APPENDIX A 

 EXPLANATION OF USE OF WATER-LEVEL CONTOUR CHART 



Figure A-1 contains predicted hourly water-level heights for this station 

 for July 1969. When these values are added to the chart depth for this station 

 (or near this station), the total water depth for any time will be known. 



a. To find the total water depth at or near this station during any 

 hour of July 1969, proceed as follows: 



1 . From appropriate chart determine charted depth in feet. 

 This value is the depth below datum (depth below zero 

 of Figure A-1). 



2. From Figure A-1 read the additional height due to tide 

 and discharge at the intersection of the hour and day 

 lines; interpolate between time or height lines as 

 necessary . 



3. Add values obtained in (1) and (2) above to obtain 

 correct water depth. If the value from (2) above is 

 negative (-), subtract this amount from (1). 



4. *Example: What additional heights should be added 

 to charted depth for the following times during July; 

 problems (a) through (c)? 



a. Hour 06, day 5 



b. Hour 19, day 12 



c. Hour 0930, day 21 



Solution: Find intersection of hour and day lines for 

 examples (a) and (b). Read answers (1) + 9,0 feet; 

 (2) +4.0 feet. 



*AII five lettered problems are shown on Figure A-1 by a small circle and 

 sample letter. If the same number appears more than once, it is being used 

 to indicate a time period. 



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