55. SELECTION OF A PUN OF PROTECTION 



As indicated in paragraph 53* preliminary study indicated 

 that tidal flood barriers offered more effective and economically 

 justifiable protection for Narragansett Bay than individual local 

 protective structiires. Analysis of the four barrier sites selected 

 for complete study on the basis of preliminary investigations 

 serves to eliminate all potential sites between the confluence of 

 the Blackstone and Providence Rivers and the Lower Bay. As indi- 

 cated in paragraph 51i and again in paragraphs SUb (2) and (3), 

 build-up, which increased from a negligible amount at the head 

 of the Providence River to a maximum of between 2 and 3 feet 

 in the Middle Bay, after which it decreases to about 0.5 foot at 

 Newport, would cause a seriously damaging increase in the tidal 

 flood levels below the barrier sites, either for the Fields 

 Point location or for the considered Middle Bay location. Similar 

 problems would clearly obtain for any proposed inteimediate points. 

 In addition, as noted in paragraph 5U the Fields Point site, or 

 any other below the confluence of the Providence and Blackstone 

 Rivers, would radically increase construction costs by reason of 

 the very heavy pumping facilities necessary to discharge the flood 

 flows of the Blackstone River. 



In addition to these considerations, however, a barrier located 

 in the Providence area, and designed to provide local protection 

 to the city, will eliminate about 35 percent of damages incurred 

 in the entire Narragansett Bay area, leaving virtually the whole 

 bay, including extensive Naval installations, with no protection. 

 Conversely, Lower Bay barriers, although they will overwhelmingly 

 reduce damages throughout the majority of the shoreline, will 

 not provide satisfactory protection for Providence and the Upper 

 Bay area inasmuch as the 25-mile fetch up the Bay will allow 

 hurricane winds to generate damaging storm waves with high levels 

 at the head of the bay. In view of this, it is considered that 

 both barriers are necessary to provide a satisfactory plan for 

 the over-all protection of Narragansett Bay against hurricane 

 tidal flooding. Consideration was therefore given to specific 

 locations for the Fox Point and Lower Bay barriers. 



a. Fox Point barrier . In the 0.8 mile of the Providence 

 River between the head of navigation and the confluence of the 

 Providence and Blackstone Rivers, there wo;ild be no significant 

 difference in pumping requirements, construction costs, or 

 build-up below the barrier. The Fox Point site, therefore, was 

 selected as being farthest downstream, and hence, protecting 

 the greatest area of the center of Providence. A barrter at 



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