How do you illuminate a spectacular gateway bridge without disturbing the nests of loggerhead sea turtles nearby or altering the flight pattern of migratory birds flying close to the bridge? When the South Carolina Department of Transportation (SCDOT) faced this challenge on the new Ravenel Bridge spanning the Cooper and Wando Rivers and connecting Charleston with the town of Mt. Pleasant, the Department signed an agreement with the US Fish and Wildlife Service to use 250-watt bulbs instead of the originally planned 1,000-watt bulbs to light up the bridge's two diamond-shaped towers and its 128 supporting cables. In talks with local government, SCDOT also agreed to turn off the aesthetic lighting from 10 pm to 6 am during the loggerheads' nesting season (May through October). For the rest of the year, lights would go out at midnight except for a flashing light at the top of the bridge and safety lighting along the road bed. Proposed overhead sign-lighting was abandoned in favor of highly reflective sheeting. Thanks to SCDOT's flexibility, loggerheads won't leave their nests prematurely, migratory birds won't fly towards the bridge lights, and local taxpayers will ultimately benefit from lower power costs.
--Aug 21, 2006
|The gateway bridge|