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Home My WebLink AboutFAITH FAMILY HOSPITALITY TRANSITIONAL HOUSE - FDP - FDP170027 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTDRAINAGE REPORT FOR Faith Family 317-321 Sherwood Street Fort Collins, CO 80521 Prepared for: Kenny Lee Architecture Group Inc. 209 E 4 th Street Loveland, CO 80537 Prepared by: www.coffey-engineering.com 4045 St Cloud Street, Suite 180 Loveland, Colorado 80538 (970) 622-2095 CES Project No: 7040-007 Date: August 4, 2017 September 6, 2017 Faith Family FINAL DRAINAGE REPORT ENGINEER’S CERTIFICATION I hereby certify that this Final Drainage Report for the design of stormwater management facilities for the Faith Family Project was prepared by me, or under my direct supervision, in accordance with the provisions of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards for the owners thereof. Cody Geisendorfer, P.E. Registered Professional Engineer State of Colorado No. 41326 I. Table of Contents I. GENERAL LOCATION AND DESCRIPTION ......................................... 1 A. Location .................................................................................................................... 1 B. Description of Property ........................................................................................... 1 II. DRAINAGE BASINS AND SUB-BASINS .................................................. 2 A. Major Basin Description ......................................................................................... 2 B. Sub-Basin Description ............................................................................................. 2 III. DRAINAGE CRITERIA ............................................................................... 3 A. Regulations ............................................................................................................... 3 B. Implementation of the “Four Step Process” .......................................................... 3 C. Development Criteria Reference and Constraints ................................................ 4 D. Hydrological Criteria............................................................................................... 4 E. Hydraulic Criteria ................................................................................................... 5 F. Modifications of Criteria ......................................................................................... 5 IV. DRAINAGE FACILITY DESIGN ............................................................... 5 A. General Concept....................................................................................................... 5 B. Specific Details ......................................................................................................... 6 V. CONCLUSIONS ............................................................................................. 6 A. Compliance with Standards .................................................................................... 6 B. Drainage Concept..................................................................................................... 7 VI. REFERENCES ............................................................................................... 7 VII. APPENDICES A. Hydrologic Computations Vicinity Map Fort Collins Flood Map FEMA Firm Panel 08069C0979H USGS Soil Map Soilogic Soils Report Fort Collins Rainfall Intensity Curve Fort Collins Rainfall Intensity Table Table RO-3 Recommended Percentage Imperviousness Values Rational Method Calculated Composite C Tables Rational Method Calculated Imperviousness Rational Method Calculated Flows B. Hydraulic Computations Fort Collins Modified FFA Method Infiltration Calculation C. Map Pocket Drainage Plan I. GENERAL LOCATION AND DESCRIPTION A. Location The proposed site is located in the southeast quarter (NE ¼) of Section 11, Township 7 North, Range 69 West of the 6th P.M. in Larimer County, Colorado. Specifically, the property is located on Sherwood Street between Magnolia Street and Olive Street. The property address is 317-321 Sherwood Street, Fort Collins, Colorado, 80521. (Please see the vicinity map located in the Appendix A). B. Description of Property The property’s parcel number are 9711420904 and 9711420903. The site is located on Lots 3 and 4, Block 73 City of Fort Collins and is currently 0.436 acres of residential land surrounded by the residential lots to the north and south, an alley to the west, and Sherwood Street to the east. The site can be accessed from Sherwood Street and the existing alley. Two gravel patches provide on-site parking and the site can be accessed from the alley. The existing property is a residential building with no occupants located in the central portion of the Old Town Basin. The site drains east to Sherwood Street through a drainage channel along the northern property line. Sherwood Street drains south to the existing inlet, where it is conveyed to the Poudre River. Runoff from the alley flows south to West Magnolia Street, where is flows east to an existing storm inlet. There are generally no offsite flows that drain toward the property. The site is within the city- regulated 100-year Old Town floodplain. More specifically, the entire site is located within the City of Fort Collins Flood Fringe. The City of Fort Collins Floodway encompasses all of Sherwood Street and West Magnolia Street and extends to the back of the sidewalk. The site is located with the FEMA Firm Panel 08069C0979H. (see City Flood Risk Map and the FEMA Firm Panel in Appendix A). According to the NRCS soils map survey, the native soils consist of Fort Collins Loam, which is a Type “C” soils. These soils 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. There are no irrigation facilities located within the proposed site area. The existing building will be remodeled to serve as temporary housing for homeless families. The proposed development will consist of the construction of an off-street permeable paver parking lot that will act as a parking for the residents and employees of Faith Family. The permeable paver parking lot will have an underdrain network of 4” perforated that drains into an 8’ dry well. The existing gravel alley will also be paved with asphalt from the northern property line to Magnolia Street. II. DRAINAGE BASINS AND SUB-BASINS A. Major Basin Description The proposed site is located within the Old Town Basin. The Old Town Drainage Basin is located in north-central Fort Collins. The basin has a drainage area of approximately 2,120 acres, including approximately 400 acres of the Colorado State University campus. The entire basin is urbanized, with some development dating back to the late 1800s. Generally, the basin drains from west to east. The Old Town Basin receives some runoff water from the Canal Importation Basin directly west of Old Town. Most of the water from Old Town drains to the Poudre River, just to the east. B. Sub-Basin Description Historically, most of the site drains east to Sherwood Street. The developed site is delineated into two sub-basins, with underground detention designed to provide the required water quality capture volume. Sub-basin B1, (0.074 acres), consists of an existing shed to be removed and gravel parking lot. The existing gravel patch is to be constructed into an asphalt parking lot with permeable paver parking spots. Rainfall travels via overland flow from east to west, into a permeable paver system. Once the flow enters the paver system, it is conveyed to an 8’ deep dry well. The flow from the site eventually infiltrates into the ground surface. Sub-basin B2, (0.362 acres), consists of an existing building, landscaped area, and concrete walkways. The addition of the dry well and replacing the sidewalk chase are the only proposed changes to sub-basin B2. Rainfall travels via overland flow to a grass swale, where it will be conveyed to a concrete drainage channel. Once the flow is concentrated into the channel, it is conveyed to the flowline Sherwood Street. The flow from the site eventually drains into the Poudre River. Currently, flows from the alley enter the site from the west. The proposed curb and gutter will prevent off-site flows from entering the site. III. DRAINAGE CRITERIA A. Regulations Drainage design criteria specified in the City of Fort Collins Storm Drainage Design Criteria and Construction Standards manual (FCSDCM) and the Urban Storm Drainage Criteria Manual, Volume 3 by the Urban Drainage and Flood Control District (UDFCD) have been referenced in the preparation of this study. Low Impact Development (LID) requirements are required on all new or redeveloping property which includes sites required to be brought into compliance with the Land Use Code. These require a higher degree of water quality treatment with one of the two following options: a) 50% of the newly added or modified impervious area must be treated by LID techniques and 25% of new paved areas must be pervious or b) 75% of all newly added or modified impervious area must be treated by LID techniques. For this site, we are following option a). The site improvements propose a 2,100 ft 2 asphalt parking lot, 850 ft 2 of which will be permeable pavers. 100% percent of the flow from the impervious area will be directed toward the pavers sections, which make up 40% of the proposed parking lot. B. Implementation of the “Four Step Process” The overall stormwater management strategy employed with this parking lot and alley improvements utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices. The first consideration taken in trying to reduce the stormwater impacts of this development is the site selection itself. By selecting a site with historically undetained runoff, the burden of development will be significantly less with underground detention. Also, permeable pavers are used to reduce the area of impervious surfaces, reducing the effects of imperviousness. Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with Slow Release. Demolishing the existing shed, adding landscaped areas, and constructing permeable pavers will cause stormwater runoff to increase from the site. The runoff will be released through the bottom of a dry well and paver sub-base. The primary water quality will occur in the permeable pavers and dry well. Refer to the map pocket for permeable paver details and cross-sections. The permeable pavers will increase water quality and promote infiltration. Water quality treatment for 50% of the site is provided for in the Udall Natural Area water treatment facility. Step 3 – Stabilize Drainageways. The Poudre River is the governing drainageway for the proposed site. The proposed project indirectly helps achieve a better stabilized drainageway nonetheless. By improving the water quality and increasing infiltration, the likelihood of bed and bank erosion from this site is greatly reduced. Step 4 – Implement Site Specific and Other Source Control BMPs. The Family Faith site contains a plethora of source control BMPs. Permeable Pavement Systems: Flow from the parking lot will directly flow into the void area of the pavers avoiding any extra pollutant-flow contact time. The sub-base of the pavers will work to filter out any pollutants. Dry Well: Flow entering the dry well will slowly infiltrate into the soil, after filtering out any pollutants. C. Development Criteria Reference and Constraints The criteria used as the basis for analysis and design of stormwater management improvements for this site are those found in the references cited. To the knowledge of the author, there are no other capital drainage improvements planned for this portion of the site; aside from those referred to above, that would constrain or otherwise influence the design of the stormwater improvements for this site. D. Hydrological Criteria Stormwater runoff from the respective sub-basins of the site is analyzed for storms with 2- year and 100-year return frequencies. Due to the relatively small aggregate area of the tributary drainage sub-basins, the Rational Method was chosen for use in the design of the stormwater management improvements. The Rational Method provides that: Q = CIA, where: Q = Design flow in cubic feet per second (cfs) C = Coefficient of runoff for the area under consideration I = Rainfall intensity for the design storm duration (in/hr) A = Area of the drainage sub-basin under consideration (ac) Peak flows were calculated using the Rational Method for the 2-year and 100-year storm events. This software uses the local 1-hour rainfall depth and Fort Collins rainfall intensities developed calculate rainfall intensities as a function of the time of concentration. These values were obtained by the City of Fort Collins Rainfall Intensity-Duration- Frequency (IDF) curve/table; Figure 3-1 and Table 3-1a, and can be found in the Appendix. Additionally, per City of Fort Collins, the coefficients have been multiplied by the appropriate storm factors. Percent imperviousness values were taken from Table RO-3, Recommended Percentage Imperviousness Values, UDCM (See Appendix). Soils of hydrologic soil type “C” dominate the site. Onsite runoff was calculated to determine the runoff differential between existing and developed conditions for use in sizing the WQCV as required by the FCSDM. The hydrologic basin parameters and runoff rates are included in the Appendices and include quantification of the allowable volume reduction. On-site detention is not required, but permeable pavers have built in detention within the sub-base. The permeable paver sub-base is separated into two layers of subbase, a 4” layer of #57 base and a 15” layer of #2 base. The detention volume of the system can be found using the following equation: Volume = (area of pavers) X (depth of #2 sub-base) X (void space). The sub-base of the permeable pavers is assumed to have a void space of 30%. The total area of permeable pavers is 850 ft 2 , therefore the detention volume of the sub-base is 318 ft 3 . The storage volume (V = πr 2 h) in the 8’ dry well is 25 ft 3 . The total detention volume for the site is 343 ft 3 . Detention is being utilized in the sub-base of the pavers to prevent surface ponding. The design worksheets included in the Appendices to this Final Drainage Report present documentation of the hydrologic calculations for the on-site storm drainage systems. E. Hydraulic Criteria Within this development, all runoff will be conveyed on the surface, initially as sheet flow and subsequently as concentrated flow in shallow pans and gutters. The assessment of required capacity and the sizing of the respective components of the drainage system are based on the anticipated runoff from the 100-year storm event. F. Modifications of Criteria There are no modifications or variances requested in connection with the design of the stormwater management for the Faith Family site development. IV. DRAINAGE FACILITY DESIGN A. General Concept The storm drainage system is designed to safely convey developed storm flows by sheet flow, concentrated pan, and gutter flow to the street flowlines. The design worksheets included in the Appendices to this Final Drainage Report present details of the hydrologic and hydraulic calculations pertinent to the design of the on-site storm drainage system. A drainage plan, showing the proposed development of the site and developed drainage patterns is included in the map pocket following the Appendices. B. Specific Details There are a number of collection and conveyance scenarios within the drainage regime associated with this development. The respective scenarios are described below. Sub-basin B1, (0.074 acres), consists of a permeable parking lot and landscaped areas. The runoff created by a 100-Year event is increased from 0.47 cfs to 0.50 cfs with the proposed improvements to the parking lot. Runoff will infiltrate through the permeable pavers to a network of 4” perforated PVC pipes and drains into a proposed 8’ dry well. The well- draining soil was encountered 22’ below ground surface. The water table was encountered 15.5’ below ground surface. Because the well-draining soils are below the water table, it is impractical to construct the dry well to well-draining soils. The 8’ of depth dry well and permeable pavers sub-base provides adequate infiltration rates for the small basin area. Flows in excess of the 100-year event will be conveyed east to the existing concrete drainage channel on the north side of the site. (See Appendix B for calculations.) Sub-basin B2, (0.362 acres), consists of an existing building, landscaped area, and concrete walkways. Rainfall travels via overland flow to a grass swale, where it will be conveyed to a concrete drainage channel. Once the flow is concentrated into the channel, it is conveyed to the flowline Sherwood Street. The flow from the site eventually drains into the Poudre River. There is no change in sub-basin B2 from the existing condition. Alley, (0.094 acres), consists of an existing gravel alley that is to be paved with asphalt. The alley design follows Fort Collins Alley Option B (drainage to one side), with a roll-over curb. The alley flows north to south, and has a slope of 0.5%. The high point is located at the northern property line of the site to prevent developed flows entering the neighbor’s property to the north. The access to the alley will be reconstructed to match the proposed flowline of the alley. The undeveloped portion of the alley follows existing drainage patterns, flowing north to the flowline of Olive Street. V. CONCLUSIONS A. Compliance with Standards The drainage design for the Faith Family site is in compliance with the requirements of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards Manual as well as the City’s floodplain regulations. The criteria and recommendations of the Urban Storm Drainage Criteria Manual are also reflected in the design of the drainage systems. B. Drainage Concept The drainage design for the Faith Family will be adequate to safely convey onsite flows through the development. Development of the site, as proposed, should have a beneficial impact on water quality in downstream drainage facilities and drainage ways by reducing and delaying the initial discharge of runoff from the site such that sediments and other potential pollutants typically carried by this first flush are removed from the flow. The proposed drainage improvements cause no adverse impact to the adjacent properties. VI. REFERENCES “City of Fort Collins Stormwater Criteria Manual”, City of Fort Collins, Adopted December 2011 “City of Fort Collins Municipal Code”, Chapter 10 – Flood Protection and Prevention City of Fort Collins, 1987 Urban Storm Drainage Criteria Manual, Volumes 1, 2, and 3, Urban Drainage and Flood Control District, April 2008 APPENDIX A: Hydrologic Computations Vicinity Map Fort Collins Flood Map FEMA Firm Panel 08069C0979H USGS Soil Map Soilogic Soils Report Fort Collins Rainfall Intensity Curve Fort Collins Rainfall Intensity Table Table RO-3 Recommended Percentage Imperviousness Values Rational Method Calculated Runoff Coefficients Rational Method Calculated Imperviousness Rational Method Calculated Flows Rational Method Calculated Composite C Tables Rational Method Calculated Imperviousness Rational Method Calculated Flows Soilogic, Inc. 3050 67th Avenue, Suite 200  Greeley, CO 80634  (970) 535-6144 P.O. Box 1121  Hayden, CO 81639  (970) 276-2087 March 23, 2017 Quality Engineering, LLC 2637 Midpoint Drive, Suite E Fort Collins, Colorado 80234 Attn: Ms. Lisa Denke, P.E. Re: Geotechnical Subsurface Exploration 317-321 Sherwood Street Dry Well Fort Collins, Colorado Soilogic Project # 17-1053 Ms. Denke: Soilogic, Inc. (Soilogic) personnel have completed the geotechnical subsurface exploration you requested for the proposed dry well to be constructed at 317-321 Sherwood Street in Fort Collins, Colorado. Results of our subsurface exploration and estimated permeability rates are included with this report. To develop subsurface information in the proposed dry well area, one (1) soil boring was extended to a depth of approximately 25 feet below present site grade. The boring location was established in the field by Soilogic personnel based on a provided site plan, the accessibility of the site and by pacing and estimating angles and distances from identifiable site references. The boring location should be considered accurate only to the degree implied by the methods used to make the field measurements. A diagram indicating the approximate boring location is included with this report. A graphic log of the auger boring is also included. The test hole was advanced using 4-inch diameter continuous flight auger powered by a truck-mounted CME-45 drill rig. Samples of the subsurface materials were obtained at regular intervals using California barrel sampling procedures in general accordance with ASTM specification D-1586. As part of the D-1586 sampling procedure, the standard sampling barrel is driven into the substrata using a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the sampler a distance of 12 inches is recorded and helpful in estimating the consistency or relative density of the soils and//or bedrock encountered. In the California barrel sampling procedure, lesser Geotechnical Subsurface Exploration Report Wells Fargo Parking Lot 112 West Magnolia Street, Fort Collins, Colorado Soilogic # 16-1181 2 disturbed samples are obtained in removable brass liners. Samples of the subsurface materials obtained in the field were sealed and returned to the laboratory for further evaluation, classification and testing. The samples collected were visually and tactually evaluated in the laboratory to determine soil type classification and associated estimated permeability rates. Permeability rates are outlined below in Table 1 and on the attached boring log. SUBSURFACE CONDITIONS The subsurface materials encountered in the completed site boring can be summarized as follows. Approximately 6 inches of gravel surfacing was encountered at the surface at the boring location. The gravel surfacing was underlain by brown silty sand and gravel. The sand and gravel extended to a depth of approximately 18 inches below ground surface and was underlain by light brown, silty lean clay/sandy silt. The silty lean clay/sandy silt extended to a depth of approximately 9 feet below ground surface and was underlain by tan to light reddish brown sandy lean clay. The lean clay extended to a depth of approximately 18 feet below ground surface and was underlain by light reddish brown sandy lean to fat clay. The lean to fat clay extended to a depth of approximately 22 feet below ground surface and was underlain by reddish brown sand and gravel. The sand and gravel extended to the bottom of boring B-1 at a depth of approximately 25 feet below present site grade. Groundwater was encountered in the completed site boring at a depth of approximately 15½ feet below ground surface at the time of drilling. When checked about 3 days after completion of drilling, groundwater levels remained unchanged. Groundwater levels will vary seasonally and over time based on weather conditions, site development, irrigation practices and other hydrologic conditions. Perched and/or trapped groundwater conditions may also be encountered at times throughout the year. Perched water is commonly encountered in soils overlying less permeable soil layers and/or bedrock. Trapped water is typically encountered within more permeable zones of layered soil and bedrock systems. The location and amount of perched/trapped water can also vary over time. Geotechnical Subsurface Exploration Report Wells Fargo Parking Lot 112 West Magnolia Street, Fort Collins, Colorado Soilogic # 16-1181 3 TABLE 1: SUMMARY OF ESTIMATED PERMEABILITY RATES Depth (ft) Soil Type Estimated Permeability Rate (cm/sec) 1½-9 Silty Lean Clay/Sandy Silt 0.0006 9-18 Sandy Lean Clay 0.0004 18-22 Sandy Lean to Fat Clay 0.0002 22-25 Sand and Gravel 0.008 We appreciate the opportunity to be of service to you on this project. If we can be of further service to you in any way or if you have any questions concerning the enclosed information, please do not hesitate to contact us. Very Truly Yours, Soilogic, Inc. Reviewed by: Wolf von Carlowitz, P.E. Darrel DiCarlo, P.E. Principal Engineer Senior Project Engineer 36746 44271 LOG OF BORING B-1 1/1 CME 45 4" CFA Automatic CP/ZG Swell % Passing SOIL DESCRIPTION Depth "N" MC DD Pressure # 200 Sieve (ft) (%) (pcf) (psf) LL PI (%) 6" GRAVEL SURFACING - SM-GM SILTY SAND AND GRAVEL 1 brown - 2 - 3 CL-ML SILTY LEAN CLAY/SANDY SILT - light brown 4 medium stiff - 5 CS 9 - 6 - 7 - 8 - 9 - 10 CS 15 - 11 CL SANDY LEAN CLAY - tan to light reddish brown 12 medium stiff to stiff - 13 - 14 - 15 CS 7 - 16 - 17 - 18 - 19 CL-CH SANDY LEAN TO FAT CLAY - light reddish brown 20 CS 22 very stiff - 21 - 22 - SP-GP SAND AND GRAVEL 23 reddish brown - medium dense 24 - 25 CS 39 0.0006 0.0004 UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Clean Gravels Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF Fines classify as ML or MH GM Silty gravelF,G, H Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H Clean Sands Cu ! 6 and 1 " Cc " 3E SW Well graded sandI Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI Fines classify as ML or MH SM Silty sandG,H,I Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines More than 12% finesD Fines classify as CL or CH SC Clayey sandG,H,I Silts and Clays PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Liquid limit less than 50 Inorganic PI < 4 or plots below “A” lineJ ML SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,N Fine-Grained Soils 50% or more passes the No. 200 sieve Organic Liquid limit - not dried < 0.75 OL Organic siltK,L,M,O Inorganic PI plots on or above “A” line CH Fat clayK,L,M Silts and Clays Liquid limit 50 or more PI plots below “A” line MH Elastic siltK,L,M Organic Liquid limit - oven dried Organic clayK,L,M,P Liquid limit - not dried < 0.75 OH Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well graded gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well graded sand with silt, SW-SC well graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D60/D10 Cc = GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1⅜" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube – 2.5" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger CS: California Barrel - 1.92" I.D., 2.5" O.D., unless otherwise noted RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”. For 2.5” O.D. California Barrel samplers (CB) the penetration value is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer falling 30 inches, reported as “blows per inch,” and is not considered equivalent to the “Standard Penetration” or “N-value”. WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. FINE-GRAINED SOILS COARSE-GRAINED SOILS BEDROCK (CB) Blows/Ft. (SS) Blows/Ft. Consistency (CB) Blows/Ft. (SS) Blows/Ft. Relative Density (CB) Blows/Ft. (SS) Blows/Ft. Consistency < 3 0-2 Very Soft 0-5 < 3 Very Loose < 24 < 20 Weathered 3-5 3-4 Soft 6-14 4-9 Loose 24-35 20-29 Firm 6-10 5-8 Medium Stiff 15-46 10-29 Medium Dense 36-60 30-49 Medium Hard 11-18 9-15 Stiff 47-79 30-50 Dense 61-96 50-79 Hard 19-36 16-30 Very Stiff > 79 > 50 Very Dense > 96 > 79 Very Hard > 36 > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Terms of Other Constituents Percent of Dry Weight Major Component of Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) Soilogic, Inc. 3050 67th Avenue, Suite 200  Greeley, CO 80634  (970) 535-6144 P.O. Box 1121  Hayden, CO 81639  (970) 276-2087 March 28, 2017 Quality Engineering, LLC 2637 Midpoint Drive, Suite E Fort Collins, Colorado 80234 Attn: Ms. Lisa Denke, P.E. Re: Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic Project # 17-1053 Ms. Denke: Soilogic, Inc. (Soilogic) personnel have completed the geotechnical subsurface exploration and pavement section design you requested for the alleyway paving to be completed as part of the off-site improvements associated with 317-321 Sherwood Street in Fort Collins, Colorado. The results of our subsurface exploration and pertinent geotechnical engineering recommendations are included with this report. A structural pavement section designs are also included. The purpose of our exploration was to describe the subsurface conditions encountered in the completed site borings and develop the test data necessary to provide recommendations concerning development of the alleyway subgrade soils and a pavement section design options for the alleyway. The conclusions and recommendations outlined in this report are based on results of the completed field and laboratory testing and our experience with subsurface conditions in this area. This project involves the paving of the alleyway located behind 317-321 Sherwood Street extending from West Magnolia Street north approximately 200 feet. At the time of our site exploration, the alleyway was in service and we expect the sewer utility had been in- place for an extended period. The alleyway was at approximate finish subgrade elevation at the time of drilling. Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 2 FIELD EXPLORATION To develop subsurface information for use in the pavement design, two (2) soil borings were advanced within the alleyway alignment to a depth of approximately ten (10) feet below alleyway subgrade level in accordance with the Larimer County Urban Area Street Standards (LCUASS). The boring locations were established in the field by Soilogic personnel by pacing and estimating angles and distances from identifiable site references. The boring locations should be considered accurate only to the degree implied by the methods used to make the field measurements. A diagram indicating the approximate boring locations is included with this report. Graphic logs of the auger borings are also included. The test holes were advanced using 4-inch diameter continuous-flight auger powered by a truck-mounted CME-45 drill rig. Samples of the subsurface materials were obtained at regular intervals using California barrel sampling procedures in general accordance with ASTM specification D-1586. As part of the D-1586 sampling procedure, standard sampling barrels are driven into the substrata using a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the samplers a distance of 12 inches is recorded and helpful in estimating the consistency or relative density of the soils encountered. In the California barrel sampling procedure, lesser disturbed samples are obtained in removable brass liners. Samples of the subsurface materials obtained in the field were sealed and returned to the laboratory for further evaluation, classification and testing. LABORATORY TESTING The samples collected were tested in the laboratory to measure natural moisture content and visually and/or manually classified in accordance with the Unified Soil Classification System (USCS). The USCS group symbols are indicated on the attached boring logs. An outline of the USCS classification system is included with this report. As part of the laboratory testing, a calibrated hand penetrometer (CHP) was used to estimate the unconfined compressive strength of essentially cohesive specimens. The CHP also provides a more reliable estimate of soil consistency than tactual observation Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 3 alone. Dry density, Atterberg limits, -200 wash and swell/consolidation tests were completed on selected samples to help establish specific soil characteristics. Atterberg limits tests are used to determine soil plasticity. The percent passing the #200 size sieve (-200 wash test) is used to determine the percentage of fine grained materials (clay and silt) in a sample. Swell/consolidation tests are performed to evaluate soil volume change potential with variation in moisture content. Swell/consolidation tests completed on samples obtained at a depth of approximately 2 feet below ground surface were inundated with water at a 150 psf confining pressure. As part of the completed laboratory testing, one (1) resistance value (R-value) test was completed on a representative subgrade sample for use in pavement design. The results of the completed laboratory tests are outlined on the attached boring logs and swell/consolidation summary sheets. SUBSURFACE CONDITIONS The subsurface materials encountered in the completed site borings can be summarized as follows. Approximately 6 inches of recycled asphalt pavement (RAP) was encountered at the surface at the boring locations. At the location of boring B-2, the RAP was underlain by apparent fill/utility backfill consisting of brown clayey sand and gravel. The RAP encountered at the location of boring B-3 and apparent fill encountered at the location of boring B-2 was underlain by light reddish brown to brown silty lean clay. The silty lean clay varied from soft to stiff in terms of consistency, exhibited low swell potential at in-situ moisture and density conditions and extended to depths ranging from approximately 7 to 8 feet below ground surface where it transitioned to tan to light reddish brown sandy lean to fat clay. The lean to fat clay was stiff in consistency and extended to the bottom of both borings at a depth of approximately 10 feet below present site grades. The stratigraphy indicated on the included boring logs represents the approximate location of changes in soil types. Actual changes may be more gradual than those indicated. Groundwater was not encountered in either of the completed site borings at the time of drilling. Groundwater levels will vary seasonally and over time based on weather conditions, site development, irrigation practices and other hydrologic conditions. Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 4 Perched and/or trapped groundwater conditions may also be encountered at times throughout the year. Perched water is commonly encountered in soils overlying less permeable soil layers and/or bedrock. Trapped water is typically encountered within more permeable zones of layered soil and bedrock systems. The location and amount of perched and/or trapped water can also vary over time. ANALYSIS AND RECOMMENDATIONS Roadway Subgrade Development The lean clay subgrade soils encountered in the completed site borings exhibited low swell potential at in-situ moisture and density conditions. The clayey sand and gravel encountered near surface at boring location B-2 would be expected to be non-expansive or possess low swell potential based on the materials physical properties and engineering characteristics. Based on results of the completed field and laboratory testing, it is our opinion the clayey sand and gravel and silty lean clay could be used for direct support of the alleyway pavements. Immediately prior to paving, we recommend the exposed subgrade soils be scarified to a depth of 9 inches, adjusted in moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. The moisture content of the scarified subgrade soils should be adjusted to be within the range of ±2% of standard Proctor optimum moisture content at the time of compaction. If fly ash stabilization of the pavement subgrade soils will be completed, reconditioning of the subgrade soils prior to fly ash treatment would not be required. Care should be taken to avoid disturbing the developed subgrade soils prior to paving. In addition, efforts to maintain the proper moisture content in the subgrade soils should be made. If subgrade soils are disturbed by the construction activities or allowed to dry out or become elevated in moisture content, those materials should be reworked in place or removed and replaced prior to surfacing. Proof-rolling of the alleyway subgrade soils should be completed prior to paving to help identify any areas of soft/unstable soils. Those areas identified as unstable would need to be mended prior to paving. Isolated areas of instability can be mended on a case by case basis. If more extensive areas of subgrade instability are encountered and depending on Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 5 the time of year when construction occurs and other hydrologic conditions, stabilization of the subgrade soils may become necessary to develop a suitable paving platform. Based on the materials encountered in the completed site borings and results of laboratory testing, it is our opinion fly ash stabilization of the pavement subgrades could be completed to develop a suitable paving platform. With the increase in support strength developed by the stabilization procedures, it is our opinion the zone of stabilized subgrade could be included in the pavement section design, slightly reducing the required thickness of overlying aggregate base course. Pavement section design options incorporating some structural credit for the fly ash stabilized subgrade soils are outlined below in Table I. Fly ash stabilization can eliminate some of the uncertainty associated with attempting to pave during periods of inclement weather. For half credit and if fly ash stabilization will be completed, we recommend the addition of 12% class ‘C’ fly ash based on component dry unit weights. A 12-inch thick stabilized zone should be constructed by thoroughly blending the fly ash with the in-place subgrade soils. Some “fluffing” of the finish subgrade level should be expected with the stabilization procedures. The blended materials should be adjusted to within ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the material’s standard Proctor maximum dry density within two (2) hours of fly ash addition. Pavement Design Site pavement could be supported directly on stable reconditioned subgrade soils or fly ash treated subgrade soils developed as outlined above. The pavement subgrade soils are expected to consist of reconditioned silty lean clay and clayey sand and gravel. The silty lean clay soils classify as A-6 soils in accordance with The American Association of State Highway and Transportation Officials (AASHTO) classification system and would be expected to exhibit low remolded shear strength. An R-value of less than 5 was determined on a representative subgrade sample obtained from the borings and used in pavement section design. Design ESAL’s were provided by City of Fort Collins personnel. Serviceability loss and reliability were obtained from the current LCUASS. Outlined below in Table I. are pavement section design options for the project alleyway. Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 6 TABLE 1 – PAVEMENT SECTION DESIGN Roadway Classification ESAL’s Reliability % Loss Resilient Modulus (Mr) Design Structural Number Option A – Composite Surface Asphalt (Grading S or SX) Aggregate Base (Class 5 or 6) (Structural Number) Option B – Composite on Fly Ash Asphalt (Grading S or SX) Aggregate Base (Class 5 or 6) Fly Ash Treated Subgrade (Structural Number) 317-321 Sherwood Street Alleyway Alley/Local Residential 73,000 80% 2.5% 3025 (2.83) 5” (0.44/inch) 6” (0.11/inch) (2.86) 4” (0.44/inch) 5” (0.11/inch) 12” (10 @ .05/inch) (2.81) Asphaltic concrete should consist of a bituminous plant mix composed of a mixture of aggregate, filler, binders and additives if required meeting the design requirements of the City of Fort Collins (LCUASS). Aggregate used in the asphaltic concrete for local residential roadways should meet specific gradation requirements for Colorado Department of Transportation (CDOT) grading S (3/4 inch minus) or SX (1/2 inch minus) mixes. Hot mix asphalt designed using “Superpave” criteria should be compacted to within 92 to 96% of the materials Maximum Theoretical Density. Aggregate base should be consistent with CDOT requirements for Class 5 or 6 aggregate base, placed in loose lifts not to exceed 9 inches thick and compacted to at least 95% of the materials standard Proctor maximum dry density. The proposed pavement section design does not include an allowance for excessive loading conditions imposed by heavy construction vehicles or equipment. The recommended pavement sections are minimums and periodic maintenance efforts should be expected. A preventative maintenance program can help increase the service life of the roadway pavement. Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 7 Drainage Positive drainage is imperative for long term performance of the alleyway pavements. Water which is allowed to pond adjacent to alleyway pavements can result in a loss of subgrade support and premature failure of the overlying pavement section. LIMITATIONS This report was prepared based upon the data obtained from the completed site exploration, laboratory testing, engineering analysis and any other information discussed. The completed borings provide an indication of subsurface conditions at the boring locations only. Variations in subsurface conditions can occur in relatively short distances away from the borings. This report does not reflect any variations which may occur across the site or away from the borings. If variations in the subsurface conditions anticipated become evident, the geotechnical engineer should be notified immediately so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any biological or environmental assessment of the site or identification or prevention of pollutants or hazardous materials or conditions. Other studies should be completed if concerns over the potential of such contamination or pollution exist. The geotechnical engineer should be retained to review the plans and specifications so that comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. The geotechnical engineer should also be retained to provide testing and observation services during construction to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with the generally accepted standard of care for the profession. No warranties express or implied, are made. The conclusions and recommendations contained in this report should not be considered valid in the event that any changes in the nature, design or location of the project as outlined in Geotechnical Subsurface Exploration and Pavement Design Report 317-321 Sherwood Street Alleyway Pavements Fort Collins, Colorado Soilogic # 17-1053 8 this report are planned, unless those changes are reviewed and the conclusions of this report modified and verified in writing by the geotechnical engineer. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information or if we can be of further assistance to you in any way, please do not hesitate to contact us. Very Truly Yours, Soilogic, Inc. Reviewed by: Wolf von Carlowitz, P.E. Darrel DiCarlo, P.E. Principal Engineer Senior Project Engineer 36746 44271 LOG OF BORING B-2 1/1 CME 45 4" CFA Automatic CP/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 6" RECYCLED ASPHALT PAVEMENT - SC-GC FILL - CLAYEY SAND AND GRAVEL 1 brown - 2 - 3 CS 11 18.9 108.2 9000+ 0.4% - - - - CL SILTY LEAN CLAY - light reddish brown 4 soft to stiff - 5 CS 5 19.6 96.3 6000 - - 34 15 80.3% - 6 - 7 - 8 CL-CH SANDY LEAN TO FAT CLAY - tan to light reddish brown 9 stiff - 10 CS 14 19.7 107.3 7000 - - - - - BOTTOM OF BORING 10' - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 Sheet Drilling Rig: Water Depth Information 317-321 SHERWOOD STREET ALLEYWAY PAVEMENTS LOG OF BORING B-3 1/1 CME 45 4" CFA Automatic CP/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 6" RECYCLED ASPHALT PAVEMENT - 1 - CL SILTY LEAN CLAY 2 brown - medium stiff 3 CS 8 17.6 110.8 9000+ 0.6% - - - - - 4 - 5 CS 7 18.5 100.3 9000+ - - - - - - 6 - 7 - CL-CH SANDY LEAN TO FAT CLAY 8 reddish brown - stiff 9 - 10 CS 16 18.6 111.3 9000+ - - - - - BOTTOM OF BORING 10' - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 Sheet Drilling Rig: Water Depth Information 317-321 SHERWOOD STREET ALLEYWAY PAVEMENTS Liquid Limit - Plasticity Index - % Passing #200 - Dry Density (pcf) 108.2 317-321 SHERWOOD STREET ALLEYWAY PAVEMENTS FORT COLLINS, COLORADO Project # 17-1053 March 2017 SWELL/CONSOLIDATION TEST SUMMARY Sample ID: B-2 @ 2 Sample Description: (Swell Only) Initial Moisture 18.9% Final Moisture 19.5% % Swell @ 500 psf 0.4% Swell Pressure (psf) - -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density (pcf) 110.8 SWELL/CONSOLIDATION TEST SUMMARY 317-321 SHERWOOD STREET ALLEYWAY PAVEMENTS FORT COLLINS, COLORADO Project # 17-1053 March 2017 Initial Moisture 17.6% Sample ID: B-3 @ 2 Sample Description: (Swell Only) Final Moisture 19.1% % Swell @ 500 psf 0.6% Swell Pressure (psf) - -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Clean Gravels Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF Fines classify as ML or MH GM Silty gravelF,G, H Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H Clean Sands Cu ! 6 and 1 " Cc " 3E SW Well graded sandI Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI Fines classify as ML or MH SM Silty sandG,H,I Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines More than 12% finesD Fines classify as CL or CH SC Clayey sandG,H,I Silts and Clays PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Liquid limit less than 50 Inorganic PI < 4 or plots below “A” lineJ ML SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,N Fine-Grained Soils 50% or more passes the No. 200 sieve Organic Liquid limit - not dried < 0.75 OL Organic siltK,L,M,O Inorganic PI plots on or above “A” line CH Fat clayK,L,M Silts and Clays Liquid limit 50 or more PI plots below “A” line MH Elastic siltK,L,M Organic Liquid limit - oven dried Organic clayK,L,M,P Liquid limit - not dried < 0.75 OH Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well graded gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well graded sand with silt, SW-SC well graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D60/D10 Cc = GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1⅜" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube – 2.5" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger CS: California Barrel - 1.92" I.D., 2.5" O.D., unless otherwise noted RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”. For 2.5” O.D. California Barrel samplers (CB) the penetration value is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer falling 30 inches, reported as “blows per inch,” and is not considered equivalent to the “Standard Penetration” or “N-value”. WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. FINE-GRAINED SOILS COARSE-GRAINED SOILS BEDROCK (CB) Blows/Ft. (SS) Blows/Ft. Consistency (CB) Blows/Ft. (SS) Blows/Ft. Relative Density (CB) Blows/Ft. (SS) Blows/Ft. Consistency < 3 0-2 Very Soft 0-5 < 3 Very Loose < 24 < 20 Weathered 3-5 3-4 Soft 6-14 4-9 Loose 24-35 20-29 Firm 6-10 5-8 Medium Stiff 15-46 10-29 Medium Dense 36-60 30-49 Medium Hard 11-18 9-15 Stiff 47-79 30-50 Dense 61-96 50-79 Hard 19-36 16-30 Very Stiff > 79 > 50 Very Dense > 96 > 79 Very Hard > 36 > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Terms of Other Constituents Percent of Dry Weight Major Component of Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/13/2016 Page 1 of 3 4492470 4492480 4492490 4492500 4492510 4492520 4492530 4492540 4492550 4492560 4492570 4492470 4492480 4492490 4492500 4492510 4492520 4492530 4492540 4492550 4492560 4492570 492750 492760 492770 492780 492790 492800 492810 492820 492830 492840 492850 492860 492870 492880 492890 492900 492750 492760 492770 492780 492790 492800 492810 492820 492830 492840 492850 492860 492870 492880 492890 492900 40° 35' 2'' N 105° 5' 8'' W 40° 35' 2'' N 105° 5' 1'' W 40° 34' 58'' N 105° 5' 8'' W 40° 34' 58'' N 105° 5' 1'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 35 70 140 210 Feet 0 10 20 40 60 Meters Map Scale: 1:720 if printed on A landscape (11" x 8.5") sheet. Warning: Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features 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: http://websoilsurvey.nrcs.usda.gov 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 Map Unit Legend Larimer County Area, Colorado (CO644) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 35 Fort Collins loam, 0 to 3 percent slopes 0.5 100.0% Totals for Area of Interest 0.5 100.0% Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/13/2016 Page 3 of 3 DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF Table RO-3—Recommended Percentage Imperviousness Values Land Use or Surface Characteristics Percentage Imperviousness Business: Commercial areas 95 Neighborhood areas 85 Residential: Single-family * Multi-unit (detached) 60 Multi-unit (attached) 75 Half-acre lot or larger * Apartments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools 50 Railroad yard areas 15 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off-site flow analysis (when land use not defined) 45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 0 Lawns, clayey soil 0 * See Figures RO-3 through RO-5 for percentage imperviousness. C K 1 . 31 i 3 1 . 44 i 2 1 . 135 i 0 . 12 A A for CA 0, otherwise CA = 0 (RO-6) C K 0 . 858 i 3 0 . 786 i 2 0 . 774 i 0 . 04 CD CD (RO-7) C 2 B A CD C C 2007-01 RO-9 Urban Drainage and Flood Control District Composite C Values FAITH FAMILY Asphalt Area (acres) Concrete Area (acres) Gravel (acres) Roofs (acres) Lawns (acres) Total Area Minor (2-YR) Major (100-YR) (C = 0.95) (C = 0.95) (C = 0.50) (C = 0.95) (C = 0.15) (acres) Composite "C" Composite "C" (Cf x C) E1 E1 0.000 0.000 0.055 0.009 0.010 0.074 0.51 0.63 E2 E2 0.000 0.051 0.000 0.143 0.168 0.362 0.58 0.72 ALLEY ALLEY 0.000 0.000 0.058 0.000 0.036 0.094 0.37 0.46 D1 B1 0.016 0.012 0.019 0.000 0.027 0.074 0.54 0.68 D2 B2 0.000 0.051 0.000 0.143 0.168 0.362 0.58 0.72 ALLEY ALLEY 0.072 0.017 0.000 0.000 0.005 0.094 0.91 1.00 Notes: Composite C values obtained from Table R0-11 Major Storm Runoff factored per Table R0-12 Developed Design Point Basin(s) Existing MAP Faith Family Rational Method.xlsx 2/27/2017 Imperviousness FAITH FAMILY Asphalt Area (acres) Concrete Area (acres) Gravel (acres) Roofs (acres) Lawns (acres) Total Area Percent (I = 100) (I = 100) (I = 40) (I = 90) (I = 0) (acres) Imperviousness E1 E1 0.000 0.000 0.055 0.009 0.010 0.0740 41% E2 E2 0.000 0.051 0.000 0.143 0.168 0.3620 50% ALLEY ALLEY 0.000 0.000 0.058 0.000 0.036 0.0940 25% D1 B1 0.016 0.012 0.019 0.000 0.027 0.074 48% D2 B2 0.000 0.051 0.000 0.143 0.168 0.362 50% ALLEY ALLEY 0.072 0.017 0.000 0.000 0.005 0.094 95% Notes: Percent Impervious Values per Table R0-3, Urban Drainage Manual Developed Design Point Basin (s) Existing CAG Faith Family Rational Method.xlsx 2/27/2017 Basin Flow Calculations FAITH FAMILY Area Minor Major (acres) Composite "C" Composite "C" Length (ft) Slope (%) Minor tov (min) a Major tov (min) a Length (ft) Slope (%) Channel Type Velocity (fps) c t t (min) Minor TC (min) Major TC (min) 2-yr 10-yr 100-yr 2-yr 10-yr 100-yr E1 E1 0.0740 0.51 0.63 17 0.84 4.84 3.81 0 0.40 PA 1.26 0.00 5.00 5.00 2.85 4.87 9.95 0.11 0.18 0.47 E2 E2 0.3620 0.58 0.72 110 1.20 9.62 6.95 86 0.75 PA 1.73 0.83 10.45 7.78 2.17 3.71 8.38 0.45 0.78 2.19 ALLEY ALLEY 0.0940 0.37 0.46 15 1.20 5.00 4.38 200 0.40 PA 1.26 2.64 7.64 7.01 2.46 4.21 8.80 0.08 0.14 0.38 D1 B1 0.0740 0.54 0.68 40 2.00 5.23 3.96 0 0.50 PA 1.41 0.0000 5.23 5.00 2.85 4.87 9.95 0.11 0.20 0.50 D2 B2 0.3620 0.58 0.72 110 1.20 9.62 6.95 86 0.75 PA 1.73 0.8275 10.45 7.78 2.17 3.71 8.38 0.45 0.78 2.19 ALLEY ALLEY 0.0940 0.91 1.00 15 1.50 1.22 0.63 200 0.50 PA 1.41 2.3570 5.00 5.00 2.85 4.87 9.95 0.24 0.42 0.94 Notes: a b HM = Heavy Meadow, TF = Tillage/field, PL = Short pasture and lawns, BG = Nearly bare ground, GW = Grassed Waterway, PA = Paved Areas c Velocity alues from Figure 3-3/Table RO-2 Estimate of Average Flow Velocity for use with the Rational Method Design Point Developed Existing Initial/Overland Time Final TC Intensity (in/hr) Basin Flows (cfs) Basin (s) Travel Time 1 / 3 1 . 87 ( 1 . 1 ) 1 / 2 S CC D t f ov   CAG Faith Family Rational Method.xlsx 2/27/2017 APPENDIX B: Hydraulic Computations Fort Collins Modified FFA Method Infiltration Calculation Project: Basin ID: Design Information (Input): Design Information (Input): Catchment Drainage Imperviousness Ia = 48.00 percent Catchment Drainage Imperviousness I a = 48.00 percent Catchment Drainage Area A = 0.074 acres Catchment Drainage Area A = 0.074 acres Predevelopment NRCS Soil Group Type = C A, B, C, or D Predevelopment NRCS Soil Group Type = C A, B, C, or D Return Period for Detention Control T = 2 years (2, 5, 10, 25, 50, or 100) Return Period for Detention Control T = 100 years (2, 5, 10, 25, 50, or 100) Time of Concentration of Watershed Tc = 5 minutes Time of Concentration of Watershed Tc = 5 minutes Allowable Unit Release Rate q = 0.01 cfs/acre Allowable Unit Release Rate q = 0.01 cfs/acre Determination of Average Outflow from the Basin (Calculated): Determination of Average Outflow from the Basin (Calculated): Runoff Coefficient C = 0.54 Runoff Coefficient C = 0.68 Inflow Peak Runoff Qp-in = 0.11 cfs Inflow Peak Runoff Qp-in = 0.50 cfs Allowable Peak Outflow Rate Qp-out = 0.01 cfs Allowable Peak Outflow Rate Qp-out = 0.01 cfs Mod. FAA Minor Storage Volume = 98 cubic ft Mod. FAA Major Storage Volume = 165 cubic ft 5 <- Enter Rainfall Duration Incremental Increase Value Here (e.g. 5 for 5-Minutes) Rainfall Rainfall Inflow Adjustment Average Outflow Storage Rainfall Rainfall Inflow Adjustment Average Outflow Storage Duration Intensity Volume Factor Outflow Volume Volume Duration Intensity Volume Factor Outflow Volume Volume minutes inches / hr cubic feet "m" cfs cubic feet cubic feet minutes inches / hr cubic feet "m" cfs cubic feet cubic feet (input) (output) (output) (output) (output) (output) (output) (input) (output) (output) (output) (output) (output) (output) 0 0.00 0.000 0.00 0.00 0.000 0.000 0 0.00 0.000 0.00 0.00 0.000 0.000 5 2.85 34.166 1.00 0.01 3.000 31.166 5 9.95 55.223 1.00 0.01 3.900 51.323 10 2.21 52.987 0.75 0.01 4.500 48.487 10 7.72 85.692 0.75 0.01 5.850 79.842 15 1.87 67.253 0.67 0.01 6.000 61.253 15 6.52 108.558 0.67 0.01 7.800 100.758 20 1.61 77.203 0.63 0.01 7.500 69.703 20 5.60 124.320 0.63 0.01 9.750 114.570 25 1.43 85.714 0.60 0.01 9.000 76.714 25 4.98 138.195 0.60 0.01 11.700 126.495 30 1.30 93.506 0.58 0.01 10.500 83.006 30 4.52 150.516 0.58 0.01 13.650 136.866 35 1.17 98.182 0.57 0.01 12.000 86.182 35 4.08 158.508 0.57 0.01 15.600 142.908 40 1.07 102.617 0.56 0.01 13.500 89.117 40 3.74 166.056 0.56 0.01 17.550 148.506 45 0.99 106.813 0.56 0.01 15.000 91.813 45 3.46 172.827 0.56 0.01 19.500 153.327 50 0.92 110.290 0.55 0.01 16.500 93.790 50 3.23 179.265 0.55 0.01 21.450 157.815 55 0.87 114.725 0.55 0.01 18.000 96.725 55 3.03 184.982 0.55 0.01 23.400 161.582 60 0.82 117.962 0.54 0.01 19.500 98.462 60 2.86 190.476 0.54 0.01 25.350 165.126 Determination of MINOR Detention Volume Using Modified FAA Method Determination of MAJOR Detention Volume Using Modified FAA Method DETENTION VOLUME BY THE MODIFIED FAA METHOD Faith Family (For catchments less than 160 acres only. For larger catchments, use hydrograph routing method) (NOTE: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended) Project No: 7040-007 Project Name: Faith Family Designer: RJP Date: 4/18/2017 Basin: B2 0.85 in/hr or 1.96759E-05 ft/sec * Infiltation Rate taken from soils report 961 sq. ft. 0.019 cfs Safty Factor 1.5 0.013 cfs 165 cubic ft 13089 seconds or 3.6 hrs 100-YR Event Volume Time to Drain Final Allowable Infiltrating Flow Infiltration Rate f= Surface Area Allowable Infiltrating Flow Infiltration Calculator Quality Engineering 2637 Midpoint Drive, Suite E Fort Collins, CO 80525 (970) 416-7891 APPENDIX C: Map Pocket Drainage Plan X X X X X X UT UT UT UT UT UT UT UT UT UT WS WS WS WS WS WS WS S W O F.F.=5001.0 F.F.=5002.9 F.F.=5003.8 F.F.=5003.4 F.F.=5003.3 F.F.=5003.4 F.F.=5003.4 F.F.=5002.4 EXISTING WOOD DECK EXISTING WOOD PORCH EXISTING 0.5' WIDE BRICK WALL EXISTING 10" DIAMETER COLUMN (TYP) EXISTING 0.5' WIDE CONCRETE WALL EXISTING DRAIN CHASE DRAIN CHASE EXISTING WOOD STAIRS STONE STAIRS EXISTING CONCRETE RAMP -EXISTING SIDEWALK- -EXISTING SIDEWALK- -EXISTING SIDEWALK- -EXISTING SIDEWALK- -EXISTING 5' SW- EXISTING CONCRETE PAN -GRASS- -GRASS- -GRASS- -GRASS- -GRASS- SS SS SS SS SS SS SS SS SS SS SS SS EXISTING SANITARY CLEANOUT CONCRETE COURTYARD EXISTING CONCRETE STAIRS 2 STORY RESIDENTIAL FRAME NO BASEMENT 2 STORY RESIDENTIAL FRAME & BRICK WITH BASEMENT SOUTH SHERWOOD STREET 321 SOUTH SHERWOOD STREET PARCEL 1 9,500 SQ.FT. 0.218 ACRES 317 SOUTH SHERWOOD STREET PARCEL 2 9,500 SQ.FT. 0.218 ACRES EXISTING WOOD SHED F.F.=5002.3 F.F.=5002.4 EXISTING WATER VALVE BLOCK 73 ALLEY EXISTING GATE X X X X X X X X X X X X X (UP) (UP) (UP) (UP) X X X X X X X X X X X X X X X X X X X X W W W W W W W W W W W W W WS WS WS WS WS WS WS EXISTING 3/4" COPPER SERVICE EXISTING 2" COPPER FIRE SERVICE EXISTING 3/4" COPPER SERVICE 6" SANITARY SEWER 8" SANITARY SEWER SIGN "2 HOUR PARKING" 4" CAST IRON WATER LINE 325 SHERWOOD STREET 512 WEST MAGNOLIA STREET EXISTING 5' SW X X X X EXISTING ELECTRIC BOXES EXISTING ELECTRIC BOXES EXISTING DRAIN CHASE EXISTING VERTICAL CURB & GUTTER (TYP) -EXISTING ACCESS- FS FS FS FS FS WS WS WS WS WS WS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS EXISTING 4" PVC SANITARY SERVICE SMH #1 RIM=5002.2 8" RCP (S) INV=4996.6 8" RCP (N) INV=4996.5 -EXISTING ACCESS- PROPOSED OUTFLOW CURB 2.29 2.29 (2.11) (1.85) 2.57 2.29 (1.23) (1.60) (1.32) (1.27) (0.68) 0.91 2.69 2.41 2.42 1.13 2.19 BLOCK 73 ALLEY 8" SANITARY SEWER 6" SANITARY SEWER 2.14 2.16 2.39 2.54 2.66 1.99 2.29 2.05 1.91 1.44 1.44 1.85 1.99 1.85 1.84 0.97 0.98 1.41 (0.12) (1.81) DRAIN CHASE (1.88) (1.00) (1.66) (2.06) (2.17) (1.86) 1.67 5001 5001 5002 5002 5002 5002 5002 5003 5003 5002 5002 5002 5001 5001 5001 5000 5001 5003 5002 5001 5002 5002 5001 5001 5001 EXISTING WATER VALVE EXISTING VERTICAL CURB & GUTTER (TYP) EXISTING 5' SW EXISTING 3/4" COPPER SERVICE -EXISTING SIDEWALK- -EXISTING ACCESS- SMH #1 RIM=5002.2 8" RCP (S) INV=4996.6 8" RCP (N) INV=4996.5 -EXISTING ACCESS- CITY FLOOD FRINGE: HIGH RISK CITY FLOODWAY: HIGH RISK 325 SHERWOOD STREET EXISTING 0.5' WIDE CONCRETE WALL EXISTING CONCRETE RAMP PROPOSED ROLL-OVER CURB DRAINAGE AND EROSION CONTROL PLAN 10' C4.0 SCALE: 1" = 10' 0 20' DRAINAGE LEGEND D1 FAITH FAMILY HOSPITALITY 317-321 SHERWOOD STREET FORT COLLINS, CO 80521 FOR BURIED UTILITY INFORMATION THREE (3) BUSINESS DAYS BEFORE YOU DIG CALL 811 (OR 1-800-922-1987) UTILITY NOTIFICATION CENTER OF COLORADO (UNCC) WWW.UNCC.ORG R L.I.D. LEGEND BASIN ID MINOR "C" COEFFICIENT MAJOR "C" COEFFICIENT DRAINAGE AREA EROSION CONTROL LEGEND D2 D1 FLOODPLAIN NOTES SYMBOL LEGEND G G (UP) (UT) SS X WS WS WS WS SS R/W WS WS W R/W (OHP) EP 10.00 2.05% W FS E NOTE: ALL EXISTING TREES TO BE PROTECTED IN PLACE ENGINEERING & SURVEYING 4045 St. Cloud Drive, Suite 180 Loveland, CO 80538 [P] 970-622-2095 [F] 307-742-7403 the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 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. Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/13/2016 Page 2 of 3 With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Terms of Other Constituents Percent of Dry Weight Term Plasticity Index Trace With Modifiers < 5 5 – 12 > 12 Non-plastic Low Medium High 0 1-10 11-30 30+ F If soil contains ! 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains ! 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ! 30% plus No. 200 predominantly sand, add “sandy” to group name. M If soil contains ! 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI ! 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. FORT COLLINS, COLORADO Project # 17-1053 March 2017 USCS Sampler Atterberg Limits Start Date 3/6/2017 Auger Type: During Drilling None Finish Date 3/6/2017 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 24 Hours After Drilling - FORT COLLINS, COLORADO Project # 17-1053 March 2017 USCS Sampler Atterberg Limits Start Date 3/6/2017 Auger Type: During Drilling None Finish Date 3/6/2017 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 24 Hours After Drilling - With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Terms of Other Constituents Percent of Dry Weight Term Plasticity Index Trace With Modifiers < 5 5 – 12 > 12 Non-plastic Low Medium High 0 1-10 11-30 30+ F If soil contains ! 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains ! 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ! 30% plus No. 200 predominantly sand, add “sandy” to group name. M If soil contains ! 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI ! 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. 0.0004 0.0002 0.008 USCS Sampler Atterberg Limits Surface Elev. - Field Personnel: 3 Days After Drilling 15.5' Estimated Permeability Rate (cm/s) Finish Date 3/6/2017 Hammer Type: After Drilling 15.5' Sheet Drilling Rig: Water Depth Information Start Date 3/6/2017 Auger Type: During Drilling 15.5' 317-321 SHERWOOD STREET DRY WELL FORT COLLINS, COLORADO Project # 17-1053 March 2017