11-65 



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 uncompensated damage where one user group precludes 

 the activities of a second unrelated user group but does not reim- 

 burse 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 discussion of economic and social values: 

 Many estuarine values are not quantifiable. While damages to a 

 commercial enterprise, sucli as commercial 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 don't swim or go boating in the Potomac River because it is 

 polluted. 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 wetland habitat remaining in the estuarine zone of the United 

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

 habitat is irreplaceable. 



