Interior aims to fight floods and fire by restoring a swamp

Interior aims to fight floods and fire by restoring a swamp

30 October 2013

USA — Hoping to rein in both carbon-releasing peat fires and post-hurricane floods, the Department of the Interior is betting $3.13 million on 15 small dams in a Virginia wildlife refuge.

Officials say these structures will help restore a natural water balance to the Great Dismal Swamp Wildlife Refuge in Virginia and North Carolina, undermined since the 1700s when farmers and loggers started to build ditches and drain the area. By better controlling the water running through the 150-mile ditch network that now crisscrosses the refuge, U.S. Fish and Wildlife Service hopes to both mitigate regional weather disasters and adapt to the future impacts of climate change.

Brian van Eerden, director of the Nature Conservancy’s Southern Rivers Program, explained that the water management project has the potential to be a “transformational moment” for the refuge and nearby communities.

“This is a great example, we think, where there are a lot of very tangible benefits for folks in [Virginia’s] Hampton Roads region, and there are also really important benefits for natural resources,” van Eerden said.

This effort is one of 45 Interior projects that received a total of $162 million last week for post-Superstorm Sandy research and restoration efforts (Greenwire, Oct. 24). Yesterday, Interior Secretary Sally Jewell announced an additional $100 million in competitive grants to fund similar projects.

“By stabilizing marshes and beaches, restoring wetlands, and improving the resilience of coastal areas, we not only create opportunities for people to connect with nature and support jobs through increased outdoor recreation, but we can also provide an effective buffer that protects local communities from powerful storm surges and devastating floods when a storm like Sandy hits,” Jewell said in a statement announcing the funding.

Controls to soak up a flood …

The Great Dismal Swamp encompasses 111,200 acres of wetland forest that is home to a large population of black bears and more than 200 species of birds. Nearly half this land was owned by the Union Camp Corp., a paper company, until 1973. That year, the company donated more than 49,000 acres to the Nature Conservancy, which then turned it over to Interior.

The ditches and roads left behind from logging activity irreversibly disrupted the swamp’s hydrology, and the new project is a continuation of ongoing habitat restoration efforts by the Nature Conservancy, the Virginia Department of Game and Inland Fisheries, the U.S. Geological Survey, and the Fish and Wildlife Service.

But in awarding the refuge more than $3 million for water management from Congress’ $50 billion Sandy recovery package, Interior is acknowledging the project’s potential for storm protection.

By either installing or repairing 15 water control structures in ditches in the northern portion of the refuge, FWS hopes to better manage the refuge’s ability to soak up extreme rainfall events like a giant sponge and protect nearby towns.

In dry conditions, the water control structures act like dams, holding water levels in the ditches high and keeping the surrounding land moist and healthy.

“That native habitat needs a lot of water,” said Mark Bennett, director of the Geological Survey’s Virginia Water Science Center, who oversees research on the refuge’s overall hydrology. “The purpose of the gates is to keep a lot of that water in.”

But when it looks as if there might be too much water heading toward southern Virginia in the form of a hurricane, these structures, which cost $40,000 to $1 million, can be opened to help offset heavy precipitation.

“If the swamp is already wet and we know a hurricane’s coming, we can let the water out so we can store more of the precipitation,” explained Chris Lowie, refuge manager for the Great Dismal Swamp.

… and dampen peat fires

By holding water in the swamp during dry conditions, the water management project also has the potential to dampen the impacts of wildfires and the massive release of carbon that comes with them. Fires on the swamp’s peat soils can drag on for months in drought conditions because the ground itself burns to depths of around 4 feet.

In 2008, a 121-day wildfire in Great Dismal burned about 4,800 acres. In 2011, a second fire in the same area burned close to 6,400 acres and lasted 111 days. The length of these fires made putting them out especially costly, ultimately costing the federal government $25 million.

But the fires were also costly for the global carbon budget. Wildfires “chew into the peat and can burn up thousands of years of carbon in a matter of weeks,” van Eerden said. “One thing about peat lands, they only occupy about 3 percent of the world’s surface, but the carbon that they contain is twice the carbon contained in all the forest biomass across the world.”

According to Lowie, the 2008 and 2011 fires released an estimated 4 million metric tons of carbon into the atmosphere.

“The cost of doing this hydrological restoration is minuscule compared to suppressing these wildfires,” he said. “We will have fires, but the key is hopefully they are shorter in duration because they won’t burn as deep and as long. … We want to be a carbon sink, not a carbon source.”

The project is not intended to prevent all forest fires, which van Eerden stressed were a natural part of the region’s ecology. “It’s really important that we not paint fire as the bad guy,” he said.

The project also won’t entirely save nearby communities of Chesapeake and Suffolk, Va., from flooding when hurricane-borne deluges pass over the area.

“These communities and these farmlands are in the historic swamp. … Anytime you have a significant amount of rain, they’re going to get wet,” Lowie said.

But the new or improved structures, which the agency hopes to complete within the next three years, will add a measure of control over future flooding and fire events.

Chesapeake welcomed the news of the new project: “We’ve had a very strong working relationship with Fish and Wildlife,” said Heath Covey, a spokesman for the city. “We are extremely pleased that they’ve gotten this money, and we look forward to continuing to partner with them.”

24. November 2017/by GFMCadmin