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<br />52
<br />
<br />(;:)
<br />
<br />consisting of clay loam in th~ top horizo~ with sandy '?am in ~~e
<br />~ubsoil and substratz\. VariuUons from tIns u~lIltl type me.hlde silt
<br />loarns and ~!l.ndy lonms in tbe topsoil n.nd clay loams and silt )oum~
<br />in the. subsoils u.nd s\lb~tn\lJa. The class t lands genera.lt.y '::ilope shghtly
<br />less tho.n 1 percent and are smo,oth to ~lightly t1.ndulatlng.
<br />No drainage problems nre enclent nnd the sUlls are free of hA.rmful
<br />accumulnt,ions of soluble ~nlts and alkali.
<br />
<br />Class Ie
<br />Limitllt.iolls of potential productivity under IH".erllge management
<br />or somewhat higher cJe\~e]opmellt ,costs re.sul.ted In 67,395 Rcres, or
<br />40 percent. of t.he irrigable n.rea, bemg pla.ced In ~lB.s~ 2: Cluss 2 lands
<br />have a. composite producthity potential tlIal IS .sJ.gni.fl.cnnt~y low~r
<br />tha1\ that. of the class 1 la.nds. To achie.ve mB.'{UlH\ffi effi('.lency m
<br />water utilization or to pro vidA adequate farm drainage, develop~ent
<br />work with costs ranging rrom norninw sums to :ti70 per acre will he
<br />
<br />req uired.
<br />Of the total closs 2 lands, 39,840 acres are smooth and nearly level.
<br />These lands are free of t.opographic limittl.tions, but because of CQarse-
<br />textured, moderately sbaUov..', or saline soils) production o~ ~6 percent
<br />of these lands will be only moderal.ely high, For the remaIn1l1g 4 per-
<br />cent of the class 2 lands with nearly idenl topography, the subsurf8;ce
<br />drainage is inadequate, and drainage works, es.timated to requITe
<br />moderate costs, 8l'e recommended. In case the dramage ''r"orks are .not
<br />installed, production on these lands will als~ be, only moderately hlgb,
<br />Closs 2 lands with correctable topographIC lirllltatlOns total 24,735
<br />acres. These lands slope less t.han 3 percent but are undulating, The
<br />soils are deep and medium textll..r~d. except for minor !"reas. of sandy
<br />loa.m. Gra.ding these la.nds tAl elim,?8.te the lln~~ue.tlons IS ~ecom-
<br />mended, This development work, whIch would facilitate spre~dIng the
<br />water could be accomplished at moderate costs. Productlon from
<br />these'lands, although IlIgh, will be slightly below that of the closs 1
<br />
<br />lands, 'limi" h
<br />Class 2 lands t.otali.n.e 2,820 acres have topographIC t.atlOns t at.
<br />are not correc.tahle. These lands lie on slopes ranging from 3 to 6
<br />percent. Their soils are mainly medium textur~d and moderat:ely de.ep.
<br />In irrigating these lands, care SllOUJd be exercised ~o keel? so~ erosIOn
<br />at a minimum. Development work to be ac~ornplisbe~ ~s minor and
<br />can be accomplished aL low cost. ProductIOn 16 anticipated t,o be
<br />
<br />moderately high,
<br />
<br />Class 3
<br />Lands totaling 34,820 acres, or 21 pere~n~ of the irr!gnhle area,
<br />were assigned to cluss 3. These lands hfl.ve liIDltatlOns sLDuler t.o t.hose
<br />of the class 2 lands, but the severity oC the Limitations is greater.
<br />Of the class ~ lands 15905 acres are smooth and nearly level.
<br />About 84 percent of th~Be l~nds have deep soils tnll.t are medium and
<br />fine textured, They are potentially eapable of moderRtely bigh pro-
<br />duction but in order to reac.b their rull potentIal, farm dro.lTIage
<br />works ~ be required to stabilize the water table at lower lC\Tcls.
<br />Tbe costs for this develupment were est.imated to range from $70 t.o
<br />$130 per acre, ' , "
<br />Production from the remammg 16 percent of the smooth and nearly
<br />level class 3 lands is expected to be qUite lo\\.' because of coarse-textured
<br />or shallow soils. Soil textures range from loamy sands to clay loams,
<br />
<br />! '..
<br />t ..
<br />
<br />',"
<br />
<br />.-
<br />
<br />53
<br />
<br />buL in instances where the te.."<ture is favorable the soil is shallow,
<br />being underlain by eoarse sand or gravel at depths of 18 to 24 inches,
<br />In some instances the soils are underlain by shale at depths of about
<br />36 inches. Required development work can be accomplished at low
<br />costs tuld slopes are sufficient to provide a.dequate drainage.
<br />Class 3 lands with correctable topographic limitations total 2,750
<br />acres, These lands slope less, than 3 percent but have pronouneed
<br />undulations, To accomplish efficient irrigation, the undulat.ions must
<br />be eliminated, Estimated development eoslS range from $70 to $130
<br />per acre, On about one-third of th""e lands, however, part of the esti-
<br />mated development eoslS were for improving tbe drainage, Soil depths
<br />are sufficient to permit the required grading, but due to coarse
<br />textures in many instances and fine text.ures to n lesser extent produc-
<br />tivity will be only moderatley high. In some Mess, however, productiv-
<br />ity will approach tbat of closs 1 lands after farm drainage improvements
<br />are completed,
<br />Closs 3 lands totaling 6,415 acres are gradient lands with slopes
<br />ranging from 3 to ]0 percent, These lands have two types of topo-
<br />gro.ph.ic limitfLtions-gradien t and undulating surfnces. The undulating
<br />factor is correctable, but the gro.dient condition is not. Estimated
<br />costs for grading to remove the undulations range from $70 to $130
<br />per nerO. The soils of tbese lands n.re medium textured a.nd deep.
<br />After full development, production is expected to be moderately high,
<br />Otber closs 3 lands totaling 5,920 aeres have non correctable topo-
<br />graphic limitations associated with soil limitations. These lands have
<br />slopes ,vithin tbe 3 to 6 percent range, and the soils are generally
<br />coarse textured. In some instances, however, lands with fine-textured
<br />soils are represented in this group. Development costs were estimated
<br />to be low, but crop yields are expected. to be moderately low.
<br />The remaining 3,830 acres of doss 3 gradient lands have long, even
<br />slopes within the 6 to 10 percent range. These lands have medium-
<br />textur~~d soils wbich are moderately deep_ Production Crom these
<br />lands IS expected to be moderately low and because of the soil erosion
<br />hazf\rd they are much better adapted to close-growing crops than to
<br />row crops. Required deveJopment costs were estimated to be low.
<br />
<br />Class GW irrigaud-Nonirrigab/e
<br />
<br />~here are 27,185 acres of class 6W lands in the project service area.
<br />Nelt.her these nor the class 6 lands meet the minimum requirements
<br />speeJlied by Bureau of Reelamation standards for irrigable lands,
<br />However, the class 6W lands have water rights, are presently irrigated,
<br />and will continue to receive their historic water supplies but. ",.-ru not
<br />receive project supplemental water,
<br />Sizable iracts of class 6W land occur at elose intervals from the
<br />upper to the lower part of the project area, with most of it being located
<br />on the terraces and comprised or lands having soils of ver:r coarse
<br />,e'ture or compact clays, On the uplands the soils of the 6W land.
<br />a~e ur:derlain by sh8:1e or sandstone at very shallow depths. Lands
<br />\\"ILh rnadequAte dramage and high wnt.er tables cuusing saline or
<br />snline-ulknlille conditions are generally located on the low terraces.
<br />
<br />TOPOGRAPH Y
<br />The irrigable and irrigated lands of the Narro\\'s unit occupy a
<br />portion of the,Colorado Piedmont Plain, The general slope of the plain
<br />
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