Where in Walnut is the Creek?

On Liberty Bell Plaza in Walnut Creek, CA, the creeks that the town was built around are celebrated. They are commemorated in concrete and surrounded by advertisements, Nordstroms and Starbucks, and not an inch of the actual creeks can be seen: they are all underground, built over, too messy and polluted to show. They are nothing but something for faceless suburbia to graft their identity on to. This treatment of the creeks seems strangely similar to a dictatorship paying lipservice to freedom.

But where, indeed, is the creek? Walking down Main Street, about a hundred feet of it shows under a bridge, coming out of one tunnel into another. Climbing down the embankment (there are no stairs, obviously), I read the graffiti:
.. A spray-painted peace sign
.. "Jason is a Pussy"
.. "If you smoke pot but don't have a pipe, come here on Sunday at 2 PM"
Not much, no. But at least the "dissidents" step into the water, unlike the "dictators".