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<br />Sylvan Beach Shoreline Protection and Nourishment Project <br />Technical Memorandum of Survey Update and Cost Estimate Summary <br /> <br />2.0 SA THYMETRIC SURVEY <br /> <br />A hydrographic and shoreline survey was conducted on April 15, 2008 by Landtech Consultants <br />to supplement the existing bathymetric survey performed in 2003. The purpose of this activity <br />was to obtain a better understanding of the shoreline and adjacent bay bottom. The scope of <br />work included: <br /> <br />· Hydrographic survey of approximately 1,700 feet of shoreline; and <br /> <br />· Collect survey transect data at every 100 feet along the project shoreline which equates <br />to approximately 17 transects. Each transect extends 50 feet landward of the shoreline <br />to 450 feet from the shoreline. <br /> <br />Bathymetric data was collected using a single-beam dual-frequency echosounder. The US <br />Army Corps of Engineers' (USACE) standards for "Hydrographic Surveying" were followed <br />when applicable. The survey meets "Other General Surveys & Studies (Coastal Engineering <br />Surveys)" specifications according to USACE Manual No. 1110-2-1003, dated April 1, 2004. <br />Quality control and quality assurance procedures as presented in the USACE Manual were <br />followed where applicable. <br /> <br />North American Vertical Datum (NAVD) 88, State Plane Texas South Central (FIPS 4204) Zone, <br />and North American Datum (NAD) 83, in US feet were used for this survey. Survey control was <br />recovered, set and checked with existing control in the area. Sea level datum were referenced <br />to the nearest tidal gauge located at Morgans Point (see Figure 1 below). Static GPS <br />processing techniques were used to check the horizontal and vertical coordinates at the GPS- <br />RTK base location. <br /> <br />Overall, the survey data showed a slight increase in depth throughout the project location when <br />compared to the previous survey. The survey deliverables have been included as Appendix A <br />to this report. <br /> <br />Figure 1: Tide Reference Chart <br /> <br />Morgans Point 87706131 <br /> <br /> <br /> MHHW <br /> .., <br /> MSL CD <br /> ~ <br />,...L MLLW 18 <br />0 g: .,; <br />0 <br /> ~ .,; <br /> .,; <br /> <br />;~ <br />Naiarnith Marin. Sarvioes l' <br />e_ FJoor eurveyll'l1iJ <br /> <br />2-1 <br /> <br />Last Revised: OS/23/08 <br />