general quality of terrestrial and aquatic ecosystems. Indirectly, 

 coastal roadway systems may induce new forms of land use along the road 

 corridor which would also preempt natural habitat areas and waterways. 

 Adequate consideration of natural systems and the proper alignment and 

 design of roadways and bridges can substantially reduce major adverse 

 efiects to fish and wildlife and their habitats. 



Neglect of important biological relationships in estuarine crossings 

 has had proven adverse consequences to fish and wildlife resources. For 

 example, in 1960 the FWS reasoned that construction of a combined 

 causeway/bridge from the mainland to Sanibel Island could eliminate the 

 scallop population of Pine Island Sound, among other adverse effects. 

 Nevertheless, the bridge was completed (in 1963), and, unfortunately, the 

 scallop population was exterminated. The apparent cause was an un- 

 ■^'avorable rise in salinity in the breeding areas northwest of the 

 causeway [75]. 



4.8.1 Summary 



OCS-related industrial development in coastal regions may create a 

 demand for new and improved roadways and bridges. They are built to 

 facilitate an increase in cormiuter, raw materials, supplies, and 

 equipment traffic. In relation to secondary development induced by OCS 

 activities, new road systems may be required to service expanding 

 commercial, industrial and residential areas. While railroad construction 

 might occasionally be required, the subject is not considered separately 

 here because potential disturbances are analogous to those from highways. 



Major disturbances to fish and wildlife resources may occur when 

 roadways and bridges transect vital areas, or impinge upon floodplain 

 areas. The nearer the roadway is to water, the greater is its potential 

 for pollution and habitat alteration. In the past, the solid-fill approach 

 to building road systems in wetlands was prevalent; however, the environ- 

 mental and cost benefits of elevated roadways have begun to make them 

 widely recognized as an appropriate alternative. 



The construction of coastal road systems may also have long-term 

 adverse impacts, such as alteration of subsurface drainage patterns from 

 excavation, water circulation blockage from continuous lateral spoil 

 banks, and pollution from roadway runoff. 



4.8.2 Highway Systems 



In locating a roadway, bridge, or causway, it is necessary to consider 

 the land and its resources as a total natural system. Highway system 

 planning then aims at identifying and setting priorities for various uses 

 and amenities and concurrently assessing environmental and cultural 

 effects. All roadways in coastal areas should be located to conform 

 with existing topography and require a minimum of alteration of soils and 



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