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<br /> <br />E7alIBIT D-2 <br />Page 2 <br />;i9e '~~eT161'cli Soil M~~ was prapa~ed by delineating eight meppinq units that <br />iiifar irv.e each o'char l.r. the kinds of soil that nre present. The Boils <br />~~.~ 2:~C.9 .~:2plnq unit are asaacieted end form patterns that nre repeated from <br />.JL S.',d iCO.yf+a~e. They were2 ;:a Pined and described eccordinq to requirements <br />~trpc~ed ay t~.a map-oaale an.i criteria f;an ,the Comprehensive System a! <br />Soi's C_a>6bcicet:on, adop~Ed.:n January 1965. The composition of the units <br />d:ony witi7: re:aCed rharzaLeristics end.intztpretative information ere shown <br />in Table i:. RaaderE interested in more detailed information about the <br />classification: s~stw.~ ehoula consult technical publications. ~. <br />., <br />~.:.reuga ;~istribu~ion of a,appinq unite end percent that each occupies is <br />5:vcn in :'uU1e 2. Coaposi9:ion and related characteristics of each soil <br />sapping unli &:a gluon in eha following brief narrative descriptions. <br />Soil Mappkng Unit lr Light=colored soils of the deserts <br />This unit is in 7lsappointment Valley, mostly in San Hiquel County, uut a <br />small part extends into Dolores County. This unit is one of the least <br />extensive ir.'tY~e basin. Water intake is slow and runoff is rapid. Erosion <br />is iaoderace to severe and sediment yield ie in ~:he sange of 1.0-3.0 acre- <br />feet per square mile per year. <br />Tne landscape is characterized by a wide oblong valley with rolling shale <br />hi1Ta on the north and east and steep barren shale hills to the south- <br />2ast., There are :navy int2cmictent drainagewaya into Disappointment Creek. <br />Most of theca S:-ainagewaya afe eroded to depths of 10 to 20 feet and widths <br />of IO to 50 feet. A sparse cover of shadacale is present with some sagebrush. <br />rebnitbrush, and greasewood along the drainageways. On the upper reechee <br />of ~che valley them are a few pinyon-juniper. <br />Tnere are tnree~najo: 5~oups of soils in this unit. Shallow soils derived <br />iro,r. Mancos Sr.aie ~;.cwc up about 50 percent of the unit. They have light- <br />coloced, ca~;;areoLa, surface layerer are low in organic matter and have fine <br />and moderately i,.na caxtc:rea.. These soils are on rolling hills, mainly <br />o:: rite nor"t;i an6 east ride of Disappointment Creek. Another 35 percent of <br />the +.rnit cor.~ists of naep and moderately deep fine textured ellvvial soils. <br />These soils are ~iony Disappointment Creek. They usually have light-colored <br />surface iayera aithouyh in the upper reaches of the valley they become <br />aarker. The soils are rauaetately saline-alkali and have a aloes permeability <br />rata.. Ti.~~ remaining 15 percenr of the unit consists of reddish-broom, <br />moderately deep soils on small terraces, mainly on the south and went side <br />of Disappointment Creek. Surface layers are light-colored and the <br />permeability rate is moderate. <br />So1I SurvAy Staff, SCS, USDA <br />"Soil Classification, a Comprehensive System 7th Approximation." <br />1966 had as amended through October 1966. <br />2/ Aanaahl, Andrew R. <br />"The First Comprehensive Soil Classification System" Journal of <br />Soil end Water Conservation 20:243-246, 1965.' <br />