CAUSEWAYS:
Causeways are bridges in effect; the roadway is supported either
on a long earth fill over a series of culverts or on a timber or
concrete slab resting on piling. Earthen causeways are inappropriate
in tidal areas and marshes where the ebb of water is critical
to the quality of aquatic habitat. Causeways make up most of the
Chesapeake Bay Bridge-Tunnel and are used to carry roadways across
Lake Pontchartrain and to connect the Florida Keys. The structures
provide a beneficial reef effect for fish populations; adversely,
they impose a narrowing of navigation channels. I do prefer pilings
to earthen causeways.
