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Home My WebLink AboutCNG SHOP EXPANSION - MA220136 - SUBMITTAL DOCUMENTS - ROUND 3 - DRAINAGE REPORT DRAINAGE REPORT FOR CNG SHOP EXPANSION AT 835 WOOD STREET FORT COLLINS, CO 80521 PREPARED FOR THE CITY OF FORT COLLINS Fort Collins, CO 80523 JANUARY 31, 2023 835 Wood Street Drainage Report Page 1 of 7 TABLE OF CONTENTS GENERAL LOCATION AND EXISTING SITE INFORMATION ......................................................... 3 DRAINAGE BASINS AND HISTORIC RUNOFF .......................................................................... 3 HISTORIC DRAINAGE ..................................................................................................... 4 PROPOSED DRAINAGE .................................................................................................. 4 DRAINAGE DESIGN CRITERIA ............................................................................................ 5 HYDROLOGIC METHOD AND DESIGN STORM FREQUENCIES ................................................. 5 HYDRAULIC CRITERIA .................................................................................................... 5 VARIANCES FROM THE CRITERIA......................................................................................... 5 FOUR STEP PROCESS ........................................................................................................ 5 DRAINAGE FACILITY DESIGN ............................................................................................. 6 GENERAL CONCEPT ..................................................................................................... 6 STORMWATER POLLUTION PREVENTION/EROSION CONTROL .................................................. 6 TEMPORARY EROSION CONTROL .................................................................................... 6 PERMANENT EROSION CONTROL .................................................................................... 6 CONCLUSIONS................................................................................................................ 7 REFERENCES ................................................................................................................... 7 Appendix A – Referenced Information 1. Vicinity Map 2. Geotechnical Report Summary Logs of Exploratory borings 3. FEMA FIRM Map 4. NRCS Websoil Survey 5. Figure 1: Historic percentage of Imperviousness 6. Figure 2: Proposed Percentage of Imperviousness Appendix B – Hydrologic/Hydraulic Computations 1. Rational Method Calculations 2. BMP Calculations 835 Wood Street Drainage Report Page 2 of 7 ENGINEER’S STATEMENT: “I hereby certify that this report (plan) for the Drainage Design for the City of Fort Collins CNG Shop Expansion was prepared by me (or under my direct supervision) in accordance with the provisions of the City of Fort Collins Standards for the Responsible Parties thereof. I understand that the City of Fort Collins does not and shall not assume liability for drainage facilities designed by others.” ______________________________ Erik T. Nakos Registered Professional Engineer State of Colorado No. 40776 835 Wood Street Drainage Report Page 3 of 7 GENERAL LOCATION AND EXISTING SITE INFORMATION The Fort Collins CNG (site) is located in Section 2, Township 7 North, Range 69 West of the 6th Principal Meridian, in Larimer County, Fort Collins, Colorado. Refer to Appendix A for the site vicinity map. The site is bordered to the south by W Vine Dr., to the east by Wood Street, and to the east by North Shields Street. The existing site is predominantly an asphalt parking lot, a service building, an existing detention pond, concrete walks, and landscaping. The site is approximately 6.4 acres of previously developed property and has a historical percent impervious of 49.6%. The historical drainage facilities are expected to hold the required volume necessary for the site. The existing ground surface is relatively flat, generally sloping to the north at grades ranging from 1.0% to 3.0%. From the geotechnical report dated April 24, 2020 the soil is mainly sandy gravel. Groundwater was encountered at 11 ft to 12 ft below the ground surface. The Summary Logs of Exploratory Borings from the geotechnical report is attached in Appendix A. The site is located outside FEMA and City of Fort Collins mapped 100-year and 500-year floodplains, per FEMA Flood Risk Map Number 08069C0976F, effective date 12/19/2006 and 08069C0977G, effective date 6/17/2008. The site is comprised of hydrologic soil group A and B per NRCS soil survey. The FEMA Firm Map and NRCS Websoil Survey are included in Appendix A. In general, the proposed redevelopment of the site consists of constructing an addition to the existing building, restriping and replacing potions of the existing asphalt parking area, the addition of some gravel parking area, and the construction of a rain garden. Increased imperviousness for the redevelopment will be routed to the proposed rain garden for treatment and storage to supplement the existing pond. The site development will increase the overall percent impervious slightly by 1.5% to a total of 51.1% from the historical 49.6%. A rain garden will treat the WQCV for the entire basin being affected by redevelopment. The volume treated for water quality is greater than the volume increase from change in imperviousness allowing the existing facilities to function historically. As of this time no historical drainage reports have been available for the existing facility. It is assumed that the existing facilities were designed to detain the existing conditions. DRAINAGE BASINS AND HISTORIC RUNOFF 835 Wood Street Drainage Report Page 4 of 7 HISTORIC DRAINAGE The existing site consists of two basins. The runoff from the existing site sheet flows to the north through concrete pans into the existing detention pond. Flows enter the storm system located in Wood Street via an existing outlet structure and storm infrastructure located at the south end of the existing pond. PROPOSED DRAINAGE Proposed drainage patterns are to remain generally the same as the current with the exception of the flows along the northern redeveloped portion of the site being routed to the proposed rain garden before discharging into the existing detention pond. The bioretention system will be utilized for low impact development (LID) treatment requirements of the site. The rain garden has been designed to treat the entire contributing basin plus the additional volume required to detain any excess runoff from the increase in imperviousness before flows enter the existing detention pond, this ensures that the 75% treatment requirement is exceeded. The bioretention systems will reduce runoff, treat and slowly release the water quality capture volume as part of the four step process for the City of Fort Collins criteria on BMP selection. The rain garden is designed to trat 1352 cubic feet of flows. This volume is the WQCV for the entire basin (1,176 cubic feet) and the excess 100-yr volume from the addition 1.5% imperviousness to the basin (135 cubic feet). Calculation sheets are located in the appendix. For the purposes of calculations, the site was divided into 2 basins. Basin P1 includes a portion of the proposed building addition, portions of repaving, and part of a new concrete drainage pan. Historically Basin P1 includes the existing drainage facilities for the site. Historical drainage patterns will be maintained for this basin and flows are considered to be equal to existing conditions. Basin P2 will include the proposed additional asphalt parking area, a portion of the proposed building addition, a majority of the repaved area, and a rain garden with its appurtenant flow conveyance facilities. Flows gathered for treatment in the rain garden will be discharged into the existing detention pond and follow historical drainage patterns. There are four downspouts draining into various drainage pans or trench drains. The downspouts along the southern portion of the proposed addition will drain into the rebuilt concrete pan and follow historical drainage patterns to the existing pond. An existing downspout along the northern portion of the existing building and a proposed downspout along the northern section of the proposed addition will be routed through trench drains into the rain garden to be pretreated before release into the existing pond. 835 Wood Street Drainage Report Page 5 of 7 DRAINAGE DESIGN CRITERIA HYDROLOGIC METHOD AND DESIGN STORM FREQUENCIES The drainage for the site was designed to meet or exceed the City of Fort Collins’s Standards and Specifications, including the Stormwater Criterial Manual which incorporates most of the Mile High Flood District’s (MFHD) Urban Storm Drainage Criteria Manual (USDCM). The design one hour point rainfall used for the 2 year and 100 year storm events are 0.82 inches and 2.86 inches respectively. The Rational Method (Q=CIA) was used to determine the storm runoff (Q) from the areas contributing to the new storm system, with composite runoff coefficients (C) and contributing areas (A) given for design points in sub-basins. The runoff coefficients for various land usages were obtained from FCDCM, Chapter 5. Intensities (I) were determined using the Time-Intensity- Frequency equations, and a calculated Time of Concentration (tc). Hydraulic Criteria. See Appendix B for the runoff coefficient calculations. HYDRAULIC CRITERIA The proposed drainage system has been designed to comply with the City of Fort Collins Stormwater Criteria Manual. The MHFD UD-BMP spreadsheet version 3.07 was used to analyze the designed bioretention. Area drains were sized using MHFD’s USDCM Section 3.3.6 and calculations are included with the rational calculations in Appendix B. Complete drainage plans, details, dimensions, etc. are included in the grading and drainage plans in the site’s construction documents. VARIANCES FROM THE CRITERIA No variances are requested for this design. FOUR STEP PROCESS The Four Step Process implemented by the City of Fort Collins for stormwater quality management is: 1. Reduce runoff through use of Low Impact Development (LID) and Minimizing Directly Connected Impervious Area (MDCIA) 2. Implement BMPs that provide a WQCV with slow release. 3. Stabilize Streams 4. Implement site specific and other source control BMPs. This project is addressing this Four Step Process in the following ways; 1. The reduction of impervious area compared to historical, as well as the use of LID bioretention planters to reduce runoff 835 Wood Street Drainage Report Page 6 of 7 2. The use of the LID biorentention system to capture and slow release in concert with the existing detention facility. 3. There is no negative impact to stream erosion with the development of this site as compared to historical. 4. Runoff from cleaning and maintenance procedures will be routed along a path allowing for sedimentation and separation before entering the drainage facilities. Location of these activities is located at the furthest point source possible. DRAINAGE FACILITY DESIGN GENERAL CONCEPT The site’s existing stormwater facilities and conveyance BMPs were designed to detain and treat the site as it exists today. The current design will provide pretreatment for the flows in 70% of the redevelopment area. Due to a relatively low increase in imperviousness (1.5%) the additional volume of storage within the rain garden (1378 cubic feet) will provide extra storage to ensure detention of flows higher than the WQCV. The proposed bioretention facility will treat storm runoff for a minimum of 50% of the modified or added impervious area on the site for water quality treatment prior to discharging into the existing detention area, satisfying the City of Fort Collins LID requirements. These features will facilitate sedimentation and filtration while limiting erosion, providing both treatment and slowed release of the water quality capture volume. The proposed redevelopment of this site will serve to limit water quality and quantity impacts to natural drainageways by decreasing the frequency, rate, duration, and volume of runoff. STORMWATER POLLUTION PREVENTION/EROSION CONTROL As site is less than 1 acre of disturbed area, an erosion control report is not required per City of Fort Collins Storm Criteria. However, an erosion control plan and escrow is submitted to meet with City requirements. During construction, temporary erosion and sediment control practices will be used to limit soil erosion and sediment discharge off the site and into public existing stormwater infrastructure. TEMPORARY EROSION CONTROL A temporary erosion control plan is to be implemented for the site during construction. Temporary erosion control measures include, but are not limited to, vehicle tracking control, concrete washout areas, and inlet and slope protection provided using erosion control wattles/sediment control logs, rock socks, etc. All temporary erosion control measures are to be removed after they are deemed unnecessary. A general erosion control plan has been provided in the civil construction documents. PERMANENT EROSION CONTROL Chapter 2 of the Urban Drainage and Flood Control District’s Urban Storm Drainage Criteria Manual Volume 3 (USDCM) provides guidelines for the selection of appropriate permanent structural BMPs for a site that is to be developed or redeveloped. The 835 Wood Street is best characterized as a “conventional redevelopment” with under 1 acre of impervious area on the project site. The BMP decision tree for such sites is provided in Figure 2-2 of the USDCM. As 835 Wood Street Drainage Report Page 7 of 7 previously stated, the site and surrounding vicinity is comprised of hydrologic soil group Type B soils, per the NRCS soil survey. The existing storm system should have sufficient capacity for the sites runoff flows as the imperviousness and runoff from the site is less than the historical flows. CONCLUSIONS This Drainage Report for the 835 Wood Street has been prepared to comply with the stormwater criteria set by the City of Fort Collins and the Mile High Flood Control District. The proposed drainage system presented in this report is designed to convey the 100-year peak stormwater runoff through the site via the proposed and existing storm systems. Through calculations, modeling, and review of the proposed storm drain system, there appears to be adequate capacity to convey the proposed flows to the existing storm system. It can therefore be concluded that development of the 835 Wood Street complies with all of the stormwater jurisdictional criteria and will not adversely affect the existing streets, storm drain system and/or detention/water quality facilities. REFERENCES 1. City of Fort Collins Stormwater Criteria Manual, City of Fort Collins, December 2018. 2. “Geotechnical Investigation Proposed CNG Shop Expansion 835 Wood Street Fort Collins, Colorado”, CTL Thompson Incorporated, Dated April 24, 2020. 3. “Urban Storm Drainage Criteria Manual”, Mile High Flood District, August 2018 version. 4. USDA NRCS Web Soil Survey EXISTING BUILDING 835 Wood St, Fort Collins, CO 80521 S89°55'30"W 533.93' S0°04'30"E 276.00' S89°55'30"W 130.00' S0°04'30"E 198.00' N89°55'30"E 663.88'N0°04'07"W 474.00'S0°04'07"E 1327.64'S89°55'30"W 533.93'S0°04'30"E 276.00'S89°55'30"W 130.00'S0°04'30"E 198.00'N89°55'30"E 663.88'N0°04'07"W 474.00'59.66'REVISION DESCRIPTIOND'WNDES'DDATENO.DESIGNED BY: DRAWN BY: CHECKED BY: JOB #: DATE: © JVA, INC.CNG SHOP EXPANSION835 WOOD STREETFORT COLLINS. COSHEET NO. 3256c APRIL 08, 2022 ETN CDH CDH JVA, Inc.213 Linden Street, Suite 200 www.jvajva.com Fort Collins, CO 80524 970.225.9099 Boulder ● Fort Collins ● Winter Park Glenwood Springs ● Denver EXISTING DRAINAGEPLANEDP EXISTING BUILDING 835 Wood St, Fort Collins, CO 80521 S89°55'30"W 533.93' S0°04'30"E 276.00' S89°55'30"W 130.00' S0°04'30"E 198.00' N89°55'30"E 663.88'N0°04'07"W 474.00'S0°04'07"E 1327.64'S89°55'30"W 533.93'S0°04'30"E 276.00'S89°55'30"W 130.00'S0°04'30"E 198.00'N89°55'30"E 663.88'N0°04'07"W 474.00'59.66'REVISION DESCRIPTIOND'WNDES'DDATENO.DESIGNED BY: DRAWN BY: CHECKED BY: JOB #: DATE: © JVA, INC.CNG SHOP EXPANSION835 WOOD STREETFORT COLLINS. COSHEET NO. 3256c APRIL 08, 2022 ETN CDH CDH JVA, Inc.213 Linden Street, Suite 200 www.jvajva.com Fort Collins, CO 80524 970.225.9099 Boulder ● Fort Collins ● Winter Park Glenwood Springs ● Denver PROPOSED DRAINAGEPLANDPP APPENDIX A – REFERENCED INFORMATION VICINITY MAP NOT TO SCALE PROJECT LOCATION Larimer County Area, Colorado 105—Table Mountain loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpty Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Table mountain and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Table Mountain Setting Landform:Stream terraces, flood plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Alluvium Typical profile H1 - 0 to 36 inches: loam H2 - 36 to 60 inches: clay loam Properties and qualities Slope:0 to 1 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.60 to 2.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:15 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum:5.0 Available water supply, 0 to 60 inches: High (about 9.8 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Ecological site: R049XY036CO - Overflow Map Unit Description: Table Mountain loam, 0 to 1 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/2/2022 Page 1 of 2 Hydric soil rating: No Minor Components Caruso Percent of map unit:7 percent Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit:4 percent Landform:Terraces Hydric soil rating: Yes Paoli Percent of map unit:4 percent Hydric soil rating: No Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 16, Sep 2, 2021 Map Unit Description: Table Mountain loam, 0 to 1 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/2/2022 Page 2 of 2 Larimer County Area, Colorado 81—Paoli fine sandy loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpxx Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Paoli and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Paoli Setting Landform:Stream terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Alluvium Typical profile H1 - 0 to 30 inches: fine sandy loam H2 - 30 to 60 inches: fine sandy loam Properties and qualities Slope:0 to 1 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):High (2.00 to 6.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:15 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: A Ecological site: R067BY036CO - Overflow Map Unit Description: Paoli fine sandy loam, 0 to 1 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/2/2022 Page 1 of 2 Hydric soil rating: No Minor Components Caruso Percent of map unit:6 percent Ecological site:R067BY036CO - Overflow Hydric soil rating: No Table mountain Percent of map unit:6 percent Ecological site:R067BY036CO - Overflow Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit:3 percent Landform:Terraces Hydric soil rating: Yes Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 16, Sep 2, 2021 Map Unit Description: Paoli fine sandy loam, 0 to 1 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/2/2022 Page 2 of 2 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 DepthZone 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 mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone 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 8/9/2022 at 4:24 PM 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°5'49"W 40°36'10"N 105°5'11"W 40°35'42"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 400 North Link Lane | Fort Collins, Colorado 80524 Telephone: 970-206-9455 Fax: 970-206-9441 GEOTECHNICAL INVESTIGATION PROPOSED CNG SHOP EXPANSION 835 WOOD STREET FORT COLLINS, COLORADO CITY OF FORT COLLINS 835 Wood Street Fort Collins, Colorado 80521 Attention: Blake Visser Project No. FC09298-125 April 24, 2020 CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 TABLE OF CONTENTS SCOPE 1 SUMMARY OF CONCLUSIONS 1 SITE CONDITIONS AND PROPOSED CONSTRUCTION 2 INVESTIGATION 2 SUBSURFACE CONDITIONS 3 Groundwater 3 SEISMICITY 3 SITE DEVELOPMENT 4 Fill Placement 4 Excavations 5 FOUNDATIONS 5 Footings 5 BELOW GRADE AREAS 6 FLOOR SYSTEMS 7 Exterior Flatwork 9 PAVEMENTS 9 Pavement Selection 10 Subgrade and Pavement Materials and Construction 11 Pavement Maintenance 11 WATER-SOLUBLE SULFATES 11 SURFACE DRAINAGE 12 CONSTRUCTION OBSERVATIONS 12 GEOTECHNICAL RISK 13 LIMITATIONS 13 CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 – SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX A – RESULTS OF LABORATORY TESTING APPENDIX B – SAMPLE SITE GRADING SPECIFICATIONS APPENDIX C – PAVEMENT CONSTRUCTION RECOMMENDATIONS APPENDIX D – PAVEMENT MAINTENANCE PROGRAM CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 1 SCOPE This report presents the results of our Geotechnical Investigation for the proposed CNG shop expansion at 835 Wood Street in Fort Collins, Colorado. The purpose of the investigation was to evaluate the subsurface conditions and provide foundation recommendations and geotechnical design criteria for the project. The scope was described in our Service Agreement (Proposal No. FC-20-0094) dated February 26, 2020. The report was prepared from data developed during field exploration, laboratory testing, engineering analysis and experience with similar conditions. The report includes a description of subsurface conditions found in our exploratory borings and discussions of site development as influenced by geotechnical considerations. Our opinions and recommendations regarding design criteria and construction details for site development, foundations, floor systems, slabs-on- grade, pavements and drainage are provided. The report was prepared for the exclusive use of the City of Fort Collins in design and construction of the proposed improvements. If the proposed construction differs from descriptions herein, we should be requested to review our recommendations. Our conclusions are summarized in the following paragraphs. SUMMARY OF CONCLUSIONS 1. Soils encountered in our borings consisted of 6 to 7 feet of clayey sand overlying sandy gravel to the depths explored. Groundwater was encountered at 10 to 12 feet in two of the borings. Existing groundwater levels are not expected to significantly affect site development. 2. Soft/loose soils were encountered in our borings. If soft soils are encountered, stabilization can likely be achieved by crowding 1½ to 3-inch nominal size crushed rock into the subsoils until the base of the excavation does not deform by more than about 1-inch when compactive effort is applied. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 2 3. Footing foundations placed on natural, undisturbed soil and/or properly compacted fill are recommended for the proposed construction. Design and construction criteria for foundations are presented in the report. 4. We believe a slab-on-grade floor is appropriate for this site. Some movement of slab-on-grade floors should be anticipated. We expect movements will be minor, on the order of 1 inch or less. If movement cannot be tolerated, structural floors should be considered. 5. Surface drainage should be designed, constructed and maintained to provide rapid removal of surface runoff away from the proposed improvements. Conservative irrigation practices should be followed to avoid excessive wetting. 6. Samples of the subgrade soils generally classified as AASHTO A-2- 7. For the parking lot, we recommend 4 inches of hot mix asphalt over 6 inches of aggregate base course. Thicker sections are recommended for areas with heavier traffic. SITE CONDITIONS AND PROPOSED CONSTRUCTION The site is located at 835 Wood Street in Fort Collins, Colorado (Figure 1). The site has a shop building with paved parking areas adjacent to the building. The construction area is relatively flat. Ground cover outside of the existing paved area consists of natural grasses, weeds and trees. There is a pond a few hundred feet to the east. We understand the proposed expansion will include a 6,000 square foot addition on the northwest side of the existing shop building. Pavements surrounding the addition will be reconstructed where destroyed during construction and additional areas may be paved. INVESTIGATION The field investigation included drilling four exploratory borings at the locations presented on Figure 1. The borings were drilled to depths of approximately 10 to 20 feet using 4-inch diameter, continuous-flight augers and a CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 3 truck-mounted drill. Drilling was observed by our field representative who logged the soils. Summary logs of the borings, including results of field penetration resistance tests, are presented on Figure 2. Soil samples obtained during drilling were returned to our laboratory and visually examined by our geotechnical engineer. Laboratory testing was assigned and included moisture content, dry density, swell-consolidation, particle-size analysis and water-soluble sulfate tests. Swell-consolidation test samples were wetted at a confining pressure which approximated the pressure exerted by the overburden soils (overburden pressures). Results of the laboratory tests are presented in Appendix A and summarized in Table A-I. SUBSURFACE CONDITIONS Soils encountered in our borings consisted of 6 to 7 feet of clayey sand overlying sandy gravel to the depths explored. Swell-consolidation testing of the clayey sand indicated nil to 0.1 percent swell potential. The gravel is non- expansive. Bedrock was not encountered during the investigation. Further descriptions of the subsurface conditions are presented on our boring logs and in our laboratory test results. Groundwater Groundwater was encountered at 10 to 12 feet in two of the borings. Groundwater levels will fluctuate seasonally. Groundwater is not expected to affect construction at the site. We recommend a minimum separation of 3 feet from groundwater to foundations and floor systems. SEISMICITY This area, like most of central Colorado, is subject to a low degree of seismic risk. As in most areas of recognized low seismicity, the record of the past CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 4 earthquake activity in Colorado is incomplete. According to the 2015 International Building Code and the subsurface conditions encountered in our borings, this site probably classifies as a Site Class D. Only minor damage to relatively new, properly designed and built buildings would be expected. Wind loads, not seismic considerations, typically govern dynamic structural design for the structures planned in this area. SITE DEVELOPMENT Fill Placement The existing onsite soils are suitable for re-use as fill material provided debris or deleterious organic materials are removed. If import material is used, it should be tested and approved as acceptable fill by CTL|Thompson. In general, import fill should meet or exceed the engineering qualities of the onsite soils. Areas to receive fill should be scarified, moisture-conditioned and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D698, AASHTO T99). Stabilization can likely be achieved by crowding 1½ to 3-inch nominal size crushed rock into the subsoils until the base of the excavation does not deform by more than about 1-inch when compactive effort is applied. Sand soils used as fill should be moistened to within 2 percent of optimum moisture content. Clay soils should be moistened between optimum and 3 percent above optimum moisture content. The fill should be moisture-conditioned, placed in thin, loose lifts (8 inches or less) and compacted as described above. We should observe placement and compaction of fill during construction. Fill placement and compaction should not be conducted when the fill material is frozen. Site grading in areas of landscaping where no future improvements are planned can be placed at a dry density of at least 90 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Example site grading specifications are presented in Appendix B. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 5 Excavations We believe the materials found in our borings can be excavated using conventional excavation equipment. Excavations should be sloped or shored to meet local, State and Federal safety regulations. Based on our investigation and OSHA standards, we believe the granular soils classify as Type C soils. Type C soils require a maximum slope inclination of 1.5:1 in dry conditions. Excavation slopes specified by OSHA are dependent upon types of soil and groundwater conditions encountered. The contractor’s “competent person” should identify the soils and/or rock encountered in the excavation and refer to OSHA standards to determine appropriate slopes. Stockpiles of soils, rock, equipment, or other items should not be placed within a horizontal distance equal to one-half the excavation depth, from the edge of excavation. Excavations deeper than 20 feet should be braced or a professional engineer should design the slopes. FOUNDATIONS Our investigation indicates non-expansive to slightly expansive soils are present at the anticipated foundation levels. Footing foundations are recommended for the proposed construction. Design criteria for footing foundations developed from analysis of field and laboratory data and our experience are presented below. Footings 1. Footings should be constructed on undisturbed natural soils or properly compacted fill (see the Fill Placement section of this report). All existing, uncontrolled fill should be removed from under footings and within one footing width around footings and replaced with properly compacted fill. Where soil is loosened during excavation, it should be removed and replaced with compacted fill. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 6 2. Soft soils were encountered in our borings. If soft soils are encountered, stabilization can likely be achieved by crowding 1½ to 3-inch nominal size crushed rock into the subsoils until the base of the excavation does not deform by more than about 1-inch when compactive effort is applied. 3. Footings should be designed for a net allowable soil pressure of 1,500 psf. The soil pressure can be increased 33 percent for transient loads such as wind or seismic loads. 4. Footings should have a minimum width of at least 18 inches. Foundations for isolated columns should have minimum dimensions of 24 inches by 24 inches. Larger sizes may be required depending on loads and the structural system used. 5. The soils beneath footing pads can be assigned an ultimate coefficient of friction of 0.4 to resist lateral loads. The ability of grade beam or footing backfill to resist lateral loads can be calculated using a passive equivalent fluid pressure of 250 pcf. This assumes the backfill is densely compacted and will not be removed. Deflection of grade beams is necessary to mobilize passive earth pressure; we recommend a factor of safety of 2 for this condition. Backfill should be placed and compacted to the criteria in the Fill Placement section of this report. 6. Exterior footings should be protected from frost action. We believe 30 inches of frost cover is appropriate for this site. 7. Foundation walls and grade beams should be well reinforced both top and bottom. We recommend reinforcement sufficient to simply span 10 feet. The reinforcement should be designed by a structural engineer. 8. We should observe completed footing excavations to confirm whether the subsurface conditions are similar to those found in our borings. BELOW GRADE AREAS No below grade areas are planned for the buildings. For this condition, perimeter drains are not usually necessary. We should be contacted to provide foundation drain recommendations if plans change to include below grade areas. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 7 FLOOR SYSTEMS In our opinion, it is reasonable to use slab-on-grade floors for the proposed construction. Any fill placed for the floor subgrade should be built with densely compacted, engineered fill as discussed in the Fill Placement section of this report. It is impossible to construct slab-on-grade floors with no risk of movement. We believe movements due to swell will be less than 1 inch at this site. If movement cannot be tolerated, structural floors should be used. Structural floors can be considered for specific areas that are particularly sensitive to movement or where equipment on the floor is sensitive to movement. Where structurally supported floors are selected, we recommend a minimum void between the ground surface and the underside of the floor system of 4 inches. The minimum void should be constructed below beams and utilities that penetrate the floor. The floor may be cast over void form. Void form should be chosen to break down quickly after the slab is placed. We recommend against the use of wax or plastic-coated void boxes. Slabs may be subject to heavy point loads. The structural engineer should design floor slab reinforcement. For design of slabs-on-grade, we recommend a modulus of subgrade reaction of 100 pci for on-site soils. If the owner elects to use slab-on-grade construction and accepts the risk of movement and associated damage, we recommend the following precautions for slab-on-grade construction at this site. These precautions can help reduce, but not eliminate, damage or distress due to slab movement. 1. Slabs should be separated from exterior walls and interior bearing members with a slip joint that allows free vertical movement of the slabs. This can reduce cracking if some movement of the slab occurs. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 8 2. Slabs should be placed directly on exposed soils or properly moisture conditioned, compacted fill. The 2019 International Building Code (IBC) requires a vapor retarder be placed between the base course or subgrade soils and the concrete slab-on-grade floor. The merits of installation of a vapor retarder below floor slabs depend on the sensitivity of floor coverings and building use to moisture. A properly installed vapor retarder (minimum 6-mil; 10-mil recommended) is more beneficial below concrete slab-on-grade floors where floor coverings, painted floor surfaces or products stored on the floor will be sensitive to moisture. The vapor retarder is most effective when concrete is placed directly on top of it, rather than placing a sand or gravel leveling course between the vapor retarder and the floor slab. The placement of concrete on the vapor retarder may increase the risk of shrinkage cracking and curling. Use of concrete with reduced shrinkage characteristics including minimized water content, maximized coarse aggregate content, and reasonably low slump will reduce the risk of shrinkage cracking and curling. Considerations and recommendations for the installation of vapor retarders below concrete slabs are outlined in Section 3.2.3 of the 2006 report of American Concrete Institute (ACI) Committee 302, “Guide for Concrete Floor and Slab Construction (ACI 302.R1-04)”. 3. If slab-bearing partitions are used, they should be designed and constructed to allow for slab movement. At least a 2-inch void should be maintained below or above the partitions. If the “float” is provided at the top of partitions, the connection between interior, slab- supported partitions and exterior, foundation supported walls should be detailed to allow differential movement. 4. Underslab plumbing should be eliminated where feasible. Where such plumbing is unavoidable it should be thoroughly pressure tested for leaks prior to slab construction and be provided with flexible couplings. Pressurized water supply lines should be brought above the floors as quickly as possible. 5. Plumbing and utilities that pass through the slabs should be isolated from the slabs and constructed with flexible couplings. Where water and gas lines are connected to furnaces or heaters, the lines should be constructed with sufficient flexibility to allow for movement. 6. HVAC equipment supported on the slab should be provided with a collapsible connection between the furnace and the ductwork, with allowance for at least 2 inches of vertical movement. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 9 7. The American Concrete Institute (ACI) recommends frequent control joints be provided in slabs to reduce problems associated with shrinkage cracking and curling. To reduce curling, the concrete mix should have a high aggregate content and a low slump. If desired, a shrinkage compensating admixture could be added to the concrete to reduce the risk of shrinkage cracking. We can perform a mix design or assist the design team in selecting a pre-existing mix. Exterior Flatwork We recommend exterior flatwork and sidewalks be isolated from foundations to reduce the risk of transferring heave, settlement or freeze-thaw movement to the structure. One alternative would be to construct the inner edges of the flatwork on haunches or steel angles bolted to the foundation walls and detailing the connections such that movement will cause less distress to the building, rather than tying the slabs directly into the building foundation. Construction on haunches or steel angles and reinforcing the sidewalks and other exterior flatwork will reduce the potential for differential settlement and better allow them to span across wall backfill. Frequent control joints should be provided to reduce problems associated with shrinkage. Panels that are approximately square perform better than rectangular areas. PAVEMENTS The project will include paved parking. The performance of pavements is dependent upon the characteristics of the subgrade soil, traffic loading and frequency, climatic conditions, drainage and pavement materials. We drilled two exploratory borings and conducted laboratory tests to characterize the subgrade soils, which consisted of clayey sand. The subgrade soils classified as A-2-7 soils in accordance with AASHTO procedures. The subgrade soil will likely provide fair to poor support for new pavement. If fill is needed, we have assumed it will be soils with similar or better characteristics. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 10 Flexible hot mix asphalt (HMA) over aggregate base course (ABC) is likely planned for pavement areas. Rigid Portland cement concrete (PCC) pavement should be used for trash enclosure areas and where the pavement will be subjected to frequent turning of heavy vehicles. Our designs are based on the AASHTO design method and our experience. Using the criteria discussed above we recommend the minimum pavement sections provided in Table A. TABLE A RECOMMENDED PAVEMENT SECTIONS Classification Hot Mix Asphalt (HMA) + Aggregate Base Course (ABC) Portland Cement Concrete (PCC) Parking Area 4" HMA + 6" ABC 5" PCC Access Drives / Heavy Traffic Areas 5" HMA + 6" ABC 6" PCC Trash Enclosures - 6" PCC Pavement Selection Composite HMA/ABC pavement over a stable subgrade is expected to perform well at this site based on the recommendations provided. HMA provides a stiff, stable pavement to withstand heavy loading and will provide a good fatigue resistant pavement. However, HMA does not perform well when subjected to point loads in areas where heavy trucks turn and maneuver at slow speeds. PCC pavement is expected to perform well in this area; PCC pavement has better performance in freeze-thaw conditions and should require less long-term maintenance than HMA pavement. The PCC pavement for trash enclosures should extend out to areas where trash trucks park to lift and empty dumpsters. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 11 Subgrade and Pavement Materials and Construction The design of a pavement system is as much a function of the quality of the paving materials and construction as the support characteristics of the subgrade. The construction materials are assumed to possess sufficient quality as reflected by the strength factors used in our design calculations. Moisture treatment criteria and additional criteria for materials and construction requirements are presented in Appendix C of this report. Pavement Maintenance Routine maintenance, such as sealing and repair of cracks, is necessary to achieve the long-term life of a pavement system. We recommend a preventive maintenance program be developed and followed for all pavement systems to assure the design life can be realized. Choosing to defer maintenance usually results in accelerated deterioration leading to higher future maintenance costs, and/or repair. A recommended maintenance program is outlined in Appendix D. Excavation of completed pavement for utility construction or repair can destroy the integrity of the pavement and result in a severe decrease in serviceability. To restore the pavement top original serviceability, careful backfill compaction before repaving is necessary. WATER-SOLUBLE SULFATES Concrete that comes into contact with soils can be subject to sulfate attack. We measured water-soluble sulfate concentrations in two samples from this site. Concentrations were below measurable limits. Sulfate concentrations less than 0.1 percent indicate Class 0 exposure to sulfate attack for concrete that comes into contact with the subsoils, according to the American Concrete Institute (ACI). For this level of sulfate concentration, ACI indicates there are no special requirements for sulfate resistance. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 12 Superficial damage may occur to the exposed surfaces of highly permeable concrete, even though sulfate levels are relatively low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drainage or high water tables. Concrete should have a total air content of 6 percent ± 1.5 percent. We advocate all foundation walls and grade beams in contact with the soil (including the inside and outside faces of garage and crawl space grade beams) be damp-proofed. SURFACE DRAINAGE Performance of foundations, flatwork and pavements are influenced by changes in subgrade moisture conditions. Carefully planned and maintained surface grading can reduce the risk of wetting of the foundation soils and pavement subgrade. We recommend a minimum slope of 5 percent in the first ten feet outside foundations in landscaped areas. Backfill around foundations should be moisture treated and compacted as described in Fill Placement. Roof drains should be directed away from buildings. Downspout extensions and splash blocks should be provided at discharge points, or roof drains should be connected to solid pipe discharge systems. We do not recommend directing roof drains under buildings. CONSTRUCTION OBSERVATIONS We recommend that CTL | Thompson, Inc. provide construction observation services to allow us the opportunity to verify whether soil conditions are consistent with those found during this investigation. Other observations are recommended to review general conformance with design plans. If others perform these observations, they must accept responsibility to judge whether the recommendations in this report remain appropriate. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 13 GEOTECHNICAL RISK The concept of risk is an important aspect with any geotechnical evaluation primarily because the methods used to develop geotechnical recommendations do not comprise an exact science. We never have complete knowledge of subsurface conditions. Our analysis must be tempered with engineering judgment and experience. Therefore, the recommendations presented in any geotechnical evaluation should not be considered risk-free. Our recommendations represent our judgment of those measures that are necessary to increase the chances that the structures will perform satisfactorily. It is critical that all recommendations in this report are followed during construction. Owners must assume responsibility for maintaining the structures and use appropriate practices regarding drainage and landscaping. Improvements performed by owners after construction, such as construction of additions, retaining walls, landscaping and exterior flatwork, should be completed in accordance with recommendations in this report. LIMITATIONS This report has been prepared for the exclusive use of City of Fort Collins for the purpose of providing geotechnical design and construction criteria for the proposed project. The information, conclusions, and recommendations presented herein are based upon consideration of many factors including, but not limited to, the type of construction proposed, the geologic setting, and the subsurface conditions encountered. The conclusions and recommendations contained in the report are not valid for use by others. Standards of practice evolve in the area of geotechnical engineering. The recommendations provided are appropriate for about three years. If the proposed construction is not constructed within about three years, we should be contacted to determine if we should update this report. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 14 Four borings were drilled during this investigation to obtain a reasonably accurate picture of the subsurface conditions. Variations in the subsurface conditions not indicated by our borings are possible. A representative of our firm should observe foundation excavations to confirm the exposed materials are as anticipated from our borings. We believe this investigation was conducted with that level of skill and care ordinarily used by geotechnical engineers practicing under similar conditions. No warranty, express or implied, is made. If we can be of further service in discussing the contents of this report or in the analysis of the influence of subsurface conditions on design of the structures, please call. CTLTHOMPSON, INC. Trace Krausse, EI Spencer Schram, PE Project Geotechnical Engineer Project Engineer TSK:SAS TH-3 TH-2 TH-1 TH-4 Wood StreetSITE SYCAMORE ST.WOOD ST.VINE DR.TAFT HILL RD.ELM ST. LEGEND: INDICATES APPROXIMATE LOCATION OF EXPLORATORY BORING TH-1 CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL I T PROJECT NO. FC09298-125 FIGURE 1 Locations of Exploratory Borings VICINITY MAP FORT COLLINS, COLORADO NOT TO SCALE 100' APPROXIMATE SCALE: 1" = 100' 50'0' 0 5 10 15 20 25 30 35 40DEPTH - FEETSummary Logs of Exploratory Borings FIGURE 2 CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL | T PROJECT NO. FC09298-125 3/12 15/12 50/6 WC=13.0 DD=105 SW=0.0 WC=4.8 -200=4 TH-1 4/12 40/12 WC=16.8 DD=111 SW=0.0 SS=<0.01 WC=3.6 -200=5 TH-2 6/12 41/12 WC=6.9 DD=102 SW=0.1 TH-3 6/12 50/6 WC=7.5 DD=106 -200=33 TH-4 1. NOTES: DRIVE SAMPLE. THE SYMBOL 3/12 INDICATES 3 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. INDICATES MOISTURE CONTENT (%). INDICATES DRY DENSITY (PCF). INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%). INDICATES PASSING NO. 200 SIEVE (%). INDICATES SOLUBLE SULFATE CONTENT (%). THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. SAND, CLAYEY, MOIST, VERY LOOSE TO LOOSE, BROWN (SC) 3. LEGEND: GRAVEL, SANDY, MOIST TO WET, MEDIUM DENSE TO DENSE, BROWN (GP) - - - - - THE BORINGS WERE DRILLED ON MARCH 30, 2020 USING 4-INCH DIAMETER CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG. 2. WC DD SW -200 SS ASPHALTIC CONCRETE (AC) WATER LEVEL MEASURED AT TIME OF DRILLING. 0 5 10 15 20 25 30 35 40 DEPTH - FEET5/12 4/12 WC=7.5 -200=20 6/12 WC=14.5 DD=106 LL=25 PI=7 -200=50 5" AC 4.5 " AC APPENDIX A RESULTS OF LABORATORY TESTING Sample of SAND, CLAYEY (SC) DRY UNIT WEIGHT=102 PCF From TH - 3 AT 2 FEET MOISTURE CONTENT=6.9 % Sample of SAND, CLAYEY (SC) DRY UNIT WEIGHT=105 PCF From TH - 1 AT 4 FEET MOISTURE CONTENT=13.0 % CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL | T PROJECT NO. FC09298-125 APPLIED PRESSURE -KSF APPLIED PRESSURE -KSFCOMPRESSION % EXPANSIONSwell Consolidation Test Results FIGURE A-1COMPRESSION % EXPANSION-4 -3 -2 -1 0 1 2 3 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING -4 -3 -2 -1 0 1 2 3 NO MOVEMENT DUE TO WETTING 0.1 1.0 10 100 0.1 1.0 10 100 Sample of SAND, CLAYEY (SC) DRY UNIT WEIGHT=111 PCF From TH - 2 AT 2 FEET MOISTURE CONTENT=16.8 % CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL | T PROJECT NO. FC09298-125 APPLIED PRESSURE -KSFCOMPRESSION % EXPANSIONSwell Consolidation Test Results FIGURE A-2 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 NO MOVEMENT DUE TO WETTING 0.1 1.0 10 100 Sample of GRAVEL, SANDY (GP)GRAVEL 51 %SAND 45 % From TH - 1 AT 14 FEET SILT & CLAY 4 %LIQUID LIMIT % PLASTICITY INDEX % Sample of GRAVEL, SANDY (GP)GRAVEL 51 %SAND 44 % From TH - 2 AT 9 FEET SILT & CLAY 5 %LIQUID LIMIT % PLASTICITY INDEX % CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL | T PROJECT NO. FC09298-125 FIGURE A-3 Gradation Test Results 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC)SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR.7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING0 10 20 30 50 60 70 80 90 100 PERCENT RETAINED40 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC)SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR.7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSINGPERCENT RETAINED0 10 20 30 40 50 60 70 80 90 100 Sample of SAND, CLAYEY (SC)GRAVEL 4 %SAND 76 % From TH - 3 AT 4 FEET SILT & CLAY 20 %LIQUID LIMIT % PLASTICITY INDEX % Sample of SAND, CLAYEY (SC)GRAVEL 3 %SAND 64 % From TH - 4 AT 2 FEET SILT & CLAY 33 %LIQUID LIMIT % PLASTICITY INDEX % CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL | T PROJECT NO. FC09298-125 FIGURE A-4 Gradation Test Results 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC)SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR.7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING0 10 20 30 50 60 70 80 90 100 PERCENT RETAINED40 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC)SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR.7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSINGPERCENT RETAINED0 10 20 30 40 50 60 70 80 90 100 PASSING WATER- MOISTURE DRY LIQUID PLASTICITY APPLIED NO. 200 SOLUBLE DEPTH CONTENT DENSITY LIMIT INDEX SWELL*PRESSURE SIEVE SULFATES BORING (FEET)(%)(PCF)(%)(PSF)(%)(%)DESCRIPTION TH-3 2 6.9 102 0.1 150 SAND, CLAYEY (SC) TH-1 4 13.0 105 0.0 500 SAND, CLAYEY (SC) TH-1 14 4.8 4 GRAVEL, SANDY (GP) TH-2 2 16.8 111 0.0 500 <0.01 SAND, CLAYEY (SC) TH-2 9 3.6 5 GRAVEL, SANDY (GP) TH-3 2 <0.01 SAND, CLAYEY (SC) TH-3 4 7.5 20 SAND, CLAYEY (SC) TH-4 2 7.5 106 33 SAND, CLAYEY (SC) TH-4 4 14.5 106 25 7 50 SAND, CLAYEY (SC) SWELL TEST RESULTS* TABLE A-I SUMMARY OF LABORATORY TESTING ATTERBERG LIMITS Page 1 of 1 * NEGATIVE VALUE INDICATES COMPRESSION. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTL|T PROJECT NO. FC09298-125 APPENDIX B SAMPLE SITE GRADING SPECIFICATIONS CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 B-1 SAMPLE SITE GRADING SPECIFICATIONS 1. DESCRIPTION This item shall consist of the excavation, transportation, placement and compaction of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve building site elevations. 2. GENERAL The Geotechnical Engineer shall be the Owner's representative. The Geotechnical Engineer shall approve fill materials, method of placement, moisture contents and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE The Contractor shall remove all trees, brush and rubbish before excavation or fill placement is begun. The Contractor shall dispose of the cleared material to provide the Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill or where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed from the ground surface upon which fill is to be placed. The surface shall then be plowed or scarified to a depth of 8 inches until the surface is free from ruts, hummocks or other uneven features, which would prevent uniform compaction by the equipment to be used. 5. COMPACTING AREA TO BE FILLED After the foundation for the fill has been cleared and scarified, it shall be disked or bladed until it is free from large clods, brought to the proper moisture content and compacted to not less than 95 percent of maximum dry density as determined in accordance with ASTM D 698 or AASHTO T 99. 6. FILL MATERIALS On-site materials classifying as CL, SC, SM, SW, SP, GP, GC and GM are acceptable. Fill soils shall be free from organic matter, debris, or other deleterious substances, and shall not contain rocks or lumps having a diameter greater than three (3) inches. Fill materials shall be obtained from the existing fill and other approved sources. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 B-2 7. MOISTURE CONTENT Fill materials shall be moisture treated. Clay soils placed below the building envelope should be moisture-treated to between optimum and 3 percent above optimum moisture content as determined from Standard Proctor compaction tests. Clay soil placed exterior to the building should be moisture treated between optimum and 3 percent above optimum moisture content. Sand soils can be moistened to within 2 percent of optimum moisture content. Sufficient laboratory compaction tests shall be performed to determine the optimum moisture content for the various soils encountered in borrow areas. The Contractor may be required to add moisture to the excavation materials in the borrow area if, in the opinion of the Geotechnical Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. The Contractor may be required to rake or disk the fill soils to provide uniform moisture content through the soils. The application of water to embankment materials shall be made with any type of watering equipment approved by the Geotechnical Engineer, which will give the desired results. Water jets from the spreader shall not be directed at the embankment with such force that fill materials are washed out. Should too much water be added to any part of the fill, such that the material is too wet to permit the desired compaction from being obtained, rolling and all work on that section of the fill shall be delayed until the material has been allowed to dry to the required moisture content. The Contractor will be permitted to rework wet material in an approved manner to hasten its drying. 8. COMPACTION OF FILL AREAS Selected fill material shall be placed and mixed in evenly spread layers. After each fill layer has been placed, it shall be uniformly compacted to not less than the specified percentage of maximum dry density. Fill materials shall be placed such that the thickness of loose material does not exceed 8 inches and the compacted lift thickness does not exceed 6 inches. Fill placed under foundations, exterior flatwork and pavements should be compacted to a minimum of 95 percent of maximum standard Proctor dry density (ASTM D698). Compaction, as specified above, shall be obtained by the use of sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other equipment approved by the Engineer. Compaction shall be accomplished while the fill material is at the specified moisture content. Compaction of each layer shall be continuous over the entire area. Compaction equipment shall make sufficient trips to insure that the required dry density is obtained. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 B-3 9. COMPACTION OF SLOPES Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but not too dense for planting, and there is no appreciable amount of loose soil on the slopes. Compaction of slopes may be done progressively in increments of three to five feet (3' to 5') in height or after the fill is brought to its total height. Permanent fill slopes shall not exceed 3:1 (horizontal to vertical). 10. DENSITY TESTS Field density tests shall be made by the Geotechnical Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density tests shall be taken in compacted material below the disturbed surface. When density tests indicate that the dry density or moisture content of any layer of fill or portion thereof is below that required, the particular layer or portion shall be reworked until the required dry density or moisture content has been achieved. 11. SEASONAL LIMITS No fill material shall be placed, spread or rolled while it is frozen, thawing, or during unfavorable weather conditions. When work is interrupted by heavy precipitation, fill operations shall not be resumed until the Geotechnical Engineer indicates that the moisture content and dry density of previously placed materials are as specified. 12. NOTICE REGARDING START OF GRADING The contractor shall submit notification to the Geotechnical Engineer and Owner advising them of the start of grading operations at least three (3) days in advance of the starting date. Notification shall also be submitted at least 3 days in advance of any resumption dates when grading operations have been stopped for any reason other than adverse weather conditions. 13. REPORTING OF FIELD DENSITY TESTS Density tests performed by the Geotechnical Engineer, as specified under "Density Tests" above, shall be submitted progressively to the Owner. Dry density, moisture content and percent compaction shall be reported for each test taken. APPENDIX C PAVEMENT CONSTRUCTION RECOMMENDATIONS CITY OF FORT COLLINS 835 WOOD STREET EXPANSION CTLT PROJECT NO. FC09298-125 C-1 SUBGRADE PREPARATION Moisture Treated Subgrade (MTS) 1. The subgrade should be stripped of organic matter, scarified, moisture treated and compacted to the specifications stated below in Item 2. The compacted subgrade should extend at least 3 feet beyond the edge of the pavement where no edge support, such as curb and gutter, are to be constructed. 2. Sandy and gravelly soils (A-1-a, A-1-b, A-3, A-2-4, A-2-5, A-2-6, A- 2-7) should be moisture conditioned near optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Clayey soils (A-6, A-7-5, A-7-6) should be moisture conditioned between optimum and 3 percent above optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 3. Utility trenches and all subsequently placed fill should be properly compacted and tested prior to paving. As a minimum, fill should be compacted to 95 percent of standard Proctor maximum dry density. 4. Final grading of the subgrade should be carefully controlled so the design cross-slope is maintained and low spots in the subgrade that could trap water are eliminated. 5. Once final subgrade elevation has been compacted and tested to compliance and shaped to the required cross-section, the area should be proof-rolled using a minimum axle load of 18 kips per axle. The proof-roll should be performed while moisture contents of the subgrade are still within the recommended limits. Drying of the subgrade prior to proof-roll or paving should be avoided. 6. Areas that are observed by the Engineer that have soft spots in the subgrade, or where deflection is not uniform of soft or wet subgrade shall be ripped, scarified, dried or wetted as necessary and recompacted to the requirements for the density and moisture. As an alternative, those areas may be sub-excavated and replaced with properly compacted structural backfill. Where extensively soft, yielding subgrade is encountered; we recommend a representative of our office observe the excavation. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 C-2 PAVEMENT MATERIALS AND CONSTRUCTION Aggregate Base Course (ABC) 1. A Class 5 or 6 Colorado Department of Transportation (CDOT) specified ABC should be used. A reclaimed concrete pavement (RCP) alternative which meets the Class 5 or 6 designation and design R-value/strength coefficient is also acceptable. Blending of recycled products with ABC may be considered. 2. Bases should have a minimum Hveem stabilometer value of 72, or greater. ABC, RAP, RCP, or blended materials must be moisture stable. The change in R-value from 300-psi to 100-psi exudation pressure should be 12 points or less. 3. ABC or RCP bases should be placed in thin lifts not to exceed 6 inches and moisture treated to near optimum moisture content. Bases should be moisture treated to near optimum moisture content, and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 4. Placement and compaction of ABC or RCP should be observed and tested by a representative of our firm. Placement should not commence until the underlying subgrade is properly prepared and tested. Hot Mix Asphalt (HMA) 1. HMA should be composed of a mixture of aggregate, filler, hydrated lime, and asphalt cement. Some mixes may require polymer modified asphalt cement, or make use of up to 20 percent reclaimed asphalt pavement (RAP). A job mix design is recommended and periodic checks on the job site should be made to verify compliance with specifications. 2. HMA should be relatively impermeable to moisture and should be designed with crushed aggregates that have a minimum of 80 percent of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. 3. Gradations that approach the maximum density line (within 5 percent between the No. 4 and 50 sieves) should be avoided. A gradation with a nominal maximum size of 1 or 2 inches developed on the fine side of the maximum density line should be used. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 C-3 4. Total void content, voids in the mineral aggregate (VMA) and voids filled should be considered in the selection of the optimum asphalt cement content. The optimum asphalt content should be selected at a total air void content of approximately 4 percent. The mixture should have a minimum VMA of 14 percent and between 65 percent and 80 percent of voids filled. 5. Asphalt cement should meet the requirements of the Superpave Performance Graded (PG) Binders. The minimum performing asphalt cement should conform to the requirements of the governing agency. 6. Hydrated lime should be added at the rate of 1 percent by dry weight of the aggregate and should be included in the amount passing the No. 200 sieve. Hydrated lime for aggregate pretreatment should conform to the requirements of ASTM C 207, Type N. 7. Paving should be performed on properly prepared, unfrozen surfaces that are free of water, snow and ice. Paving should only be performed when both air and surface temperatures equal, or exceed, the temperatures specified in Table 401-3 of the 2006 Colorado Department of Transportation Standard Specifications for Road and Bridge Construction. 8. HMA should not be placed at a temperature lower than 245oF for mixes containing PG 64-22 asphalt, and 290oF for mixes containing polymer-modified asphalt. The breakdown compaction should be completed before the HMA temperature drops 20oF. 9. Wearing surface course shall be Grading S or SX for residential roadway classifications and Grading S for collector, arterial, industrial, and commercial roadway classifications. 10. The minimum/maximum lift thicknesses for Grade SX shall be 1½ inches/2½ inches. The minimum/maximum lift thicknesses for Grade S shall be 2 inches/3½ inches. The minimum/maximum lift thicknesses for Grade SG shall be 3 inches/5 inches. 11. Joints should be staggered. No joints should be placed within wheel paths. 12. HMA should be compacted to between 92 and 96 percent of Maximum Theoretical Density. The surface shall be sealed with a finish roller prior to the mix cooling to 185oF. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 C-4 13. Placement and compaction of HMA should be observed and tested by a representative of our firm. Placement should not commence until approval of the proof rolling as discussed in the Subgrade Preparation section of this report. Subbase, base course or initial pavement course shall be placed within 48 hours of approval of the proof rolling. If the Contractor fails to place the subbase, base course or initial pavement course within 48 hours or the condition of the subgrade changes due to weather or other conditions, proof rolling and correction shall be performed again. Portland Cement Concrete (PCC) 1. Portland cement concrete should consist of Class P of the 2019 CDOT - Standard Specifications for Road and Bridge Construction specifications for normal placement or Class E for fast-track projects. PCC should have a minimum compressive strength of 4,200 psi at 28 days and a minimum modulus of rupture (flexural strength) of 650 psi. Job mix designs are recommended and periodic checks on the job site should be made to verify compliance with specifications. 2. Portland cement should be Type II “low alkali” and should conform to ASTM C 150. 3. Portland cement concrete should not be placed when the subgrade or air temperature is below 40°F. 4. Concrete should not be placed during warm weather if the mixed concrete has a temperature of 90°F, or higher. 5. Mixed concrete temperature placed during cold weather should have a temperature between 50°F and 90°F. 6. Free water should not be finished into the concrete surface. Atomizing nozzle pressure sprayers for applying finishing compounds are recommended whenever the concrete surface becomes difficult to finish. 7. Curing of the Portland cement concrete should be accomplished by the use of a curing compound. The curing compound should be applied in accordance with manufacturer recommendations. 8. Curing procedures should be implemented, as necessary, to protect the pavement against moisture loss, rapid temperature change, freezing, and mechanical injury. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 C-5 9. Construction joints, including longitudinal joints and transverse joints, should be formed during construction or sawed after the concrete has begun to set, but prior to uncontrolled cracking. 10. All joints should be properly sealed using a rod back-up and approved epoxy sealant. 11. Traffic should not be allowed on the pavement until it has properly cured and achieved at least 80 percent of the design strength, with saw joints already cut. 12. Placement of Portland cement concrete should be observed and tested by a representative of our firm. Placement should not commence until the subgrade is properly prepared and tested. APPENDIX D PAVEMENT MAINTENANCE PROGRAM CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 D-1 MAINTENANCE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS A primary cause for deterioration of pavements is oxidative aging resulting in brittle pavements. Tire loads from traffic are necessary to "work" or knead the asphalt concrete to keep it flexible and rejuvenated. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal or rejuvenating the asphalt binder to extend pavement life. 1. Annual Preventive Maintenance a. Visual pavement evaluations should be performed each spring or fall. b. Reports documenting the progress of distress should be kept current to provide information on effective times to apply preventive maintenance treatments. c. Crack sealing should be performed annually as new cracks appear. 2. 3 to 5 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 3 to 5 years to reduce oxidative embrittlement problems. b. Typical preventive maintenance treatments include chip seals, fog seals, slurry seals and crack sealing. 3. 5 to 10 Year Corrective Maintenance a. Corrective maintenance may be necessary, as dictated by the pavement condition, to correct rutting, cracking and structurally failed areas. b. Corrective maintenance may include full depth patching, milling and overlays. c. In order for the pavement to provide a 20-year service life, at least one major corrective overlay should be expected. CITY OF FORT COLLINS 835 WOOD STREET CNG SHOP EXPANSION CTLT PROJECT NO. FC09298-125 D-2 MAINTENANCE RECOMMENDATIONS FOR RIGID PAVEMENTS High traffic volumes create pavement rutting and smooth polished surfaces. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal and improving skid resistance through a new wearing course. 1. Annual Preventive Maintenance a. Visual pavement evaluations should be performed each spring or fall. b. Reports documenting the progress of distress should be kept current to provide information of effective times to apply preventive maintenance. c. Crack sealing should be performed annually as new cracks appear. 2. 4 to 8 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 4 to 8 years to reduce joint deterioration. b. Typical preventive maintenance for rigid pavements includes patching, crack sealing and joint cleaning and sealing. c. Where joint sealants are missing or distressed, resealing is mandatory. 3. 15 to 20 Year Corrective Maintenance a. Corrective maintenance for rigid pavements includes patching and slab replacement to correct subgrade failures, edge damage, and material failure. b. Asphalt concrete overlays may be required at 15 to 20 year intervals to improve the structural capacity of the pavement. APPENDIX B – HYDROLOGIC/HYDRAULIC COMPUTATIONS JVA Incorporated Job Name: Fort Collins CNG I% C2 C5 C10 C100 1319 Spruce Street Job Number: 3256c Streets Paved 100% 0.95 0.00 0.95 1.00 Boulder, CO 80302 Date: 12/20/22 Concrete Drives/Walks 90% 0.95 0.00 0.95 1.00 Ph: (303) 444 1951 By: CDH Roof 90% 0.95 0.00 0.95 1.00 Gravel 40% 0.50 0.00 0.50 0.63 Landscaping (B soil) 0% 0.15 0.00 0.15 0.19 Fort Collins CNG Landscaping (C/D soil) 0% 0.25 0.00 0.25 0.31 Historic Runoff Coefficient & Time of Concentration Calculations Playground 10% 0.11 0.00 0.11 0.14 Location: Fort_Collins Artificial Turf 25% 0.20 0.00 0.20 0.25 Minor Design Storm: 2 Major Design Storm: 100 Soil Type: B Basin Design Data I (%) = 100% 90% 90% 40% 10% 25% 0% 0%I (%)tc Comp tc Final Basin Name Design Point Apaved streets (sf) Adrives/co nc (sf) Aroof (sf) Agravel (sf) Aplygnd (sf) Aart. turf (sf) Alscape (B soil) (sf) Alscape (C/D soil) (sf) ATotal (sf) ATotal (ac) Imp (%)C2 C5 C10 C100 Upper most Length (ft) Slope (%) ti (min) Length (ft) Slope (%)Type of Land Surface K Velocity (fps) tt (min) Time of Conc ti + tt = tc Total Length (ft) tc=(L/180)+ 10 (min.) Min tc E1 1 77,813 10,708 19,624 11,275 74,906 194,325 4.46 56.4% 0.62 0.00 0.62 0.77 300 2.0%27.7 250 1.0% Paved areas & shallow paved swales 20 2.0 2.1 29.8 550 13.1 13.1 E2 2 28,058 765 38,458 67,281 1.54 42.7% 0.49 0.00 0.49 0.62 200 1.5%24.9 100 0.5% Paved areas & shallow paved swales 20 1.4 1.2 26.1 300 11.7 11.7 OS1 3 17,197 17,197 0.39 0.0% 0.15 0.00 0.15 0.19 50 25.0%4.9 Paved areas & shallow paved swales 20 0.0 0.0 4.9 50 10.3 5.0 TOTAL SITE 105,871 11,473 19,624 11,275 0 0 130,561 0 278,803 6.40 49.6% 0.56 0.00 0.56 0.60 Basin Name Design Point Time of Conc (tc) C2 C5 C10 C100 2 5 10 100 ATotal (sf)ATotal (ac)Q2 Q5 Q10 Q100 E1 1 13.1 0.62 0.00 0.62 0.77 1.97 0.00 3.38 6.90 194,325 4.46 5.42 0.00 9.28 23.68 E2 2 11.7 0.49 0.00 0.49 0.62 2.07 0.00 3.54 7.24 67,281 1.54 1.58 0.00 2.69 6.89 OS1 3 5.0 0.15 0.00 0.15 0.19 2.85 0.00 4.87 9.95 17,197 0.39 0.17 0.00 0.29 0.74 0 0 0 0.00 TOTAL SITE 278,803 6.40 7.17 0.00 12.26 31.30 Initial Overland Time (ti)Travel Time (tt) tt=Length/(Velocity x 60) tc Urbanized Check ON Runoff Coeff's Rainfall Intensities (in/hr)Area Flow Rates (cfs) Runoff Coeff's JVA Civil Rational Calculations1 (version 2)1 Historic Page 1 of 1 JVA Incorporated Job Name: Fort Collins CNG I% C2 C5 C10 C100 1319 Spruce Street Job Number: 3256c Streets Paved 100% 0.95 0.00 0.95 1.00 Boulder, CO 80302 Date: 12/20/22 Concrete Drives/Walks 90% 0.95 0.00 0.95 1.00 Ph: (303) 444 1951 By: CDH Roof 90% 0.95 0.00 0.95 1.00 Gravel 40% 0.50 0.00 0.50 0.63 Landscaping (B soil) 0% 0.15 0.00 0.15 0.19 Fort Collins CNG Landscaping (C/D soil) 0% 0.25 0.00 0.25 0.31 Composite Runoff Coefficient Calculations Playground 10% 0.11 0.00 0.11 0.14 Location: Fort_Collins Artificial Turf 25% 0.20 0.00 0.20 0.25 Minor Design Storm: 2 Major Design Storm: 100 Soil Type: B Basin Design Data I (%) = 100% 90% 90% 40% 10% 25% 0% 0%I (%) Basin Name Design Point Apaved streets (sf) Adrives/c onc (sf) Aroof (sf) Agravel (sf) Aplygnd (sf) Aart. turf (sf) Alscape (B soil) (sf) Alscape (C/D soil) (sf) ATotal (sf) ATotal (ac) Imp (%)C2 C5 C10 C100 P1 1 75,440 10,708 21,998 11,274 74,905 194,325 4.46 56.3% 0.62 0.00 0.62 0.77 P2 2 32,084 5,629 2,316 757 26,495 67,281 1.54 58.8% 0.63 0.00 0.63 0.79 OS1 3 17,197 17,197 0.39 0.0% 0.15 0.00 0.15 0.19 0 0.00 Runoff Coeff's JVA Civil Rational Calculations1 (version 2)1 Developed C Page 1 of 1 JVA Incorporated Job Name: Fort Collins CNG 1319 Spruce Street Job Number: 3256c Boulder, CO 80302 Date: 12/20/22 Ph: (303) 444 1951 By: CDH Fort Collins CNG Time of Concentration Calculations Location: Fort_Collins Minor Design Storm: 2 Major Design Storm: 100 Soil Type: B Sub-Basin Data tc Comp tc Final Basin Name Design Point ATotal (ac)C5 Upper most Length (ft) Slope (%) ti (min) Length (ft)Slope (%) Type of Land Surface Cv Velocity (fps) tt (min) Time of Conc ti + tt = tc Total Length (ft) tc=(L/180)+ 10 (min) Min tc P1 1 4.46 0.00 200 2.0%22.6 450 1.0% Paved areas & shallow paved swales 20 2.0 3.8 26.4 650 13.6 13.6 P2 2 1.54 0.00 150 1.5%21.6 300 0.5% Paved areas & shallow paved swales 20 1.4 3.5 25.1 450 12.5 12.5 OS1 3 0.39 0.00 50 20.0%5.3 Paved areas & shallow paved swales 20 0.0 0.0 5.3 50 10.3 5.3 Initial Overland Time (ti)Travel Time (tt) tt=Length/(Velocity x 60) tc Urbanized Check ON JVA Civil Rational Calculations1 (version 2)1 Developed Tc Page 1 of 1 JVA Incorporated Job Name: Fort Collins CNG 1319 Spruce Street Job Number: 3256c Boulder, CO 80302 Date: 12/20/22 Ph: (303) 444 1951 By: CDH Fort Collins CNG Developed Storm Runoff Calculations Design Storm : 100 Year Point Hour Rainfall (P1) : 2.86 Basin Name Design Point Area (ac) Runoff Coeff tc (min) C*A (ac) I (in/hr) Q (cfs) Total tc (min) SC*A (ac) I (in/hr) Q (cfs) Inlet Type Q intercepted Q carryover Q bypass Pipe Size (in) or equivalent Pipe Material Slope (%) Pipe Flow (cfs) Max Pipe Capacity (cfs) Length (ft) Velocity (fps) tt (min)Total Time (min) NotesP1 1 4.46 0.77 13.60 3.43 6.79 23.32 13.60 3.43 6.79 23.32 P2 2 1.54 0.79 12.50 1.22 7.04 8.56 12.50 1.22 7.04 8.59 OS1 3 0.39 0.19 5.30 0.07 9.76 0.72 5.30 0.07 9.76 0.68 Direct Runoff Total Runoff Inlets Pipe Pipe/Swale Travel Time JVA Civil Rational Calculations1 (version 2)1 Q100 Page 1 of 1 JVA Incorporated Job Name: Fort Collins CNG 1319 Spruce Street Job Number: 3256c Boulder, CO 80302 Date: 12/20/22 Ph: (303) 444 1951 By: CDH Fort Collins CNG Developed Storm Runoff Calculations Design Storm : 2 Year Point Hour Rainfall (P1) : 0.82 Basin Name Design Point Area (ac) Runoff Coeff tc (min) C*A (ac) I (in/hr) Q (cfs) Total tc (min) SC*A (ac) I (in/hr) Q (cfs) Inlet Type Q intercepted Q carryover Q bypass Pipe Size (in) or equivalent Pipe Material Slope (%) Pipe Flow (cfs) Max Pipe Capacity (cfs) Length (ft) Velocity (fps) tt (min)Total Time (min) NotesP1 1 4.46 0.62 13.60 2.75 1.94 5.34 13.60 2.75 1.94 5.34 P2 2 1.54 0.63 12.50 0.97 2.02 1.96 12.50 0.97 2.02 1.95 OS1 3 0.39 0.15 5.30 0.06 2.80 0.17 5.30 0.06 2.80 0.17 Direct Runoff Total Runoff Inlets Pipe Pipe/Swale Travel Time JVA Civil Rational Calculations1 (version 2)1 Q Minor Page 1 of 1 Project: Basin ID: Must enter an equal number of stage and area values! Depth Increment = ft Watershed Information Top of Micropool -- 0.00 -- -- -- 888 0.020 Selected BMP Type =EDB -- 0.10 -- -- -- 888 0.020 Watershed Area = 1.54 acres -- 0.50 -- -- -- 1,404 0.032 Watershed Length = 300 ft -- 1.00 -- -- -- 1,920 0.044 Watershed Length to Centroid = 125 ft -- 1.43 -- -- -- Watershed Slope = 0.020 ft/ft -- 1.88 -- -- -- Watershed Imperviousness = 51.10% percent -- 2.33 -- -- -- Percentage Hydrologic Soil Group A = 0.0% percent -- 2.78 -- -- -- Percentage Hydrologic Soil Group B = 100.0% percent -- 3.23 -- -- -- Percentage Hydrologic Soil Groups C/D = 0.0% percent -- 3.68 -- -- -- Target WQCV Drain Time = 40.0 hours -- 4.13 -- -- -- Location for 1-hr Rainfall Depths = User Input -- 4.58 -- -- -- -- 5.03 -- -- -- -- 5.48 -- -- -- Optional User Overrides -- 5.93 -- -- -- Water Quality Capture Volume (WQCV) = 0.027 acre-feet acre-feet -- 6.38 -- -- -- Excess Urban Runoff Volume (EURV) = 0.084 acre-feet acre-feet -- 6.83 -- -- -- 2-yr Runoff Volume (P1 = 0.82 in.) = 0.044 acre-feet 0.82 inches -- 7.28 -- -- -- 5-yr Runoff Volume (P1 = 1.14 in.) = 0.068 acre-feet 1.14 inches -- 7.73 -- -- -- 10-yr Runoff Volume (P1 = 1.4 in.) = 0.094 acre-feet 1.40 inches -- 8.18 -- -- -- 25-yr Runoff Volume (P1 = 1.69 in.) = 0.134 acre-feet inches -- 8.63 -- -- -- 50-yr Runoff Volume (P1 = 1.99 in.) = 0.169 acre-feet inches -- -- -- -- 100-yr Runoff Volume (P1 = 2.86 in.) = 0.280 acre-feet 2.86 inches -- -- -- -- 500-yr Runoff Volume (P1 = 3.14 in.) = 0.316 acre-feet inches -- -- -- -- Approximate 2-yr Detention Volume = 0.044 acre-feet -- -- -- -- Approximate 5-yr Detention Volume = 0.066 acre-feet -- -- -- -- Approximate 10-yr Detention Volume = 0.092 acre-feet -- -- -- -- Approximate 25-yr Detention Volume = 0.106 acre-feet -- -- -- -- Approximate 50-yr Detention Volume = 0.116 acre-feet -- -- -- -- Approximate 100-yr Detention Volume = 0.166 acre-feet -- -- -- -- -- -- -- -- Define Zones and Basin Geometry -- -- -- -- Select Zone 1 Storage Volume (Required) = acre-feet -- -- -- -- Select Zone 2 Storage Volume (Optional) = acre-feet -- -- -- -- Select Zone 3 Storage Volume (Optional) = acre-feet -- -- -- -- Total Detention Basin Volume = acre-feet -- -- -- -- Initial Surcharge Volume (ISV) = user ft 3 -- -- -- -- Initial Surcharge Depth (ISD) = user ft -- -- -- -- Total Available Detention Depth (Htotal) =user ft -- -- -- -- Depth of Trickle Channel (HTC) =user ft -- -- -- -- Slope of Trickle Channel (STC) =user ft/ft -- -- -- -- Slopes of Main Basin Sides (Smain) =user H:V -- -- -- -- Basin Length-to-Width Ratio (RL/W) =user -- -- -- -- -- -- -- -- Initial Surcharge Area (AISV) =user ft 2 -- -- -- -- Surcharge Volume Length (LISV) =user ft -- -- -- -- Surcharge Volume Width (WISV) =user ft -- -- -- -- Depth of Basin Floor (HFLOOR) =user ft -- -- -- -- Length of Basin Floor (LFLOOR) =user ft -- -- -- -- Width of Basin Floor (WFLOOR) =user ft -- -- -- -- Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- -- Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- -- Depth of Main Basin (HMAIN) =user ft -- -- -- -- Length of Main Basin (LMAIN) =user ft -- -- -- -- Width of Main Basin (WMAIN) =user ft -- -- -- -- Area of Main Basin (AMAIN) =user ft 2 -- -- -- -- Volume of Main Basin (VMAIN) =user ft 3 -- -- -- -- Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- After providing required inputs above including 1-hour rainfall depths, click 'Run CUHP' to generate runoff hydrographs using the embedded Colorado Urban Hydrograph Procedure. Volume (ft 3) Volume (ac-ft) Area (acre) DETENTION BASIN STAGE-STORAGE TABLE BUILDER Optional Override Area (ft 2) Length (ft) Optional Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft 2) Width (ft) Fort Collins CNG Basin P2 Proposed MHFD-Detention, Version 4.04 (February 2021) Example Zone Configuration (Retention Pond) 3256c - MHFD-Detention_v4 04 RG Proposed, Basin 1/31/2023, 12:36 PM Project: Basin ID: Must enter an equal number of stage and area values! Depth Increment = ft Watershed Information Top of Micropool -- 0.00 -- -- -- 888 0.020 Selected BMP Type =EDB -- 0.10 -- -- -- 888 0.020 Watershed Area = 1.54 acres -- 0.50 -- -- -- 1,404 0.032 Watershed Length = 300 ft -- 1.00 -- -- -- 1,920 0.044 Watershed Length to Centroid = 125 ft -- 1.43 -- -- -- Watershed Slope = 0.020 ft/ft -- 1.88 -- -- -- Watershed Imperviousness = 49.60% percent -- 2.33 -- -- -- Percentage Hydrologic Soil Group A = 0.0% percent -- 2.78 -- -- -- Percentage Hydrologic Soil Group B = 100.0% percent -- 3.23 -- -- -- Percentage Hydrologic Soil Groups C/D = 0.0% percent -- 3.68 -- -- -- Target WQCV Drain Time = 40.0 hours -- 4.13 -- -- -- Location for 1-hr Rainfall Depths = User Input -- 4.58 -- -- -- -- 5.03 -- -- -- -- 5.48 -- -- -- Optional User Overrides -- 5.93 -- -- -- Water Quality Capture Volume (WQCV) = 0.026 acre-feet acre-feet -- 6.38 -- -- -- Excess Urban Runoff Volume (EURV) = 0.082 acre-feet acre-feet -- 6.83 -- -- -- 2-yr Runoff Volume (P1 = 0.82 in.) = 0.043 acre-feet 0.82 inches -- 7.28 -- -- -- 5-yr Runoff Volume (P1 = 1.14 in.) = 0.066 acre-feet 1.14 inches -- 7.73 -- -- -- 10-yr Runoff Volume (P1 = 1.4 in.) = 0.092 acre-feet 1.40 inches -- 8.18 -- -- -- 25-yr Runoff Volume (P1 = 1.69 in.) = 0.132 acre-feet inches -- 8.63 -- -- -- 50-yr Runoff Volume (P1 = 1.99 in.) = 0.167 acre-feet inches -- -- -- -- 100-yr Runoff Volume (P1 = 2.86 in.) = 0.278 acre-feet 2.86 inches -- -- -- -- 500-yr Runoff Volume (P1 = 3.14 in.) = 0.313 acre-feet inches -- -- -- -- Approximate 2-yr Detention Volume = 0.042 acre-feet -- -- -- -- Approximate 5-yr Detention Volume = 0.064 acre-feet -- -- -- -- Approximate 10-yr Detention Volume = 0.090 acre-feet -- -- -- -- Approximate 25-yr Detention Volume = 0.104 acre-feet -- -- -- -- Approximate 50-yr Detention Volume = 0.113 acre-feet -- -- -- -- Approximate 100-yr Detention Volume = 0.163 acre-feet -- -- -- -- -- -- -- -- Define Zones and Basin Geometry -- -- -- -- Select Zone 1 Storage Volume (Required) = acre-feet -- -- -- -- Select Zone 2 Storage Volume (Optional) = acre-feet -- -- -- -- Select Zone 3 Storage Volume (Optional) = acre-feet -- -- -- -- Total Detention Basin Volume = acre-feet -- -- -- -- Initial Surcharge Volume (ISV) = user ft 3 -- -- -- -- Initial Surcharge Depth (ISD) = user ft -- -- -- -- Total Available Detention Depth (Htotal) =user ft -- -- -- -- Depth of Trickle Channel (HTC) =user ft -- -- -- -- Slope of Trickle Channel (STC) =user ft/ft -- -- -- -- Slopes of Main Basin Sides (Smain) =user H:V -- -- -- -- Basin Length-to-Width Ratio (RL/W) =user -- -- -- -- -- -- -- -- Initial Surcharge Area (AISV) =user ft 2 -- -- -- -- Surcharge Volume Length (LISV) =user ft -- -- -- -- Surcharge Volume Width (WISV) =user ft -- -- -- -- Depth of Basin Floor (HFLOOR) =user ft -- -- -- -- Length of Basin Floor (LFLOOR) =user ft -- -- -- -- Width of Basin Floor (WFLOOR) =user ft -- -- -- -- Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- -- Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- -- Depth of Main Basin (HMAIN) =user ft -- -- -- -- Length of Main Basin (LMAIN) =user ft -- -- -- -- Width of Main Basin (WMAIN) =user ft -- -- -- -- Area of Main Basin (AMAIN) =user ft 2 -- -- -- -- Volume of Main Basin (VMAIN) =user ft 3 -- -- -- -- Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- DETENTION BASIN STAGE-STORAGE TABLE BUILDER Optional Override Area (ft 2) Length (ft) Optional Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft 2) Width (ft) Fort Collins CNG Basin P2 Existing MHFD-Detention, Version 4.04 (February 2021) Volume (ft 3) Volume (ac-ft) Area (acre) After providing required inputs above including 1-hour rainfall depths, click 'Run CUHP' to generate runoff hydrographs using the embedded Colorado Urban Hydrograph Procedure. Example Zone Configuration (Retention Pond) 3256c - MHFD-Detention_v4 04 RG (version 1), Basin 1/31/2023, 12:38 PM JVA Incorporated Job Name: Fort Collins CNG 1319 Spruce Street Job Number: 3256c Boulder, CO 80302 Date: 1/31/23 Ph: (303) 444 1951 By: CDH Fort Collins CNG Forebay Design Calculations Total Disturbed Acres 1 acres Contributing Impervious Acres 1.56 acres Disturbed Acres Imperviousness 0.54 % Total 100-Year Undetained Flow Rate 8.59 CFS Water Quality Capture Volume 0.021 ac-ft 1.56-Impervious Acres Requires 2% WQCV Min Forebay Volume Minimum Forebay Volume = 3% * WQCV 0.0006 ac-ft 27.4 CF Volume of each Forebay (Two Provided)13.7 CF Dimensions of each Forebay 6" Deep 4.5' Long Area =28 SF 6.3' Wide 14.0 CF 14 CF > 13.7 CF 2% of Undetained 100-Year Peak 0.17 CFS Max Release Rate Per Forebay (Two)0.09 CFS Rectangular Notch sized per Flowmaster 0.8 in 1.5W Channel Flow Rate per Flowmaster 2.2 CFS 2.2 CFS > 0.86 CFS Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =58.8 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.588 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.19 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 26,495 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =410 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin =312 sq ft D) Actual Flat Surface Area AActual =877 sq ft E) Area at Design Depth (Top Surface Area)ATop =1826 sq ft F) Rain Garden Total Volume VT=1,352 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =5.0 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =410 cu ft iii) Orifice Diameter, 3/8" Minimum DO =3/8 in Design Procedure Form: Rain Garden (RG) Chris Holmes JVA December 20, 2022 Fort Collins CNG 835 Wood Street UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.07 (1), RG 12/20/2022, 2:08 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) Chris Holmes JVA December 20, 2022 Fort Collins CNG 835 Wood Street Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO UD-BMP_v3.07 (1), RG 12/20/2022, 2:08 PM