The Rapp Creek in Tinicum Township has an Exceptional Value rating, the highest rating a stream can get in the state of Pennsylvania. On April 25, in honor of Earth Day, members and friends of the Tinicum Conservancy will conduct water quality testing along the Rapp Creek on a private conserved property. They will also investigate the presence of aquatic organisms that are a sign of stream health. The participants will continue on with a walk along Bunker Hill Road, a scenic road paralleling the stream. Walk leaders will discuss the importance to the Conservancy of protecting properties along such a valuable stream and ways in which landowners can properly steward their critical resources.