The TRPA are pro-river activists from across the state representing landowner coalitions, conservationists, canoe clubs, and fishing associations. Their protection efforts include promoting conservation and performing cleanup along heavily used rivers.
This site not only has a wealth of information about the Hill Country Rivers (among dozens of other rivers) but also is a good source for kayak and canoe enthusiasts. Look for a called “River Descriptions”, you will be able to select “Texas” and then which specific river you are interested in.
Kevin Hutchison recently updated the venerable “Fly-Fishing the Texas Hill Country” by Bud Priddy. A great guide to fishing and lodging on Texas rivers. I highly recommend purchasing a copy if you are interested in fly fishing the Hill Country.
The Guadalupe-Blanco River Trust is a nonprofit land trust organization that was developed to conserve land in the Guadalupe River Watershed for its natural, recreational, scenic, historic and productive value. It was founded in 2001 by the Guadalupe-Blanco River Authority, a conservation and reclamation district created in 1933 by the Texas Legislature. The Upper Guadalupe River Authority (UGRA) has also partnered with the Trust.