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34 .2 Offshore Surveys. Offshore surveys shall be conducted by the CONTRACTOR using standard positioning and hydrographic surveying equipment and techniques. The CONTRACTOR shall utilize horizontal positioning equipment that has an accuracv of at least f3 feet. If range-range positioning system is used, shore stations must be set to ensure the accuracy of t3 feet. The location offshore control stations for the beach profiles must be approved by the COUNTY prior to the beach profile surveys. 34 .3 Survev Points. A sufficient number of points shall be taken along each line to ensure adequate description of the profile. All topographic features, and major breaks in slope, including dunes, beach berms, foreshore, and bar and trough systems, shall be identified. On smoothly sloping sections a maximum elevation difference of approximately 1 foot between adjacent points shall be used to define this section of the profile. The design berm crest and dune crest stations on the templates in the drawings shall be included. The product shall be a continuous line representing the beach/ocean bottom profile. 34 .4 Survey Tolerance. Profile lines shall be taken along the azimuth indicated in the Construction Plans. A tolerance of no more than 30 feet either side of the azimuth on offshore segments of the profile line and a tolerance of no more than 5 feet either side of the azimuth on the onshore segment of the profile line shall be allowed. Data points obtained offshore by bathymetric survey methods (i .e., fathometer) shall be taken at a spacing of not more than 20 feet. Hydrographic surveys must extend seaward of the toe of the construction template by a minimum of 1 ,000 feet or to a depth of-30 feet NGVD, whichever is further and this hydrographic survey shall overlap the seaward end of the rod survey by at least 50 feet. The rod survey shall extend minimally to the toe of the construction fill . 34 .5 Accuracy. Offshore survey elevations shall be measured to the nearest 0. 1 foot referenced to NGVD. To ensure this accuracy is maintained, if a fathometer is used, the fathometer shall be calibrated at the start of each survey day, at every tidal shift, at the beginning and end of each paper roll, and at the end of each day . Survey vessel settlement and squat must be determined at survey speeds and applied to correct the water depth measurements. Equipment and procedures must be in accordance with the methods specified in USACE Hydrographic Surveying EM 1110-2- 1003 dated October 1994 (Updated January 1 , 2002). 34.6 Tides. Average still water elevation (tides) shall be measured for offshore beach profile surveys. This is to be done independently of the tide measurement taken for the dredge depth monitoring, if necessary. Tides shall be measured by tide staff readings using a stilling well while conducting the offshore bathymetric surveys. 34 . 7 Deliverables. Deliverables to the COUNTY shall include processed survey data of date, range, station and elevation from each of the FDEP and COUNTY and intermediate profile baseline monuments in a hard copy form, a CD, or other approved mediums, in FDEP format and MapCAD electronic drawing files. TECHNICAL AND ENVIRONMENTAL SPECIFICATIONS Rev October 5 2007 TS-34