Water and People
Early human impacts in Tillamook Bay, Oregon
Current mitigation and adaptation projects
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How does a Levee work?
A levee is a natural or artificial barrier that blocks water from overflowing from a river or other body of water. They are used to prevent flooding from storm surges. Levees are also used to divert bodies of water to drain land for agricultural and other human use.
How does a tide gate work?
"Tide gates open and close as the result of water level differences between the downstream and the upstream sides of the gate. Because a tide gate rests against the mouth of a culvert (or against ridges, if it is placed inside the culvert), it can open only in one direction, away from the culvert. Such unidirectional movement of
the lid allows water to flow in only one direction, downstream, and prevents backflow during flood (high) tides." - Giannico & Souder**
How does a dike work?
A Dutch word that originally referred to the bank of a body of water, a dike is a wall or embankment that holds back or prevents flooding from water. Dikes have been used to hold back ocean waters and drain land for agricultural and other human use.
*Styllas, Michael & Komar, Paul. (2006). Natural processes and human impacts as the causes of sediment accumulation in Tillamook Bay, Oregon. Shore and Beach. 74. 3-15.
**Giannico, Guillermo & Souder, Jon A. (2005). Tide Gates in the Pacific Northwest Operation, Types, and
Environmental Effects. Oregon State University.