Chris Devers / Flickr
The coast of Scituate, MA has been walled, but the town still faces erosion, flooding, and storm damage that is likely to get worse as sea level rises.
Last week brought a small spate of news about efforts to plan for the three feet or more of sea level rise that scientists say we can reasonably expect this century, thanks to rising water temperatures and melting ice sheets. In North Carolina, state officials’ recommendations that local governments plan and regulate development with this amount of change in mind has brought resistance from coastal communities and businesses who fear growth restrictions. The news from Texas was even more dire. A report by Rice University oceanographers recommends that the west end of Galveston Island should be abandoned and the city consolidated on higher ground behind a seawall in order to weather rising seas.
All this may have left you wondering: What about Massachusetts? The Commonwealth boasts some 1500 miles of ocean coastline and faces among the most rapid rates of sea level rise and erosion. So what are we going to do about it?
Massachusetts Office of Energy and Environmental Affairs recently released a comprehensive climate change adaptation report. The final chapter is dedicated to coastal and ocean issues, primarily sea level rise. I came away with four
major themes, which we’ll explore over the next few days.
1. Build for tomorrow, not today
When you build a road, or a house, or a wastewater treatment plant, or a _____ (fill in the blank here), you expect it to be around for a while. So why build it in an area that’s likely to flood or wash away? Massachusetts has a variety of laws, codes, executive orders (you get the idea) that discourage or outright prohibit new development in vulnerable or dangerous areas. The report recommends continuing with or strengthening those measures. But the definitions of those areas are often based on current or even historic data.
The report recommends updating maps and documents that delineate wetlands, dunes and beaches, eroding coastlines, and flood hazard zones so that they reflect not only current conditions, but future projections. Then, base decisions about where to build (or where not to, as the case may be) on those projections. The report also notes that, in cases where development will occur in flood- or erosion-prone areas, buildings should be constructed to withstand predicted storm/flood/erosion conditions and to meet a standard of ‘no adverse impact’ on surrounding properties.
2. Rebuild wisely
It seems to be an almost instinctual human response: if something we’ve built is damaged by the forces of nature, we rebuild. For those with significant financial and emotional investment in a property, it may seem like the only possible response. And, in cases where the natural disaster was a rare or one-time event, it may well be warranted. But sea level rise isn’t like that. It’s a constant, inexorable process that will only lead to greater and greater damage to structures in its path.
The report offers several recommendations for avoiding or decreasing “repetitive losses.” First and foremost, vulnerable structures that are being rebuilt or renovated should be raised, not just above current wave height (as currently required), but above projected sea level and storm surge. Rebuilds could also be subject to the updated erosion and flood hazard maps mentioned above. There’s also a recommendation to provide financial incentives, perhaps reduced insurance rates, to communities that are early adopters of climate change adaptation policies. That’s the easy part.
The hard part is this: in the long run, reducing repetitive losses means reducing the number of structures in harm’s way. The report contains two recommendations on this front. Both would warm the hearts of those who authored EPA’s recent guidelines for beating an organized retreat from rising seas. The first is to establish some variety (and they list a few possibilities) of funds for buying properties or otherwise compensating private owners for abandoning their coastal properties. The second is to establish a statewide rolling easements policy that would allow owners to develop their properties, but not take any action to hold back the sea or stop erosion. The word “rolling” refers to the fact that the zone covered by such a policy would “roll back” to match the changing coastline.
3. Armor sparingly
During the 1940′s and1950′s significant chunks of Massachusetts’ coastline were hardened, or armored, with a variety of structures intended to hold back the sea – seawalls, revetments, jetties, groins, bulkheads, and breakwaters. Over time, it became clear that these hard structures weren’t the panaceas they might seem. By disrupting the constant, natural flow of sand and sediments on, off, and between beaches and saltmarshes, they can actually exacerbate erosion problems. Thus, the construction of new coastal armoring has been severely limited – by state law – since the late 1970′s.
Still, as a comprehensive 2009 inventory made all too clear, there are a lot of homes in Massachusetts sitting behind aging – and often ailing – seawalls. The cost of repairing all those structures is estimated at more than $600 million. To actually upgrade them to meet expected sea level rise puts the price tag at more like $1 billion. So the Commonwealth faces some tough decisions about which structures to repair and which to let go. The new report says as much, and recommends a thorough cost-benefit analysis and consideration of all alternatives when deciding what to do with existing structures. It offers only one hint as to possible criteria for deciding which communities to protect, saying that densely populated urban areas – particularly low-income areas – are top candidates for structural engineering projects.
Actually, most of the section on coastal engineering focuses not on hard structures, but on so-called soft solutions, namely beach nourishment. Soft engineering gets treated as a necessary evil – made necessary by the disruptions in natural sand flow brought about by hard armoring. Recommendations focus on ensuring that the source of sand used for such projects is sustainable, not ecologically damaging.
On Monday … Protect natural coastlines.