Willapa Bay

Description

Willapa Bay is a bay located on the southwest Pacific coast of Washington state in the United States. The Long Beach Peninsula separates Willapa Bay from the greater expanse of the Pacific Ocean. With over 310 km2 of surface area Willapa Bay is the second-largest riverine estuary on the Pacific coast of the continental United States. Early settlers called the bay Shoalwater Bay and this name is found on old maps and charts of the region. Willapa Bay is fairly shallow: more than half of its surface area lies in the intertidal zone, and half of the volume of water inside it enters and leaves with every tide. The bay is an estuary formed when the Long Beach Peninsula, a long sand spit from the Columbia River to the south, partially enclosed the estuaries of several smaller rivers. It is a ria, which formed after the rise in sea level at the end of the last ice age flooded several small river valleys. The North River, Willapa River, and Naselle River provide most of the freshwater input into the bay. Other rivers that empty into Willapa Bay include the Bone River, Niawiakum River, Palix River, Cedar River and Bear River, among others.