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HomeMy WebLinkAbout1.03 Geotech Analysis• • • PRELIMINARY GEOTECHNICAL INVESTIGATION CERISE RANCH GARFIELD AND EAGLE COUNTIES, COLORADO Prepared For: MR. ART KLEINSTEIN c/o The Land Studio P.O. Box 107 Basalt, CO 81621 Attention: Mr. Doug Pratte Job No. GS -2933 January 27, 2000 CTL/THOMPSON, INC. CONSULTING ENGINEERS 234 CENTER DRIVE • GLENWOOD SPRINGS, COLORADO 81601 ■ (970) 945-2809 • • • SCOPE This report presents the results of our Preliminary Geotechnical Investigation for the Cerise Ranch in Garfield and Eagle Counties, Colorado. The site is planned fora residential development. The subsurface exploration and engineering analysis were performed to provide an overview of geotechnical considerations to assist in planning the development of the subdivision and developing preliminary foundation recommendations. After building footprints are finalized and building plans are known, additional design level geotechnical studies are recommended for individual buildings. The report identifies issues believed to be common throughout the site and to most of the Tots and provides preliminary geotechnical discussion and recommendations regarding overlot grading, infrastructure installation, building site excavations and fills, foundation construction, lateral earth pressures and floor slabs. Design level pavement recommendations are part of this report. Our report includes a description of the subsoil conditions found in our exploratory borings and exploratory test pits and a discussion of site development as influenced by geotechnical considerations. This investigation was performed in accordance with our Proposal GS -99-220, dated November 23, 1999. This report is based on conditions disclosed by our exploratory drilling and excavation, site observations, results of laboratory tests, engineering analysis of field and laboratory data and our experience. The criteria presented in this report are intended for planning purposes. A summary of our conclusions is presented below. SUMMARY OF CONCLUSIONS 1. We discovered no geotechnical constraint that would preclude the planned site development as we understand it. The subsoil conditions are generally favorable for the proposed residential development. 2. Our exploratory borings and pits penetrated a comparatively thin surficial layer of organic, sandy clays above a nil to 25feet thick layer of soft to very stiff, silty to sandy clays with clayey sand lenses underlain by medium dense to very dense, clayey to sandy gravels MR. ART KLEINSTEIN CERISE RANCH CTL/T GS -2933 1 • SCOPE SUMMARY OF CONCLUSIONS 1 SITE DESCRIPTION 3 PROPOSED DEVELOPMENT 3 SUBSURFACE CONDITIONS 4 Clays 5 Gravels and Sands 5 Ground Water 5 SITE DEVELOPMENT 6 Overlot Grading and Road Grading 6 Utility Construction 7 PRELIMINARY BUILDING CONSIDERATIONS 8 IIIPreliminary Foundation Considerations 8 Interior Floors and Exterior Slabs -On -Grade 9 Below Grade Walls and Basement Construction 10 EARTH RETAINING STRUCTURES 11 PAVEMENTS 12 Materials and Construction 13 Maintenance 14 SURFACE DRAINAGE 14 LIMITATIONS 15 FIGURE 1 - APPROXIMATE LOCATIONS OF EXPLORATORY BORINGS AND PITS FIGURES 2 AND 4 - SUMMARY LOGS OF EXPLORATORY BORINGS AND PITS FIGURES 5 THROUGH 9- SWELL/CONSOLIDATION TEST RESULTS FIGURES 10 THROUGH 14 - GRADATION TEST RESULTS TABLE 1 - SUMMARY OF LABORATORY TEST RESULTS APPENDIX A - PAVEMENT DESIGN NOMOGRAPHS AND LABORATORY TESTING APPENDIX B - PAVEMENT CONSTRUCTION RECOMMENDATIONS APPENDIX C - PAVEMENT MAINTENANCE RECOMMENDATIONS TABLE OF CONTENTS 1 MR. ART KLEINSTEIN CERISE RANCH CTLJT GS -2933 • • • SCOPE This report presents the results of our Preliminary Geotechnical Investigation for the Cerise Ranch in Garfield and Eagle Counties, Colorado. The site is planned for a residential development. The subsurface exploration and engineering analysis were performed to provide an overview of geotechnical considerations to assist in planning the development of the subdivision and developing preliminary foundation recommendations. After building footprints are finalized and building plans are known, additional design level geotechnical studies are recommended for individual buildings. The report identifies issues believed to be common throughout the site and to most of the lots and provides preliminary geotechnical discussion and recommendations regarding overlot grading, infrastructure installation, building site excavations and fills, foundation construction, lateral earth pressures and floor slabs. Design level pavement recommendations are part of this report. Our report includes a description of the subsoil conditions found in our exploratory borings and exploratory test pits and a discussion of site development as influenced by geotechnical considerations. This investigation was performed in accordance with our Proposal GS -99-220, dated November 23, 1999. This report is based on conditions disclosed by our exploratory drilling and excavation, site observations, results of laboratory tests, engineering analysis of field and laboratory data and our experience. The criteria presented in this report are intended for planning purposes. A summary of our conclusions is presented below. SUMMARY OF CONCLUSIONS 1. We discovered no geotechnical constraint that would preclude the planned site development as we understand it. The subsoil conditions are generally favorable for the proposed residential development. 2. Our exploratory borings and pits penetrated a comparatively thin surficial layer of organic, sandy clays above a nil to 25 feet thick layer of soft to very stiff, silty to sandy clays with clayey sand lenses underlain by medium dense to very dense, clayey to sandy gravels MR. ART KLEINSTEIN CERISE RANCH CTLIT GS -2933 1 • • • with cobbles and boulders and silty sand lenses. In our TH-2, a layer of very loose to loose, silty sands was between the gravels and clays. Free ground water was found at 8 to 23 feet deep in our TH-2 through TH-6 and TH-8 during our field investigations. 3. In general, we judge the natural clays to be moderately to highly compressible. In some areas our exploratory borings penetrated clays that we judge to be expansive. The natural gravels and sands were judged to possess a low consolidation potential. 4. We anticipate spread footings placed on native soils will be the recommended foundation type on Tots where gravels are exposed at foundation elevations. Where footings will be supported by gravels a comparatively high maximum allowable soil bearing pressure will likely be appropriate. Where footings will be supported by moderate to highly compressible clays, the soils will need to be subexcavated to the native gravels or to a minimum of 3 or 4 vertical feet below the bottom of footings and replaced with densely compacted structural fill. Footings with a minimum dead load may be recommended where expansive clays are found at footing elevations. Design level soils and foundation investigations are recommended on a lot by lot basis to determine the appropriate foundation type for individual buildings and to develop design level criteria. 5. Preliminary data indicates concrete slabs -on -grade floors placed on the gravels or sands will perform satisfactory if the soils below slabs are not wetted. Where clays occur at floor subgrade elevations it will likely be recommended to remove and replace 1 to 2 feet of the clays below floor slabs with structural fill. 6. The gravels and sands will provide very good, and the clays fair to poor subgrade support for pavements. Minimum thickness pavement sections are appropriate where gravels occur at subgrade elevations. Thicker pavement sections or removal of 12 to 18 inches of clay subgrade and replacement with gravels and sand as a subbase layer are recommended in areas where clays are found at planned subgrade elevations. Pavement design recommendations are presented in the PAVEMENT section. 7. Control of surface drainage is important to the performance of foundations and interior and exterior slabs -on -grade. Surface drainage should be designed to provide rapid removal of surface runoff away from buildings and roads. MR. ART KLEINSTEIN CERISE RANCH CTUT GS -2933 2 • • • Eg SITE DESCRIPTION Cerise Ranch is an approximately 466 acre parcel located in the Roaring Fork River Valley. The majority of the site is in Garfield County with a small portion at the east end of the property located in Eagle County. Catherine Store is approximately 1 mile to the west. Highway 82 is along the south property boundary with the Roaring Fork River beyond to the south. The Dakota, Eagle Dakota and Soderberg Subdivisions are adjacent to the southeast, east and northeast, respectively. Agricultural land is to the west. Land to the north has not been built on. A residence and agricultural operation with several barns, sheds and outbuildings is located on the west part of the property. The Roaring Fork River Valley trends from the east, down to the west in the vicinity of Cerise Ranch. The site is situated on the north side of the valley floor and lower slopes of the valley sides. Ground surfaces drop steeply from the north down to the south on the valley sides, decreasing in steepness in a transition area at the edge of the valley and flattening on the valley floor. A small pond is on the east part of the property. Several irrigation ditches cross the property from east to west. Vegetation on the valley floor and edges consists of irrigated pasture grasses and weeds. On the slopes above the valley, vegetation consists of pinion and juniper trees and sparse weeds and brush. PROPOSED DEVELOPMENT We understand the parcel is to be developed for single family residential usage. Approximately 67 Tots ranging between 2 and 10 acres each for a total of approximately 155 acres will be developed. The remainder of the site will be open space. Access to the Tots will be provided by constructing approximately 10,000 lineal feet of roadway. Sewer service will be individual sewage disposal systems (ISDS). Water service will be centralized. MR. ART KLEINSTEIN CERISE RANCH CTL/T GS -2933 3 • • • SUBSURFACE CONDITIONS Subsurface conditions were investigated by drilling eight (8) exploratory borings, eight (8) pavement subgrade borings and excavating six (6) exploratory test pits at the approximate locations shown on Figure 1. Our borings were drilled using an all terrain drill rig and 4 -inch diameter, continuous flight auger. Exploratory test pits were excavated with a Targe trackhoe. Subsurface exploration operations were directed by our representative who logged the soils and obtained samples for laboratory testing. Graphic Togs of the soils found in our borings and test pits and results of field penetration resistance tests are presented on Figures 2 through 4. Penetration resistance tests were performed in borings by driving a modified California sampler or standard barrel sampler with a 140 pound weight falling 30 inches. Local experience indicates penetration resistance tests using a California sampler are similar to the results of a standard penetration test. The modified California sampler results in a 2 -inch diameter by 4 inch long sample suitable for many laboratory tests. Samples obtained from our borings and test pits were returned to our laboratory where they were visually classified and typical samples selected for testing. Laboratory test results are presented on Figures 5 through 14 and summarized on Table 1. Our exploratory borings and pits penetrated a comparatively thin surficial layer of organic, sandy clays above a nil to 25 feet thick layer of soft to very stiff, silty to sandy clays with clayey sand lenses underlain by medium dense to very dense, clayey to sandy gravels with cobbles and boulders and silty sand lenses. In our TH-2, a layer of very loose to loose, silty sands was between the gravels and clays. Free ground water was found at 8 to 23 feet deep in our TH-2 through TH-6 and TH-8 during our field investigations. A description of the individual soils units found are presented in the following paragraphs. MR. ART KLEINSTEIN CERISE RANCH CTL/T GS -2933 4 • • Clays A nil to 25 feet thick layer of soft to very stiff, moist to wet, sandy to silty clays with clayey sand and sandy silt lenses was found. The soils are the result of weathering and downslope movement of deposits of the parent sedimentary rock. Clay samples subjected to one dimensional swell/consolidation testing to judge volume change potential exhibited varying characteristics from a high consolidation to a slight expansive potential. The clays will likely need to be subexcavated and replaced as densified structural fill to support Tight foundation loads. Gravels and Sands Gravel soils were found at varying depths at most boring and pit locations. The gravels were predominantly silty to clayey with cobbles and boulders with occasional thin to moderately thick silty to clayey sand lenses. The gravels were medium dense to very dense and moist to wet. Drilling in dense gravel alluvium with auger equipment was difficult due to cobbles and boulders and drilling refusal was encountered in several borings. The gravels are capable of supporting moderate to high foundation Toads. Lateral loads on walls will be lower where the gravel soils are used as backfill than where clay backfill is used. Ground Water Ground water was found in our exploratory borings TH-2, TH-3 through TH-6 and TH-8 during our field investigation. Ground water levels varied from 6 to 25 feet deep. Our field exploration was in the winter prior to the annual spring runoff period. The ground water level will likely rise during, and for a period after, spring snow melt. We anticipate ground water levels will rise to above basement floor elevations to at or near the ground surface on lower parts of the parcel. At higherelevations to the north, a perched water table could occur that may effect basement construction. Ground water should be evaluated on a lot by lot basis to determine MR. ART KLEINSTEIN CERISE RANCH CTUT GS -2933 5 • • the feasibility of basement construction. We installed PVC pipe at several locations throughout the site to allow future measurements to ground water. SITE DEVELOPMENT The following sections present recommendations and discusses overlot grading and road building and utility installation. Overlot Grading and Road Grading Grading plans were not prepared at this writing. Because the natural topography is comparatively flat overlot grading is anticipated to be minimal for most of the site. Where earthwork is required to level the ground surface it appears maximum cuts and fills will generally be on the order of 10 feet. Deeper cuts and thicker fill (near 20 vertical feet) will likely be required to build road embankments to provide access to the northwest part of the development. Many of our exploratory borings and pits encountered Targe cobbles or boulders. Boulders to 4 feet in diameter were observed in test pit excavations. We believe earthwork can be accomplished with Targe earthmoving equipment such as D-8 dozers with ripper blades and trackhoes. Subgrade for interior subdivision roads will be native clays and gravels. The clays will provide comparatively poor subgrade support characteristics. The gravels will provide good to excellent subgrade support for pavements. Areas to receive fill must be properly prepared. The area below the new fill should be stripped to the natural soils free of organics, debris or other deleterious materials. "Topsoil" is probably 0.5 feet thick over much of the road alignments. The exposed soils should be prepared for fill placement by scarifying the upper 6 inches, moisture treating and compacting. Areas to receive fill should be proof rolled with MR. ART KLEINSTEIN CERISE RANCH CTLJT GS•2933 • i • a heavy (18 kip/axle) pneumatic tire vehicle such as a loaded tandem. Soft areas should be reworked or otherwise stabilized prior to placing fill. Fill placed below roads should be the on site soils or similar and be placed in 8 inch maximum loose lifts, moisture treated to within 2 percent of optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698). The on-site soils free of organics or rock larger than 6 inches in diameter or other deleterious materials can be used as fill to build road platforms. Fill part of overlot grading or road building should be placed in 8 inch maximum, loose lifts, moisture conditioned to between 2 percent below to 2 percent above optimum moisture content and compacted to at least 95 percent of maximum ASTM D 698 dry density. Fill placed on steeper cross slopes should be placed on excavated benches. The benches should be 8 to 12 feet wide to allow for heavy compaction equipment. Maximum bench height should be equal to or Tess than bench width. Placement and compaction of fill should be observed and tested during construction. Where fills • are below roads and are 10 feet or more thick , the fill should be allowed to "cure" throughout at least one winter and spring prior to placement of pavement. This normally allows the majority of consolidation to occur. Utility Construction Utility trenches should be sloped or shored to meet local, State and Federal safety regulations. Based on our subsurface exploration, , we believe the clays are Type B and the gravels are Type C based on OSHA standards. OSHA recommends temporary construction slopes no steeper than 1 to 1 (horizontal to vertical) for Type B and 1.5 to 1 (horizontal to vertical) for Type C soils above the water table. Excavation slopes specified by OSHA are dependent upon types of soils and groundwater conditions encountered. Seepage and groundwater conditions in excavations will down grade the OSHA soil type. Excavation slopes recommended above will ravel to near 4 to 1 (horizontal to vertical) or flatter below the water table. MR. ART KLEINSTEIN CERISE RANCH CTL/T GS -2933 7 • • • Contractors should identify the soils encountered in excavations and refer to OSHA standards to determine appropriate slopes. Excavations deeper than 20 feet need to be designed by a professional engineer. PRELIMINARY BUILDING CONSIDERATIONS Preliminary Foundation Considerations Depending on the area of the property, the near surface soils are silty to sandy clays or gravels with cobble and boulder with some silty to clayey sand lenses. The gravels are judged to be slightly compressible when the moisture content increases and Tight to moderate foundation loads, as normal with the type of construction planned, are applied. Buildings on lots where gravels occur at footing elevations lots can be founded with conventional spread footings on native soils. In other areas, native clays will be found at foundation elevations. Excavation to basement depths will likely remove the clays and expose gravels on some lots where clays are found. Where clay is found at foundation elevations it is most likely that foundation recommendations will be to remove the clays to the gravels or removal of at least 3 or 4 vertical feet of the clay from below bottom of footing elevations. The clay soils can then be reused to construct a mat of densified structural fill below the footings. Where expansive clays are encountered, we may recommend footings be designed for a minimum dead load. Footings placed on the native gravels can be sized with a maximum allowable soil pressure in the range of 3000 to 5000 psf. Footings bearing on structural fill built with the native clays can be sized with a maximum allowable soil bearing pressure in the range of 2000 to 3000 psf. Where expansive clays are exposed at footing elevations, foundation recommendations will likely be for footings with a minimum dead Toad of approximately 113 of the maximum allowable soil bearing pressure. MR. ART KLEINSTEIN CERISE RANCH CTLlr GS•2933 8 • • • Interior Floors and Exterior Slabs -On -Grade Excavations at the majority of the Tots will expose silty to sandy clays with some clayey sand lenses. On some lots clayey to sandy gravels will be exposed at slab -on -grade subgrade elevations. Where slabs will be supported by clays, we anticipate slabs -on -grade can bear on a 1 to 2 feet thick mat of densely compacted structural fill. Where expansive clays are exposed at subgrade elevations we anticipate structurally supported floors with a crawl space below will be recommended. As an alternative, removal of 1 to 2 vertical feet of the expansive clays and replacing with structural fill may be appropriate. Structural fill below floor slabs can be with the native on site clays. We anticipate slabs -on -grade floor construction on the native gravels or sands will be appropriate. Where slab -on -grade subgrade consists of gravels, the slabs can be placed on a thin leveling course placed on the native gravels. In areas of higher ground water it will likely be recommended that a minimum of 4 -inch thick layer of free draining gravel should immediately underlie slabs constructed below grade. This material should consist of maximum 2 -inch diameter aggregate with less than 50 percent passing the No. 4 sieve and Tess than 3 percent passing the No. 200 sieve. The free draining gravel will aid in drainage below the slabs and should be connected to a perimeter underdrain system. This layer will also act as a leveling course to provide a flat surface on which to place slabs. The gravel layer should not be placed below slabs -on -grade where the subgrade consists of clays. A gravel layer below floor slabs increases the possibility of a single water source wetting the entire area below slabs. To reduce the adverse effects of differential slab movement, floor slabs should be separated from all bearing walls and columns with expansion joints. Control joints should be used in floor slabs to reduce damage due to shrinkage cracking. MR. ART KLEINSTEIN CERISE RANCH CTLJT GS -2933 9 • • • Below Grade Walls and Basement Construction Our borings encountered ground water near or above anticipated basement floor elevations at lower elevations at the site. Ground water will rise during, and after snow melt in the spring. It should be anticipated that any excavation at this site may encounter ground water during the spring runoff. At higher elevations the ground water may be perched. Flood irrigation can also effect the ground water level in building excavations. Basement construction will likely not be practical for the lots at Cerise Ranch at lower elevations. At higher elevations basement construction may be feasible, however, under drain systems and waterproofing of foundation walls may be needed. In our opinion, basement feasibility should be addressed on a lot by lot basis as part of the geotechnical investigation to develop design level foundation recommendations. Foundation walls will be subjected to lateral earth pressures. Foundation walls at the back of some buildings may act a retaining walls. These walls are restrained and cannot move, therefore, they should be designed for the "at rest" lateral earth pressure. We believe an equivalent fluid density in the range of 50 to 60 pcf will be recommended to design for the "at rest" case when backfilled will be the native clays. The equivalent fluid density will be in the range of 45 to 55 pcf for the "at rest" case where gravel soils are the backfill. We recommend backfill behind the walls be compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698). Preliminary lateral earth pressure values do not include allowances for sloping backfill, hydrostatic pressure or surcharge Toads. Water from surface run-off (precipitation, snow melt, irrigation) frequently flows through backfill placed adjacent to foundation walls and collects on the surface of the comparatively impermeable soils occurring at the bottom of foundation excavations. This can cause damp or wet conditions in basement and crawl space areas of buildings. To reduce the accumulation of water we recommend that a foundation drain be placed adjacent to foundation walls. The drain should MR. ART KLEINSTEIN CERISE RANCH CTUT GS -2933 10 • • • consist of a 4 -inch diameter open joint or slotted PVC pipe encased in free draining gravel. Drain lines should be placed at each level of excavation and at least 1 foot below the lowest adjacent finished grade, and sloped at a minimum 1 percent to a positive gravity outfall. Free draining granular material used in the drain system should consist of minus 2 -inch aggregate with less than 50 percent passing the No. 4 sieve and Tess than 3 percent passing the No. 200 sieve. The drain gravel should be at least 1.5 feet thick. Adequate crawl space ventilation should be provided. EARTH RETAINING STRUCTURES Free standing retaining structures may be required. Several types of retaining structures are used in the area and could be considered. Some examples of different types of walls are listed below: Anchor Walls Tied -back walls tied back via soils nails or earth anchors Steel pile and lagging Continuous drilled pier walls Conventional Retaining Walls Reinforced concrete Crib walls Internally Stabilized Systems Mechanically stabilized earth (MSE) structures Friction reinforcement systems A "rock wall" is generally a landscaping feature. Rock walls greater than approximately 6 feet in height, in our opinion, do not provide adequate resistance to lateral loads. If rock walls are used, we suggest a maximum height of 6 feet. The wall should be battered at an angle of approximately 60 degrees. The width of the base of the wall should be at least 1/2 the height with a wall face no steeper than 3/4 to 1 (horizontal to vertical). MR. ART KLEINSTEIN CERISE RANCH CTLJT GS -2933 11 • • Retaining walls will be subjected to lateral earth pressure from wall backfill and surcharges. The lateral Toad on the wall is a function of wall movement. If the wall can move enough to mobilize the internal strength of the backfill, with movement and cracking of the surface behind the wall, the wall can be designed for the "active"earth pressure. If ground movement and cracking is not permitted, the wall should be designed for the "at rest" earth pressure. For the on site clays we suggest an equivalent fluid density in the range of 40 to 50 pcf be used to design for the "active" case, an equivalent fluid density of 50 to 60 pcf be used to design for the "at rest" cast and an equivalent fluid density of 225 to 275 pcf can be used for the "passive" case. For the on site gravels we suggest an equivalent fluid density of 40 to 45 pcf for the "active" case, 45 to 55 pcf for the "at rest" case and 250 to 300 psf for the "passive" case. These values are for preliminary wall designs. The design criteria should be confirmed prior to construction. These soils are generally not free draining. These soils exhibit small cohesive strength, and cohesion should be neglected in preliminary designs. Lateral earth pressure values do not include allowances for sloping backfill, hydrostatic pressures or surcharge loads. A foundation drain should be placed next to the foundation of any retaining wall. The 1 to 2 feet of backfill directly behind the wall should be a "clean" gravel imported to the site or a man made drain board product and provided with positive gravity discharge. PAVEMENTS Interior subdivision roads were classified as local streets servicing single family residences. Estimated traffic volumes were not known. We assumed an 18,000 pound single -axle Equivalent Daily Load Application (EDLA) of 5. If the actual traffic volumes are different we should be informed to allow re- evaluation of our recommended pavement design alternatives. Our design charts and design calculations are presented in Appendix A. Table A presents our pavement alternatives. MR. ART KLEINSTEIN CERISE RANCH CTUT GS -2933 12 • • • TABLE A PAVEMENT DESIGN ALTERNATIVES Location (see, Fig. A-1) Native Clay Subgrade EDLA 5 Native Gravel Subgrade Full Depth;`. Asphalt Concrete (AC) 5.5"AC 5.0" AC Asphalt Concrete (AC) ,& Aggregate Base (ABC) 3.0AC + 8.0"ABC + Fabric 3.0" AC + 5.0"ABC We have provided pavement design alternatives for areas where the subgrade will be the native clays and areas where the subgrade will be the native gravels. Approximate areas where we anticipate subgrade will consist of clays and areas where gravels are anticipated are shown on Figure A-1. The pavement design alternatives provided include full depth asphalt concrete on prepared subgrade and asphalt on aggregate base on a geotextile fabric. The aggregate base alternative retains a higher risk of distress than the full depth asphalt due to the potential increase of moisture in the subgrade. Independent from the type of flexible pavement chosen, care must be taken to provide proper maintenance throughout the life of the pavement to ensure a 20 -year service life. Materials and Construction The design of a pavement system is as much a function of the quality of the paving materials and construction as the support characteristics of the subgrade. The construction materials are assumed to possess sufficient quality as reflected by the strength coefficients used in the flexible pavement design calculations. These strength coefficients were developed through research and experience to simulate expected material of good quality, as explained in Appendix B. During construction, careful attention should be paid to the following details: MR. ART KLEINSTEIN CERISE RANCH CTUT GS -2933 13 • • • • Placement and compaction of trench backfill. • Compaction at curblines and around manholes and water valves. • Excavation of completed pavements for utility construction and repair. • Moisture treating or stabilization of the subgrade. • Design slopes of the adjacent ground and pavement to rapidly remove water from the pavement surface. Maintenance We recommend a preventive maintenance program be developed and followed for all pavement systems to assure the design life can be realized. Choosing to defer maintenance usually results in accelerated deterioration leading to higher future maintenance costs. A recommended maintenance program is outlined in Appendix C. SURFACE DRAINAGE Surface drainage will need to control and channelize surface water down, around and away from roads and buildings. Seasonal surface flows through building footprints need to be re-routed away from the buildings. Any areas of potential ponding water should be eliminated. The performance of foundations and concrete flatwork is influenced by moisture conditions in the subsoils. Wetting of foundation soils can be reduced by grading the ground surface to cause rapid run-off of water away from the buildings. Wetting or drying of the open foundation excavations should be avoided. The ground surface surrounding the buildings should be sloped to drain away from the buildings in all directions. We recommend a slope of at least 12 inches in the first 10 feet. Roof downspouts and drains should discharge well beyond the limits of all backfill. Buried discharge lines are not desirable. MR. ART KLEINSTEIN CERISE RANCH CTLIT GS -2933 14 • 1 • LIMITATIONS The criteria in this report is preliminary and not for construction of buildings. The criteria is intended for use in developing preliminary designs and construction of roadways and installation of utilities. Design level criteria can only be developed and published after review of grading and building plans for individual lots. Individual site specific investigations will be needed. Our exploratory borings and test pits were spaced to obtain a reasonably accurate picture of the subsurface. Variations in these subsurface conditions not shown by our exploratory borings will occur. Our reportwas based on conditions disclosed by our exploratory borings and test pits, results of laboratory testing, engineering analysis and our experience. Criteria presented reflects anticipated construction as we understand it. This investigation was conducted in a manner consistent with that level of care and skill ordinarily exercised by members of geotechnical engineers currently practicing under similar conditions in the locality of this project. No other warranty, express or implied, is made. If we can be of further service or if you have questions regarding this report, please call. Very truly yours, CTL/THOMPSON, IN Wilson L. "Liv" B Engineering Geol LB:JM:cd (5 copies sent) MR. ART KLEINSTEIN CERISE RANCH CTLJT GS -2933 15 ££6Z—SO '0N qor 31VWIXOJddd SNOIld001 0 AdOlV803dX3 0 0 z 0 -74 cn • 0 a /fly • • UP2,4417 - "kV*, IRS vi ft; �i0104 Ys ; O O MUM corn ;01/11.j.. 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GS -2933 10 100 NATURAL DRY UNIT WEIGHT 11 PCF NATURAL MOISTURE CONTENT= Swell Consolidation Test Results FIG. 5 4 • 7 6 5 4 3 2 0 2 3 4 z 0 ri Z5 a. <J O 6 z 0 I. I. I • 7 2 0 O 8 LJ • ,•.1 . . , . • , , ; : • . ; : I : • ; , • ;;;,, '',‘, ...., , ! • , I , ! ! , ! • ! • ! . • ! ! : • i , ! " , ; . , , . . • • • i ' 1 I j , . ' r , r , ; I ! ; - • ; I I , ! I' •• $ 4 I f j : , r , ! : ' , f I . . 4 4 . • 4 ; ' ' I : ; • • • 1 ' ! ' ! ; I ; : ; 4 • . . ! ; : ! ' : ' I I . I ;L.. ! • . - ......,......... . ..... ..-...... 7.. : ,- •,‘„ • .„....., .... • . 1 . , 1 , I : 1 i ! • , ; . . , , I . : ; ; : i r : ; • : , , . . . • • 1 I ' : • I i 4 ! i . • ; ; ' I ; ; ! : • : 1 . . . . . ! ' 1 ' ; ; ; : • ; I • ; , . . • 4 • : • I I , . ' . . , .. • , I ! ; ! I I 1 ' 1 ! 1 I . , • 1 . 4 1 ,.... .,;_,... • . ; ! _i ' : , • . , I : • .; , ........... ;-.• , • r .., • • i , ; . ; .i. ; ,.... I I! ' ; :!. . • , 7 : : 1 : • I I I . i I • ! ' I 1 • ! ! I , . ; '' ' 1 I 1 4 I : : ! 1 , , , • 47; ' I I , I ; l• : • ; • 7 •'. i ; 7 I .; ! • • z I • ! • , : i • ' I . ; ! • I . .- — ' .- • ' -4; ---4 . L--, 8 1 I I • ' 1 ! ---4!--"---H-H- - - - "H-- '-''' -; -4- - -I- • ' ! 1 I : I • ' ' • EXFANS ION; UNDER CONSTANT ! ! ! PRESSURE DUE TO WETTING f- - -!-- • 7-- I ' _ , . . , • ; • . . ; 1 1 ! ; . i ' • . i , . : r I • i ' r I . ' : ' i • ' . , , i ! " 1 I j i , . I 7 1 7 I ............... : I I ; ! ; ! • t 0 ; ; • • • - • ! ' 0.1 APPLIED PRESSURE — KSF Sample of CLAY , SANDY (CL) From TH-3 AT 19 FEET ••-• ,r771 1.0 10 100 NATURAL DRY UNIT WEIGHT= 96 PCF NATURAL MOISTURE CONTENT= 26.8 SweII Consolidation Test Results FIG. 6 • • • COMPRESSION % EXPANSION 5 6 7 8 ADDITIONAL MOVEMENT UNDER 'CONSTANT PRESSURE DUE TO E:717 NG, 1 11 + " I 0.1 APPLIED PRESSURE — KSF Sample of CLAY, SANDY (CL) From TI f-4 AT 4 FEET 1.0 10 100 NATURAL DRY UNIT WEIGHT= 112 PCF NATURAL MOISTURE CONTENT= 12.9 % Swell Consolidation Test Results FIG. 7 • • • 5 4 3 2 1 0 1 2 3 4 5 6 z 0 Z 7 dc U44 W 3° 8 z 0 E 9 cc 0 U 1 0 • ` ADDITIONAL MOVEMENT UNDER CONSTANT PRESSURE DUE TO WETTING: • • 0.1 APPLIED PRESSURE — KSF Sample of From CLAY, SANDY (CL) 1.0 TF1 -5 AT 14 FEET 10 100 NATURAL DRY UNIT WEIGHT= 99 PCF NATURAL MOISTURE CONTENT= 26.5 % Swell Consolidation Test Results FIG. 8 • • COMPRESSION % EXPANSION 7 6 5 4 3 2 0 2 3 4 5 6 7 8 • I i ;t NO MOVEMENT UNDER CONSTANT :PRESSURE, DUE TO WETTING 1 4.. 0 0 0 I 0.1 APPLIED PRESSURE — KSF Sample of From 1.0 CLAY, SANDY (CL) TH-6 AT 4 FEET rC_9077 10 100 NATURAL DRY UNIT WEIGHT= 1 05 PCF NATURAL MOISTURE CONTENT= 20.7 Swell Consolidation Test Results FIG. 9 HYDROMETER ANALYSIS 25 HP. 7 HP TIME READINGS 45 MIN. 15 MIN. 60. MIN. 19 MIN. 4MIN. 1 MIN. '200 '100 '50'40'30 '16 '10_'8 - 4 3/8' 314". 11/2' 3' 5"4"-80' SIEVE ANALYSIS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 100 90 80 - 70'.. __ O z 60. a 50 - L. 40. 30 20 10 0 .001 .002 .005 .009 .019 .037 .074 .149 .297 .590 1 19 2.0 2.38 4.76 0.42 DIAMETER OF PARTICLE IN MILLIMETERS - 20 30 40 9.52 19.1 36.1 76.2 0 1 50 60 70 80 90 100 127 200 152 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND FINE MEDIUM 1 COARSE GRAVEL FINE 1 COARSE 1 COBBLES PERCENT PASSING HYDROMETER ANALYSIS TIME READINGS 45 MIN. 15 MIN ,^ 3" 5"6"_ 80 60 MIN. 19 MIN. 4 MIN. 1MIN. '200 '100 '50 '40'30 - ' 16 10'8 _ d 3/8'_ _ 314" +Y _ _. SIEVE ANALYSIS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 25 HP 7 HR 100 90 80 70 60 50 40. 30 20:... -10 20 30 -- 40 --; 50 10 0' 001 •70 80 90 002 005 .009 019 037 074 149 .297 .590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 12752200 0 42 DIAMETER OF PARTICLE IN MILLIMETERS SAND FINE I MEDIUM I COARSE FINE COARSE COBBLES CLAY (PLASTIC) TO SILT (NON -PLASTIC) GRAVEL PERCENT RETAINED • Sample of SAND, SILTY (SM ) From TH-1 AT 9 FEET GRAVEL 31 % SAND 50 SILT & CLAY 18 % LIQUID LIMIT PLASTICITY INDEX Sample of GRAVEL, CLAYEY (GC ) TP -1 AT 1 — 8 FEET From ra nin e72c-2933 GRAVEL 46 % SAND 18 SILT & CLAY 36 % LIQUID LIMIT % PLASTICITY INDEX % Gradation Test Results FIG. 10 PERCENT PASSING HYDROMETER ANALYSIS 25 HR 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4MIN. 1 MIN. '200 '100 '50'40'30 '16 '10'8 100.• SIEVE ANALYSIS U.S. STANDARD SERIES 90 70-- 60 50 40 30. 20'' 10 CLEAR SQUARE OPENINGS 318" 314' 11/2" 3" 5"6". 8 10 20 30 140 50 60 •70 -. 80 0 .001 .002 005 .009 019 .037 074 .149 .297 .590 0.42 DIAMETER OF PARTICLE IN MILLIMETERS 1.19 2.0 2.38 4.76 9.52 19.1 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND FINE MEDIUM ( COARSE GRAVEL 90 36.1 76.2 127 200 152 FINE 1 COARSE 1 COBBLES • • • 25 7 HR 45 MIN.15MIN 100 90 80 70 40• a 30 20 10 .. HYDROMETER ANALYSIS 1 TIME READINGS 60 MIN. 19 MIN. 4 MIN. 1 MIN. '• 200 "100 SIEVE ANALYSIS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS '4 318'_ 3/4" 11" 3' 5-6 80 '50 '40'30 '16 '10'8 0 .. .001 .002 .005 .009 .019 .037 074 .149 .297 O.d. 90 DIAMETER OF PARTICLE IN MILLIMETERS 10 20 30 .40 z 50 cl Z 60 70 80 . '-100 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 152 CLAY (PLASTIC) TO SILT (NON-PLASTICI SAND FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES Sample of SAND. CLAYEY (SC ) TH-3 AT 9 FEET From GRAVEL 34 % SAND 36 % SILT & CLAY 3 0 % LIQUID LIMIT % PLASTICITY INDEX % Sample of GRAVEL , CLAYEY ( GC ) From TP -2 AT 1 - 4 FEET GRAVEL 43 % SAND 21 % SILT & CLAY 36 % LIQUID LIMIT % PLASTICITY INDEX Gradation Test Results FIG. 11 HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40'30 '16 '10 "p. _. '_4... _ 3/8" 314" 1'/2"3" 5'6" 8" 100. /. 0 U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 90 17 a z 50. 40 30 10 0._ .001 .002 .005 .009 .019 .037 .074 .149 .297 .590 1.19 2.0 2.38 4.76 0.42 DIAMETER OF PARTICLE IN MILLIMETERS -10 20 30 9.52 19,1 36.1 0 60 70 80 r)90 ),100 76.2 76.2 127 200 152 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND FINE MEDIUM l COARSE GRAVEL FINE J COARSE 1 COBBLES PERCENT PASSING HYDROMETER ANALYSIS TIME READINGS 25 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 ' 100 '50 '40'30 ' 16 '10"8 100 • 90 SIEVE ANALYSIS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 3/8" 3/4" 11/2' 80 70 60 50 40 30 20 0 .001 .002 .005 009 019 037 .074 149 .297 .590 0.42 DIAMETER OF PARTICLE IN MILLIMETERS 5"6" 8" .0 10 .20 30 0 LI 40 X50 Z 60 •70 -80 90 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 152 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE MEDIUM i COARSE FINE COARSE COBBLES • • • Sample Of GRAVEL. CLAYEY (GC) GRAVEL 41 25 % SAND TP -3 AT 1 - 11 FEET From SILT& CLAY 34 % LIQUID LIMIT PLASTICITY INDEX Sample of GRAVEL , SILTY (GM ) From TH-6 AT 24 FEET �❑ „� r'c_'20-77 GRAVEL 41 % SAND 40 SILT & CLAY19 % LIQUID LIMIT PLASTICITY INDEX Gradation Test Results FIG. 12 PERCENT PASSING 45 MIN. 15 MIN 100 90 80 70 60 50 40 20 - 10 HYDROMETER ANALYSIS TIME READINGS 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 '50'40'30 '16 '10 '8 SIEVE ANALYSIS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 3/8" 314" 1Y/" 3" 5"6".80 0 001 .002 005 .009 .019 037 074 149 .297 .590 0.42 DIAMETER OF PARTICLE IN MILLIMETERS 1.19 2.0 2.38 4.76 10 20 30 40 Z 50 Z 60 70 80 --!90 '100 9.52 19.1 36.1 76.2 127 200 152 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE MEDIUM I COARSE FINE COARSE COBBLES • Sample of GRAVEL, SILTY (GM ) From TP -4 AT 1 - 12 FEET GRAVEL 54 % SAND 25 SILT & CLAY 21 % LIQUID LIMIT % PLASTICITY INDEX % HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40'30 '16 '10'8 100. U.S. STANDARD SERIES 90 80` 70 • vZ- 60' 50 _ . . LLg 40', CLEAR SQUARE OPENINGS 3/8' 314" 11/2" 3" 5"6" 80 10 20 •30 40 z •a- 50 • ;60 2 -,70 0 001 .002 .005 .009 .019 .037 .074 149 .297 .590 0.42 DIAMETER OF PARTICLE IN MILLIMETERS 1.19 2.0 2.38 4.76 9.52 19.1 36.1 80 90 '100 76.2 127 200 152 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE MEDIUM I COARSE FINE I COARSE ] COBBLES Sample of SAND, SILTY (SM ) From TH-7 AT 4 FEET GRAVEL 39 % SAND 45 % SILT&CLAY 16 % LIQUID LIMIT % PLASTICITY INDEX % Gradation Test Results FIG. 13 HYDROMETER ANALYSIS 25 HR 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40'30 '16 '10'8_ SIEVE ANALYSIS U.S. STANDARD SERIES 90 80 70 L7 60 w 40 30 20 10 0 001 CLEAR SQUARE OPENINGS 3/8' 314" 11/2" 3' 5"A' B_ 10 20 -; 30 --40 50 9, 60 70 80 90 '100 .002 .005 .009 .019 .037 .074 .149 .297 .590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 152200 0.42 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND FINE MEDIUM 1 COARSE GRAVEL FINE I COARSE 1 COBBLES HYDROMETER ANALYSIS 25 HR 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN 19 MIN. 4 MIN. 1 MIN '200 '100 '50 '40'30 '16 '10 ' 8 ' 4 318" 3/4' 11/2" 3" 5"6" 80 100 90 SIEVE ANALYSIS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 80 70 O y 60 Z 50 40 30 .- 20 10 0 001 002 .005 009 019 .037 .074 149 .297 .590 0.42 DIAMETER OF PARTICLE IN MILLIMETERS SAND FINE MEDIUM I COARSE CLAY (PLASTIC) TO SILT (NON -PLASTIC) ._ '100 9.52 19.1 36.1 76.2 127 200 152 GRAVEL FINE COARSE COBBLES PERCENT RETAINED • Sample of GRAVEL , SILTY (GM ) From TH-8 AT 4 FEET GRAVEL 46 % SAND 38 SILT & CLAY 16 LIQUID LIMIT PLASTICITY INDEX Sample of GRAVEL, SANDY (GP ) From TH-8 AT 9 FEET -7-,'.7^.77-7 GRAVEL 56 % SAND 35 SILT & CLAY 9 % UQUID LIMIT % PLASTICITY INDEX Gradation Test Results FIG. 14 O z m 0 w _1 CO o F- SUMMARY OF LABORATORY TEST RESULTS SOIL TYPE SAND, SILTY (SM) II CLAY, SANDY (CL) II CLAY, SANDY (CL) II GRAVEL, CLAYEY (GC) II SAND, CLAYEY (SC) II CLAY, SANDY (CL) CLAY, SANDY (CL) CLAY, SANDY (CL -ML) II GRAVEL, CLAYEY (GC) I SAND, CLAYEY (SC) CLAY, SANDY (CL) GRAVEL, CLAYEY (GC) PASSING NO. 200 SIEVE (%) W r am tD ("1 (.4 87 36 7 of V M SOLUBLE SULFATES (%) UNCONFINED COMPRESSIVE STRENGTH (psf) ATTERBERG LIMITS UW ^ I-po N Z 5� a t0 t0 CI F,. Q - e J N N N O O } r N C NATURAL DRY DENSITY (pcf) 0 e- O O r 107 I Q1 N r 104 1 41 r O O NATURAL MOISTURE ( %) M ID O 1 A- O at NCD O �, -, 10.3 1 N (0 CO N e- O M N h N CO e- In N T. C DEPTH BORING OR PIT (FEET) 0) a 0) CD e- 0) r a' Cr) er r `� e- 4.• e- r r = 1-- TH-2 r a E.- t7 = F- I'N = 1 2 1.... M Ea. Note: Swell due to wetting at an applied load of 1,000 psf. SUMMARY OF LABORATORY TEST RESULTS Note: Swell due to wetting at an applied load of 1,000 psf. SOIL TYPE CLAY, SANDY (CL) II CLAY, SANDY (CL) GRAVEL, SILTY (GM) 11 GRAVEL, SILTY (GM) II SAND, SILTY (SM) GRAVEL, SILTY (GM) I GRAVEL, SANDY (GP) 0o N N j \ N Q LL1 'O na.Z`�V In Q) r 1- N 01 1- (0 r Q) SOLUBLE SULFATES (%) UNCONFINED COMPRESSIVE STRENGTH (psf) ATTERBERG LIMITS PLASTICITY INDEX (%) o� a�^ J J SWELL' (%) O O NATURAL DRY DENSITY (pcf) 0 O .).- NATURAL MOISTURE (%) I.- h O N h In N '' O r' 9.5 I h ti N `") 1- O) 24 I N I... of V' CO BORING OR PIT tD H I H I A f" co H Note: Swell due to wetting at an applied load of 1,000 psf. o APPENDIX A • PAVEMENT DESIGN CALCULATIONS • MR. ART KLEINSTEIN CERISE RANCH CTUT GS•2933 • • • o o - o c h III r II lI ill , I (Isd ) W s nao 1N31TIS3a BIOS 038aV0a 3A 33333 ( SNO1111W ) B1M 'SNOIIV31"1ddV 00'01 31XV 319N 1N31VAIfO3 dlA-9I 1V101 031V1'4I1S -J 0 0 . 4,011 (%) a '1,111190'1132! h r 10 0 w z w cc - co z STRUCTURE z N w Cerise Ranch DESIGN CHART FOR FLEXIBLE PAVEMENT Job No. GS -2933 1 QESIGN SERVICEABILITY LOSS p PSI `� v n NNN O ",.. . ` o O 0 N o o - o c h III r II lI ill , I (Isd ) W s nao 1N31TIS3a BIOS 038aV0a 3A 33333 ( SNO1111W ) B1M 'SNOIIV31"1ddV 00'01 31XV 319N 1N31VAIfO3 dlA-9I 1V101 031V1'4I1S -J 0 0 . 4,011 (%) a '1,111190'1132! h r 10 0 w z w cc - co z STRUCTURE z N w Cerise Ranch DESIGN CHART FOR FLEXIBLE PAVEMENT Job No. GS -2933 • DESIGN CALCULATIONS GROUP 2 SOILS (Clay Subgrade) DESIGN DATA Equivalent Daily Load Application (EDLA) = 5 Hveem Stabilometer (R -Value) = 38 (from Fig. A-7 ) Structural Number (SN) = 2.2 (from Fig. A-2) DESIGN EQUATION SN = C,D, + C2D2 C, = 0.40 - Strength Coefficient - Asphalt Concrete C2 = 0.12 - Strength Coefficient - Aggregate Base Course D, - Depth of Asphalt Concrete (inches) • D2 - Depth of Aggregate Base Course (inches) FOR ASPHALT CONCRETE SECTION: D, = (2.2)/0.40 = 5.5 inches of Asphalt Concrete FOR ASPHALT + AGGREGATE BASE COURSE SECTION: D2 = ((2.2 ) - (3.0)(0.40))/0.12 = 8.33 inches of Aggregate Base Course with 3.0 inches of asphalt concrete RECOMMENDED SECTIONS: 1. 5.5 inches of Asphalt Concrete, or 2. 3.0 inches Asphalt Concrete + 8.0 inches Aggregate Base Course above a geotextile fabric. Fig. A-3 MR. ART KLEINSTEIN CERISE RANCH CM GS -2933 • PERCENT PASSING HYDROMETER ANALYSIS l SIEVE ANALYSIS 25 HR 7 HR TIME READINGS 45 MIN. 15 MIN 60 MIN 19 MIN. 4 MIN, 1 MIN. '200 '100 100 90 80 70 60 50 40 30 20 10 U.S. STANDARD SERIES '50 '40'30 '16 '10'8 CLEAR SQUARE OPENINGS '4 3/8" 314" 11/2" 3" 5"6" 8" 0 0 .001 .002 .005 .009 .019 .037 .074 149 .297 590 1.19 2.0 2.38 0.42 DIAMETER OF PARTICLE IN MILLIMETERS SAND CLAY (PLASTIC) TO SILT (NON -PLASTIC) TINE I MEDIUM I COARSE 4.76 9.52 19.1 36.1 10 20 30 40 50 60 70 80 90 100 76.2 127 200 152 GRAVEL FINE COARSE COBBLES PERCENT RETAINED Sample of SAND, SILTY (SM) GRAVEL 37 % SAND 47 From S-1 AT 1 - 4 FEET SILT&CLAY 16 % LIQUID LIMIT 21 PLASTICITY INDEX 3 % HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 100 90 80 70 N 60 z 50 U c-= 40 30 U.S. STANDARD SERIES '50 "40'30 '16 '10'8 CLEAR SQUARE OPENINGS '4 3/8' 314" 11/2" 3" 5"6" 8" 0 10 20 30 40 50 60 70 20 - 80 10 90 G 100 001 002 .005 .009 .019 .037 074 .149 .297 .590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 0.42 152 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE 1 MEDIUM 1 COARSE FINE I COARSE I COBBLES PERCENT RETAINED Sample of GRAVEL , SILTY ( GM ) GRAVEL 52 % SAND 23 From TP -5 AT 1 - 4 FEET SILT & CLAY 25 % LIQUID LIMIT 35 % PLASTICITY INDEX 10 JOB NO. GS -2933 Gradation Test Results FIG. A-4 • PERCENT PASSING HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HP. 7 HR TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN 4 MIN. 1 MIN '200 ''CO '50 '40' 30 '16 '10 ' 8 '4 3/8" 3/4" 11/2" 3" 5"6" 8' 100 / 0 90 80 70 60 50 40 30 20 10 10 20 30 40 Z 50 z 60 2 70 80 90 0 100 .001 .002 .005 009 .019 .037 074 .149 297 590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 0.42 152 DIAMETER OF PARTICLE IN MILLIMETERS SAND CLAY (PLASTIC) TO SILT (NON -PLASTIC) GRAVEL FINE l MEDIUM 1 COARSE FINE COARSE I COBBLES Sample of GRAVEL, SILTY (GM ) GRAVEL 56 % SAND 24 From S-3 AT 1 - 4 FEET SILT & CLAY 20 % LIQUID LIMIT 34 % PLASTICITY INDEX 7 HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. 7 HR TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 ' 100 '50 '40'30 '16 '10'8 '4 3/8" 3/4" 11" 3" 5'6" 80 100 90 10 80 20 70 U' 40 30 30 40 Z •a - W 50 60 2 70 20 80 10 90 0 100 .001 .002 .005 .009 .019 .037 .074 149 .297 .590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 0.42 152 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE MEDIUM 1 COARSE FINE 1 COARSE 1 COBBLES Sample of GRAVEL, CLAYEY ( GC ) From S-6 AT 1 - 4 FEET JOB NO. GS -2933 GRAVEL 27 % SAND 24 % SILT & CLAY 49 % LIQUID LIMIT 28 % PLASTICITY INDEX 11 % Gradation Test Results FIG. A-5 • • • PERCENT PASSING HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS 45 HR 7 HR 5 MIN 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN '200 ' 100 •50 '40'30 ' 16 '10'8 U.S. STANDARD SERIES 100 90 80 70 60 50 40 30 20 10 CLEAR SQUARE OPENINGS •4 3/8" 3/4" 1"2" 3" 5"6" 8" 0 10 20 30 40 50 60 70 80 90 0 100 001 002 005 009 .019 037 .074 149 .297 590 1 19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 0 42 152 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE MEDIUM ( COARSE EINE I COARSE COBBLES PERCENT RETAINED Sample of SAND, CLAYEY ( SC ) GRAVEL 30 % SAND 33 % From TP -6 AT 1 - 4 FEET SILT&CLAY 37 % LIQUID LIMIT 25 PLASTICITY INDEX 4 % PERCENT PASSING HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR 7 HR TIME READINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. •200 100 90 80 70 60 50 40 30 20 10 U.S. STANDARD SERIES '100 '50 '40'30 •16 '10'8 CLEAR SQUARE OPENINGS '4 3/8" 3/4" 11/2" 3" 5"6" 8" 0 0 001 002 005 009 019 037 074 .149 297 590 1.19 2.0 2.38 4.76 0.42 DIAMETER OF PARTICLE IN MILLIMETERS 9.52 19.1 36.1 10 20 30 40 50 60 70 80 90 100 76.2 127 200 152 CLAY (PLASTIC) TO SILT (NON -PLASTIC) SAND GRAVEL FINE MEDIUM I COARSE FINE l COARSE I COBBLES PERCENT RETAINED Sample of From GRAVEL, SANDY (GP) S-8 AT 1 - 4 FEET JOB NO. GS -2933 GRAVEL 74 % SAND 15 % SILT& CLAY_1 % LIQUID LIMIT 48 % PLASTICITY INDEX 18 Gradation Test Results FIG. A-6 • • EXUDATION PRESSURE (PSI) 900 800 700 600 500 400 300 200 100 k CI:2 1� + r Group Number t CLAY SUBGRA( AASHTO Classification A-4 Liquid Limit 29 Plasticity Index 7 Design R -Value 38 r I 1 I C i 1 1 I I r { 1 I t , 1 1 4 0 10 "R" VALUE Job No. GS -2933 20 30 40 50 60 70 80 Hveem Stabilometer Test Results 90 E) Fig. A-7 M 07 N 0 0 z 0 TABLE A- 1 SUMMARY OF LABORATORY TEST RESULTS DESCRIPTION SAND, SILTY CLAY, SANDY 11 GRAVEL, SILTY 11 GRAVEL, SILTY 11 CLAY, SANDY 11 CLAY, SANDY 11 GRAVEL, CLAYEY 11 1 SAND, CLAYEY 11 SAND, CLAYEY 11 GRAVEL, SILTY II } 0z a cn >. a J U NATURAL MOISTURE CONTENTS (%) •. UNIFIED SM CL 1 2 g 0 CL CL GC SC SC GM J J 0 AASHTO a a 'Ci T a A-4 A-4 co a A-4 1 a a I a GROUP INDEX 0 n 0 0 Ns 10 n 0 0 0 a LIQUID PLASTICITY LIMIT INDEX (%) (%) 0,n rn v r1 1 18 t� T N CO N )n C) c') a1 N 29 m N in N a) N4 1 48 a) N to T 87 1 25 20 1 82 77 a)i- M a) R T T cc N. GROUP NO. T N T T N N T T T T N SAMPLE DEPTH NO. (FEET) T T T T r T T T T T cti 01 T th N J> in F C') v� 'T cn In fD t �O F ^ w N Z 61 C E a • • • MR. ART KLEINSTEIN CERISE RANCH CTUT GS -2933 APPENDIX B PAVEMENT CONSTRUCTION RECOMMENDATIONS Eg • • • FLEXIBLE PAVEMENT CONSTRUCTION RECOMMENDATIONS Experience has shown that construction methods can have a significant effect on the life and serviceability of a pavement system. We recommend the proposed pavement be constructed in the following manner: 1. The subgrade should be stripped of organic matter, scarified, moisture treated, and compacted. Soils should be moisture treated to within 2 percent of optimum moisture content and compacted to at least 95 percent of maximum standard Proctor dry density (ASTM D 698, AASHTO T 99). The above moisture treatment and compaction recommendations also apply where additional fill is necessary. 2. Utility trenches and all subsequently placed fill should be properly compacted and tested prior to paving. As a minimum, fill should be compacted to 95 percent of ASTM D 698. 3. After final subgrade elevation has been reached and the subgrade compacted, the area should be proof -rolled with a heavy pneumatic - tired vehicle (i.e. a loaded ten -wheel dump truck). Subgrade that is pumping or deforming excessively should be scarified, moisture conditioned and compacted. 4. If areas of soft or wet subgrade are encountered, the material should be subexcavated and replaced with properly compacted structural backfill. Where extensively soft, yielding subgrade is encountered, we recommend the excavation be inspected by a representative of our office. 5. Aggregate base course should be laid in thin, loose lifts, moisture treated to within 2 percent of optimum moisture content, and compacted to at least 95 percent of maximum modified Proctor dry density (ASTM D 1557, AASHTO T 180). 6. Asphaltic concrete should be hot plant -mixed material compacted to at least 95 percent of maximum Marshall density. The temperature at laydown time should be near 235 degrees F. The maximum compacted lift should be 3.0 inches and joints should be staggered. 7. The subgrade preparation and the placement and compaction of all pavement material should be observed and tested. Compaction criteria should be met prior to the placement of the next paving lift. The additional requirements of the Colorado Department of Trans- portation Specifications should apply. MR. ART KLEINSTEIN CERISE RANCH CTLJT GS -2933 B-1 • • • MR. ART KLEINSTEIN CERISE RANCH ^T' T g_2o3g APPENDIX C PAVEMENT MAINTENANCE RECOMMENDATIONS EQ3 • • • MAINTENANCE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS The primary cause for deterioration of high traffic volume pavements is loss of integrity of the asphalt concrete and subgrade failure. High volumes also create pavement rutting and smooth, polished surfaces. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal and improving skid resistance through a new wearing course. 1. Annual Preventive Maintenance a. Visual pavement evaluations shall be performed each spring or fall. b. Reports documenting the progress of distress shall be kept current to provide information on effective times to apply preventive maintenance treatments. c. Crack sealing shall be performed annually as new cracks appear. 2. 3 to 5 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 3 to 5 years to reduce oxidative embrittlement problems. b. Typical preventive maintenance treatments include chip seals, fog seals, slurry seals and crack sealing. 3. 5 to 10 Year Corrective Maintenance a. Corrective maintenance may be necessary, as dictated by the pavement condition, to correct rutting, cracking and structurally failed areas. b. Corrective maintenance may include full depth patching, milling and overlays. c. In order for the pavement to provide a 20 year service life, at least one major corrective overlay can be expected. MR. ART KLEINSTEIN CERISE RANCH JT .S-2933 C-1 • • ri;;J March 26, 1998 Mr. Art Kleinstein c/o The Land Studio 123 Emma Road, Suite 204A Basalt, CO 81621 Attention: Ms. Julie Pratte Subject: Preliminary Geologic Hazard Evaluation and USDA Soil Conservation Service Data For Cerise Ranch Garfield & Eagle Counties, Colorado Job No. GS -2309 Gentlemen: This letter presents the results of our Preliminary Geologic Hazard Evaluation and a compilation of USDA Soil Conservation Service (SCS) data for Sketch Plan Submittal for the subject site. The following paragraphs describe geologic conditions and potential geologic hazards and discusses their possible influence on the planned development. A map indicating the approximate boundaries of SCS soil units and explanations are attached as Appendix A. Site Conditions Cerise Ranch is an approximately 300 acre parcel located in the Roaring Fork River Valley. The majority of the site is in Garfield County with a small portion at the east end being in Eagle County. Catherine Store is approximately 1 mile to the west. Highway 82 is along the south property boundary with the Roaring Fork River beyond to the south. The Dakota, Eagle Dakota and Soderberg Subdivisions are adjacent to the southeast, east and northeast, respectively. Agricultural land is on property to the west. Land to the north has not been built on. A residence and agricultural operation with several barns, sheds and outbuildings is located on the northwest part of the property. The Roaring Fork River Valley trends from the east, down to the west in the vicinity of the property. The site is situated on the north side of the valley floor and lower slopes of the valley sides. Ground surfaces drop steeply from the north down to the south on the valley sides, decreasing in steepness at the edge of the valley and flattening on the valley floor. A small pond is on the east part of the property. Several irrigation ditches cross the property from east to west. Vegetation on the valley floor and edges consists of irrigated pasture grasses and weeds. On the slopes above the valley, vegetation consists of pinion and juniper trees and sparse weeds and brush. CTL/THOMPSON, INC. CONSULTING ENGINEERS 234 CENTER DRIVE • GLENWOOD SPRINGS, COLORADO 81601 • (970) 945-2809 • • • Site Development At this writing development plans are conceptual. We understand the developer intends to develop the property for single family residential use. We anticipate infrastructure will include roadways and utilities. Buildings will likely be 1 or 2 story wood frame residences with or without basements. Geologic Setting In our opinion, no geologic conditions or potential geologic hazards exist that will preclude development of the site. The property is underlain by bedrock consisting of the Pennsylvanian aged Eagle Valley Evaporite. Bedrock is exposed on the slopes above the valley floor. Quaternary aged colluvial deposits overlay the bedrock and thicken on the lower slopes towards the edge of the valley floor forming a colluvial wedge. On the valley floor bedrock is covered with Quaternary aged terrace gravels deposited by the Roaring Fork River. Three alluvial fans coalesce along the north side of the valley floor covering the terrace gravels. A map of interpreted geologic units is shown on the Surficial Geologic Conditions Map, Figure 1. The Eagle Valley Evaporite consists of gypsum, anhidrite, halite and other evaporite minerals with interbedded siltstone and sandstone. The evaporite minerals have undergone plastic flow deformation due to overburden loading that has caused highly distorted and swirled bedrock orientation resulting in a highly varied heterogeneous geologic unit. Potential Geologic Hazards We identified several potential geologic hazards at the site that need to be considered when planning the development. Some of the geologic hazards can be mitigated by avoidance and others will need proactive mitigation. In our opinion, all of the potential geologic hazards can be mitigated using engineering and construction methods considered normal for this type of development in the locale. In our opinion, the geologic conditions and potential geologic hazards are similar to and no greater than those of other developments in the area (e.g. Aspen -Glen, River Valley Ranch, etc.). Conditions at this site are typical of mountainous terrain. Potential geologic hazards include ground subsidence (sink holes), debris/mud flows and potentially unstable slopes. Evidence of potential ground subsidence was observed in the east part of the property. Evaporite minerals in the underlying Eagle Valley Evaporite are prone to being dissolved and removed by circulating ground water forming "solution cavities". Overburden soils cave into the solution cavities. When caving propagates to the ground surface, a sink hole can form or an irregular rolling surface topography can develop. The presence of the evaporite minerals is random due to the highly variable nature of the geologic unit. We observed two well defined sink holes as well as areas of irregular surface topography in the subsidence area. In our opinion, the MR. ART KLEINSTEIN CERISE RANCH JOB NO. GS -2309 2 • • • subsidence mechanism is strongly influenced by historic flood irrigation of the property and the presence of a pond in one of the sinkholes. Development of the site with the proposed golf course and residential construction will eliminate flood irrigation and sprinkler irrigation will greatly reduce the amount of circulating ground water and, therefore, reduce ground subsidence. Although the degree of risk of damage to structures cannot be completely eliminated we believe that structures sited outside of the identified subsidence area will perform satisfactorily and are at no greater risk than structures in other developments in the area in a similar geologic environment. The two alluvial fans to the north are essentially dormant since their source basins have been pirated by the drainage feeding the southern most alluvial fan. The southern most alluvial fan appears to be an active geomorphic feature. Potential debris/mud flow hazards are associated with the southern most alluvial fan. Our field observations indicate that the debris fan presents a moderate potential hazard. In our opinion, the two alluvial fans to the north do not have source basins of sufficient size to result in a significant debris/mud flow hazard. Mitigation can be achieved by anticipating sediment loading 40 to 50 percent in developing the site drainage plan. Site drainage structures need to be designed such that blockage and overflow do not occur. If further quantification of the magnitude of potential debris flows is needed a drainage basin hydrologic analysis could be performed and included as part of the Preliminary Plan Submittal. A drain basin hydrologic analysis is beyond the scope of this report. The slopes in the north part of the property are steep. The slopes are underlain by the bedrock of the Eagle Valley Evaporite with a mantle of residual and colluvial soils. Excavation into slopes steeper than approximately 30 percent is likely feasible, however, the slopes should be considered potentially unstable. We did not observe any evidence of slope instability at the site. In our opinion, excavation into slopes steeper than 30 percent should be addressed by a geotechnical engineer on an individual basis. Potential geologic hazards are delineated on Figure 2. We appreciate the opportunity to work with you on this project. If you require any further service or have questions, please call. Very truly yours, CTL/THOMPSON, INC Wilson . Liv Professional Ge LB:JM:cd (3 copies sent) MR. ART KLEINSTEIN CERISE RANCH JOB NO. GS -2309 R ch ing, an h Manage 3 • • • MR. ART KLEINSTEIN CERISE RANCH JOB NO. GS -2309 APPENDIX A SCS DATA rg s • • CERISE RANCH GARFIELD & EAGLE COUNTIES, COLORADO Job No. GS -2309 SCS SOIL UNITS MAP Scale: 1w=1000' Fig. A-1 13—Atencio-Azeltine complex, 3 to 6 percent 0 apes. This map unit is on alluvial fans and terraces. 1 ne native vegetation is mainly grasses and shrubs. Elevation is 5,900 to 6,500 feet. The average annual precipitation is 15 to 18 inches, the average annual air temperature is 44 to 46 degrees F. and the average frost -free period is 105 to 120 days. This unit is about 60 percent Atencio sandy loam and 30 percent Azeltine gravelly sandy loam. Included in this unit are small areas of soils that are similar to the Atencio and Azeltine soils but are finer textured. Also included are small areas of gravel bars. Included areas make up about 10 percent of the total acreage. The Atencio soil is deep and well drained. It formed in alluvium derived dominantly from sandstone and shale. Typically, the surface layer is reddish gray sandy loam about 6 inches thick. The next layer is sandy loam about 4 inches thick. The subsoil is about 10 inches of sandy clay loam over about 4 inches of gravelly sandy loam. The upper 6 inches of the substratum is gravelly sandy loam. The lower part to a depth of 60 inches is very gravelly sand. The soil is noncalcareous to a depth of 20 inches and calcareous below that depth. In some areas the surface layer is gravelly or cobbly. Permeability is moderate to a depth of 30 inches in II'he Atencio soil and rapid below this depth. Available iter capacity is low. The effective rooting depth is 60 inches or more. Runoff is slow, and the hazard of water erosion is slight. The Azeltine soil is deep and well drained. It formed in alluvium derived dominantly from sandstone and shale. Typically, the surface layer is reddish gray gravelly sandy loam about 9 inches thick. The upper 7 inches of the substratum is gravelly loam. The lower part to a depth of 60 inches is extremely gravelly sand. The soil is calcareous throughout. In some areas the surface layer is cobbly loam or sandy loam. Permeability is rapid or very rapid below a depth of 16 inches in the Azeltine soil. Available water capacity is low. The effective rooting depth is 60 inches or more. Runoff is slow, and the hazard of water erosion is slight. This unit is used mainly for irrigated hay or pasture. It also is used for crops, urban development, wildlife habitat, or rangeland. If this unit is used for hay and pasture, the main limitations are the low available water capacity and small stones. Grasses and legumes grow well if adequate fertilizer is used. Good management helps to maintain optimum vigor and quality of forage plants. .Recause these soils are droughty, applications of .gation water should be light and frequent. Irrigation water can be applied by corrugation, sprinkler, and flooding methods. If properly managed, the unit can produce 4 tons of irrigated grass hay per acre annually. This unit is moderately well suited to irrigated crops. If furrow or corrugation irrigation systems are used, runs should be on the contour or across the slope. If properly managed, the unit can produce 70 bushels of barley per acre annually. The potential plant community on this unit is mainly western wheatgrass, Indian ricegrass, needleandthread, big sagebrush, and Douglas rabbitbrush. Nevada bluegrass, prairie junegrass, and bottlebrush squirreltail also are included. The average annual production of air- dry vegetation is about 800 pounds per acre. Suitable management practices include proper grazing use and a planned grazing system. If the quality of range vegetation has seriously deteriorated, seeding is needed. The main limitations are cobbles and stones. For successful seeding, a seedbed should be prepared and the seed drilled. Brush management improves deteriorated areas of range that are producing more woody shrubs than were present in the potential plant community. If this unit is used for homesite development, the main limitation is small stones. Population growth has resulted in increased construction of homes in areas of this unit. Topsoil can be stockpiled and used to reclaim areas disturbed during construction. The gravel and cobbles in disturbed areas should be removed if the site is landscaped, particularly in areas used for lawns. If the density of housing is moderate or high, community sewage systems are needed to prevent the contamination of water supplies resulting from seepage from onsite sewage disposal systems. This map unit is in capability subclass IVe, irrigated, and Vle, nonirrigated. It is in the Rolling Loam range site. 38—Evanston loam, 1 to 6 percent slopes. This deep, well drained soil is on alluvial fans, terraces, and valley sides. It formed in alluvium derived dominantly from material of mixed mineralogy. Elevation is 6,500 to 8,000 feet. The average annual precipitation is 13 to 15 inches, the average annual air temperature is 42 to 46 degrees F, and the average frost -free period is 80 to 90 days. Typically, the surface layer is brown loam about 14 inches thick. The subsoil is clay loam about 17 inches thick. The substratum to a depth of 60 inches or more is loam. Included in this unit are small areas of Tridell, Uracca, and Forelle soils. Also included are small areas of soils that are similar to the Evanston soil but have more stones. Included areas make up about 15 percent of the total acreage. Permeability is moderate in the Evanston soil. 0 Available water capacity is high. The effective rooting epth is 60 inches or more. Runoff is slow, and the nazard of water erosion is slight. This unit is used mainly as rangeland. It also is used for pasture, crops, or wildlife habitat. A few areas also are used for homesite development. The potential plant community on this unit is mainly bluebunch wheatgrass, western wheatgrass, muttongrass, Douglas rabbitbrush, and mountain big sagebrush. Utah serviceberry, mountain snowberry, prairie junegrass, and Ross sedge commonly are also included. The average annual production of air-dry vegetation is about 1,500 pounds per acre. If the range condition deteriorates, mountain big sagebrush, Douglas rabbitbrush, cheatgrass, and annual weeds increase in abundance. Suitable management practices include proper grazing use and a planned grazing system. Brush management improves deteriorated areas of range that are producing more woody shrubs than were present in the potential plant community. This soil responds well to applications of fertilizer, to range seeding, and to proper grazing use. If the quality of range vegetation has seriously deteriorated, seeding is needed. This unit is well suited to hay and pasture. It has few lelimitations. A seedbed should be prepared on the ontour or across the slope where practical. Applications of nitrogen and phosphorus fertilizer improve growth of forage plants. If properly managed, the unit can produce 5 tons of irrigated grass hay per acre annually. This unit is well suited to irrigated crops. If properly managed, it can produce 90 bushels of barley per acre annually. This unit is suited to homesite development. The main limitation is the shrink -swell potential. The effects of shrinking and swelling can be minimized by prewetting foundation areas. Population growth has resulted in increased construction of homes in areas of this unit. This map unit is in capability subclass IVe, irrigated and nonirrigated. It is in the Deep Loam range site. 55—Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes. This map unit is on mountainsides, on hills, and along dissected drainageways (fig. 5). It is on hills and canyon side slopes throughout the survey area. This unit is about 65 percent Gypsum land and 20 oercent Gypsiorthids. Included in this unit are small areas of Torriorthents and Camborthids. Included areas make up about 15 percent of the total acreage. The Gypsum land consists mainly of exposed parent material that has a very high content of gypsum. The Gypsiorthids are shallow and moderately deep and well drained. They formed in residuum and colluvium derived dominantly from mixed material with a very high content of gypsum. Slope is 12 to 50 percent. No single profile of these soils is typical, but one commonly observed in the survey area has a surface layer of very pale brown fine sandy loam about 8 inches thick. The substratum is fine sandy loam. Soft, gypsiferous shale is at a depth of about 39 inches. Permeability is moderate in the Gypsiorthids. Available water capacity is low or moderate. The effective rooting depth is 10 to 40 inches. Runoff is very rapid, and the hazard of water erosion is slight to severe on the steeper slopes. This unit is used as wildlife habitat. The native vegetation on the Gypsiorthids is sparse grasses, forbs, and Utah juniper. The Gypsum land supports very little native vegetation. This unit is poorly suited to homesite development. The main limitations are the slope, the hazard of erosion, piping, and low soil strength during wet periods. This map unit is in capability class VIII. No range site is assigned. 69—Kilgore silt loam. This deep, poorly drained soil is on alluvial valley floors, flood plains, low terraces, and alluvial fans. It formed in alluvium derived dominantly from mixed sources. Elevation is 6,000 to 9,800 feet. The average annual precipitation is 18 to 20 inches, the average annual air temperature is 38 to 40 degrees F, and the average frost -free period is 70 to 95 days. Typically, the surface layer is very dark grayish brown silt loam about 4 inches thick. The upper 21 inches of the substratum is silt loam. The next 4 inches is very gravelly sandy loam. The lower part to a depth of 60 inches is very gravelly loamy sand. Included in this unit are small areas of Atencio, Azeltine, Showalter, Morval, and Empedrado soils. Included areas make up about 10 percent of the total acreage. Permeability is moderately slow in the Kilgore soil. Available water capacity is low. The effective rooting depth is 60 inches or more. Runoff is slow, and the hazard of water erosion is slight or moderate on the steeper slopes. A high water table is at a depth of 1 to 3 feet. The soil is occasionally flooded for very brief periods in spring and summer. •This unit is used as hayland, pasture, or rangeland. It well suited to hay and pasture. Wetness limits the choice of suitable forage plants and the period of cutting or grazing and increases the risk of winterkill. Grazing when the soil is wet results in compaction of the surface layer, poor titth, and excessive runoff. Applications of nitrogen fertilizer improve the growth of forage plants. If properly managed, the unit can produce 3.5 tons of irrigated grass hay per acre annually. The potential plant community on this unit is mainly tufted hairgrass, Nebraska sedge, slender wheatgrass, ovalhead sedge, and willow. Other plants that characterize this site are western yarrow, Rocky Mountain iris, and shrubby cinquefoil. The average annual production of air-dry vegetation is about 3,000 pounds per acre. If the range condition deteriorates, willow, iris, and shrubby cinquefoil increase in abundance. If the condition of the range further deteriorates, Kentucky bluegrass and Canada thistle increase in abundance. This unit is poorly suited to homesite development. The main limitations are seepage, the wetness, the frost action potential, and the flooding. A drainage system is needed if roads and building foundations are iikonstructed. This map unit is in capability subclass Vw, irrigated and nonirrigated. It is in the Mountain Meadow range site. 106—Tridell-Brownsto stony sandy loams, 12 to 50 percent slopes, extremely stony. This map unit is on terraces and mountainsides. Elevation is 6,400 to 7,700 feet. The average annual precipitation is 12 to 14 inches, the average annual air temperature is 42 to 44 degrees F, and the average frost -free period is 85 to 105 days. This unit is about 45 percent Tridell soil and 35 percent Brownsto soil. About 5 to 10 percent of the surface is covered with stones. Included in this unit are small areas of Forelle and Evanston soils in the less sloping cleared areas. Also included are small areas of basalt Rock outcrop and soils that are similar to the Tridell soil but have less gravel and fewer stones. Included areas make up about 20 percent of the total acreage. • The Tridell soil is deep and somewhat excessively drained. It formed in alluvium and colluvium derived dominantly from sandstone and basalt. Typically, the upper part of the surface layer is grayish brown stony sandy loam about 2 inches thick. The lower part is grayish brown very cobbly fine sandy loam about 7 inches thick. The upper 5 inches of the substratum is very cobbly fine sandy loam. The next part is cobbly sandy loam about 11 inches thick. Below this is 12 inches of very stony fine sandy loam. The lower part of the substratum to a depth of 60 inches is very stony loamy sand. Hard basalt is commonly below a depth of about 60 inches. The soil is calcareous throughout. A thin layer of partially decomposed needles, twigs, and leaves is on the surface in many places. Permeability is moderately rapid in the Tridell soil. Available water capacity is low. The effective rooting depth is 60 inches or more. Runoff is rapid, and the hazard of water erosion is moderate. The Brownsto soil is deep and well drained. It formed in alluvium derived dominantly from coarse textured, calcareous sandstone and basalt. Typically, the upper part of the surface layer is Tight brownish gray stony sandy loam about 4 inches thick. The lower part is light brownish gray stony sandy loam about 7 inches thick. The upper 19 inches of the substratum is very gravelly sandy loam. The next 12 inches is very gravelly loamy sand. The lower part to a depth of 60 inches is gravelly construction. The gravel and cobbles in disturbed areas should be removed if the site is landscaped, particularly in areas used for lawns. Areas adjacent to hillsides are occasionally affected by runoff, which may be accompanied by the movement of rock debris. Population growth has resulted in increased construction of homes in areas of this unit. This map unit is in capability subclass Vile, nonirrigated. The Tridell soil is in the Pinyon -Juniper woodland site, and the Brownsto soil is in the Stony Foothills range site. 114—Yamo loam, 1 to 6 percent slopes. This deep, 0 111 drained soil is on fans and toe slopes. It formed in .,olluvium derived dominantly from sandstone, shale, and gypsum. Elevation is 6,200 to 7,500 feet. The average annual precipitation is 10 to 14 inches, the average annual air temperature is 40 to 44 degrees F, and the average frost -free period is 85 to 105 days. Typically, the surface layer is light brownish gray loam about 8 inches thick. The subsoil is loam about 6 inches thick. The substratum to a depth of 60 inches or more is loam. Thin strata of material that ranges from gravelly clay loam to sand are common below a depth of 40 inches. Included in this unit are small areas of Forelle and Mussel soils and areas of Gypsiorthids. Also included are small areas of soils that are similar to the Yamo soil but have a more alkaline subsoil and support greasewood vegetation. Included areas make up about 20 percent of the total acreage. Permeability is moderate in the Yamo soil. Available water capacity is high. The effective rooting depth is 60 inches or more. Runoff is slow, and the hazard of water erosion is slight. This unit is used mainly for rangeland, hay, pasture, or irrigated crops. It also is used for homesite development. 0The potential plant community on this unit is mainly astern wheatgrass, bluebunch wheatgrass, Indian ricegrass, prairie junegrass, Wyoming big sagebrush, and Douglas rabbitbrush. Other plants that characterize this site are needleandthread, bottlebrush squirreltail, and Sandberg bluegrass. The average annual production of air-dry vegetation is about 800 pounds per acre. If the range condition deteriorates, Wyoming big sagebrush, Douglas rabbitbrush, cheatgrass, and annual weeds increase in abundance. If the quality of range vegetation has seriously deteriorated, seeding is needed. The plants selected for seeding should meet the seasonal requirements of livestock, wildlife, or both. For successful seeding, a seedbed should be prepared and the seed drilled. This unit is well suited to hay and pasture. Proper grazing practices, weed control, and fertilizer are needed to ensure maximum quality of forage. Irrigation water can be applied by corrugation and sprinkler methods. Leveling helps to ensure the uniform application of water. In some places sinkholes or pipes may develop because of the content of gypsum in the soil. If properly managed, the unit can produce 4 tons of irrigated grass hay per acre annually. • This unit is well suited to irrigated crops. It is limited mainly by content of gypsum and the susceptibility to piping and sinkholes. Sprinkler irrigation can be used, but water should be applied slowly to minimize runoff. Pipe, ditch lining, or drop structures in irrigation ditches facilitate irrigation and help to control erosion. Returning crop residue to the soil or regularly adding other organic material improves fertility, reduces crusting, and increases the water intake rate. Crops respond well to applications of nitrogen and phosphorus fertilizer. Crops suitable for this soil include alfalfa and small grains. This unit is suited to homesite development. The shrink -swell potential is a limitation. It can be minimized by prewetting the foundation area. Areas adjacent to hillsides are occasionally affected by runoff, which may be accompanied by the movement of rock debris. Population growth has resulted in increased • construction of homes in areas of this soil. This map unit is in capability subclass IVe, irrigated and nonirrigated. It is in the Rolling Loam range site. 115—Yamo loam, 6 to 12 percent slopes. This deep, well drained soil is on fans and toe slopes. It formed in colluvium derived dominantly from sandstone, shale, and gypsum. Elevation is 6,200 to 7,500 feet. The average annual precipitation is 10 to 14 inches, the average annual air temperature is 40 to 44 degrees F, and the average frost -free period is 85 to 105 days. Typically, the surface layer is light brownish gray loam about 8 inches thick. The subsoil is loam about 6 inches thick. The substratum to a depth of 60 inches or more is loam. Thin strata of material that ranges from gravelly clay loam to sand are common below a depth of 40 inches. Included in this unit are small areas of Forelle and Mussel soils and small areas of Gypsiorthids. Also included are small areas of soils that are similar to the Yamo soil but have a more alkaline subsoil and support some greasewood vegetation. Included areas make up about 20 percent of the total acreage. Permeability is moderate in the Yamo soil. Available water capacity is high. The effective rooting depth is 60 inches or more. Runoff is medium, and the hazard of water erosion is slight. This unit is used mainly as rangeland, hayland, or pasture. It also is used for homesite development. The potential plant community on this unit is mainly western wheatgrass, bluebunch wheatgrass, Indian ricegrass, prairie junegrass, Wyoming big sagebrush, and Douglas rabbitbrush. Other plants that characterize this site are needleandthread, bottlebrush squirreltail, and Sandberg bluegrass. The average annual production of air-dry vegetation is about 800 pounds per •re. If the range condition deteriorates, Wyoming big .,agebrush, Douglas rabbitbrush, cheatgrass. and annual weeds increase in abundance. Range seeding may be needed if the range is in poor condition. For successful seeding, a seedbed should be prepared and the seed drilled. The plants selected for seeding should meet the seasonal requirements of livestock, wildlife, or both. This unit is suited to homesite development. The main limitation is the slope in the steeper areas. The shrink -swell potential is also a limitation. It can be minimized by prewetting the foundation area. Areas adjacent to hillsides are occasionally affected by runoff, which may be accompanied by the movement of rock debris. This map unit is in capability subclass IVe, irrigated and nonirrigated. It is in the Rolling Loam range site. • • 111/1 (Some terms that describe restrictive soil features are defined in the Glossary. See text for definitions of "good," "fair," and other terms. Absence of an entry indicates that the soil was not rated. The information in this table indicates the dominant soil condition but does not eliminate the need for onsite investigation) TABLE 12.--CONSTRUCT[ON MATERIALS Soil name and map symbol Roadfill Sand Gravel Topsoil Rock outcrop. 13*: 1 1 Atencio Good (Probable (Probable Poor: I I small stones, 1 I area reclaim. Azeltine (Good (Probable Probable Poor: I I too sandy, I I small stones, I I area reclaim. 38 Good (Improbable: Improbable: Good. Evanston 1 1 excess fines. excess fines. 55*: 1 1 I Gypsum land. 1 1 I I I I Gypsiorthids Poor: lImprobable: Improbable: (Poor: I area reclaim, 1 excess fines. excess fines. 1 area reclaim, 111/1 Islope. I I slope. 1 I I I 1 1 I 69 Fair: (Probable (Probable Poor: Kilgore 1 wetness. 1 1 1 small stones, I I I area reclaim. 1 I I Rock outcrop. 1 1 I • 106*: 1 1 I Tridell (Poor: lImprobable: lImprobable: Poor: I slope. 1 excess fines. 1 excess fines. 1 small stones, I I slope. Brownsto (Poor: lImprobable: lImprobable: (Poor: I slope. 1 excess fines. 1 excess fines. 1 small stones, I I area reclaim, I I slope. 114, 115 Yamo Good Improbable: lImprobable: (Poor: excess fines. 1 excess fines. 1 small stones. * See description of the map unit for composition and behavior characteristics of the map unit. s TABLE 14. --ENGINEERING INDEX PROPERTIES (The symbol < means less than; > means more than. Absence of an entry indicates that data were not estimated) Soil name and map symbol 1 IDepth1 I I 1 Rock outcrop. 13*: Atencio • • Azeltine 38, 39 Evanston Classification IFrag- I USDA texture I I Invents I 1 Unified I AASHTO Percentage passing sieve number -- I> 3 I 1 1 'inches' 4 I 10 I 40 200 I i (Liquid 1 Plas- I limit 1 ticity I I index 1 1 i I I 1 0-101Sandy loam ISM 10-241Gravelly sandy ISC I clay loam, sandyl I clay loam, 1 gravelly sandy 1 1 loam. 24-301Gravelly sandy 1 clay loam, I gravelly sandy I loam. 30-60IExtremely cobbly I sand, very 1 gravelly sand. 0-9 'Gravelly sandy I loam. 9-16IGravelly sandy I loam, gravelly I loam. 16-601Extremely I gravelly sand. 0-141Loam 14-311Loam, 31-60ILoam I I I 1 I I I I I I I IA -2 0-5 175-100175-100150-65 IA -2, A-6 0-5 165-90 150-90 135-65 ISM -SC, IA -2 I GM -GC 1 1 1 I 1 ISP, GP, IA -1 I SP -SM, 1 I GP -GM 1 1 ISM, SM-SC,IA-2, I GM, GM -GCI IGM-GC, IA -2, 1 SM -SC, I A-6 1 GC, SC I IGP IA -1 1 I 1 IML IA -4 IA -6 1A-4 clay loam ICL ICL -ML I 55*: 1 1 I Gypsum land. 1 I 1 1 Gypsiorthids----1 0-8 'Fine sandy loam IML, SM, IA -4, A-2 0-5 I 1 CL -ML, 1 I 1 SM -SC 1 18-23IFine sandy loam, IML, SM, IA -4, A-2 0-5 1 loam. 1 CL -ML, I 1 I SM -SC 1 123-39IFine sandy loam, IML, SM 1A-4, A-2 1 loam. I I 139 'Weathered bedrockl --- 1 --- 69 1 0-4 'Silt loam ICL IA -6 Kilgore 1 4-25ISilt loam, loam, ICL -ML, CL IA -6, A-4 I clay loam. 1 I 125-29IVery gravelly ISM, GM IA -1 I sandy loam, veryl I gravelly coarse 1 1 sandy loam. 1 I 129-60IVery gravelly IGP, GP-GM,IA-1 1 loamy sand, veryl GM, SP I 1 gravelly sand. 1 1 1 1 1 1 1 5-10 150-80 150-75 140-65 20-60 1 1 1 A-4 1 0-5 160-85 150-75 140-65 25-40 20-30 I I 1 1 I A-4,1 0-5 160-85 150-75 140-65 25-50 25-35 I 1 1 1 I I 1 1 1 I 115-30 125-40 120-35 110-20 1 0-5 I 1 I 1 I I I 1 1 I I 0 195-100195-100170-85 150-70 0 195-100195-100170-90 150-70 I 0 195-100195-100165-85 150-60 1 1 100 190-100150-90 100 190-100150-90 20-30 15-20 25-45 20-30 15-30 15-25 1 I I 1 I 1 1 1 I I 140-60 135-55 110-35 1 0-10 1 1 I I I I I See footnote at end of table. 1 0-5 1 100 190-100150-80 1 0 195-100190-95 175-90 70-80 30-35 10-15 0 95-100185-95 175-90 70-80 25-40 5-20 I I 1 10-15 50-60 130-45 120-30 10-20 15-20 NP -5 I I I 1 I I I 1 1 I 10-30 35-55 130-50 115-35 1 0-15 NP 30-35 25-35 20-30 NP -5 10-15 5-10 NP NP -10 5-15 NP 5-10 10-15 5-10 25-65 20-35 1 NP -10 25-60 20-35 1 NP -10 15-60 20-35 1 NP -10 • • TABLE 14. --ENGINEERING INDEX PROPERTIES --Continued I I Classification IFrag- 1 Percentage passing 1 1 Soil name and IDepthl USDA texture 1 Iments 1 sieve number-- ILiquid 1 Plae- Unified 1 AASHTO 1> 3 1 1 1 limit 1 ticity map symbol I I )inches) 4 10 40 1 200 1 1 index Rock outcrop. 106*: Tridell Brownsto 0-2 2-37 37-60 0-11 11-30 30-60 Stony sandy loam CL -ML, I SM -SC Very cobbly fine IGM, GM -GC sandy loam, extremely gravelly sandy 1 loam, very stony) fine sandy loam. Very gravelly IGP sand, extremely 1 gravelly sand, 1 extremely cobblyl sand. Stony sandy loam IGM-GC, I SM -SC Very gravelly IGM sandy loam, very) cobbly sandy loam. Very gravelly IGM, SM, loamy sand, 1 GP -GM, gravelly sandy 1 SP -SM loam, very gravelly sandy loam. 1 1 1 1 A-4, A-2 120-30 75-95 170-90 60-80 130-60 20-30 5-10 I 1 A-1, A-2 135-50 145-55 140-50 30-40 115-30 15-30 NP -10 I I I 1 1 I 1 1 I 1 A-1 130-45 35-45 30-40 20-30 1 0-5 NP 1 I I I 1 I I I I I I I I I I I 1 I I A-4, A-2 130-45 160-70 155-65 45-55 125-45 25-30 5-10 I 1 A-1 115-35 50-60 45-55 25-35 115-25 NP 1 I I 1 I I I A-1 110-20 50-65 45-60 25-35 10-20 NP 1 I I I I I I I 1 1 I I 1 I 1 114, 115, 116----1 0-8 (Loam IML, CL -ML IA -4 1 0 180-100175-100160-90 150-65 115-25 NP -10 Yamo 1 8-14ILoam, clay loam ICL -ML, CL IA -4, A-6 1 0 180-100175-100160-90 150-75 1 20-30 5-15 114-601Loam, clay loam ICL -ML, CL IA -4, A-6 I 0-5 180-100175-100160-90 150-75 1 20-30 5-15 i 1 I I ----I. 1 I 1 1 * See description of the map unit for composition and behavior characteristics of the map unit. • • CS -2309 FIG.1 3/25/98 CO • • :3. 3 Q 0. - fl O �p :3 Q_ Q Q -0 0 X. Q N 0 0 n 0 0 0 cD 0 n — C0 Z o �0 O c 3Q Q lD O Q 3 Q Q O (`] 0 N o 0 C £ Q 0 C3 -, 3 3 Q Q UD io!Ardo patio c Pzi n D r dYW SNOI110N00 01001030 uaninnipoo pa6o pe6D ,(aouaa}onp spanoa6 aoDJIal. ass 2 • CS -2509 WI 3/25,/98 Cb • • U Cr C C - ` N C z 0 N ' z- 5--13 'O N a CQ a Oµ D n Fi' CD 0 a mCro 0 C Q • m m Q O 0 <. N. < X O m • 3 -ao o m m `13 tQ m ▪ Q CD N O O Q o"a t0 1 . o z C 3 m Q POTENTIAL GEOLOGIC HAZARDS 0 rm 0 {d\ 00V210100 'S311N1l00 310V3 saaols algo}sun ,(IID!{ua{od Potential subsidence nazard area *�7 1 °r` i yr. GIYIID couterr LADLE S `Y,14 '1 0