Enviros Fault Army Corps’ Plan for Defending NJ Back Bays from Rising Seas

Groups say nature-based measures should be a bigger part of massive plan to protect communities

Credit: wikimedia.org
Flooding in Ocean City
Environmental groups faulted some of the U.S. Army Corps of Engineers’ latest ideas for defending New Jersey’s back bays from the devastation of sea-level rise and the bigger storms that are expected to come with climate change.

In March, the Corps proposed measures including sea walls and storm-surge barriers, as well as nature-based programs like building up coastal marshes, as ways of keeping ocean waters out of vulnerable back-bay communities.

The handily titled New Jersey Back Bays Coastal Storm Risk Management Feasibility Study Interim Report invited but did not publish reactions from stakeholders including municipalities, other government agencies, and environmental groups. New Jersey’s Department of Environmental Protection is cooperating in the project and sharing the cost with the Corps.

The comments, obtained from some of the groups individually, welcomed the investigation into ways of protecting the back bays from rising waters but said the plan missed the mark in some important respects.

Crucial role of coastal marshes

The Nature Conservancy in New Jersey, for example, said the proposals did not give enough weight to nature-based measures — called ‘NNBF’ — such as coastal marshes and living shorelines that play a crucial role in absorbing storm surge.

“We were disappointed that NNBF has not been fully integrated into the flood-risk management alternatives,” the conservancy wrote. “We strongly urge the USACE to more comprehensively utilize NNBF as a flood-risk management strategy along the NJ coastline.”

It offered its own research into which coastal habitats are already helping to mitigate sea-level rise; said it was ready to identify which salt marshes in Ocean, Atlantic and Cape May counties would benefit from an increase in sediment, and proposed to share its ideas on building different kinds of living shorelines to defend different parts of the Jersey Shore.

Click to expand/close
Flood barriers like sea walls “may provide a false sense of security” because they encourage new development and increasing population in low-lying areas, and may distract from the need to encourage people to move away from flood-prone areas, the conservancy said.

While some man-made infrastructure will likely be needed to protect the back bays, features like storm-surge barriers could hurt natural resources, and that isn’t fully recognized by the corps’ report, said Patty Doerr, director of the conservancy’s coastal and marine program in New Jersey.

She said conservancy scientists have found that salt marshes, for example, play an important role in protecting the coast from storms, including superstorm Sandy in 2012 when coastal marshes reduced property damage by $450 million, according to a study by the conservancy and others.

Impact of new barriers on habitat

“We’re going to need some great infrastructure but keeping salt marshes in place and keeping beaches and dunes healthy is going to be key,” she said. “We’re really concerned about the impact of storm-surge barriers and flood walls on those habitats.”

Credit: USACE
Existing before a floodwall
Credit: USACE
With a floodwall
Doerr also said the slow pace of the study — which is not expected to be implemented until 2030 at the earliest, depending on Congressional appropriations — could mean that its conclusions will be out of date by the time it is finalized. “What the coast looks like in 10 years could be different, and does that all make sense in terms of what they are proposing?” she asked.

A spokesman for the Corps said it is working with the conservancy on ways of integrating nature-based measures into the plan. It’s not likely that those measures alone can defend the back bays from rising waters, but they may be able to play a role, he said.

New Jersey Sierra Club director Jeff Tittel also criticized plans for infrastructure like sea walls, saying they just divert rising waters and storm surges into unprotected areas.

“The problem with sea walls and gates is that water goes around them,” he wrote. By preventing tidal movement, such measures stop pollutants flushing out of the system and hurt fisheries, he said.

Focus on buying out rather than building?

Rather than building sea walls, New Jersey should focus on buying out the most vulnerable homeowners, elevating properties in flood-prone areas, and building up dunes, Tittel said. He called the Corps’ report “a recipe for disaster” that does not recognize the realities of sea-level rise.

Responding to Tittel’s criticism, the Corps said it is working to understand how storm-surge barriers affect tidal flows and salinity, and is working with other agencies on a “conceptual ecological model” to evaluate the impacts of the barriers.

Credit: USACE
Jersey Shore
According to Rutgers University scientists, the consensus projection for sea-level rise at the Jersey Shore is that seas will be 1-2 feet higher in 2050 than they were in 2000. By 2100, seas will be 2.5 to 5 feet higher, the estimates say.

The Barnegat Bay Partnership, representing federal, state, municipal, academic and business groups working to protect the bay, said it is concerned about impacts to natural features like wetlands from the Corps’ plan.

The partnership commended the Corps for its “substantial undertaking” but said the report had omitted data on issues such as water-quality modeling around storm-surge barriers and so had made some decisions based on “little information and/or a limited understanding.”

It welcomed the Corps’ consideration of managed retreat and relocation as one response to coastal inundation but questioned why that option was not given a higher score in an assessment of feasible approaches, while man-made structures got a higher rating.

Bias toward ‘structural components’

“These inconsistencies appear to bias upwards the rankings of structural components,” the partnership’s submission said.

And it accused the Corps of underestimating how much a 5-10-foot storm-surge barrier would restrict access to coastal waterways for boaters.

“To suggest that the ‘potential effect would require further evaluation to determine the extent of this impact’ is to ignore the obvious fact that the impact may be significant,” it said.

Comments were also submitted by Surfrider Foundation, a nonprofit that represents beach and ocean users. It accused the Corps of not doing enough to include all stakeholders in its discussions.

“Considering the scale of the potential project and the far-reaching impacts to the environment, human uses and coastal communities, outreach for the study requires a slower, more in-depth approach,” it said. “We can say with certainty that the majority of affected stakeholders do not know that the study exists.”

About a quarter of the 112 comments, the biggest proportion, addressed the environmental impacts of structural features like storm-surge barriers, the Corps said in a summary of the responses. Others called for more attention to be paid to sea-level rise projections, and how to manage its risk.

The Corps said it hopes to hold more public meetings in winter this year, and then in spring 2020 to mark the release of a draft feasibility report as the next stage in the massive, multi-year project that covers 3,400 miles of shoreline in five counties.