211 



efficient integrated survey program. Supple- 

 mental activities could be conducted con- 

 currently to obtain limited biological data, 

 sediment samples, and shallow cores to help 

 illuminate resource potentials. 



The Coast and Geodetic Survey has pro- 

 posed a 70 ship-year program to provide the 

 initial topographic and geophysical maps of 

 tiie U.S. continental shelves and adjacent 

 slopes to a depth of 2,500 meters, compiled at 

 a scale of 1 : 250,000. This scale will satisfy 

 the needs of the Federal agencies charged 

 with management of marine resources and of 

 industries engaged in resource development. 

 It also will portray adequately the essential 

 descriptive information required by the 

 scientific community. 



A considerable volume of bathymetric and 

 geophysical data already exists for the con- 

 tinental shelf. Unfortunately, much of the 

 data having measurement and position accu- 

 racies that meet mapping standards cannot 

 be made public, because they are either pro- 

 prietary or classified for national security 

 reasons. Every effort should be made to ob- 

 tain these data and thus avoid unnecessary 

 resurveys. New surveys should be restricted 

 to areas which are economically and scien- 

 tifically important and have not been pre- 

 viously surveyed with the requisite density 

 and precision. 



The Commission recommends that the 

 National Oceanic and Atmospheric 

 Agency (ESSA) undertake the systematic 

 mapping of the bathymetry and geo- 

 physics of IT.S. nearshore waters and 

 continental shelves and slopes to a depth 

 of 2,500 meters. The program should be 

 funded at a level to provide 1 : 250,000 scale 

 continental shelf and slope maps of 

 bathymetry, magnetics, gravity, and sedi- 

 ment depth and type within 10 years. 

 Every effort should be made to declassify 



existing data which are of mapping accu- 

 racy and thereby avoid the need for 

 resurveys* 



Nautical Charts 



Nautical charts have not always been avail- 

 able. In the earliest days of this coimtry, 

 mariners were left to learn from the ship- 

 wrecks of others. To correct this condition 

 and to advance the economic potential of a 

 young country, an early Congress established 

 and funded a Federal program of nautical 

 charting. This program retains its impor- 

 tance today, because charting is not a job 

 that can be done once and then forgotten. Not 

 only must manmade and natural changes be 

 continually resurveyed and recharted, but 

 chart format, level of detail, and scale of por- 

 trayal must be modified constantly to reflect 

 changing user needs in the light of changing 

 technology. Any survey made more than 50 

 years ago was done by leadline or sounding 

 wire; it has been only during the last 10 

 years that surveys have been required to meet 

 the particular needs of submersibles and 

 deep-draft supertankers. 



Nautical charting surveys must be ex- 

 panded substantially if present and future 

 needs for accurate and up-to-date charts are 

 to be satisfied. Only about 10 per cent of the 

 total requirement for nautical charting 

 bathymetry can come from the continental 

 shelf and slope mapping program described 

 in the previous sections. Requirements, priori- 

 ties, and procedures for the two programs are 

 sufficiently different that in large part they 

 must be carried out separately. 



ESSA, which is responsible for domestic 

 civil nautical charting, has proposed that 

 resurs'eys be performed on a 50-year cycle in 

 80 per cent of the areas for which charts are 

 maintained and on a 5-, 10-, or 25-year cycle 



