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16 • SOIL SURVEY •
<br />Slope and excessive shrinking and swelling upon
<br />wetting and drying are the moat limiting soil properties
<br />to be considered in the design of recreation and homesite
<br />developments. Snow removal becomes an increasingly
<br />greater problem ae more homes aze built. Slope stabiliza-
<br />tion ie difficult even where homes aze constructed on
<br />nearly level pads. Surface runoff resulting from snowmelt
<br />increases the erosion hazard on cut and fill elopes. Seed-
<br />ing of vegetation minimizes the erosion hazard, but
<br />establishing a stand is difficult. Homes should be
<br />designed to utilize existing slope and keep foundation cuts
<br />to a minimum. Roads should be designed to keep cute and
<br />fills to a minimum and provide drainage outlets for exces-
<br />sive snowmelt. All-weather asphalt roads and normal
<br />foundations aze impractical unless provisions are made to
<br />offset the shrink-swell and frost action.
<br />Woodland wildlife includes mule deer, elk, blue grouse,
<br />snowshoe hare, yellow-bellied marmot and chipmunks.
<br />The natural migration of deer and elk herds has been
<br />disturbed in many azeas now used for recreation homesite
<br />subdivisions. Capability subclass VIIe.
<br />15-Placer diggings. These are areas of gravel, cob-
<br />bles, and stones, left as spoil from dredging operations on
<br />the valley floor. They aze along Blue River, French
<br />Creek, and Swan River. These areas support practically
<br />no vegetation. They are valuable as a source of coazse ag-
<br />gregate for use in construction. Capability class VIII.
<br />16C-Quander cobbly loam, 0 to 6 percent slopes.
<br />This is a deep, well drained, nearly level to gently sloping
<br />soil on terraces. It formed in glacial drift derived from a
<br />variety of rocks. The average annual precipitation is
<br />about 18 inches, the average annual air temperature is
<br />about 37 degrees F, and the frost-free season is 30 to 75
<br />days. Elevation is 7,500 to 9,500 feet.
<br />Small areas of Handran, Leavitt, and Youga soils are
<br />included in mapping. Also, a small area west of Green
<br />Mountain Reservoir has sandstone bedrock at a depth of
<br />20 to 40 inches.
<br />Typically, the surface layer is dark grayish brown
<br />cobbly loam about 10 inches thick. The subsoil is brown
<br />very cobbly sandy clay loam about 49 inches thick. The
<br />substratum is yellowish brown very eobbly sandy clay
<br />loam to a depth of 60 inches or more.
<br />Permeability is moderate, and the available water
<br />capacity is moderate, Surface runoff is slow. The hazard
<br />of wind and water erosion is slight.
<br />Most of the acreage is rangeland that is also used for
<br />recreation and wildlife. A cold climate and a short grow-
<br />ing season limit the production of introduced grasses and
<br />preclude use of this soil as cropland.
<br />Management of this soil for range should include a
<br />deferred grazing system and brush control. Grasses
<br />recommended for seeding include western wheatgraas,
<br />slender wheatgraas, bluebunch wheatgraas, mountain
<br />brome, Arizona fescue, and big bluegrass. The dominant
<br />native vegetation consists of Junegrase, wheatgraas,
<br />fescue, serviceberry, antelope bitterbruah, big sagebrush,
<br />and numerous forbs. The total annual production averages
<br />about 1,700 pounds of sirdry forage per acre.
<br />Large and small atones in the profile are the moat
<br />limiting soil properties to be considered in the design of
<br />access roads and recreation homesite subdivisions. Ex-
<br />cavation is difficult because of stones in the profile. AIl-
<br />weather asphalt surfaces are impractical unless provisions
<br />are made to offset frost action.
<br />Rangeland wildlife includes mule deer, sage grouse,
<br />white-tailed jackrabbit, mourning dove, ground squirrels,
<br />and yellow-bellied marmot. Capability subclass VIe.
<br />16D-Quander cobbly loam, 6 to 15 percent elopes.
<br />This is a deep, well drained, moderately sloping to
<br />strongly sloping soil on fans and mountainsides. It formed
<br />in glacial drift derived from a variety of rocks. The
<br />average annual precipitation is about 18 inches, the
<br />average annual air temperature is about 37 degrees F,
<br />and the frost-free season is 30 to 75 days. Elevation is
<br />7,500 to 9,500 feet.
<br />Small azeas of Handran, Leavitt, and Youga soils are
<br />included in mapping. A few small areas northeast of Sil-
<br />verthorne have shale bedrock at a depth of 30 to 45
<br />inches, and a small area west of Green Mountain Reser-
<br />voir has sandstone bedrock at 20 to 40 inches.
<br />Typically, the surface layer ie dark grayish brown
<br />cobbly loam about 10 inches thick. The subsoil is brown
<br />very cobbly sandy clay loam about 49 inches thick. The
<br />substratum is yellowish brown very cobbly sandy loam to
<br />a depth of 60 inches or more.
<br />Permeability is moderate, and the available water
<br />capacity is moderate. Surface runoff ie medium. The
<br />hazazd of wind erosion is slight, and the hazard of water
<br />erosion is moderate.
<br />Most of the acreage is rangeland that ie also used for
<br />recreation and wildlife. A cold climate and a short grow-
<br />ing season limit the production of introduced grasses and
<br />preclude use of this soil as cropland.
<br />Management of this soil for range should include a
<br />deferred grazing system and brush control. Grasses
<br />recommended for seeding include western wheatgraas,
<br />slender wheatgraas, bluebunch wheatgraas, mountain
<br />brome, Arizona fescue, and big bluegrass. The dominant
<br />native vegetation consists of Junegrass, wheatgraas,
<br />fescue, aerviceberry, antelope bitterbruah, big sagebrush,
<br />and numerous forbs. The total annual production averages
<br />about 1,700 pounds of av-dry forage per acre.
<br />Slope and excessive small ar large atones are the moat
<br />limiting soil properties to be considered in the design of
<br />access roads and recreation homesite subdivisions. Slope
<br />stabilization is difficult even where homes are constructed
<br />on nearly level pads. Seeding of vegetation minimizes the
<br />erosion hazard, but establishing a stand is difficult. Stones
<br />in the soil profile interfere with excavation and cuts and
<br />fills. Homes should be designed to utilize existing slope
<br />and keep foundation cute to a minimum. Roads should be
<br />designed to keep cut and fill slopes to a minimum. All-
<br />weather asphalt surfaces are impractical unless provisions
<br />are made to offset frost action.
<br />Rangeland wildlife includes mule deer, sage grouse,
<br />white-tailed jackrabbit, mourning dove, ground squirrels,
<br />and yellow-bellied marmot. Capability subclass VIe.
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