IV-565 



liners to barges, traverse the coastal waterways each year. Added 

 to this are many of the 1,500 Federal vessels and many nearly 

 eight million recreational vessels. All of these watercraft carry 

 people and/or cargo, and are a real or potential pollution source. 



Mining from the estuary floor causes alteration of the estuarine 

 shape and water circulation characteristics, with a secondary effect 

 being the turbidity problems associated with material removal. 

 Mining of sand and gravel from the estuarine floor are universal 

 while oyster shell dredging in any great quantity is restricted to 

 the Gulf coast. These operations remove part of the estuarine floor 

 with a concomitant destruction of habitat and life. There are also 

 great amounts of suspended and settleable solids frequently released 

 into the water, from which they are redeposited in other places. 



The water quality of estuarine areas is dependent not only on direct 

 waste sources but also on the quality of the inflowing streams and 

 runoff entering the system. Tributary influent quality is generally 

 a good index of the type and intensity of land use surroundings and 

 upstream from estuarine system and can be a major cause of ecological 

 stress within the system. The complex interactions between fresh and 

 salt water may magnify the effects of pollutants carried into the 

 tidal regime, resulting in quality anomalies completely alien to 

 either fresh or oceanic environments. 



