IV-439 



been saltwater intrusion into the outer marsh system (in the absence 

 of the freshwater inflow from inland sources now prevented by the 

 highway), with the subsequent results of soil alteration and 

 eventual alteration of the marsh vegetation (IV-6-3). 



Such alterations may permanently change ecosystems and therefore 

 exclude the estuarine uses which depend on them. Commercial fishing 

 and sports fishing are particularly impacted by such changes. 



Shoreline Development 



Estuarine snorelines are extremely valuable for both commercial and 

 residential development. The shorelines of large cities are 

 extensively built up, primarily for navigation access and other 

 commercial development, but with considerable areas of shoreline 

 drives and residential developments. Nearly all of such kinds of 

 development extend up to, and sometimes beyond, the natural shore- 

 line and terminate in bulkheads, docks, or other permanent structures, 



The individual impact of such development is probably minimal except 

 in extremely confined areas, but the total effect of the shoreline 

 development of a large city can be to drastically and irretrievably 

 change the natural environment, even to the extent of damaging the 

 uses for which the changes were made. 



Reduced currents and changes in water circulation may result in 

 increasing rates of dedimentation and added expense for channel 

 maintenance. 



