This investigation will help you to:
Soil Quality Resource Concerns: Available Water Capacity, NRCS
This PDF (you must have Adobe Acrobat to view this file) looks at the properties that affect water availability in soil and how soil influences water quality.
Soil Sample Instructions, NRCS
Good web site for procedural information on taking soil samples.
Surf Your Watershed, EPA
This site offers links to a wide range of data on environmental conditions.