590 



understand, and quantify every one of the factors of the system being 

 modeled. In the absence of any portion of this kind of information, 

 assumptions must be made. The more complicated a system, the greater 

 the area of ignorance, the more assumptions must be made, and the 

 less confidence can be placed in the results. To date, effective mathe- 

 matical modeling activities have been applied for some of the more 

 important water quality parameters, such as dissolved oxygen, in some 

 of the simpler estuarine systems. The research need here is to overcome 

 all of the difficulties and satisfy the drawbacks just stated. Obviously, 

 this approach should be most valuable if and when perfected. 



SUMMARY 



A. Hydraulics: 



1. Develop complete understanding of the water dynamics of 

 the estuary, including details of tidal and current regimes, evalua- 

 tions of the effects of river flows, rates of water exchange, and 

 characteristics of flushing. 



2. Determine the source, activity, and fate of both conservative 

 (e.g., salt) and nonconservative (e.g., pesticides, nutrients) mate- 

 rials in the estuary. 



3. Classify estuaries according to flushing characteristics in 

 order to enhance our predictive capability for waste disposal 

 purposes. 



4. Increase our knowledge of mixing and transport processes at 

 the various interfaces and within the estuarine water mass itself. 



5. Determine the significance of ground water inputs to the 

 estuary. 



6. Develop engineering ability to use water movements, includ- 

 ing tidal action for estuarial flushing and bottom cleansing. 



B. Sedimentation: 



1. A wide range of research is required to provide an adequate 

 knowledge of how to prevent and control the effects of pollu- 

 tional benthic deposits. 



2. Develop methods for mitigating the estuarine damage due 

 to dredging activity and improve spoil disposal practices. 



3. Increase knowledge of the effects of offshore and nearshore 

 dumping. 



4. Increase knowledge of the sources and rates of sedimentation 

 and of the effects of sedimentation on the ecosystem. 



C. Structures and physical modifications : 



1. Determine the effects of structures and physical modifications 

 on the hydraulic, biological, and sedimentological characteristics 

 of the estuarine zone. 



D. Physical and mathematical modeling : 



1. Develop physical and mathematical modeling techniques to 

 the level of yielding reliable predictive capability and to deter- 

 mine optimum control strategies for estuarine management. 



2. Develop more effective and less expensive simulation 

 capability. 



Section 8. Socioeconomic Factors 



Perhaps the most important area in need of research and study is 

 that of socioeconomic factors broadly grouped under planning, eco- 



