In cooperation with theUSDI—Bureau of LandManagement, County ofMoffat, Colorado First SoilConservation District, andthe Colorado AgriculturalExperiment Station

Soil Survey ofMoffat CountyArea, Colorado

United StatesDepartment ofAgriculture

NaturalResourcesConservationService

Detailed Soil Maps

The detailed soil maps can be useful in planning the use and management of small areas.

To find information about your area of interest, locate that area on the Index to Map Sheets. Note the number ofthe map sheet and turn to that sheet.

Locate your area of interest on the map sheet. Note the map unit symbols that are inthat area. Turn to the Contents, which lists the map units by symbol and name andshows the page where each map unit is described.

The Contents shows which table has data on a specific land usefor each detailed soil map unit. Alsosee the Contents for sections of thispublication that may address yourspecific needs.

3

How To Use This Soil Survey

4

This soil survey is a publication of the National Cooperative Soil Survey, a jointeffort of the United States Department of Agriculture and other Federal agencies,State agencies including the Agricultural Experiment Stations, and local agencies.The Natural Resources Conservation Service (formerly the Soil ConservationService) has leadership for the Federal part of the National Cooperative Soil Survey.

Major fieldwork for this soil survey was completed in 1989. Soil names anddescriptions were approved in 1990. After 1990 join units from the adjacent DinosaurNational Monument and Uintah Area, Utah soil surveys were added to the Moffat soilsurvey area. Unless otherwise indicated, statements in this publication refer toconditions in the survey area in 1989. This survey was made cooperatively by theNatural Resources Conservation Service and the United States Department ofInterior Bureau of Land Management, County of Moffat, Colorado First SoilConservation District, and the Colorado Agricultural Experiment Station. The survey ispart of the technical assistance furnished to the Bureau of Land Management and theColorado First Soil Conservation District.

Soil maps in this survey may be copied without permission. Enlargement of thesemaps, however, could cause misunderstanding of the detail of mapping. If enlarged,maps do not show the small areas of contrasting soils that could have been shown ata larger scale.

The United States Department of Agriculture (USDA) prohibits discrimination in allof its programs on the basis of race, color, national origin, gender, religion, age,disability, political beliefs, sexual orientation, and marital or family status. (Not allprohibited bases apply to all programs.) Persons with disabilities who requirealternative means for communication of program information (Braille, large print,audiotape, etc.) should contact the USDA’s TARGET Center at 202-720-2600 (voiceor TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights,Room 326W, Whitten Building, 14th and Independence Avenue SW, Washington, DC20250-9410, or call 202-720-5964 (voice or TDD). USDA is an equal opportunityprovider and employer.

Cover: Breaks into the Little Snake River just north of its confluence with the Yampa River.The dominant soil map units shown include Torriorthents-Rock outcrop, shale complex, 30 to 75percent slopes and Vermillion-Langspring complex, 3 to 25 percent slopes.

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Contents

How To Use This Soil Survey ................................. 3Foreword ............................................................... 15

General Nature of the Survey Area ................... 17History ........................................................... 17Water Supply ................................................. 18Industry and Transportation ........................... 19Recreation ..................................................... 19Natural Resources ......................................... 19Agriculture ..................................................... 19Physiography ................................................. 20Geology ......................................................... 20Climate .......................................................... 23

How This Survey Was Made .............................. 24Detailed Soil Map Units ....................................... 27

1—Abor silty clay loam, 12 to 25 percentslopes .......................................................... 28

2—Abor silty clay loam, 25 to 65 percentslopes .......................................................... 28

3—Adderton loam, 1 to 10 percent slopes ........ 294—Almy loam, 3 to 15 percent slopes ............... 295—Apmay clay loam, 0 to 1 percent slopes ...... 306—Avalon-Mack complex, 1 to 12 percent

slopes .......................................................... 307—Avalon-Persayo, moist-Degater complex,

3 to 30 percent slopes ................................. 318—Badland ........................................................ 329—Baroid-Eghelm complex, 0 to 3 percent

slopes .......................................................... 3310—Battlement fine sandy loam, 0 to 3

percent slopes ............................................. 3411—Battlement silt loam, saline, 0 to 3

percent slopes ............................................. 3412—Berlake sandy loam, 3 to 12 percent

slopes .......................................................... 3513—Berlake sandy loam, 12 to 25 percent

slopes .......................................................... 3514—Berlake-Maysprings complex, 3 to 12

percent slopes ............................................. 3615—Berlake-Taffom-Gretdivid complex,

10 to 20 percent slopes ............................... 3716—Bilhil clay loam, 0 to 3 percent slopes ........ 3817—Binco gravelly clay loam, 15 to 45

percent slopes, very stony ........................... 3918—Boltus-Beamton complex, 2 to 12

percent slopes ............................................. 39

19—Borollic Natrargids-Borollic Haplargids-Ustic Torrifluvents complex, 0 to 20percent slopes ............................................. 40

20—Brownsto-Castee complex, 3 to 25percent slopes ............................................. 41

21—Bulkley stony loam, 15 to 30 percentslopes, very stony ........................................ 42

22—Bulkley silty clay, 3 to 12 percent slopes .... 4323—Bulkley silty clay, 12 to 25 percent

slopes .......................................................... 4324—Bulkley-Quilt complex, 12 to 45 percent

slopes .......................................................... 4425—Campspass fine sandy loam, 3 to 12

percent slopes ............................................. 4526—Campspass fine sandy loam, 12 to 25

percent slopes ............................................. 4527—Canlodore very cobbly loamy sand,

15 to 40 percent slopes ............................... 4628—Carbol-Irigul-Rock outcrop complex,

3 to 25 percent slopes, very stony ............... 4629—Carbol-Miracle complex, 3 to 12 percent

slopes .......................................................... 4730—Carmody-Rock River-Crestman

complex, 6 to 15 percent slopes .................. 4831—Castee loam, 3 to 12 percent slopes ......... 4932—Chroder sandy loam, 3 to 12 percent

slopes .......................................................... 4933—Clayburn loam, warm, 3 to 25 percent

slopes .......................................................... 5034—Clayburn-Foidel complex, 25 to 55

percent slopes, very bouldery ..................... 5035—Clayburn-Youga, moist complex,

15 to 45 percent slopes ............................... 5136—Clifsand-Chroder complex, 3 to 12

percent slopes ............................................. 5237—Cochetopa loam, 12 to 25 percent

slopes .......................................................... 5338—Cochetopa loam, 25 to 65 percent

slopes .......................................................... 5339—Cochetopa loam, warm, 3 to 12 percent

slopes .......................................................... 5440—Cochetopa-Gothic complex, 10 to 25

percent slopes, extremely bouldery ............ 5541—Cochetopa-Gothic complex, 25 to 45

percent slopes, extremely stony .................. 55

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42—Cochetopa-Jerry complex, 3 to 15percent slopes, extremely stony .................. 56

43—Coldspring loam, moist, 1 to 12 percentslopes .......................................................... 57

44—Cowestglen sandy loam, 0 to 3 percentslopes .......................................................... 58

45—Coyet loamy sand, 3 to 12 percentslopes .......................................................... 58

46—Coyet loamy sand, 12 to 25 percentslopes .......................................................... 59

47—Coyet-Crestman, moist complex,20 to 50 percent slopes ............................... 59

48—Crago-Pensore-Grapit association,6 to 75 percent slopes ................................. 60

49—Cryoborolls, slumped, 15 to 50 percentslopes .......................................................... 61

50—Cushool fine sandy loam, 3 to 12percent slopes ............................................. 62

51—Cushool fine sandy loam, 12 to 25percent slopes ............................................. 63

52—Danavore-Waybe complex, 5 to 30percent slopes ............................................. 63

53—Davtone-Forsey complex, 12 to 35percent slopes, very stony ........................... 64

54—Deaver-Avalon complex, 5 to 45 percentslopes .......................................................... 65

55—Deaver-Chipeta complex, 3 to 35percent slopes ............................................. 66

56—Debone loam, 0 to 3 percent slopes .......... 6757—Detra-Cortyzack complex, 1 to 12

percent slopes ............................................. 6758—Diaflats-Fondillas complex, 2 to 15

percent slopes ............................................. 6859—Dranyon loam, 3 to 20 percent slopes ....... 6960—Dumps, mine .............................................. 6961—Ecklund-Tipperary complex, 1 to 12

percent slopes ............................................. 7062—Eghelm loamy fine sand, 0 to 3 percent

slopes .......................................................... 7063—Eghelm loamy sand, moist, 0 to 3

percent slopes ............................................. 7164—Emlin loam, 1 to 12 percent slopes ............ 7165—Emlin-Tymosling complex, 1 to 15

percent slopes, very bouldery ..................... 7266—Evanot loam, 1 to 12 percent slopes .......... 73

67—Evanot loam, 12 to 25 percent slopes ........ 7368—Evanot-Yamo complex, 3 to 20 percent

slopes .......................................................... 7469—Fenster-Thenipel complex, 3 to 12

percent slopes ............................................. 7570—Fluvaquents and Haplaquolls soils,

frequently flooded ........................................ 7671—Flygare loam, dry, 25 to 65 percent

slopes .......................................................... 7772—Foidel loam, cool, 3 to 25 percent

slopes .......................................................... 7773—Foidel loam, 25 to 65 percent slopes ......... 7874—Foidel, moist-Flygare-Skyway, moist

complex, 3 to 25 percent slopes .................. 7875—Fonce sandy loam, 1 to 8 percent

slopes .......................................................... 7976—Fonce gravelly sandy loam, 3 to 12

percent slopes, very stony ........................... 8077—Forelle loam, 3 to 12 percent slopes .......... 8178—Forelle loam, 12 to 25 percent slopes ........ 8179—Forelle-Evanot complex, 1 to 12 percent

slopes .......................................................... 8280—Forelle-Evanot complex, 12 to 25

percent slopes ............................................. 8281—Forelle-Obadia complex, 1 to 8 percent

slopes .......................................................... 8382—Forelle-Pinelli-Maysprings complex,

5 to 20 percent slopes ................................. 8483—Forsey-Libeg complex, 3 to 25 percent

slopes, very stony ........................................ 8584—Gebson, moist-Youga complex, 5 to 25

percent slopes, extremely stony .................. 8685—Giarch fine sandy loam, 0 to 3 percent

slopes .......................................................... 8786—Gracot-Maybell complex, 5 to 30

percent slopes ............................................. 8887—Gretdivid-Taffom-Abor complex,

10 to 30 percent slopes ............................... 8888—Grieves loamy fine sand, 1 to 12

percent slopes ............................................. 9089—Grieves loamy fine sand, 12 to 25

percent slopes ............................................. 9090—Grieves-Crestman complex, 10 to 40

percent slopes ............................................. 91

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91—Grieves-Yamo-Crestman association,3 to 45 percent slopes ................................. 92

92—Grimm-Ustic Torriorthents, shallowcomplex, 15 to 45 percent slopes................ 93

93—Gullied land ................................................ 9394—Hapney fine sandy loam, moist, 0 to 1

percent slopes ............................................. 9495—Haterton-Piezon complex, 3 to 12

percent slopes ............................................. 9496—Heathcoat stony loam, 1 to 6 percent

slopes, extremely stony ............................... 9597—Heathcoat-Clayburn complex, 5 to 35

percent slopes, very stony ........................... 9698—Herm-Fughes complex, 10 to 20

percent slopes, extremely bouldery ............ 9799—Hesperus fine sandy loam, dry, 2 to 15

percent slopes ............................................. 97100—Hesperus loam, 15 to 50 percent

slopes .......................................................... 98101—Hesperus loam, 3 to 25 percent

slopes, very stony ........................................ 98102—Holter-Detra complex, 3 to 25 percent

slopes, extremely stony ............................... 99103—Iles loam, 3 to 12 percent slopes ........... 100104—Ironco-Mulgon, dry complex, 25 to 50

percent slopes, extremely bouldery .......... 101105—Ironsprings loamy sand, 1 to 15

percent slopes ........................................... 102106—Ironsprings loamy sand, 15 to 30

percent slopes ........................................... 102107—Ironsprings-Maysprings-Gretdivid

complex, 10 to 20 percent slopes.............. 103108—Jerry-Cochetopa complex, 5 to 35

percent slopes ........................................... 104109—Joebas-Rock outcrop complex, 5 to 40

percent slopes ........................................... 105110—Kemmerer silty clay loam, 12 to 25

percent slopes ........................................... 105111—Kemmerer-Grapit complex, 15 to 65

percent slopes ........................................... 106112—Kemmerer-Moyerson complex,

20 to 40 percent slopes ............................. 107113—Kemmerer-Yamo complex, 5 to 30

percent slopes ........................................... 108

114—Lamphier fine sandy loam, 3 to 25percent slopes ........................................... 108

115—Lamphier fine sandy loam, 25 to 65percent slopes ........................................... 109

116—Lamphier-Jerry complex, 3 to 25percent slopes ........................................... 110

117—Lamphier-Jerry complex, 25 to 65percent slopes ........................................... 111

118—Lander loam, 0 to 3 percent slopes ........ 111119—Langspring sandy loam, 3 to 12

percent slopes ........................................... 112120—Layoint-Moosed-Berlake complex,

1 to 20 percent slopes ............................... 113121—Leaps clay loam, 3 to 15 percent

slopes, very stony ...................................... 114122—Leswill-Rogrube complex, 1 to 7

percent slopes ........................................... 114123—Lilsnake-Sandwash complex, 3 to 20

percent slopes ........................................... 115124—Losee-Thornburgh dry, complex,

25 to 65 percent slopes ............................. 116125—Massadona silty clay loam, 0 to 12

percent slopes ........................................... 117126—Massadona-Youngston moist,

complex, 1 to 8 percent slopes .................. 118127—Maudlin-Duffymont complex, 3 to 15

percent slopes, very stony ......................... 119128—Maybell sand, 3 to 12 percent slopes .... 119129—Maybell sand, 12 to 45 percent

slopes ........................................................ 120130—Maysprings coarse sandy loam,

3 to 12 percent slopes ............................... 120131—Maysprings-Gretdivid complex,

10 to 20 percent slopes ............................. 121132—Milren fine sandy loam, 0 to 10

percent slopes ........................................... 122133—Miracle-Coldspring complex, 3 to 12

percent slopes ........................................... 122134—Morapos loam, 3 to 12 percent slopes ... 123135—Morapos loam, 12 to 25 percentslopes .............................................................. 124136—Morapos-Pagoda complex, 2 to 12

percent slopes ........................................... 124

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137—Morset-Youga complex, 3 to 12percent slopes ........................................... 125

138—Moyerson-Rentsac complex, 15 to 45percent slopes ........................................... 126

139—Muggins gravelly sandy loam, 3 to 20percent slopes ........................................... 127

140—Ninot-Crago-Garlips complex, 15 to45 percent slopes ...................................... 128

141—Nortez, cool-Morapos complex, 3 to12 percent slopes ...................................... 129

142—Nortez, cool-Morapos complex, 12 to25 percent slopes ...................................... 131

143—Nunemaker clay loam, 3 to 12 percentslopes ........................................................ 131

144—Pagoda loam, 12 to 25 percentslopes ........................................................ 133

145—Pagoda clay loam, 1 to 12 percentslopes ........................................................ 134

146—Pavillion-Degater complex, 3 to 20percent slopes ........................................... 134

147—Peeler stony fine sandy loam, 5 to 25percent slopes, very stony ......................... 135

148—Pilotpeak-Grubrob complex, 1 to 12percent slopes ........................................... 136

149—Pinelli loam, 3 to 12 percent slopes ....... 136150—Pinelli clay loam, 3 to 15 percent

slopes ........................................................ 137151—Pinelli loam, dry, 3 to 8 percent

slopes ........................................................ 138152—Pinridge loam, 1 to 12 percent slopes .... 138153—Pricecreek clay loam, 0 to 4 percent

slopes ........................................................ 139154—Quealman sand, 0 to 3 percent

slopes ........................................................ 139155—Rencot-Duffymont complex, 1 to 25

percent slopes ........................................... 140156—Rentsac channery sandy loam, 25 to

65 percent slopes ...................................... 141157—Rentsac-Moyerson complex, 25 to 65

percent slopes ........................................... 141158—Rock outcrop-Earsman complex,

10 to 45 percent slopes ............................. 142159—Rock outcrop-Haploborolls complex,

10 to 40 percent slopes ............................. 143

160—Rock outcrop-Torriorthents complex,50 to 75 percent slopes ............................. 144

161—Rock River sandy loam, 0 to 3percent slopes ........................................... 144

162—Rock River sandy loam, 3 to 12percent slopes ........................................... 145

163—Rock River sandy loam, 12 to 25percent slopes ........................................... 145

164—Rock River-Taffom complex, 3 to 20percent slopes ........................................... 146

165—Rogrube complex, 3 to 12 percentslopes ........................................................ 147

166—Routt loam, 3 to 25 percent slopes ........ 148167—Routt-Cochetopa-Binco complex,

10 to 30 percent slopes, extremelystony .......................................................... 148

168—Ruedloff sandy loam, 1 to 8 percentslopes ........................................................ 149

169—Ruedloff-Dunul complex, 5 to 25percent slopes ........................................... 150

170—Ryan Park loamy sand, 3 to 15percent slopes ........................................... 151

171—Ryan Park sandy loam, 0 to 3 percentslopes ........................................................ 151

172—Ryan Park-Coyet complex, 5 to 25percent slopes ........................................... 152

173—Ryark-Powderwash complex, 2 to 15percent slopes ........................................... 153

174—Ryark-Maybell complex, 1 to 12percent slopes ........................................... 154

175—Sandwash-Langspring-Bastoncomplex, 1 to 6 percent slopes .................. 155

176—Schooner-Rock outcrop complex,5 to 45 percent slopes ............................... 156

177—Schooner-Tricera complex, 5 to 25percent slopes ........................................... 156

178—Simanni-Ruedloff complex, 1 to 10percent slopes ........................................... 157

179—Skyway fine sandy loam, dry, 15 to 75percent slopes ........................................... 158

180—Spool-Maybell complex, 5 to 40percent slopes ........................................... 159

181—Stunner sandy loam, 1 to 8 percentslopes ........................................................ 160

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182—Stunner, moist-Emlin complex, 1 to 12percent slopes ........................................... 160

183—Styers-Ironsprings-Mayspringscomplex, 10 to 20 percent slopes.............. 161

184—Styers-Pinelli-Taffom complex,10 to 25 percent slopes ............................. 162

185—Taffom sandy loam, 3 to 15 percentslopes ........................................................ 163

186—Talamantes loam, 0 to 6 percentslopes ........................................................ 164

187—Talamantes loam, 6 to 15 percentslopes ........................................................ 164

188—Talamantes loam, saline, 0 to 8percent slopes ........................................... 165

189—Tipper-Crustown complex, 10 to 40percent slopes ........................................... 166

190—Tipperary sand, 5 to 20 percentslopes ........................................................ 166

191—Tipperary loamy fine sand, 3 to 12percent slopes ........................................... 167

192—Tipperary-Willwood complex, 1 to 12percent slopes ........................................... 167

193—Tisworth fine sandy loam, 0 to 9percent slopes ........................................... 168

194—Tolman-Duffymont complex, 10 to 30percent slopes, extremely stony ...................... 169195—Torriorthents, 12 to 25 percent slopes .... 170196—Torriorthents-Baston complex, 3 to 12

percent slopes ........................................... 170197—Torriorthents-Rock outcrop,

sandstone complex, 25 to 75 percentslopes ........................................................ 171

198—Torriorthents-Rock outcrop, shalecomplex, 30 to 75 percent slopes.............. 172

199—Torriorthents-Torripsammentscomplex, 12 to 40 percent slopes .................... 172200—Tresano sandy loam, 3 to 12 percent

slopes ........................................................ 173201—Tresano-Hiatha-Kandaly association,

2 to 20 percent slopes ............................... 174202—Turzo loam, 0 to 5 percent slopes .......... 175203—Turzo loam, saline, 1 to 8 percent

slopes ........................................................ 175204—Typic Natrargids, 0 to 5 percent

slopes ........................................................ 176

205—Uffens fine sandy loam, 0 to 3 percentslopes ........................................................ 177

206—Ustorthents, frigid-Borolls complex,25 to 75 percent slopes ............................. 177

207—Vermillion-Langspring complex,3 to 25 percent slopes ............................... 178

208—Wallson-Tricera complex, 3 to 15percent slopes ........................................... 179

209—Weed sandy loam, 1 to 12 percentslopes ........................................................ 180

210—Willwood-Sheppard, cool complex,1 to 12 percent slopes ............................... 180

211—Willwood-Tipperary complex,12 to 40 percent slopes ............................. 181

212—Willwood-Tipperary, cobblysubstratum complex, 1 to 12 percentslopes ........................................................ 182

213—Winevada-Splitro complex, 3 to 25percent slopes ........................................... 183

214—Winevada-Splitro complex, 25 to 65percent slopes ........................................... 184

215—Winkleman clay loam, 0 to 3 percentslopes ........................................................ 184

216—Yamo loam, 3 to 15 percent slopes ........ 185217—Yamo loam, 15 to 30 percent slopes ...... 185218—Yellowwash-Piezon complex, 5 to 15

percent slopes ........................................... 186219—Youga loam, 3 to 15 percent slopes ....... 187220—Youga-Dinnen complex, 3 to 12

percent slopes ........................................... 187221—Youga-Gelkie-Clayburn, warm

complex, 25 to 45 percent slopes,extremely bouldery .................................... 188

222—Youngston loam, cool, 0 to 3 percentslopes ........................................................ 189

223—Youngston loam, well drained, 0 to 3percent slopes ........................................... 190

224—Zillion-Barkelew, moist-Grapitcomplex, 25 to 65 percent slopes,extremely stony ......................................... 190

225—Abracon-Solirec complex, 3 to 8percent slopes ........................................... 192

226—Arches-Mespun-Rock outcropcomplex, 4 to 40 percent slopes ................ 192

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227—Bankard family-Cameo complex,0 to 5 percent slopes ................................. 193

228—Bondman-Rock outcrop complex,5 to 40 percent slopes ............................... 194

229—Cameo loamy fine sand, 0 to 5percent slopes ........................................... 195

230—Cragnot-Pensore-Grapit association,6 to 75 percent slopes, very stony ............. 196

231—Green River-Fluvaquents complex,0 to 2 percent slopes ................................. 197

232—Lakebench-Strell complex, 5 to 30percent slopes ........................................... 198

233—Lakebench-Yampa complex, 5 to 30percent slopes, very stony ......................... 199

234—Mantlemine loam, 1 to 8 percentslopes ........................................................ 200

235—Mantlemine-Emlin complex, 1 to 12percent slopes ........................................... 200

236—Mido loamy fine sand, 3 to 12 percentslopes ........................................................ 201

237—Mikim complex, 1 to 4 percent slopes .... 202238—Milok fine sandy loam, 3 to 8 percent

slopes ........................................................ 203239—Milok-Solirec-Strych complex,

10 to 65 percent slopes, very stony ........... 203240—Milok-Strych complex, 3 to 25 percent

slopes, very stony ...................................... 205241—Pensore-Roto complex, 3 to 45

percent slopes, very stony ......................... 206242—Riverwash .............................................. 207243—Rizno-Windcomb-Anasazi complex,

3 to 25 percent slopes, extremely flaggy ... 207244—Rock outcrop-Hackling complex,

10 to 45 percent slopes, very stony ........... 208245—Rock outcrop, Torriorthents, and

Ustorthents soils, 25 to 75 percentslopes, rubbly ............................................ 209

246—Schoonover-Duffymont complex,3 to 25 percent slopes, rubbly ................... 210

247—Stout-Rock outcrop complex, 5 to 35percent slopes, very stony ......................... 211

248—Strych-Mellenthin complex, 3 to 45percent slopes, very bouldery ................... 212

249—Zillion-Yampa-Clyl complex, 25 to 65percent slopes, extremely flaggy ............... 213

250—Abracon loam, 3 to 8 percent slopes ..... 214251—Badland-Renegade complex,

50 to 80 percent slopes ............................. 215252—Bigtom-Namlot-Dokie association,

15 to 50 percent slopes ............................. 216253—Clapper gravelly loam, 2 to 25 percent

slopes ........................................................ 217254—Cliff sandy loam, 2 to 4 percent

slopes ........................................................ 218255—Clyl-Pinerid association, 8 to 40

percent slopes ........................................... 218256—Cortyzack-Diagulch complex, 3 to 25

percent slopes ........................................... 219257—Cortyzack-Duffymont complex,

3 to 25 percent slopes, rubbly ................... 220258—Cortyzack-Flynncove association,

3 to 25 percent slopes ............................... 221259—Denco-Gerst complex, 4 to 40 percent

slopes ........................................................ 222260—Dokie-Flynncove association, 25 to 50

percent slopes ........................................... 223261—Dokie-Namlot association, 15 to 70

percent slopes ........................................... 224262—Gompers very channery silt loam,4 to 25 percent slopes ..................................... 225263—Hanksville silty clay loam, 2 to 25percent slopes ................................................. 226264—Mikim loam, 3 to 15 percent slopes ....... 226265—Mikim silt loam, sodic, 1 to 4 percent

slopes ........................................................ 227266—Rock outcrop-Boxring-Tridell

complex, 10 to 50 percent slopes.............. 227267—Solirec-Abracon-Begay complex,

2 to 15 percent slopes ............................... 229268—Toliver-Rock outcrop association,

50 to 80 percent slopes ............................. 230269—Walknolls-Badland-Rock outcrop

complex, 25 to 50 percent slopes.............. 231270—Walknolls-Gilston association, 2 to 25

percent slopes ........................................... 232271—Water ...................................................... 233

Use and Management of the Soils .................... 235Interpretive Ratings.......................................... 235

Rating Class Terms ..................................... 235Numerical Ratings ....................................... 235

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Crops and Pasture ........................................... 235Yields per Acre ............................................ 236Land Capability Classification ..................... 237

Prime Farmland ............................................... 238Ecological Sites and Characteristic Native

Vegetation ................................................. 238Rangeland ....................................................... 239Forestland Productivity and Forestland

Understory Vegetation ............................... 259Recreation ....................................................... 259Wildlife ............................................................. 261

Wildlife Habitat ............................................. 261Engineering ..................................................... 262Building Site Development ............................... 263Sanitary Facilities ............................................. 264Construction Materials ..................................... 266Water Management ......................................... 266Agricultural Waste Management ...................... 267

Soil Properties .................................................... 271Engineering Index Properties .......................... 271Physical Properties .......................................... 272Chemical Properties ........................................ 273Soil Features .................................................... 274Water Features ................................................ 275

Classification of the Soils ................................. 277Soil Series and Their Morphology ................... 277Soil Taxons and Their Morphology .................. 277

Abor Series .................................................. 278Abracon Series ............................................ 278Adderton Series .......................................... 280Almy Series ................................................. 281Anasazi Series ............................................ 281Apmay Series .............................................. 283Arches Series .............................................. 283Avalon Series .............................................. 284Bankard Family ............................................ 285Barkelew Series .......................................... 286Baroid Series ............................................... 286Baston Series .............................................. 287Battlement Series ........................................ 288Beamton Series ........................................... 288Begay Series ............................................... 289Berlake Series ............................................. 290Bigtom Series .............................................. 291Bilhil Series .................................................. 292

Binco Series ................................................ 293Boltus Series ............................................... 294Bondman Series .......................................... 295Borollic Haplargids ...................................... 295Borollic Natrargids ....................................... 296Borolls ......................................................... 297Boxring Series ............................................. 298Brownsto Series .......................................... 299Bulkley Series .............................................. 299Cameo Series .............................................. 300Campspass Series ...................................... 301Canlodore Series ......................................... 302Carbol Series ............................................... 302Carmody Series ........................................... 303Castee Series .............................................. 303Chipeta Series ............................................. 304Chroder Series ............................................ 305Clapper Series ............................................. 306Clayburn Series ........................................... 307Cliff Series ................................................... 308Clifsand Series ............................................ 309Clyl Series ................................................... 310Cochetopa Series ........................................ 312Coldspring Series ........................................ 313Cortyzack Series ......................................... 314Cowestglen Series ...................................... 314Coyet Series ................................................ 315Cragnot Series ............................................ 316Crago Series ............................................... 317Crestman Series .......................................... 318Crustown Series .......................................... 318Cryoborolls .................................................. 319Cushool Series ............................................ 320Danavore Series .......................................... 320Davtone Series ............................................ 321Deaver Series .............................................. 321Debone Series ............................................. 322Degater Series ............................................ 323Denco Series ............................................... 324Detra Series ................................................ 325Diaflats Series ............................................. 325Diagulch Series ........................................... 326Dinnen Series .............................................. 327Dokie Series ................................................ 328Dranyon Series ............................................ 329

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Duffymont Series ......................................... 330Dunul Series ................................................ 330Earsman Series ........................................... 331Ecklund Series ............................................ 332Eghelm Series ............................................. 332Emlin Series ................................................ 333Evanot Series .............................................. 334Fenster Series ............................................. 335Fluvaquents ................................................. 335Flygare Series ............................................. 336Flynncove Series ......................................... 337Foidel Series................................................ 338Fonce Series ............................................... 339Fondillas Series ........................................... 340Forelle Series .............................................. 341Forsey Series .............................................. 341Fughes Series ............................................. 342Garlips Series .............................................. 343Gebson Series ............................................. 344Gelkie Series ............................................... 344Gerst Series ................................................ 345Giarch Series ............................................... 346Gilston Series .............................................. 347Gompers Series .......................................... 348Gothic Series ............................................... 349Gracot Series............................................... 350Grapit Series ............................................... 351Green River Series ...................................... 352Gretdivid Series ........................................... 353Grieves Series ............................................. 354Grimm Series .............................................. 354Grubrob Series ............................................ 355Hackling Series ........................................... 356Hanksville Series ......................................... 357Haplaquolls .................................................. 358Haploborolls ................................................ 359Hapney Series ............................................. 359Haterton Series ........................................... 360Heathcoat Series ......................................... 361Herm Series ................................................ 362Hesperus Series .......................................... 362Hiatha Series ............................................... 363Holter Series ................................................ 364Iles Series .................................................... 365Irigul Series ................................................. 365

Ironco Series ............................................... 366Ironsprings Series ....................................... 367Jerry Series ................................................. 367Joebas Series .............................................. 370Kandaly Series ............................................ 371Kemmerer Series ......................................... 371Lakebench Series ........................................ 372Lamphier Series .......................................... 373Lander Series .............................................. 374Langspring Series ....................................... 375Layoint Series .............................................. 375Leaps Series ............................................... 376Leswill Series .............................................. 377Libeg Series ................................................ 378Lilsnake Series ............................................ 379Losee Series ............................................... 379Mack Series ................................................. 380Mantlemine Series ....................................... 381Massadona Series ....................................... 382Maudlin Series ............................................. 383Maybell Series ............................................. 383Maysprings Series ....................................... 384Mellenthin Series ......................................... 385Mespun Series ............................................ 385Mido Series ................................................. 386Mikim Taxadjunct ......................................... 387Milok Series ................................................. 388Milren Series ............................................... 389Miracle Series .............................................. 390Moosed Series ............................................ 391Morapos Series ........................................... 391Morset Series .............................................. 392Moyerson Series .......................................... 393Muggins Series ............................................ 394Mulgon Series ............................................. 394Namlot Series .............................................. 395Ninot Series ................................................. 396Nortez Series............................................... 397Nunemaker Series ....................................... 398Obadia Series .............................................. 399Pagoda Series ............................................. 400Pavillion Series ............................................ 400Peeler Series ............................................... 401Pensore Series ............................................ 402Persayo Series ............................................ 403

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Piezon Series .............................................. 403Pilotpeak Series .......................................... 404Pinelli Series ................................................ 405Pinerid Series .............................................. 406Pinridge Series ............................................ 407Powderwash Series ..................................... 408Pricecreek Series ........................................ 409Quealman Series ......................................... 410Quilt Series .................................................. 410Rencot Series .............................................. 411Renegade Series ......................................... 412Rentsac Series ............................................ 413Rizno Series ................................................ 413Rock River Series ........................................ 414Rogrube Series ........................................... 415Roto Series .................................................. 416Routt Series ................................................. 417Ruedloff Series ............................................ 418Ryan Park Series ......................................... 418Ryark Series ................................................ 419Sandwash Series ........................................ 420Schooner Series .......................................... 421Schoonover Series ...................................... 421Sheppard Series .......................................... 422Simanni Series ............................................ 423Skyway Series ............................................. 423Solirec Series .............................................. 424Splitro Series ............................................... 425Spool Series ................................................ 426Stout Series ................................................. 426Strell Series ................................................. 427Strych Series ............................................... 428Stunner Series ............................................. 429Styers Series ............................................... 430Taffom Series ............................................... 431Talamantes Series ....................................... 431Thenipel Series ........................................... 432Thornburgh Series ....................................... 433Tipper Series ............................................... 433Tipperary Series .......................................... 434Tisworth Series ............................................ 435Toliver Series ............................................... 435Tolman Series .............................................. 437Torriorthents ................................................ 437Torripsamments ........................................... 438

Tresano Series ............................................ 438Tricera Series .............................................. 439Tridell Series ................................................ 440Turzo Series ................................................. 441Tymosling Series ......................................... 442Typic Natrargids ........................................... 443Uffens Series ............................................... 444Ustic Torrifluvents ........................................ 445Ustic Torriorthents ........................................ 445Ustorthents .................................................. 446Vermillion Series .......................................... 447Walknolls Series .......................................... 447Wallson Series ............................................. 448Waybe Series .............................................. 449Weed Series ................................................ 450Willwood Series ........................................... 451Windcomb Series ........................................ 451Winevada Series ......................................... 452Winkleman Series ....................................... 453Yamo Series ................................................ 453Yampa Series .............................................. 454Yellowwash Series ....................................... 455Youga Series ............................................... 456Youngston Series ........................................ 456Zillion Series ................................................ 457

Formation of the soils ........................................ 459Climate ............................................................. 459Living Organisms ............................................. 460Topography ...................................................... 460Parent Material ................................................ 461Time ................................................................. 461

References .......................................................... 463Glossary .............................................................. 465Tables .................................................................. 481

Table 1.--Temperature and precipitation .......... 483Table 2.--Freeze dates in spring and fall .......... 484Table 3.--Growing season ................................ 485Table 4.--Acreage and proportionate extent

of the soils ................................................. 486Table 5.--Land capability and yields per acre

of crops and pasture .................................. 491Table 6.--Prime farmland ................................. 510Table 7.--Ecological sites and characteristic

native vegetation ....................................... 511

14

Table 8.--Recreation--Camp areas, picnicareas, and playgrounds ............................. 589

Table 9.--Recreation--Golf fairways, pathsand trails, and off-road motorcyle trails ..... 632

Table 10.--Wildlife habitat ................................ 669Table 11.--Building site development--

Dwellings without basements, dwellingswith basements, and small commercialbuildings .................................................... 706

Table 12.--Building site development--Localroads and streets, shallow excavations,and lawns and landscaping ....................... 743

Table 13.--Sanitary facilities--Septic tankabsorption fields and sewagelagoons ...................................................... 788

Table 14.-- Sanitary facilities--Daily coverfor trench and area landfills ....................... 835

Table 15.--Construction materials--Potentialsource for gravel and sand ........................ 872

Table 16.--Construction materials .................... 907Table 17.--Water management ........................ 959Table 18.--Agricultural waste management:

Manure and food processing waste,Sewage sludge, and Wastewater .............. 996

Table 19.--Agricultural waste management:Overland flow, Rapid infiltration, andSlow rate treatment of wastewater .......... 1082

Table 20.--Engineering index properties ........ 1166Table 21.--Physical properties of the soils ..... 1261Table 22.--Chemical properties of the soils ... 1311Table 23.--Soil features .................................. 1348Table 24.--Water features............................... 1368Table 25--Classification of the soils ............... 1398

Issued 2004

15

This soil survey contains information that affects land use planning in this surveyarea. It contains predictions of soil behavior for selected land uses. The survey alsohighlights soil limitations, improvements needed to overcome the limitations, and theimpact of selected land uses on the environment.

This soil survey is designed for many different users. Farmers, ranchers, foresters,and agronomists can use it to evaluate the potential of the soil and the managementneeded for maximum food and fiber production. Planners, community officials,engineers, developers, builders, and home buyers can use the survey to plan landuse, select sites for construction, and identify special practices needed to ensureproper performance. Conservationists, teachers, students, and specialists inrecreation, wildlife management, waste disposal, and pollution control can use thesurvey to help them understand, protect, and enhance the environment.

Various land use regulations of Federal, State, and local governments may imposespecial restrictions on land use or land treatment. The information in this report isintended to identify soil properties that are used in making various land use or landtreatment decisions. Statements made in this report are intended to help the landusers identify and reduce the effects of soil limitations on various land uses. Thelandowner or user is responsible for identifying and complying with existing laws andregulations.

Great differences in soil properties can occur within short distances. Some soilsare seasonally wet or subject to flooding. Some are shallow to bedrock. Some are toounstable to be used as a foundation for buildings or roads. Clayey or wet soils arepoorly suited to use as septic tank absorption fields. A high water table makes a soilpoorly suited to basements or underground installations.

These and many other soil properties that affect land use are described in this soilsurvey. The location of each soil is shown on the detailed soil maps. Each soil in thesurvey area is described. Information on specific uses is given for each soil. Help inusing this publication and additional information are available at the local office of theNatural Resources Conservation Service or the Cooperative Extension Service.

Allen GreenState ConservationistNatural Resources Conservation Service

Foreword

http://www.nrcs.usda.gov/http://www.csrees.usda.gov/

17

General Nature of the Survey AreaMoffat County is in the northwest corner of

Colorado (fig. 1) and is the second largest county in the state. The county measures 91 miles east-west by 54 miles north-south and is over 3 million acres in size.Craig, the county seat, is located in the eastern partof the county near the Yampa River. At the time of thiswriting, the population of Craig is about 7,500; thepopulation of Moffat County is about 10,900.

The climate of the survey area ranges from arid tosubhumid and the precipitation ranges from 7 to over20 inches.

HistoryThe first recorded group of people known to have

inhabited the Moffat County area was the YampatikaUte Indians. The Uncompahgre Utes were the maingroup living in the area. They summered in the highmountain parks and wintered in the lower valleys ofthe Yampa River. They were primarily nomadichunters and gatherers. The area also wasoccasionally used by groups of Arapaho andShoshoni Indians who hunted or wintered in theYampa River drainage basin.

The first recorded explorers to enter the area,around 1776, were two Jesuit priests namedEscalante and Garcia. The Dominquez-Escalanteexpedition later recorded the natural resources of thearea.

Fifty years later, mountain men began to appear inthe area. One by the name of Ephraim Brown roamedand trapped much of the area. The area once knownas Browns Hole (now known as Browns Park) wasnamed for him.

In 1822, over 50 years after the first Spanishexpedition to the area, William Ashley organized amajor expedition to the Green River Country to helpopen the area to the fur trade. In 1844 John C.Frémont, with Kit Carson as guide, led an armyexpedition through Browns Hole and westward tomap the land and seek out possible routes for newtrails west.

In 1869 John Wesley Powell was commissioned tomap the Green River area. He noted on his journey

Soil Survey of

Moffat County Area, ColoradoBy Darrell Schroeder, Natural Resources Conservation Service

Fieldwork by Darrell Schroeder, Bob Grubb, Ed Horn, and Dave Alstatt, NaturalResources Conservation Service

Quality assurance of database and manuscript by Steve Park, Natural ResourcesConservation Service, Soil Data Quality Specialist, Southern Rocky MountainsRegional Soil Survey Office, Lakewood, Colorado

United States Department of Agriculture, Natural Resources Conservation Service,in cooperation with U. S. Department of the Interior—Bureau of Land Management,Colorado First Soil Conservation District, County of Moffat, and the ColoradoAgricultural Experiment Station

Figure 1.—Location of Moffat County Area in Colorado.

18 Soil Survey

through Browns Park that the area was of little valueand could only be developed through irrigation.

Although cattle were present in Browns Parkpreviously, development of the area was minimal dueto the presence of the Ute Indians and the lack ofreliable, easy transportation. In 1869, the Union Pacifictranscontinental railroad was completed throughWyoming. Soon cattlemen were moving into the areafrom the north, and by 1871 a major cattle industrywas established along the Little Snake, Green, andYampa Rivers. In 1889, the Craig Land and MercantileCompany was formed and 160 acres of land waspurchased to form the original townsite of the city ofCraig (fig. 2).

The Routt National Forest was established as aconservation effort in 1905, and by 1915 open grazingon lands within the forest boundaries was stopped andcontrolled grazing permits were issued. In 1934, theTaylor Grazing Service was created to control grazingon the rest of public domain lands in the area, thusvirtually ending the era of the open range in the Moffatarea.

In the second decade of the twentieth century, theMoffat Road Railroad came into Steamboat Springs in1909 and into Craig in 1913. For the first time cattle,sheep, wheat, hay, coal, and other commodities couldbe shipped directly to Denver, while goods andequipment from eastern factories could arrive directlyvia rail. This opened the land up even more to settlers.Because of numerous problems, the railroad wentbankrupt in 1912.

In 1911, Moffat County was divided from RouttCounty and Craig became the county seat of MoffatCounty.

One of the last major homestead efforts was madenorthwest of Craig in 1916. This was the Great DivideHomestead Colony Number One, developed by VolneyT. Hoggatt and promoted by the Denver Postnewspaper. Hundreds of settlers were lured into GreatDivide where they scratched out a living drylandfarming until the drought of the 1930s which causedmany of them to abandon their homesteads and leavethe area.

By the 1920s, the oil industry had developed to thepoint that oil fields such as Moffat, Iles, Danforth, andothers were in full production.

With the completion of the Moffat Tunnel in 1928,the major problem of reliable, quick, year-roundtransportation was solved. Craig began to develop as acity along with the expansion and further developmentof the county’s major industries. Since that time, thearea’s main uses and industries have been hay andwheat farming (with wheat declining rapidly at the timeof this writing), cattle ranching, coal mining, and oil

extraction. More recently founded industries includetourism and electric power plants.

Water Supply

There are three major rivers which flow through thesurvey area: the Yampa, the Little Snake, and theGreen Rivers. The survey area is dissected bynumerous creeks, most of which are intermittent andflow primarily during the spring snowmelt andoccasionally after a high intensity rainstorm. The othermajor perennial streams are Elkhead, Fortification, andSlater Creeks, and the Williams Fork River. The smallintermittent and perennial streams add significantamounts to the stream flowof the major rivers during the spring snowmelt.

The Yampa and Little Snake Rivers and the othermajor perennial streams supply water for irrigation. Thiswater is diverted from the streams and distributed bymeans of surface ditches.

The Yampa River also supplies domestic water tothe city of Craig and water to the Craig Power Plant forsteam generation of electricity.

The Yampa and Green Rivers also provide recreationin the forms of river rafting and fishing.

The Elkhead Reservoir is the only large reservoir inthe survey area. There are numerous small ponds andreservoirs that intercept surface runoff, spring flow, orstream flow from the small creeks. Most of these smallponds and reservoirs are dry during some parts of theyear, except those fed by springs and perennial

Figure 2.—Craig, Colorado is located on, and adjacent to,the Yampa River Valley. Major soils in the Craig area areBilhil clay loam, 0 to 3 percent slopes; Pinridge loam, 1to 12 percent slopes; Rock River sandy loam, 12 to 25percent slopes; and Yamo loam, 3 to 15 percent slopes.

Moffat County Area, Colorado 19

streams. These small ponds and reservoirs are themajor sources of water for livestock.

Industry and Transportation

Coal mining and the generation of electricity are themain industries in the survey area. Coal miningemploys about 13 percent and the generation ofelectricity about 10 percent of the workforce.Agriculture, although very important to the area, onlyemploys about 1 percent of the workforce. A largeportion of the workforce is employed by retail trade,construction, and services. The employment in thesesectors is dependent upon the number of peopleemployed in the main industries and upon the tourismin the area.

U.S.Highway 40 and Colorado Highway 13 are thetwo main highways in the survey area. The Denver, RioGrande and Western Railroad serves the area with amain line to Craig and spurs to local coal mines. Therailroad is the transportation used by the coal mines toship coal throughout the United States.

U.S. Highway 40 is one of the main trucktransportation routes in Western Colorado. It also is ascenic tourist route and brings tourists into and throughthe area.

Recreation

Moffat County offers a variety of year-round outdoorrecreational activities. Public access is availablethrough Routt and White River National Forests, theBureau of Land Management, and the ColoradoDivision of Wildlife lands.

In the winter months, Moffat County offers iceskating, cross-county skiing, snowshoeing, sleddingand snowmobiling. Swimming, river rafting, bicycling,hiking, fishing, camping, and picnicking can be enjoyedin many areas of Moffat County during the spring,summer, and fall months.

Large numbers of hunters from all over the UnitedStates come into the area each fall to hunt deer andelk. Pronghorn antelope, upland game birds, waterfowl,and rabbit hunting can also be enjoyed in MoffatCounty.

Browns Park National Wildlife Refuge and DinosaurNational Monument are favorite tourist attractions inwestern Moffat County.

The city of Craig has museums, swimming pools,parks and an eighteen-hole golf course.

The energy and mining industry offers free toursof some of Colorado’s largest coal-fired power plantsand coal mines.

Natural Resources

Estimates of coal reserves in Moffat County rangefrom 500 million to several billion tons. The depositsare mostly of a high volatility, low sulfur, bituminousgrade. Many deposits are at depths accessible forsurface strip mining, and the veins usually are thick.Moffat County also has large oil and natural gasreserves. The Sandwash Basin area is underlain bylarge oil shale deposits which have not beendeveloped.

Sand and gravel are available throughout most ofthe county along the terraces of the Yampa, LittleSnake, and Green Rivers, and within various locationsof pediment and alluvial deposits. Thick sequences oflimestone outcroppings occur near Juniper Mountain,Cross Mountain, Irish Canyon, Douglas Mountain, andTanks Peak.

Gold occurs in eluvial, alluvial, and sedimentarydeposits in the Wasatch formation of northeast MoffatCounty. The deposits consist of native free goldscattered irregularly throughout the area. The DouglasMountain area of western Moffat County containsdeposits of copper and iron ore. Copper mining hasoccurred sporadically in the area since the late 1800s.Uranium occurs in numerous deposits throughout thecounty, with average concentrations of the mineral.These deposits have been mined at various times inthe past.

Known geothermal resources in Moffat Countyconsist of the Craig Warm Water Well and Juniper HotSprings with temperatures near 100 degrees F.

With three major rivers flowing through the area,water is an available and valuable natural resourceproviding water for irrigation, domestic uses, and insteam generation of electricity.

There is a small amount of timber in lodgepole pinestands in the far northwestern corner of the county andfrom ponderosa pine stands on Douglas Mountain.Numerous stands of pinyon pine-juniper woodlandsoccur throughout the county and where harvested areused mainly for firewood and fence posts.

Agriculture

by William Lee Hill, District Conservationist, NRCS

Agriculture was started in the valleys and basins ofthe county. Agriculture is the area is diversified: itconsists of cow-calf, ewe-lamb, and yearling livestockoperations; irrigated and non-irrigated pasture and hay;and non-irrigated wheat, oats, and barley. Agriculture

20 Soil Survey

historically has been a mainstay of the area, but notalways a stable business concern.

Livestock enterprises are an important part ofagriculture in this area. Privately owned and Federally-administered rangeland provide grazing for cattle andsheep. Approximately 60 percent of the survey area isBureau of Land Management and U.S. Forest Serviceland. Livestock operations primarily consist of cow-calf, ewe-lamb, and yearlings. The cattle and sheepindustries are periodically upset by price fluctuationsfor their product.

Alfalfa and grass hay are the main irrigated crops.Most irrigation occurs on the Yampa River, FortificationCreek, and Little Snake River valleys. Most irrigation isdone by contour ditch flooding, border flooding, sideroll, or center pivot irrigation systems.

In the survey area, the main non-irrigated crop iswheat. Yearly variations in soil moisture andunpredictable markets have reduced acres in this landuse. Non-irrigated pasture and hayland acres are anincreasing land use.

The Colorado First Soil Conservation Districtcontains the Great Divide Soil Erosion District, whichwas the first Soil Conservation District in Colorado.Chartered on January 20, 1938, it was renamed theMoffat Soil Conservation District in 1957. The YampaSoil Conservation District was founded in 1947. Theconsolidation of the two districts took place on March31, 1991.

Physiography

The physiography of the survey area consists of twotypes: the river basins and the mountains.

There are four main rivers which drain the surveyarea: the Yampa, Little Snake, Green River, and WhiteRivers.

The Yampa River basin is in the central and east-central part of the survey area. This basin consists of anearly level broad valley floor and strongly rolling hillsdissected by numerous creeks. Most of the creeks areintermittent, flowing mainly during spring snowmeltrunoff. The Elkhead Creek, Fortification Creek, andWilliams Fork River are the other major perennialstreams.

The Little Snake River basin is in the northeast andnorth-central part of the survey area. This basinconsists of a nearly level valley floor and stronglyrolling hills dissected by numerous intermittent creeks.Steep breaks also are common in this basin.

The Green River basin is in the northwest part ofthe survey area. This basin consists of a nearly levelvalley floor, strongly rolling hills, and gently slopingbenches dissected by numerous intermittent creeks.Steep breaks also are common in this basin.

The White River basin is in the southwest part of thesurvey area. The White River does not flow through thesurvey area, but part of its drainageway lies within thesurvey area. This basin consists of strongly rolling hillsdissected by numerous small creeks and gullies.

There are six main mountain areas in the surveyarea: the Williams Fork and Elkhead Mountains, theDanforth Hills, the Cold Spring Mountains, the YampaPlateau, and the Douglas Mountains.

The Williams Fork Mountains and Danforth Hills arein the southeast and south central part of the surveyarea and are part of the Yampa River drainageway. Thismountain area consists of strongly sloping narrow tobroad plateaus dissected by very steep-sided gulchesdropping several hundred feet below the plateaus.

The Elkhead Mountains are in the northeast part ofthe survey area and are part of the Yampa River andLittle Snake River drainages. This mountain areaconsists of several high peaks surrounded by plateausand mountain ridges dissected by numerous creeks.

The Yampa Plateau, Douglas Mountains, and ColdSpring Mountains are in the western part of the surveyarea and are part of the Green River and White Riverdrainageways. These mountain areas consist of broadplateaus with occasional prominent peaks. Theplateaus are dissected by numerous creeks. Verysteep-sided canyons dropping several hundred feetbelow the plateaus also are common in the YampaPlateau area.

The elevation of the survey area ranges from 5,200to 9,700 feet, but the majority of the survey area liesbetween 6,000 and 7,500 feet.

Geology

The geology of the survey area consists mainlyof sedimentary formations. In small areas, loess orbasalt colluvial deposits cap the sedimentaryformations. Basalt formations occur in small areas.

The river basin areas, the Williams Fork Mountains,and the Danforth Hills areas consist mainly ofsandstone and shale formations. The valley floors ofthe rivers are deposits of alluvium derived from bothlocal and distant sources, and from many differentgeologic types. In small river basin areas, thesandstone and shale formations are capped by thinloess deposits. In the southeastern part of the WilliamsFork Mountains area and on Cedar Mountain, thesandstone and shale formations are capped withvarying amounts of basalt rocks.

The Yampa Plateau and Douglas Mountain areas aremainly massive hard sandstone and limestoneformations with small amounts of quartzite formations.The Elkhead Mountain area is sandstone and shale

Moffat County Area, Colorado 21

Figure 3.—Mining is an important resource for MoffatCounty residents. Stockpiling of topsoil forredistribution during reclamation can provide a goodmedium for reestablishing vegetation on the site oncemining is completed.

Figure 5.—Reclaimed mine areas, such as this one, provideforage for livestock and wildlife. They also reduce soilerosion.

Figure 6.—Irrigated hay and pasture are major crops grownin Moffat County. One of the main areas for hayproduction occurs here along the Yampa River.

Figure 4.—Wildlife is an important resource for the MoffatCounty area. Summer grazing areas, along with foragein winter range, are important to maintaining wildlifenumbers and improving the condition of variousspecies.

22 Soil Survey

Figure 8.—Snow is an important source of water in MoffatCounty. Soil moisture is increased in areas where snowcollects in depressions or is trapped by shrubs such assagebrush. Note the snow captured by the sagebrushin the foreground. Increased soil moisture results in anincrease in forage production.

Figure 7.—Shown is an example of some of the diversetopography located in the survey area. Soils on thevalley floor are Yellowash-Piezon complex, 5 to 15percent slopes and Haterton-Piezon complex, 3 to 12percent slopes. The mapping unit on the sideslopes isTorriorthents-Rock outcrop, shale complex, 30 to 75percent slopes. Soils on the plateau are Brownsto-Castee complex, 3 to 25 percent slopes.

Figure 9—A graph of the average monthly total precipitation for Maybell. It shows that precipitation is evenly distributedthroughout the year with an exception of increases in April and May and September, October, and November.

Moffat County Area, Colorado 23

formations capped with varying depths of colluvialdeposits of basalt rocks. There also are small areas ofbasalt formations.

ClimatePrepared by the Natural Resources Conservation Service

National Water and Climate Center, Portland, Oregon.

Climate tables are created from climate stations atDinosaur National Monument and at Maybell, Colorado.In the following narrative, information also is extractedfrom climate stations Craig 4SW and Hamilton, also inMoffat County. A new mean annual precipitation mapproduced for the NRCS by Oregon State Universityusing the PRISM modeling system also was used inproducing this narrative.

Thunderstorm days, relative humidity, percentsunshine, and wind information are estimated fromFirst Order station Grand Junction, Colorado.

Table 1 gives data on temperature and precipitationfor the survey area as recorded at these two climatestations in the period 1971 to 2000. Table 2 showsprobable dates of the first freeze in fall and the lastfreeze in spring. Table 3 provides data on the length ofthe growing season.

In winter, average temperatures are 24.0 and 19.2degrees F at Dinosaur and Maybell, respectively. Theaverage daily minimum temperatures in winter are 12.5and 3.7 degrees at these two stations. The lowesttemperatures on record were –29 degrees at Dinosauron December 22, 1990; and –61 degrees at Maybell onFebruary 1, 1985. In summer, average temperaturesare 70.5 degrees at Dinosaur and 64.0 degrees atMaybell. The average daily maximum temperatures are87.7 degrees and 84.0 degrees, respectively. Thehighest temperatures ever recorded in the Moffat areawere 103 degrees F. at Dinosaur on July 7, 1989, and102 degrees F. at Maybell on July 21, 1960.

Growing degree days are shown in Table 1. They areequivalent to “heat units”. During the month, growingdegree days accumulate by the amount that theaverage temperature each day exceeds a basetemperature (40 degrees F). The normal monthlyaccumulation is used to schedule single or successiveplantings of a crop between the last freeze in springand the first freeze in fall.

Average annual total precipitation over the county isdependent upon elevation and east-west location. Ingeneral, precipitation increases from west to eastacross Moffat County, with the lowest elevationlocations along the Green and lower Vermillion Riversreceiving only about 9 inches of annual precipitation.Dinosaur climate station receives 11.78 inches

annually, while 13.25 inches falls at Maybell, 16.39inches at Craig, and 19.45 inches at Hamilton. Theannual precipitation map indicates between 10 and 15inches over most of the western half of the county,with higher elevations receiving up to 18-20 inches. Inthe eastern half of the county annual precipitation isgenerally between 12 and 18 inches, with higherelevations receiving between 18 and 22 inches. Thehighest elevation of the county in the Routt NationalForest near the Routt County border receives nearly 50inches of annual precipitation. Most precipitation athigher elevations comes in the winter and spring, whileat lower elevations about 50 percent comes during thisperiod. The growing season is quite short over thecounty, with the longest growing season in the lowerwestern valleys. For instance, at Dinosaur the growingseason is from May through September, and duringthis period about 5.3 inches of precipitation falls,which is about 45 percent of the annual total atDinosaur. The heaviest 1-day precipitation amountsduring the periods of record were 1.98 inches atDinosaur on August 2, 1968, and 2.46 inches atMaybell on April 22, 1985. Thunderstorms occur onabout 30-35 days each year, and most occur betweenmid-June and early September.

Average seasonal snowfall over the county also ishighly dependent upon elevation. At Dinosaur theaverage annual total is 44.9 inches, while it is 66.3inches at Maybell and 78.2 inches at Craig. The higherterrain receives between 80 and 120 inches ofsnowfall per year, and highest elevations in the easternpart of the county likely receive over 200 inches. Thegreatest snow depth at any one time during the periodof record at Dinosaur was 23 inches recorded onFebruary 9, 1985; at Maybell the greatest snow depthwas 29 inches on December 26, 1983. At Hamilton, therecord is 39 inches on the ground on Christmas Eve,1948. On average, about 70 days per year have atleast 1 inch of snow on the ground at Dinosaur andMaybell, while about 80 days per year is common atCraig, and at higher elevations between 4 and 6months of the year have snow on the ground. Theheaviest 1-day snowfalls on record were: 14.0 inchesat Dinosaur on November 21, 1983; 15.5 inches atMaybell on January 29, 1980; and 26.0 inches atHamilton on December 30, 1951.

The average relative humidity in mid-afternoon isabout 20 percent in July and about 60 percent inJanuary. Humidity is higher at night, and the average atdawn is about 60 percent in the summer and 80percent in the winter. The sun shines about 70-80percent of the time in summer and around 55-60percent of the time in the winter. The prevailing wind isfrom the west in most months. Highest average speeds

24 Soil Survey

are in the winter and spring, averaging around 10 mph.However, winds are highly dependent upon elevationand exposure.

How This Survey Was MadeThis survey was made to provide information about

the soils and miscellaneous areas in the survey area.The information includes a description of the soils andmiscellaneous areas and their location and adiscussion of their suitability, limitations, andmanagement for specified uses. Soil scientistsobserved the steepness, length, and shape of theslopes; the general pattern of drainage; the kinds ofcrops and native plants; and the kinds of bedrock. Theydug many holes to study the soil profile, which is thesequence of natural layers, or horizons, in a soil. Theprofile extends from the surface down into theunconsolidated material in which the soil formed. Theunconsolidated material is devoid of roots and otherliving organisms and has not been changed by otherbiological activity.

The soils and miscellaneous areas in the surveyarea are in an orderly pattern that is related to thegeology, landforms, relief, climate, and naturalvegetation of the area. Each kind of soil andmiscellaneous area is associated with a particular kindof landform or with a segment of the landform. Byobserving the soils and miscellaneous areas in thesurvey area and relating their position to specificsegments of the landform, a soil scientist develops aconcept or model of how they were formed. Thus,during mapping, this model enables the soil scientist topredict with a considerable degree of accuracy the kindof soil or miscellaneous area at a specific location onthe landscape.

Commonly, individual soils on the landscape mergeinto one another as their characteristics graduallychange. To construct an accurate soil map, however,soil scientists must determine the boundaries betweenthe soils. They can observe only a limited number ofsoil profiles. Nevertheless, these observations,supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient toverify predictions of the kinds of soil in an area and todetermine the boundaries.

Soil scientists recorded the characteristics of thesoil profiles that they studied. They noted soil color,texture, size and shape of soil aggregates, kind andamount of rock fragments, distribution of plant roots,reaction, and other features that enable them toidentify soils. After describing the soils in the survey

area and determining their properties, the soilscientists assigned the soils to taxonomic classes(units). Taxonomic classes are concepts. Eachtaxonomic class has a set of soil characteristics withprecisely defined limits. The classes are used as abasis for comparison to classify soils systematically.Soil taxonomy, the system of taxonomic classificationused in the United States, is based mainly on the kindand character of soil properties and the arrangement ofhorizons within the profile. After the soil scientistsclassified and named the soils in the survey area, theycompared the individual soils with similar soils in thesame taxonomic class in other areas so that theycould confirm data and assemble additional data basedon experience and research.

While a soil survey is in progress, samples of someof the soils in the area generally are collected forlaboratory analyses and for engineering tests. Soilscientists interpret the data from these analyses andtests as well as the field-observed characteristics andthe soil properties to determine the expected behaviorof the soils under different uses. Interpretations for allof the soils are field tested through observation of thesoils in different uses and under different levels ofmanagement. Some interpretations are modified to fitlocal conditions, and some new interpretations aredeveloped to meet local needs. Data are assembledfrom other sources, such as research information,production records, and field experience of specialists.For example, data on crop yields under defined levelsof management are assembled from farm records andfrom field or plot experiments on the same kinds ofsoil.

Figure 10.—Early in the making of this survey, a soil scientistextracts a core sample in an area of map unit 79,Forelle-Evanot complex, 1 to 12 percent slopes. Thesesoils are used for dryland wheat production.

Moffat County Area, Colorado 25

Predictions about soil behavior are based not onlyon soil properties but also on such variablesas climate and biological activity. Soil conditions arepredictable over long periods of time, but they arenot predictable from year to year. For example, soilscientists can predict with a fairly high degree ofaccuracy that a given soil will have a high water tablewithin certain depths in most years, but they cannotpredict that a high water table will always be at aspecific level in the soil on a specific date.

After soil scientists located and identified thesignificant natural bodies of soil in the survey area,

they drew the boundaries of these bodies on aerialphotographs and identified each as a specific map unit.Aerial photographs show topographic features, trees,buildings, fields, roads, and rivers, all of which help inlocating boundaries accurately.

Descriptions, names, and delineations of soils inthis soil survey do not fully agree with those on soilmaps for adjacent survey areas. Differences are theresult of better knowledge of soils, modifications inseries concepts, intensity of mapping, or the extentof soils within the survey area.

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Detailed Soil Map Units

The map units delineated on the detailed soilmaps in this survey represent the soils ormiscellaneous areas in the survey area. The map unitdescriptions in this section, along with the maps, canbe used to determine the suitability and potential of aunit for specific uses. They also can be used to planthe management needed for those uses.

A map unit delineation on a soil map representsan area dominated by one or more major kinds ofsoil or miscellaneous areas. A map unit is identifiedand named according to the taxonomic classificationof the dominant soils. Within a taxonomic class thereare precisely defined limits for the properties of thesoils. On the landscape, however, the soils arenatural phenomena, and they have the characteristicvariability of all natural phenomena. Thus, the rangeof some observed properties may extend beyond thelimits defined for a taxonomic class. Areas of soils ofa single taxonomic class rarely, if ever, can bemapped without including areas of other taxonomicclasses. Consequently, every map unit is made upof the soils or miscellaneous areas for which it isnamed and some minor components that belong totaxonomic classes other than those of the majorsoils.

Most minor soils have properties similar to thoseof the dominant soil or soils in the map unit, and thusthey do not affect use and management. These arecalled noncontrasting, or similar, components. Theymay or may not be mentioned in a particular mapunit description. Other minor components, however,have properties and behavioral characteristicsdivergent enough to affect use or to require differentmanagement. These are called contrasting, ordissimilar, components. They generally are in smallareas and could not be mapped separately becauseof the scale used. Some small areas of stronglycontrasting soils or miscellaneous areas areidentified by a special symbol on the maps. Thecontrasting components are mentioned in the mapunit descriptions. A few areas of minor componentsmay not have been observed, and consequently theyare not mentioned in the descriptions, especiallywhere the pattern was so complex that it was

impractical to make enough observations to identifyall the soils and miscellaneous areas on thelandscape.

The presence of minor components in a map unitin no way diminishes the usefulness or accuracy ofthe data. The objective of mapping is not to delineatepure taxonomic classes but rather to separate thelandscape into landforms or landform segments thathave similar use and management requirements. Thedelineation of such segments on the map providessufficient information for the development of resourceplans. If intensive use of small areas is planned,however, onsite investigation is needed to define andlocate the soils and miscellaneous areas.

An identifying symbol precedes the map unit namein the map unit descriptions. Each descriptionincludes general facts about the unit and gives theprincipal hazards and limitations to be considered inplanning for specific uses.

Soils that have profiles that are almost alike makeup a soil series. Except for differences in texture ofthe surface layer, all the soils of a series have majorhorizons that are similar in composition, thickness,and arrangement.

Soils of one series can differ in texture of thesurface layer, slope, stoniness, salinity, degree oferosion, and other characteristics that affect their use.On the basis of such differences, a soil series isdivided into soil phases. Most of the areas shown onthe detailed soil maps are phases of soil series. Thename of a soil phase commonly indicates a featurethat affects use or management. For example,Adderton loam is a phase of the Adderton series.

Some map units are made up of two or moremajor soils or miscellaneous areas. These map unitsare complexes, associations, or undifferentiatedgroups.

A complex consists of two or more soils ormiscellaneous areas in such an intricate pattern or insuch small areas that they cannot be shownseparately on the maps. The pattern and proportionof the soils or miscellaneous areas are somewhatsimilar in all areas. Map unit 6, Avalon-Mack complex,1 to 12 percent slopes is an example.

28 Soil Survey

An association is made up of two or moregeographically associated soils or miscellaneousareas that are shown as one unit on the maps.Because of present or anticipated uses of the mapunits in the survey area, it was not consideredpractical or necessary to map the soils ormiscellaneous areas separately. The pattern andrelative proportion of the soils or miscellaneous areasare somewhat similar. Map unit 48, Crago-Pensore-Grapit association, 6 to 75 percent slopes is anexample.

An undifferentiated group is made up of two ormore soils or miscellaneous areas that could bemapped individually but are mapped as one unitbecause similar interpretations can be made for useand management. The pattern and proportion of thesoils or miscellaneous areas in a mapped area arenot uniform. An area can be made up of only one ofthe major soils or miscellaneous areas, or it can bemade up of all of them. Map unit 70, Fluvaquents andHaplaquolls soils, frequently flooded is anundifferentiated group in this survey area.

This survey includes miscellaneous areas. Suchareas have little or no soil material and support littleor no vegetation. Map unit 8, Badland, is an example.

Table 4 gives the acreage and proportionate extentof each map unit. Other tables give properties of thesoils and the limitations, capabilities, and potentialsfor many uses. The Glossary defines many of theterms used in describing the soils or miscellaneousareas.

1—Abor silty clay loam, 12 to 25 percentslopes

Map Unit Setting

Major Land Resource Area: 34Elevation: 6,300 to 7,000 feet (1,920 to 2,134 meters)Mean annual precipitation: 13 to 15 inches (330 to

381 millimeters)Mean annual air temperature: 42 to 45 degrees F.

(5.6 to 7.0 degrees C.)Freeze-free period: 75 to 95 days

Map Unit Composition

Abor and similar soils: 85 percentMinor components: 15 percent

Component Descriptions

Abor soils

Landform: HillslopesParent material: Residuum derived from shale

Slope: 12 to 25 percentDepth to restrictive feature: 20 to 40 inches to

bedrock (paralithic)Drainage class: Well drainedSlowest permeability: .001 to .06 in./hr. (very slow)Available water capacity: About 5.7 inches (low)Shrink-swell potential: About 7.5 percent (high)Runoff class: Very highCalcium carbonate maximum: About 4 percentGypsum maximum: NoneSalini