2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Figure 2-15. Bolsa Chica monitoring period subaerial volume changes, Oct. 2005 to Oct. 2008
Long-Term Shorezone Volume Changes (1963 to 2008): As described previously, the shorezone
encompasses the entire littoral zone from the back beach to the depth of closure. Figure 2-16 shows
the net long-term shorezone volume changes between May 1963 and October 2008 at each of the Bolsa
Chica area transects. The comparison utilizes the May 1963 and October 2008 surveys because the
shorezone volume is not subject to seasonal bias. Shorezone volume gains prevailed at each of the
seven Bolsa Chica area transects. The gains ranged from 72 m 3 /m at Transect 378+29 to 1006 m 3 /m at
Transect 318+30.
The shorezone volume gains reflect not only the influence of the Surfside/Sunset nourishment
activities, but also the ebb bar that was placed offshore of the entrance channel as part of the
restoration project. The ebb bar, which was created by placing approximately 1 million m 3 of sand
offshore, is evident in the 2007 and 2008 profiles at Transects 311+22, 318+30 and 333+30. The time
series plot in Appendix 2-D show substantial volume gains at each of these transects between 2002 and
2007.
Merkel & Associates, Inc. 128