Soil Maps & Technical Information
United States Geological Survey
Aerial photos often reveal evidence of unsuspected development or manipulation of the site. A great source for this type of information is a topographic map from the United States Geological Survey.
Go to the Geo-Data Explorer sub page, http://topomaps.usgs.gov/, and you will be amazed at what you can map.
National Soil Survey Center (NSSC)
The NSSC works closely with several federal and state agencies, land grant universities, and private entities as part of the National Cooperative Soil Survey (NCSS).
The NCSS produces soil surveys to help people understand soils and their responses to a variety of natural and human influences. A soil survey is a multi-purpose, science-based inventory of the distribution and properties of soils and factors affecting the soil environment. Soil surveys include predictions of soil behavior related to uses in an urban, agronomic, or natural environment.
Here is a link to their site:
State Soil Geographic Database (STATSGO)
State general soil maps made by generalizing the detailed soil survey data. The level of mapping is designed to be used for broad planning and management uses covering state, regional, and multi-state areas. STATSGO data are designed for use in a Geographic Information System (GIS).
FM 5-410 - Military Soils Engineering
Construction in the theater of operations is normally limited to roads, airfields, and structures necessary for military operations. This manual emphasizes the soils engineering aspects of road and airfield construction. The references give detailed information on other soils engineering topics that are discussed in general terms. This manual provides a discussion of the formation and characteristics of soil and the system used by the United States (US) Army to classify soils. It also gives an overview of classification systems used by other agencies. It describes the compaction of soils and quality control, settlement and shearing resistance of soils, the movement of water through soils, frost action, and the bearing capacity of soils that serve as foundations, slopes, embankments, dikes, dams, and earth-retaining structures.