Open Water

Characterized by open water, deep channels
The few deep water areas remaining during low tide in Willapa Bay are important fish highways/Photo Courtesy of Curt Stephens
Open water refers to those areas of Willapa Bay that are continuously submerged. Water is present in the channels even at low tide, and these channels serve as a link between the ocean and tidal rivers and streams. Channel depths in Willapa Bay range from 30 to 50 feet (9 – 15 m) with maximum depths of 75 to 77 feet  (22 - 23.5 m) below mean low water. Open-water channels provide habitat for fish and a variety of invertebrate animals and aquatic plants. Many of the fish species in the estuary are confined to open water channels as the tide falls. During high tide they disperse to the flooded mudflats and lower portions of salt marshes. Channels serve as migration pathways for adult salmon, lamprey, steelhead, coastal cutthroat trout, and other fish species on their way to rivers and streams to spawn, as well as for juveniles. Many fish species that spend their adult life in the ocean spend time as juveniles in the estuary. Deeper channels and holes are preferred habitat for white sturgeon. Clams, mussels, aquatic worms, and other small organisms are found on the bottom. Rooted aquatic plants are scarce in the main channels because of water depth and strong, erosive currents but are found in backwaters.

Facts About Open Water

Channels can be 77 feet (23.5 m) deep

Channels are the fish highways of the bay

Salinity can change drastically – more fresh when tide is out allowing river water greater influence, higher when tidal waters from ocean inundate bringing more salt