Delaware’s wetlands are shrinking, leaving the state more exposed to storms and rising seas, and paying more for environmental services worth tens of millions of dollars, according to a new report from state government.
Between 1992 and 2007, the state lost 3,896 acres of vegetated wetlands, an area equivalent to the town of Smyrna, according to the report from the Department of Natural Resources and Environmental Control.
After accounting for a gain of 768 acres in natural and man-made wetlands, the state lost a net 3,126 acres during the period, the report said. It estimated that 50 percent more wetlands were lost at that time than between 1981 and 1992 when a previous survey was taken.
The biggest causes were residential development, followed by conversion to agriculture. That represents a switch from the 1981-92 period when agriculture was the biggest cause.
Around the state, the biggest losses have occurred in Sussex County, which has almost half of the state’s wetlands, and lost more than 2,600 acres during the survey period.
“Wetlands provide many services on the landscape,” the report said. “As they are lost or degraded, these services are diminished and our quality of life can be impacted, including costly damage to property.”
[caption id="" align="alignright" width="300" caption="View a slideshow of Bombay Hook National Wildlife Refuge near Smyrna, Delaware"]
Tidal wetlands in particular are also under threat from sea-level rise which would inundate virtually all of the tidal areas if oceans rise by 1 meter, the central scenario being studied separately by DNREC in its ongoing assessment of the state’s vulnerability to rising ocean levels.
Ninety-nine percent of the state’s 73,000 acres of tidal wetlands would be lost under the 1-meter rise scenario, according to early data from the report, which is being finalized and is expected to be published in the spring. The report will focus solely on the threat posed by sea-level rise; the state’s response will be the subject of a later study.
Susan Love, a planner in DNREC’s Coastal Programs unit, told participants at a biennial state conference on wetlands on Feb. 29 that the 1-meter rise would also mean a 33 percent loss of non-tidal wetlands, a 42 percent loss of protected areas such as National Wildlife Reserves, and a 15 percent loss of land in agricultural preservation districts.
Ocean levels around Delaware’s shores are rising at 3.35 millimeters a year, or about 13 inches over a century, Love said. That’s almost twice the global rate because Delaware’s land is sinking at the same time.
Higher sea levels are going to mean more frequent and more severe storms; permanent inundation of some coastal areas; saltwater intrusion of some currently freshwater areas, and a range of economic and social impacts, Love said.
The changes are going to mean different means of adaptation such as raising buildings or roads and building dikes and seawalls by people in affected areas, Love told the conference. “We are choosing how to respond to the new normal,” she said.
DNREC Secretary Collin O’Mara urged participants at the Dover conference to help the public understand how wetland loss will affect people’s everyday lives.
“This isn’t some greeny, environmental issue,” he said. “We need to find ways so that every Delawarean understands.”
Loss of wetlands causes flooding, degradation in water quality and shrinkage of wildlife habitat, O’Mara said. “This isn’t an environmental conversation, it’s a health and safety conversation.”
But many people don’t recognize the value of wetlands, said Jennifer Holmes, a DNREC official who has researched public attitudes to the areas that cover around a third of the state.
Holmes urged an audience composed largely of environmental officials, consultants and nonprofit groups to seek support for wetlands by appealing to the interests of particular groups.
Developers, for instance, are more likely to welcome the argument that a wetland enhances the value of a lot, she said.
“If you have a wetland as an amenity, you are going to save money on permitting, mitigation and monitoring,” she said. “You can sell the lot for a higher price because it’s an amenity.”
[caption id="" align="alignright" width="300" caption="The amount of wetlands lost in Delaware between 1992 and 2007 is equivalent to the size of the town of Smyrna."]
With the disappearance of wetlands identified in the new report, the state has lost more than 19,000 tons of carbon storage valued at almost $20 million, or $1.6 million a year. It’s also paying an extra $700,000 a year in municipal water treatment costs, or $9.7 million over the study period, to make up for the loss of wetland water-purification, and thousands more dollars in extra inland flood control and coastal storm protection measures.
The shrinkage of wetlands has resulted in more nitrogen, phosphorous and sediment being delivered to waterways, increased flood heights, and loss of wildlife habitat, the report found.
Jeffrey Kauffman, project director of the University of Delaware Water Resource Agency, cited Bombay Hook National Wildlife Refuge near Smyrna as one example of a recreational and environmental asset that depends on the wetlands that attract a wide variety of birdlife that in turn lures birders from all over the U.S.
The preserve earns $13.4 million a year in revenue from birdwatchers alone, and has an overall benefit-to-cost ratio of 23:1, Kauffman said.
For water-quality managers, the wetlands owned by reserves such as Bombay Hook represent a better option than a new industrial plant, Kauffman argued.
“Don’t build expensive wastewater plants,” he said. “It’s much more cost-effective to use the wetlands.”
The preservation of wetlands is one tool that will help Delaware deal with anticipated sea-level rise.
As a state that is identified by the National Oceanic and Atmospheric Administration (NOAA) as entirely coastal, Delaware is probably the only one with a statewide plan assessing the vulnerability to sea-level rise, and so may become a national model for states in their efforts to plan for the phenomenon, said Jeanne Christie, executive director of the Association of State Wetland Managers.
Some other states are conducting their own assessments in coastal zones but are uneasy about acting on any findings because they could involve relocating population or major infrastructure projects at huge expense, Christie said in an interview with DFM News.
“Some states have been reluctant because they know it’s going to be bad news,” she said.
Sea-level rise is likely to hit coastlines in big steps like hurricanes rather than the incremental increases suggested by long-term forecasts, Christie said.
“It’s not going to happen gradually,” she said. “It will be a series of large, dramatic events.”
