Page 855 miscellaneous 9341 



The purpose of the review is to extend this correlation into the past and more 

 broadly into the present and future, and generally to consider the survey in its broader 

 aspects insofar as its application to the charts is concerned. The survey is compared 

 with every prior survey (hydrographic, topographic, and wire-drag) made by the 

 Bureau covering the same area, and with charted data that have originated from 

 other sources. 



The aim of the review is to make the survey complete with reference to all infor- 

 mation on prior survey sheets, so that it is unnecessary for the chart compiler to 

 consult any prior surveys of the area covered, except as specifically mentioned in the 

 written review. 



The reviewer must be intimately familiar with conditions in different regions, 

 and not only with present-day standards of accuracy and methods of surveying, but 

 also with those of prior periods. 



9341. Records, Reports, and Instructions 



Before beginning the review of a hydrographic survey, the reviewer should familiar- 

 ize himself with the survey, the methods of field work used, the characteristics of the 

 area, and the preceding office work. For this purpose he should first familiarize himself 

 with the largest-scale chart of the area, and then read the following to see whether 

 they contain data or information that might affect the general treatment of the sheet: 



(a) The project instructions (see 121 and 842^). 



(6) The Descriptive Report (see section 84) . 



(c) The verifier's report (see 9339). 



(d) Special reports intimately connected with the survey (see 842Z). 



9342. Inspection of the Work of the Verifier 



The reviewer should inspect generally the various phases of the oflSce work done 

 by the verifier, checking anything important that has not previously been checked, 

 and examining critically any changes that the verifier may have made to ensure 

 that they are justified. He should call to the verifier's attention any errors or de- 

 ficiencies in the latter's work, and have the errors corrected and the deficiencies 

 supplied. Particular attention should be given to the following: 



a. Differences of depths at crossings. — The reviewer shall inspect the sheet for excessive differences 

 at crossings that have not already been noted. Any found shall be investigated with a view to 

 rectifying them and ascertaining the probable causes. (See 7771 and 842K.) 



b. Depth curves. — The sheet should be examined for omitted depth curves or unnatural convo- 

 lutions with a view to remedying them. In coastal waters and inside waters, where the bottom 

 is generally flat or regular, intermediate curves of 3, 24, and 36 feet should sometimes be inked to 

 emphasize features that would otherwise be unnoticed. In offshore coastal waters beyond the 20- 

 fathom curve the standard curves shall always be inked (see table 27) . Any nonstandard curves 

 shall be inked in brown. (See also 7762 and 7763.) 



c. Junctions. — The reviewer should examine individually the various junctions with contemporary 

 surveys and see that the soundings have been correctly transferred and verified, depth curves adjusted 

 and inked, and proper junction notes made on the respective sheets. 



Surveys that are not contemporary but with which the project instructions specify that a junc- 

 tion shall be made, are to be similarly treated. Where the instructions require a junction with sur- 

 veys of the United States Corps of Engineers, such junctions are to be examined for adequacy (see 

 9348D), but the soundings should not be transferred. 



d. Adjustments of topographic and hydrographic data. — Conflicts between contemporary topo- 

 graphic and hydrographic surveys should, of course, be adjusted by the field parties before the sur- 



