Mass Destruction of Ecosystems to Accommodate the Automobile
Mitigation, to the dismay of some, has become publicly synonymous with notions of preservation and conservation. Mitigation is neither the ‘preservation’ nor is it the ‘conservation’ of habitat. Mitigation is the creation of new habitat, or the guarding of an existing habitat to "make up" for the destruction of similar habitat somewhere else. It was the infamous environmental buzz word of the nineties, notorious for its criticism and praise by developers. Criticism because mitigation delays and obstructs their progress, and praise by those who take advantage of loopholes within the guidelines. All the while ecologists are accepting the mitigations like ill tasting medicine in the hope that it will work, after all it is at least something. It has gone so far that some, working within the fields of restoration ecology and other areas have misgivings about sharing the knowledge acquired through their efforts in regards to their efficacy in restoring or moving habitat set to be destroyed. They feel that their successes in mitigation will simply encourage the destruction of more crucial habitat. It is a bittersweet victory , for them mitigation is definitely not conservation.
With this clarification of mitigation in mind the development of transportation technologies is faced with a dilemma. A way to transport people, goods and services along the surface of the earth in a manner unobtrusive to the flora ,fauna and natural environment which surround us. If going through, or around the habitat is unacceptable, what about going above or below it ? Tunnels and bridges have been employed as methods of conveyance through areas where building roads was not feasible for many thousands of years. Subway systems in cities such as New York, Moscow ( the world’s busiest at 8 million persons per day) and Barcelona as well as above ground light rail in cities such as Seattle and San Francisco have made extensive use of underground passageways and bridges. Feats that would have been technologically impossible even 50 years ago are now common, such as the BART crossing under the San Francisco Bay or the extensive bridge systems in the Florida Everglades.
The technology exists, albeit at what is sometimes great cost. The proportions necessary to create a tunnel or bridge to accommodate the traffic flow from south Orange county north into Los Angeles would be fantastic, but possible. But bridge and tunnel systems do offer some alternatives to the mitigation practices of today. Not entirely eliminating the need to mitigate for the effects of the transportation systems, but hopefully allowing the system to pass through the habitat not completely inhibiting the integrity or the function of the ecosystem.
Bridges introduce many interesting options for elevating a roadway above sensitive habitat. Bridges seemingly are best adapted for sensitive aquatic habitats. For example, in place of...