548 



analysis techniques in the estuarine zone are seriously hampered by the 

 lack of fundamental information on the physical oceanography of 

 estuaries. The data needs pertinent to this section are for actual 

 measurements of tidal, current, and stratification phenomena. 



The obtaining of physical oceanographic information requires both a 

 program of consistent routine data collection over a large geographic 

 range and intensive case studies in individual systems. 



SEDIMENTS AND SEDIMENTATION 



All water, even the tiniest trickle, picks up and bears along minute 

 particles from its bed. These particles may be invisible to the eye, but 

 they are there and they are carried along suspended until, at some 

 place where the current slows and gravity gets the upper hand, they 

 fall to the bottom of the watercourse. These particles are "sediments" 

 and the way in which they settle out is "sedimentation." 



In some areas of the estuarine zone, natural sediment transport and 

 sedimentation cause drastic changes. However, natural sedimentation 

 is generally a lon^ term process to which the ecosystem can adapt — that 

 is, if a given species cannot tolerate a natural characteristic of a given 

 environment, the species would not exist in that environment in any 

 case. A species sensitive to sediments, therefore, would not normally 

 be present in turbid waters. Generally, then, natural sedimentation 

 cannot be considered highly damaging to estuarine biota. 



Man-induced sedimentation is unfortunately another story. Denud- 

 ing an area of earth releases to the hydrologic system an exponentially 

 large amount of sediments. Eainfall washing over these bare areas 

 carries sediment loads in slugs into the surface water drainage system, 

 disturbing the ecosystem with unaccustomed turbidity. It is frequently 

 when these streams reach sea level — the estuaries — that the water's 

 momentum is slowed sufficiently to permit the sedimentation process 

 to take place. The ecosystem is disturbed not only by excess turbidity, 

 but also by an excess sedimentary covering which coats the bottom, 

 smothering many life forms and changing the basic configuration of 

 the estuary. 



Sediment loads in rivers are transient phenomena related to sudden 

 increases in flow and other climatological conditions. Understanding 

 and mastering the problems of sedimentation pollution in estuaries 

 requires a much broader data base than is now available. Much of the 

 necessary data can be obtained through consistent sediment load and 

 bottom condition monitoring throughout the estuarine zone. 



USES AND USE DAMAGES 



A body of water may be littered with floating debris, it may be turbid 

 and foul-smelling, and to all intents and purposes, dead, yet proving 

 a damage to use is very difficult. One reason for the difficulty is that 

 damage must be measured by the yardstick of the values that were 

 present when the body of water was clean. If no data from that time 

 are available, precise quantification may be impossible. 



Enforcement of the water quality standards will negate much of 

 the necessity for proving damage to use, but use damage data is, and 



