36 



water supply are the major uses restricted by pollution from liquid 

 waste discharges. 



Some kinds of commercial fishing require the use of trawls or the 

 setting of traps or nets that must be left for some time. The use of 

 such devices restricts other uses while the devices are in place, but 

 there is no permanent appropriation of estuarine waters or space. 

 The major conflict is with recreation in that recreational boating must 

 be excluded from areas where fishing gear is near the surface. 



Where there is conflict, the scene is set for trade-off, i.e., a willing 

 substitution of one activity for another. The scene is equally set for un- 

 compensated damage where one user group precludes the activities of a 

 second unrelated user group but does not reimburse them for damage. 

 Actual documented examples of use damages are difficult to find. One 

 major reason is the basic fact that has permeated much of the discus- 

 sion of economic and social values: many estuarine values are not 

 quantifiable. While damages to a commercial enterprise, sucJh as com- 

 mercial fishing, can be quantified in terms of the economic loss, the 

 essentially intangible values of recreation and estuarine habitat are 

 difficult to measure. 



Recreational loss would have to be measured in terms of how many 

 people donH swim or go boating in the Potomac River because it is pol- 

 luted. It is far easier to find out how many people do go there even if it 

 is polluted ; even these values are hard to find. 



The value of estuarine habitat is just as difficult to establish. There 

 are now about 5.5 million acres of important estuarine marsh and wet- 

 land habitat remaining in the estuarine zone of the United States. 

 Perhaps each acre is not valuable by itself, but the total habitat is 

 irreplaceable. 



Use damage is not a necessary feature of civilization in the estuarine 

 zone, but use conflicts will continue to exist as more and more demands 

 are made on the natural environment. The ability of any management 

 authority to prevent use damage and to resolve use conflicts depends 

 not only upon its institutional composition and legal authority, but 

 also upon the social, economic, and biophysical characteristics of the 

 estuarine management unit within which its authority is exercised. 



The analyses of social and economic values of the estuarine zone 

 examined concurrently with the similar analyses of use conflicts, pol- 

 lutional effects, and use damages form the basis for resolving use con- 

 flicts through the application of technical knowledge, i.e., technical 

 management. 



The primary objective of technical management is to accommodate 

 the needed and desired uses of any estuarine management unit within 

 that system without overall damage to the biophysical environment. 

 The ability to achieve this objective depends on the boundaries of the 

 management unit and upon the means available for resolving both 

 prohibitive use conflicts and restrictive use conflicts. 



The impact of the social and economic requirements of civilization 

 on the natural estuarine environment is the technical problem with 

 which management must deal, and effective control of this impact can 

 be maintained only if both the major sources of damage and the geo- 

 graphic range of their influence are subject to unified control. 



An estuarine management unit, therefore, should consist not only of 

 the estuarine waters, bottoms, and associated marshlands ; but it should 



