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Home My WebLink AboutENCLAVE AT REDWOOD - FDP220014 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT (2) Geotechnical Engineering and Materials Testing Geotechnical Engineering Report Enclave at Redwood Residential Development Redwood Street and Suniga Drive Fort Collins, Colorado Prepared for: DHI Communities, a D.R. Horton Company 9555 South Kingston Court Englewood, CO 80112 Prepared by: Cole Garner Geotechnical CGG Project No.: 21.22.034 August 11, 2021 Geotechnical Engineering and Materials Testing Cole Garner Geotechnical 1070 W. 124th Ave, Ste. 300 Westminster, CO 80234 303.996.2999 August 11, 2021 DHI Communities, a D.R. Horton Company 9555 S Kingston Court Englewood, Colorado 80112 Attn: Mr. Tyler Field Development Manager tfield@drhorton.com 805.223.1761 Re: Geotechnical Engineering Report Enclave at Redwood Residential Development NEC of Redwood Street and Suniga Drive Fort Collins, Colorado CGG Project No. 21.22.034 Cole Garner Geotechnical (CG Geotech) has completed a design-level geotechnical engineering investigation for the proposed residential development to be located in the northeast corner of the subject intersection in Fort Collins, Colorado. This geotechnical summary should be used in conjunction with the entire report for design and/or construction purposes. It should be recognized that specific details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled General Comments should be read for an understanding of the report limitations. • Subsurface Conditions: Subsurface conditions encountered at the site generally included fine to coarse sand with silt and gravel overlying claystone bedrock. Limited lean clay lenses that were about 3 to 7 feet thick were encountered just beneath the surface in Boring Nos. 4, 6, 7, and 9. Sedimentary claystone bedrock was encountered in nine of our ten borings at depths ranging from about 17 to 23 feet below existing site grades and extended to the full depth of exploration, where encountered. Groundwater was encountered in our borings during drilling at depths ranging from about 8 to 17 feet below existing site grades (typically from 8 to 11 feet). When checked about two weeks later, groundwater levels ranged from about 8 to 12 feet below existing site grades. Other specific information regarding the subsurface conditions is shown on the attached Boring Logs. • Shallow Groundwater and Construction Dewatering: As mentioned, stable groundwater levels were measured in our borings at depths ranging from about 8 to 12 feet below existing site grades (EL 4,945.5 to 4,951.5 feet). Groundwater elevations reported in this study are similar to those Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page ii Geotechnical Engineering and Materials Testing estimated to be present after underdrain installation on the adjacent Northfield Development by Highland Development Services and to those recorded by A.G. Wassenaar (AGW) in February of 2020, with the exception of AGW’s shallowest groundwater measurement of AGW Boring No. TB-2 near the northern edge of the property (which may be an anomaly). As presented in Table 1 groundwater is expected to be present at depths ranging from about 7.7 to 17 feet after grading. We do not believe that groundwater should not prohibit at-grade residential construction (slab-on-grade foundations), but could impact deeper underground utility trenches To help reduce the impacts of groundwater on the construction process, we recommend that installation of the sanitary sewer system (typically the deepest trench) begin at the lowest point of the system (tie-in to the existing system at Northfield). If possible, we recommend installation of an underdrain be considered below the sanitary sewer to relive the expected groundwater inflow. The Civil Engineer should coordinate with the City of Fort Collins to determine if the installation of an underdrain is feasible. If underdrains can be used at the site, we recommend that they be designed using the flow rate information presented in this report. • Soft Soil Stabilization: Where shallow groundwater conditions are encountered, some soft/loose soil conditions may be encountered. These relatively moist and potentially unstable soils will likely need to be mitigated as construction activity begins on the site. Depending on seasonal conditions and the depth of excavations, these soils will likely need to be improved to provide a stable base for new infrastructure, foundations, or earthen fill. Contractors should plan on the use of track-mounted and/or lightweight equipment to complete deeper excavations. To aid in stabilization, we recommend crushing some inert construction materials or rock and blending these materials into the soft/unstable soils. Typically, these materials should be crushed to sizes ranging from about 3 to 6 inches and kneaded/compacted into the soft soils in order to provide a stable base for construction. • Below-Grade Construction: The shallow groundwater at the site will limit or preclude basement construction and likely impact earthwork activities, depending on site grading and the depth of underground utilities. We understand that basement construction is not currently planned for the project; however, crawlspace construction may be included in design of the structures. If the buildings are to include below-grade spaces, such as basement or crawlspace construction, we recommend raising the site grades as high as possible in order to help alleviate this condition. We recommend that the interior floor of any basement or crawlspace bear a minimum of three feet above groundwater. If basement or crawlspace construction will be used, foundation drainage and/or dewatering systems will be required. • Foundations and Floor Slabs: Provided that subgrade preparation is properly performed, the site appears suitable for the intended development. Considering the size and type of construction planned and the subsurface conditions encountered in our test borings, we believe that spread footings or post- tensioned slab-on-grade foundations are suitable for the proposed residential structures. Provided any Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page iii Geotechnical Engineering and Materials Testing 8/11/21 unstable or otherwise unsuitable soil conditions are mitigated, footings and slabs-on-grade may bear directly on the on-site soil or newly compacted fill comprised of the on-site or similar soils. • Private Pavements: The on-site soils include sands and clays, however, pavement design is typically conducted based on the properties of the poorest quality subgrade soils. We have estimated a resilient modulus of 3,025 psi for the on-site clay soils. Even though the pavements for the project will be privately maintained, the City of Fort Collins requires they be designed in general accordance with their Standards. Based on assumed traffic frequencies, we recommend 4 inches of hot-mix asphalt (HMA) over 6 inches of aggregate base course (ABC) be used to pave the private drives associated with the project. Additional section alternatives are presented in the report. For any public roadway improvements, the City of Fort Collins will require submittal of a pavement thickness design report based on completion of additional geotechnical exploration and analyses after completion of site grading. • Surface Drainage: The amount of movement associated with foundations, floor slabs, pavements, etc. will be related to the wetting of underlying supporting soils. Therefore, it is imperative the recommendations outlined in the “Grading and Drainage” section of this report be followed to reduce potential movement. We appreciate being of service to you in the geotechnical engineering phase of this project and are prepared to assist you during the construction phases as well. Please do not hesitate to contact us if you have any questions concerning this report or any of our testing, inspection, design, and consulting services. Sincerely, Cole Garner Geotechnical Patrick Maloney, G.I.T. Andrew J. Garner, P.E. Project Manager/Geologist Senior Project Manager Copies to: Addressee (1 PDF copy) Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page iv Geotechnical Engineering and Materials Testing TABLE OF CONTENTS Page No. Letter of Transmittal .............................................................................................................................. ii INTRODUCTION ..................................................................................................................................... 1 PROJECT INFORMATION ....................................................................................................................... 2 SITE EXPLORATION PROCEDURES ........................................................................................................ 2 Field Exploration ............................................................................................................................. 2 Laboratory Testing .......................................................................................................................... 3 SITE CONDITIONS .................................................................................................................................. 3 SUBSURFACE CONDITIONS ................................................................................................................... 3 Geology ........................................................................................................................................... 3 Soil and Bedrock Conditions ........................................................................................................... 4 Field and Laboratory Test Results ................................................................................................... 4 Groundwater Conditions ................................................................................................................ 4 Hydraulic Conductivity Testing ....................................................................................................... 5 ENGINEERING RECOMMENDATIONS ................................................................................................... 6 Geotechnical Considerations .......................................................................................................... 6 Earthwork ....................................................................................................................................... 7 Site Preparation ........................................................................................................................ 8 Excavations and Trench Construction ...................................................................................... 8 Temporary Construction Dewatering ....................................................................................... 9 Fill Materials ........................................................................................................................... 11 Fill Placement and Compaction Requirements ...................................................................... 11 Foundation Design and Construction ........................................................................................... 12 Lateral Earth Pressures ................................................................................................................. 13 Seismic Considerations ................................................................................................................. 14 Below-Grade Construction ........................................................................................................... 15 Non-structural Interior Floor Slabs ............................................................................................... 15 Private Pavement Design and Construction ................................................................................. 17 Final Grading, Landscaping, and Surface Drainage ....................................................................... 21 Additional Design and Construction Considerations .................................................................... 22 Exterior Slabs .......................................................................................................................... 22 Underground Utilities ............................................................................................................. 22 Concrete Corrosion Protection ............................................................................................... 22 GENERAL COMMENTS ........................................................................................................................ 23 APPENDIX A: SITE VICINITY MAP, BORING LOCATION DIAGRAM, BORING LOGS, GROUNDWATER DEPTH CONTOUR DIAGRAM, GROUNDWATER ELEVATION CONTOUR DIAGRAM APPENDIX B: LABORATORY TEST RESULTS APPENDIX C: GENERAL NOTES, FOUNDATION DRAIN DETAIL FOR BELOW-GRADE SPACES APPENDIX D: HYDRAULIC CONDUCTIVITY TEST RESULTS, INILTRATION RATE TEST RESULTS, GROUNDWATER ANALYTICAL TESTING RESULTS Geotechnical Engineering and Materials Testing Cole Garner Geotechnical 1070 W. 124th Ave, Ste. 300 Westminster, CO 80234 303.996.2999 GEOTECHNICAL ENGINEERING REPORT ENCLAVE AT REDWOOD RESIDENTIAL DEVELOPMENT NEC OF REDWOOD STREET AND SUNIGA DRIVE FORT COLLINS, COLORADO CGG Project No. 21.22.034 August 11, 2021 INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed residential development to be constructed at the subject intersection in Fort Collins, Colorado. This study was performed in general accordance with our proposal number P20.22.289 - REVISED, dated January 19, 2021. The purpose of these services is to provide information and geotechnical engineering recommendations relative to: • Subsurface soil and bedrock conditions • Groundwater conditions • Site preparation and earthwork • Foundation design and construction • Lateral earth pressures • Floor slab design and construction • Below-grade construction • Private pavement thickness design and construction • Surface and subsurface drainage The recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, our experience with similar subsurface conditions and structures, and our understanding of the proposed project. The following documents were provided for our review during the preparation of this report: • Geotechnical Site Development Study – Old Town North – Fort Collins, Colorado prepared by A.G. Wassenaar, Inc. (AGW) (AGW Project No. 201023) dated February 25, 2020. • Final Drainage Report for Northfield prepared by Highland Development Services (Highland Project No. 18-1000-00) dated February 26, 2020. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 2 Geotechnical Engineering and Materials Testing PROJECT INFORMATION We understand that the project will include development approximately 25 acres of vacant property located northeast of the subject intersection in Fort Collins, Colorado. Development of the site will include mass site grading, underground utility installation, and the construction of paved private drives and fire lanes to support residential development. We understand that the project will include a construction of one and two story single-family homes and duplexes housing a total of about 230 for-lease units. As currently planned, the homes will be supported at-grade foundations; however, crawlspace construction may be included in design of the structures. Basements are not planned at the site. A leasing and amenity building will be located near the southwest corner of the development. Two stormwater detention ponds and a one-acre pocket park are planned. Based on our review of grading plans, we assume that earthen cut and fill on the order of about 3 feet may be required to bring the site to construction grades, however, due to the presence of relatively shallow groundwater, we believe that cut depths should be limited as much as possible. If our assumptions above are not accurate, or if you have additional useful information, please inform us as soon as possible. SITE EXPLORATION PROCEDURES The scope of the services performed for this project included a subsurface exploration program, laboratory testing, and engineering analysis. Field Exploration: Our scope of services for this current study included geotechnical exploration of the subsurface materials at ten (10) locations on the site. As part of the February 2020 study completed by AGW at this site, sixteen (16) borings were drilled. Borings were located as shown on the Boring Location Diagram included in Appendix A. Borings were advanced to a depth of about 25 feet below existing site grades with truck and all-terrain- vehicle-mounted drilling rigs utilizing 4-inch diameter, solid-stem auger. All of the borings were completed as a temporary monitoring wells by installing perforated and screened PVC pipe in order to keep the borings open and allow for flow-rate testing and sampling of groundwater for the purposes of dewatering design and permitting. Our field personnel recorded a lithologic log of each boring during the drilling operations. At selected intervals, samples of the subsurface materials were obtained by driving Modified California samplers. Penetration resistance measurements were obtained by driving the sample barrels into the subsurface materials with a 140-pound automatic hammer falling 30 inches. The penetration resistance value is a useful index to the consistency, relative density or hardness of the materials encountered. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 3 Geotechnical Engineering and Materials Testing Groundwater measurements were made in each boring at the time of site exploration and again approximately 12 days later. Slug testing was conducted in two wells at the time of follow-up groundwater measurements in order to determine hydraulic conductivity of the subsurface profile to be used in calculating potential flow rates for subsurface drainage systems. Laboratory Testing: Samples retrieved during the field exploration were returned to the laboratory for observation by the project geotechnical engineer and were classified in general accordance with the Unified Soil Classification System described in Appendix C. Bedrock was classified according to the General Notes for Rock Classification. At that time, an applicable laboratory-testing program was formulated to determine engineering properties of the subsurface materials. Following the completion of the laboratory testing, the field descriptions were confirmed or modified as necessary, and Boring Logs were prepared. These logs are presented in Appendix A. Laboratory test results are presented in Appendix B. These results were used for the geotechnical engineering analyses and the development of foundation and earthwork recommendations. Laboratory tests were performed in general accordance with the applicable local or other accepted standards. Selected soil and bedrock samples were tested for the following engineering properties: • Water content • Dry density • Swell/Consolidation • Grain size • Plasticity Index • Water-soluble sulfates SITE CONDITIONS The site consists of a vacant lot located in the northeast corner of Redwood Street and Suniga Drive in Fort Collins, Colorado. The lot is bound by Suniga Drive, the Lake Canal Ditch, and the Northfield development to the south and east, existing residential development to the north, and Redwood Street and existing residential development to the west. At the time of our field exploration, the ground surface was covered with a low growth of grass and weeds. The proposed area of construction was generally level with a total relief on the order of about 5 feet across the site. We assume the project area is at or near final grade or will require only minimal cuts and fills of up to about 3 feet to provide positive site drainage. SUBSURFACE CONDITIONS Geology: Surficial geologic conditions at the site, as mapped by the U.S. Geological Survey (USGS) (1Colton, 1978), consist of Post-Piney Creek Alluvium (Qpp) of Upper Holocene Age. These materials are described 1 Colton, R.B., 1978, Geologic Map of the Boulder - Fort Collins – Greeley Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Miscellaneous Investigations Map I-855-G. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 4 Geotechnical Engineering and Materials Testing as dark grey sandy to gravelly alluvium that underlies the floodplains of major streams (such as the Cache La Poudre in this area). The thickness is reported to be about 5 to 15 feet. Bedrock mapped in the area consists various members of the Pierre Shale Formation (Kpu, Kpm, Kprl) of Upper Cretaceous Age. This formation within this area has been reported to include shale, sandstone, and siltstone. The finer-grained (shale) units within the formation can contain montmorillonitic clays that produce low to very high swelling pressures when moisture content is elevated. The thickness of the various members in this area has been reported to be on the order of 60 to 2,800 feet. Mapping completed by the Colorado Geological Survey (2Hart, 1972) indicates the site is located in an area of "Low Swell Potential”. This category typically has low swell but the upper 6 to 12 inches may locally have moderate swell potential. The thickness of the surficial deposits is generally variable and bedrock with higher swell potential may locally be less than 10 ft below the ground surface. Due to the gently sloping nature of the site, other geologic hazards at the site are anticipated to be low. Seismic activity in the area is anticipated to be low, and the property should be relatively stable from a structural standpoint. With proper site grading around proposed structures, erosional problems at the site should be reduced. Soil and Bedrock Conditions: Subsurface conditions encountered at the site generally included fine to coarse sand with silt and gravel overlying claystone bedrock. Limited lean clay lenses that were about 3 to 7 feet thick were encountered just beneath the surface in Boring Nos. 4, 6, 7, and 9. Sedimentary claystone bedrock was encountered in nine of our ten borings at depths ranging from about 17 to 23 feet below existing site grades and extended to the full depth of exploration, where encountered. Other specific information regarding the subsurface conditions is shown on the attached Boring Logs. Field and Laboratory Test Results: Field test results indicate that the clay soils were generally stiff to hard in relative consistency while the granular soils were loose to very dense in relative density (typically dense to very dense). The bedrock ranged from medium hard to very hard in density (typically very hard) based on penetration testing results. Laboratory test results indicate that the clay soils and claystone bedrock exhibit moderate plasticity and select samples exhibited low to moderate expansive potential at existing moisture contents. Testing of select samples for water-soluble sulfates indicated concentrations ranging from 600 to 800 parts per million (ppm). Groundwater Conditions: Groundwater was encountered in our borings during drilling at depths ranging from about 8 to 17 feet below existing site grades (typically from 8 to 11 feet). When checked about two weeks later, groundwater levels ranged from about 8 to 12 feet below existing site grades. 2 Hart, Stephen S., 1972, Potentially Swelling Soil and Rock in the Front Range Urban Corridor, Colorado, Colorado Geological Survey, Sheet 1 of 4. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 5 Geotechnical Engineering and Materials Testing Groundwater observations are summarized below: Table 1: Groundwater Summary Boring No. Ground Surface Elevation (ft) Groundwater Depth (ft) Groundwater Elevation (ft) Approximate Cut/Fill (+/- ft) Approximate Groundwater Depth After Cut/Fill (ft) During Drilling (2/19-2/23) After Drilling (3/3) 1 4960.50 11.0 9.0 4951.50 -0.5 8.5 2 4958.00 8.0 8.7 4949.30 -1 7.7 3 4956.50 11.0 11.0 4945.50 -0.5 10.5 4 4959.00 11.0 8.0 4951.00 +1 9.0 5 4958.75 11.0 8.0 4950.75 +1.25 9.3 6 4957.50 14.0 8.0 4949.50 +1.5 9.5 7 4959.25 8.0 9.3 4949.95 +0.75 10.1 8 4958.25 17.0 11.0 4947.25 +1.25 12.8 9 4961.00 11.0 10.5 4950.50 0 10.5 10 4960.00 17.0 12.0 4948.00 +5 17.0 The above groundwater observations are only representative of the locations explored at the time(s) of our exploration(s). Seasonal fluctuations in groundwater elevation beyond those indicated above should be expected, therefore, the possibility of groundwater fluctuations should be considered when developing design and construction plans for the project. Based upon review of U.S. Geological Survey Maps (3Hillier, et al, 1983), regional groundwater beneath the project area is expected to be encountered in unconsolidated alluvial deposits at depths generally between 5 and 10 feet below the ground surface. Hydraulic Conductivity Testing: Hydraulic conductivity (permeability) testing was completed at the site in Monitoring Well/Boring Nos. 2 and 7. We utilized a submerged water-level data-logger to monitor the water level in the well before raising groundwater by inserting a 5 feet long slug, during the resulting return (drop) of water level to static level (falling head), and after removal of the 5 feet long slug and during the resulting rise in water level (rising head). The water level measurements were imported into AQTESOLV® software in order to determine the hydraulic conductivity of the subsurface profile for both the rising and falling head tests. Table 2 below summarizes permeability and flow rate testing performed at the site. 3 Hillier, Donald E.; Schneider, Paul A., Jr.; and Hutchinson, E. Carter, 1983, Depth to Water Table (1976-1977) in the Greater Denver Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Map I-855-I. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 6 Geotechnical Engineering and Materials Testing Table 2: Hydraulic Conductivity Determinations Test Type Hydraulic Conductivity Centimeters/sec Gallons/min./ft2 (GPM/ft2) Gallons/day/ft2 Rising Head – 2 0.001807 0.02661109 38.32 Falling Head – 2 2.292 33.7499784 4.86 x 104 Rising Head – 7 0.001027 0.01512499 21.78 Falling Head – 7 2.594 38.2013644 5.501 x 104 Falling Head Avg. 2.443 35.9756714 5.181 x 104 ENGINEERING RECOMMENDATIONS Geotechnical Considerations: Based on the information obtained from our subsurface exploration(s), laboratory testing of selected samples, and a cursory review of geologic conditions, it is our opinion that the site appears suitable for development of the proposed project. The primary geotechnical considerations at the site are the presence of shallow groundwater, the need for construction dewatering, and potentially soft/unstable subgrade soils • Shallow Groundwater and Construction Dewatering: As mentioned, stable groundwater levels were measured in our borings at depths ranging from about 8 to 12 feet below existing site grades (EL 4,945.5 to 4,951.5 feet). Groundwater elevations reported in this study are similar to those estimated to be present after underdrain installation on the adjacent Northfield Development by Highland Development Services and to those recorded by A.G. Wassenaar (AGW) in February of 2020, with the exception of AGW’s shallowest groundwater measurement of AGW Boring No. TB-2 near the northern edge of the property (which may be an anomaly). As presented in Table 1 groundwater is expected to be present at depths ranging from about 7.7 to 17 feet after grading. We do not believe that groundwater should not prohibit at-grade residential construction (slab-on-grade foundations), but could impact deeper underground utility trenches To help reduce the impacts of groundwater on the construction process, we recommend that installation of the sanitary sewer system (typically the deepest trench) begin at the lowest point of the system (tie-in to the existing system at Northfield). If possible, we recommend installation of an underdrain be considered below the sanitary sewer to relive the expected groundwater inflow. The Civil Engineer should coordinate with the City of Fort Collins to determine if the installation of an underdrain is feasible. If underdrains can be used at the site, we recommend that they be designed using the flow rate information presented in this report. • Soft Soil Stabilization: Where shallow groundwater conditions are encountered, some soft/loose soil conditions may be encountered. These relatively moist and potentially unstable soils will likely need to be mitigated as construction activity begins on the site. Depending on seasonal conditions and the depth of excavations, these soils will likely need to be improved to provide a stable base for new Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 7 Geotechnical Engineering and Materials Testing infrastructure, foundations, or earthen fill. Contractors should plan on the use of track-mounted and/or lightweight equipment to complete deeper excavations. To aid in stabilization, we recommend crushing some inert construction materials or rock and blending these materials into the soft/unstable soils. Typically, these materials should be crushed to sizes ranging from about 3 to 6 inches and kneaded/compacted into the soft soils in order to provide a stable base for construction. • Below-Grade Construction: The shallow groundwater at the site will limit or preclude basement construction and likely impact earthwork activities, depending on site grading and the depth of underground utilities. We understand that basement construction is not currently planned for the project; however, crawlspace construction may be included in design of the structures. If the buildings are to include below-grade spaces, such as basement or crawlspace construction, we recommend raising the site grades as high as possible in order to help alleviate this condition. We recommend that the interior floor of any basement or crawlspace bear a minimum of three feet above groundwater. If basement or crawlspace construction will be used, foundation drainage and/or dewatering systems will be required. • Foundations and Floor Slabs: Provided that subgrade preparation is properly performed, the site appears suitable for the intended development. Considering the size and type of construction planned and the subsurface conditions encountered in our test borings, we believe that spread footings or post- tensioned slab-on-grade foundations are suitable for the proposed residential structures. Provided any unstable or otherwise unsuitable soil conditions are mitigated, footings and slabs-on-grade may bear directly on the on-site soil or newly compacted fill comprised of the on-site or similar soils. • Private Pavements: The on-site soils include sands and clays, however, pavement design is typically conducted based on the properties of the poorest quality subgrade soils. We have estimated a resilient modulus of 3,025 psi for the on-site clay soils. Even though the pavements for the project will be privately maintained, the City of Fort Collins requires they be designed in general accordance with their Standards. Based on assumed traffic frequencies, we recommend 4 inches of hot-mix asphalt (HMA) over 6 inches of aggregate base course (ABC) be used to pave the private drives associated with the project. Additional section alternatives are presented in the report. For any public roadway improvements, the City of Fort Collins will require submittal of a pavement thickness design report based on completion of additional geotechnical exploration and analyses after completion of site grading. • Surface Drainage: The amount of movement associated with foundations, floor slabs, pavements, etc. will be related to the wetting of underlying supporting soils. Therefore, it is imperative the recommendations outlined in the “Grading and Drainage” section of this report be followed to reduce potential movement. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 8 Geotechnical Engineering and Materials Testing Earthwork: The following presents our initial recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills on the project based on typical construction methods. As the design plans are finalized, these recommendations should be refined accordingly. Earthwork on the project should be observed and evaluated by the Geotechnical Engineer. The evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project. • Site Preparation: Strip and remove existing vegetation, debris, and any other deleterious materials from the site. Stripped materials consisting of vegetation and organic materials should be wasted from the site or stockpiled for use in re-vegetation of non-structural/landscaping areas. The on-site soils are considered to be relatively stable based on the conditions at the time of our exploration, but soft/loose soil conditions may be encountered as excavations approach groundwater elevation. Subgrade stability may also be affected by precipitation, repetitive construction traffic, or other factors. Where unstable conditions, if any, are encountered or develop during construction, workability may be improved by scarifying and aeration during warmer periods. In some areas, removal and recompaction (or replacement with other on-site soils) may be suitable to build a stable base for placement of new fills. In areas where subgrade soils are very soft/yielding (if any), gravel augmentation (mechanically compacting/kneading crushed rock into the subgrade soils) may be cost-effective. In our experience, crushed rock or recycled concrete materials on the order of 3 to 6 inches in size would be effective in most situations. As an alternative, chemical treatment by blending fly ash, lime or Portland cement into the subgrade could also be considered. The actual mitigation methods used should be based on observation of exposed conditions by the geotechnical engineer. • Excavations and Trench Construction: It is anticipated that excavations for the proposed construction can be accomplished with conventional, heavy-duty earthmoving equipment. All excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards. The site soils predominantly consist of sands that are prone to caving, es[ecially as excavation approach groundwater elevation. In our opinion, the soils at the site predominantly classify as OSHA Type C. An excavation side slope configuration of 1-½ to 1 (horizontal to vertical) should be used for the overburden soils unless the contractor’s OSHA competent personnel allow for steeper side slopes. If excavations approach property lines, public right-of-way, or adjacent facilities the contractor should assess the potential need to shore the sides of excavations. The individual contractor(s) is responsible for designing and constructing stable and dry, temporary excavations, as required, maintaining stability of both the excavation sides and bottom. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 9 Geotechnical Engineering and Materials Testing The soils to be penetrated by the proposed excavations may vary significantly across the site. The contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions are encountered at the time of construction, the actual conditions should be evaluated to determine any excavation modifications necessary to maintain safe conditions. • Temporary Construction Dewatering: Deep underground utility trenches will likely be excavated below the groundwater table. To help reduce the impacts of groundwater on the construction process, we recommend that installation of the sanitary sewer system (typically the deepest trench) begin at the lowest point of the system (tie-in to the existing system at Northfield). If possible, we recommend installation of an underdrain be considered below the sanitary sewer. The Civil Engineer should coordinate with the City of Fort Collins and the adjacent developer to determine if the installation of an underdrain is feasible. If underdrains can be used at the site, we recommend that they be designed using the flow rate information in this report. For the purpose of developing temporary construction dewatering design parameters, engineering analysis was conducted using the wetted thickness of the overburden soils in an excavation (determined by depth of excavation below water table), such as a sanitary sewer trench/underdrain in a seasonal high-water condition, and the hydraulic conductivities for the overburden soil presented in Table 2 above using the equation: Q = kA where k = hydraulic conductivity in GPM/ft2 A = wetted hydraulic front, ft2 Total flow rate for temporary dewatering will therefore depend on seasonal groundwater conditions and the geometry of the excavation being dewatered as follows when using the average fastest hydraulic conductivity: Q = (35.9756714 GPM/ft2)(wetted excavation perimeter + floor area) (depth of excavation below groundwater) Although sanitary sewer plans were not available, we anticipate that the deepest utility excavations or other temporary excavations may be up to about 5 feet below groundwater elevation. Flow rates into excavations can be estimated using the shallowest of our estimated post-grading groundwater depths (approximately 7.7 feet below site grade: EL 4,949.30’). Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 10 Geotechnical Engineering and Materials Testing Due to the inherent variability of the overburden soil and seasonal groundwater fluctuations, we believe that it is prudent to include a scaling factor to design the temporary construction dewatering system components if considering design based on measured groundwater depths. Similar sensitivity would be realized with fluctuations in soil permeability. We recommend the application of a scaling factor of 1.5 be applied to the calculated flows. Typically, the pump rates should rapidly decrease with time as the aquifer is drawn down. The contractor will need to monitor the drawdown and adjust the number of wells, well points, or sumps within the excavation as required to attain the necessary drawdown. Temporary dewatering should continue until the trenches are backfilled above groundwater elevation. Should groundwater levels rise above our available measurements or excavation sizes increase from those assumed, additional flows from utility excavations should be anticipated. Therefore, we recommend additional monitoring of water levels monthly up to construction to further refine this design, as needed. At a minimum, temporary dewatering and stabilization of the base of deep excavations should be anticipated. Pumping from sumps may be utilized to control water within the excavations. Well points may be required for significant groundwater flow, or where excavations penetrate groundwater to a significant depth. Temporary construction dewatering discharge will need to be permitted with the Water Quality Control Division of the Colorado Department of Public Health and Environment according to the stipulations of the SUDP. Geochemical testing results of water samples obtained from Monitoring Well/Boring No. 7 to assist effluent discharge permitting are presented in Appendix C. Discharge monitoring will be required to maintain construction dewatering permits to discharge the collected water into City storm drainage systems or other surface waters (per applicable State, City, and/or County requirements). We would be pleased to discuss these services, upon request Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 11 Geotechnical Engineering and Materials Testing • Fill Materials: Clean on-site soils or approved imported materials may be used as fill material. Imported soils (if required) should conform to the following: Percent finer by weight Gradation (ASTM C136) 6” ................................................................................................................................... 100 3" .................................................................................................................................... 100 No. 4 Sieve ................................................................................................................ 30-100 No. 50 Sieve ................................................................................................................ 10-60 No. 200 Sieve ................................................................................................................ 5-20 • Liquid Limit .................................................................................................................. 35 • Plasticity Index .............................................................................................................. 6 • Maximum expansive potential (%)* .......................................................................... 0.5 *Measured on a sample compacted to approximately 95 percent of the ASTM D698 maximum dry density at about optimum water content. The sample is confined under a 500 psf surcharge and submerged. • Fill Placement and Compaction: Engineered fill for site development, grading, and below foundations and floor slabs should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. Fill soils should be placed and compacted according to the following criteria: Criteria Recommended values Lift Thickness 8 to 12 inches or less in loose thickness Moisture Content Range • Clayey soils: +1% to +4% above optimum moisture content • Non-plastic sand soils: -2% below to +3% above optimum • Pavement areas: Optimum to +2% above optimum Compaction Clayey soils: ASTM D698 standard Proctor dry density • 95% minimum Non-plastic sand soils: ASTM D1557 modified Proctor dry density • 95% minimum Earthwork contractors should use equipment and methods that ensure relatively uniform distribution of added moisture and adequate compaction throughout each lift. We recommend that fill placement and compaction beneath foundations be observed and tested by CGG on a nearly full-time basis, unless modified by the geotechnical engineer. At a minimum, fill soils placed for site grading, utility trench backfill, foundation backfill or sub- excavation fill, and pavements and PCC flatwork subgrade soils should be tested to confirm that Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 12 Geotechnical Engineering and Materials Testing earthwork is being performed according to our recommendations and project specifications. Subsequent lifts of fill should not be placed on previous lifts if the moisture content or dry density is determined to be less than specified. Fill should not be allowed to dry significantly prior to construction. Areas allowed to dry may require additional preparation prior to construction of roadways, flatwork, foundations, etc. Foundation Design and Construction: Based on the subsurface conditions encountered in our borings, we believe the soils at the site are suitable for support of the residential structures. Due to the presence of low expansive soils at the site, spread footing or post-tensioned slab-on-grade foundations are considered acceptable for support of structures on this site. However, as discussed above, where any loose soils or other unsuitable materials are present below shallow foundations, they should be removed and recompacted as directed by CGG. The design of shallow foundations such as spread footings, mat foundations or post-tensioned slabs (using criteria outlined by the Post-Tensioning Institute4) should be based on the following: SPREAD FOOTING, MAT, or POST-TENSIONED SLABS Criteria Design Values Bearing Soils Undisturbed soils or recompacted engineered fill approved by the Geotechnical Engineer Maximum net allowable bearing pressure1 2,500 psf Min. depth below grade, exterior wall footings2 36 inches Min. depth below grade, interior footings 12 inches Edge moisture variation distance, em • 8.3 feet Center (shrink) • 4.9 feet Edge (swell) Differential Soil Movement, ym • -0.70 inch Center (shrink) • +1.15 inch Edge (swell) Slab subgrade coefficient 2.00 for on-site clay soils Estimated total foundation movement3 1 inch Estimated differential foundation movement3 ½ to ¾-inch 1. The design bearing pressure above applies to dead loads plus one-half of design live load conditions. The design bearing pressure may be increased by 1/3 when considering total loads that include wind or seismic conditions. 2. Finished grade is the lowest adjacent grade for perimeter footings and floor level for interior footings. 3. Based on assumed structural loads. Footings should be proportioned to apply relative constant dead load pressure in order to reduce differential movement between adjacent footings. It should be noted that ym is the estimated vertical movement at the edges of a uniformly loaded slab. These are theoretical values that are used in the design of post-tensioned slabs-on-grade and do not represent the movements that would be expected from the actual loading conditions. The estimated 4 Post-Tensioning Institute, (2004, Third Edition), Design of Post-Tensioned Slabs-on-Ground Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 13 Geotechnical Engineering and Materials Testing values of total and differential movement outlined above are considered the applicable to overall movement or “tilting” of the structures. As previously discussed, the use of either conventionally- reinforced or post-tensioned slabs-on-grade assumes that some potential movement is considered acceptable. Additional foundation movements could occur if water from any source infiltrates the foundation soils; therefore, proper drainage should be provided in the final design and during construction. Footings, foundations, and foundation walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in masonry walls is recommended. Foundation excavations should be observed by the geotechnical engineer during construction. If the soil or bedrock conditions encountered differ significantly from those presented in this report, supplemental recommendations may be required. Where spread footings are used, interior (non-structural) slab-on-grade floors should provide acceptable performance provided they are properly designed and constructed as discussed in subsequent sections of this report. Lateral Earth Pressures: Earth pressures will be influenced by structural design of the walls, conditions of wall restraint, methods of construction, wetting of backfill materials, and/or compaction and the strength of the materials being restrained. Loads that should be considered by the structural engineer on walls are shown below. Active earth pressure is commonly used for design of freestanding cantilever retaining walls and assumes wall movement. The "at-rest" condition assumes no wall rotation. Walls with unbalanced backfill levels on opposite sides (i.e. crawlspace, basement, or site retaining walls) should be designed for earth pressures at least equal to those indicated in the following table. The recommended design lateral earth pressures do not include a factor of safety and do not provide for possible hydrostatic pressure on the walls. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 14 Geotechnical Engineering and Materials Testing EARTH PRESSURE COEFFICIENTS Earth pressure conditions Coefficient for backfill type Equivalent fluid pressure, pcf Surcharge pressure P1, psf Earth pressure P2, psf Active (Ka) On-site clayey soils - 0.33 40 (0.33)S (40)H At-Rest (Ko) On-site clayey soils - 0.50 60 (0.50)S (60)H Passive (Kp) On-site clayey soils – 2.3 275 --- --- Conditions applicable to the above conditions include: • for active earth pressure, wall must rotate about base, with top lateral movements 0.01 Z to 0.02 Z, where Z is wall height • for passive earth pressure, wall must move horizontally to mobilize resistance • uniform surcharge, where S is surcharge pressure • in-situ soil backfill weight a maximum of 120 pcf • horizontal backfill, compacted to at least 95 percent of standard Proctor maximum dry density • loading from heavy compaction equipment not included • no groundwater acting on wall • no safety factor included • ignore passive pressure in frost zone Backfill placed against structures may consist of the on-site soils processed to a soil-like consistency with maximum particle sizes on the order of 4 to 6 inches. To calculate the resistance to sliding, a value of 0.35 may be used as the coefficient of friction between the footing and the underlying soil. If the project contains any walls which will retain unbalanced soil loads (i.e. basement, crawlspace, or site retaining walls), we recommend installation of a drainage system be installed at the base of the retained soil mass to control the water level behind the wall. If this is not possible, then combined hydrostatic and lateral earth pressures should be calculated for lean clay backfill using an equivalent fluid weighing 90 and 100 pcf for active and at-rest conditions, respectively. These pressures do not include the influence of surcharge, equipment or floor loading, which should be added. Heavy equipment should not operate within a distance closer than the exposed height of retaining walls to prevent lateral pressures more than those provided. Seismic Considerations: Based on the subsurface conditions encountered in the test holes drilled on the site, we estimate that a Site Class D is appropriate for the site according to the 2015 International Building Code (Section 1613.3.2 referencing Table 20.3-1 of ASCE 7, Chapter 20). This parameter was estimated based on extrapolation of data beyond the deepest depth explored, using methods allowed by the code. Actual shear wave velocity testing/analysis and/or exploration to 100 feet was not performed. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 15 Geotechnical Engineering and Materials Testing Below-grade Construction: As discussed, stable groundwater was encountered at depths ranging from about 8 to 12 feet below existing site grades, or predominantly about 7-½ to 10 feet below finished site grades. We understand that basement construction is not currently planned for the project; however, crawlspace construction may be included in design of the structures. If the buildings are to include below- grade spaces, such as crawlspace construction, we recommend raising the site grades as high as possible in order to help alleviate this condition. We recommend that the interior floor of any basement or crawlspace bear a minimum of three feet above groundwater. In addition, drainage and/or dewatering systems could be required, depending on finished grades. Final dewatering/drainage system design will need to account for final grading and architectural plans, however, in general terms, the drainage system should include a 4-inch diameter perforated pipe, installed in a trench at the base of each below-grade space. The drain trench should slope to the subdivision-wide underdrain system within the roadway, however, it is common to also install a sump pit within the structures to collect flows in case of a malfunction of the underdrain system. The perforated drain-pipe should be embedded in a zone of washed gravel to protect against the intrusion of fines. A typical construction detail for the interior foundation drainage system is included in Appendix C. In our experience, water that is discharged from the sump pit to the ground surface may pond within swales or behind curbs/sidewalks. Provided that the sump pit is higher than the underdrain connection, we believe that only minimal flows should collect in the sump pit. If water is discharged too close to the structures it can be “recycled” through the drain system frequently. Care should be used to properly direct discharged water to existing site improvements away from homes and other facilities. At a minimum, crawlspaces should be well ventilated and any exposed soil beneath the homes sealed with a moisture barrier. Non-structural Interior Floor Slabs : As discussed, non- to low expansive sand, clays, and bedrock were encountered on a majority of the site. In general, these soils are suitable for support for interior (non- structural) slab-on-grade floors with low risk of post-construction movement. Post-tensioned slab foundations are considered structural elements and should be designed and constructed as discussed above. Non-structural, interior floor slabs bearing on approved non- to low expansive native soils or on moisture- conditioned and compacted engineered fill could still experience movement when subjected to typical post-construction wetting, even with the recommended site preparation. However, we believe that movement would be limited to amounts that are generally tolerable for slab-on-grade construction in the region. Based on our analyses, provided mitigation of any large areas soft/unstable soils or dry, expansive soils are mitigated, we estimate potential slab-on-grade movement to be on the order of 1 to 2 inches. The movement estimate outlined above assumes that the other recommendations in this report are followed. Additional movement could occur should the subsurface soils become wetted to significant Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 16 Geotechnical Engineering and Materials Testing depths, which could result in potential excessive movement causing uneven floor slabs and severe cracking. This could be due to over watering of landscaping, poor drainage, improperly functioning drain systems, and/or broken utility lines. If slab-on-grade is utilized, the subgrade soils should be prepared as outlined in the “Earthwork” section of this report. For structural design of concrete slabs-on-grade, a modulus of subgrade reaction of 100 pounds per cubic inch (pci) may be used for floors supported on existing or compacted soils at the site. Additional floor slab design and construction recommendations are as follows: • Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement. • Control joints should be provided in slabs to control the location and extent of cracking. • A minimum 2-inch void space should be constructed below non-bearing partition walls placed on the floor slab. This typically involves suspending drywall 3 to 4 inches above the slab and utilizing a “bottom plate” in the framing to which baseboards can be connected (no connection from baseboards to drywall). Corner beads and other elements must also be isolated from the slab. • Doorjambs and frames within partition walls should be trimmed to allow for floor slab movement and avoid potential distortion (we understand that about ½-inch is typical). • The thickness of the partition void and gap at the base of door frames should be checked periodically and adjusted as needed to maintain a void space and avoid transferring slab movement to upper level framing. • Interior trench backfill placed beneath slabs should be compacted in accordance with recommended specifications outlined below. • The use of a vapor retarder should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder/barrier, the slab designer and slab contractor should refer to ACI 302 for procedures and cautions regarding the use and placement of a vapor retarder/barrier. • Floor slabs should not be constructed on frozen subgrade. • Other design and construction considerations, as outlined in Section 302.1R of the ACI Design Manual, are recommended. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 17 Geotechnical Engineering and Materials Testing Private Pavement Design and Construction: The design of private pavements for the project is based on the procedures outlined in the 2001 City of Fort Collins Urban Area Street Standards. The design methods are based on procedures outlined in the 1993 Guideline for Design of Pavement Structures by the American Association of State Highway and Transportation Officials (AASHTO), and the CDOT Pavement Design Manual by the Colorado Department of Transportation (CDOT). For any public roadway improvements, the City of Fort Collins will require submittal of a pavement thickness design report based on completion of additional geotechnical exploration and analyses after completion of site grading. • Subgrade Soil for Pavement Support: The majority of the soils on-site are sandy soils that are judged to provide fair to good support of pavements. However, the clayey soils encountered at the site are considered to offer poor pavement support. The referenced design methods are based on the subgrade soil support properties and anticipated traffic values. Based on the properties of the poorest quality subgrade soils, we have estimated an R-value of 5, corresponding to a resilient modulus of 3,025 psi using the CDOT correlation. A terminal serviceability index of 2.0 and a reliability index of 75 were applied in the design of the roadways. • Assumed Traffic: We assume that pavements associated with the project will include the fire lanes and main access drives along with surface parking for automobiles and light trucks. The following traffic designation criteria was used for determining pavement thicknesses using a design life of 20 years, as outlined in the City of Fort Collins Standards: City of Fort Collins Traffic Classification Equivalent Daily Load Application (EDLA) Equivalent (18-kip) Single Axle Load (ESAL) Local Residential – Two Lane 5 36,500 Local Residential – Single Lane 10 73,000 The owner should review these assumptions, and we should be contacted to confirm or modify these resulting pavement sections, if needed. • Private Pavement Sections: Recommended alternatives for flexible and rigid pavements are Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 18 Geotechnical Engineering and Materials Testing summarized for each traffic area as follows: Traffic Area Alternative* Preliminary Pavement Thickness (Inches) Asphalt Concrete Surface (AC) Aggregate Base Course (ABC) Portland Cement Concrete (PCC) Local Residential – Two Lane (EDLA = 5, ESAL = 36,500) A* 6 -- -- B* 4 6 -- C -- -- 5 Local Residential - Single Lane (EDLA = 10, ESAL = 73,000) A* 6.5 -- -- B* 5.5 6 -- C -- -- 6 * City of Fort Collins default minimum sections For areas subject to concentrated and repetitive loading conditions such as dumpster pads, truck delivery docks and ingress/egress aprons, we recommend using a Portland cement concrete pavement with a thickness of at least 7 inches. For dumpster pads, the concrete pavement area should be large enough to support the container and tipping axle of the refuse truck. Each alternative should be investigated with respect to current material availability and economic conditions. • Pavement Subgrade Preparation: Site grading is generally accomplished early in the construction phase. However, as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, drying/desiccation, or rainfall. As a result, the pavement subgrade may not be suitable for pavement construction and corrective action will be required. We recommend that any areas to receive fill be scarified, moisture conditioned, and recompacted to a depth of 12 inches. In addition, the upper 12 inches of pavement subgrade should be scarified, moisture conditioned, and recompacted immediately prior to final proofroll and paving. A proofroll of the subgrade soils should also be performed prior to paving and any soft/yielding areas remediated. Paving materials used at the site should meet current City of Fort Collins and CDOT specifications. • Temporary Unpaved Access Drives: In our opinion, the use of aggregate base course or crushed stone may be considered for use in constructing temporary access roads for construction traffic and/or all-weather fire truck access. In order to provide an all-weather surface, we recommend that the section include a minimum of 12 inches of aggregate base course (CDOT Class 5 or 6) or a minimum of 8 inches of 3-inch minus crushed aggregate (or recycled concrete). In our opinion, these sections would be suitable for the support of delivery and concrete trucks and occasional fire truck access (80,000 ponds maximum) for the Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 19 Geotechnical Engineering and Materials Testing anticipated duration of a typical project of this magnitude. The contractor should be responsible for monitoring the condition of unpaved drive lanes, including the repair and maintenance of the drive lanes throughout its use in order to provide the required access. We believe it is likely that these aggregate materials will be “contaminated” with soil and other constituents over the course of construction, therefore, the aggregate materials should not be considered part of the final pavement section unless otherwise evaluated and approved by the Geotechnical Engineer. • Pavement Materials: Materials and construction of pavements for the project should be in accordance with the requirements and specifications of the City of Fort Collins and CDOT. Aggregate base course (if used on the site) should consist of a blend of sand and gravel that meets strict specifications for quality and gradation. Use of materials meeting Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is recommended for base course. Aggregate base course should be placed in lifts not exceeding 6 inches and compacted to a minimum of 95 percent standard Proctor density (ASTM D698). Asphalt concrete should be composed of a mixture of aggregate, filler, and additives (if required) and approved bituminous material. The asphalt concrete should conform to approved mix designs stating the Hveem properties, optimum asphalt content, job mix formula and recommended mixing and placing temperatures. Aggregate used in asphalt concrete should meet particular gradations. Material meeting CDOT Grading S or SX specifications or equivalent is recommended for asphalt concrete. Mix designs should be submitted prior to construction to verify their adequacy. Asphalt material should be placed in maximum 3-inch lifts and compacted within a range of 92 to 96 percent of the theoretical maximum (Rice) density (ASTM D2041) or 95 percent Hveem density (ASTM D1560, D1561). Where rigid pavements are used, the concrete should be obtained from an approved mix design with the following minimum properties: • Modulus of Rupture @ 28 days ................................................................... 650 psi minimum • Strength Requirements ........................................................................................... ASTM C94 • Cement Type .................................................................................................. Type II Portland • Entrained Air Content ................................................................................................. 6 to 8% • Concrete Aggregate ........................................................... ASTM C33 and CDOT Section 703 Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes from the time the water is added to the mix. Other specifications outlined by CDOT should be followed. Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation. The location and extent of joints should be based upon the final pavement geometry. Sawed joints should be cut within 24 hours of concrete placement and should Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 20 Geotechnical Engineering and Materials Testing be a minimum of 25 percent of slab thickness plus 1/4 inch. All joints should be sealed to prevent entry of foreign material and doweled where necessary for load transfer. • Compliance: Recommendations for pavement design and construction presented depend upon compliance with recommended material specifications. To assess compliance, observation and testing should be performed under the observation of the geotechnical engineer. • Pavement Maintenance and Performance: Pavement design methods are intended to provide structural sections with adequate thickness over a particular subgrade such that wheel loads are reduced to a level the subgrade can support. The support characteristics of the subgrade for pavement design do not account for shrink/swell movements of an expansive clay subgrade such as is common in the region. Thus, the pavement may be adequate from a structural standpoint, yet still experience cracking and deformation due to shrink/swell relate movement of the subgrade. It is, therefore, important to minimize moisture changes in the subgrade to reduce shrink/swell movements. Future performance of pavements constructed on the clay soils at this site will be dependent upon several factors, including: • maintaining stable moisture content of the subgrade soils. • providing for a planned program of preventative maintenance. Pavements could crack in the future primarily because of expansion of the soils when subjected to an increase in moisture content to the subgrade. The cracking, while not desirable, does not necessarily constitute structural failure of the pavement. The performance of all pavements can be enhanced by minimizing excess moisture that can reach the subgrade soils. The following recommendations should be considered at minimum: • Site grading at a minimum 2 percent grade onto or away from pavements. • Water should not be allowed to pond behind curbs. • Compaction of any utility trenches for landscaped areas to the same criteria as the pavement subgrade. • Sealing all landscaped areas in or adjacent to pavements to minimize or prevent moisture migration to subgrade soils. • Placing compacted backfill against the exterior side of curb and gutter. • Placing curb, gutter and/or sidewalk directly on subgrade soils without the use of base course materials. • Placing shoulder or edge drains in pavement areas adjacent to water sources. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 21 Geotechnical Engineering and Materials Testing Preventative maintenance should be planned and provided for an ongoing pavement management program in order to enhance future pavement performance. Preventative maintenance activities are intended to slow the rate of pavement deterioration and to preserve the pavement investment. Preventative maintenance consists of both localized maintenance (e.g. crack sealing and patching and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Final Grading, Landscaping, and Surface Drainage: All grades must be adjusted to provide positive drainage away from structures during construction and maintained throughout the life of the proposed project. Water permitted to pond near or adjacent to the perimeter of the structures (either during or post-construction) can result in significantly higher soil movements than those discussed in this report. As a result, any estimations of potential movement described in this report cannot be relied upon if positive drainage is not obtained and maintained, and water is allowed to infiltrate the fill and/or subgrade. Infiltration of water into utility or foundation excavations must be prevented during construction. In accordance with the building code for non-expansive sites, exposed ground should be sloped at a minimum of 10 percent grade for at least 10 feet beyond the perimeter of the buildings, where possible. We understand that this may not be feasible in all unpaved areas due to ADA access requirements and other required design features. In these areas, exterior grades should be sloped as much as possible down to area drain systems, swales, and/or sidewalk chases to facilitate drainage. In all cases, we recommend that grades slope at least 5 percent away from the building in accordance with building codes. Downspouts should also be connected to storm sewers or area drain systems to help reduce wetting. If this is not possible, roof drain flows should be directed onto pavements or discharge a minimum of 5 feet away from the structure a through the use of splash blocks or downspout extensions. Backfill against foundations, exterior walls and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. After building construction and prior to project completion, we recommend that verification of final grading be performed to document that positive drainage, as described above, has been achieved. This is especially important in areas where heating and cooling units are placed in close proximity to the buildings. Planters located adjacent to the structure should preferably be self-contained (planter boxes, potted landscaping, etc.). Landscaped irrigation adjacent to foundations should be eliminated where possible or minimized to only limited drip irrigation. Sprinkler mains and spray heads should be located a minimum of 5 feet away from the buildings. We recommend the use of Xeric landscaping, requiring little or no irrigation, be used within 5 feet of foundations. If drip irrigation is required in this zone, systems Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 22 Geotechnical Engineering and Materials Testing should timed to provide only the amount of water needed to sustain growth. Irrigation systems should be frequently checked for proper performance and any breakages fixed as soon as possible. Additional Design and Construction Considerations: • Exterior Slabs: Exterior slabs-on-grade, exterior architectural features, and utilities founded on the on-site soils may experience some movement due to frost heave and potential volume change of backfill in utility trenches and around building pads. Potential movement could be reduced by: • minimizing moisture increases in the subgrade soils. • controlling moisture-density during placement of any backfill. • using designs which allow vertical movement between the exterior features and adjoining structural elements. • placing effective control joints on relatively close centers. • Underground Utilities: All underground piping within or near the proposed structure should be designed with flexible couplings, so minor deviations in alignment do not result in breakage or distress. Utility knockouts in foundation walls should be oversized to accommodate differential movements. It is strongly recommended that a representative of the geotechnical engineer provide full-time observation and compaction testing of trench backfill within building and pavement areas. • Concrete Corrosion Protection: Select soil/bedrock samples were tested for the presence of water- soluble sulfates, as outlined in the table below. Boring Depth (ft) Material Water-Soluble Sulfates (ppm) ACI Sulfate Exposure Class 7 2 Lean Clay with Sand 800 S1 9 2 Lean Clay with Sand 600 S1 The select samples, likely to be in contact with project concrete, were tested for the presence of water-soluble sulfates in order to determine corrosion characteristics and the appropriate concrete mixtures. Based on these results, project concrete should be designed for American Concrete Institute (ACI) Sulfate Exposure Class S1 in accordance with Chapter 19 of the ACI design manual, Building Code Requirements for Structural Concrete (ACI 318-14) as summarized below. Geotechnical Engineering Report Enclave at Redwood Residential Development – Fort Collins, CO CGG Project No. 21.22.034 Cole Garner Geotechnical Page 23 Geotechnical Engineering and Materials Testing ACI Sulfate Exposure Class Portland Cement Type (ASTM C150) Maximum Water/Cement Ratio Minimum Concrete Compressive Strength (psi) S1 II (or equivalent) 0.50 4,000 GENERAL COMMENTS CGG should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. CGG should also be retained to provide testing and observation during the excavation, grading, foundation, and construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include, either specifically or by implication, any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes are planned in the nature, design, or location of the project as outlined in this report, the conclusions and recommendations contained in this report shall not be considered valid unless CGG reviews the changes, and either verifies or modifies the conclusions of this report in writing. APPENDIX A SITE VICINITY MAP BORING LOCATION DIAGRAM BORING LOGS GROUNDWATER DEPTH CONTOUR DIAGRAM GROUNDWATER ELEVATION DIAGRAM APPROXIMATE PROJECT SITE LOCATION Cole Garner Geotechnical 1070 W. 124 th Ave., Suite 300 Westminster, CO 8023 4 (303) 996-2999 FIGURE 1 – SITE VICINITY MAP THE ENCLAVE AT REDWOOD FORT COLLINS, COLORADO CGG PROJECT NO. 21.22.034 APPROXIMATE BORING LOCATIONS Cole Garner Geotechnical 1070 W. 124 th Ave., Suite 300 Westminster, CO 8023 4 (303) 996-2999 AGW BORING LOCATIONS 1 1 2 3 4 6 8 7 5 FIGURE 2 - BORING LOCATION DIAGRAM THE ENCLAVE AT REDWOOD FORT COLLINS, COLORADO CGG PROJECT NO. 21.22.034 TB-1 TB-1 TB-2 TB-3 TB-4 TB-5 TB-6 TB-7 TB-8 TB-9 TB-10 TB-11 TB-12 TB-13 TB-14 TB-15 TB-16 10 9 50 / 5 50 / 7 50 / 9 50 / 3 50 / 6 131 1.6 5.7 6.8 10.6 100 100 100 0 100 FINE to COARSE SAND with SILT and GRAVEL, varies clayey, tan, light brown, white, dry to moist, dense to very dense Approximate bottom of borehole at 25.0 feet. 25 4935.5 CB CB CB CB CB SP-SM SP-SM SP-SM SP-SM SP-SM DRILLING METHOD Buggy Rig/Solid Stem Auger DATE STARTED 2/19/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/19/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4960 ft DURING DRILLING 11.00 ft / Elev 4949.50 ft AFTER DRILLING 9.00 ft / Elev 4951.50 ft - 3/3/21 GROUND SURFACE ELEV.4960.5 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 1 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 50 / 8 50 / 9 50 / 7 50 / 7 50 / 5 120 124 5.0 6.4 6.9 7.6 11.9 100 100 100 100 100 FINE to COARSE SAND with SILT and GRAVEL, varies to Silty Sand, tan, light brown, white, dry to moist, dense to very dense CLAYSTONE BEDROCK, varies sandy, bluish-grey, moist, very hard Approximate bottom of borehole at 25.0 feet. 22 25 4936.0 4933.0 CB CB CB CB CB SP-SM SM SP-SM SP-SM - DRILLING METHOD Buggy Rig/Solid Stem Auger DATE STARTED 2/19/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/19/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4957 ft DURING DRILLING 8.00 ft / Elev 4950.00 ft AFTER DRILLING 8.70 ft / Elev 4949.30 ft - 3/3/21 GROUND SURFACE ELEV.4958 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 2 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 50 / 6 50 / 7 50 / 5 50 / 4 50 / 4 2.2 9.3 4.4 16.4 16.7 100 100 100 100 100 FINE to COARSE SAND with SILT and GRAVEL, varies clayey, tan, light brown, white, dry to moist, very dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, moist, very hard Approximate bottom of borehole at 25.0 feet. 17 25 4939.5 4931.5 CB CB CB CB CB SP-SM SP-SM SP-SM - - DRILLING METHOD Buggy Rig/Solid Stem Auger DATE STARTED 2/19/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/19/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4956 ft DURING DRILLING 11.00 ft / Elev 4945.50 ft AFTER DRILLING 11.00 ft / Elev 4945.50 ft - 3/3/21 GROUND SURFACE ELEV.4956.5 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 3 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 29 / 12 50 / 7 50 / 6 50 / 4 50 / 4 104 8.1 7.1 5.8 11.4 19.3 100 100 100 100 100 SANDY LEAN CLAY, with gravel, brown, moist, very stiff FINE to COARSE SAND with SILT and GRAVEL, tan, light brown, white, dry to moist, very dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, moist, very hard Approximate bottom of borehole at 25.0 feet. 7 20 25 4952.0 4939.0 4934.0 CB CB CB CB CB CL SP-SM SP-SM SP-SM - DRILLING METHOD Buggy Rig/Solid Stem Auger DATE STARTED 2/19/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/19/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4960 ft DURING DRILLING 11.00 ft / Elev 4948.00 ft AFTER DRILLING 8.00 ft / Elev 4951.00 ft - 3/3/21 GROUND SURFACE ELEV.4959 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 4 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 11 / 12 29 / 12 50 / 11 50 / 4 50 / 3 126 133 4.3 5.7 4.5 8.6 13.1 100 100 100 100 100 FINE to COARSE SAND with SILT and GRAVEL, tan, light brown, white, moist, loose to very dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, moist, very hard Approximate bottom of borehole at 25.0 feet. 23 25 4935.8 4933.8 CB CB CB CB CB SP-SM SP-SM SP-SM SP-SM - DRILLING METHOD Buggy Rig/Solid Stem Auger DATE STARTED 2/19/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/19/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4460 ft DURING DRILLING 11.00 ft / Elev 4947.75 ft AFTER DRILLING 8.00 ft / Elev 4950.75 ft - 3/3/21 GROUND SURFACE ELEV.4958.75 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 5 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 16 / 12 35 / 12 50 / 7 50 / 9 49 / 12 50 / 2 112 110 115 -1.3/50014.1 1.2 5.7 6.6 19.1 15.9 100 100 100 100 100 100 SANDY LEAN CLAY, brown, tan, moist, stiff FINE to COARSE SAND with SILT and GRAVEL, tan, light brown, white, moist, medium dense to very dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, moist, medium hard to very hard Approximate bottom of borehole at 25.0 feet. 3 17 25 4954.5 4940.5 4932.5 CB CB CB CB CB CB CL SP-SM SP-SM SP-SM - - DRILLING METHOD CME-55 / Solid Stem Auger DATE STARTED 2/23/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/23/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4959 ft DURING DRILLING 14.00 ft / Elev 4943.50 ft AFTER DRILLING 8.00 ft / Elev 4949.50 ft GROUND SURFACE ELEV.4957.5 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 6 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 11 / 12 35 / 12 50 / 11 50 / 11 32 / 12 50 / 4 104 121 -0.5/50017.1 2.2 5.4 5.9 7.3 12.6 100 100 100 100 100 100 LEAN CLAY with SAND, with gravel, brown to dark brown, iron-stained, moist, stiff FINE to COARSE SAND with SILT and GRAVEL, tan, light brown, white, moist, medium dense to dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, moist, very hard Approximate bottom of borehole at 25.0 feet. 3 21 25 4956.3 4938.3 4934.3 CB CB CB CB CB CB CL SP-SM SP-SM SP-SM SP-SM - DRILLING METHOD CME-55 / Solid Stem Auger DATE STARTED 2/23/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/23/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4960 ft DURING DRILLING 8.00 ft / Elev 4951.25 ft AFTER DRILLING 9.30 ft / Elev 4949.95 ft - 3/3/21 GROUND SURFACE ELEV.4959.25 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 7 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:41 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 30 / 12 30 / 12 50 / 8 50 / 6 50 / 3 116 118 +3.1/1000 1.5 5.8 7.9 13.2 12.8 100 100 100 100 100 FINE to COARSE SAND with SILT and GRAVEL, tan, light brown, white, moist, medium dense to dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, moist, very hard Approximate bottom of borehole at 25.0 feet. 17 25 4941.3 4933.3 CB CB CB CB CB SP-SM SP-SM SP-SM - - DRILLING METHOD CME-55 / Solid Stem Auger DATE STARTED 2/23/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/23/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4960 ft DURING DRILLING 17.00 ft / Elev 4941.25 ft AFTER DRILLING 11.00 ft / Elev 4947.25 ft - 3/3/21 GROUND SURFACE ELEV.4958.25 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 8 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 45 / 12 15 / 12 48 / 12 35 / 12 50 / 10 50 / 2 113 +3.8/50010.1 0.8 6.2 6.9 9.8 4.3 100 100 100 100 100 100 LEAN CLAY with SAND, brown to light brown, tan, calcareous, dry to moist, hard FINE to COARSE SAND with SILT and GRAVEL, varies clayey, tan, light brown, white, dry to wet, medium dense to dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, dry, very hard Approximate bottom of borehole at 25.0 feet. 3 23 25 4958.0 4938.0 4936.0 CB CB CB CB CB CB CL SP-SM SP-SM SP-SM SP-SM - DRILLING METHOD CME-55 / Solid Stem Auger DATE STARTED 2/23/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/23/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4961 ft DURING DRILLING 11.00 ft / Elev 4950.00 ft AFTER DRILLING 10.50 ft / Elev 4950.50 ft - 3/3/21 GROUND SURFACE ELEV.4961 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 9 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 50 / 10 47 / 12 50 / 1 50 / 6 50 / 4 118 115 1.0 2.4 14.5 12.7 100 100 0 100 100 FINE to COARSE SAND with SILT and GRAVEL, tan, light brown, white, dry to moist, dense to very dense CLAYSTONE BEDROCK, varies sandy, grey, bluish-grey, brown, moist, very hard Approximate bottom of borehole at 25.0 feet. 18 25 4942.0 4935.0 CB CB CB CB CB SP-SM SP-SM SP-SM - - DRILLING METHOD CME-55 / Solid Stem Auger DATE STARTED 2/23/21 GROUND WATER LEVELS: SURFACE CONDITIONS Low growth of grass and weedsDRILLING CONTRACTOR Vine Laboratories COMPLETED 2/23/21 LOGGED BY JL CHECKED BY AG HAMMER TYPE Automatic PROPOSED ELEV.4965 ft DURING DRILLING 17.00 ft / Elev 4943.00 ft AFTER DRILLING 12.00 ft / Elev 4948.00 ft - 3/3/21 GROUND SURFACE ELEV.4960 ft GRAPHICLOGDEPTH(ft)0 5 10 15 20 25 PENETRATIONblows/inDRY UNIT WT.(pcf)SWELL-CONSOL/SURCHARGELOAD, %psfMOISTURECONTENT (%)RECOVERY %MATERIAL DESCRIPTION SAMPLE TYPEUSCS SYMBOLPAGE 1 OF 1 BORING NUMBER 10 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GEOTECH BH COLUMNS - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 APPROXIMATE BORING LOCATIONS Cole Garner Geotechnical 1070 W. 124 th Ave., Suite 300 Westminster, CO 8023 4 (303) 996-2999 AGW BORING LOCATIONS GROUNDWATER DEPTH CONTOUR (2 feet contour interval) GROUNDWATER SPOT DEPTH (feet) 1 1 2 3 4 6 8 7 5 FIGURE 3 – GROUNDWATER DEPTH CONTOUR DIAGRAM THE ENCLAVE AT REDWOOD FORT COLLINS, COLORADO CGG PROJECT NO. 21.22.034 TB-1 TB-1 TB-2 TB-3 TB-4 TB-5 TB-6 TB-7 TB-8 TB-9 TB-10 TB-11 TB-12 TB-13 TB-14 TB-15 TB-16 10 9 7 9 3.5 8 8 7 11 8 7.5 8 7.5 8 8.5 8.5 8 8 9 7 11 9.3 10 10.5 11.5 10 12 12 4 6 8 8 8 10 12 10 8 12 10 8 11 APPROXIMATE BORING LOCATIONS AGW BORING LOCATIONS Cole Garner Geotechnical 1070 W. 124 th Ave., Suite 300 Westminster, CO 8023 4 (303) 996-2999 APPROXIMATE GROUNDWATER ELEVATION (feet) 1 1 3 4 6 8 7 5 TB-1 10 9 4951.5 4949.3 4945.5 4951 4949.5 4950.75 4947.25 2 4949.9 5 4950.5 FIGURE 4 GROUNDWATER ELEVATION DIAGRAM THE ENCLAVE AT REDWOOD FORT COLLINS, COLORADO CGG PROJECT NO. 21.22.034 4948 XXXX = 4952 4950 4951 4949 4948 4947 4946 APPENDIX B LABORATORY TEST RESULTS 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 PI Cc NP 19 NP NP 19 NP 49 NP NP 43 CuLL PL 43.493.20 NP 30 NP NP 24 GRAIN SIZE DISTRIBUTION COBBLES GRAVEL 15.4 81.6 12.1 8.4 SAND GRAIN SIZE IN MILLIMETERS coarse fine Classification D100 D60 D30 D10 %Gravel 1.322 4.409 0.016 21.1 2 3 4 5 7 coarse SILT OR CLAYfinemedium 9.0 19.0 9.0 4.0 2.0 %Sand %Silt %Clay 0.432 0.765 1.195 0.101 73.0 47.1 53.9 50.0 BOREHOLE DEPTH BOREHOLE DEPTH 3 100 2 3 4 5 7 24 16 30 1 200610501/2 HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS 1403420 406 601.5 8 143/4 3/8 9.0 19.0 9.0 4.0 2.0PERCENT FINER BY WEIGHTSILTY SAND(SM) LEAN CLAY with SAND(CL) POORLY GRADED SAND with SILT and GRAVEL(SP-SM) LEAN CLAY with SAND(CL) 4.75 0.075 4.75 4.75 0.075 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GRAIN SIZE - GINT STD US LAB.GDT - 4/16/21 14:48 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 PI Cc 19 NP 49 NP CuLL PL 30 NP GRAIN SIZE DISTRIBUTION COBBLES GRAVEL 5.4 SAND GRAIN SIZE IN MILLIMETERS coarse fine Classification D100 D60 D30 D10 %Gravel 0.005 21.7 9 10 coarse SILT OR CLAYfinemedium 2.0 9.0 %Sand %Silt %Clay 0.945 0.212 52.4 60.0 BOREHOLE DEPTH BOREHOLE DEPTH 3 100 9 10 24 16 30 1 200610501/2 HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS 1403420 406 601.5 8 143/4 3/8 2.0 9.0PERCENT FINER BY WEIGHTLEAN CLAY with SAND(CL) 0.075 4.75 CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO GRAIN SIZE - GINT STD US LAB.GDT - 4/16/21 14:48 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.1 1 10 100CONSOLIDATION(-) % SWELL(+)APPLIED PRESSURE, ksf SWELL/CONSOLIDATION TEST 112 14 Date: 3/12/21Date: 3/12/21Note: Water Added to Sample at 500 psf. CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO BOREHOLE DEPTH 62.0 SANDY LEAN CLAY Classification MC%CONSOL STRAIN SINGLE - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.1 1 10 100CONSOLIDATION(-) % SWELL(+)APPLIED PRESSURE, ksf SWELL/CONSOLIDATION TEST 104 17 Date: 3/12/21Date: 3/12/21Note: Water Added to Sample at 500 psf. CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO BOREHOLE DEPTH 72.0LEAN CLAY with SAND(CL) Classification MC%CONSOL STRAIN SINGLE - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.1 1 10 100CONSOLIDATION(-) % SWELL(+)APPLIED PRESSURE, ksf SWELL/CONSOLIDATION TEST 116 13 Date: 3/12/21Date: 3/12/21Note: Water Added to Sample at 1000 psf. CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO BOREHOLE DEPTH 819.0 CLAYSTONE BEDROCK Classification MC%CONSOL STRAIN SINGLE - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.1 1 10 100CONSOLIDATION(-) % SWELL(+)APPLIED PRESSURE, ksf SWELL/CONSOLIDATION TEST 113 10 Date: 3/12/21Date: 3/12/21Note: Water Added to Sample at 500 psf. CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO BOREHOLE DEPTH 92.0LEAN CLAY with SAND(CL) Classification MC%CONSOL STRAIN SINGLE - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 1 4 FINE to COARSE SAND with SILT and GRAVEL 1.6 1 9 FINE to COARSE SAND with SILT and GRAVEL 5.7 130.5 1 14 FINE to COARSE SAND with SILT and GRAVEL 6.8 1 24 FINE to COARSE SAND with SILT and GRAVEL 10.6 2 4 FINE to COARSE SAND with SILT and GRAVEL 5.0 2 9 SILTY SAND(SM)6.4 120.4 15 NP NP NP 2 14 FINE to COARSE SAND with SILT and GRAVEL 6.9 2 19 FINE to COARSE SAND with SILT and GRAVEL 7.6 2 24 CLAYSTONE BEDROCK 11.9 123.6 3 4 FINE to COARSE SAND with SILT and GRAVEL 2.2 3 9 FINE to COARSE SAND with SILT and GRAVEL 9.3 3 14 FINE to COARSE SAND with SILT and GRAVEL 4.4 3 19 CLAYSTONE BEDROCK 16.4 82 49 19 30 3 24 CLAYSTONE BEDROCK 16.7 4 4 SANDY LEAN CLAY 8.1 4 9 FINE to COARSE SAND with SILT and GRAVEL 7.1 12 NP NP NP 4 14 FINE to COARSE SAND with SILT and GRAVEL 5.8 4 19 FINE to COARSE SAND with SILT and GRAVEL 11.4 4 24 CLAYSTONE BEDROCK 19.3 104.4 5 4 FINE to COARSE SAND with SILT and GRAVEL 4.3 8 NP NP NP 5 9 FINE to COARSE SAND with SILT and GRAVEL 5.7 125.8 5 14 FINE to COARSE SAND with SILT and GRAVEL 4.5 132.7 5 19 FINE to COARSE SAND with SILT and GRAVEL 8.6 5 24 CLAYSTONE BEDROCK 13.1 6 2 SANDY LEAN CLAY 14.1 112.2 -1.3/500 6 4 FINE to COARSE SAND with SILT and GRAVEL 1.2 6 9 FINE to COARSE SAND with SILT and GRAVEL 5.7 6 14 FINE to COARSE SAND with SILT and GRAVEL 6.6 6 19 CLAYSTONE BEDROCK 19.1 110.1 6 24 CLAYSTONE BEDROCK 15.9 115.0 Water Content (%) PAGE 1 OF 2 Liquid Limit Atterberg LimitsSwell (+) or Consolidation (-)/ Surcharge (%/psf) Dry Density (pcf) Passing #200 Sieve (%) Water Soluble Sulfates (ppm) SUMMARY OF LABORATORY RESULTS Soil Description Plastic Limit Plasticity Index Borehole Depth CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO LAB SUMMARY - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 7 2 LEAN CLAY with SAND(CL) 17.1 104.0 -0.5/500 800 71 43 19 24 7 4 FINE to COARSE SAND with SILT and GRAVEL 2.2 7 9 FINE to COARSE SAND with SILT and GRAVEL 5.4 7 14 FINE to COARSE SAND with SILT and GRAVEL 5.9 7 19 FINE to COARSE SAND with SILT and GRAVEL 7.3 7 24 CLAYSTONE BEDROCK 12.6 120.6 8 4 FINE to COARSE SAND with SILT and GRAVEL 1.5 8 9 FINE to COARSE SAND with SILT and GRAVEL 5.8 8 14 FINE to COARSE SAND with SILT and GRAVEL 7.9 8 19 CLAYSTONE BEDROCK 13.2 115.5 +3.1/1000 8 24 CLAYSTONE BEDROCK 12.8 117.9 9 2 LEAN CLAY with SAND(CL) 10.1 112.7 +3.8/500 600 82 49 19 30 9 4 FINE to COARSE SAND with SILT and GRAVEL 0.8 9 9 FINE to COARSE SAND with SILT and GRAVEL 6.2 9 14 FINE to COARSE SAND with SILT and GRAVEL 6.9 9 19 FINE to COARSE SAND with SILT and GRAVEL 9.8 9 24 CLAYSTONE BEDROCK 4.3 10 4 FINE to COARSE SAND with SILT and GRAVEL 1.0 10 9 FINE to COARSE SAND with SILT and GRAVEL 2.4 5 NP NP NP 10 19 CLAYSTONE BEDROCK 14.5 117.5 10 24 CLAYSTONE BEDROCK 12.7 115.0 Water Content (%) PAGE 2 OF 2 Liquid Limit Atterberg LimitsSwell (+) or Consolidation (-)/ Surcharge (%/psf) Dry Density (pcf) Passing #200 Sieve (%) Water Soluble Sulfates (ppm) SUMMARY OF LABORATORY RESULTS Soil Description Plastic Limit Plasticity Index Borehole Depth CLIENT DHI Communities, a D.R. Horton Company PROJECT NUMBER 21.22.034 PROJECT NAME Enclave at Redwood PROJECT LOCATION NEC of Redwood St & Suniga Dr - Fort Collins, CO LAB SUMMARY - GINT STD US LAB.GDT - 4/22/21 10:42 - Y:\GINT BACKUPS\MAIN TRANSFER 10.28\PROJECTS GEO 2021\21.22.034 ENCLAVE AT REDWOOD.GPJCole Garner Geotechnical1070 W 124th Ave Suite 300Westminster, CO 80234Telephone: 303-996-2999 APPENDIX C GENERAL NOTES FOUNDATION DRAIN DETAIL GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1!" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube – 2.5" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger CB: California Barrel - 1.92" I.D., 2.5" O.D., unless otherwise noted RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”. For 2.5” O.D. California Barrel samplers (CB) the penetration value is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer falling 30 inches, reported as “blows per inch,” and is not considered equivalent to the “Standard Penetration” or “N-value”. WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. FINE-GRAINED SOILS COARSE-GRAINED SOILS BEDROCK (CB) Blows/Ft. (SS) Blows/Ft. Consistency (CB) Blows/Ft. (SS) Blows/Ft. Relative Density (CB) Blows/Ft. (SS) Blows/Ft. Consistency < 3 0-2 Very Soft 0-5 < 3 Very Loose < 24 < 20 Weathered 3-5 3-4 Soft 6-14 4-9 Loose 24-35 20-29 Firm 6-10 5-8 Medium Stiff 15-46 10-29 Medium Dense 36-60 30-49 Medium Hard 11-18 9-15 Stiff 47-79 30-50 Dense 61-96 50-79 Hard 19-36 16-30 Very Stiff > 79 > 50 Very Dense > 96 > 79 Very Hard > 36 > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Terms of Other Constituents Percent of Dry Weight Major Component of Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Terms of Other Constituents Percent of Dry Weight Term Plasticity Index Trace With Modifiers < 5 5 – 12 > 12 Non-plastic Low Medium High 0 1-10 11-30 30+ UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF Clean Gravels Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF Fines classify as ML or MH GM Silty gravelF,G, H Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H Cu ! 6 and 1 " Cc " 3E SW Well graded sandI Clean Sands Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI Fines classify as ML or MH SM Silty sandG,H,I Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines More than 12% finesD Fines classify as CL or CH SC Clayey sandG,H,I PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Silts and Clays Liquid limit less than 50 Inorganic PI < 4 or plots below “A” lineJ ML SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,N Fine-Grained Soils 50% or more passes the No. 200 sieve Organic Liquid limit - not dried < 0.75 OL Organic siltK,L,M,O Inorganic PI plots on or above “A” line CH Fat clayK,L,M Silts and Clays Liquid limit 50 or more PI plots below “A” line MH Elastic siltK,L,M Liquid limit - oven dried Organic clayK,L,M,P Organic Liquid limit - not dried < 0.75 OH Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well graded gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well graded sand with silt, SW-SC well graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D60/D10 Cc = F If soil contains ! 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains ! 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ! 30% plus No. 200 predominantly sand, add “sandy” to group name. M If soil contains ! 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI ! 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. ROCK CLASSIFICATION (Based on ASTM C-294) Sedimentary Rocks Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be composed of particles or pre-existing rocks derived by mechanical weathering, evaporation or by chemical or organic origin. The sediments are usually indurated by cementation or compaction. Chert Very fine-grained siliceous rock composed of micro-crystalline or cyrptocrystalline quartz, chalcedony or opal. Chert is various colored, porous to dense, hard and has a conchoidal to splintery fracture. Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any rock containing clay. Soft massive and may contain carbonate minerals. Conglomerate Rock consisting of a considerable amount of rounded gravel, sand and cobbles with or without interstitial or cementing material. The cementing or interstitial material may be quartz, opal, calcite, dolomite, clay, iron oxides or other materials. Dolomite A fine-grained carbonate rock consisting of the mineral dolomite [CaMg(CO3)2]. May contain noncarbonate impurities such as quartz, chert, clay minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL). Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaCO3). May contain noncarbonate impurities such as quartz, chert, clay minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL). Sandstone Rock consisting of particles of sand with or without interstitial and cementing materials. The cementing or interstitial material may be quartz, opal, calcite, dolomite, clay, iron oxides or other material. Shale Fine-grained rock composed of or derived by erosion of silts and clays or any rock containing clay. Shale is hard, platy, of fissile may be gray, black, reddish or green and may contain some carbonate minerals (calcareous shale). Siltstone Fine grained rock composed of or derived by erosion of silts or rock containing silt. Siltstones consist predominantly of silt sized particles (0.0625 to 0.002 mm in diameter) and are intermediate rocks between claystones and sandstones and may contain carbonate minerals. LABORATORY TEST SIGNIFICANCE AND PURPOSE TEST SIGNIFICANCE PURPOSE California Bearing Ratio Used to evaluate the potential strength of subgrade soil, subbase, and base course material, including recycled materials for use in road and airfield pavements. Pavement Thickness Design Consolidation Used to develop an estimate of both the rate and amount of both differential and total settlement of a structure. Foundation Design Direct Shear Used to determine the consolidated drained shear strength of soil or rock. Bearing Capacity, Foundation Design, and Slope Stability Dry Density Used to determine the in-place density of natural, inorganic, fine-grained soils. Index Property Soil Behavior Expansion Used to measure the expansive potential of fine-grained soil and to provide a basis for swell potential classification. Foundation and Slab Design Gradation Used for the quantitative determination of the distribution of particle sizes in soil. Soil Classification Liquid & Plastic Limit, Plasticity Index Used as an integral part of engineering classification systems to characterize the fine-grained fraction of soils, and to specify the fine-grained fraction of construction materials. Soil Classification Permeability Used to determine the capacity of soil or rock to conduct a liquid or gas. Groundwater Flow Analysis pH Used to determine the degree of acidity or alkalinity of a soil. Corrosion Potential Resistivity Used to indicate the relative ability of a soil medium to carry electrical currents. Corrosion Potential R-Value Used to evaluate the potential strength of subgrade soil, subbase, and base course material, including recycled materials for use in road and airfield pavements. Pavement Thickness Design Soluble Sulfate Used to determine the quantitative amount of soluble sulfates within a soil mass. Corrosion Potential Unconfined Compression To obtain the approximate compressive strength of soils that possess sufficient cohesion to permit testing in the unconfined state. Bearing Capacity Analysis for Foundations Water Content Used to determine the quantitative amount of water in a soil mass. Index Property Soil Behavior REPORT TERMINOLOGY (Based on ASTM D653) Allowable Soil Bearing Capacity The recommended maximum contact stress developed at the interface of the foundation element and the supporting material. Alluvium Soil, the constituents of which have been transported in suspension by flowing water and subsequently deposited by sedimentation. Aggregate Base Course A layer of specified material placed on a subgrade or subbase usually beneath slabs or pavements. Backfill A specified material placed and compacted in a confined area. Bedrock A natural aggregate of mineral grains connected by strong and permanent cohesive forces. Usually requires drilling, wedging, blasting or other methods of extraordinary force for excavation. Bench A horizontal surface in a sloped deposit. Caisson (Drilled Pier or Shaft) A concrete foundation element cast in a circular excavation which may have an enlarged base. Sometimes referred to as a cast-in-place pier or drilled shaft. Coefficient of Friction A constant proportionality factor relating normal stress and the corresponding shear stress at which sliding starts between the two surfaces. Colluvium Soil, the constituents of which have been deposited chiefly by gravity such as at the foot of a slope or cliff. Compaction The densification of a soil by means of mechanical manipulation Concrete Slab-on- Grade A concrete surface layer cast directly upon a base, subbase or subgrade, and typically used as a floor system. Differential Movement Unequal settlement or heave between, or within foundation elements of structure. Earth Pressure The pressure exerted by soil on any boundary such as a foundation wall. ESAL Equivalent Single Axle Load, a criteria used to convert traffic to a uniform standard, (18,000 pound axle loads). Engineered Fill Specified material placed and compacted to specified density and/or moisture conditions under observations of a representative of a geotechnical engineer. Equivalent Fluid A hypothetical fluid having a unit weight such that it will produce a pressure against a lateral support presumed to be equivalent to that produced by the actual soil. This simplified approach is valid only when deformation conditions are such that the pressure increases linearly with depth and the wall friction is neglected. Existing Fill (or Man-Made Fill) Materials deposited throughout the action of man prior to exploration of the site. Existing Grade The ground surface at the time of field exploration. REPORT TERMINOLOGY (Based on ASTM D653) Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of moisture. Finished Grade The final grade created as a part of the project. Footing A portion of the foundation of a structure that transmits loads directly to the soil. Foundation The lower part of a structure that transmits the loads to the soil or bedrock. Frost Depth The depth at which the ground becomes frozen during the winter season. Grade Beam A foundation element or wall, typically constructed of reinforced concrete, used to span between other foundation elements such as drilled piers. Groundwater Subsurface water found in the zone of saturation of soils or within fractures in bedrock. Heave Upward movement. Lithologic The characteristics which describe the composition and texture of soil and rock by observation. Native Grade The naturally occurring ground surface. Native Soil Naturally occurring on-site soil, sometimes referred to as natural soil. Optimum Moisture Content The water content at which a soil can be compacted to a maximum dry unit weight by a given compactive effort. Perched Water Groundwater, usually of limited area maintained above a normal water elevation by the presence of an intervening relatively impervious continuous stratum. Scarify To mechanically loosen soil or break down existing soil structure. Settlement Downward movement. Skin Friction (Side Shear) The frictional resistance developed between soil and an element of the structure such as a drilled pier. Soil (Earth) Sediments or other unconsolidated accumulations of solid particles produced by the physical and chemical disintegration of rocks, and which may or may not contain organic matter. Strain The change in length per unit of length in a given direction. Stress The force per unit area acting within a soil mass. Strip To remove from present location. Subbase A layer of specified material in a pavement system between the subgrade and base course. Subgrade The soil prepared and compacted to support a structure, slab or pavement system. Cole Garner Geotechnical 1070"W.#124 th!Ave.,&Suite&300! Westminster,*CO*80234! (303)%996"2999! TYPICAL(INTERIOR( PERIMETER(DRAIN(DETAIL( FOOTING(FOUNDATION( NOT!TO!SCALE! 6. DRAINS SHALL BE INSTALLED IN WINDOW WELLS AND CONNECTED TO DISCHARGE INTO FOUNDATIOON DRAIN SYSTEM Cole Garner Geotechnical 1070"W.#124 th!Ave.,&Suite&300! Westminster,*CO*80234! (303)%996"2999! TYPICAL(EXTERIOR(( PERIMETER(DRAIN(DETAIL( FOOTING(FOUNDATION( NOT!TO!SCALE! 6. DRAINS SHALL BE INSTALLED IN WINDOW WELLS AND CONNECTED TO DISCHARGE INTO FOUNDATIOON DRAIN SYSTEM APPENDIX D HYDRAULIC CONDUCTIVITY TESTING RESULTS INILTRATION RATE TEST RESULTS GROUNDWATER ANALYTICAL TESTING RESULTS 0. 20. 40. 60. 80. 100. 0.01 0.1 1. Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 11:07:34 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 2 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 13.3 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-2) Initial Displacement: 0.5 ft Static Water Column Height: 11.3 ft Total Well Penetration Depth: 28.7 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.083 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 0.001807 cm/sec y0 = 0.1465 ft 0. 20. 40. 60. 80. 100. 0.01 0.1 1. Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 11:08:03 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 2 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 13.3 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-2) Initial Displacement: 0.5 ft Static Water Column Height: 11.3 ft Total Well Penetration Depth: 28.7 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.083 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 38.32 gal/day/ft2 y0 = 0.1465 ft 0. 40. 80. 120. 160. 200. 1.0E-4 0.001 0.01 0.1 Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 10:19:39 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 2 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 13.3 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-2) Initial Displacement: 0.2 ft Static Water Column Height: 11.3 ft Total Well Penetration Depth: 28.7 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.083 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 2.292 cm/sec y0 = 1. ft 0. 40. 80. 120. 160. 200. 1.0E-4 0.001 0.01 0.1 Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 10:03:42 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 2 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 13.3 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-2) Initial Displacement: 0.2 ft Static Water Column Height: 11.3 ft Total Well Penetration Depth: 28.7 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.083 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 4.86E+4 gal/day/ft2 y0 = 1. ft 0. 20. 40. 60. 80. 100. 1.0E-4 0.001 0.01 0.1 1. Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 13:42:54 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 7 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 11.75 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-7) Initial Displacement: 0.2 ft Static Water Column Height: 10.75 ft Total Well Penetration Depth: 19.25 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.25 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 0.001027 cm/sec y0 = 0.01752 ft 0. 20. 40. 60. 80. 100. 1.0E-4 0.001 0.01 0.1 1. Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 13:43:33 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 7 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 11.75 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-7) Initial Displacement: 0.2 ft Static Water Column Height: 10.75 ft Total Well Penetration Depth: 19.25 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.25 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 21.78 gal/day/ft2 y0 = 0.01752 ft 0. 16. 32. 48. 64. 80. 0.01 0.1 Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 13:34:04 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 7 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 11.75 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-7) Initial Displacement: 0.048 ft Static Water Column Height: 10.75 ft Total Well Penetration Depth: 19.25 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.25 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 2.594 cm/sec y0 = 1. ft 0. 16. 32. 48. 64. 80. 0.01 0.1 Time (sec)Displacement (ft)ENCLAVE AT REDWOOD Data Set: Date: 03/16/21 Time: 13:34:42 PROJECT INFORMATION Company: Cole Garner Geotech Client: D.R. Horton Project: 21.22.034 Location: Fort Collins, CO Test Well: 7 Test Date: 3/3/121 AQUIFER DATA Saturated Thickness: 11.75 ft Anisotropy Ratio (Kz/Kr): 1. WELL DATA (MW-7) Initial Displacement: 0.048 ft Static Water Column Height: 10.75 ft Total Well Penetration Depth: 19.25 ft Screen Length: 15. ft Casing Radius: 0.083 ft Well Radius: 0.25 ft SOLUTION Aquifer Model: Unconfined Solution Method: Bouwer-Rice K = 5.501E+4 gal/day/ft2 y0 = 1. ft 3/3/2021 Hole diameter (in):2 Approx. Test Depth (in):60 Infiltration Rate During Interval (in/hr) 1.00 1.50 1.25 1.25 0.75 1.00 Average Infiltration Rate 1.15 Cased borehole infiltration test method performed at a depth of approximately 5 feet below existing site grade. Test performed in the fine to coarse sand with silt and gravel stratum. (303) 996-2999 Date: Field Infiltration Rate Test No. 3 Project Name: Cole Garner Project No.: Interval End Time Length of Interval (hh:mm) 3:10 4:25 4:10 Interval Start Time Eng./Tech.: 3:553:40 4:40 4:10 4:25 3:25 3:403:25 3/16 15 15 15 15 15 60.001/4 REMARKS: 60.00 40.00 48.00 48.003:55 15 80.00 (in) 1/4 3/8 5/16 5/16 (min/in) Cole Garner Geotechnical 1070 West 124th Avenue, Ste. 300 Westminster, CO 80234 (min) T.M.C. 21.22.034 Infiltration Rate During IntervalWater Level Drop Enclave at Redwood (hh:mm) 3/3/2021 Hole diameter (in):2 Approx. Test Depth (in):60 Infiltration Rate During Interval (in/hr) 5.00 4.75 5.00 4.75 4.75 5.25 Average Infiltration Rate 4.85 Cole Garner Geotechnical 1070 West 124th Avenue, Ste. 300 Westminster, CO 80234 Field Infiltration Rate Test No. 10 (303) 996-2999 Project Name:Enclave at Redwood Date: Cole Garner Project No.:21.22.034 Eng./Tech.:T.M.C. Interval Start Time Interval End Time Length of Interval Water Level Drop 1 3/16 12.63 Infiltration Rate During Interval (hh:mm)(hh:mm)(min)(in)(min/in) 1 3/16 12.63 3:10 3:25 15 1 1/4 12.00 3:25 3:40 15 1 5/16 11.43 3:40 3:55 15 1 1/4 12.00 3:55 4:10 15 4:10 4:25 15 1 3/16 12.63 4:25 4:40 15 REMARKS:Cased borehole infiltration test method performed at a depth of approximately 5 feet below existing site grade. Test performed in the fine to coarse sand with silt and gravel stratum. Summit Scientific 303.277.9310 4653 Table Mountain Drive, Golden, Colorado 80403 Cole Garner Geotechnical RE: Enclave @ Redwood Westminster, CO 80234 1070 W 124th Ave, Suite 300 Patrick Maloney Paul Shrewsbury President Enclosed are the results of analyses for samples received by Summit Scientific on 03/04/21 08:30. If you have any questions concerning this report, please feel free to contact me. Sincerely, March 24, 2021 2103080Work Order # Project: Project Number: Project Manager: Reported: Cole Garner Geotechnical 1070 W 124th Ave, Suite 300 21.22.034 Patrick Maloney 03/24/21 14:19Westminster CO, 80234 Enclave @ Redwood S2 Sample ID Laboratory ID Matrix Date Sampled ANALYTICAL REPORT FOR SAMPLES Date Received MW-7 2103080-01 Water 03/03/21 14:00 03/04/21 08:30 Summit Scientific The results in this report apply to the samples analyzed in accordance with the chain of custody document. This analytical report must be reproduced in its entirety . Page 1 of 8 Project: Project Number: Project Manager: Reported: Cole Garner Geotechnical 1070 W 124th Ave, Suite 300 21.22.034 Patrick Maloney 03/24/21 14:19Westminster CO, 80234 Enclave @ Redwood S2 MW-7 2103080-01 (Water) Summit Scientific Dissolved Metals by EPA Method 200.8 03/03/21 14:00Date Sampled: Reporting Notes MethodAnalyzedPreparedBatchDilutionUnitsLimitResultAnalyte EPA 200.80.0963 BEC0130 03/05/21 03/05/21 ug/l 1Antimony0.0500 "1.27 """""Arsenic 0.600 ND """"""Beryllium 0.0500 "0.139 """""Cadmium 0.0500 ND """"""Chromium 1.00 "1.90 """""Copper 1.00 ND """"""Lead 0.500 "9.52 """""Nickel 1.00 "4.43 """""Selenium 1.00 ND """"""Silver 0.0500 ND """"""Thallium 0.0250 ND """"""Zinc 1.00 Dissolved Mercury by EPA Method 245.1 03/03/21 14:00Date Sampled: Reporting Notes MethodAnalyzedPreparedBatchDilutionUnitsLimitResultAnalyte ND EPA 245.103/10/21 03/11/21 ug/l BEC02091Mercury0.200 Summit Scientific The results in this report apply to the samples analyzed in accordance with the chain of custody document. This analytical report must be reproduced in its entirety . Page 4 of 8 Project: Project Number: Project Manager: Reported: Cole Garner Geotechnical 1070 W 124th Ave, Suite 300 21.22.034 Patrick Maloney 03/24/21 14:19Westminster CO, 80234 Enclave @ Redwood S2 Result Limit Reporting Units Level Spike Result Source %REC %REC Limits RPD RPD Limit Notes Analyte Dissolved Metals by EPA Method 200.8 - Quality Control Summit Scientific Batch BEC0130 - EPA 200.8 Blank (BEC0130-BLK1)Prepared & Analyzed: 03/05/21 Antimony ug/lND0.0500 Arsenic "ND 0.600 Beryllium "ND 0.0500 Cadmium "ND 0.0500 Chromium "ND 1.00 Copper "ND 1.00 Lead "ND 0.500 Nickel "ND 1.00 Selenium "ND 1.00 Silver "ND 0.0500 Thallium "ND 0.0250 Zinc "ND 1.00 LCS (BEC0130-BS1)Prepared & Analyzed: 03/05/21 Antimony ug/l27.1 0.0500 25.0 85-115108 Arsenic "543 0.600 500 85-115109 Beryllium "26.6 0.0500 25.0 85-115106 Cadmium "27.2 0.0500 25.0 85-115109 Chromium "530 1.00 500 85-115106 Copper "530 1.00 500 85-115106 Lead "265 0.500 250 85-115106 Nickel "533 1.00 500 85-115107 Selenium "47.0 1.00 50.0 85-11594.0 Silver "26.9 0.0500 25.0 85-115108 Thallium "13.4 0.0250 12.5 85-115107 Zinc "537 1.00 500 85-115107 Duplicate (BEC0130-DUP1)Prepared & Analyzed: 03/05/21 Source: 2103080-01 Antimony ug/l0.0829 0.0500 0.0963 2014.9 Arsenic "1.31 0.600 1.27 202.64 Beryllium "0.0360 0.0500 0.0377 204.45 Cadmium "0.150 0.0500 0.139 208.08 Chromium "0.582 1.00 0.551 205.50 Copper "1.73 1.00 1.90 208.93 Lead "0.134 0.500 0.132 201.55 Nickel "8.86 1.00 9.52 207.19 Selenium "ND 1.00 4.43 20 Silver "ND 0.0500 0.00635 20 Summit Scientific The results in this report apply to the samples analyzed in accordance with the chain of custody document. This analytical report must be reproduced in its entirety . Page 5 of 8 Project: Project Number: Project Manager: Reported: Cole Garner Geotechnical 1070 W 124th Ave, Suite 300 21.22.034 Patrick Maloney 03/24/21 14:19Westminster CO, 80234 Enclave @ Redwood S2 Result Limit Reporting Units Level Spike Result Source %REC %REC Limits RPD RPD Limit Notes Analyte Dissolved Metals by EPA Method 200.8 - Quality Control Summit Scientific Batch BEC0130 - EPA 200.8 Duplicate (BEC0130-DUP1)Prepared & Analyzed: 03/05/21 Source: 2103080-01 Thallium ug/lND0.0250 ND 20 Zinc "ND 1.00 ND 20 Matrix Spike (BEC0130-MS1)Prepared & Analyzed: 03/05/21 Source: 2103080-01 Antimony ug/l27.6 0.0500 25.0 0.0963 70-130110 Arsenic "569 0.600 500 1.27 70-130114 Beryllium "25.0 0.0500 25.0 0.0377 70-13099.8 Cadmium "27.3 0.0500 25.0 0.139 70-130109 Chromium "536 1.00 500 0.551 70-130107 Copper "537 1.00 500 1.90 70-130107 Lead "265 0.500 250 0.132 70-130106 Nickel "545 1.00 500 9.52 70-130107 Selenium "44.4 1.00 50.0 4.43 70-13080.0 Silver "26.9 0.0500 25.0 0.00635 70-130107 Thallium "13.4 0.0250 12.5 ND 70-130107 Zinc "539 1.00 500 ND 70-130108 Matrix Spike Dup (BEC0130-MSD1)Prepared & Analyzed: 03/05/21 Source: 2103080-01 Antimony ug/l26.2 0.0500 25.0 0.0963 2570-130105 4.99 Arsenic "548 0.600 500 1.27 2570-130109 3.68 Beryllium "23.2 0.0500 25.0 0.0377 2570-13092.5 7.64 Cadmium "26.2 0.0500 25.0 0.139 2570-130104 4.05 Chromium "513 1.00 500 0.551 2570-130103 4.39 Copper "522 1.00 500 1.90 2570-130104 2.75 Lead "248 0.500 250 0.132 2570-13099.2 6.72 Nickel "527 1.00 500 9.52 2570-130104 3.18 Selenium "42.0 1.00 50.0 4.43 2570-13075.2 5.54 Silver "25.2 0.0500 25.0 0.00635 2570-130101 6.20 Thallium "12.5 0.0250 12.5 ND 2570-130100 6.61 Zinc "519 1.00 500 ND 2570-130104 3.80 Summit Scientific The results in this report apply to the samples analyzed in accordance with the chain of custody document. This analytical report must be reproduced in its entirety . Page 6 of 8 Project: Project Number: Project Manager: Reported: Cole Garner Geotechnical 1070 W 124th Ave, Suite 300 21.22.034 Patrick Maloney 03/24/21 14:19Westminster CO, 80234 Enclave @ Redwood S2 Result Limit Reporting Units Level Spike Result Source %REC %REC Limits RPD RPD Limit Notes Analyte Dissolved Mercury by EPA Method 245.1 - Quality Control Summit Scientific Batch BEC0209 - EPA 245.1 Blank (BEC0209-BLK1)Prepared: 03/10/21 Analyzed: 03/11/21 Mercury ug/lND0.200 LCS (BEC0209-BS1)Prepared: 03/10/21 Analyzed: 03/11/21 Mercury ug/l2.17 0.200 2.50 85-11586.8 Duplicate (BEC0209-DUP1)Prepared: 03/10/21 Analyzed: 03/11/21 Source: 2103131-01 Mercury ug/l0.210 0.200 0.210 2000.00 Matrix Spike (BEC0209-MS1)Prepared: 03/10/21 Analyzed: 03/11/21 Source: 2103131-01 Mercury ug/l2.22 0.200 2.50 0.210 75-12580.4 Matrix Spike Dup (BEC0209-MSD1)Prepared: 03/10/21 Analyzed: 03/11/21 Source: 2103131-01 Mercury ug/l2.27 0.200 2.50 0.210 2075-12582.4 2.23 Summit Scientific The results in this report apply to the samples analyzed in accordance with the chain of custody document. This analytical report must be reproduced in its entirety . Page 7 of 8 03/15/21 Technical Report for Summit Scientific 2103080 SGS Job Number: DA32947 Sampling Date: 03/03/21 Report to: Summit Scientific 4653 Table Mountain Dr Golden, CO 80403 pshrewsbury@s2scientific.com; mpremer@s2scientific.com; mpremer@s2scientific.com ATTN: Paul Shrewsbury Total number of pages in report: Certifications: CO (CO00049), NE (NE-OS-06-04), ND (R-027), UT (NELAP CO00049) LA (LA150028), TX (T104704511), WY (8TMS-L) This report shall not be reproduced, except in its entirety, without the written approval of SGS. Test results relate only to samples analyzed. SGS North America Inc. • 4036 Youngfield St. • Wheat Ridge, CO 80033-3862 • tel: 303-425-6021 • fax: 303-425-6854 Test results contained within this data package meet the requirements of the National Environmental Laboratory Accreditation Program and/or state specific certification programs as applicable. Client Service contact: Carissa Cumine 303-425-6021 Jason Savoie General Manager Wheat Ridge, CO 03/15/21 e-Hardcopy 2.0 Automated Report 13 SGS is the sole authority for authorizing edits or modifications to this document. Unauthorized modification of this report is strictly prohibited. Review standard terms at: http://www.sgs.com/en/terms-and-conditions The results set forth herein are provided by SGS North America Inc. Please share your ideas about how we can serve you better at: EHS.US.CustomerCare@sgs.com 1 of 13 DA32947 Table of Contents -1- Sections: Section 1: Sample Summary ...................................................................................................3 Section 2: Summary of Hits ....................................................................................................4 Section 3: Sample Results ........................................................................................................5 3.1: DA32947-1: MW-7 .......................................................................................................6 Section 4: Misc. Forms ............................................................................................................11 4.1: Chain of Custody ...........................................................................................................12 12342 of 13 DA32947 SGS North America Inc. Sample Summary Summit Scientific Job No:DA32947 2103080 Sample Collected Matrix Client Number Date Time By Received Code Type Sample ID This report contains results reported as ND = Not detected. The following applies: Organics ND = Not detected above the MDL DA32947-1 03/03/21 14:00 03/05/21 AQ Water MW-7 3 of 13 DA329471 Summary of Hits Page 1 of 1 Job Number:DA32947 Account:Summit Scientific Project:2103080 Collected:03/03/21 Lab Sample ID Client Sample ID Result/ Analyte Qual RL MDL Units Method DA32947-1 MW-7 bis(2-Ethylhexyl)phthalate 3.6 1.9 0.48 ug/l EPA 625.1 4 of 13 DA329472 SGS North America Inc. Sample Results Report of Analysis Wheat Ridge, CO Section 3 5 of 13 DA329473 SGS North America Inc. Report of Analysis Page 1 of 2 Client Sample ID:MW-7 Lab Sample ID:DA32947-1 Date Sampled:03/03/21 Matrix:AQ - Water Date Received:03/05/21 Method:EPA 624.1 Percent Solids:n/a Project:2103080 File ID DF Analyzed By Prep Date Prep Batch Analytical Batch Run #1 a 7V71554.D 1 03/10/21 23:59 JB n/a n/a V7V3597 Run #2 Purge Volume Run #1 5.0 ml Run #2 VOA PPL List CAS No.Compound Result RL MDL Units Q 107-02-8 Acrolein ND 10 7.0 ug/l 107-13-1 Acrylonitrile ND 5.0 4.0 ug/l 71-43-2 Benzene ND 1.0 0.50 ug/l 75-27-4 Bromodichloromethane ND 2.0 0.55 ug/l 75-25-2 Bromoform ND 4.0 1.5 ug/l 56-23-5 Carbon tetrachloride ND 2.0 0.50 ug/l 108-90-7 Chlorobenzene ND 1.0 0.50 ug/l 75-00-3 Chloroethane ND 4.0 2.0 ug/l 110-75-8 2-Chloroethyl vinyl ether ND 2.0 1.0 ug/l 67-66-3 Chloroform ND 2.0 1.0 ug/l 124-48-1 Dibromochloromethane ND 2.0 0.50 ug/l 95-50-1 o-Dichlorobenzene ND 1.0 0.50 ug/l 541-73-1 m-Dichlorobenzene ND 1.0 0.50 ug/l 106-46-7 p-Dichlorobenzene ND 2.0 1.0 ug/l 75-71-8 Dichlorodifluoromethane ND 4.0 3.0 ug/l 75-34-3 1,1-Dichloroethane ND 2.0 1.0 ug/l 107-06-2 1,2-Dichloroethane ND 2.0 1.0 ug/l 75-35-4 1,1-Dichloroethylene ND 2.0 1.0 ug/l 156-59-2 cis-1,2-Dichloroethylene ND 2.0 1.0 ug/l 156-60-5 trans-1,2-Dichloroethylene ND 2.0 1.0 ug/l 78-87-5 1,2-Dichloropropane ND 2.0 1.0 ug/l 10061-01-5 cis-1,3-Dichloropropene ND 2.0 1.0 ug/l 10061-02-6 trans-1,3-Dichloropropene ND 2.0 1.0 ug/l 100-41-4 Ethylbenzene ND 1.0 0.50 ug/l 74-83-9 Methyl bromide ND 4.0 2.0 ug/l 74-87-3 Methyl chloride ND 2.0 1.0 ug/l 75-09-2 Methylene chloride ND 4.0 2.0 ug/l 79-34-5 1,1,2,2-Tetrachloroethane ND 1.0 0.50 ug/l 127-18-4 Tetrachloroethylene ND 1.0 0.50 ug/l 108-88-3 Toluene ND 1.0 0.50 ug/l 71-55-6 1,1,1-Trichloroethane ND 2.0 1.0 ug/l 79-00-5 1,1,2-Trichloroethane ND 2.0 1.0 ug/l ND = Not detected MDL = Method Detection Limit J = Indicates an estimated value RL = Reporting Limit B = Indicates analyte found in associated method blank E = Indicates value exceeds calibration range N = Indicates presumptive evidence of a compound 6 of 13 DA3294733.1 SGS North America Inc. Report of Analysis Page 2 of 2 Client Sample ID:MW-7 Lab Sample ID:DA32947-1 Date Sampled:03/03/21 Matrix:AQ - Water Date Received:03/05/21 Method:EPA 624.1 Percent Solids:n/a Project:2103080 VOA PPL List CAS No.Compound Result RL MDL Units Q 79-01-6 Trichloroethylene ND 1.0 0.50 ug/l 75-69-4 Trichlorofluoromethane ND 4.0 2.0 ug/l 75-01-4 Vinyl chloride ND 2.0 1.0 ug/l 1330-20-7 Xylene (total)ND 1.0 1.0 ug/l CAS No.Surrogate Recoveries Run# 1 Run# 2 Limits 1868-53-7 Dibromofluoromethane 102%60-140% 17060-07-0 1,2-Dichloroethane-D4 95%60-140% 2037-26-5 Toluene-D8 93%60-140% 460-00-4 4-Bromofluorobenzene 99%60-140% (a) Sample was not preserved to a pH < 2. ND = Not detected MDL = Method Detection Limit J = Indicates an estimated value RL = Reporting Limit B = Indicates analyte found in associated method blank E = Indicates value exceeds calibration range N = Indicates presumptive evidence of a compound 7 of 13 DA3294733.1 SGS North America Inc. Report of Analysis Page 1 of 2 Client Sample ID:MW-7 Lab Sample ID:DA32947-1 Date Sampled:03/03/21 Matrix:AQ - Water Date Received:03/05/21 Method:EPA 625.1 EPA 625.1 Percent Solids:n/a Project:2103080 File ID DF Analyzed By Prep Date Prep Batch Analytical Batch Run #1 1G152717.D 1 03/08/21 12:45 DC 03/06/21 OP19908 E1G2895 Run #2 Initial Volume Final Volume Run #1 1050 ml 1.0 ml Run #2 ABN 625PPL List CAS No.Compound Result RL MDL Units Q 59-50-7 4-Chloro-3-methyl phenol ND 1.9 0.48 ug/l 95-57-8 2-Chlorophenol ND 1.9 0.48 ug/l 120-83-2 2,4-Dichlorophenol ND 1.9 0.48 ug/l 87-65-0 2,6-Dichlorophenol ND 1.9 0.76 ug/l 105-67-9 2,4-Dimethylphenol ND 1.9 0.95 ug/l 534-52-1 4,6-Dinitro-o-cresol ND 9.5 7.1 ug/l 51-28-5 2,4-Dinitrophenol ND 9.5 7.1 ug/l 88-75-5 2-Nitrophenol ND 1.9 0.53 ug/l 100-02-7 4-Nitrophenol ND 19 7.1 ug/l 87-86-5 Pentachlorophenol ND 4.8 3.8 ug/l 108-95-2 Phenol ND 1.9 0.48 ug/l 88-06-2 2,4,6-Trichlorophenol ND 1.9 0.48 ug/l 83-32-9 Acenaphthene ND 1.9 0.48 ug/l 208-96-8 Acenaphthylene ND 1.9 0.48 ug/l 120-12-7 Anthracene ND 1.9 0.48 ug/l 92-87-5 Benzidine ND 19 7.1 ug/l 56-55-3 Benzo(a)anthracene ND 1.9 0.48 ug/l 205-99-2 Benzo(b)fluoranthene ND 1.9 0.48 ug/l 191-24-2 Benzo(g,h,i)perylene ND 1.9 0.48 ug/l 207-08-9 Benzo(k)fluoranthene ND 1.9 0.48 ug/l 50-32-8 Benzo(a)pyrene ND 1.9 0.48 ug/l 101-55-3 4-Bromophenyl phenyl ether ND 1.9 0.53 ug/l 85-68-7 Butyl benzyl phthalate ND 1.9 0.48 ug/l 111-91-1 bis(2-Chloroethoxy)methane ND 1.9 0.48 ug/l 111-44-4 bis(2-Chloroethyl)ether ND 1.9 0.62 ug/l 108-60-1 2,2'-Oxybis(1-chloropropane)ND 1.9 0.48 ug/l 91-58-7 2-Chloronaphthalene ND 1.9 0.56 ug/l 7005-72-3 4-Chlorophenyl phenyl ether ND 1.9 0.50 ug/l 218-01-9 Chrysene ND 1.9 0.48 ug/l 53-70-3 Dibenzo(a,h)anthracene ND 1.9 0.48 ug/l 91-94-1 3,3'-Dichlorobenzidine ND 4.8 0.48 ug/l 121-14-2 2,4-Dinitrotoluene ND 1.9 0.48 ug/l ND = Not detected MDL = Method Detection Limit J = Indicates an estimated value RL = Reporting Limit B = Indicates analyte found in associated method blank E = Indicates value exceeds calibration range N = Indicates presumptive evidence of a compound 8 of 13 DA3294733.1 SGS North America Inc. Report of Analysis Page 2 of 2 Client Sample ID:MW-7 Lab Sample ID:DA32947-1 Date Sampled:03/03/21 Matrix:AQ - Water Date Received:03/05/21 Method:EPA 625.1 EPA 625.1 Percent Solids:n/a Project:2103080 ABN 625PPL List CAS No.Compound Result RL MDL Units Q 606-20-2 2,6-Dinitrotoluene ND 1.9 0.48 ug/l 122-66-7 1,2-Diphenylhydrazine ND 1.9 0.48 ug/l 84-74-2 Di-n-butyl phthalate ND 1.9 0.69 ug/l 117-84-0 Di-n-octyl phthalate ND 1.9 0.48 ug/l 84-66-2 Diethyl phthalate ND 1.9 0.48 ug/l 131-11-3 Dimethyl phthalate ND 1.9 0.48 ug/l 117-81-7 bis(2-Ethylhexyl)phthalate 3.6 1.9 0.48 ug/l 206-44-0 Fluoranthene ND 1.9 0.54 ug/l 86-73-7 Fluorene ND 1.9 0.48 ug/l 118-74-1 Hexachlorobenzene ND 1.9 0.48 ug/l 87-68-3 Hexachlorobutadiene ND 1.9 0.48 ug/l 77-47-4 Hexachlorocyclopentadiene ND 1.9 0.48 ug/l 67-72-1 Hexachloroethane ND 1.9 0.48 ug/l 193-39-5 Indeno(1,2,3-cd)pyrene ND 4.8 0.48 ug/l 78-59-1 Isophorone ND 1.9 0.48 ug/l 91-20-3 Naphthalene ND 1.9 0.48 ug/l 98-95-3 Nitrobenzene ND 1.9 0.50 ug/l 62-75-9 N-Nitrosodimethylamine ND 4.8 3.8 ug/l 86-30-6 N-Nitrosodiphenylamine ND 1.9 0.48 ug/l 621-64-7 N-Nitroso-di-n-propylamine ND 1.9 0.52 ug/l 85-01-8 Phenanthrene ND 1.9 0.48 ug/l 129-00-0 Pyrene ND 1.9 0.48 ug/l 120-82-1 1,2,4-Trichlorobenzene ND 1.9 0.48 ug/l CAS No.Surrogate Recoveries Run# 1 Run# 2 Limits 367-12-4 2-Fluorophenol 30%2-140% 4165-62-2 Phenol-d5 22%8-424% 118-79-6 2,4,6-Tribromophenol 57%10-140% 4165-60-0 Nitrobenzene-d5 63%15-314% 321-60-8 2-Fluorobiphenyl 54%47-140% 1718-51-0 Terphenyl-d14 44% a 59-140% (a) Outside control limits due to possible matrix interference. Insufficient sample for repreparation and reanalysis. ND = Not detected MDL = Method Detection Limit J = Indicates an estimated value RL = Reporting Limit B = Indicates analyte found in associated method blank E = Indicates value exceeds calibration range N = Indicates presumptive evidence of a compound 9 of 13 DA3294733.1 SGS North America Inc. Report of Analysis Page 1 of 1 Client Sample ID:MW-7 Lab Sample ID:DA32947-1 Date Sampled:03/03/21 Matrix:AQ - Water Date Received:03/05/21 Method:SW846 8270C BY SIM SW846 3510C Percent Solids:n/a Project:2103080 File ID DF Analyzed By Prep Date Prep Batch Analytical Batch Run #1 3G45770.D 1 03/11/21 17:29 DC 03/10/21 OP19917 E3G2288 Run #2 Initial Volume Final Volume Run #1 1060 ml 1.0 ml Run #2 CAS No.Compound Result RL MDL Units Q 123-91-1 1,4-Dioxane ND 0.47 0.19 ug/l CAS No.Surrogate Recoveries Run# 1 Run# 2 Limits 4165-60-0 Nitrobenzene-d5 49%10-130% ND = Not detected MDL = Method Detection Limit J = Indicates an estimated value RL = Reporting Limit B = Indicates analyte found in associated method blank E = Indicates value exceeds calibration range N = Indicates presumptive evidence of a compound 10 of 13 DA3294733.1 SGS North America Inc. Misc. Forms Custody Documents and Other Forms Includes the following where applicable: • Chain of Custody Wheat Ridge, CO Section 4 11 of 13 DA329474 DA32947: Chain of Custody Page 1 of 2 12 of 13 DA3294744.1 SGS Sample Receipt Summary Job Number:DA32947 Client:SUMMIT SCIENTIFIC Date / Time Received:3/5/2021 2:00:00 PM Delivery Method: Project:2103080 4. No. Coolers:1 Airbill #'s:HD Cooler Security 1. Custody Seals Present: Y or N 2. Custody Seals Intact: 3. COC Present: 4. Smpl Dates/Time OK 2. Cooler temp verification: Cooler Temperature Y or N 1. Temp criteria achieved: 3. Cooler media: IR Gun; Ice (Bag) Quality Control Preservation Y or N N/A 1. Trip Blank present / cooler: 2. Trip Blank listed on COC: 3. Samples preserved properly: 4. VOCs headspace free: Sample Integrity - Documentation Y or N 1. Sample labels present on bottles: 2. Container labeling complete: 3. Sample container label / COC agree: Sample Integrity - Condition Y or N 1. Sample recvd within HT: 3. Condition of sample: 2. All containers accounted for: Sample Integrity - Instructions 1. Analysis requested is clear: 2. Bottles received for unspecified tests 3. Sufficient volume recvd for analysis: 4. Compositing instructions clear: 5. Filtering instructions clear: Intact Y or N Comments Y or N N/A Cooler Temps (Initial/Adjusted):#1: (3.8/3.8); DA32947: Chain of Custody Page 2 of 2 13 of 13 DA3294744.1 Project: Project Number: Project Manager: Reported: Cole Garner Geotechnical 1070 W 124th Ave, Suite 300 21.22.034 Patrick Maloney 03/24/21 14:19Westminster CO, 80234 Enclave @ Redwood S2 Notes and Definitions Sample results reported on a dry weight basis Relative Percent DifferenceRPD dry Not ReportedNR Analyte NOT DETECTED at or above the reporting limitND Analyte DETECTEDDET