2007 Annual Monitoring Report (pdf 16MB) - Bolsa Chica Lowlands ...

Bolsa Chica Lowlands Restoration Monitoring2007 Annual ReportThe Bolsa Chica Monitoring Plan (USFWS, 2001b) defined beach nourishment triggers based on themonthly beach width observations at the Corps measurement sites within the study area. Theminimum permitable beach width based on two consecutive monthly measurements was stipulated tobe 15.2 m (50 ft). A second condition indicated that the 12-month rolling average beach width couldnot deviate from the long-term mean beach width (based on the period January 1980 to January 2000)by more than two standard deviations. Table 2-7 shows the beach width statistics for the three Corpsmeasurement sites within the study that were provided in the monitoring plan.Table 2-7. Beach Width Measurement Program Summary Statistics, Jan. 2007 to Dec. 2007.StationBerm Width (m)Range Mean Std. Deviation247+88 48 - 105 64.0 7.6307+88 12 - 59 33.2 7.3424+44 18 - 81 52.4 10.4Figures 2-17, 2-18, and 2-19 show the long-term rolling average berm width from October 2006 (preproject)to December 2007 at each of the three Corps measurement sites within the study area. Thetime series plots also show the minimum stipulated berm width (15.2 m), the long-term mean bermwidth, and a shaded area encompassing two standard deviations above and below the long-term meanberm width.The 12-month rolling average berm width remained above the minimum stipulated berm width(15.2 m) throughout the period at each of the sites. At 307+88 and 424+44, the 12-month rollingaverage berm width exceeded two standard deviations above the long-term mean. At no location,however, was the 12-month rolling average berm width less than two standard deviations below thelong-term mean.Figure 2-17. Twelve -Month Average Berm Width at Corps Station 247+88.Merkel & Associates, Inc. 88