Coastal Benefits and Impacts of Dismantling Matilija Dam

Bailard, James A.; ,

Coastal Benefits and Impacts of Dismantling Matilija Dam

by James A. Bailard, (M.ASCE), Scour Systems, Inc., 1150 Bailard Avenue, Carpinteria, CA 93013, United States,

Document Type: Proceeding Paper

Part of: Sand Rights '99: Bringing Back the Beaches

Abstract:

A numerical shoreline evolution model was used to examine the shoreline changes associated with the release of 2.3 million cubic meters of beach quality sediment from behind Matilija Dam. Three alternatives were considered for delivering the sediment to the mouth of the Ventura River: pipeline pumping, trucking, and fluvial transport. The latter involves gradually notching the dam. Each alternative was found to produce a buildup of sand on Pierpoint Beach, but with differing rates of accretion and downcoast transport. None of the alternatives produced significant accretion at Surfers Point, due to the high rate of potential longshore transport in that area. Rates of sand influx into Ventura Harbor were found to increase sharply in the short-term, particularly for the pumping alternative. The trucking and fluvial transport alternatives were found to be the least impacting, particularly if carried out over a long period of time. All the alternatives were found to produce significant long-term benefits to the coastline.

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