Well guys, took the family over to San Marcos to check out the sub running possibilities. Here is my review of the San Marcos river (on a scale of 1 - 5):
Water clarity: 5 Infinite visibility, simply the clearest water in the state.
Depth: 3 Pretty good during most of the observation (5-7 feet). There were some pools where the bottom was much deeper.
Current: 2-3 The springs are pumping out tons of water and it moves through the parks at a good clip -- much stiffer than at San Gab. It ranged from small rapids to smooth, but well moving, water. Runs times would be greatly diminished.
Area(s) of operation: 2-3 The river snakes through the town and is lined with various parks. The width at it's widest is 75% that of the San Gabriel park area.
Unfortunately, most of this is covered by thick patches of weeds. The stalks are up to 20 feet long and trail downstream in the current. While there are some open areas, if a boat got lost in there it would be mighty hard to find.
While the parks were pretty much uninhabited, they gave signs of hard use. Saw several kayakers paddling today. Tubing is conducted throughout the summer through most of the potential running areas.
Accessability: 1 I found minimal launch areas in the locations where running was optimal. There were two lcoations with nice concrete walls with steps into the water: a park where the bottom was literally covered with weeds and at the tube rental jump-off spot. I personally don't envision navigating around the tubers in the late summer.
Facilities: 3-4 Several parks had nice pavilions with restrooms, fairly close parking. Didn't check on power access though. There were plenty of places to stay and eat. It was a 2 hour drive from NW Houston.
MY OVERLL RATING OF SAN MARCOS RIVER: 2 I took my LA ready to run and didn't bother.
Regarding Aquarena Springs -- The park closed in 1996 and is in underfunded transition into a Texas Rivers Museum/Science Center. Owned by Texas State University, the only attraction left working is the glass bottom boats. The old hotel with water access is now being converted into museum and office space. The area from the park water front south to the dam has been reverted into a wetlands area. Completely overgrown with weeds. The area on the old park waterfront has no launching access, is extrememly deep and clogged with towering weeds. A glass bottom boat plods through the area every 30 minutes.
On the hotel side of the lake there are the remains of several trails which lead to the water. Boats could be launched there but it would be a stretch and there is no easy access to getting to it other than lugging everything down to the water's edge. Again, the water is shockingly clear -- 3 times purer than the EPA's minimum standard for water purification as it exits the springs on the bottom. You can see straight to the bottom 30 feet down where the weeds permit.
MY OVERALL RATING FOR AQUARENA SPRINGS: 1
This review covers the San Marcos river from the springs at the head, down to I-35.