special studies succeed in their primary purpose of developing existing" 

 tidal information, but they also provided a complete inventory of available 

 data which would permit of an effective appraisal of the adequacy of 

 existing records and provide the basis for planning the distribution of 

 stations for any future sj^stematic tide surveys. 



Plans for such surveys had in fact been in process of formulation 

 while the war in the Pacific was still in progress. Prior to the war the 

 general lack of facilities in this area had imposed serious obstacles to the 

 practicable development of any co-ordinated tidal programme. However, 

 it was anticipated that the many war-created installations, scattered 

 throughout the Pacific in connection with war and occupation activities, 

 could be utilized to good advantage to provide the sites, transportation, 

 and operating personnel essential for the effective prosecution of an 

 integrated tidal programme. A reconnaisance approach to such a 

 programme was initiated- by survey units of the armed forces which 

 were under instructions to obtain tide records wherever an opportunity 

 was afforded and a considerable amount of useful data from a number of 

 localities was accumulated from this source. 



Following the war, rehabilitation of tidal installations in the 

 Philippine Islands was accomplished at the earliest opportunity and 

 primary tide stations are presently being maintained at Manila, Jolo, 

 Davao, Cebu, Legaspi, and San Fernando. During 1946 tide stations 

 were established on Kwajalein and Eniwetok in the Marshall Islands, 

 on Wake, and at Hilo in the Hawaiian Islands. The first three were 

 originally installed in connection with the Bikini bomb-tests and later 

 for seismic sea-wave investigations. 



Early in 1947 the first steps in a systematic tide survey of the Pacific 

 were taken with the installation of tide stations at Koror in the Palaus, 

 Manus in the Admiraltys, Guadalcanal in the Solomons, and at Midway, 

 Johnston, and Palmyra in the Hawaiian area. In late 1947 and con- 

 tinuing through 1948 the programme was expanded by the addition of 

 stations on Okinawa, Guam. Dreger Harbour on New Guinea, Rabaul 

 on New Britain, Bougainville in the Solomons, and on Christmas Island 

 and American Samoa. Records are also being obtained from stations 

 previously established in Apia in Samoa and Truk in the Carolines. 

 Present plans call for the installation at the earliest opportunity of 

 additional stations in Japan and China. Where practicable, stations 

 are to be operated for one or more years. 



The initial tide station installations have as their general objective 

 the determination of basic tide data both for immediate local utility and 

 for planning modification and expansion of the programme to adapt it 

 to the long-period needs of the area. Continuous records for a period of 

 a j^ear will provide sufficient data for the evaluation of the harmonic 

 constants and the time, range,-4nd type characteristics for prediction and 

 tide-table purposes. Also from series of this length there can be obtained 

 tidal datum planes necessary for the vertical control and reference of 

 surveying and construction operations. 



In the Pacific Ocean area there are known to exist many combinations 

 of tidal types and characteristics of irregular extent and distribution. 

 To chart this distribution by delineating areas of similar or comparable 

 tidal characteristics with more certainty than is possible with existing 

 data is one of the principal problems of the present investigation, and one 

 that will require considerable flexibility in programme development. 



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