Amendment seeks to address possible impacts on estuaries
The Portsmouth Herald
April 25, 2010
Concerns about rising sea levels are not new or novel. It was more than 11,000 years ago that scientists cited as the last time ocean boundaries changed dramatically on the Seacoast.
According to a 2001 report on coastal flooding and rising sea levels by University of New Hampshire researchers, some 12,000 years ago the coastline reached as far inland as Barrington while a millennium later, the coastline extended to the Isles of Shoals — and then began to recede to its current configuration.
The Wisconsin glaciation that impacted the Gulf of Maine thousands of years ago has been updated to modern worries about global climate change and rising sea levels — especially with rapid melting of Arctic ice packs. An amendment by Rep. Carol Shea-Porter, D-N.H., that was part of the Clean Estuaries Act which passed the House earlier this month, put sea level change front and center. Shea-Porter said the measure ensures the comprehensive conservation and management plans within the National Estuary Program would address impacts of potential sea level change.
"My amendment will further protect our coastal communities by ensuring that sea level change is taken into account when the comprehensive conservation and management plans are constructed," said Shea-Porter in a speech on the House floor.
Robert C. Moller, Shea-Porter's legislative director, said she "has talked to people all over the state and she's been told that the impacts of sea level could be dramatic for New Hampshire." Moller said a rising sea level could worsen future storm surges and flooding could make sensitive estuary habitats such as Great Bay and Hampton harbor even more vulnerable.
"Sea level change has certainly been something local groups in New Hampshire are concerned about," he said.
Those groups include the New Hampshire Coastal Program, Great Bay National Estuarine Research Reserve and the Piscataqua Region Estuaries Partnership (PREP), which is based at UNH and covers 52 cities and towns in coastal New Hampshire and southern Maine.
Dave Kellam, a project coordinator with PREP, said increased funding for the NEP and an emphasis on planning for rising seas are welcome steps to prepare for an uncertain future — and especially on protecting the coastal salt marshes already under pressure from development, which is leading to increased wastewater contamination.
"All those salt marshes provide an important buffer," Kellam said. "If we have sea level rise without smart planning, the buffer goes away."
The impact of rising sea levels in the region may already be unfolding in the form of increased flooding due to larger storm surges and overall increased precipitation that is testing drainage patterns. PREP conducted a major study of the culvert system in the Oyster River region, inspecting 110 culverts and making planning recommendations to local communities because the current system may not be sufficient to handle increased water flows.
Smart planning will not be an easy concept to implement for an issue that seems either too far into the future or comes with uncertainty about precise amounts of actual rising — and one tied to the politically controversial concept of global climate change. Jim Titus has researched the sea level rise dilemma for the U.S. Environmental Protection Agency since 1982 and believes a reasonable estimate of sea level rise for the Eastern Seaboard is 1 to 5 feet by the year 2100.
Titus is co-author of a yet unpublished EPA study on sea level rise from Massachusetts to Florida that was eight years in the making with a cost of $3 million (the 300-page and digital mapping report was abandoned before mapping and assessments of New Hampshire and Maine were undertaken). He said the point of the study — which has been released in various truncated forms — was to create a "dialogue" to begin the education and planning process at local, state and federal levels.
It was also designed to start consideration on the three main adaptation choices facing planners — retreat, hold back the sea or elevate the land. Titus said all three have positive attributes and potentially dire consequences. For example, holding the sea back with a series of sea walls and dikes put communities potentially in the same below sea level danger as New Orleans.
"Planning is the only way to avoid the eventual elimination of coastal wetlands and the potential disasters from having a lot of cities below sea level," Titus said. "We will have to resist the temptation to develop some low-lying areas — and people will have to move out of many low areas that have been developed."
Titus acknowledges the political and social difficulties of such planning.
"It's never been done on a large scale," he said. "The study and the planning maps provide a starting point, a template. To really plan for sea level rise will require the local comprehensive plans to indicate which areas will be protected and which will be available for wetlands to migrate inland."
How might sea level rise play out on the Seacoast? Derek Sowers, a program manager with PREP, said it was difficult to assess the exact impacts on the region's ecosystem due to sea level rise because of varying locations and circumstances. He said a rapid sea level change could have the largest impact on the Hampton-Seabrook estuary, the largest salt marsh habitat in the state.
"Marshes can adapt to gradual sea level rise changes — the problem with rapid changes in sea level rise is that it outpaces the natural processes that enable marshes to cope," Sowers said. "In many areas along marsh shorelines in New Hampshire there is a somewhat distinct topographic break between the existing marsh plain and upland habitat. This means that if a marsh 'drowns' under sea level rise there is not much opportunity for the marsh habitat to simply 'migrate' to higher areas that are now upland."
One thing Titus wants to see is responsible policy debate about sea level rise options and not sensationalist posturing or dire media stories. He said the larger debate over climate change and emission policies should not overwhelm "a middle way" to prepare for and adapt to the real consequences of rising sea levels.
"Researchers and the media need to stop suggesting that Manhattan or even Miami will be lost to a rising sea," Titus wrote. "That's not realistic; it promotes denial and panic, not a reasoned consideration of the future. Our maps show some of the choices coastal residents face, but losing Manhattan is not one of them."