How we estimate conditions

We use live data from three USGS gauges on Barton Creek. For spots between gauges, we interpolate flow and depth using inverse distance weighting combined with historical correlation models (linear regression on 5-year daily values). Swim quality ratings based on empirical analysis of swimmable days (66% of time, median 10.6 cfs): Dry (<0.5 cfs), Trickle (0.5-3 cfs, not swimmable), Minimal (3-5 cfs, pools only), Fair (5-10 cfs, shallow spots), Good (10-20 cfs, comfortable), Excellent (20-35 cfs, deep/current), Prime (35-50 cfs, ideal), Caution (50-150 cfs, swift), Unsafe (>150 cfs, dangerous). City of Austin officially closes Barton Creek when flow at MoPac gauge exceeds 350 cfs (occurred 4 times in 5 years).