Water is so important to the Buffalo River.  As obvious as that statement sounds, I haven't seen anywhere else where it is more true.  The river changes constantly with rain or without.  It is one place to visit with a full river, and a completely different one when the water runs dry.  Here are some of the best guides to use to see what Buffalo River will greet you if go to visit.

Water Level (Air Space) at Ponca Bridge

NPS River and Rain Reports

USGS River Gage near Boxley

USGS River Gage at Ponca Bridge

USGS Gage at Pruitt

USGS Gage on Richland Creek

Here is some other information that can come in handy when planning a trip to the area.  There isn't much on the web about the Buffalo that's really useful, but these few sites can help tremendously.

National Park Service Page

Cloudland - Tim Ernst's Website

Buffalo Outdoor Center

Ozark Mountain Region Tourism