Help clean up the Estuary in Waimea Valley. Tuesday April 22, 2014 from 9am -3pm. (Tools will be provided). R.S.V.P (808) ••• •••• ext.855 or email ••••••• @waimeavalley.net What is an Estuary? An estuary is a body of water formed where freshwater from rivers and streams flows into the ocean, mixing with the seawater. Estuaries and the lands surrounding them are places of transition from land to sea, and from freshwater to saltwater. Although influenced by the tides, estuaries are protected from the full force of ocean waves, winds, and storms by the reefs, barrier islands, or fingers of land, mud, or sand that surround them.