PERMFILE122249

• Permit No: M1980038
• IBM Index Class Name: Permit File
• Doc Name: LIMITED IMPACT 110 & SPECIAL 10 DAY 111 PERMIT APPLICATION FORM
• Media Type: D
• Archive: No

The General Soil Map was prepared by delineating eight mapping units that
differ from each other in the kinds of soil that are present. The soils
in each mapping unit are associated and form patterns that are repeated from
place to place. They were defined and described according to requirements
imposed by the map scale and criteria from the Comprehensive System of
Soil Classification, adopted in January 1965. The composition of the units
along with related characteristics and interpretative information are shown
in Table 1. Readers interested in more detailed information about the
classification system should consult technical publications. 1/, ?/
Acreage distribution of mapping units and percent that each occupies is
given in Table 2. Composition and related characteristics of each soil
mapping unit are given in the following brief narrative descriptions.
Soil Mapping Unit 1: Licht-colored soils of the deserts
This unit is in Disappointment Valley, mostly in San Miguel County, but a
small part extends into Dolores County. This unit is one of the least
extensive in the basin. Water intake is slow and runoff is rapid. Erosion
is moderate to severe and sediment yield is in the range of 1.0-3.0 acre-
feet per square mile per year.
The landscape is characterized by a wide oblong valley with rolling shale
hills on the north and east and steep barren shale hills to the south-
east. There are many intermittent drainageways into Disappointment Creek.
Most of these drainageways are eroded to depths of 10 to 20 feet and widths
of 10 to 50 feet. A sparse cover of shadscale is present with some sagebrush,
rabbitbrush, and greasewood along the drainageways. On the upper reaches
of the valley there are a few pinyon-juniper.
There are three major groups of sails in this unit. Shallow soils derived
from Mancos Shale make up about 50 percent of the unit. They have light-
colored, calcareous, surface layers, are low in organic matter and have fine
and moderately fine textures. These soils are on rolling hills, mainly
on the north and east side of Disappointment Creek. Another 35 percent of
the unit consists of deep and moderately deep fine textured alluvial soils.
These soils are along Disappointment Creek. They usually have light-colored
surface layers although in the upper reaches of the valley they become
darker. The soils are moderately saline-alkali and have a slow permeability
rate. The remaining 15 percent of the unit consists of reddish-brown,
moderately deep soils on small terraces, mainly on the south and west side
of Disappointment Creek. Surface layers are light-colored and the
permeability rate is moderate.
1/ Soil Survey Staff, SCS, USDA
"Soil Classification, a Comprehensive System 7th Approximation,"
1960 and as amended through October 1966.
2/ Aandahl, Andrew R.
"The First Comprehensive Soil Classification System" Journal of
Soil and Water Conservation 20:243-246, 1965.