We recently published a toolbox that does just this you may want to check out.
Unfortunately these were developed on 9.3.1, and most of the tools do not work at 10.0 yet --
but I'm working on it!
National Water-Quality Assessment (NAWQA) Area-Characterization Toolbox
http://pubs.usgs.gov/of/2010/1268/
UPDATE: more current version
National Water-Quality Assessment (NAWQA) Area-Characterization Toolbox v2.1
https://www.arcgis.com/home/item.html?id=29707fb7f1664538871c65d7e1d9612e
Does this tool require an ArcInfo level license?