turning basins; and (3) filling of wetlands, which must be considered 

 during the location, design, construction and operation of the facility. 



Location : The ecological problems related to service bases are 

 primarily a result of the necessity to situate the facility on the 

 waterfront. With crew boats and supply boats constituting the main link 

 between offshore needs and onshore supply, sponsors desire a sheltered 

 channel or harbor allowing efficient loading and unloading. Locations at 

 the mouth of bays and estuaries will aid in the flushing and dispersion 

 of silts stirred by boat propellers and petroleum discharges from engines. 

 Channels and harbors that require little initial or maintenance dredging 

 should be considered as first choices for the locations of service 

 bases. 



Design : All possible attempts should be made to locate service 

 bases on existing waterfront property to avoid the loss of fish and 

 wildlife habitat through filling of wetlands. The need for navigable 

 channels and turning basins will cause dredging problems of turbidity 

 and sedimentation, which may lead to the smothering of clams, corals, 

 and other sessile organisms. Channels should be designed to limit the 

 amount of initial or maintenance dredging, i.e., the channel route 

 usually should be the shortest distance to the service base. However, 

 the type of substrate must also be considered. Loose, unconsolidated 

 material requires more frequent maintenance dredging. 



Construction : With the construction of a bulkhead to service 

 boats, shores are often dredged to create the berth area and to obtain 

 fill to place behind the bulkhead. Although inexpensive and quick, 

 this method alters the natural configuration of the shoreline and robs 

 areas downshore of needed sand by interrupting littoral drift. Addi- 

 tionally, solid-fill structures tend to intercept, divert, and disperse 

 water currents in directions where previously they had not gone or 

 cause them to become diffused through mixing with other currents. 

 This diversion may decrease available food supplies and change water 

 parameters, such as salinity, oxygen, etc., leading to a significantly 

 altered fish and wildlife habitat. If wetlands are filled, there will 

 be a loss of breeding/feeding grounds and generally productive areas 

 for fish and wildlife. Construction of open pile piers and floats 

 will greatly reduce the above effects. 



Operation : Regarding service-boat traffic between offshore rigs 

 and the service base, the sponsor will find it necessary to ensure that 

 accidental and illicit discharges be kept to a minimum. All boats 

 should be rigidly inspected to prevent any unnecessary oil and grease 

 from entering the water. Also, transfer of drilling mud and other 

 compounds from the marine terminal to the boat should be executed 

 according to pre-established safety procedures to reduce accidents 

 to workmen and to the environment. 



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