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i
<br />IVnndhrnd a ilrll~/r, ;u e birds ;urd m;unnutls nl' t~'ooded
<br />areas, either h:u du•nod nr cmtifemus trees and shrubs,
<br />or a mixture of both. Examples are blue grouse, band-
<br />tailed pigeon, thrush. vireo, woodpeckers. snowshoe
<br />hare, bobcat, mule deer, elk, and black bear.
<br />li'rlhnul ,~ ilrlr/r, are birds ant ,n;tn,mals of s~~:unp)•,
<br />m:ushv, nr open-t:ater areas. Examples are ducks,
<br />grew, hermt~, shore birds, rails, kin;; fishers. muskrat,
<br />mink, beaver, and rnccnmt.
<br />Engineering '
<br />This section is useful to those tyho need information
<br />about soils used as structural material or as foundation
<br />upmt which structures are built Among those who can
<br />benefit from this section are planning cotmnissions,
<br />town and city managers, land developers, engineers,
<br />contractm•s, and farmers.
<br />Among properties of soils highly important in
<br />engineering are permeability, strength, compaction
<br />characteristics, drainage cnnrlition, shrink-svcll poten-
<br />tial, grain size, plasticity, and reaction. Also important
<br />are depth to the vyater table, depth to bedrock, and
<br />slope. These properties, in various degrees and combina-
<br />tions, affect construction and nutintenance of roads,
<br />airpos•ts, pipelines, frnnulations for small buildings,
<br />in'igation systems, ponds and small dams. and systems
<br />for disposal of sewage and refuse.
<br />
<br />Pnn,pefnnd trildli/e are birds at
<br />rmtgelnnd. Examples are antelo
<br />scalcrl quail, grouse, meadovvltu•k
<br />Information in this section of the soil survey can be
<br />helpful to those who-
<br />1. Select potential residential, industrial, cannuer-
<br />cial, and recreational areas.
<br />°. Evaluate alternate routes for roads, high,vays.
<br />pipelines, and undergroatd cables.
<br />3. Seek sources of gravel, sand, or clay.
<br />4. Plan farm drainage systems, irrigation sys-
<br />tems, ponds, terraces, and other structures for
<br />controlling.eater and conserving soil.
<br />5. Correlate performance of shuctures already
<br />built with properties of the kinds of soil on
<br />which they are built, for the purpose of pre-
<br />dicting performance of structures on the some
<br />or similar Icinds oC soil in other Incations.
<br />G. Predict the lrafhcability of soils fm crnss-
<br />country movement of vehicles and construction
<br />equipment.
<br />7. Uevelnp preliminary estimates pertinent to
<br />construction in a p:u ticul;u• area.
<br />]Host of the information in this section is presented
<br />in tables G, 7, and S, which shuts, respectively, esti-
<br />mates of soil properties significant in engineering;
<br />engineering interpretations; and engineering test data.
<br />~ I''LA YIO P.. GONZA LES, cngi ncc r, Soil Cnnscrya Ilan Scrvicc,
<br />helped prepare this sodion.
<br />This information, along with the soil map and other
<br />parts of this publication, can he user! to make interpre-
<br />tatimts in adrlitimt to those given in tables fi and 7, and
<br />it also can be used to make other useful maps.
<br />This information, however, does not eliminate need
<br />for further investigations at sites selected for engineer-
<br />ing works, especially works that invoice heavy loads
<br />or that require excavations to depths greater than
<br />those shown in the tables, generally depths more than
<br />G feet. A{so, inspection of sites, especially the small
<br />ones, is needed because many delineated areas of a given
<br />soil mapping uniC may contain small areas of other
<br />kinds of soil that have strongly contrasting properties
<br />and different suitabilities or limitatimts for soil engi-
<br />neering.
<br />Some of the terms used in this soil survey have
<br />special meaning in soil science that ma}• not be fami-
<br />liar to engineers. The Glossary defines many terms
<br />commonly' used in soil science.
<br />Engineering clnssificrrt inn .t VStern!
<br />The ttvo systems most commonly used in classifying f
<br />samples of soils for engineering are the Unified system
<br />(2) used by the SCS engineers and others and the
<br />AASHTO system (/) adopted by the American Asso-
<br />~~ cratton of State Htghwa} and Ttansportatiat Officials
<br />In the~Jnified system soils
<br />particle-size distribution. pl,
<br />org,utic matter. Soils are gn
<br />are eight classes of coarse-f
<br />G\V, CP, CD1, GC. S\V, SP,
<br />fine-grained soils, identified
<br />and OH; :md one class of hid
<br />ns Pt. Soils on the bordcrlin
<br />designated b>' symbols for I
<br />CL-D4L.
<br />The AASII"FO s)'stem is u~
<br />ing to those Irt'operties th;
<br />cmtstructimt and nutintenanc
<br />classified in one of seven b
<br />A1- through .9-7 on the b.
<br />tion, liquid limit, and plant
<br />are gravelly soils which ht
<br />and are the best soils for s
<br />the other extreme, in group
<br />have low strength when u•e
<br />soils for suhgrade. \Vhcre la
<br />to ,justify a further breakrlo
<br />groups are divided as follmt
<br />A-2-5, A-2-G, A-2-7, A-7-!
<br />refinement, Lhe engineering
<br />be indicated by a group ind
<br />range from 0 for the best r
<br />the poorest (S). The AASII
<br />soils, with group index m
<br />shown in table 8; the estir
<br />soils mapped in the stn rey
<br />numbers, is given in table fi.
<br />mammals of natural
<br />mule deer, chukar,
<br />nd lark bunting.
<br />m•e classi fierl according to
<br />tsticih', liquid limit, and
<br />roped in 15 classes. There
<br />rained soils, identified as
<br />iDl, and SC; six classes of
<br />~s D'il., C1.,, OL, Al H, CH.
<br />Ohl)' organic soil, identified
<br />e behyeen two rlnsses arc
<br />loth classes; far example.
<br />~rl to classify soils accm-d-
<br />t affect use in higitwac
<br />~. In this s)'stem, a soil is
<br />sic groups ranging from
<br />xis of grain-size distribu
<br />city index In group A-1
<br />ae high hearing strength:
<br />bgrade or foundation. At
<br />A-7, :u'e clue soils, which
<br />and that are the poorest
<br />~nratm•c data arc availahlr
<br />t n, the A-1. A-?, and A-i
<br />and A-i-f,. As additional
<br />value of a soil material can
<br />~x number. Croup indexes
<br />iatertal Ln °0 or more for
<br />'0 classification for tested
<br />tubers in parentheses, is
<br />ated classification for all
<br />u~ea, tyithnut ~'1'oup index
<br />Soi[ properties significnnl in ,
<br />Several estimated soil pro
<br />neering are given in table G.
<br />for typical soil profiles, by I
<br />to have different significance
<br />estimates are based on field
<br />course of mapping, on test r
<br />soilsr and on experience vyiU
<br />other counties. Follotying tu'
<br />the columns in table fi.
<br />lliost soils in the Area arc
<br />that it generally does not
<br />andesite, and latite are at a r
<br />Celeste soils and at a depth
<br />bargo soils. Rhyolite nr IntitE
<br />inches in Tolman soils. Pre
<br />depth of 10 to 20 inches in Tr
<br />Depth to seasonal high tc
<br />from the surface of the soi
<br />ground water reaches in most
<br />Soil texture is dcscriberi i
<br />terms used by the Departm
<br />terms take into account ref;
<br />silt, and clay in soil materi;
<br />meters in diameter. "Loam,'
<br />vial that contains 7 to 2i pei
<br />silt, and less than fi°_ percen
<br />gravel or other particles co:
<br />priate modifier is added.
<br />loamy sand." "Sand," "silt,
<br />other terms used in USDA
<br />defined in the Clos.,;n y of thi
<br />Liquid limit and plasticit
<br />of water un the strength
<br />(S). As the moisture conic
<br />creased from a dry state, th
<br />semisolid to a plastic state.
<br />urther increased, the mate.
<br />n~incerinQ
<br />rerties significant iu engi-
<br />These estimates are made
<br />tyers sufficiently different
<br />for soil engineering. "fhe
<br />obscrvalions made lit the
<br />ata for Lhcsc :uul similar
<br />the same kinds of soil in
<br />explanations of some of
<br />ieep enough rarer bedrock
<br />(Feet their use. Rhcolite,
<br />epth of 10 to 20 inches in
<br />iC ?0 to f0 inches in Em-
<br />are at a depth of 10 to °0
<br />lominantly basalt is at a
<br />velers soils.
<br />tier table is the distance
<br />to the highest level that
<br />years.
<br />t table fi in the standard
<br />art of Agriculture. These
<br />five percentages of sand,
<br />i that is less than 2 milli-
<br />for example, is soil mate-
<br />eent clay, °8 to 50 percent
<br />sand. If the soil contains
<br />rser than s:uul, an appro-
<br />for example, "gravclh
<br />"clay." and some of Lhe
<br />texhu;il classification are
<br />survey.
<br />index indic;tte the effect
<br />and catsistaue of soil
<br />rt of a clayey soil is in-
<br />a material changes fl~nm a
<br />If the moisture content is
<br />ial changes from a plastic
<br />
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