Colorado

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.

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