Here we are at an erosion site along a one-mile nature trail following the bay side of the Hatfield Marine Science Center along the Yaquina Estuary in Newport, Oregon. The erosion site is being mitigated with a cobble beach (dynamic revetment) to reduce erosion. Here in Yaquina Bay high tide brings saltwater from the ocean to mix with freshwater flowing down the Yaquina River. Within an estuary, there are four habitats: open water, eelgrass beds, tideflats, and salt marshes. A fifth habitat, the uplands, is the land adjacent to the estuary.