220 



vironment is a preferable course of action both to preserve and per- 

 haps enhance the production of fish and maintain the quality of this 

 unique environmental resource. 



COMMERCIAL AND NATIONAL DEFENSE TRANSPORTATION 



CommerGidi 



An environment favorable to transportation has been one of the 

 most significant historical factors in coastal and estuarine develop- 

 ment. Settlements originated at the sites of coastal harbors and at 

 the mouths of rivers because of the accessibility of these areas to trad- 

 ing vessels. The commerce which passed through these centers en- 

 couraged further growth and development. The coastal and estuarine 

 areas also saw rapid development of air, rail, and highway systems 

 because the main demand was located there and the terrain presented 

 few obstacles. Connecting links were needed between the coastal trade 

 centers and the hinterlands, and the level land available along the 

 coasts, bays and rivers was the natural location for railroads and high- 

 ways for both engineering and economic reasons. Airports also re- 

 quire large tracts of level land, and a waterside location affords the 

 beneifits of unobstructed and unpopulated approach zones. This con- 

 centration in coastal and estuarine centers has continued as these areas 

 have maintained their growth and thereby further simulated the max- 

 imum utilization and expansion of transport facilities. 



Airborne commerce has experienced considerable growth. Some sta- 

 tistics are available to relate it to estuarine locations. Figure IV.4.14 

 gives some liistorical data on airborne import and export commerce 

 by coastal customs districts. Airport location on or near an expanse 

 of water is desirable because it affords unobstructed approaches and 

 reduces noise problems. Airports are presently located in estuarine areas 

 in Boston, New York (both Kennedy and La Guardia), Washington, 

 Norfolk, San Diego, San Francisco and Oakland. 



A further element which will almost certainl}^ affect the estuarine 

 zone is the development of new ports. For example, if the proposed 

 free port in Maine becomes a reality there will be a rapid proliferation 

 of all types of commercial transportation to service that port area and 

 to provide a network for distribution. Since major refinery operations 

 are part of the proposed plans, this development will include pipelines 

 and associated petro-chemical facilities, and other modes of land trans- 

 port. Such a free port could have far-reaching effects on the present 

 distribution of cargo tonnages at east coast ports as well as develop 

 an estuarine area which is now relatively pristine. 



Another factor which could significantly affect the trade distribu- 

 tion of all ports is the development of the super-tankers and larger dry 

 cargo vessels. These carriers require up to 60- foot channel and berthing 

 depths. This will call for an enormous dredging operation in most ports, 

 where maximum dredged channel depth now is around 40 feet. Some 

 places, like New York, have already been dredged to bedrock level, so 

 blasting would be necessary to go deeper. An alternative solution is 

 to establish offshore docking facilities for the super-ships and bring 

 their cargoes ashore through pipelines or in lighter-type ships. The 

 bottom clearance requirements of these ships are considerably smaller, 

 which would mean far less dredging for channel maintenance. How- 



