EVEREST June, 2013 - California Department of Boating and ...

Orange County Coastal Regional Sediment Management Plan
3.3 Construction Solutions
Various capital improvement projects are considered within the Plan as means to physically
address beaches that have a known need for either nourishment or retention. These capital
improvements often take the form of maintenance activities, construction projects, or purchases
of major equipment. Short descriptions of typical construction projects and methods are
presented in the following along with discussion of key coastal RSM issues associated with
each.
3.3.1 Bypassing and Backpassing
Bypassing within the context of this report includes actually bypassing of sediment around a
dam or other obstruction as well as trucking (or transporting by other means) sediment to
downstream or downcoast locations. Bypassing can take place around dams and sediment
traps at upland sediment sources or around harbors and sediment traps within coastal littoral
systems.
Dam bypassing entails dredging sediment from an upstream location and depositing that
sediment either immediately downstream or farther downstream either within the river or on the
banks of a river. An excellent example of a proposed fluvial bypassing demonstration is the
ongoing Prado Basin Sediment Management Demonstration Project proposed by the Orange
County Water District and USACE.
Trucking, rail, conveyor belt, or other transport of sand from an upstream location directly to the
beach would loosely be considered a form of bypassing in that the material is bypassing the
obstruction and being deposited where it naturally would have gone, had the obstruction not
been present.
Coastal bypassing within Orange County occurs as a result of maintenance dredging in the
Bolsa Chica Ecological Reserve, the Huntington Beach Wetlands, Santa Ana River Estuary,
Newport Harbor entrance channel, and the Dana Point outer harbor. All of these efforts result in
placement of dredged sand downcoast as beach nourishment.
Backpassing is similar to bypassing in that sediment is dredged from one coastal littoral source
and placed in another. With backpassing however, the material is placed upcoast instead of
downcoast. Nearby examples where backpassing occurs are at the Balboa Peninsula and from
West Beach to East Beach in Seal Beach.
3.3.2 Beach Nourishment
As discussed in Section 3.1 of this report, beach nourishment, also known as beach
replenishment or beach fill, is the placement of mostly sand sized sediment on the upper profile
of the beach, sometimes extending into the tidal zone, for purposes of widening the profile. The
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