turbulent processes at work. Previously unanswer- 

 able questions, such as those concerning dilution 

 of pollutants, migration of larvae, or transfer of 

 sediment, could be approached rationally. 



It is not unusual for the net circulation in an 

 estuary to be hundreds of times stronger than the 

 input from its fresh water source. Detailed, three- 

 dimensional current surveys should be carried out 

 in many estuaries to gather data on current 

 patterns and variability throughout the tidal cycle, 

 including seasonal variability. We need to ascertain 

 what changes in a particular estuary will lead to 

 greater useful circulation. We need to be able to 

 avoid changes that might lead to an undesirable 

 change in circulation, such as occurred in the 

 oft-cited example of the diversion of the Santee 

 River through Charleston Harbor.' In addition to 

 field surveys, theoretical studies and careful anal- 

 ysis of the data must be given equal priority if 

 results are to be of any lasting value. 



V. THE MONITORING PROBLEM 



In a system as complex as the coastal zone 

 there is a need for continued monitoring and 

 inventorying changing enviiorrniental conditions. 

 The data are the necessary input to any study. 

 They are also required to keep track of trends, to 

 note changes, and to alert those responsible to any 

 problems arising. Those who study the coastal 

 zone require systematic data on such disparate 

 parameters as beach slope, coUform bacteria, and 

 land use patterns. 



In some cases our understanding is not suffi- 

 cient to design an efficient monitoring system. In 

 many cases we are uncertain about the variables in 

 an ecosystem— which are important and which, if 

 any, can be safely ignored, which are primary and 

 which are derivative. 



Even when we understand the system, the 

 measurement problem may not be easy. Changes 

 take place in short distances and short time 

 intervals in the estuarine environment and the 

 range of values is great. For example, open ocean 

 salinities vary in a narrow range of several parts per 

 thousand. Estuarine salinities, however, varying 

 from to over 30 parts per thousand or more. 



change throughout the tidal cycle. In deep oceanic 

 waters, salinity differences as small as 0.002 parts 

 per thousand may be significant; in estuarine 

 situations a salinity measurement having one-tenth 

 this accuracy would be sufficient. 



Detecting long-term changes of small magnitude 

 is important. For example, when the annual 

 natural variation of temperature is 30° Fahrenheit, 

 an average annual increase of 0.5° Fahrenheit 

 resulting from thermal wastes may be undetected; 

 yet this small difference may be important to the 

 estuarine biota. 



VI. THE NEED FOR BASE LINE STUDIES 



Because of the rapid development occurring in 

 the coastal zone, many scientists have a strong 

 feeling that certain areas must be set aside for 

 detailed scientific study. In a letter to the Conunis- 

 sion the National Academy of Sciences Committee 

 on Oceanography* stated the requirement to: 



Set aside unspoiled study areas for permanent 

 scientific use. Such areas will be desperately 



Figure 4. Mote Marine Laboratory, Sarasota, 

 Florida, is an excellent example of small 

 coastal zone laboratories which are needed 

 in all coastal waters to carry out a vital re- 

 search effort. 



The unanticipated effects of the diversion of the 

 Santee River ate described in the last section of Chapter 

 3. 



Letter from Dr. John C. Calhoun, Jr., Chairman, 

 Committee on Oceanography, National Academy of 

 Sciences, May 31, 1968. This largely reaffirms NASCO's 

 views contained in its report Oceanography 1966. 



III-77 



