.00p4969.00p 4968.95p 4968.95p 4968.95p 4969.40w 4969.40w 4968.90fl 4968.50p 4969.45w 4969.42w 4969.40w 4969.40w 4968.90w 4969.45w 4968.95w 4968.90w 4969.40w4968.80fl 4969.31w4969.28w 4968.81w 4968.80w 4968.70fl 4968.50fl 4969.15p 4968.10TW 4967.0BW 10" PVC @ 0.50% 4968.50p 4968.80p 4968.80p 4968.90fl 4968.90fl 4968.50p 4968.50p4968.50p 4968.50p 4968.50p 4969.00p 4969.00p 4969.009 4969.009 4968.57w 4968.50w 4969.45w 4969.45w 4968.50TW 4968.00BW 4968.41w 4967.81w 4968.20w 4969.15p 4968.60p 4969 A BASIN DESIGNATION PROPOSED SUMMARY RUNOFF TABLE CONTRIBUTING DESIGN PT BASINS / AREA (acres)RUNOFF (cfs) 2-YEAR 100-YEAR PEAK RUNOFF (cfs) ABASIN AREA 2 YR COMPOSITE 'C' 100YR COMPOSITE 'C' DESIGN POINT BASIN LIMITS 1.53 5.90 TC CALCULATIONS LEGEND 0.19 0.73 0.01 0.04 A/0.972 B/0.195 C/0.01929 TOT SITE/1.19 1.69 6.50 DETENTION POND A WATER SURFACE ELEVATION (FEET) VOLUME (CUBIC FEET) NOTES WATER QUALITY CAPTURE VOLUME (WQCV) 100-YEAR DETENTION (TOTAL STORAGE) DATE: 02/14/2025 7264966.10 RELEASE RATE (CFS) 0.017 CFS 6,825 0.97CFS4967.75 POROUS PAVERS REQUIRED PROVIDED 726 6,825 MAX.PROVIDED 0.017 CFS 0.97 CFS POROUS PAVERS 38 8 S a n t a F e D r i v e D e n v e r , C O 8 0 2 2 3 DE N V E R RJP RJP SEL 03/21/2025 CURRENT.DWG PARIKH MZ . CO L O R A D O NA NA LA R I M E R FO R T C O L L I N S 30 2 C O N I F E R S T R E E T 2595 PONDEROSA ROAD FRANKTOWN, CO 80116 720.384.7661 Phone rpalmer@strategicls.net Robert J. Palmer, PE President 03/21/2025 24 OF 30 PROPOSED DRAINAGE PLAN Know what's below. before you dig.Call R 38 8 S a n t a F e D r i v e D e n v e r , C O 8 0 2 2 3 DE N V E R RJP RJP SEL 03/21/2025 CURRENT.DWG PARIKH MZ . CO L O R A D O NA NA LA R I M E R FO R T C O L L I N S 30 2 C O N I F E R S T R E E T 2595 PONDEROSA ROAD FRANKTOWN, CO 80116 720.384.7661 Phone rpalmer@strategicls.net Robert J. Palmer, PE President 03/21/2025 25 OF 30 DRAINAGE DETAILS 2" L CHANNEL US FILTER STAINLESS STEEL WELL-SCREEN (OR EQUAL) TRASH RACK DESIGN SPECIFICATIONS TABLE A: WATER QUALITY TRASH RACK 1/5"0.139"#93 VEE 0.31"TE 0.074"X0.5' SUPPORT CARBON STELL FRAME TYPE TOTAL SCREEN THICKNESS SUPPORT ROD, ON CENTER, SPACING SUPPORT ROD TYPE SCREEN #93 VEE WIRE SLOT OPENING MAX WIDTH OF OPENING RODS @ 1" O.C.(DIAG) 6.00' 5. 0 0 ' 2' ACCESS MANHOLE 2' ACCESS MANHOLE 4" SLOTTED UNDER DRAIN 4" SLOTTED PIPE UNDER DRAIN 15" CLS III RCP TO OUTFALL 15" RCP CLS III TO TYPE R INLET 15" CLASS III RCP TO CHANNEL OUTFALL ORIFICE WALL/OVERFLOW ELEV.=4968.00 4967.75 100-YEAR WSEL 4964.00 100-YEAR ORIFICE PRE-CAST VAULT STRUCTURE CONTRACTOR TO SUBMIT SHOP DRAWINGS TO ENGINEER FOR APPROVAL PRIOR TO ORDERING ORIFICE DIAMETER=1-13/16" ORIFICE PLATE W/WELL SCREEN TRASH RACK 19" 4. 0 0 ' 1/ 4 " T H I C K G A L V A N I Z E D S T E E L P L A T E 12" 1/4" BOLT TYP. TOP OF PLATE ELEVATION ELEV = 4968.00 4964.00(PLATE BOTTOM) ORIFICE PLATE 1-13/16" ORIFICE 4964.00 (WQ ORIFICE) INV, OUT=4963.80 DETENTION POND OUTLET CONTROL STRUCTURE (OCS) 4" SLOTTED PIPE INV. IN=49665.75 15" RCP INV. IN=4965.50 WEST AND SOUTH 15" RCP CLS III TO TYPE R INLET 15" RCP INV. IN=4965.50 WEST AND SOUTH 1"TRASH RACK 38 8 S a n t a F e D r i v e D e n v e r , C O 8 0 2 2 3 DE N V E R RJP RJP SEL 03/21/2025 CURRENT.DWG PARIKH MZ . CO L O R A D O NA NA LA R I M E R FO R T C O L L I N S 30 2 C O N I F E R S T R E E T 2595 PONDEROSA ROAD FRANKTOWN, CO 80116 720.384.7661 Phone rpalmer@strategicls.net Robert J. Palmer, PE President 03/21/2025 26 OF 30 DRAINAGE DETAILS POROUS PAVER DETENTION SECTION 23.5" 38 8 S a n t a F e D r i v e D e n v e r , C O 8 0 2 2 3 DE N V E R RJP RJP SEL 03/21/2025 CURRENT.DWG PARIKH MZ . CO L O R A D O NA NA LA R I M E R FO R T C O L L I N S 30 2 C O N I F E R S T R E E T 2595 PONDEROSA ROAD FRANKTOWN, CO 80116 720.384.7661 Phone rpalmer@strategicls.net Robert J. Palmer, PE President 03/21/2025 27 OF 30 DRAINAGE DETAILS NOTE: DOWNSPOUT CONNECTION CLEANOUT COVER DETAIL FOR CLEANOUTS LARGER THAN 6" DIAMETER REQUIRED GRATE