CHAPTER Il, SECTION 1 original survey made in 1953 by Holmes & Narver, Inc. Operation REDWING necessitated the establishment of a new control due to the effects of the previous test operation. It was necessary to establish new second order stations on Charlie, Dog, and George and also to replace triangulation station Coca in the lagoon. These new stations were tied into the remaining portion of the primary network of second ordersta- tions. Figure 2-12 shows the Horizontal Control Network for Bikini Atoll and Table 2-1 lists the Horizontal Control Stations. VERTICAL CONTROL. After Operation CASTLE, it was evident that some absolute method for determining the data for all sites was needed. Two portable automatic recording tide gages were purchased, Figure 2-7. Station Coca - 2 (Left) Old Station Coca (Right) one each for use at Bikini and Eniwetok Atolls. These tide gages were set up at all major operational sites and a datum wasestablished for the construction of scientific structures. TOPOGRAPHIC MAPPING. Topographic maps of sites Charlie, Dog, Easy, Fox, and George in Bikini Atoll and Yvonne in Eniwetok Atoll were required by the Users. High tide line surveys of many islands were also provided. HYDROGRAPHY. Various hydrographic surveys were accomplished during Operation REDWING. As the need for hydrographic surveys has increased with each Operation, a Raytheon portable re- cording echo depth sounder was purchased. To date it has been used for checking depth at the deep water pier, sounding the various craters, locating channels, and charting the la- goon from the south edge of Fred to the north end of Elmer for the possible location of dredge material. This instrument has eliminated the slow and uneconomical lead line sounding method formerly used. CONSTRUCTION LAYOUT. Layout of all scientific structures and stations constituted a large part of Survey Department requirements. This consisted of preliminary staking for clearing and rough grading, followed by accurate layout of the particular station or facility. Normal survey procedures were used for most of the scientific construction. Due to the isolated locations of a few stations, such as the Man-Made Islands and Stations 130.01 and 131.04, special survey methods had to be used. Pipeline Stations 1811, 1812, and 1813 located at Yvonne were long single-pipe arrays which presented little difficulty in alignment. Figure 2-8. Station Oscar Normal tight survey procedures were used in all cases with a curvature correction applied in accordance with Home Office drawings. FabriPage 2-9