Old Waterworks Napa: Once hidden behind foliage and oak trees and nearly forgotten is this 3-acre parcel of land with a century old history as a watershed dam. The reservoir was a favorite spot for picnics and family gatherings and well known to Napa residents for its peaceful splendor. Built in 1883 this beautifully hand crafted stone wall now serves as the dramatic entrance to a secluded parcel ready for development.