By John Geluardi
If you’re ever tired of the concrete, steel and glass that dominates San Francisco’s downtown, take in a refreshing, inner-city nature hike to the Powell Street BART Station. That’s right, you go all the way down to the train platform, stroll up to the western end and cock an ear up one of the two tunnels for the sound of gurgling freshness.
What you'll hear is the rushing of an underground creek that intersects with the BART line at Powell Street. Thousands of gallons of fresh spring water pass through a special culvert that prevents the station from being flooded.