VI-147 



curtailing sediment deposition and more effective and beneficial 

 means of sediment removal and disposal. We need to know what 

 levels of sedimentation rates are tolerated by organisms, and 

 what levels are damaging to desirable organisms. Since organisms 

 are affected differentially by sedimentation processes, rates 

 of change would have to be studied specifically for key individual 

 species. Another source of sedimentation is the flocculation 

 of colloidal suspensions of materials entering sea water with 

 resulting deposition at the salt water interface. In order to 

 avoid the problems of silting and deposition of sediments within 

 lagoons or in channels, we must know more about rates of filling, 

 mechanisms of clay and silt deposition, and concentration of 

 organic debris and pollutants in sediments and in marsh vegetation. 



STRUCTURES AND PHYSICAL MODIFICATIONS 



It is well known that structures and physical modifications within 

 the estuary may change the hydraulic, biological, sedimentological , 

 and many of the other characteristics of the area. While it is 

 desirable to reduce our activities of this nature, it is probable 

 that pressures of population and economics will force continuing 

 estuarine construction. As construction takes place within 

 coastal areas, many changes will occur in the estuaries. The 

 effects of these changes should he known before constructing 

 industrial plants, homes, highways, or airports; dredging canals 



