IV-141 

 SECTION 5. DELIBERATE MODIFICATION OF THE ESTUARINE ZONE 



Deliberate modification programs are developed to intensify and 

 support major uses. In the past many of these programs resulted in 

 use damages far beyond the intended benefits, but the trends in 

 present practice include attempts to predict unsought consequences. 

 The overall impact of any modification scheme depends on the type 

 and extent of the project. 



The most common forms of modification are channel dredging for main- 

 tenance of navigation; construction of barriers to reduce damage from 

 storm waves and tsunamis; the construction of dikes, jetties, and 

 groins for navigation, storm protection, erosion control, and land 

 reclamation purposes; wetland filling through dredging spoil disposal, 

 land fill operations, and solid waste disposal; regulation of fresh 

 water inflow for upstream water use or flood protection; and the con- 

 struction of highway fills, causeways, bridges for land transporta- 

 tion. These modification activities may occur singly or in combina- 

 tion, but in general the result is the same. The estuarine zone form, 

 structure, shape, salinity, and water movement patterns are affected 

 to some degree. 



The greatest percentage of deliberate modification of the estuarine 

 zone is for the protection and maintenance of navigation. Almost 

 every harbor area in the United States requires some form of dredging 



