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Home My WebLink About20051947.tiff EEC July 30, 2002 EARTH ENGINEERING Mn Bob Parsons CONSULTANTS, INC. 40455 Skylark Drive Fort Collins, Colorado 80524 Re: Geologic Evaluation Peace Haven Estates Weld County, Colorado EEC Project No. 1022125 Mr. Parsons: Earth Engineering Consultants, Inc. (EEC)personnel have completed the geologic evaluation you requested for the referenced project. That evaluation was completed by reviewing readily available data concerning soil and groundwater conditions at the site, principally through review of United States Geologic Society(USGS)/Colorado Geologic Society(CGS) and Department of Agriculture Soil Conservation Service (SCS)published information. A listing of the references reviewed as a part of the geologic hazard study is included with this report. We understand the lots at the referenced project will be at least 5 acres in size, therefore no percolation testing was completed as a part of this evaluation. The Peace Haven Estates project is located in Section 10, T7N, R67W of the 6(h P.M. in Weld County, Colorado. The development parcel includes approximately 48.5 acres. Site drainage is to the southeast with total elevation change across the site on the order of 30 feet.A diagram indicating the approximate location of the development is included with this report. The attached soil classification map includes demarcation of those soil groupings identified on the site by SCS soil maps. SCS descriptions of those soil types are provided with this report. In general, the near surface soils at this site appear to be a blend of low plasticity clay loam and fine sandy loam soils. The SCS information indicates the property would be expected to have groundwater at depths of 5 to 20 feet. According to the geologic maps of the area, the surficial materials mapped consist of eolean(wind deposited) soils from the Upper Holocene and Pleistocene geologic period. The eolean materials overlie the Upper Transition Member of the Pierre Shale bedrock formation. The Upper Transition Member consists of sandstone with sandy shale layers. According to SCS data, depth to bedrock in CENTRE FOR ADVANCED TECHNOLOGY 2301 RESEARCH BOULEVARD, SUITE 104 FORT COLLINS, COLORADO 80526 (970) 224-1522 (FAx) 224-4564 2005-1947 Earth Engineering Consultants,Inc. EEC Project No. 1022125 July 30, 2002 Page 2 the Olney series is greater than 60 inches; however, bedrock in the Renohill series could be encountered between 20 and 40 inches below present site grades. Based on our review of the site as outlined above, we expect the near surface soils could be used for support of lightly loaded residential structures. The near surface soils appear to exhibit a low potential for volume change with variation in moisture content; however, the Renohill series may exhibit moderate to high swell potential. SCS information indicates the Olney series would be expected to exhibit acceptable percolation rates for on-site septic systems; however, the Renohill series may exhibit slow percolation rates or shallow bedrock. During our review of available site data, we did not identify potential geologic hazards as outlined in H.B. 1041. Shallow bedrock and slower percolation rates would be expected in the area of the Renohill Series. In addition, we did not identify economically recoverable mineral resources as defined in H.B. 1041 at this site. The evaluation for this report was based on a review of readily available public information for the property. Specific site data should be developed for individual residences and septic fields once the locations of those improvements are identified. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information or require additional information, please do not hesitate to contact us. Very truly yours, Ear ,.r.'.sT•.eering Consultants, Inc. i° 4 REtt .. O 1.1 C( 1 /'• . CS C----- •C'. Mic' :'' : 'oley, P.E. Project Engineer WELD COUNTY ROAD 84 SUBJECT -'/PROPERTY 47 \. 57 \ 48 34 1/ 4 57 NOT TO SCALE SCS SOIL SERIES MAP PEACE HAVEN ESTATES - WELD COUNTY, COLORADO PROJECT NO: 1022125 DATE: JULY 2002 47—Olney fine sandy loam, 1 to 3 percent slopes. This is a deep, well drained soil on plains at elevations of ble years to 1,800 pounds in unfavorable years. As range 4,600 to 5,200 feet. It formed in mixed outwash deposits. condition deteriorates, the sand bluestem, sand reedgrass, Included in mapping are small areas of soils that have a and switchgrass decrease and blue grams, sand dropseed, dark surface layer. Some small leveled areas are also in- and sand sage increase. Annual weeds and grasses invade eluded the site as range condition becomes poorer. Typically the surface layer of this Olney soil is grayish Management of vegetation on this soil should be based brown fine sandy loam about 10 inches thick. The subsoil on taking half and leaving half of the total annual produc- is yellowish brown and very pale brown sandy clay loam tion. Seeding is desirable if the range is in poor condition. about 14 inches thick. The substratum to a depth of 60 Sand bluestem, sand reedgrass, switchgrass, sideoats inches is very pale brown,calcareous fine sandy loam. grams, blue grams, and pubescent wheatgrass are suite- Permeability and available water capacity are ble for seeding. The grass selected should meet the moderate. The effective rooting depth is 60 inches or seasonal requirements of livestock. It can be seeded into more. Surface runoff is medium, and the erosion hazard is a clean, firm sorghum stubble, or it can be drilled into a low. firm prepared seedbed. Seeding early in spring has In litigated areas this soil is suited to all crops corn- proven most successful. monly grown in the area, including corn, sugar beets, Windbreaks and environmental plantings are generally beans, alfalfa, small grain, potatoes, and onions. An exam- suited to this soil. Soil blowing, the principal hazard in ple of a suitable copping system is 3 to 4 years of alfalfa establishing trees and shrubs, can be controlled by cul- followed by corn, corn for silage, sugar beets, small grain, tivating only in the tree row and by leaving a strip of or beans. Land leveling, ditch lining, and installing vegetation between the rows. Supplemental irrigation pipelines may be needed for proper water application. All may be needed at the time of planting and during dry methods of irrigation are suitable, but furrow irrigation is periods.Trees that are best suited and have good survival the most common. Barnyard manure and commercial fer- are Rocky Mountain juniper, eastern redcedar, ponderosa Wien-are needed for top yields. pine, Siberian elm, Russian-olive, and hackberry. The In nonirrigated areas this soil is suited to winter wheat, shrubs best suited are skunkbush sumac, lilac, and Siberi- barley, and sorghum. Most of the acreage is planted to an peashrub. winter wheat. The predicted average yield is 28 bushels Wildlife is an important secondary use of this soil. The per acre. The soil is summer followed in alternate years cropland areas provide favorable habitat for ring-necked to allow moisture accumulation. Generally precipitation is pheasant and mourning dove. Many nongame species can too low for beneficial use of fertilizer. be attracted by establishing areas for nesting and escape Stubble mulch farming, striperopping, and minimum dl- cover. For pheasants, undisturbed nesting cover is essen- lage are needed to control soil blowing and water erosion. tial and should be included in plans for habitat develop- Terracing also may be needed to control water erosion. went, especially in areas of intensive agriculture. Range- The potential native vegetation on this range site is land wildlife, for example, the pronghorn antelope, can be dominated by sand bluestem, sand reedgrass, and blue attracted by developing livestock watering facilities, grams Needleandthread, switchgrass, sideoats grama, managing livestock grazing, and reseeding where needed and western wheatgrass are also prominent. Potential Rapid expansion of Greeley and the surrounding area production ranges from 2,200 pounds per acre in favora- has resulted in urbanization of much of the Olney soil 4 This soil has good potential for urban and recreational development. The only limiting feature is the moderately rapid permeability in the substratum, which causes a hazard of ground water contamination from sewage lagoons. Lawns, shrubs, and trees grow well. Capability subrlac5 IIe irrigated, We nonirrigated; Sandy Plains range site. USDA SOIL CONSERVATION SERVICE SOIL GROUP DESCRIPTION OLNEY SERIES Forth Fnainpprinn rnncnitnntc 48—Olney fine sandy loam, 3 to 5 percent slopes. This is a deep, well drained soil on plains at elevations of 4,600 to 5,200 feet. It formed in mixed outwash deposits. Windbreaks and environmental plantings are generally Included in mapping are small areas of soils that have a suited to this soiL Soil blowing, the principal hazard in dark surface layer and small areas of soils that have establishing trees and shrubs, can be controlled by cul- sandstone and shale within a depth of 60 inches. tivating only in the tree row and by leaving a strip of Typically the surface layer of this Olney soil is grayish vegetation between the rows. Supplemental irrigation brown fine sandy clay loam about 8 inches thick. The sub- may be needed at the time of planting and during dry soil is yellowish brown and very pale brown fine sandy periods. Trees that are best suited and have good survival loam about 12 inches thick The substratum to a depth of are Rocky Mountain juniper, eastern redcedar, ponderosa 60 inches is very pale brown, calcareous fine sandy loam. pine, Siberian elm, Russian-olive, and hackberry. The Permeability and available water capacity are shrubs best suited are skunkbush sumac, War and Siberi- moderate. The effective rooting depth is 60 inches or an peashrub. more. Surface runoff is medium, and the erosion hazard is Wildlife is an important secondary use of this soil The low. cropland areas provide favorable habitat for ring-necked In irrigated areas this soil is suited to the crops corn- pheasant and mourning dove. Many nongame species can monly grown in the area. Perennial grasses and alfalfa or be attracted by establishing areas for nesting and escape close grown crops should be grown at least 50 percent of cover. For pheasants, undisturbed nesting cover is essen- the time. Contour ditches and corrugations can be used in tial and should be included in plans for habitat develop- irrigating close grown crops and pasture. Furrows, con- went, especially in areas of intensive agriculture. Range- tour furrows, and cross slope furrows are suitable for row land wildlife, for example, the pronghorn antelope, can be crops. Sprinkler irrigation is also desirable. Keeping til- attracted by developing livestock watering facilities, lege to a minimum and utilizing,crop residue help to con- managing livestock grazing, and reseeding where needed. trol erosion. Maintaining fertility is important. Crops Rapid expansion of Greeley and the surrounding area respond to applications of phosphorus and nitrogen. has resulted in urbanization of much of this Olney soil. In nonirrigated areas this soil is suited to winter wheat, The soil has good potential for urban and recreational barley, and sorghum. Most of the acreage is planted to development The only limiting feature is the moderately winter wheat. The predicted average yield is 25 bushels rapid permeability in the substratum, which causes a per acre. The soil is summer fallowed in alternate years hazard of ground water contamination from sewage to allow moisture accumulation. Generally precipitation is lagoons. Lawns, shrubs, and trees grow well. Capability too low for beneficial use of fertilizer. subclass IIIe irrigated, IVe nonirrigated; Sandy Plains Stubble mulch fanning, striperopping, and minimum til- range site. lage are needed to control soil blowing and water erosion. Terracing also may be needed to control water erosion. The potential native vegetation on this range site is dominated by sand bluestem, sand reedgrass„and blue grams. Needleandthread, switchgrass, sideoats grams, and western wheatgrass are also prominent Potential production ranges from 2,200 pounds per acre in favora- ble years to 1,800 pounds in unfavorable years. As condi- tion deteriorates, sand bluestem, sand reedgrass, and switchgrass decrease and blue grams, sand dropseed, and sand sage increase. Annual weeds and grasses invade the site as range condition becomes poorer. Management of vegetation on this soil should be based on taking half and leaving half of the total annual produc- tion. Seeding is desirable if the range is in poor condition. Sand bluestem, sand reedgrass, switchgrass, sideoats grams, blue grams, pubescent wheatgrass, and crested wheatgrass are suitable for seeding. The grass selected should meet the seasonal requirements of livestock. It can be seeded into a clean, firm sorghum stubble, or it can be drilled into a firm prepared seedbed. Seeding early in spring has proven most successfuL USDA SOIL CONSERVATION SERVICE SOIL GROUP DESCRIPTION OLNEY SERIES Earth Engineering Consultants 57—Renohill clay loam, 3 to 9 percent slopes. This is a moderately deep, well drained soil on upland hills and Closely spaced contour ditches can be used in irrigating ridges at elevations of 4,850 to 5,200 feet it formed in close grown crops. Contour furrows should be used for residuum from shale. Included in mapping are small areas row crops. Applications of barnyard manure and commer- . of soils that have shale deeper than 40 inches. vial fertilizer help to maintain good production. Keeping Typically the surface layer is grayish brown clay loam tillage to a minimum and utilizing crop residue are impor- about 9 inches thick. The subsoil is grayish brown and tant. pale brown clay loam about 12 inches thick. The sub- The potential native vegetation is dominated by stratum is pale brown clay loam. Shale is at a depth of western wheatgrass and blue grams. Buffalograss is also about 29 inches. present Potential production ranges from 1,000 pounds Permeability is slow. Available water capacity is per acre in favorable years to 600 pounds in unfavorable moderate. The effective rooting depth is 20 to 40 inches. years. As range condition deteriorates, a blue grams-buf- Surface runoff is medium to rapid, and the erosion hazard falograss sod forms. Undesirable weeds and annuals in- is moderate. vade the site as range condition becomes poorer. This soil is suited to limited cropping. Intensive Management of vegetation on this soil should be based cropping is hazardous because of erosion.- The cropping on taking half and leaving half of the total annual produc- system should be limited to such close grown crops as al- tion. Range pitting can reduce runoff.Seeding is desirable Calla, wheat, and barley. The soil also is suited to fir- if the range is in poor condition. Western wheatgrass, rigated pasture. A suitable cropping system is 3 to 4 blue grama, sideoats grams, buffalograss, pubescent years of alfalfa followed by 2 years of corn and small wheatgrass, and crested wheatgrass are suitable for seed- grain and alfalfa seeded with a nurse crop. ing. The grass selected should meet the seasonal require- ments of livestock It can be seeded into a clean, firm sorghum stubble, or it can be drilled into a firm prepared seedbed. Seeding early in spring has proven most success- ful. Windbreaks and environmental plantings are generally not suited to this soil. Onsite investigation is needed to determine if plantings are feasible. Supplemental water is needed for successful plantings. Wildlife is an important secondary use of this soil. The cropland areas provide favorable habitat for ring-necked pheasant and mourning dove. Many nongame species can be attracted by establishing areas for nesting and escape cover. For pheasants, undisturbed nesting cover is essen- tial and should be included in plans for habitat develop- ment, especially in areas of intensive agriculture. Range- land wildlife, for example, the pronghorn antelope, can be attracted by developing livestock watering facilities, managing livestock grazing,and reseeding where needed. This soil has poor potential for urban and recreational development. The chief limiting features are the underly- ing shale, the low strength, and the moderate to high shrink swell. These features present severe problems in dwelling and road construction and in use of septic tank absorption fields and sewage lagoons. Capability subclass IVe irrigated, Vie nonirrigated;Clayey Plains range site. USDA SOIL CONSERVATION SERVICE SOIL GROUP DESCRIPTION RENOHILL SERIES REFERENCES 1. Colton R.B. and Harold R. Fitch, 1974, Map Showing Potential Sources of Gravel and Crushed-Rock Aggregate, in the Boulder-Fort Collins-Greeley Area. Front Range Urban Corridor, Colorado: U.S. Geological Survey Miscellaneous Investigation Series Map I-855-D. 2. Colton R.B., Holligan, J.A., and Anderson, L.W., 1975, Preliminary Map of Landslide Deposits, Greeley 1°x2° Quadranele, Colorado: U.S. Geological Survey Miscellaneous Investigation Series Map MF-704. 3. McCain, J. and Hotchkiss, W.R., 1975, Map Showing Flood-Prone Areas, Boulder- Fort Collins-Greeley Area,Front Range Urban Corridor, Colorado: U.S. Geological Survey Miscellaneous Investigation Series Map I-855-E. 4. Colton R.B., 1978, Geologic Map of the Boulder-Fort Collins-Greeley Area, Colorado: U.S. Geological Survey Miscellaneous Investigation Series Map I-955-G. 5. Hershey L.A. and Schneider, Jr. P.A., 1972, Geologic Map of the Lower Cache La Poudre River Basin.North-Central Colorado: U.S. Geological Survey Miscellaneous Investigation Series Map I-687. 6. Hillier D. and Schneider,Jr. P.A., 1979, Depth to the Water Table in the Boulder-Fort Collins-Greeley Area, Front Range Urban Corridor. Colorado: U.S. Geological Survey Miscellaneous Investigation Series Map I-855-I. 7. United States Department of Agriculture Soil Conservation Service and Forest Service in Cooperation with Colorado Agricultural Experiment Station, 1980, Soil Survey of Weld County Area, Colorado, Maps 239-812/3. Hello