I use this, same source but better maps with more detail
[url=http://waterdata.usgs.gov/nwis/rt:dff7b]http://waterdata.usgs.gov/nwis/rt[/url:dff7b]
or [url=http://waterdata.usgs.gov/ma/nwis/rt:dff7b]http://waterdata.usgs.gov/ma/nwis/rt[/url:dff7b] and replace the ma with your state's initials. You can click on any of the dots and get a couple of graphs that give you flow or water depth over time.

jed