Many of the engineering-geologic problems in the Arvada quadrangle are related to the unconsolidated surficial deposits, which mantle the bedrock to depths of as much as 40 or 50 feet. In this report most of the emphasis is placed on the map distribution of these materials and on a description of their physical properties. Much of the information presented on the geologic map in the form of abbreviated columnar sections is from water-well and exploration drill holes; the remainder is from foundation excavations and natural rock outcrops. A brief description of the composition and thickness of each map unit is given in the Explanation.
The generalized statements that follow, regarding the engineering properties of the map units, are based on field observations and on general performance information obtained from local engineers, contractors, builders, and property owners. It is hoped that this information, used in conjunction with the geologic map and cross sections, will be helpful to land-use planners and developers, engineers, public officials, and others in making preliminary plans and designs. It is obvious that such information cannot and should not take the place of detailed field and laboratory investigations that are required in the design of specific engineering structures.
