IV-127 



Water-borne transportation in the estuaries is not a completely 

 free gift. In all cases a large investment is required to sup- 

 port and sustain this activity. Adequate channels must be pro- 

 vided to carry the ship traffic. In almost all estuaries this 

 involves maintenance dredging to provide sufficient water depth 

 to float deep draft vessels (Figure IV. 2. 15). These channels 

 must be marked with navigation aids to prevent the ships from 

 inadvertently straying into shallow water. Terminal facilities 

 are necessary for loading, unloading, and storing cargo. There 

 must also by shipyards with all the equipment and facilities 

 necessary to repair, maintain, and fuel the large ships (Figure 

 IV. 2. 16). 



Besides the physical facilities needed, there are certain envi- 

 ronmental considerations. Already mentioned is sufficient water 

 depth to keep the ships afloat. Since dock facilities and berth- 

 ing space are expensive and cannot be monopolized for long per- 

 iods of time by single ships, there must be safe anchorage areas 

 where ships can await their turn at the piers. These anchorage 

 areas also provide temporary safety during stormy weather and 

 must, therefore, be sheltered from the direct force of the wind 

 and waves. The whole concept of a harbor is a port of safety 

 out of harm's way. 



