One way to check on Barton Creek Greenbelt water levels and swimming holes is to look at stream flow data from the U.S. Geological Survey (USGS). There are stream flow gauges on Barton Creek at Highway 71, Lost Creek Blvd., Loop 360 and just above and below Barton Springs.
It’s especially interesting to look at these sites during a heavy rain.
Here’s a quick guide to conditions:
If there is water flow at Loop 360 you can count on the creek being pretty full from end to end, as there’s a high spot at the bend in the creek just downstream from the Mopac bridge.
If there’s flow at Lost Creek but not 360 then the upper swimming holes may or may not be flowing, but the dam at the Hill of Life is probably OK.