2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
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<strong>Bolsa</strong> <strong>Chica</strong> Lowlands Restoration <strong>Monitoring</strong><br />
<strong>2008</strong> <strong>Annual</strong> <strong>Report</strong><br />
y 3 /year) for the second year after the inlet was to be connected to the ocean, for a total of<br />
approximately 230,000 m 3 (300,000 y 3 ) over the first two years. The predicted flood shoal location is<br />
illustrated in Figure 2-1. Investigations were completed to assess the true rate of shoal accretion and<br />
distribution pattern of flood shoal development.<br />
Full Tidal<br />
Basin (Phase I)<br />
Modeled Shoal Area<br />
Tidal Inlet<br />
Scale 1’’= 1,800’<br />
Figure 2-1. Predicted flood shoal area (cited from M&N 1999)<br />
Methodology<br />
The rate and distribution of sand accretion in the FTB inlet has been assessed during the first two<br />
monitoring years on January 19, 2007, June 27, 2007, January 10, <strong>2008</strong>, and July 1, <strong>2008</strong>. After the<br />
January 2007 survey it became clear that a larger area needed to be surveyed to capture the extent of<br />
the shoaling, therefore all following surveys extended a considerable distance further to the north. A<br />
survey was also conducted on December 23, <strong>2008</strong> by the maintenance dredging contractor hired to<br />
remove the accumulated sand from the inlet during the <strong>2008</strong>/2009 winter season. This survey was<br />
performed by the dredging contractor’s surveyor, CLE Engineering, Inc., and was intended to<br />
document the pre-dredge bathymetric condition.<br />
The surveys were conducted from a small survey vessel with sub-meter accurate differential global<br />
positioning system (dGPS) and a survey-grade SyQuest Hydrobox ® fathometer. Land surveying was<br />
conducted using a total station to complete areas that were too shallow to conduct hydrographic<br />
surveys during the various survey intervals. The bathymetric survey area was previously presented in<br />
Figure 1-1. The methodology for the CLE survey in December <strong>2008</strong> was comparable to that<br />
completed by M&A, as described above. The December <strong>2008</strong> survey area did not cover the western<br />
Merkel & Associates, Inc. 100