and parking space, and an acre per helicopter. Accessibility to road, 

 rail, and air transport is necessary for fast delivery of supplies and 

 parts. Land must be level, with a soil base capable of supporting heavy 

 loads of pipe, storage tanks, and other materials and equipment. 



Marine repair and maintenance yards may be part of either a new 

 overall service base or existing industrial marine service areas. Thus, 

 siting requirements of general application are not as easily stated as for 

 other onshore facilities related to offshore oil and gas development. 



3.4.3 Potential Sources of Disturbance 



These facilities occupy moderate size tracts of waterfront land, 

 usually in existing developed harbors where site development and road 

 access systems may involve activities that have adverse effects. Also, 

 the use of a waterfront site for a service base or marine repair and 

 maintenance yard may involve alteration of the bay bottom and immediate 

 shoreline. 



The potential for small spills of hazardous substances is related to 

 the level of activity in handling supplies and products, and transferring 

 fuels. Storm wastewater systems may require extensive reconditioning 

 of polluted stormwater before release to coastal waters. Where hazardous 

 products are stored, diked drainage may be needed to collect runoff for 

 treatment and disposal. 



When fuel is stored on the base, good practice dictates that the 

 tanks be located away from other components and be surrounded by berms 

 or dikes to contain leaks or spills. Normally, one-quarter to one-half 

 acre of land per offshore platform is required for fuel storage [7]. 



In most cases the base can rely on the local municipality for elec- 

 tricity, sewage treatment, solid waste disposal, and water. These needs 

 are not exceptional. However, reasonably large quantities of fresh water 

 are needed offshore: for example, during exploratory dnliing about 5 

 million gallons per rig is brought from shore annually, and during develop- 

 ment drilling the figure rises to 8 million gallons [7]. 



Subproject: Navigational Improvement (SP-1) 



Disturbing Activities: Dredging, spoil deposits 



Channels, berths and turning basins at service bases may have to be 

 dredged to provide adequate navigational access for boats 200 feet or 

 longer, including workboats, crewboats, tugs, and drilling rigs. The 

 minimum channel and berthing depth is 15 to 20 feet. Supply boats 

 equipped with bow thrusters (propellers set in transverse tunnels in 

 the hull near the bow to aid in maneuvering) reportedly cause scouring 

 and silting of the harbor bottom, and so necessitate redredging within a 



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