Colorado, Texas, US
|Usual Difficulty||II (for normal flows)|
|Colorado Rv at Austin, TX|
|usgs-08158000||1800 - 7000 cfs||II||00h25m||27200 cfs (too high)|
Lake Austin and Lady Bird Lake are constant-level lakes, so when the LCRA releases thousands of cfs from Mansfield Dam/Lake Travis (usually during the summer, to support agriculture downstream or to generate hydroelectric power), this water is passed through Tom Miller Dam (Lake Austin) and Lady Bird Lake (Longhorn Dam), and a 50-foot-wide ledge 50 yards below Longhorn Dam forms a wide wave-hole combination. This can also occur if upstream rainfall raises the level of Lake Austin or Lady Bird Lake beyond their maintenance levels. Refer to the LCRA Daily River Report, but note that it only lists yesterday's dam releases. Apparently LCRA does not make public today's dam releases because that information could influence energy markets. Generally the best strategy is to watch the gauge and head to the wave when the gauge starts to rise.
This wave is the only real park 'n' play surf wave in Austin, and as surf waves go, it's not bad. However, it's also somewhat high-maintenance. The gate configuration and upstream releases have to be just right for the wave to form, and as of this writing, these conditions tend to occur only for a few hours in the middle of the afternoon during the summer months. Furthermore, the water quality is relatively poor (Longhorn Dam is a top-release dam, meaning that the water coming over it tends to be warm and dirty), and the wave is shallow at most levels. A concrete wall that forms the hole on surfer's right has, in particular, caused many boaters to hit their heads and shoulders when rolling. Longhorn Dam tends to be a wave of last resort for those who need a surfing fix but don't want to drive to San Marcos or deal with tubers.
Typically the left part of the wave is the bumpiest. At lower flows, you will be forced to side surf. At higher flows, the right side of the wave will crest upwards of 5 feet. Also, at higher flows, the wave becomes stickier.
When the release from Tom Miller Dam is extremely high (> 7000 cfs, particularly if any flood gates are open), the Austin Fire Chief will usually issue a boating ban that extends to the Colorado River below Longhorn Dam. Police and fire officials can (and do) levy hefty fines or even impound your boat if they catch you breaking the ban. These bans are not always well-publicized. Generally the best place to find boating ban announcements is on the Austin Homeland Security and Emergency Management web site.
A swim here is typically not dangerous but could be tiring, since the river is 200 yards wide and the wave is dead center.
For more info, see Texas Whitewater.
WARNING: Use caution when dropping into the wave from above
At higher release levels (4000 cfs, for instance), the wave is difficult or impossible to enter from downstream. Paddlers will typically wait behind one of the pillars of the dam for a surge bubble from the dam to form, then ferry out at a 20-30 degree angle in an attempt to catch the downstream edge of the bubble. The timing of this is tricky, however, and a mistimed ferry will cause the paddler to be pushed back toward shore instead of into the wave. Some paddlers have chosen to ferry out between bubbles in order to increase the odds of catching the downstream edge when a new bubble forms, but due to the unpredictable nature of the bubbles, there is a small-but-significant risk that a bubble could form underneath the paddler when using this technique. If the paddler is unlucky enough to be upstream of the boil line when the bubble forms, then the paddler will be pushed into the dam instead of into the wave. This happened to an expert whitewater kayaker in 2007. Fortunately he lived to tell about it, but he had a wild ride during which he was separated from his boat and all of his gear. Within the local paddling community, there are stories of this happening on at least two other occasions, although no details of those incidents are known. Moral of the story: wait for a bubble to form before you try to catch it.
It also goes without saying that the dam should not be run from above. Doing so is illegal and deadly.
WARNING: Shallow Water
The depth below the ledge, even at high flows, is rarely over 4 feet, and the water is much shallower as it comes across the ledge.
There is a rebar structure located 30 yards upstream of the cluster of weeds in river center. The rebar is slightly river right of center. Many fishermen frequent this area and always seem to have 5 fishing poles each. Keep an eye out for their lines. Although it's rare, do not be surprised to catch a fish against your boat as it is hauled up to the bridge above.