WASHINGTON—Most beach-goers probably figure the sand beneath their feet is as endless as the waves lapping at the shore.
But they would be wrong. And Jeffrey Reidenauer of the U.S. Interior Department has the proof.
He heads the tiny Marine Minerals Division housed within the Bureau of Ocean Energy Management. Its 15 employees track the offshore sand destined to restore beaches devastated by the swell of ever-wilder hurricanes slamming—and rearranging—U.S. coastlines.
The recent trend of growing demand for federal sand to execute ever-larger projects has Reidenauer’s division on edge about supply.
In response, employees are in the midst of creating a comprehensive inventory of sand available in federal waters.
“These are finite resources,” he told a lunchtime audience Oct. 3 in downtown Washington. “I kind of look at this….like your personal bank account. You’re not going to be writing checks if you don’t know how much is in your account.”
Climate change and the increasing frequency and fierceness of hurricanes such as Sandy in 2012, Matthew in 2016, Harvey, Irma and Marie in 2017 and Florence and Michael this year have made the inventory a BOEM priority.
“We need to know where resources are located and how much is available before we can begin responsibly issuing leases and agreements,” he said.
Reidenauer offered multiple insights during his hour-long talk at the Rachel Carson Room in the Stewart Udall Interior Building.
Here’s a Top 10, of sorts, on why those grains so many take for granted matter in the big picture:
1) What beaches have benefited from federal sand?
On the East Coast, Jacksonville and Cocoa beaches in Florida, Myrtle Beach in South Carolina, the Outer Banks in North Carolina, Virginia Beach in Virginia and Long Beach Island in New Jersey are just some of the places that have been “renourished” with federal sand at least once.
2) Is the sand for beaches alone?
No, it is also used to restore federal coastal assets such as military and flight installations.
For instance, one project added 3 million cubic yards of sand to Wallops Island in Virginia where NASA operates a flight facility worth $1 billion. That project, which reconstructed about four miles of buffer shoreline adjacent to a sea wall around the barrier island, was completed shortly before Hurricane Sandy hit.
3) What kind of volume are we talking?
The sand is harvested by giant, specially equipped ships called hopper dredges. Ten million cubic yards of sand is enough to fill the Empire State Building about seven times.
For perspective, consider that a recent Gulf of Mexico project required nearly 20 million cubic yards of sand for coastal improvements in Mississippi.
Farther north, 10 million cubic yards restored 12 miles of shoreline along New Jersey’s Long Beach Island. Dredging for that project, the largest on the Atlantic Coast, ended on Sept. 30.
4) Why are states using federal sand instead of their own?
Supplies of state sand are playing out. Dredging done from those close-to-the-beach sites mean large waves and storms can cause even more shoreline erosion.
Federal waters, which extend out three miles in most places, have larger shoals.
Eight states have made agreements to use federal sands on some 54 projects, including the above-mentioned ones in Mississippi and New Jersey. As well, New York and Delaware are making requests.
5) How do hopper dredges work?
Basically, they vacuum up the sediment about one foot deep and store it in the hull. They are equipped to operate in water up to 100 feet deep.
The highest quality harvests come from sand ridges, sand shoals and what are known as paleo-channels. The latter are inactive rivers and streams on the outer continental shelf that often filled in with sand as sea levels rose.
Long linear shoals are ideal because “it’s like mowing the grass” and the dredge cuts are shallow. Multiple turns burn more fuel and increase the chances of scarring the seascape with big, deep pits.
6) Who pays for federal sand?
Federal, state and local agencies are not charged for the resource. However, private entities involved in restoration projects do have to pay for it.
7) Is your division on its own with the inventory?
We’re collaborating with federal partners such as the U.S. Geological Survey and the Army Corps of Engineers, as well as state cooperative agreement partners.
One complicated undertaking is to collect and streamline huge amounts of data into an accessible format available to scientists, the public and all other stakeholders. It will include basic such as type of sand, thickness of sediment and GPS coordinates of sand “borrow sites.”
To fill in data gaps, BOEM spent $6 million to survey sand resources between Massachusetts and Miami because “it’s important to not only know where the resources are but also document where they aren’t.”
For instance, that study revealed that a large “borrow site” in state waters off the coast of northern New Jersey was no longer usable because the sand was so coarsened. Only 31 million cubic yards of its 87 million cubic yards had been dredged. Continued dredging would be complicated by issues with munitions from World Wars I and II.
BOEM needs to be proactive so “we have a roadmap already laid out. As a steward of those resources we have to think about long- term management.”
8) What are some dredging challenges?
We have to think about potential conflicts with fiberoptic cables, electric cables for offshore wind, oil and gas infrastructure, and areas designated for fishing or other mineral mining.
We also have think about how the finiteness of available sand might drive the technology so dredging can be done in deeper waters.
9) What about environmental impacts?
“The sea floor is not a beach.” Fish can swim away when sand is dredged, but not the crustaceans and other critters living in the sediment that serve as fish food.
It’s ideal to keep transport distances to a minimum to cut down on air pollution.
10) Is all sand the same?
“All sand is not created equal.” Dredged sand must be compatible with the beach being restored, so the grain size and color need to match. For instance, fine sand will erode quickly and coarse sand can change a beach’s profile, thus surprising swimmers with steep drop-offs.
And humans aren’t the only concern.
For instance, Florida’s strict matching standards for its white sand have an ecological bent because it takes into account the welfare of nesting sea turtles. A hatchling’s sex is determined by sand temperature—and white doesn’t absorb as much heat as yellow-brown. The warmer the sand, the higher the ratio of females.
Reidenauer emphasized that his division is in charge of supplying the sand, not planning restoration projects.
As the need for federal sand continues to jump, he said, there will likely be situations where multiple entities are competing for the same limited resource.
“So who gets it?” he asked rhetorically. “Is it first-come, first- served? These are issues we’re going to have to start dealing with real soon.”
*Top photo: A loggerhead sea turtle, North Carolina. All photos courtesy BOEM. More here.