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

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Plots of tidal elevations within the FTB and LAOH over this time period between December 21, 2006
and December 31, 2008 are presented on a monthly basis for the entire data set in Appendix 2-A.
Figure 2-7 shows a tidal comparison of February 2007, six months after the inlet was connected to the
ocean in August 2006.
Figure 2-7. Example comparison of recorded tides (February 2007) at FTB with the ocean tides (LAOH).
By analyzing the tidal records for the FTB and LAOH, it is possible to determine the phase lag for low
tide drain-out from the FTB. As shown in Appendix 2-A, there is no discernable phase lag between
the high tides in the basin and those in the ocean. The lag of the low tide in the FTB compared to that
in the ocean was approximately 78 minutes on January 19, 2007, 114 minutes on January 21, 2008,
and 288 minutes by December 13, 2008.
Discussion
The preliminary engineering studies (M&N 1999) predicted a maximum tidal range of 2.286 m and a
low tide muting of 0.213 m in the FTB under the post-construction condition. The tidal monitoring
started on December 21, 2006 so there are no tidal records available for the immediate postconstruction
condition (August 26, 2006 through December 20, 2006). The recorded spring low tides
records were truncated before January 19, 2007 as described in the tide monitoring methodology. The
FTB experienced a tidal range of 2.22 m and a low tide muting of 0.30 m in January 19, 2007. The
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