Soft Edges

This week's post is a continuation of last week's "Hard Edges." Here Peter Neill will argue that the hard edge has failed us, evidenced by storms that overwhelm barriers and destroy coastal structures. In this episode he will give examples of some of the slowly emerging examples of soft edge engineering and will ask, "How can we turn the new circumstances brought on by sea level rise to our advantage?"


Some years ago, a museum exhibit comparing American and Norwegian maritime culture provided an understanding of how one can respond successfully to the challenges of the ocean with two very different solutions. In this case, it was boat construction, the traditional Norwegian boats made with light ribs and planks that flexed and conformed visibly to the shifts in wave and water condition. By contrast, the American boats were built plank on rigid frames and, while these vessels were no less adaptive, or even beautiful, they confronted the ocean differently, road on the wave not in, to push over or through the water rather than adapt in or to the forces in play.

The contrast may be extended to ideas of how we protect ourselves and property from storm and sea level rise.  Last week’s post addressed the concept of  “hard edges,” the use of dikes and sea walls, dams and sea gates as barriers to the ocean, a fortress concept that engineers a didactic structural response to inundation using earthen bulwarks, cement walls, and giant doors that can be closed against the marauding sea. But what if there is another way?

The obvious alternative is “soft edges,” more amorphous and flexible ways to absorb rather than divert the ocean’s powerful incursions, indeed to let the water in. This of course has been the argument made often by environmentalists when opposing the filling in of wetlands, the destruction of marshes and coastal waterways, and the eradication of mangrove forests that for centuries provided natural protection by embracing the water and its destructive power and keeping it from the higher land beyond. We have seen the failure of the hard edge way, as storms overwhelm the barriers, destroy the resorts and beachfront homes, and otherwise demonstrate the hydraulic power of the ocean twice, once on the way inland, the other as the water withdraws, doubles down on the destruction, and draws the detritus in the sea. We had only to look at the devastation at Fukishima to witness this two-part threat.

There are slowly emerging examples of soft edge response, exacerbated now by the undeniable rise in sea level in many places, the consequent frequent flooding, and the unmitigated and very expensive consequence of ever-increasing incident of more powerful storms like Superstorm Sandy in the United States. How can we turn these new circumstances to advantage?

In the Netherlands, long the most highly successful practitioners of hard edge strategy, government is now evicting farmers from polders or marshes enclosed by dykes and converted to agriculture to restore those areas as control and containment areas when the other defenses are overwhelmed. According to a recent NY Times report, the Dutch have expanded this concept to a $3 billion integrated plan to construct and connect flood controls, spillways, polders, smaller dykes, and pumping stations into a kind of engineered capillary system that can accommodate vast increases in flooding volume as a serious alternative in public investment in additional and very expense hard edge security. 

There are other examples of this evolving thinking. Andrew Cuomo, the Governor of New York State in the US, has proposed post-Sandy that coastal properties, susceptible to continuous flooding, be purchased by government, that the owners compensated and relocated, and that the land be designated for public recreation and as natural barriers to future storm events. The cost benefit analysis of the purchase and redefinition of the coastal lands compares advantageously with the financial requirements of just a single storm, not to mention the more to come, as a practical and economical allocation of taxpayer funding.  It was ironic to note that recently while a United States Congressional debate was ongoing regarding public monies to reimburse Sandy-devastated coastal dwellers and businesses through reparation payments and a subsidized national insurance scheme that enables owners to rebuild where is, and sometimes as was, that very same federal program was advertising on television to recruit new clients for more coverage in those marginal areas. It made no sense. The cancellation of that ill-advised insurance program would no doubt begin to disable coastal development substantially in the United States, a radical, and necessary policy shift. 

In other countries, private groups, supported by international NGO’s, are initiating the restoration and replanting of extensive mangrove forests in coastal areas, again for the same reason, to re-build a natural, relatively inexpensive system that has proven its effectiveness as both storm and habitat protection, a very different double down based on knowledge and experience of Nature. In Arcata, CA, the city managers have created a wastewater treatment plant that passes effluent through a primary clarifier that separates suspended solids (using a digester to transform into methane and compost for sale), passes the resultant fluids to oxidation ponds and treatment wetlands for additional settling, and then to enhancement and treatment marshes (which also serve as recreation areas), and, ultimately, as clean water into Humbolt Bay – a natural hydraulic progress that mimics the natural cycle with effective result. It is this wisdom that we must look to for instruction lest we drown in our conventional thinking. It is through this learning that we will find our way to new ideas for ocean solutions.