Providence to 32 parts per thousand at Be avert ail Point. Due 

 to the reduction in tidal range that would result from the 

 barriers, the salinity within the hay would be reduced by about 

 1 to 3 parts per thousand. 



(5) Pollution and fisheiies . Effects of the Lower Bay 

 barriers on pollution and fisheries are undetermined. Their 

 evaluation is a difficult problem involving intimate knowledge 



of the present physical, chemical and biological makeup and 

 balance in the bay and the new balance resulting from the barriers. 

 Analytical studies are in progress by the U. S, Public Health 

 Service and U. S. Fish and Wildlife Service. In conjunction with 

 these studies, additional tests are in progress using the model 

 at the Waterw^s Experiment Station, both with and without the 

 barriers, of the salinity regimen and distribution, flushing 

 action and dilution of wastes, sedimentation patterns and rates, 

 and temperature range and distribution in Narragansett Bay. 



(6) Beach erosion . Detailed information concerning 

 beach erosion in the area above the Lower Bay barriers of 

 Narragansett Bay is not available. It is known, however, that 

 beach erosion problems exist along sections of the shore in 

 V/arwick and Jamestown and possibly in other areas. The Lower 

 Bay barriers are not expected to have any harmful effects as far 

 as beach erosion is concerned. On the contrary, they would have 

 definite beneficial effects by reducing wave attack behind the 

 barriers. 



6U. ADDITIONAL STUDIES OF LOWER BAY BARRIERS 



The combination of structures which con^jrise the Lower Bay- 

 barrier plan is not one that can be built immediately. The scope 

 of the problem is such that further expensive studies and research 

 investigations are required. These studies inclvide the following: 



a. Design flood . 



(1) Determination of the maximum probable hurricane as 

 a check on the selected design wind field. 



(2) More complete investigations of tidal surges for 

 effects of three different types of storms. 



(a) the fast moving storm, vftiich gives a high 

 sharp crest 



5U 



