Southwest Washington Coastal Erosion Project
For the past 80 years, government agencies such as the Army Corps of Engineers have been under the gun to solve the problems of:
disappearing navigation channels and
flooding on the Washington/Oregon coastline
Federal money has been running dry to solve these costly problems which has resulted in a new approach to minimize the inevitable yearly damages more efficiently. A comprehensive study of the beach's processes began four years ago in hopes of eventually being able to prevent future damages rather than spending millions of dollars every year on temporary solutions. A prevention method calls for understanding the great number of different natural processes and man-made constructions that affect the manner in which the coastline is continually shaped.
Most of the problems on Washington's coasts stem from the sand that lines its beaches. The studies from this project will provide a reliable sediment budget that will predict:
how/where the sediment will come from
where it will be banked
when it can be spent or used (often sand is physically moved to an eroded area)
how much can be spent, who will spend it and authorize it
The major area being studied is the Columbia River littoral cell which is itself divided into many subcells. It is generally agreed that the Columbia River provides most of the sands to the southwest Washington beaches, with the Snake River contributing some sediment as well. Additional questions are raised in the study of the major cell and sub-cells:
Does the major cell affect the sub-cells or vice versa?
Are subcells completely independent of the Columbia River littoral cell?
The rivers mentioned above are currently at their lowest discharging levels of recorded history.The reason for this is most likely due to the placement of over 100 dams on the Washington Columbia River system. These low rates result in a negative double whammy for the coastline; not only are communities, state highways, and cranberry bogs being washed away from erosion, but the rivers which have been supplying/resupplying sediment to these areas no longer have a high enough discharge rate to replenish the beaches. As sand continues to disappear from these beaches to the ocean, offshore sandbars are becoming smaller and smaller as well which just adds more fuel to the fire, making the coastline even more susceptible to erosion. Data collected from past studies shows that the majority of this shoreline is 100-120 meters lower than it was 18,000 years ago.
The Army Corps of Engineers and the EPA have been monitoring and charting water changes of the waves and tides for years. Seismic and sonar scanning devices are now producing images of the sea floor to see if erosion is an anomaly or part of a cyclic process. Global Positioning Systems (GPS) are being applied to the study which has resulted in 76 benchmark control stations in the area. GPS and sonar devices have also been hooked up to wave runners which monitor beach change during times of low tide. The CLAMMER, a unique amphibious all terrain vehicle is also being used to monitor coastal change. A great number of technologies are being applied in this project to gain a better understanding of this coastline. Our particular research group specialized in applications of Ground Penetrating Radar (GPR), vibracoring, and drilling to aid in the study. It is up to the scientists involved in this project to find out what the chances that the sea will erode any particular piece of land within a specified time frame. The greatest task of the erosion study: "to develop a database of information using the latest technology that can be accessed by the most people."
SOURCES: coming soon
Web page created by Brian Thayer using Microsoft Frontpage 98