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HomeMy WebLinkAboutOAK HILL APARTMENTS PUD - PRELIMINARY - 54-87L - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTPFPOPT OF A PprLit v-pt,Y SOILS ANI) MOCK INVESTMATION FnR KFry 1+011ES FORT CM.LINS, MUIRADO PROJECT Un. ?P.R7-79 PE: !!ARMNY FAR;'S StlMVISIrN PLAN "C" LARTMIrp MINITY, COLORAM nY ENPIPE LAPI- RATRPiF.S, INC. 2I4 !IC!?TN 11-mrs STREET FORT COLLINS, COLOPADO P052I 0 TABLE OF CONTENTS Tat -le of Contents..........•.•0000.eee0000..00eee.00es.eesss.o. i Letter of Transmittal . 000...o.00.o.000.....eo.......e...eoo.• r.�pore •oo...•000...000..eeee.•.ee....ss•.o..so..o.os�..�•...o.. 1 Anpen.lix A........ee...e....................................... A-1 �1cologic hap anti Test Rorinn Locatinn Plan .........e....e.... A-2 Yvy to Corings...... A-3 Log of Snrinns...eee.e....................................... A-4 Arpendix A..e..................................e.......e....e.. R-1 Sum-ery of Test Results ...................................... B-2 Appendix C.......e.........e................................... C-1 Soil Hap.....e...................................e........... C-2. Soils PescriptinnsC-3 Empire �bo torlesInc. Branch O Place f 1242 Bremwootl Placa Longmont, Colorado 80501 MATERIALS AND FOUNDATION ENGINEERS P.O. Box 1135 214 No. Howes Fort Collins. Colorado 80522 13031 776-3921 P.O. Box 429 (3031 484.0359 3151 Nation Way JLuuz`ty 1:, PESO Cheyenne, Wyoming 82001 P.O. Box 10076' (307) 632.9224 Kern Homes - PA Box 1845 font Co.ttna, Cotohado 8052t AttentLonf Xt. OexaM R. Ha.zton OeWement We cute pteaaed .to subalt oust Repo tt o6 a PaVal R V Sot" and Qtotogde UveaUga.tlon p+tepaaed bat the. Wpoaed it"Mentlat dtvetopme vt toeated aoudteae.t os Fost Colldna, Cotokado. The accompanyt Q Aepo)tt p+teaenta ou)c e.lndlitga .in .the subamlaee and oust ReeormnetuLt i..one based upon these ItndEngb. 110 ty/ tAuty 1/oune, W'Iff LABORATORIES THC. C'. PP NULL R. Shemod Seitton Eng•LneeAtV Geotog lax '1, �; ,y '�»........•• �o ;;_� Revtci%ae,f by: i1111�L '�•��c,�_ r♦ `S� sort, A Ched_teA C. .SvtM, F.E. :'``V�• e�°r0�6TE°q°Fame jyi�i Pxesijent - ° v s * 4.08 plah '• . ee OOa• O• ,• cc: J.N. Stauxu: ;•,t�•' Utt Kuq MEMBER OF CONSULTING ENGINEERS COUNCIL REPORT OF A PRELIMINARY SOILS AM GEOLOGIC INVESTIGATION SCOPE This report presents the results of a preliminary soils and geo- logic investigation prepared for the proposed residential development located south of Harmony Road, southeast of Fort Collins, Colorado. The investigation was carried out by re•ans of test borings and laboratory testing of samples obtained from those borings. The objectives of this investigation were to determine the geologic characteristics of the site and to determine the suitability of the site for construction purposes. SITF INVESTICATIGN The field investigation, carried out on December 20. 1979, con- sisted of drilling, logginq, and sampling fourteen (14) test borings. The locations of the test horings are shotim on the Geologic Map and Test Hnrinq Location Plan included in Appendix A of this report. Boring logs preparel from the field logs are included in Appendix A. These logs show soils encountered, location of sampling, and groundwater at the time of the investigation. A. surarary of the test results is included in Appendix P. All horings were advanced with a four -inch diameter, continuous- t.ype, power -flight auger drill. During the drilling operations, a soils engineer from Enpire Laboratories, Inc. was present and made a con- tinuous visual inspection of the soils encountered. A visual inspection of the site was made by an engineering geologist of Fmpire Laboratories, Inc. on 3anuary 11, 19RD. SITE LOCATION AM _DESCRIPTION The proposed site is located on the south side of Harmony Road, east of Fairway Estates, southeast of Fort Collins, Colorado. More particularly, the site is described as a tract of land situate in the northeast 'k of Section 1. Township 6 North, Range 69 West of the Sixth P.H., LArimer County. Colorado. The site consists of irrigated, cultivated farmland. An existing farm and outhuildinis are located alonq Harmony Road at the center of the site. A church exists at the northwest corner of the tract, and a large, shallow silage pit is located at the northeast corner of the property. The site is bordered on the west by Fairway Estates, a residential subdivision, and on the Past by Larimer County Road 13. The south property line is fenced. The 'tail Creek Ditch, a broad, shallow ditch approximately fivet (5) feet deep lined with large cottonwood trees, bisects the extremes southwest corner of the site. The slopes of the ditch hanks are approximately 1:1 and are vegetated with tall grass. The center of the property is vegetated with corn stubble, and the eastern and western thirds of the property consist of plowed ground. Large cottonwood trees line the east side of County Roar! 13 east of the property. and a few scattered trees are located along the south property line, along an irrigation ditch in the northeast corner of the. site, and adjacent to the existing farm c(mplex in the northern edge of the prop- erty. Several small irrigation laterals cross the site. In general, the property is relatively flat and gently sloping and has positive drainann to the southeast. In the extreme southwest corner on the southwest side of flail creek Ditch, drainage is to the southwest, SOIL AND GROUNWATE.R CMITION The soil profile at the site consists of strata of materials ar- ranged in different combinations. In order of increasing depths, they are as follows: 0 0 (1) Silty Topsoil: The site is overlain by a one (1) foot layer of silty topsoil. The upper six (6) inches of the topsoil has been penetrated by root growth and organic matter and should not be used as a fill and/or hackfill material. (2) Silty Clay: This stratum underlies the topsoil in all but Coring 5 and extends to depths two (2) to greater than four- teen and one-half (1411) feet below the surface. The silty clay is plastic and exhibits low to moderate bearing char. acteristics in its generally moist in situ condition. when wetted, the clay stratum exhibits slight swelling potential. (3) Sandy Silty flay The red granular sandy silty clay stratus: underlies the topsoil or upper clay layer in all but goring 9 and extends to depths twelve (12) to greater than fourteen and one-half (14h) feet below the surface. The lower clay stratum contains varying amounts of sand, is plastic, and exhibits low to moderate bearing characteristics in its moist to near - saturated natural state. I.'hen Netted, the clayier portions of the clay stratum exhibit slight swolling potentials. (a) Sandstone-Siltstone Bedrock: The bedrock was encountered in norings P. 99 11, 120 and 13 at depths four (4) to fourteen (14) feet below the surface and extends to greater depths. The bedrock consists nf interbedded sandstone and siltstone. The upper one (1) to two and one-half (?).1) feet of the bedrock Is highly weathered; however, the underlying interbedded siltstone and sandstone is firm and exhibits very high hearing characteristics. When wetted, the bedrock exhibits slight selling potential. (5) frounrlwaters At the time. of the investigation, free ground- water was encountered at depths three (3) to eleven and one- half (ilia) feet below the surface. Water levels in this area Are subject to change to due seasonal variations and irrigation demands on and adjacent to the site. General groundwater flow at the site is in a southeasterly direction following the topography of the site. In areas where proundwater does not lie above the bedrock stratum, surface water from pre- cipitation runoff and/or irrigation may bocor.+e trapped on the relatively impervious bedrock stratus+, creating a perched water condition. RE nitHEMATIONS AND DISCUSSIMI It is our understanding that the proposed site is to be developed for single-fanil.y residential construction. Due to the tnpography of the property, ninon site grading is anticipated. r-pology The proposed site is located within the Colorado Piedmont section of the meat Plains physiographic province. The Colorado Piedmont, forrapii (Wring Late Tertiary and Early Quaternary time (approximately 65 million Years ago), is a hroad, erosional trench which separates the Southern rocky Mountains from the Nigh Plains. Structurally. the area lies along the western flank of the Denver !Basin. nuring the Late liesozoic and Early Cenozoic Periods (approximately 70 million years ann), intense tectonic activity occurred, causing the uplifting of the Front Pange and the associated downwarping of the nenver Basin to the east. Relatively flat uplands and broad valleys characterize the present-day topography of the Colorado Piedmont in this region. The area is underlain by interbedded sandstones and siltstones of the Cretaceous Pierre Formation. The Pierre shale is overlain by residual and alluvial clay soils of Pleistocene and Recent Age. 0 Pedrock outcrops were not encountered at the site; however, bedrock was encountered in several test borings at depths four (4) to fourteen (14) feet below the surface. It is estimated that the bedrock underlies the remainde3r of the site at depths fifteen (15) to twenty-five (25) feet below the surface. The regional dip of the bedrock in this area is slight and in an easterly direction. Fron a structural standpoint, the property should be relatively free of seismic activity. Due to the relativelyy gentle slope of the sit% geologic hazards due to mass movement caused by gravity, such as landslides, mud slides, etc., are not anticipated an the property. With proper site grading around all structures and adequate drainage for roaMys, erosional problems should be minimal. It is recow*nded that all areas stripped of vegetation in open areas he reseeded to help mininize erosion. Adequate culverts should he provided below all roadviays where they cross any minor drain- ages or swales. The property lips within the drainage basin of the Cache La Poudre River. ilijnr drainage At the site is through a natural drainage gray at the southwest corner of the property. The extreme southwest corner of the ;property on the south side of Mail Creek Ditch drains in a southwesterly direction into Mail Creek, which is a tri- butary of Fossil Creek. Fossil Creek drains into the Cache La Poudre River drainage well east of the site. The property does not lie within the flood plain of the Cache La Poudre River or that of bail Creek and should not he subject to flooding by either of these streams. The geologic conditions at the site necessary for the formation of cnal, lirestone, quarry rock. and sand and gravel are not present, in our opinion, to economic depths. Therefore:, the property should not be considered as economic source for any of these minerals. Site .(1raelinq And Utilities Anticipated grading of the site indicates that foundations and/or slabs on grade in.portions of the site ray be founded on structural fill. Since there May he building foundations resting on filled ground and/or the dnpth of fill W ou floor slabs in portions of the site may exceed that permitted by the flinimum Property. Stan� Standards. fill placement should he carried out in accordance with FHA "pata Sheet 79G.• Specifi- cations pertaining to site grading are included below. It is recnnw.nded that the upper six (E) inches of all topsoil below filled and paved areas be stripped and stockpiled for reuse in planted areas. All trees, brush, shrubs and other debris should also he removed. The upper six (6) inches of all suhgrade below filled areas should he scarified and recompacted two percent (2f) wet of optima roisture to at least ninety percent (M) of Standard Proctor Density AST11 n M, 7n. All fill should consist of the on -site soils or imported material approved by the soils engineer. It should he noted that bedrock used as fill should be broken into pieces less than six (6) inches. in diameter. Excavation of the bedrock may be accomplished by heavy-duty construction equipment ernuivalent to a n-9 tractor. Proper- placement of the bedrock as fill ray ha difficult and could reqoiire the use of a disc or other mixinq equipment to ohtain. uniform mmisture and proper com- paction. There possible, the bedrock should he used as fill in open and planted areas or in the lower portion of fill below paved and building areas. The fill should be placed in uniform six (6) to eight (n) inch lifts. Each successive lift of fill placed on hillsides should he benched slightly into the existing slope. Recause of the expansive nature of the subsoils, all fill should be compacted two percent (2%) wet of optinum misture to at least ninety-five percent (95x) of Standard Proctor Pensi ty ASTM p GO N 7P. For stability. all cut and fill slopes should he designed on grades no steeper than 3:1* nil utility trenches dug in the upper clay soils four (4) feet or nrnre in depth should be excavated on slopes no steeper than lsl. The firdrock nay be excavated on vertical slopes. Excavation of the bedrock may require the use of heavy-duty construction equipment. Where u- tilities are excavated below grnundwater, dewatering will be required during placement of pipe and hackfilling to insure proper construction. All piping should be bedded to insure proper load distribution and to eliminate breakage during the hackfillinq operations. All backfill placed in utility trenches in open and planted areas should be compacted in uniform lifts at optimum misture to at least ninety percent (90%) of Standard Proctor Density ASTM D 69FI-70 the full depth of the trench. The upper four (4) feet of backfill placed in utility trenches under roadways and paved areas should bO compacted at or near optimun moisture to at least ninety-five percent (95%) of Stand- ard Proctor Density ASTMM D 69 8-7ne and the lower portion of these trenches should he compacted to at least ninety percent (90%) of Standard Proctor Density ASTM D (OP- 7p. Addition of misture and/or drying of the sub- soils nay be required to assure proper compaction. Proper placement of the bedrock as backfill may be difficult, as is discussed above. All stripping, grubbing, subgrade preparation, and fill and backi. fill placer.►ent should he done under continuous observation of the soils ennineer. Field density tests should he taken daily in the compacted subs rade, fill, and backfill under the direction of the soils engineer. Foundation In view of the loads transmitted by proposed residential construc- tion and the soil conditions encountered at the site, it is recommended that the structures be supported by conventional -type spread footings and/or grade hears. All footings and/or grade beams should be founded on the n riginal, undisturbed soil or on a structural fill extended to the undisturbed soil A minintin of thirty (30) Inches below finished grade, for frost protection. The structural fill should be constructed in accordance with the rpcormw—ndations discussed in the 'Site Grading and 11tilities° section of this report. Since it is anticipated that structural fill material will cmer frru� cut sections at the site, the properly placed structural fill should have similar physical properties and hearing characteristics to those of the undisturberd, natural sub- soils at the site. The structural integrity of the fill as well as the identification and undisturbed nature of the soil should he verified by Ole soils engineer prior to placement of any foundation cnncrete. Rased on preliminary test results, footings and/or grade beams founded at the shove levels gray he designed for a maximum allowable bearing capacity of one thousand to two thousand (200n) pounds per square foot (dead load plus maximum live load). To counteract smelling pressures which will develop if the subsoils become wetted, all footings and/or grade bears should he designed for a minimum dead load of two hundred fifty (2,P) t.n five hundred (5nn) pounds per square foot. Pa_serents and/or Slabs on Crade Aasetrent construction is feasible over the majority of the site provided all finished haserent floor slabs are placed a minimum of three (3) feet above existing groundwater elevations and/or a minimum of three (3) feet above the bedrnck stratum. In view of the relatively shallow depth to grnunr%�ater recoreed along the eastern portion of the site, it is our opinion that has"ent construction is presently not feasible in this area. (See Geologic Van and Test Poring Location Plan.) Basement construction re y become feasible in this area if the grading plan for the site is such that h.uilding graces are raised or if the area is drained or if perimeter drains are placed around each individual base- ment area. It should he noted that any drainage system constructed at the site should he designed with an adenttate Outlet, St►tgrade below slabs on grade shnuld he prepared in accordance O th the rorrrr,endations discussed in the "Site Grading and Utilities' section of this report. All slabs on grade should he underlain by a minimum of four (4) inches of gravel Or crushed rock devoid of fines. Streets Soils were classified and group indexes determined by AASHO Method M M-4g at various locations within the proposed development for the purpose of developing preliminary criteria for.pavement design. Group indexes of the upper soils at the site based on the AASHO P145-49 designatinns vary from S.A to IM,. Itsing an average group index of 9 as the criterion for pavement design, recommended preliminary pavement thicknesses for the site are as follows: ® 0 Residential Streets Select Gravel Base Course 5° Asphaltic Concrete ?" Total Pavement Thickness 7" Collector Streets Select Gravel Pase Course 8" Asphaltic Concrete z" Total Paverent Thickness 10" Arterial Streets Select Subbase 5" Select Gravel (base Course 6" Asphaltic Concrete ?" Total Pavement Thickness 13" All topsoil, organic natter, and other unsuitable materials should he stripped and removed from the street subarade prior to placing any fill rrterial, subbase, or base course. The finished subgrado should he a minirum of three (3) feet above existing groundwater elevations. All subbase, base course, and asphaltic concrete shall meet Larimer County and/or Colorado nopartment.of Highways specifications and should be placed in accordance with these specifications. GEti .PAI C^tfitENTS It should be noted that this was a preliminary investigAtion and that the hearing capacities recommended in this report are based on preliminary tests. [)ue to variations in soil conditions, swelling pressures, and groundwater conditions encountered at the site. it is recommended that additional test horings be made prior to construction. Samples obtained from these test borings should he subjected to testing and inspection in the lahoratnry to provide a sound basis for deter- winins the physical properties anal hearing capacities of the soils encountered. No Text �r I : TEST BORING LOCATION PLAN E n L-X �P1LJ3RE-;0F?r-1-6-T-1QtJ _C-.. - 77M1 0 KEY TO BORING LOGS I- i TOPSOIL �•��� GRAVEL ® FILL SAND &GRAVEL i SILT SILTY SAND & GRAVEL '-r7—.-I CLAYEY SILT o oa COBBLES DSANDY SILT ` o: SAND, GRAVEL & COBBLES ® CLAY WEATHERED BEDROCK i SILTY CLAY SILTSTONE BEDROCK SANDY CLAY ® CLAYSTONE BEDROCK a SAND tazi SANDSTONE BEDROCK �'•�� SILTY SAND LIMESTONE CLAYEY SAND , x ,max GRANITE SANDY SILTY CLAY SHELBY TUBE SAMPLE STANDARD PENETRATION DRIVE SAMPLER SZ WATER TABLE 6 DAYS AFTER DRILLING C T- HOLE CAVED 5112 Indicates that 5 blows of a 140 pound hammer falling 30 inches was required to penetrate 12 inches. A- 3 0 0 LOG OF BORINGS 5005 5000 4995 4990 4985 49 RO 4975 4970 Fjo• 2 � [�:i 1 1 e e 1 FiiTSei I u topographic map . 1 by li -.-Co.n.sul-ting Fngineersdated April. i :•• :I EMPIRE LABORATORIES, INC. 5000 4995 4990 4985 4980 4975 4970 4965 LOG OF BORINGS 5L hlo.5 IVo. 6 _Ua-Z 1�tc• B A- 5 EMPIRE LABORATORIES, INC. LOG OF BORINGS 4990 4985 4980 4975 4970 4965 4960 4955 A- 6 EMPIRE LABORATORIES, INC. LOG OF BORINGS 4980 4975 4970 4965 4960 AL. Alo . l3 No .14 A- 7 EMPIRE LABORATORIES, INC. No Text SUMMARY OF TEST RESULTS BORING DEPTH DRY DENSITY UNCONFINED COMPRESSIVE WATER SOLUBLE STRENGTH—P:S.F. SULFATES—°o PENETRATION BLOWS/INCHES NO. . MOISTURE P.C.F. 1 3.06-4.0 19.9 97.2 2100 9./12 4.0-5.0 10/12 7.0-8.0 16.7 7/12 13.5-14.5 24.1 10/12 2 3.0-4.0 20:.7 7.0- 8. 0 13.6 1 i09. 4 3160 9/12 8.0-9.0 17.1 6/12 13.5-14.5 22.8 3 3.0-4.0, 21.3 92.1 1650 8/12 4.0-:5.0 18.9 5/12 7.0- 8.0 21.5 6/12 � 13.5-14.5 26..8 4 3..0-4.0 25.3 103.5 2640 1:1/12 4.0-5.0 17.9 6/12 8.0-9.0 25.2 50/12 13.5-14.5 9.8 I EMPIRE LABORATORIES, INC. SUMMARY OF TEST :RESULTS BORING NO. DEPTH FT. % MOISTURE DRY DENSITY P.C.F. UNCONFINED COMPRESSIVE STRENGTH-P.S.F. WATER SOLUBLE SULFATES--% PENETRATION BLOWS/INCHES 7/12 5 3.0-4.0 8.6 7.0-8.0 3.6 1/1.2 8.0-9.0 9.6 28/12 13.5-14.5 11.5 6 3.0-4.0 21.2 103.3 5900 8/12 4.0-5.0 16.6 12/12 7.0-8.0 19.3 10/12 13.5-14.5 16.4 8/12 7 3.0-4..0 22.3 7.0-8.0 21.0 100.3 600 4/12 8.0-9.0 23/12 13.5-14.5 12.6 8 3.0-4.0 17.3 100.7 3490 9/12 4.0-5.0 18.6 8/12 7.0-8.0 19.1 34/12 13.5-14.5 119.0 EMPIRE LABORATORIES, INC. BORING NO. DEPTH FT MOISTURE 9 3.0-4.0 24.0 7.0-8.0 18.6 8.0-9-.0 18..8 13.5-14.3 18.1 10 3.0-4.0 21.5 4.0-5.0 .23.6 7.0-81.0 22.2 13.5-14.5 13.2 11 3.0-4.0 27.8 4.0-5.0 24.9 8.0-9.0 18.9 13.5-14.5 17.8 12 3.0-4.0 22.9 4.0-5.0 23.8 7.04.0 13.8 13.5-14.2 16..4 SUMMARY OF TEST RESULTS DRY DENSITY UNCONFINED STRENGTH-P.S.F. COMPRESSIVE SSIVE P.C.F. 102.6 1880 102.1 1' 2800 91.3 1 640 97.0 1 1190 WATER SOLUBLE SULFATE S-90 PENETRATION BLOWS/INCHES 5/12 44/12 50/9 6/12 5/12 24/12 3/12 13/12 36/12 5/12 17/12 50/8 71 EMPIRE LABORATORIES, INC. BORING NO. 1.3 14 DEPTH FT. 3.0-4.0 4.0-5.0 7.0-8.0 13.5-14.5 3..0-4.0 7.0-8.0 8.0-9.0 13.5-14.5 MOISTURE 26.3 26.0 18.5 20.1 22.7 22.9 17.9 18.6 SUMMARY OF TESTRESULTS DRY DENSITY UNCONFINEDSTRENGTH-P.S.F. COMPRESSIVE P:C.F. 96.7 1690 9P.6 1770 WATER SOLUBLE SULFATES- io .i PENETRATION BLOWS/ INCHES 4/12 6/12 18/12: 5/12 7/12 10/12 L' EMPIRE LABORATORIES, INC. I 0 0 SUMMARY OF TEST RESULTS Swelling Pressures Boring Depth % Moisture Dry Density Swelling No. (Ft.) Before Test P.C.F. Pressure PSF 1 3.0=4.0 19.9 88.7 55 2 7.0-8.0 13.6 113.0 370 6 3.0-4.0 21.2 104.1 240 8 3.0-4.0 17.3 111.6 465 9 7.0-8.0 18.6 106.0 170 Atterherg Summary Boring Number 1 4 8 13 Depth (Ft.) 3.0-4.0 3.0-4.0 3.0-4.0 3.0-4.0 Liquid Limit 29.8 35.1 35.3 31.5 Plastic Limit 21.6 18.8 18.1 17.8 Plasticity Index 8.2 16.3 17.2 13.7 % Passing No. 200 Sieve 63.6 80.6 66.0 86.3 Group Index: AASHO M145-49 5.8 10.5 9.1 9.5 AASHTO M145-73 3.4 12.1 9.1 10.7 Classification LIn i f i ed CL CL CL CL. AASHTO A-4(3) A4(12) A-6(9) A-6(11) n r, No Text ■r ST4TC- F-WY 68L _a Tom.- C-2 RAPIRF I ARnRATnRIF% INS'. _ ......_ .. - Combined II ABC RLM 61 70 l 1111 ftAi t- p J J KS Un&wer ('8levins) gravelly loam (31K2, 031)(1) LRA 66 1',oderately deep to deep soils with good to excellent moisture holding capacity. Air, water, and root penetration is good. Top soils are loams or gravelly loams, and subsoils are gravelly clays. They generally have underlying limey sands, gravel, or cobbles at depths of 30 to 50 inches. Small areas of these calcareous gravels are lime cemented and concrete -like. Land Capability Units Soil Group 8, 12 Slope Irrigated Group 0-3% IIIe3 Class III Irrigated Land. Care needed to prevent B water erosion. Leveling may be limited by under- lying gravels. Slopes less than 3 feet in 100 feet. 3-9% IVel Class We Irriga-ted Land. Extreme care needed C,D to prevent water erosion. Leveling and crop yields may be limited by depth of gravels. Best suited to permanent vegetation. Slopes range from 3 to 9 feet in 100 feet. Non -Irrigated 0-3% IIIs61 Class IIIs Non -Irrigated Land. Clayey soils and a depth to gravel limits capability. Slopes are less than 3 feet in 100 feet. 3-9% VIe Class Vle Non -Irrigated Land. Severe water erosion C,D hazard and depth to gravels limits.capability. Best suited to permanent vegetation. Slopes range from 3 to 9 feet in 100 feet. Loamy Plains Range Site n+ Combined II ABC ® P2/68 OAP 3/5/68 CPP T2 Nunn clay loam (2221, 22J1) Resource Area 68 Deep clay loams with excellent moisture holding capacity. there may be underlying sands or gravels at depths of 40 to 60 inches. Air and root penetration is slow. The surface soils are sticky when wet and crust and crack when dry. Land Capability Units Soil Group 7 Slope Irrigated Group 0-1% IIsl Class Its Irrigated Land.. Careful irrigation is A necessary to get good water penetration. Slopes are less than 1 foot in 100 feet. 1-3% ITel Class IIe Irrigated Land. Very careful irrigation is B required to get good water penetration and prevent erosion. Slopes range from 1 to 3 feet in 10.0 feet. 3-5% IIIe2 Class .IIIe .Irrigated Land. Special care needed to C control water erosion. Slopes range from 3 to 5 feet in 100 feet. Non -Irrigated 0-3% IIIs61 Class IIls Non -Irrigated Land. Capability is limited A,B by soil textures. Slopes are less than 3 feet in 100 feet. 3-5% IVe70 Class IVe Non -Irrigated Land,. Water erosion hazard C Limits capability. Slopes range from 3 to 5 feet in 100 feet. Loamy.Plains Range Site. r_n Combined II ABC T21 Nunn clay loam, seeped (2221. 22J1) 1/15/68. CPF 1/18/68 OAP Resource Area 68 Deep clay loams with excellent moisture holding capacity. There may be underlying sand or gravels at depths of 40 to 60 inches. Water tables occur at depths of 30 to 54 inches. Air and root penetration is slow. The soils are sticky when wet, crust and crack when dry, and are hard to work. Soil Group 7 Land Capability Unit Slope Irrigated Group 0-3% Ilewl• Class Ilew Irrigated Land. Care in irrigation is needed AOB because of high water tables, saltaccumulation and clay loam textures. Drainage and salt reduction needed for maximum production. Slopes range from 0 to 3 feet in 100 feet. Non -irrigated 1-3% VW Class Vw Non-IrrigatedLand. High-water table limits $ capability. Water tables may be beneficial. Slopes range from 0 to 3 feet in 100 feet. Wet Meadow Range Site.