Ch. 17] DEEPWATER POINT RANGE, DELAWARE RIVER 



305 



this test, yet a 9-foot navigable channel through the entire reach was 

 open at the end of the test and the bed had reached a stable condition. 



DEEPWATER POINT RANGE. DELAWARE RIVER 



A second troublesome problem is that caused by the deposition of 

 suspended silt in a tidal stream and, to a lesser extent, by the move- 

 ment of deposited silt along the bed of the stream. As an example 



c "^«. 



WILMINGTON 



J'/, : 'i* N ' a "*'** '"SSOfr"-^ -^ AK DEEPWATER POINT,/ 

 && ^-" — ~^> JP\ / RANGE STUDY- 



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SALEM V - "^ 



Fig. 4. Deepwater Point Range model study. 



of the investigation of this type problem on a hydraulic model, the 

 study of Deepwater Point Range of the Delaware River has been 

 selected. 



Deepwater Point Range (Fig. 4) is approximately 4.5 miles long 

 and 800 feet wide with a project depth of 40 feet. At the time of the 

 model study the range shoaled at an average rate of approximately 

 2,800,000 cubic yards annually, requiring almost continuous dredging 

 to maintain project depth. According to extensive studies, the heavy 

 shoaling was due to lack of parallelism between the tidal currents 

 and the navigation channel. It was expected that the remedy would 

 be found either in realigning the ship channel to conform more closely 

 to the tidal currents or in training the currents into an alignment co- 

 inciding with the existing ship channel. It was required of the model 

 used to investigate this problem that it reproduce not only the deposi- 

 tion, distribution, and movement of suspended silt, but that it also 

 take account of the changing levels and reversing currents of the tidal 

 flow (plus the contributions of any fresh-water tributaries) . 



The model used for this study reproduced that portion of the Dela- 



