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HomeMy WebLinkAboutFALCON RIDGE PUD - PRELIMINARY - 2-94F - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTThe Thedalund series consists of moderately deep, well drained soils that formed in material weathered from sandstone and shale. These soils are on uplands and are underlain by soft sandstone and shale at a depth of 20 to 40 inches. Elevation ranges from 4,800 to 5,600 feet. Slopes are 0 to 9 percent. The native vegetation is blue grama, buffalograss, sage, and cactus. glean annual precipitation ranges from 13 to 15 inches, mean annual air temperature ranges from 48' to 501 F, and the frost -free season ranges from 135 to 150 days. In a representative profile the surface layer is gray- ish brown loam about 6 inches thick. The subsurface layer is light olive brown loam 8 inches thick. The underlying material is light yellowish brown loam about 23 inches thick over soft shale and sandstone. Permeability is moderate, and the available water capacity is medium. Reaction is neutral above a depth of about 6 inches, mildly alkaline between depths of 6 and 14 inches, and moderately alkaline below a depth of 14 inches. These soils are used mainly for native grasses and dryfarmed crops. A few areas are used for irrigated drops. Representative profile of Thedalund loam, 3 to 9 percent slopes, in native grass, 1,150 feet east and 1,400 feet south of the northwest corner of sec. 33, T. 11 N., R. 68 W.: A1-0 to 6 inches; grayish brown (10YR 5/2) loam, dark brown (10YR 4/2) moist; weak medium and fine granular struc- ture; soft, friable; neutral; clear smooth boundary. AC-6 to 14 inches; light olive brown (2.5Y 5/4) loam, olive brown (2.5Y 4/4) moist; massive; slightly hard, friable; calcare- ous; mildly alkaline; clear smooth boundary. C1-14 to 37 inches; light yellowish brown (2.5Y 6/4) loam, light olive brown (2.5Y 5/4) moist; massive; hard, very friable; cal- careous; moderately alkaline; clear smooth boundary. C2r-37 to 60 inches; light gray (2.5Y 7/2) dry and moist interbedded shale and sand- stone. The Al horizon is loam or light clay. loam 4 to 11 inches thick. The C horizon is loam or light clay loam. Depth to calcareous material ranges from 0 to 6 inches. Reaction ranges from neutral to moderately alkaline. Content of rock fragments ranges from 0 to 15 percent throughout, but particularly in the surface layer. 107—Thedalund loam, 0 to 3 percent slopes. This nearly level soil is on uplands. This soil has a profile similar to the one described as representative of the series, but the surface layer is about 8 inches thick. Included with this soil in mapping are some small areas of soils that are more sloping and a few small areas of Kim soils. Runoff is slight, and the hazard of erosion is slight to moderate. If irrigated, this soil is suited to barley, wheat, and corn and, to a lesser extent, alfalfa and sugar beets. Under dryland management it is suited to wheat and barley. It is also well suited to pasture and native grasses. Capability units IIIe-3, irrigated, and IVe-3, dryland; Loamy Plains range site; windbreak suit- ability group 1. 108—Thedalund loam, 3 to 9 percent slopes. This gently sloping to moderately sloping soil is on uplands. This soil has the profile described as representative of the series. Included with this soil in mapping are a few small areas of soils that are more sloping or less sloping. Also included are a few small areas of soils that have a surface layer of clay loam and small areas of Kim, Cushman, and Midway soils. Runoff is medium, and the hazard of erosion is mod- erate. If irrigated, this soil is suited to barley, wheat, alfalfa, and pasture. Under dryland management it is suited to pasture or native grasses. Capability units IVe-1, irrigated, and VIe-1, dryland; Loamy- Plains range site; windbreak suitability group 1. SCS Soil Survey — Thedalund Series (108) FALCON RIDGE DEVELOPMENT Fort Collins, Colorado PROJECT Nn! 1942016 Drawn: LLL Scale: None The Kim series consists of deep, we' ained soils that formed in mixed alluvium. These soils are on fans and benches. Elevation ranges from 4,800 to 5,600 feet. Slopes are 0 to 15 percent. The native vegetation is mainly blue grama, western wheatgrass, and some forbs. Nfean annual precipitation ranges from 13 to 15 inches, mean annual air temperature ranges from 481 to 50' F, and the frost -free season ranges from 135 to 150 days. In a representative profile the surface layer is light yellowish brown loam about 7 inches thick. The under- lying material is pale yellow and light yellowish brown loam about 53 inches thick. Permeability is moderate, and the available water capacity is high. Reaction is mildly alkaline above a depth of 7 inches and moderately alkaline below that depth. These soils are used mainly for irrigated and dry - farmed crops and for pasture and native grasses. Representative profile of Kim loam, 5 to 9 percent slopes, in a cultivated area, about 100 feet west and 40 feet north of the southeast corner of the NE1/4 sec. 36, T. 8 N., R. 69 W.: Ap-0 to 7 inches; light yellowish brown (2.5Y 6/3) loam, olive brown (2.5Y 4/3) moist; moderate fine and very fine gran- ular structure; soft, very friable; cal- careous; mildly alkaline; clear smooth boundary. C1-7 to 13 inches; pale yellow (2.5Y 7/3) loam, olive brown (2.5Y 4/3) moist; weak me- dium prismatic structure parting to weak medium subangular blocky; hard, friable; calcareous; moderately alkaline; gradual smooth boundary. C2-13 to 40 inches; pale yellow (2.5Y 7/3) loam, olive brown (2.5Y 4/4) moist; massive; slightly hard, very friable; calcareous; moderately alkaline; clear smooth boundary. C3-40 to 60 inches; light yellowish brown (2.5Y 6/3) loam, olive brown (2.5Y 4/3) moist; massive; slightly hard, very fri- able; calcareous; moderately alkaline. The A horizon is fine sandy loam, loam, or light clay loam 5 to 12 inches thick. The C horizon is loam or light clay loam. It is calcareous but lacks a zone of lime accumulation in most profiles. Sandstone bedrock is below a depth of 40 inches in some profiles. 53—Kim loam, 1 to 3 percent slopes. This nearly level soil is on uplands and fans. This soil has a profile similar to the one described as representative of the series, but the surface layer is about 12 inches thick. Included with this soil in mapping are a few small areas of soils that are more sloping or less sloping, a few small areas of soils that have a surface layer of clay loam, and a few small areas of soils that have gravel on the surface. Also included are a few small areas of Fort Collins and Stoneham soils. A water table is within the root zone for part of the growing season in a few areas. Runoff is slow. The hazard of water erosion is slight, and the hazard of wind erosion is moderate. If irrigated, this soil is suited to corn, sugar beets, beans, wheat, barley, and alfalfa. Under dryland man- agement it is suited to pasture or native grasses and, to a lesser extent, wheat and barley. Capability units Ile-1, irrigated, and IVe-3, dryland; Loamy Plains range site; windbreak suitability group 1. 54—Kim loam, 3 , 5 percent slopes. This gently sloping soil is on uplands and fans. This soil has a profile similar to the one described as representative of the series, but the surface layer is about 10 inches thick. Included with this soil in mapping are small areas of soils that are more sloping or less sloping and small areas of soils that have a surface layer of clay loam. A water table is within the root zone during the grow- ing season in a few small areas. Also included are a few small areas of Fort Collins, Stoneham, and Theda- lund soils. Runoff is medium, and the hazard of erosion is mod- erate. If irrigated, this soil is suited to barley, alfalfa, and wheat and, to a lesser extent, corn and beans. Under dryland management it is suited to pasture and native grasses. Capability units IIIe-2, irrigated, and IVe-3, dryland; Loamy Plains range site; windbreak suit- ability group 1. 55—Kim loam, 5 to 9 percent slopes. This strongly sloping soil is on uplands and fans. This soil has the profile described as representative of the series. Included with this soil in mapping are small areas of soils that have a surface layer and subsoil of clav loam or silt loam and a few small areas of soils that have gravel on the surface. Also included are minor areas of Stoneham and Thedalund soils. Runoff is rapid, and the hazard of erosion is severe. If irrigated, this soil is well suited to pasture and, to a lesser extent, barley, alfalfa, and wheat. Under dry - land management it is suited to pasture and native grasses. Capability units IVe-1, irrigated, and VIe-1, dryland; Loamy Plains range site; windbreak suit- ability group 1. 56—Kim-Thedalund loams, 3 to 15 percent slopes. This complex consists of gently sloping to moderately steep soils on uplands, fans, and valleysides. It is about 45 percent Kim loam and about 35 percent Thedalund loam. Kim loam is smoother and less sloping, and Thedalund loam is steeper. These soils have profiles similar to the ones described as representative of their respective series, but the surface layer is about 4 or 5 inches thick. Included with these soils in mapping are a few small areas of Renohill and Midway soils, a few small out- crops and gravel knobs, and some small seep spots. Runoff is rapid, and the hazard of erosion is severe. These soils are mainly used for pasture and native grasses. Capability unit VIe-1, dryland; Loamy Plains range site; windbreak suitability group 1. SCS Soil Survey - Kim Series (54) FALCON RIDGE DEVELOPMENT Fort Collins, Colorado Drawn: LLL Scale: None PROJECT No: 1942016 Earth Engineering Arl Pak ;4' 04, A Ir sow Falcon Ridge Df j 7", 'V Nl < SCS Soil Survey Map FALCON RIDGE DEVELOPMENT Fort Collins, Colorado Drawn: LLL Scale: None PROJECT No: 1942016 sneering tonsu Earth Engineering Consultants, Inc. Falcon Ridge Development Preliminary Geotechnical Evaluation March 28, 1994 Page 3 below grade areas if basements will be constructed. Raising of the finish floor elevations of the houses constructed in this area could also be considered. At other locations on the site it does not appear as though shallow groundwater will be a concern. The preliminary analysis and recommendations presented in this report are based on field observations of the test pit excavations at the indicated locations and from any other information discussed in this report. This report does not reflect any variations which may occur between the excavations or across the site. The information provided in this preliminary evaluation should be verified by a complete geotechnical exploration prior to developing final plans for this project. This report has been prepared for the exclusive use of Sherman Homes, Ltd. for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. We appreciate the opportunity to be of service to you on this project. If you have any questions regarding this preliminary information, or if we can be of further service to you in any other way, please do not hesitate to contact us. Very truly yours, Consultants, Inc. Principal Engineer Reviewed by: l L5 n, P.E. vir"ineer cc: Stewart and Associates; Attn: Mr. Dick Rutherford Faith F.nginmmg CmsuUnnts, Inc. Falcon Ridge Development Preliminary Geotechnical Evaluation March 28, 1994 Page 2 Regarding the test pit observations, the subsurface materials encountered at this site generally consisted of sandy silty clay which was underlain at varying depths by apparent sandstone bedrock. The near surface soils have low plasticity and should not be subject to large volume changes with normal fluctuations in moisture content. The sandstone is essentially non -expansive. However, the sandstone bedrock appeared to be well cemented and was difficult to excavate with the backhoe. During the test pit excavations, free water was encountered in the test pits excavated in the northeast portion of the site. In this area, groundwater was encountered at depths of approximately 5 to 7 feet. Longer term observation would be necessary to more accurately evaluate groundwater levels and fluctuation. PRELIMINARY EVALUATION Based on our field observations and review of available published data concerning this site, it is our opinion the subsurface conditions at the site would not be restrictive to the proposed development. The near surface soils appear to have low expansion potential. Consequently, we would expect conventional footing foundations could be used for building support. The near surface soils could also be used for support of the floor slabs and pavements. Shallow bedrock was encountered in some areas of the site. Excavation of these materials could be difficult for both construction of foundations and installation of underground utilities. In some areas, blasting of the bedrock may be necessary to allow construction of the improvements. Foundations could likely be supported directly on the bedrock. In the northeast corner of the site, shallow groundwater was observed in the test pits. Use of an underdrain system may be required in this area for reducing potential for water seepage in March 29, 1994 Sandcreek Associates 2002 Rollingwood Drive Fort Collins, CO 80525 Attn: Mr. Pete Sherman Re: Preliminary Geotechnical Evaluation Falcon Ridge Development Country Club Road and Ford Lane Fort Collins, Colorado EEC Project No. 1942016 Mr. Sherman: i0 P li- �A EARTH ENGINEERING CONSULTANTS, INC. We have completed the preliminary geotechnical evaluation you requested for the referenced project. Results of that evaluation are presented in this report. We understand the proposed Falcon Ridge Development will be constructed on an approximate 20 acre parcel located south of Country Club Road and west of Ford Lane in an area to be annexed by the City of Fort Collins. The Falcon Ridge Development is intended to be constructed as single family housing involving primarily one or two story wood frame buildings containing full basements. Infrastructure improvements including water, sewer and streets will be required for the development. Small cuts and fills are expected to develop site grades on the property. To develop preliminary information on the site, a senior project engineer from Earth Engineering Consultants, Inc. (EEC) reviewed published information concerning soils and geologic conditions in this area and observed the excavation of test pits completed at selected locations. The soils and geologic information reviewed included Soil Conservation Service mapping of expected surficial soils and Colorado Geologic Society mapping of anticipated geology in this area. A copy of the Soil Conservation Service surface soils map for this site and the associated written descriptions of the soil profiles for identified soil types are included with this report. 2600 Canton Ct, Suite A Fort Collins, CO 80525 (303) 224-1522 FAX 224-4564