Located immediately downstream from the spillway current that comes out of Barton Springs, Austin’s big, spring-fed, municipal swimming hole, Barkin’ Springs just might be regarded as a direct rebellion against its bigger neighbor, and its admission fees, lifeguards, and no-dogs policy. The visitors from all walks of life who congregate at this swimming hole seem to share one common value: their love for dogs. This canine-lover’s paradise is almost always filled with life and activity, from owners playing fetch, children sliding down the spillway, dogs chasing each other through the…