United States Department of Agriculture
Natural Resources Conservation Service		 Idaho Go to Accessibility Information
Skip to Page Content
 Scenic Photo of Idaho
 

Soil Survey of St. Joe Area, Parts of Benewah and Shoshone Counties, Idaho


USDA – NRCS, Soil Survey Office
7830 Meadowlark Way, Suite C-1
Coeur d’Alene, ID 83814
208-762-4939 Ext. 110

State survey area: ID608
Soil survey area: 721,800 total acres (1,128 square miles)

St. Joe Soil Survey completed in 1993: mapping completed in 1992; database in progress

GENERAL: The survey area is located in the central part of the Idaho panhandle. The survey area includes the eastern half of Benewah County and the central and southern parts of Shoshone County. It is bounded on the north and east by the Idaho Panhandle National Forest and on the southwest by the Clearwater National Forest. The St. Joe area consists of forested mountainous or hilly terrain and narrow valleys. The Coeur d’Alene Mountains are in the northern part of the survey area and the St. Joe Mountains are in the southern part. The most prominent valleys are the St. Joe and the Coeur d’Alene River valleys. Most of the survey area is woodland; however, a significant amount of acreage is used for hay and pasture.

Elevation ranges from about 2,140 feet above sea level along the major river drainages to more than 6,000-feet at some of the mountain peaks. The total annual precipitation is about 30 inches, of which 33 percent falls in April through September. The average seasonal snowfall is about 55 inches. The average temperature in winter is 29 degrees F. In summer, the average temperature is 65 degrees.

SOILS: The soils in the St. Joe area formed from residual, colluvial, alluvial and loessial parent material. The mountains are mainly residual and colluvial material derived from Precambrian metasedimentary rocks. The canyons and escarpments are mainly residual and colluvial material derived from igneous rocks that formed from Miocene-age basalt flows. Most soils formed in residuum and colluvium contain a high percentage of rock fragments and also have varying amounts of surficial loess and volcanic ash deposited during the late Pleistocene and Holocene Epochs (USDA, 1984). The volcanic ash is predominantly silt-sized material and originated from many active volcanoes in the Cascade Range, with the greatest contribution of ash coming from Mt. Mazama approximately 6,700 years ago. Soils on dissected terraces formed in varying amounts of loess, old alluvial deposits and volcanic ash.  Soils in the river valleys and stream terraces formed mainly in relatively recent silty alluvial deposits.

Major soils of the survey area include the following:
MODERATELY STEEP TO VERY STEEP, WELL DRAINED SOILS ON MOUNTAINS

  1. AHRS-PINECREEK-LOTUSPOINT: moderately deep and very deep, steep and very steep, well-drained soils on mountains and mountain breaklands
  2. HONEYJONES-AHRS: very deep, moderately steep to very steep, soils on mountains
  3. LATOUR-VAYWOOD-RUBBLE land: very deep, moderately steep to very steep, soils and rubble land on mountains and ridge at high elevations
  4. JACOT-KEELER-GARVESON: very deep, moderately steep to very steep, soils on mountains and foothills
  5. NAKARNA-FLEWSIE: deep and very deep, moderately steep to very steep, soils on mountains and foothills
  6. BOULDERCREEK-MARBLECREEK: very deep, moderately steep to very steep, soils on mountains

MODERATELY STEEP TO VERY STEEP, MODERATELY WELL DRAINED AND WELL DRAINED SOILS ON DISSECTED TERRACES AND FOOTHILLS

  1. HUGUS-TIGLEY-HOBO: very deep, moderately steep to very steep, soils on dissected terraces and foothills

STEEP AND VERY STEEP, WELL DRAINED SOILS ON BASALT TERRACE ESCARPMENTS AND CANYONSIDES

  1. AGATHA-DORB-BOBBITT: moderately deep and deep, steep and very steep soils on basalt terrace escarpments and canyonsides

UNDULATING TO STEEP, MODERATELY WELL DRAINED AND WELL DRAINED SOILS ON OLD ALLUVIAL AND BASALT TERRACES

  1. HELMER-SLY-HOBO: shallow to a fragipan and very deep, undulating to steep, moderately well-drained and well-drained soils on old alluvial and basalt terraces
  2. REGGEAR: moderately deep to a fragipan, undulating to moderately steep, moderately well-drained soils on basalt terraces

LEVEL TO UNDULATING, VERY POORLY DRAINED TO SOMEWHAT POORLY DRAINED SOILS ON VALLEY FLOORS, FLOOD PLAINS, LOW  STREAM TERRACES AND DRAINAGEWAYS

  1. MIESEN-RAMSDELL-BELLSLAKE: very deep, level to undulating, very poorly drained to somewhat poorly drained soils on flood plains and low stream terraces
  2. CLARKIA-POKEY-TYPIC FLUVAQUENTS: very deep, level to undulating, very poorly drained to somewhat poorly drained soils on flood plains and low stream terraces
  3. AQUIC UDIFLUVENTS-UDARENTS-SLICKENS: very deep, level to undulating, somewhat poorly drained soils and areas of Slickens on flood plains, low stream terraces and valley floors
     

< Back to Soil Survey Status