Collapsible Soil Susceptibility Map Viewer

The collapsible-soil susceptibility map viewer contains several coverages and can be confusing without an explanation of what the various coverages represent. More in-depth information on how collapsible soils are formed, what their characteristics are, and what are the inherent hazards they pose is found in the CGS publication: Collapsible Soils of Colorado

Explanation

In this map viewer there are:

Coverages from the CGS publication EG-14, Collapsible Soils of Colorado
Regional susceptibility maps from other publications
Regional maps not formally published
Basemaps

To enter the Map Viewer site,
click here.

From the Collapsible Soil of Colorado Publication (EG-14)

    The following coverages are from the map plate in the Collapsible Soils of Colorado publication. For more detail in descriptions, please see that publication.

EG-14 Evaporite formations

    Exposed evaporite rocks contain soluble minerals and are generally soft, poorly covered with vegetation, and prone to erosion. Highly collapsible soils are well known to occur in alluvial-fan and colluvial depositional systems where sediments are derived from evaporite formations.

EG-14 Cretaceous and Tertiary formations

    These poorly indurated bedrock formations, with high percentages of clay and silt, are easily eroded and sediment yield is high. Sediments derived from these formations can have the characteristics of collapsible soils when deposited in alluvial-fan, colluvial, alluvial, and eolian depositional systems.

EG-14 Dune and sheet sand deposits

    Dune and sheet sand deposits are generally an exclusion zone for collapsible soils because of the packed grain-to-grain contacts of the sand, unless that have characteristics of the eolian deposits below.

EG-14 Eolian (wind blown) loess deposits

    Loess is composed primarily of clayey to sandy silt that accumulates as blanket deposits where wind-blown dusts settles out of the air. The depositional process results in a soil structure with low density, high porosity, and a meta-stable open skeletal fabric. Loess soils are widespread in eastern Colorado and adjacent to the Front Range

EG-14 18-inch precipitation boundary

    This coverage shows that portion of Colorado where annual precipitation exceeds 18 inches. The statewide study of Colorado reveals that the higher precipitation is an exclusion zone for collapsible soils. Above 18 inches of annual precipitation, soil-saturation levels increase and potential for soil collapse comes to an end. These zones are in the mountains where winter snowpack occurs.

EG-14  Collapsible soil case history locations

    Locations of collapsible soil occurrences that were compiled for the CGS statewide collapsible soil study.

From CGS regional susceptibility maps

    The regional coverage were compiled from various CGS publications, on-line downloads, and unpublished sources. The boundaries of these regional studies is also included as a selectable coverage in the map viewer content.

Douglas County collapsible soil coverage

    This coverage is one of several on-line downloadable shapefiles for Douglas County that is part of a series available on the CGS web site here.

Collapsible soil susceptibility of the Uncompahgre River Valley area in Montrose County

    Created as part of an on-line publication that includes GIS data, which is available on the CGS website here.

Collapsible soil susceptibility of the Roaring Fork River corridor in Garfield County

    Created as a map layer for a CGS publication Map Series 34. This map can be viewed and downloaded in Adobe PDF format here.

Collapsible soil susceptibility of the Colorado River corridor in the vicinity of Rifle, Garfield County

    Created as a map layer for the CGS publication Map Series 47. This map is available from the CGS bookstore here.

Collapsible soil susceptibility map in the Rangely-Dinosaur vicinity, Rio Blanco and Moffat Counties

    Created for the Colorado Statewide study of collapsible soil. This coverage has not been published.

Collapsible soil susceptibility map of the Montezuma Valley corridor in the vicinity of Cortez, Montezuma County

    Created for the Colorado Statewide study of collapsible soil. This coverage has not been published.

Last Updated: 11/5/2012 3:31 PM