THE BLOG

Hard Edges

03/26/2013 06:33 pm ET | Updated May 26, 2013

The fate of coastal wetlands is another blatant example of hard over soft. Once massive buffers against storm incursion, wetland control disrupted the natural arrangement that increased erosion and drained the buffer zone, followed by hard edges behind which could be deposited dredge spoils, construction debris, and other unnatural material that transformed the soft soil into hard ground on which could be constructed more housing, parking lots, shopping malls, and manufacturing plants -- all uses antithetical to Nature's original intent.

Our traditional approach to potential inundation by water has been the hard edge. It represents our cultural assumption that Nature is there to serve our needs and, when necessary, to be engineered to that advantage. You see hard edges everywhere: sea walls; dikes and levees; rip-rap erosion controls; dams; canals that artificially connect water bodies for transport by ship, for hydro power, or for redirection away from alternative, seemingly more economically desirable development.

Indeed, we have created large bureaucracies -- the Army Corps of Engineers in the United States for example -- with the mission to protect us from the encroachment of water, to shield ports and harbors against storm and surge, to facilitate the most efficient marine transportation, and to otherwise manage the environment, lakes, inland waterways, and coast-wise, to human advantage as defined by the financial exigencies of the time.

The fate of coastal wetlands is another blatant example of hard over soft. Once massive buffers against storm incursion, wetlands served human needs additionally through complementary cultivation of hay for fodder for saltwater farms. But as those farms gave way to more concentrated settlement and sprawl, the marshes were first ditched to control pesky mosquitoes that annoyed suburban residents, a disruption of the natural arrangement that increased erosion and drained the buffer zone, followed thereafter by hard edges behind which could be deposited dredge spoils, construction debris, and other unnatural material that transformed the soft soil into hard ground on which could be constructed more housing, parking lots, shopping malls, and manufacturing plants -- all uses antithetical to Nature's original intent. You could describe a similar history for the destruction of coastal mangroves in other areas around the world.

Highways are hard edges. In southern New England where I once lived, the major north-south interstate highway that extends from Florida to Maine was built to follow a coastal route that created a concrete wall between the shore and the entire land mass and marine system upstream to the point that the entire natural watershed was blocked and re-directed to three cement conduits beneath the highway, not only interrupting and concentrating the natural drainage, but also the animal migration and surface water distribution that sustained the historical ecosystem resulting in all sorts of changes, disruptions, and negative environmental consequences to the region.

More modern examples of hard edge thinking also include such things as the Thames Barrier designed to protect London, England, from flooding. The structure is built across a 1,710-foot-wide stretch of the Thames, dividing the river into four 200-foot and two 100-foot navigable spans. There are also four smaller non-navigable channels between nine concrete piers and two abutments. The four large central gates are 66 feet high and weigh 3,700 tons. In January 2013 in a letter to the London Times newspaper, a former member of the Thames Barrier Project Management Team, Dr. Richard Bloore, stated that the flood barrier was not designed with increased storm and sea level rise in mind, and called for a new barrier to be looked into immediately.

Finally, the Netherlands has long used the hard-edge concept to protect the almost two-thirds of its national territory that is at or below sea level and otherwise susceptible to flooding by three major rivers, the Rhine, Meuse, and Scheldt. Before 1000 AD, the Dutch began to protect their coastal areas with earthen dikes, followed through the centuries by timber walls, followed by higher structures reinforced by crushed rock and cement, covered over by earth on which sheep continue to graze. But flood control engineering was soon augmented necessarily by the need for increased protection and the Dutch innovated radically with the construction of an enormous barrier system that closed the natural opening to the ocean and transformed the Zuiderzee into the IJsselmeer, literally from a sea to an inland lake. This was followed in the 1990s by the Delta Works, an even larger storm surge protection system that today, in the face of projected sea level rise, is nonetheless considered inadequate for the future and has sent the Dutch engineers back to the drawing board.

Hard problems, hard thinking, hard edges: Might there be another way?