HomeMy WebLinkAbout20012774 Soils Report
Tuesday 24 April 2001
By: Bradford Janes
Professional Forester
Soil Scientist
Subject: Varra Companies, Inc.
North Metro Distribution Center
S/2NW/4; Section 25; Township 1 North; Range 68 West; and,
N/2SW/4; Section 25; Township 1 North;Range 68 West; all in the
6`"P.M.; Weld County, Colorado.
Weld County Use by Special Review Application
The information derived for this report included on-site inspections, and the Weld
County, Colorado Soil Survey, Southern Part, with appropriate portions extracted and
included at the back of this report.
Three soil units intersect the parcel:
1. Unit 66 -Ulm clay loam, 0-3 percent slopes.
2. Unit 79—Weld Loam, 1-3 percent slopes.
3. Unit 83 —Wiley-Colby complex, 3-5 percent slopes.
The majority of soil impacted by the proposed use is Unit 79. Unit 83 is only marginally
encountered, while only a minor portion of Unit 66 will be encountered. Regardless, all
three soil properties are described as deep, well drained soils, however, overall surface
depth of the A profile ranges from 0 to 11 inches, or approximately 4 to 6 inches of
average depth depending upon slope, management practices, etc.
MI soils encountered have expansive clays with shrink swell potentials that appear to
increase with depth, and depending upon the subsoil encountered. Septic and Structures
should not be considered on the property without proper engineering from a qualified
professional engineer(Please refer to the included Table 6—Building Site Development,
and Table 7— Sanitary Facilities, of the Soil Survey). The use of engineered features for
septic and structures is either included or proposed in the USR submittal. Further,
structures and placement on soils where strength of the underlying material or
embankment could fail, should be considered by a qualified engineer.
In general, all slopes lacking structures should be able to be stabilized if slopes do not
exceed 3h:1 v. This includes waterways for conveyance of storm water. In general,
slopes will not exceed two percent over the developed ground, with the possible
exception of back slopes necessary to establish the lower grades. R
t
Addendum C
Varra Companies, Inc. —North Metro Distribution Center
Section 25; Township 1 North; Range 65 West; 6`h P.M.; Weld County Colorado
2001-2774
Since grades will be lower than existing percent slopes over the potential water ways,
erosion potential should be considerably less than that generally described in Table 9—
Water Management, of the Soil Survey. Properly vegetated grassed water ways should
work well and in a stable condition with a potential for additional stabilization methods,
such as hay bale dissipaters, or other conservation measures, should conditions warrant.
Flooding is not a reported hazard, either in this Survey(Table 14— Soil and Water
Features), or by FEMA maps on file with Weld County Department of Planning Services.
The location does not have a high water table, neither is there any reported risk to
subsidence due to potential underlying coal seams(refer to Terracon report of 19 January
2001, following).
Overall production is suited to crops, however, the capability classes identified, along
with the attending soil units, on Plot Plan, page 1 of 4, Facility Layout, suggests severe
limitations as to plant selection, with an emphasis on management of established
conservation practices to prevent plant failures, erosion, etc.
The parcel soils do not display a potential for wildlife habitat potential, but are readily
reclaimable with care, and well adapted to the establishment of native grasses. The soils
are also suitable for the establishment of trees. The proposed Landscape Plan identified
under Addendum D, following this report, is developed with the knowledge of the
attending soil classifications.
2
WELD COUNTY, COLORADO, SOUTHERN PART 43
livestock and wildlife share the range. Livestock watering ing. The grass selected should meet the seasonal require-
_
facilities also are utilized by various wildlife species. The merits of livestock. It can be seeded into a clean, firm
cropland areas provide favorable habitat for pheasant and sorghum stubble, or it can be drilled into a firm prepared
mourning dove. Many nongame species can be attracted seedbed. Seeding early in spring has proven most success-
by establishing areas for nesting and escape cover. ful.
The underlying shale is the most limiting feature of Windbreaks and environmental plantings of trees and
this soil. Neither septic tank absorption fields nor sewage shrubs commmonly grown in the area are generally well
lagoons function properly. In places the underlying shale suited to- this soil. Cultivation to control competing
has high shrink-swell potential. Environmental-and beau- vegetation should be continued for as many years as
tification plantings of trees and shrubs can be difficult to possible following planting.Trees that are best suited and
establish. Capability subclass We irrigated, VIe nonir- have good survival are Rocky Mountain juniper, eastern
rigated; Loamy Plains range site. redcedar, ponderosa pine, Siberian elm, Russian-olive, and
66—Ulm clay loam, 0 to 3 percent slopes. This is a hackberry. The shrubs best suited are skunkbush sumac,
deep, well drained soil on plains at elevations of 5,075 to lilac, Siberian peashrub,and American plum.
5,200 feet. It formed in alluvial and eolian sediments from Wildlife is an important secondary use of this soil. The
shale. Included in mapping are small areas of soils that cropland areas provide favorable habitat for ring-necked
have shale between 40 and 60 inches. Also included are pheasant and mourning dove. Many nongame species can
small areas of soils where the surface layer and subsoil be attracted by establishing areas for nesting and escape
have been recharged with lime from irrigation. cover. For pheasants, undisturbed nesting cover is essen-
Typically the surface layer of this Ulm soil is brown tial and should be included in plans for habitat develop-
clay loam about 5 inches thick. The subsoil is brown and ment, especially in areas of intensive agriculture. Range-
pale brown clay about 14 inches thick. The substratum to land wildlife, for example, the pronghorn antelope, can be
a depth of 60 inches is clay and clay loam, attracted by developing livestock watering facilities,
Permeability is slow. Available water capacity is high. managing livestock grazing, and reseeding where needed.
The effective rooting depth is 60 inches or more. Surface This soil has poor potential for urban and recreational
runoff is medium, and the erosion hazard is low. development. Slow permeability and high shrink swell
In irrigated areas this soil is suited to all crops com- cause problems in dwelling and road construction. Capa-
monly grown in the area, including corn, sugar beets, bility subclass Ile irrigated, IVe nonirrigated; Clayey
beans, alfalfa, and small grain. An example of a suitable Plains range site.
cropping system is 3 to 4 years of alfalfa followed by 67—Ulm clay loam, 3 to 5 percent slopes. This is a
corn, corn for silage, sugar beets, small grain, or beans. deep, well drained soil on plains at elevations of 5,075 to
Land leveling, ditch lining, and installing pipelines are 5,200 feet. It formed in alluvial and eolian sediments from
needed for proper water applications. shale. Included in mapping are small areas of soils that
All methods of irrigation are suitable, but furrow ir- have shale between depths of 40 and 60 inches. Also in-
rigation is the most common. Barnyard manure and com- eluded are small areas of soils where the surface layer
mercial fertilizer are needed for top yields. and subsoil have been recharged with lime from irriga-
In nonirrigated areas this soil is suited to winter wheat, .lion.
barley, and sorghum. Most of the acreage is planted to Typically the surface of this Ulm soil is brown clay
• winter wheat. The predicted average yield is 28 bushels loam about 5 inches thick. The subsoil is brown and pale
per acre. The soil is summer fallowed in alternate years brown clay about 12 inches thick. The substratum to a
to allow moisture accumulation. Generally precipitation is depth of 60 inches is clay and clay loam.
too low for beneficial use of fertilizer. Permeability is slow. Available water capacity is high.
Stubble mulch fanning, striperopping, and minimum til- The effective rooting depth is 60 inches or more. Surface
lage are needed to control soil blowing and water erosion. runoff is medium, and the erosion hazard is moderate.
Terracing also may be needed to control water erosion. In irrigated areas this soil is suited to the crops com-
The potential native vegetation is dominated by monly grown in the area. Perennial grasses and alfalfa or
western wheatgrass and blue grama. Buffalograss is also close grown crops should be grown at least 50 percent of
present. Potential production ranges from 1,000 pounds the time. Contour ditches and corrugations can be used in
per acre in favorable years to 600 pounds in unfavorable irrigating close grown crops and pasture. Furrows, con-
years. As range condition deteriorates, a blue grama-buf- tour furrows, and cross slope.furrows are suitable for row
falograss sod forms. Undesirable weeds and annuals in- crops. Sprinkler irrigation is also desirable. Keeping til-
vade the site as range condition becomes poorer. lage to a minimum and utilizing crop residue help to con-
Management of vegetation on this soil should be based trol erosion. Maintaining fertility is important. Crops
on taking half and leaving half of the total annual produc- respond to applications of phosphorus and nitrogen.
tion. Range pitting can reduce runoff. Seeding is desirable In nonirrigated areas this soil is suited to winter wheat,
if the range is in poor condition. Western wheatgrass, barley, and sorghum. Most of the acreage is planted to
blue grama, sideoats grama, buffalograss, pubescent winter wheat. The predicted average yield is 28 bushels
wheatgrass, and crested wheatgrass are suitable for seed- per acre. The soil is summer fallowed in alternate years
50 SOIL SURVEY
sugar beets, small grain, or beans. Few conservation prac- The potential native vegetation is dominated by blue
tices are needed to maintain top yields. grama. Several mid grasses, such as western wheatgrass
All methods of irrigation are suitable, but furrow ir- and needleandthread, are also present. Potential produc-
rigation is the most common. Barnyard manure and corn- tion ranges from 1,600 pounds per acre in favorable years
mercial fertilizer are needed for top yields. to 1,000 pounds in unfavorable years. As range condition
Windbreaks and environmental plantings generally are deteriorates, the mid grasses decrease; blue grama, but'-
well suited to this soil. Summer fallow a year before falograss, snakeweed, yucca, and fringed sage increase;
planting and continued cultivation for weed control are and forage production drops. Undesirable weeds and an-
needed to insure establishment and survival of plantings. nuals invade the site as range condition becomes poorer.
Trees that are best suited and have good survival are Management of vegetation on this soil should be based
Rocky Mountain juniper, eastern redcedar, ponderosa on taking half and leaving half of the total annual produc-
pine, Siberian elm, Russian-olive, and hackberry. The tion. Seeding is desirable if the range is in poor condition.
shrubs best suited are skunkbush sumac, lilac, Siberian Sideoats grama, little bluestem, western wheatgrass, blue
peashrub,and American plum. grama, pubescent wheatgrass, and crested wheatgrass are
Openland wildlife, such as pheasant, mourning dove, suitable for seeding. The grass selected should meet the
and cottontail, are best suited to this soil. Wildlife habitat seasonal requirements of livestock. It can be seeded into
development, including tree and shrub plantings and a clean, firm sorghum stubble, or it can be drilled into a
grass plantings to serve as nesting areas, should be sue- firm prepared seedbed. Seeding early in spring has
cessful without irrigation in most years. Under irrigation, proven most successful.
good wildlife habitat can be established, benefiting many Windbreaks and environmental plantings are generally
kinds of openland wildlife. well suited to this soil. Summer fallow a year before
This soil has good potential for urban and recreational planting and continued cultivation for weed control are
development. The chief limiting soil features for urban needed to insure establishment and survival of plantings.
development are the shrink-swell potential of the subsoil Trees that are best suited and have good survival are
as it wets and dries and the limited capacity of the soil to Rocky Mountain juniper, eastern redcedar, ponderosa
support a load. Lawns, shrubs, and trees grow well. Capa- pine, Siberian elm, Russian-olive, and hackberry. The
bility class I irrigated. shrubs best suited are skunkbush sumac, lilac, Siberian
•
79—Weld loam, 1 to 3 percent slopes. This is a deep, peashrub, and American plum.
well drained soil on smooth plains at elevations of 4,850 to Openland wildlife, such as pheasant, mourning dove,
5,000 feet. It formed in eolian deposits. Included in and cottontail, are best suited to this soil. Wildlife habitat
mapping are small areas of soils that have a subsoil of development, including tree and shrub plantings and
loam and light clay loam. Also included are some leveled grass plantings to serve as nesting areas, should be suc-
areas. cessful without irrigation during most years. Under ir-
Typically the surface layer of this Weld soil is brown rigation, good wildlife habitat can be established, benefit-
loam about 8 inches thick. The subsoil is brown and pale ing many kinds of openland wildlife.
brown heavy clay loam and light clay about 20 inches This soil has good potential for urban and recreational
thick.The substratum to a depth of 60 inches is silt loam. development. The chief limiting soil features for urban
Permeability is slow. Available water capacity is high. development are the shrink-swell potential of the subsoil
The effective rooting depth is 60 inches or more. Surface as it wets and dries and the limited capacity of the soil to
runoff is slow,and the erosion hazard is low. support a load. Lawns,shrubs,and trees grow well. Capa-
In irrigated areas this soil is suited to all crops corn- bility subclass Ile irrigated, IIIc nonirrigated; Loamy
monly grown in the area, including corn, sugar beets (fig. Plains range site.
8), beans, alfalfa, small grain,and onions. An example of a 80—Weld loam, 3 to 5 percent slopes. This is a deep,
suitable cropping system is 3 to 4 years of alfalfa fol- well drained soil on plains at elevations of 4,850 to 5,000
lowed by corn, corn for silage, sugar beets, small grain, or feet. It formed in eolian deposits. Included in mapping are
beans. Land leveling, ditch lining, and installing pipelines small areas of soils that have a subsoil of loam and light
are needed for proper water applications. clay loam.
All methods of irrigation are suitable, but furrow ir- Typically the surface layer is brown loam about 8
rigation is the most common. Barnyard manure and com- inches thick. The subsoil is brown and pale brown heavy
mercial fertilizer are needed for top yields. clay loam and light clay about 18 inches thick. The sub-
This soil is well suited to winter wheat, barley, and stratum to a depth of 60 inches is silt loam.
sorghum if it is summer fallowed in alternate years. Permeability is slow. Available water capacity is high.
Winter wheat is the principal crop.The predicted average The effective rooting depth is 60 inches or more. Surface
yield is 33 bushels per acre. If the crop is winterkilled, runoff is medium,and the erosion hazard is moderate.
spring wheat can be seeded. Generally precipitation is too In irrigated areas this soil is suited to most of the crops
low for beneficial use of fertilizer. commonly grown in the area, such as corn, alfalfa, wheat,
Stubble mulch farming, striperopping, and minimum til- and barley. Sugar beets are often grown. The soil is
lage are needed to control soil blowing and water erosion. suited to irrigated pasture. Ditch lining and installing
Terracing also may be needed to control water erosion. pipelines are needed for proper water application.
52 SOIL SURVEY
the limited capacity of this soil to support a load. Capa- Management of vegetation on this soil should be based
bility class I irrigated. on taking half and leaving half of the total annual produc-
82—Wiley-Colby complex, 1 to 3 percent slopes. This tion. Seeding is desirable if the range is in poor condition.
nearly level map unit is on smooth plains in the western Sideoats grama, little bluestem, western wheatgrass, blue
part of the survey area at elevations of 4,850 to 5,000 grama, pubescent wheatgrass, and crested wheatgrass are
feet. The Wiley soil makes up about 60 percent of the suitable for seeding. The grass selected should meet the
unit, and the Colby soil about 30 percent. About 10 per- seasonal requirements of livestock. It can be seeded into
cent is Heldt silty clay and Weld loam. a clean, firm sorghum stubble or it can he drilled into a
The Wiley soil is deep and well drained. It formed in firm prepared seedbed. Seeding early in spring has
calcareous eolian deposits. Typically the surface layer is proven most successful.
pale brown silt loam about 11 inches thick. The subsoil is Windbreaks and environmental plantings are generally
pale brown silty clay loam about 23 inches thick.The sub- well suited to these soils. Cultivation to control competing
stratum to a depth of 60 inches is very pale brown silty vegetation should be continued for as many years as
clay loam. possible following planting.Trees that are best suited and
Permeability is moderately slow. Available water have good survival are Rocky Mountain juniper, eastern
capacity is high. The effective rooting depth is 60 inches redcedar, ponderosa pine, Siberian elm, Russian-olive, and
or more. Surface runoff is medium, and the erosion hackberry. The shrubs best suited are skunkbush sumac,
hazard is moderate. lilac,Siberian peashrub,and American plum.
The Colby soil also is deep and well drained and formed Openland wildlife, such as pheasant, mourning dove,
in calcareous eolian deposits. Typically the surface layer and cottontail are best suited to these soils. Wildlife
is pale brown loam about 7 inches thick. The underlying habitat development, including tree and shrub plantings
material is very pale brown silt loam to a depth of 60 and grass plantings to serve as nesting areas, should be
inches. successful without irrigation during most years. Under ir-
Permeability is moderate. Available water capacity is rigation, good wildlife habitat can be established, benefit-
high. The effective rooting depth is 60 inches or more. ing many kinds of openland wildlife.
Surface runoff is medium, and the erosion hazard is The Wiley soil has only fair potential for urban and
moderate. recreational development. Slow permeability, moderate
This map unit is used for irrigated and nonirrigated shrink-swell potential, and limited bearing capacity cause
cropland and for rangeland, wildlife habitat, and urban problems in dwelling and road construction. The Colby
development. soil has good potential for urban and recreational develop-
In irrigated areas these soils are suited to all crops ment. Road design can be modified to compensate for the
commonly grown in the area, including corn, sugar beets, limited capacity of this soil to support a load. Capability
beans, alfalfa, small grain, and onions. An example of a subclass Ile irrigated, IVe nonirrigated; Loamy Plains
suitable cropping system is 3 to 4 years of alfalfa fol- range site.
lowed by corn, corn for silage, sugar beets, small grain, or 83—Wiley-Colby complex, 3 to 5 percent slopes. This
beans. Land leveling, ditch lining, and installing pipelines gently sloping map unit is on plains at elevations of 4,850
may be needed for proper water applications. to 5,000 feet. The Wiley soil makes up about 60 percent of
All methods of irrigation are suitable, but furrow ir- the unit, and the Colby soil about 30 percent. About 10
rigation is the most common. Barnyard manure and corn- percent is Heldt silty clay and Weld loam.
mercial fertilizer are needed for top yields. The Wiley soil is deep and well drained. It formed in
In nonirrigated areas these soils are suited to winter calcareous eolian deposits. Typically the surface layer is
wheat, barley, and sorghum. Most of the acreage is pale brown silt loam about 11 inches thick. The subsoil is
planted to winter wheat. The predicted average yield is pale brown silty clay loam about 23 inches thick. The sub-
28 bushels per acre. The soil is summer fallowed in al- stratum to a depth of 60 inches is very pale brown silty
ternate years to allow moisture accumulation. Generally clay loam.
precipitation is too low for beneficial use of fertilizer. Permeability is moderately slow. Available water
Stubble mulch farming, striperopping, and minimum til- capacity is high. The effective rooting depth is 60 inches
lage are needed to control soil blowing and water erosion. or more. Surface runoff is medium to rapid, and the ero-
Terracing also may be needed to control water erosion. sion hazard is moderate.
The potential native vegetation is dominated by blue The Colby soil also is deep and well drained and formed
grama. Several mid grasses such as western wheatgrass in calcareous eolian deposits. Typically the surface layer
and needleandthread are also present. Potential produc- is pale brown loam about 7 inches thick. The underlying
tion ranges from 1,600 pounds per acre in favorable years material is very pale brown silt loam to a depth of 60
to 1,000 pounds in unfavorable years. As range condition inches.
deteriorates, the mid grasses decrease; blue grama, buf- Permeability is moderate. Available water capacity is
falograss, snakeweed, yucca and fringed sage increase; high. The effective rooting depth is 60 inches or more.
and forage production drops. Undesirable weeds and an- Surface runoff is medium to rapid, and the erosion hazard
nuals invade the site as range condition becomes poorer. is moderate.
WELD COUNTY, COLORADO, SOUTHERN PART 53
This unit is used for irrigated and nonirrigated The Wiley soil has only fair potential for urban and
cropland and for rangeland, wildlife habitat, and urban recreational development. Slow permeability, moderate
development. shrink-swell potential, and limited bearing capacity cause
In irrigated areas these soils are suited to the crops problems in dwelling and road construction. The Colby
commonly grown in the area. Perennial grasses and alfal- soil has good potential for urban and recreational develop-
fa or close grown crops should be grown at least 50 per- ments. Road design can be modified to compensate for
cent of the time. Contour ditches and corrugations can be the limited capacity of this soil to support a load. Capa-
used in irrigating close grown crops and pasture. Fur- bility subclass IIIe irrigated, IVe nonirrigated; Loamy
rows, contour furrows, and cross slope furrows are suita- Plains range site.
ble for row crops. Sprinkler irrigation is also desirable.
Keeping tillage to a minimum and utilizing crop residue Use and management of the soils
help to control erosion. Maintaining fertility is important.
Crops respond to applications of phosphorus and nitrogen. The soil survey is a detailed inventory and evaluation
In nonirrigated areas these soils are suited to winter of the most basic resource of the survey area—the soil. It
wheat, barley, and sorghum. Most of the acreage is is useful in adjusting land use, including urbanization, to
planted to winter wheat. The predicted average yield is the limitations and potentials of natural resources and the
28 bushels per acre. The soil is summer fallowed in al- environment. Also, it can help avoid soil-related failures
ternate years to allow moisture accumulation. Generally in uses of the land.
precipitation is too low for beneficial use of fertilizer. While a soil survey is in progress, soil scientists, con-
Stubble mulch farming, striperopping, and minimum til- servationists, engineers, and others keep extensive notes
lage are needed to control soil blowing and water erosion. about the nature of the soils and about unique aspects of
Terracing also may be needed to control water erosion. behavior of the soils. These notes include data on erosion,
The potential native vegetation is dominated by blue drought damage to specific crops, yield estimates, flood-
grama. Several mid grasses, such as western wheatgrass ing, the functioning of septic tank disposal systems, and
and needleandthread, are also present. Potential produc- other factors affecting the productivity, potential, and
tion ranges from 1,600 pounds per acre in favorable years limitations of the soils under various uses and manage-
to 1,000 pounds in unfavorable years. As range condition ment. In this way, field experience and measured data on
deteriorates, the mid grasses decrease; blue grama, buf- soil properties and performance are used as a basis for
falograss, snakeweed, yucca, and fringed sage increase; predicting soil behavior.
and forage production drops. Undesirable weeds and an- Information in this section is useful in planning use and
nuals invade the site as range condition becomes poorer. management of soils for crops, pasture, and rangeland, as
Management of vegetation on these soils should be sites for buildings, highways and other transportation
based on taking half and leaving half of the total annual systems, sanitary facilities, and parks and other recrea-
production. Seeding is desirable if the range is in poor tion facilities, and for wildlife habitat. From the data
condition. Sideoats grama, little bluestem, western wheat- presented, the potential of each soil for specified land
grass, blue grama, pubescent wheatgrass, and crested uses can be determined, soil limitations to these land uses
wheatgrass are suitable for seeding. The grass selected can be identified, and costly failures in houses and other
should meet the seasonal requirements of livestock. It can structures, caused by unfavorable soil properties, can be
be seeded into a clean, firm sorghum stubble, or it can be avoided. A site where soil properties are favorable can be
e
drilled into a firm prepared seedbed. Seeding early in selected, practices that will overcome the soil limita-
tions can b be planned.
spring has proven most successful. Planners and others using the soil survey can evaluate
Windbreaks and environmental plantings of trees and the impact of specific land uses on the overall productivi-
shrubs commonly grown in the area are generally well ty of the survey area or other broad planning area and on
suited to these soils. Cultivation to control competing the environment. Productivity and the environment are
vegetation should be continued for as many years as closely related to the nature of the soil. Plans should
possible following plantings. Trees that are best suited maintain or create a land-use pattern in harmony with the
and have good survival are Rocky Mountain juniper, east- natural soil.
ern redcedar, ponderosa pine, Siberian elm, Russian-olive, Contractors can find information that is useful in locat-
and hackberry. The shrubs best suited are skunkbush ing sources of sand and gravel, roadfill, and topsoil. Other
sumac, lilac, Siberian peashrub, and American plum. information indicates the presence of bedrock, wetness,or
Openland wildlife, such as pheasant, mourning dove, very firm soil horizons that cause difficulty in excavation.
and cottontail, are best suited to these soils. Wildlife Health officials, highway officials, engineers, and many
habitat development, including tree and shrub plantings other specialists also can find useful information in this
and grass plantings to serve as nesting areas, should be soil survey. The safe disposal of wastes, for example, is
successful without irrigation during most years. Under ir- closely related to properties of the soil. Pavements, side-
rigation, good wildlife habitat can be established, benefit- walks, campsites, playgrounds, lawns, and trees and
ing many kinds of openland wildlife. shrubs are influenced by the nature of the soil.
WELD COUNTY, COLORADO, SOUTHERN PART 55
seedbed just before planting, which eliminates the hazard favorable; control of weeds, plant diseases, and harmful
of soil blowing in winter and early in spring. insects; favorable soil reaction and optimum levels of
The heavier textured Colombo, Heldt, Nunn, Renohill, nitrogen, phosphorus, potassium, and trace elements for
Ulm, and Wiley soils often benefit from fall plowing. each crop; effective use of crop residues, barnyard
They are generally not subject to blowing if the tillage manure, and green-manure crops; harvesting crops with
consists only of plowing and disking. They are subject to the smallest possible loss; and timeliness of all fieldwork.
more compaction, however, and are often cloddy after For yields of irrigated crops, it is assumed that the ir-
plowing. The action of freezing and thawing helps to rigation system is adapted to the soils and to the crops
break up the clods, and a good seedbed can be prepared grown; that good quality irrigation water is uniformly ap-
in spring. Seedbed preparation can be delayed because plied in proper amounts as needed; and that tillage is
the soils are often too wet for plowing early in spring. kept to a minimum.
Field crops best suited to the soils and climate of the The estimated yields reflect the productive capacity of
survey area are mainly those that are commonly grown. the soils for each of the principal crops. Yields are likely
Corn, both for silage and grain, sugar beets, dry beans, to increase as new production technology is developed.
and potatoes are the main cultivated crops; alfalfa is the The productivity of a given soil compared with that of
main hay crop. Permanent pasture is generally a mixture other soils, however, is not likely to change.
of perennial grasses and legumes. Crops other than those shown in table 5 are grown in
Special crops grown commercially are vegetables and the survey area (fig. 10), but estimated yields are not in-
nursery stock. Large acreages of onions, cucumbers for eluded because the acreage of these crops is small. The
pickles, and carrots are grown in the Greeley area. Some local offices of the Soil Conservation Service and the
melons are grown in the Kersey area. There are a Cooperative Extension Service can provide information
number of truck farms between Fort Lupton and about the management concerns and productivity of the
soils for these crops.
Brighton where strawberries, asparagus, cabbage, to-
matoes, celery, peppers, sweet corn, and other vegetables Capability classes and subclasses
are grown for the Denver market.
Current information and suggestions for growing spe- Capability classes and subclasses show, in a general
cial crops can be obtained from local offices of the way, the suitability of soils for most kinds of field crops.
Colorado State University Extension Service and the Soil The soils are classed according to their limitations when
Conservation Service. they are used for field crops, the risk of damage when
they are used, and the way they respond to treatment.
Yields per acre The grouping does not take into account major and
generally expensive landforming that would change slope,
The average yields per acre that can be expected of the
principal crops under a high level of management are depth, or other characteristics of the soils; does not take
into consideration possible but unlikely major reclamation
shown in table 5. In any given year, yields may be higher projects; and does not apply to rice, cranberries, horticul-
or lower than those indicated in the table because of tural crops, or other crops that require special manage-
variations in rainfall and other climatic factors. Absence ment. Capability classification is not a substitute for in-
of an estimated yield indicates that the crop is not suited terpretations designed to show suitability and limitations
to or not commonly grown on the soil or that a given crop of groups of soils for rangeland or for engineering pur-
is not commonly irrigated. poses.
The estimated yields were based mainly on the ex- In the capability system,all kinds of soil are grouped at
perience and records of farmers, conservationists, and ex- two levels: capability class and subclass. These levels are
tension agents. Results of field trials and demonstrations defined in the following paragraphs. A survey area may
and available yield data from nearby counties were also not have soils of all classes.
considered. Capability classes, the broadest groups, are designated
The yields were estimated assuming that the latest soil by Roman numerals I through VIII. The numerals in-
and crop management practices were used. Hay and dicate progressively greater limitations and narrower cho-
pasture yields were estimated for the most productive ices for practical use.The classes are defined as follows:
varieties of grasses and legumes suited to the climate and Class I soils have few limitations that restrict their use.
the soil. A few farmers may be obtaining average yields Class II soils have moderate limitations that reduce the
higher than those shown in table 5. choice of plants or that require moderate conservation
The management needed to achieve the indicated yields practices.
of the various crops depends on the kind of soil and the Class III soils have severe limitations that reduce the
crop. Such management provides drainage, erosion con- choice of plants, or that require special conservation prac-
trol, and protection from flooding; the proper planting tices, or both.
and seeding rates; suitable high-yielding crop varieties; Class IV soils have very severe limitations that reduce
appropriate tillage practices, including time of tillage and the choice of plants, or that require very careful manage-
seedbed preparation and tilling when soil moisture is ment, or both.
74 SOIL SURVEY
Thedalund series Clca-19 to 34 inches; very pale brown (10YR 7/3) clay, pale brown
(10YR 6/3) moist; weak coarse subangular blocky structure; ex-
tremely hard, very firm;some visible lime occuring in medium soft
The T series consists of moderately deep, well masses;calcareous;moderately alkaline;gradual smooth boundary.
soils that
soils that formed in residuum from soft calcare C2ca-34 to 60 inches; very pale brown (10YR 7/3) clay loam, pale
ous shale. Thedalund soils are on plains. Slopes are 1 to 9 brown(10YR 6/3) moist; weak coarse subangular blocky structure;
percent. very hard,firm; some visible lime occuring in medium soft masses;
Thedalund soils are similar to Kim, Nelson, Otero, Shin- calcareous;moderately alkaline.
gle, and Tassel soils and are near the Olney and Terry Thickness of the solum ranges from 15 to 36 inches. Rock fragments
soils. Kim, Otero, and Olney soils are deep. Nelson and make up 0 to 5 percent of the solum.
Tassel soils are less than 18 percent clay in the C horizon. The A horizon has hue of 10YR or 2.5Y,value of 5 or 6 dry and 4 or 5
Terry soils have a B2t horizon that is less than 18 percent moist,and chroma of 2 or 3.The B2t horizon is commonly clay that is 40
clay. Shingle soils have shale between 10 and 20 inches. to 50 percent clay.
Typical pedon of Thedalund loam, 3 to 9 percent slopes,
2,050 feet north and 1,800 feet east of southwest corner Valent series -
sec.29,T.7 N.,R. 65 W. The Valent series consists of deep, excessively drained
Ap-0 to 8 inches; brown (10YR 5/3) loam, dark brown (10YR 4/3) soils that formed in eolian deposits. Valent soils are on
moist; moderate fine granular structure; slightly hard, friable; 5 plains. Slopes are 0 to 9 percent.
percent shale chips; calcareous;moderately alkaline;abrupt smooth
boundary. Valent soils are near the Loup, Boel, Osgood, and Vona
Clca-8 to 12 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3) soils. Loup and Boel soils are poorly drained. Osgood and
moist; weak fine granular structure; slightly hard, friable; some Vona soils have a B horizon.
visible lime in medium soft masses;calcareous;moderately alkaline; Typical pedon of Valent sand, 0 to 3 percent slopes,
clear smooth boundary. 2,220 feet north and 132 feet west of southeast corner
C2ca-12 to 25 inches;very pale brown(10YR 7/4)loam stratified with
thin lenses of shale,light yellowish brown (10YR 6/4) moist; mas- sec.8,T.4 N., R.62 W.
sive; slightly hard, friable; some visible lime occuring in medium
soft masses;calcareous;moderately alkaline;abrupt smooth bounds- Al-0 to 8 inches; brown (10YR 5/3) sand,dark grayish brown(10YR
IT. 4/2)moist;single grained;loose;neutral;clear smooth boundary.
C3r-25 inches;soft calcareous shale. Cl-8 to 60 inches;brown(10YR 5/3)sand,dark grayish brown(10YR
4/2)moist;single grained;loose;neutral.
Typically these soils have free carbonates at the surface. Depth to
shale ranges from 20 to 40 inches. Content of rock fragments ranges Coarse fragments make up 0 to 10 percent of the solum and are
from 0 to 15 percent mainly scattered gravel. Depth to free carbonates is more than 40
The A horizon has hue of 10YR or 2.5Y,value of 5 or 6 dry and 4 or 5 inches.
moist,and chrome of 2 or 3.The C horizon has hue of 10YR or 2.5Y.It The A horizon has hue of 10YR and 2.5Y,value of 5 or 6 dry and 3 to
is loam or clay loam that is 18 to 35 percent clay. 5 moist,and chroma of 2 or 3.
Ulm series Vona series
The Ulm series consists of deep, well drained soils that The Vona series consists of deep, well drained to
formed in calcareous alluvial and eolian sediments from somewhat excessively drained soils that formed in eolian
shale. Ulm soils are on plains. Slopes are 0 to 5 percent. or alluvial deposits. Vona soils are on plains and high ter-
Ulm soils are similar to the Fort Collins, Renohill, and races. Slopes are 0 to 9 percent.
Wiley soils and are near the Heldt and Nunn soils. Fort Vona soils are similar to the Olney and Terry soils and
Collins and Wiley soils are less than 35 percent clay in are near the Ascalon, Bresser, Julesburg, Osgood, Otero,
the B2t horizon. Renohill soils have shale between 20 and and Valent soils. Olney, Ascalon, and Dresser soils are
40 inches. Heldt soils lack a B2t horizon. Nunn soils have more than 18 percent clay in the B2t horizon. Terry soils
a dark colored surface layer. have sandstone between 20 and 40 inches.Julesburg soils
Typical pedon of Ulm clay loam, 0 to 3 percent slopes, have a dark colored surface layer. Osgood soils have an A
1,370 feet north and 240 feet west of southeast corner •
horizon that is coarser than loamy fine sand and is more
sec. 33,T. 1 N., R.68 W. than 20 inches thick. Otero and Valent soils lack a B
Ap-0 to 5 inches; brown (10YR 5/3) clay loam, dark grayish brown horizon.
(10YR 4/2) moist; moderate fine granular structure; slightly hard, Typical pedon of Vona loamy sand, 0 to 3 percent _
firm;calcareous;mildly alkaline;abrupt smooth boundary. 180 feet north and 1,400 feet east of southwest
B2t-5 to 13 inches;brown(10YR 5/3)clay,dark grayish brown(10YR slopes,
4/2) moist; weak coarse angular blocky structure parting to corner sec.25,T.5 N., R. 61 W.
moderate medium angular blocky; extremely hard,extremely firm; Al-0 to 6 inches;grayish brown (10YR 5/2) loamy sand,dark grayish
mildly mmoa mine clear thick clay films on faces of peds; calcareous; brown (10YR 4/2) moist; weak fine granular structure; soft, very
alkaline;clear smooth boundary. friable;neutral;clear smooth boundary.
Baca—is to 19 inches; pale brown 6/3) clay, brown (10YR 5/3)
moist; weak coarse angular blocky structure;structct ure; extremely hard, ex- A3-6 Co 12 inches; grayish brown (lOYR 5/2) fine sandy loam, dark
tremely firm;few thin clay films on faces of some peds;some visi- grayish brown (10YR 4/2) moist; weak coarse subangular blocky
ble lime in fine seams; calcareous; moderately alkaline; gradual structure;slightly hard,very friable; neutral;clear smooth bounds-
smooth boundary. ry'
WELD COUNTY, COLORADO, SOUTHERN PART 75
B21t-12 to 16 inches;brown(10YR 5/3)fine sandy loam,brown(10YR Wiley series
4/3) moist; moderate medium prismatic structure parting to
moderate medium subangular blocky; hard, friable; few thin clay The Wiley series consists of deep, well drained soils
films on faces of peds;neutral;clear smooth boundary. that formed in calcareous eolian deposits. Wiley soils are
B22t-16 to 22 inches; yellowish brown (10YR 5/4) fine sandy loam,
brown (10YR 4/3) moist; moderate medium prismatic structure on plains. Slopes are 0 to 5 percent.
parting to weak medium subangular blocky; hard,friable; few thin Wiley soils are similar to the Renohill and Ulm soils
clay films on faces of peds;neutral;gradual smooth boundary. and are near the Colby, Heldt, and Weld soils. Renohil7
B3-22 to 28 inches; light yellowish brown(10YR 6/4)fine sandy loam, soils have shale between 20 and 40 inches. Ulm, Hekit,
yellowish brown (10YR 5/4) moist; weak coarse subanglar blocky and Weld soils are more than 35 percent clay in the B2
structure; slightly hard, very friable; calcareous; mildly alkaline; horizon. Colby soils lack a B horizon.
clear smooth boundary. Typical
Cca-28 to 60 inches;light yellowish brown(10YR 6/4)sandy loam,yel-
lowish brown(10YR 5/4)moist;massive;slightly hard,very friable; Colby complex, 1 to 3 percent slopes, in the northeast
some visible lime in fine filaments or threads;calcareous;moderate- quarter sec. 34,T.3 N., R. 68 W.
ly alkaline.
Ap-0 to 11 inches;pale brown(10YR 6/3)silt loan,dark grayish brown
Thickness of the solum ranges from 18 to 37 inches.Coarse fragments (10YR 4/2) moist; weak fine granular structure; very hard, friable;
make up 0 to 10 percent of the solum.Depth to free carbonates ranges calcareous;mildly alkaline;clear smooth boundary.
from 12 to 24 inches. B2t-11 to 24 inches; pale brown (10YR 6/3) silty clay loam, brown
The A horizon has value of 5 or 6 dry and 3 to 5 moist and chroma of (IOYR 5/3) moist; weak medium prismatic structure parting to
2 or 3.It is loamy sand or sandy loam.The B2t horizon is commonly fine moderate medium subangular blocky; very hard,firm;few thin clay
sandy loam that is 10 to 18 percent clay. The C horizon ranges from films on faces of peds; calcareous; moderately alkaline; gradual
coarse loamy sand to sandy loam smooth boundary.
B3ca-24 to 34 inches; pale brown (10YR 6/3) silty clay loan, brown
Weld series (10YR 5/3) moist; weak medium prismatic structure parting to
moderate medium subangular blocky; very hard,firm;some visible
lime in fine filaments and seams; calcareous; moderately alkaline;
The Weld series consists of deep, well drained soils that gradual smooth boundary.
formed in calcareous eolian deposits. Weld soils are on Cca-34 to 60 inches;very pale brown(10YR 7/3)silty clay loam,brown
(10YR 5/3) moist; massive; very hard, friable; some visible lime in
smooth plains. Slopes are 0 to 5 percent.
fine soft masses;calcareous;moderately alkaline.
Weld soils are near the Adena, Colby, Nunn, and Wiley
soils. Adena soils have a light colored surface layer and Thickness of the solum ranges from 16 to 40 inches.Typically these
solum less than 15 inches thick. Colby soils lack a B soils have free carbonates at the surface.
The A horizon has hue of 10YR or 25Y,value of 5 to 7 dry and 3 to 5
horizon. Wiley soils have a light colored surface layer and moist,and chroma o£2 or 3.The 82t horizon is commonly silty clay loam
less clay in the B2t horizon. Nunn soils lack an abrupt that is 28 to 35 percent clay.The C horizon is commonly silty clay loam
textural boundary between the A and B horizon. or silt loam.
Typical pedon of Weld loam, 1 to 3 percent slopes, 2,470
feet south and 200 feet west of northeast corner sec. 35, References
T. I N., R. 61 W.
Ap-0 to 8 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) (1) American Association of State Highway(and Transportation)Offi-
cials. 1970. Standard specifications for highway materials and
moist; moderate medium granular structure; hard, friable; neutral; methods of sampling and testing.Ed.10,2 voL,illus.
abrupt smooth boundary. - (2) American Society for Testing and Materials.1974.Methods for clas-
B2lt-8 to 12 inches; brown (10YR 5/3) light clay, brown (10YR 4/3) sification of soils for engineering purposes.ASTM Stand.D 2487-
moist;strong fine prismatic structure parting to strong fine angular 69. In 1974 Annual Book of ASTM Standards, Part 19, 464 pp.,
blocky; very hard, finn; many moderately thick clay films on faces illus.
of peds;neutral;clear smooth boundary. (3) Colorado Department of Agriculture. 1975. Colorado agricultural
B22t-12 to 15 inches; pale brown (10YR 6/3) heavy clay loam, brown statistics, 1974 Preliminary,1973 Final Bull,1-75.
(10YR 4/3)moist; strong fine prismatic structure parting to strong (4) United States Department of Agriculture. 1951.Soil survey manual.
fine angular blocky; very hard, firm; many moderately thick clay U.S.Dep.Agric.Handb. 18,503 pp,illus.(Supplements replacing
films on faces of peds;neutral;clear smooth boundary. pp.173-188 issued May 1962)
Baca-15 to 28 inches; very pale brown (10YR 7/3) loam pale brown (5) United States Department of Agriculture. 1975. Soil Taxonomy. A
(10YR 6/3)moist; moderate medium prismatic structure parting to basic system of soil classification for making soil surveys. Soil
moderate medium subangular blocky; hard, friable; few thin clay Conserv.Service,U.S.Dep.Agric,Handb.436,754 pp,illus.
films on faces of some peds;some visible lime occuring in fine soft
masses;calcareous;moderately alkaline;clear smooth boundary. Glossary
Cca-28 to 60 inches;very pale brown(10YR 7/3)silt loam,pale brown
(10YR 6/3)moist; massive; slightly hard, friable; some visible lime
in fine filaments or threads;calcareous;moderately alkaline. ABC soil.A soil having an A,a B,and a C horizon.
AC soil. A soil having only an A and a C horizon. Commonly such soil
Thickness of the solum ranges from 20 to 39 inches.Depth to free car- formed in recent alluvium or on steep rocky slopes.
bonates ranges from 10 to 20 inches. Aeration,soil.The exchange of air in soil with air from the atmosphere.
The A horizon has value of 4 or 5 dry and 2 or 3 moist and chroma of The air in a well aerated soil is similar to that in the atmosphere;
2 or 3.The B2t horizon is commonly light clay or heavy clay loam that is the air in a poorly aerated soil is considerably higher in carbon diox-
35 to 45 percent clay.The C horizon is commonly silt loam or loam. ide and lower in oxygen.
WELD COUNTY, COLORADO, SOUTHERN PART 103
TABLE 6.--BUILDING SITE DEVELOPMENT--Continued
Soil name and Shallow Dwellings Dwellings Small Local roads
map symbol excavations without with commercial and streets
basements basements buildings
66, 67 Moderate: Severe: Severe: Severe: Severe:
Ulm too clayey. shrink-swell. shrink-swell. shrink-swell. low strength,
shrink-swell.
68* Severe: Moderate: Moderate: Moderate: Moderate:
Ustic small stones, slope. slope. slope. slope.
Torriorthents cutbanks cave.
69 Severe: Slight Slight Slight Slight.
Valent cutbanks cave. /'
70 Severer Slight Slight Moderate: Slight.
Valent cutbanks cave. slope.
71*:
Valent Severe: Slight Slight Moderate: Slight.
cutbanks cave. slope.
Loup Severe: Severe: Severe: Severe: Severe:
wetness, wetness, wetness, wetness, wetness.
cutbanks cave. floods. floods. floods.
72 Slight Slight Slight Slight Moderate:
Vona low strength.
73, 74 Slight Slight Slight Moderate: Moderate:
Vona slope. low strength.
75, 76 Slight Slight Slight Slight Moderate:
Vona low strength.
•
77 Slight Slight Slight Moderate: Moderate:
Vona slope. low strength.
78, 79 Slight Moderate: Moderate: Moderate: Moderate:
Weld low strength, low strength, low strength, low strength,
shrink-swell. shrink-swell. shrink-swell. shrink-swell,
frost action.
80 Slight Moderate: Moderate: Moderate: Moderate:
Weld low strength, low strength, low strength, low strength,
shrink-swell. -shrink-swell. slope, shrink-swell,
shrink-swell. frost action.
81*, 82*: ..
Wiley Slight Moderate: Moderate: Moderate: Moderate:
low strength, low strength, low strength, low strength,
shrink-swell. shrink-swell. shrink-swell. shrink-swell.
Colby Slight Slight Slight Slight Moderate:
low strength.
83*:
Wiley Slight Moderate: Moderate: Moderate: Moderate:
low strength, low strength, 1 low strength, low strength,
shrink-swell. shrink-swell. ; slope, shrink-swell.
shrink-swell.
Colby Slight Slight Slight ',Moderate: Moderate:
; slope. low strength.
* See map unit description for the composition and behavior of the map unit.
106 SOIL SURVEY
TABLE 7.--SANITARY FACILITIES--Continued
Soil name and ; Septic tank Sewage lagoon Trench Area Daily cover
map symbol absorption areas sanitary sanitary for landfill
fields landfill landfill
43 ',Severe: Moderate: Slight Slight Fair:
Nunn peres slowly. excess humus. too clayey.
44, 45, 46, 47, 48--:Slight Severe: Slight Slight Good.
Olney seepage.
49 Slight Severe: - Severe: Severe: Fair:
Osgood seepage. seepage. seepage. too sandy.
50, 51, 52 Slight Severe: Slight Slight Good.
Otero seepage.
53 Slight Severe: Slight Slight Good.
Otero slope,
seepage.
54 Slight Severe: Severe: Severe: Good.
Paoli seepage. seepage. seepage.
55 Slight Severe: Severe: Severe: Good.
Paoli seepage. seepage. seepage.
56, 57 ;Severe: Severe: Severe: Slight Fair:
genohill ; peres slowly, depth to rock. depth to rock. too clayey,
I depth to rock. thin layer.
58, 59 Severe: Severe: Severe: Slight Poor:
Shingle depth to rock. depth to rock. depth to rock. thin layer.
60"
Shingle ;Severe: Severe: Severe: Slight Poor:
depth to rock. depth to rock. depth to rock. thin layer.
Renohill Severe: Severe: Severe: Slight Fair:
peres slowly, depth to rook. depth to rock. • too clayey,
depth to rock. thin layer.
61 Severe: Severe: Severe: Severe: Poor:
Tassel depth to rock. depth to rock, depth to rook, seepage. thin layer,
seepage, seepage. area reclaim.
slope.
62, 63 Severe: Severe: Severe: Slight Fair:
Terry depth to rook. depth to rock, depth to rock. thin layer,
seepage. area reclaim.
64, 65 Severe: Severe: Severe: Slight Fair:
Thedalund depth to rock. depth to rock, depth to rock. thin layer.
66 Severe: Slight Moderate: Slight Poor:
Ulm peres slowly. too clayey. too clayey.
67 Severe: Moderate: Moderate: Slight Poor:
Ulm pares slowly. slope. too clayey. too clayey.
68" Moderate: Severe: Severe: Severe: Poor:
Ustic Torriorthents slope. seepage, seepage, seepage. too sandy,
small stones. too sandy. small stones.
69, 70 Slight Severe: Severe: Severe: Poor:
Valent seepage. too sandy, seepage, too sandy.
seepage.
71":
Valent Slight ;Severe: Severe: Severe: Poor:
I seepage. too sandy, seepage. too sandy.
seepage.
See footnote at end of table.
WELD COUNTY, COLORADO, SOUTHERN PART 107
TABLE 7.--SANITARY FACILITIES--Continued
Soil name and Septic tank Sewage lagoon Trench Area Daily cover
map symbol absorption areas sanitary sanitary for landfill
fields landfill landfill
71*:
Loup Severe: Severe: :Severe: Severe: Poor:
wetness, wetness, wetness, wetness, wetness.
floods. seepage, ; seepage, seepage,
floods. I floods. floods.
72, 73 Slight Severe: ;Slight Slight Good.
Vona seepage.
78 Slight Severe: :Slight Slight Good.
Vona seepage,
slope. .
75, 76, 77 Slight Severe: :Slight Slight :Good.
Vona seepage.
78 Moderate: 'Moderate: ;Slight Slight Good.
Weld percs slowly. seepage.
79, 80 Moderate: Moderate: :Slight Slight Good.
Weld percs slowly. slope,
seepage
81': .
Wiley Moderate: Moderate: ;Slight Slight Fair:
percs slowly. seepage. too. clayey.
Colby Slight Moderate: :Slight Slight Good.
seepage.
82', 83':
Wiley Moderate: Moderate: :Slight Slight Fair:
percs slowly. seepage, too clayey.
slope.
Colby Slight Moderate: Slight Slight :Good.
seepage.
* See map unit description for the composition and behavior of the map unit.
•
114 SOIL SURVEY
TABLE 9.--WATER MANAGEMENT--Continued
Soil name and Pond Embankments, Drainage Irrigation Terraces Grassed
map symbol 1 reservoir dikes, and and waterways
areas levees diversions
63 :Slope, Piping, Slope, Slope, Slope, Slope,
Terry ; depth to rock, thin layer. rooting depth. rooting depth, depth to rock, rooting depth,
seepage. soil blowing. soil blowing. soil blowing.
64 ;Depth to rock, Low strength, Slope, Slope, Depth to rock Rooting depth.
Thedalund I slope. Piping, depth to rock. rooting depth.
thin layer.
65 :Depth to rock, Low strength, Slope, Slope, Depth to rock Slope,
Thedalund I slope. piping, depth to rock. rooting depth. rooting depth.
thin layer.
66 Favorable Low strength, Favorable Peres slowly, Peres slowly--- Erodes easily.
Ulm shrink-swell, erodes easily.
compressible.
67 Slope Low strength, Slope Slope, Peres slowly--- Erodes easily.
Ulm shrink-swell, peres slowly,
compressible. erodes easily.
68a Seepage, Seepage Slope Slope, Too sandy, Droughty,
Ustic slope. droughty. slope. slope.
Torriorthents
6g Seepage, Piping, Slope Slope, Erodes easily, Erodes easily.
Valent slope. seepage. erodes easily, piping.
droughty.
70 Seepage, Piping, Slope Slope, Erodes easily, Slope,
Valent, slope. seepage. erodes easily, piping. erodes easily.
droughty.
71e:
Valent Seepage, Piping, Slope Slope, Erodes easily, Slope,
slope. seepage. erodes easily, piping. erodes easily.
droughty.
Loup Seepage Seepage, Poor outlets, Wetness, Not needed Not needed.
piping. cutbanks cave. seepage.
72, 73 - Seepage, Piping, Slope Slope, Piping, Erodes easily.
Vona slope. erodes easily, fast intake, erodes easily.
seepage. seepage. -
7y Seepage, Piping, Slope Slope, Piping, Slope,
Vona slope. erodes easily, fast intake, erodes easily. erodes easily.
seepage. seepage.
75 Seepage, Piping, 'Favorable East intake, Piping, Erodes easily.
Vona • slope. erodes easily, seepage. erodes easily.
seepage.
76, 77 Seepage, Piping, Slope Slope, Piping, Erodes easily.
Vona slope. erodes easily, fast intake, I erodes easily.
seepage. seepage.
78 Seepage Low strength--- Peres slowly--- Peres slowly, Piping, Peres slowly.
Weld slow intake. peres slowly.
79, 80 Seepage Low strength--- Slope, Slope, Piping, Peres slowly.
Weld pesos slowly. pesos slowly, peres slowly.
slow intake.
813:
Wiley Slope, Piping, Peres slowly--- Favorable I Piping Erodes easily.
seepage. I low strength.
Colby Seepage :Low strength, 'Favorable Favorable :Favorable Favorable.
piping.
See footnote at end of table.
WELD COUNTY, COLORADO, SOUTHERN PART
TABLE 9.--WATER MANAGEMENT--Continued
Soil name and Pond Embankments, Drainage t Irrigation Terraces Grassed
map symbol reservoir dikes, and and waterways
areas levees diversions
82•:
Wiley Slope, Piping, Slope, ;Slope, Piping Erodes easily.
seepage. low strength. peres slowly. ; erodes easily.
Colby Seepage Low strength, Favorable ;Favorable Favorable Slope,
piping. erodes easily.
83•:
Wiley Slope, Piping, Slope, !Slope, Piping Slope,
seepage. low strength. peres slowly. I erodes easily. erodes easily.
Colby Seepage Low strength, Slope ,'Slope, Favorable Slope,
piping. I erodes easily. erodes easily.
• See map unit description for the composition and behavior of the map unit, -
122 SOIL SURVEY
TABLE 11.--WILDLIFE HABITAT POTENTIALS--Continued
Potential for habitat elements -T- Potential as habitat for--
Soil name and Wild --- -- --- ---
map symbol Grain Grasses herbs- Shrubs ; Wetland Shallow Openland Wetland ;Rangeland
and seed and ceous 1 plants water wildlife wildlife ;wildlife
crops** legumes plants ; areas
31, 32 Good Good Fair Fair ;Poor Very poor Good Very poor Fair.
Kim
33, 34 Fair Good Fair Fair ;Poor Very poor Fair Very poor Fair.
Kim
35*:
Loup Poor Fair Good Fair :Good Good Fair Good Fair.
Boel Poor Fair Good Fair ;Good Good Fair Good Fair.
36*
Midway Poor Fair Fair Fair :Very poor Very poor Fair Very poor Fair.
Shingle Poor Fair Fair ;Fair ;Very poor Very poor Fair Very poor Fair.
37, 38 Fair Good Fair ;Fair ;Poor Very poor Fair Very poor Fair.
Nelson
39, 40, 41, 42, 43- Good Good Fair ;Fair 'Poor Very poor Good
Nunn Very poor Fair.
44, 45 :Fair Good Fair Fair' Poor Very poor Fair Very poor Fair.
Olney
46, 47 ;Good Good Fair Fair Poor Very poor Good Very poor Fair.
Olney
48 Fair Good Fair Fair Ver
Olney Y poor Very poor Fair Very poor Fair.
49 Poor Fair Fair Fair Very poor Very poor Fair Very poor Fair.
Osgood
50 Good Good ;Fair Fair Poor Very poor Good Very poor Fair.
51, 52, 53 Fair Good :Fair Fair Very poor.Very poor Fair Very poor Fair.
Otero
54, 55 Good Good Fair Fair Poor Very poor Good Very poor Fair.
Paoli
56, 57 Fair Good Fair Fair Poor Very poor Fair Very poor Fair.
Renohill
58, 59 Poor Poor Fair ;Fair Poor Very poor Poor Very poor Fair.
Shingle
60*:
Shingle Poor Poor Fair ;Fair Poor Very poor Poor Very
poor Fair.
Renohill ;Fair Good ;Fair ;Fair Poor Very poor Fair Very poor Fair.
61 ;Poor Poor Poor ;Poor Very poor Very poor Poor Very poor Poor.
Tassel
62, 63 •
;Fair Good Fair ;Fair Very poor Very poor Fair Very poor Fair.
Terry
64, 65 ;Fair ;Fair Fair :Fair Very poor Very poor Fair Very poor Fair.
Thedalund
66 ;Good ;Good Fair Fair Poor Very poor Good
Ulm Very poor Fair.
67 ;Fair Good ;Fair ;Fair Poor Very poor;Fair Very Y poor Fair.
See footnote at end of table.
WELD COUNTY, COLORADO, SOUTHERN PART 123
TABLE 11.--WILDLIFE HABITAT POTENTIALS--Continued
Potential for habitat elements Potential as habitat for__
Soil name and 1 - 1 Wild
map symbol Grain Grasses 1 herba- Shrubs Wetland Shallowr :0peo;wildli de wildlife :Rangeland
'and seed and ceous plants
areas
crops** legumes plants r-- —T
68* Very poor Very poorlPoor Poor Very poor Very poor Very poor Very poor Poor.
Ustic
Torriorthents
69,
70 Poor Fair :Fair Fair Very poor Very poor Fair Very poor Fair.
Valent t
71'; ,Fair Very poor Very poor Fair Very poor Fair.
Valent Poor Fair Fair
Loup
Poor Fair Good Fair Good Good Fair Good Fair.
72, 73 Fair Good Fair Fair Poor Very poor Fair Very poor Fair.
Vona
74 Poor Good Fair Fair Very poor Very poor Fair Very poor Fair.
Vona
45, 76 Good Good Fair Fair Poor Very poor Good Very poor Fair.
Vona
77 Fair Good Fair Fair Very poor Very poor Fair Very poor Fair.
Vona •
78, 79 Good Good Fair
Poor Poor Very poor Good Very poor Poor.
Weld
BO ,Fair Good Fair Poor Poor Very poor Fair Very poor:Poor.
Weld
81* 82*.
Wiley :Good Good Fair Fair Poor Very poor Good Very poor Poor.
Colby :Good Good Fair Fair Poor Very poor Good Very poor Fair.
B3': Very oor Fair.
Wiley {Fair Good Fair Fair Poor Very poor Fair P
Colby :Fall- Good Fair Fair Poor Very poor Fair Very poor Fair.
* See map unit description for the composition and behavior of the map unit.
** Potential for grain and seed crops, grasses and legumes, and for openland wildlife based on irrigated
land use.
WELD COUNTY, COLORADO, SOUTHERN PART 127
TABLE 12.--ENGINEERING PROPERTIES AND CLASSIFICATIONS--Continued
T Classification Frag- Percentage passing
Soil name and ;Depth USDA texture ments sieve number-- :Liquid Plas-
map symbol Unified AASHTO 1 3 I limit ticity
inches 4 10 40 200 index
I In Pct Pct
56, 57 0-9 Clay loam CL A-6 0 05-100;80-100 80-95 70-80 25-40 10-20
Renohill 9-32 Clay, clay loam CL, CH A-7, A-6 0 95-100:90-100 90-100 75-95 35-65 20-35
32 Weathered --- --- --- --- --- ---
bedrock.
58, 59 0-6. Loam i------ CL-ML A-4 0-5 75-100 75-100 70-95 55-75 25-35 5-10
Shingle 6-18 Clay loam, loam CL A-6 0 75-100 75-100 65-100 50-80 30-40 10-20
`, 18 Unweathered --- --- --- --- --- --- --- ---
bedrock.
60*:
Shingle 0-6 Loam CL-ML A-4 0-5 75-100 75-100 70-95 55-75 1 25-35 5-10
6-18 Clay loam, loam CL A-6 0 75-100 75-100 65-100 50-80 30-40 10-20
18 Unweathered --- --- --- --- --- --- --- --- ---
bedrock.
Renohill 0-9 Clay loam CL A-6 0 85-100 80-100 80-95 70-80 25-40 10-20
9-32 Clay, clay loam CL, CH A-7, A-6 0 95-100 90-100 90-100 75-95 35-65 20-35
32 Weathered --- --- --- --- --- ---
bedrock.
61 0-11 Fine sandy loam ML, SM A-4 0 95-100 90-100 70-95 40-65 20-35 NP-5
Tassel 11 Unweathered .-- --- --- --- --- --- --- --- ---
bedrock.
62, 63 0-6 Fine sandy loam SM, ML A-2, A-4 0-5 75-100 75-100 70-90 30-60 --- NP
Terry 6-18 Fine sandy loam, SM, ML A-4 0 75-100 75-100 70-85 40-60 --- NP
sandy loam.
18-37 Fine sandy loam, SM A-2, A-4 0-5 75-100 75-100 70-85 25-50 --- NP
-- sandy loam,
loamy fine
sand.
37 Weathered --- --- --- --- --- ---
bedrock.
64, 65 0-8 Loam 1CL-ML A-4 0-5 80-100 75-100 70-95 50-75 20-30 5-10
Thedalund
8-25 Clay loam, loam,;CL-ML, A-6, A-V 0-5 80-100 75-100 70-95 40-80 25-35 5-15
very fine sandy: CL,
loam. I SM-SC,
SC
/ 25 Weathered --- --- --- --- --- --- ---
bedrock.
66, 67 0-5 Clay loam CL A-6 0-5'• 95-100 95-100 80-100 70-80 30-40 10-15
Ulm 5-19 Clay loam, clay ICL A-6, A-7 0-5 75-100 75-100 75-100 60-80 35-45 20-30
19-60 Clay loam ICL A-6 0-5 75-100 75-100 75-100 60-80 30-40 15-20
68* 0-60 Variable ; --- --- --- --- --- --- --- --- ---
Ustic
To rrio rt hen is
- 69, 70 0-8 :Fine sand ;SM A-2 0 100 100 80-95 10-30 --- NP
Valent 8-601Fine sand, sand ISP-SM, SM A-2, A-3 0 100 95-100 75-90 . 5-20 --- NP
71*:
Valent 0-8 ;Fine sand ISM, A-2 0 100 100 80-95 10-30 --- NP
.. 8-601FFine sand, sand ISP-SM, SM A-2, A-3 0 100 95-100 75-90 5-20 --- NP
Loup 0-161Loamy sand ;SM A-2 0 100 100 50-100 15-30 , --- NP
16-60:Fine sand, loamy:SF-SM, SM A-2, 4-3 0 100 100 65-100 5-20 --- NP
sand, sand.
See footnote at end of table.
128 SOIL SURVEY
TABLE 12.--ENGINEERING PROPERTIES AND CLASSIFICATIONS--Continued
Classification Frag- Percentage passing
Soil name and Depth USDA texture ments sieve number-- Liquid Plas-
map symbol Unified AASHTO > 3 limit ticity
inches 4 10 40 1 200 index
Pot Pct
72, 73, 74 0-6 Loamy sand ;SM A-2 0 100 ;90-100 60-90 115-30 --- NP
Vona 6-28 Fine sandy loam,ISM A-2, A-4 0 100 190-100 60-90 130-45 --- NP
sandy loam.
28-60 Sandy loam, ISM A-2 0 100 190-100 50-85 115-30 --- NP
loamy sand. -
75, 76, 77 0-6 Sandy loam SM A-2, A-4 0 100 190-100 60-90 130-45 --- NP
Vona 6-28 Fine sandy loam, SM A-2, A-4 0 100 :90-100 60-90 ;30-45 --- . NP
sandy loam.
28-60 Sandy loam, ISM A-2 0 100 190-100 50-85 115-30 --- NP
loamy sand. 1
78, 79, 80 0-8 Loam ,ML, A-4 0 100 . x
'1195-100 85-100160-85 20-30 NP-10
Weld CL-ML
8-15 Silty clay loam, CL A-6, A-7 0 100 1 100 95-100:85-95 35-50 15-30
silty clay.
15-60 Silt loam, loam CL-ML, CL A-4, A-6 0 100 ;95-100 85-100160-85 20-35 5-15
•
81', 82+, 83':
Wiley 0-11 Silt loam CL-ML, CL A-4, A-6 0 100 : 100 90-100170-90 25-35 5-15
11-60 Silty clay loam, CL A-6 0 100 1 100 90-100170-95 25-35 10-20
silt loam.
Colby 0-7 Loam CL-ML A-4 0 100 100 90-100:85-100 25-30 5.10
7-60 Silt loam, loam CL-ML A-4 - 0 100 1 100 90-100185-100 25-30 5-10
a See map unit description for the composition and behavior of the map unit.
I
WELD COUNTY, COLORADO, SOUTHERN PART 131
TABLE 13.--PHYSICAL AND CHEMICAL PROPERTIES OF SOILS--Continued
Risk of corrosion Erosion Wind
Soil name and :Depth, Permea- Available Soil Salinity Shrink- factors erodi-
map symbol , bility water reaction swell Uncoated Concrete bility
capacity potential steel K T group
In In/hr In/in 1'N Mmhcs/cm
60*:
Renohill 0-9 0.2-0.6 0.17-0.21 6.6-7.8 <2 Moderate High Low 0.37- 3 6
9-32 0.06-0.2 0.14-0.16 6.6-8.4 <2 High High Low 0.32
32 ___ ___
^ 61 0-11 2.0-6.0 0.16-0.18 7.4-8.4 <2 Low High Low 0.24 1 3
Tassel 11 --- ---
62, 63 0-6 2.0-6.0 0.13-0.15 7.0-7.8 <2 Low Moderate Low 0.20 2 3
Terry. 6-18 2.0-6.0 0.13-0.15 7.0-7.8 <2 Low Moderate Low 0.20
18-37 2.0-6.0 0.13-0.15 7.9-8.4 <2 Low High Low 0.20
37 ___
64, 65 0-8 0.6-2.0 0.16-0.18 7.9-8.4 <2 Low High Low 0.32 2 4L
Thedalund 8-25 0.6-2.0 0.16-0.18 7.9-8.4 <2 Low High Low 0.32
25 ___ ---
66,
67 0-5 0.6-2.0 0.16-0.18 6.6-7.8 --- Low High Low 0.32 5 6
Ulm 5-19 0.06-0.2 0.19-0.21 7.4-8.4 <2 High High Low 0.37
19-60 0.6-2.0 0.19-0.21 7.9-8.4 <2 Moderate High Low 0.37
68* 0-60
U stic
Torriorthents
69, 70 0-8 6.0-20 0.07-0.12 6.6-7.3 --- Low Low Low 0.10 5 1
Valent 8-60 6.0-20 0.05-0.10 6.6-7.8 <2 Low Low Low 0.10
71*:
Valent 0-8 6.0-20 0.07-0.12 6.6-7.3 --- Low Low Low 0.10 5 1
8-60 6.0-20 0.05-0.10 6.6-7.8 <2 Low Low Low 0.10
Loup 0-16 6.0-20 0.10-0.14 6.6-8.4 <2 Low High Low 0.17 5 2
16-60 6.0-20 0.06-0.08 7.4-8.4 <2 Low High Low 0.17
72, 73, 74 0-6 6.0-20 0.09-0.11 6.6-7.3 --- Low Low Low 0.10 5 2
Vona 6-28 2.0-6.0 0.12-0.14 6.6-8.4 <4 Low High Low 0.10
28-60 6.0-20 0.08-0.11 7.4-8.4 <4 Low - High Low 0.10
75, 76, 77 0-6 2.0-6.0 0.11-0.13 6.6-7.3 --- Low Low Low 0.10 5 3
Vona 6-28 2.0-6.0 0.12-0.14 6.6-8.4 <4 Low High Low 0.10
28-60 6.0-20 0.08-0.11 7.4-8.4 <4 Low High Low 0.10
78, 79, 80 0-8 0.6-2.0 0.16-0.21 6.6-7.3 <2 Low Low Low 0.32 5 6
Weld 8-15 0.06-0.2 0.19-0.21 6.6-7.8 <2 High Moderate Low 0.28
15-60 0.6-2.0 0.16-0.21 7.4-8.4 <2 Low High Low 0.28
81*, 82*, 83*:
Wiley 0-11 0.6-2.0 0.19-0.21 7.4-7.8 <2 Low High Low 0.37 5 4L
11-60 0.6-2.0 0.19-0.21 7.9-8.4 <2 Moderate High Low 0.37
Colby 0-7 0.6-2.0 0.20-0.24 6.6-8.4 <2 Low Moderate Low 0.37 5 4L
- 7-60 0.6-2.0 0.17-0.22 7.4-8.4 <2 Low Moderate Low 0.37
* See map unit description for the composition and behavior of the map unit.
•
WELD COUNTY, COLORADO, SOUTHERN PART 133
TABLE 14.--SOIL AND WATER FEATURES--Continued
' Flooding High water table Bedrock
Soil name and Hydro-I Potential
map symbol logic Frequency Duration Months I Depth Kind Months Depth Hard- frost
group ness action
Ft In
I
36*:
Shingle D None --- --- >6.0 --- --- 10-20 Rip- Low.
pable
37, 38 B None ---
___ >6.0 --- --- 20-40 Rip- Low.
Nelson pable
39, 40, 41, 42, -_- >60 --- Moderate.
43 C None --- --- >6.0 ---
Nunn
44, 45, 46, 47, ___ >60 --- Low.
48 B None --- --- >6.0 ---
Olney
49 A None ___ ___ >6.0 --- ___ >60 --- Low.
Osgood
50, 51, 52, 53---- B None --- --- >6.0 --- --- >60 --- Low.
Otero
54, 55 B None to rare --- --- >6.0 --- --- >60 --- Moderate.
Paoli
56, 57 C None --- --- >6.0 --- --- 20-40 Rip- Low.
Renohill pable
58, 59 0 None --- --- >6.0 --- --- 10-20 Rip- Low.
Shingle pable
60': ___ >6.0 ___ 10-20 Rip- Low.
Shingle D None -- pable
Renohill C None --- --- >6.0 --- --- 20-40 Rip- Low.
gable
61 D None --- --- >6.0 --- --- 10-20 Rip- Low.
Tassel pable
62, 63 B None --- --- >6.0 --- --- 20-40 Rip- Low.
pable
Terry
64, 65 ' C None --- --- >6.0 --- --- 20-40 Rip- Low.
Thedalund pable
66, 67 0 None ___ ___ >6.0 --- --- >60 --- Low.
Ulm
68• A None --- --- >6.0 --- --- >60 --- Low.
Ustic
Torriorthents
- 69, 70 A None --- --- >6.0 --- --- >60 --- Low.
Valent
71e:
Valent A None --- --- >6.0 --- --- >60 --- Low.
Loup D Rare to Brief Mar-Jun +.5-1.5 Apparent Nov-May >60 --- Moderate.
common.
72, 73, 74, 75, >6.0 ---
76, 77 B None ---
Vona
See footnote at end of table.
134 SOIL SURVEY
TABLE 14.--SOIL AND WATER FEATURES--Continued
Flooding High water table Bedrock
Soil name and Hydro-; ; I Potential
map symbol logic; Frequency Duration ;Months 1 Depth Kind Months Depth Hard- 1 frost
• group 1 1 ness action
•
Ft In
78, 79, 80 ; C INone --- I --- I >6.0 , --- --- >60 ; --- ;Moderate.
Weld
i ;
81■ 82•, 83•: I I 1
Wiley -----1 B (None --- --- I >6.0 1 --- --- 1 >60 --- Low.
1 •I 1 '
Colby 1 B (None --- --- 1 >6.0 --- - ; >60 1 --- Low.
• See map unit description for the composition and behavior of the nap unit.
lierracon
1242 Bramwood PI
Longmont,Colorado 80501
(303)776-3921 Fax_(303)776-4041
January 19, 2001
Mr. Chris Varra
Varra Companies, Inc.
P.O. Box 2049
Broomfield, Colorado 80038-2049
Re: General Subsurface Conditions
South 1/2 of the Northwest 1/4 Section 25, T1N, R68 West
Weld County Roads 6 and 11
Weld County, Colorado
Terracon Project No. 22015001
As requested, Terracon completed a limited subsurface study for the project site on January
16, 2001. The field investigation consisted of drilling, sampling and logging three (3) test
borings to depths of about 10 to 15 feet. The approximate locations of the test borings are
shown on the attached Boring Location Plan. Groundwater conditions were recorded in each
boring at the time of drilling.
Samples retrieved during the field exploration were returned to the laboratory for observation
by the project geotechnical engineer and were visually or manually classified in general
accordance with the Unified Soil Classification System. Samples of bedrock were classified in
accordance with the general notes for Rock Classification.
Subsurface Conditions: In general, our borings encountered approximately five (5) to six (6)
feet of fat to lean clays with varying amounts of sand. Sedimentary bedrock was encountered
below the overburden clays and these materials extended to the maximum depths explored.
The bedrock consisted primarily of moderate to high plasticity claystone, although occasional
siltstone/sandstone interbeds were present in Borings 1 and 2. The claystone in Borings 2 and
3 contained some lignitic/carbonaceous materials.
No groundwater was encountered in the borings to the depths explored immediately after
drilling. These observations represent groundwater conditions at the time of the field
exploration, and may not be indicative of other times, or at other locations. Groundwater
conditions can change with varying seasonal and weather conditions, and other factors. Zones
of perched and/or trapped groundwater may also occur at times in the subsurface soils
overlying bedrock, on top of the bedrock surface or within permeable fractures in the bedrock
materials. The location and amount of perched water is dependent upon several factors,
Arizona ■Arkansas ■Colorado ■Georgia MI Idaho■Illinois I•Iowa IN Kansas ■Kentucky •Minnesota•Missouri
Montana •Nebraska ■Nevada ■New Mexico •Oklahoma ■Tennessee ■Texas ■Utah ■Wisconsin■Wyoming
Quality Engineering Since 1965
General Subsurface Conditions Terracon
South'A of the Northwest'/ Section 25,TIN,R68 West
Weld County Roads 6 and 11
Weld County,Colorado
Terracon Project No.22015001
including hydrologic conditions, type of site development, irrigation demands on or adjacent to
the site, fluctuations in water features, seasonal and weather conditions.
Field and Laboratory Test Results: Field penetration test results indicate that the clay soils
are typically hard in consistency. Results of gradation and plasticity tests indicate that the clay
sample tested has a Plasticity Index of 42 and contains about 88 percent fines (material
passing the No. 200 sieve). The sample tested classifies as an A-7-6 soil according to the
AASHTO classification system. An AASHTO group index of 40 was determined for the sample
tested. The sample tested has a "CH" classification in accordance with the Unified Soil
Classification System (USCS) methods. Based on physical property tests, penetration
resistance values and on our experience with similar soils, we judge the clays to have
moderate to high swell potential when wetted.
Gradation and index property tests indicate that the claystone bedrock sample tested has a
Plasticity Index of 66 and contains about 99 to 100 percent fines (material passing the No. 200
sieve). Penetration resistance measurements indicate that the unweathered bedrock varies
from medium to hard in hardness. Based on our experience in the area, we judge the
claystone bedrock to have moderate to high swell potential.
Geology: The project area is located within the Colorado Piedmont section of the Great Plains
physiographic province. The Colorado Piedmont, formed during Late Tertiary and Early
quaternary time (approximately two-million (2,000,000) years ago), is a broad, erosional trench
which separates the Southern Rocky Mountains from the High Plains. Structurally, the site lies
along the western flank of the Denver Basin. During the Late Mesozoic and Early Cenozoic
Periods (approximately seventy million (70,000,000) years ago), intense tectonic activity
occurred, causing the uplifting of the Front Range and associated downwarping of the Denver
Basin to the east. Relatively flat uplands and broad valleys characterize the present-day
topography of the Colorado Piedmont in this region.
Bedrock conditions mapped in the vicinity of the site (1Tweto, 1979) consist of the Laramie
Formation (KI) which commonly includes shale, claystone, sandstone and coal beds. The
formation has been an important source for underground mining of coal in the past. Mapping
completed by the Colorado Geological Survey (2Amuedo and Ivey, 1975), indicates that the
Tweto, Ogden, 1979 Geologic Map of Colorado, United States Geological Survey.
2Amuedo & Ivey, 1975, Ground Subsidence and Land-Use Considerations Over Coal Mines in the Boulder-Weld Coal
Field, Colorado, Colorado Geological Survey, Environmental Geology No. 9.
2
General Subsurface Conditions Terracon
South 1/2 of the Northwest Y.Section 25,T1N,R68 West
Weld County Roads 6 and 11
Weld County,Colorado
Terracon Project No.22015001
property does not fall within the subsidence hazard boundaries as defined by the Amuedo and
Ivey study. Evaluation of risk associated with subsidence at the site is beyond the scope of this
report. If the owner is concerned about the potential for such subsidence hazards, other
studies should be undertaken.
Mapping completed by the Colorado Geological Survey ('Hart, 1972), indicates the site in an
area of "High Swell Potential" Potentially expansive materials mapped in this area include
bedrock, weathered bedrock and colluvium (surficial units).
We appreciate the opportunity to be of service to you on this phase of the project. If you have
any questions concerning this letter, or if we may be of further service to you, please do not
hesitate to contact us.
o�pp0••• fre ,
•S.
Sincerely, c�; � S. WI1�N9ot�,
TERRACON : 27741 • 5
•
0o •
tFS�IGNAL �ver
Eric S. Willis, P.E.
Geotechnical Engineer/Department Manager
Copies to: Addressee (2)
'Hart, Stephen S., 1972, Potentially Swelling Soil and Rock in the Front Range Urban Corridor, Colorado, Colorado
Geological Survey, Environmental Geology No. 7.
3
1
�a�
eti z
e rP.2 z
Qe
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0
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GKA✓CL ROAD
N
LEGEND
k .t =iicl,O
APPROJ(IMATC LOCATION OF VARRAGOMPANl�5,INC.
S TCST PORING DRl/I FO ON 11 5UP5URFAGC GONDITION5
JANUARY IG,2001 5 I/2 OF Pit NW 1/4;5tG 25,TIN,RGBW
WELD COUNTY,COLORADO
FOURC 1:POKING LOCATION PLAN
Pro3ect Nonoger� CSy' Project No. 22QI0OI
Drawn By KL ber ratanscolei I„-400'
Checked By C14y 1242 Branwood PlaceBate, I�18/01
RI CEB 5-19-99 Longmont, Colorado 00501
DIAGRN115 FOR GCNCRAL LOGATCN ONLY,AND l5 NOT/NTCNDCD Mr CON5TRUCTCN PURPO5C5 R0 CHS 4-22-98 Approved By tSW 303-776-3921 Sheet No. (off
LOG OF BORING NO. TB-1
Page Iof1
OWNER/CLIENT ARCHITECT/ENGINEER
Varra Companies, Inc.
SITE S 1/2 of the NW 1/4; Sec 25, TIN, R68W PROJECT
Weld County, Colorado Subsurface Conditions
SAMPLES TESTS
o 0 Z > y O
o
= DESCRIPTION K 2
0 I- z Z Z cn= 0 U_
W m z rL .] ..
m F p [�
w U a Z - � k 8g� 5za mm�'
Approx. Surface Elev.: GRADE ft. o z f>-: Oujda' C e `:4 .9 s 3
0.5'TOPSOIL, soil with light vegetation and /
root growth. 1 _
FAT CLAY, slightly sandy, brown, hard, ! —
slightly moist, calcareous. CH
5
6,0 _ SS 45/12
CLAYSTONE, moderate to high plasticity,
gray, olive gray, tan, rust, weathered to
medium hard, with siltstone/sandstone
interbeds. 10 SS 48/12
11.0
BOTTOM OF BORING
-. THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 1-16-01
WL 2 Dry 1/16/01 i BORING COMPLETED 1-16-01
WL lierracon RIG JW
CME-55 FOREMAN
WL APPROVED EJP JOB# 22015001
LOG OF BORING NO. TB-2 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
Varra Companies, Inc.
SITE S 1/2 of the NW 1/4; Sec 25, TiN, R68W PROJECT
Weld County, Colorado Subsurface Conditions
SAMPLES TESTS
a
o } t2i z
DESCRIPTION t m H w cn Z n= V U E
z ¢ et z LU 3 5
w �n C } Z .0 C 541 nU ZondLu p " G dwrCn
o Approx. Surface Elev.: GRADE ft. o z F am 7 C o. D U ri, [.. v,
0.5 TOPSOIL, soil with light vegetation and r
lroot growth. ! —
CL CH
LEAN TO FAT CLAY, slightly sandy,
%
5.0 brown, light brown, dry to slightly
moist, calcareous, _
5—
CLAYSTONE, moderate to high plasticity, —
gray, light gray, rust, weathered to
medium hard, with siltstone/sandstone `
interbeds, slightly lignitic and 10 SS 45/12
carbonaceous.
13.0 -
CLAYSTONE/SILTSTONE, rust, orange
brown, slightly moist to moist, hard. 15 SS 50/9
[6.0
BOTTOM OF BORING
- THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS - BORING STARTED 1-16-01
WL Si Dry I/16/01. 1 BORING COMPLETED 1-16-01
WL
err acon RIG CME-55 (FOREMAN JW
WL APPROVED EJp JOB 11 22015001
LOG OF BORING NO. TB-3 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
Varra Companies, Inc.
SITE S 1/2 of the NW 1/4; Sec 25, T1N, R68W PROJECT
Weld County, Colorado Subsurface Conditions
SAMPLES TESTS
o0 w � o
DESCRIPTION t m F us y Z co x J c
74
w y LU ° c CGu Z p 3n
J Approx. Surface Elev.: GRADE ft. C w z r- a. m Q e w U rn _ r
0.5 TOPSOIL, soil with light vegetation and
\ root growth. 1
11
LEAN TO FAT CLAY, slightly sandy, CL'CH SS 50/10
brown, dry to slightly moist, hard,
calcareous.
/ 5
6.0
I SS 50/10
10-
CLAYSTONE, moderate to high plasticity, —
gray, rust, weathered to hard, slightly
lignitic and carbonaceous.
I
15 SS 50/9
16.0
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 1-16-01
WL 2 Dry 1/16/01 1 BORING COMPLETED 1-16-01
WL llerraccn RIG Cb1E$5 FOREMAN JW
WL APPROVED EJP JOB 1/ 22015001
U.S.SIEVE PENING IN LW_ .o I U.S.SIEVE NUMBERS HYDROMETER
O
r
]00 6 4 3 2 1.5 1 3/4 1/3 3/8 3 6 810 1416 1, 30 .0 50 70 100140 200
1
i 11111011111dalli a° rei11ll11iIII I
90■ II-____Iii 1II _ll■ II Ill MUM MI■ I
80 IIIliiII liii_-liii
■ IIiiI1 _MINIMI I
R 70■ HiiII- - ll1,i1i■I -,
E •■ III MI Mill 11111111
TN 60•II II� MIMI MIN MN 1
F ■ II__lit_ N.1111_liii
E 50 II11__11 ' �liii__IiIlB ■ IliiII 111111111�
1\ 40 Ill1
MINI M II11I III111I�
WEr
IIII��NI r®11I MI■I�
G 30 E. ir��111 WHIM MIMI 1
T II IIIIII 11 X1111 51■1
■ 11 Ili MINI_MI I_
_111 ®1111 MIAI�
10.. 111111111111111111111111111111111111
111111111=1111111=111111111111111 i
0■ 100 10 11M�III 11111 MIN
1 0.1 0.01
GRAIN SIZE IN MILLIMETERS
COBBLES GRAVEL SAND
coarse I fine coarse ! medium I tine SILT OR CLAY
S.ecimen Identification Classification MC% LL PL PI Cc Cu
E TB-1 5.0 Fat Cla CH 62 20 42 -
iTB-3 8.0 91 25 66
S,ecimen Identification %Silt j %Clay
• TB-1 5.0 4.75 0.0 12.3 87.7
MI TB-3 8.0 4.75 0.0 1 99.7 PROJECT Subsurface Cond'tians -S 1/2 of the NW 1/4; JOB NO. 22015001
Sec 25, T1N, R68W DATE 1/19/01
GRADATION CURVES
Terracon
Longmont. Colorado
GENERAL NOTES
DRILLING &SAMPLING SYMBOLS:
SS: Split Spoon- 1-3/8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger
ST: Thin-Walled Tube-2/" I.D., unless otherwise noted PA: Power Auger
RS: Ring Sampler-2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger
CB: California Barrel — 1.92" I.D., 2.5" O.D. RB: Rock Bit
BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary
The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch
penetration with a 140-pound hammer falling 30 inches is considered the"Standard Penetration" or"N-value".
WATER LEVEL MEASUREMENT SYMBOLS:
WL: Water Level WS: While Sampling
WCI: Wet Cave in WD: While Drilling
DCI: Dry Cave in BCR: Before Casing Removal
AB: After Boring ACR: After Casing Removal
Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at
other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of
groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-
term observations.
DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils
have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or
sand. Fine Grained Soils have less than 50% of their dry weight retained on a#200 sieve; they are principally described as clays
if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor
constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained
soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.
CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS
Standard
Unconfined Penetration or Standard Penetration
Compressive N-value(SS) or N-value(SSI
Strength, Qu, psf Blows/Ft. Consistency Blows/Ft. Relative Density
< 500 <2 Very Soft 0—3 Very Loose
500 - 1,000 2-3 Soft 4-9 Loose
1,001 - 2,000 4-6 Medium Stiff 10-29 Medium Dense
2,001 - 4,000 7-12 Stiff 30-49 Dense
4,001 - 8,000 13-26 Very Stiff 50+ Very Dense
8,000+ 26+ Hard
RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY
Descriptive Term(s) of other Percent of Major Component
constituents Dry Weight of Sample Particle Size
Trace < 15 Boulders Over 12 in. (300mm)
With 15—29 Cobbles 12 in. to 3 in. (300mm to 75 mm)
Modifier > 30 Gravel 3 in. to#4 sieve(75mm to 4.75 mm)
Sand #4 to#200 sieve(4.75mm to
RELATIVE PROPORTIONS OF FINES Silt or Clay 0.075mm) Passing#200 Sieve
(0.075mm)
Descriptive Term(s) of other Percent of PLASTICITY DESCRIPTION
constituents Dry Weight
Term Plasticity Index
Trace < 5 Non-plastic 0
With 5- 12 Low 1-10
Modifiers > 12 Medium 11-30
High 30+
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UNIFItD SOIL CLASSIFICATION S\ IEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests" Soil Classification
Group
Symbol Group Name
Coarse Grained Soils Gravels Clean Gravels Cu≥4 and 1 ≤Cc≤36 GW Well-graded gravelF
More than 50%retained More than 50%of coarse Less than 5%(fines° Cu<4 and/or 1 >Cc>3E GP Poorly graded gravelF
fraction retained on
on No.200 sieve No.4 sieve Gravels with Fines More Fines classify as ML or MH GM Silty gravelF•c'"
than 12%fines` Fines classify as CL or CH GC Clayey gravelF.c."
Sands Clean Sands Cu≥6 and 1 ≤Cc≤3E SW Well-graded sand'
50%or more of coarse Less than 5%f nes° Cu<6 and/or 1 >Cc>35 SP Poorly graded sand'
fraction passes
No.4 sieve Sands with Fines Fines classify as ML or MH SM Silty sand"'
More than 12%fines° Fines Classify as CL or CH SC Clayey sand"I
Fine-Grained Soils Silts and Clays inorganic PI>7 and plots on or above"A"line' CL Lean clay'CLM
50%or more passes the Liquid limit less than 50 PI<4 or plots below"A"line' ML SiltKLM
No.200 sieve
organic Liquid limit-oven dried M"Organic clays L
<0.75 OL
Liquid limit-not dried Organic siltKI-M°
Silts and Clays inorganic PI plots on or above"A"line CH Fat clayKLM
Liquid limit 50 or more PI lots below"A"line MR Elastic Silt"M
organic Liquid limit-oven dried Organic clayK°MP
0.75 OH
Liquid limit-not dried Organic siltK`.M°
Highly organic soils Primarily organic matter,dark in color,and organic odor PT Peat
"Based on the material passing the 3-in.(75-mm)sieve "If fines are organic,add"with organic fines"to group name.
a If field sample contained cobbles or boulders,or both,add"with cobbles or ' If soil contains≥15%gravel,add"with gravel"to group name.
boulders,or both"to group name. 'If Atterberg limits plot in shaded area,soil is a CL-ML,silty clay.
Gravels with 5 to 12%fines require dual symbols: GW-GM well-graded K If soil contains 15 to 29%plus No.200,add"with sand"or"with
gravel with silt, GW-GC well-graded gravel with clay,GP-GM poorly graded gravel,"whichever is predominant.
gravel with silt, GP-GC poorly graded gravel with clay. `If soil contains≥30%plus No.200 predominantly sand,add"sandy'
°Sands with 5 to 12%fines require dual symbols: SW-SM well-graded sand to group name.
with silt,SW-SC well-graded sand with clay,SP-SM poorly graded sand MIf soil contains≥30%plus No.200,predominantly gravel,add
with silt, SP-SC poorly graded sand with clay "gravelly'to group name.
(D3°)2 "PI≥4 and plots on or above"A"line.
E Cu=DadD1° Cc= °PI <4 or plots below"A"line,
Dm X Ds°
F If soil contains≥ 15%sand,add"with sand"to group name. F PI plots on or above"A"line.
°If fines classify as CL-ML, use dual symbol GC-GM,or SC-SM. °PI plots below"A"line.
60 I
For classification of fine-grained
soils and fine-grained fraction
50 of coarse-grained soils \,4` ' eEquation of"A"-line +J, , •P
a Horizontal at PI=4 to LL=25.5.
X 40 then PI=0.73(LL-20) O'r
C3 Equation of"U"-line Goo
Z Vertical at LL=16 to PI=7,
>- 30 - then P1=0.9(LL-8)
H
U O
0
coH 20 j G.
MH or OH
a-
10
7 l CL- hAL
4 ML or OL
a -
I
0 10 16 20 30 40 50 60 70 80 90 100 110
LIQUID LIMIT(LL)
lierracon _
Form 111-6/98
ROCK CLASSIFICATION
(Based on ASTM C-294)
Sedimentary Rocks
Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be
composed of particles of pre-existing rocks derived by mechanical weathering, evaporation or by
chemical or organic origin. The sediments are usually indurated by cementation or compaction.
Chert Very fine-grained siliceous rock composed of micro-crystalline or crypto-
crystalline quartz, chalcedony or opal. Chert is various colored, porous to
dense, hard and has a conchoidal to splintery fracture.
Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any
rock containing clay. Soft massive; gray, black, brown, reddish or green and
may contain carbonate minerals.
Conglomerate Rock consisting of a considerable amount of rounded gravel, sand and cobbles
with or without interstitial or cementing material. The cementing or interstitial
material may be quartz, opal, calcite, dolomite, clay, iron oxides or other
materials.
Dolomite A fine-grained carbonate rock consisting of the mineral dolomite [CaMg
(CO3)z1. May contain noncarbonate impurities such as quartz, chert, clay
minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid
(HCL).
Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaCo3). May
contain noncarbonate impurities such as quartz, chert, clay minerals, organic
matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL).
Sandstone Rock consisting of particles of sand with or without interstitial and cementing
materials. The cementing or interstitial material may be quartz, opal, calcite,
dolomite, clay, iron oxides or other material.
Shale Fine-grained rock composed of, or derived by erosion of silts and clays or any
rock containing clay. Shale is hard, platy, or fissile may be gray, black,
reddish or green and may contain some carbonate minerals (calcareous shale).
Siltstone Fine grained rock composed of, or derived by erosion of silts or rock
containing silt. Siltstones consist predominantly of silt sized particles (0.0625
to 0.002 mm in diameter) and are intermediate rocks between claystones and
sandstones, may be gray, black, brown, reddish or green and may contain
carbonate minerals.
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