238 



HYDROGRAPHIC MANUAL 



depth curves could be drawn, and conflicts 

 with photogrammetric surveys. A statement 

 should also be included regarding the ade- 

 quacy of development of bottom configura- 

 tion and least depths. Any significant de- 

 ficiencies shall be described. 



4. Condition of survey. — Comments should 

 be made regarding deficiencies in field work 

 procedures, sounding records, descriptive re- 

 port, or field plotting. Cases where proce- 

 dure is definitely wrong or fails to comply 

 with the Hydrographic Manual should be 

 specifically mentioned. Criticisms from the 

 verifier's report or the report on smooth 

 plotting that are found justified and should 

 be brought to the attention of the hydrog- 

 rapher should be included. Should the con- 

 dition of the survey be found to be satisfac- 

 tory, only a simple statement need be made 

 that the field plotting, records and reports 

 are adequate and conform to the requirements 

 of the Hydrographic Manual. 



5. Junctions. — Adjoining surveys shall be 

 reported by number and year, stating their 

 relative position to the present survey. The 

 junctions shall be evaluated and discussed 

 with respect to adequacy. Important dis- 

 crepancies that cannot be reconciled shall be 

 described and probable causes stated. Where 

 a butt junction must be made because of 

 differences in depths, the condition shall be 

 specifically described. 



6. Comparison with prior surveys. — The 

 results of comparisons of prior surveys with 

 the new survey shall be summarized in a 

 brief introductory paragraph. Changes in 

 the shoreline or bottom configuration and 

 depths should be described. State whether 

 they are due to natural or artificial causes 

 or to less detailed and accurate methods em- 

 ployed in the prior surveys. Differences in 

 depths caused by dredging shall be men- 

 tioned. Details shall be discussed under 

 prior survey headings. For coordinated dis- 

 cussion, these surveys should be grouped 

 according to age except when changes ap- 

 pear to be progressive and can be described 

 more conveniently by grouping together sur- 

 veys of several periods. In each discussion 

 there shall be a statement to the effect that 



the prior surveys are superseded, except that 

 the statement may be qualified because of 

 the retention of specified details. As men- 

 tioned in 6-99, it will not be necessary to 

 discuss original surveys if comprehensive 

 comparisons were made during reivew of the 

 latest prior survey. 



(a) Wire-drag surveys. — Discuss compari- 

 son with wire-drag surveys separately. This 

 item shall include contemporary wire-drag 

 surveys which have been reviewed and prior 

 wire-drag surveys which may cover the area 

 or a portion of it. Where no conflicts occur 

 between the present survey depths and the 

 effective depths of the wire-drag surveys, 

 only a simple statement need be made to 

 that effect. Conflicts occurring as a result of 

 changes in the bottom should be recognized 

 as such. However, wire-drag surveys are 

 not superseded by ordinary hydrographic 

 surveys. 



7. Comparison with chart. — The chart 

 number and print or drawing date shall be 

 placed beside this heading for ready refer- 

 ence. Discussion of the comparison shall be 

 subdivided as follows : 



(a) Hydrography. — State the origin of 

 the charted hydrography and proceed with 

 a discussion and listing of data to be con- 

 sidered specifically in subsequent chart re- 

 vision. Most of the charted data will already 

 have been considered in the comparison with 

 prior surveys. Attention need be given only 

 to charted data from chart letters, advance 

 copies of boat sheets, U.S. Coast Guard and 

 U.S. Hydrographic Office Notices to Mariners, 

 Corps of Engineers blueprints, or other 

 sources. Where charted data from sources 

 other than Bureau surveys have not been 

 adequately disproved by the present survey 

 and should be retained on the chart a spe- 

 cific recommendation to that effect should 

 be made. The discussion should be concluded 

 with a statement as to the adequacy of the 

 present survey to supersede the charted 

 hydrography. 



(b) Controlling depths. — The controlling 

 depth notes are usually based on data fur- 

 nished by the Corps of Engineers. The re- 

 sult of the comparison with notes dated prior 



