Lake Drummond and Great Dismal Swamp

southeast Virginia, showing Lake Drummond and Union Camp holding ponds to west (at City of Franklin, near Blackwater River)
southeast Virginia, showing Lake Drummond and Union Camp holding ponds to west (at City of Franklin, near Blackwater River)
Source: NASA - Stennis Space Center

Lake Drummond is named for a former North Carolina governor who had been an ally of Governor Berkeley of Virginia, but then chose the wrong side in Bacon's Rebellion in 1676. After the rebellion collapsed, the last words of Governor Berkeley to William Drummond were "Mr. Drummond, you are very welcome. I am more glad to see you than any man in Virginia. Mr. Drummond, you shall be hanged in half an hour."1

The lake is one of just two natural lakes in Virginia. Mountain Lake (in Giles County) may have formed on Salt Pond Mountain by eroding a basin into an unusual structure in the Clinch Sandstone formation. There, cracks in the sandstone have formed a depression allowing water to seep underground, etching a lake basin in the bedrock. Intermittently, the cracks are opened (allowing Mountain Lake to drain and be replaced by a meadow) or blocked (causing the lake to reform).

The creation of Lake Drummond is even more mysterious. Geologically, Lake Drummond is an unusually large (3,108 acre) open body of water on the Coastal Plain, east of the Suffolk Scarp. The scarp marks the location of the Atlantic Ocean shoreline and barrier islands roughly 125,000 years ago, when temperatures were higher, the ice melted off the southern half of Greenland, and sea level was higher.2

The scarp is used today to separate the Outer Coastal Plain (including Lake Drummond) vs. the Middle Coastal Plain west of the scarp. The 30' high scarp separates terraces of flat sediments to the east and west. To the east, the Norfolk Formation was deposited on top of the clay-rich Yorktown Formation, and the sandy sediments provide the groundwater recharge area for the Great Dismal Swamp National Wildlife Refuge.

Lake Drummond is located east of the Suffolk Scarp on the Coastal Plain, 18' above sea level
Lake Drummond is located east of the Suffolk Scarp on the Coastal Plain, 18' above sea level
Source: US Geological Survey (USGS), A Surficial Hydrogeologic Framework for the Mid-Atlantic Coastal Plain (Plate 1)

At normal water levels, the lake is 6-7 feet deep and the surface is 18 feet above sea level. There is little topographic relief in the area; elevation drops at one foot per mile near the lake.3

There's no obvious reason for one big lake to exist in the middle of the Great Dismal Swamp, which extended all the way to Back Bay/Albemarle Sound in the colonial era. There is no network of streams draining a watershed upstream and emptying into the lake. Lake Drummond is a high point in the middle of the remnants of the swamp.

In fact, ditches - including some dug during the time when Virginia was a colony, such as "Washington Ditch" initiated by George Washington - are supplied naturally with water that drains by gravity out of the lake. When lake level drops to 15.75 feet, the U.S. Army Corps of Engineers stops releasing water from Lake Drummond to supply the Dismal Swamp Canal. As described by the US Fish and Wildlife Service:4

The Great Dismal Swamp is less than 9,000 years old; it was formed on a hillside instead of a basin and without the benefit of rivers flowing into or beside it.

The origin of the swamp dates back to the end of the last ice Age:5

Evidence indicates that the Dismal Swamp first began to develop along streams 11,000 to 12,000 years ago. A previous ice advance had left the area with characteristic boreal vegetation of jack pines and spruces. Over a period of 3,000 to 4,000 years the boreal vegetation was replaced by northern hardwood species that, in turn, was replaced by oaks, hickories, and other endemic southeastern species.

The swamp gradually expanded westward along watercourses and peat began to accumulate. By 3,500 years ago, peat had blanketed the present-day Dismal Swamp, the water regime was saturated, and the oak-hickory forest was replaced by a cypress-gum swamp.
Lake Drummond
Lake Drummond
Source: US Fish and Wildlife Service

Geologically, the swamp and lake formed on top of coarse sand that is very permeable, but with layers of clay and silt that block water flow. An organic layer of peat has accumulated at the surface, and is up to five feet thick. Underneath the peat is the Sandbridge Formation, with upper layer of silty clay and a lower layer of sand. The next layer down is the London Bridge Formation, mostly clay silt, and then layers of sand and silt called the Norfolk Formation. The Norfolk Formation is exposed to the west of the swamp at the Suffolk Scarp:6

This is the groundwater recharge area for the aquifer... Groundwater input from the Norfolk Formation accounts for the majority of water that upwells in the swamp.

One possibile way Lake Drummond was formed: a natural fire could have burned a "hole" in the peat of the Great Dismal Swamp. In 2011, during a severe drought, one of the largest wildfires in the modern history of Virginia burned over 6,000 acres of the swamp. The "Great Conflagration" of 1923-26 was probably even more significant.7

Dismal Swamp on fire, 2011
Dismal Swamp on fire, 2011
Source: US Fish and Wildlife Service (Mike Petruncio/North Carolina Forest Service)

Perhaps 9,000 years ago, a lightning strike may have triggered an extraordinary fire that burned hot enough to destroy the peat layer, reaching down to the confining clay layer that keeps the water in the swamp from draining into the sand underneath. Such a fire could have carved out a bowl within the deep peat, creating a hole that developed into Lake Drummond.

ditches drain Lake Drummond, especially Feeder Ditch connecting the lake to the Dismal Swamp Canal at Arbuckle Landing
ditches drain Lake Drummond, especially Feeder Ditch connecting the lake to the Dismal Swamp Canal at Arbuckle Landing
Source: US Geological Survey, Lake Drummond 7.5x7.x topographic map (2011)

Another posibility: Lake Drummond resembles may other elliptical "bays" or small lakes on the Coastal Plain of the Eastern United States, from Florida to New Jersey, with a southeast-northwest orientation. They might have formed naturally in the Pleistocene as the climate changed, perhaps comparable to the formation of modern lakes on the Arctic Coastal Plain. The elliptical pattern could have been caused by winds blowing from the southwest and forming sand ridges, which have since been vegetated (and in some cases flooded to form lakes) as rainfall increased in the last 20,000 years.8

Yet another possible cause: Lake Drummond was formed by an icy comet/meteor ("bolide") that broke up in the atmosphere and peppered the Coastal Plain. Meteorite fragments are rare in the area, so there is insufficient evidence to claim the lake is a meteor crater. However, shock waves from a comet exploding above the surface of the earth could have carved out the initial depressions, which then filled with water and have been covered with vegetation.

Fragmentation of an extra-terrestrial comet in the atmosphere might explain the regular pattern of the ellipses, their large number (roughly 500,000), and the absence of meteorite fragments. (Comets, because of their icy composition, leave no trail of "meteorites" to record their impact or disintegration in the lower atmosphere.) The Younger Dryas period of global cooling, 12,800 years ago, could have been triggered by a comet's impact. Lake Drummond could be a larger-than-usual Carolina Bay, formed recently as earth's surface was disturbed by a dying comet.9

Dismal Swamp Canal, a Corps of Engineers project
Dismal Swamp Canal, a Corps of Engineers project
Source: US Army Corps of Engineers, Atlantic Intracoastal Waterway General Information

The ground surrounding Lake Drummond includes dry land as well as swamp. The dry land is typically peat (dead vegetation that has not decomposed yet, or been compressed into lignite/coal) with sand underneath. Such soil is unsuitable for agriculture, but Atlantic White Cedar (Chamaecyparis thyoides) used to thrive in places high enough for plant roots to grow above the water table.

The cedar is a pioneer species, capable of regrowing from seed after fires/storms and forming dense stands. It is not an "old growth" species that replaces itself, perpetuating Atlantic White Cedar forests indefinitely. Without disturbance, other species such as red maple ultimately dominate land originally covered by Atlantic White Cedar trees.

As one researcher noted:10

The most extensive development of AWC [Atlantic White Cedar] forests occurred on medium to deep peat soils with fire intervals of 100-300 years...

One hundred years allows stands to mature and accumulate an extensive seed bank in the upper few inches of peat. Three hundred years is the approximate longevity of AWC, but at that age, too few trees still remain on the site to maintain a good seed bank or prevent succession to other species...

Atlantic White Cedar has a grain that makes it easy to split/saw. The high resistance to rot also made the species a high-value target for lumber companies. Most forested areas east of the Great Dismal Swamp were harvested in the 1700-1900's, and much of the remaining timber was burned by wildfires.

Forest regeneration was blocked where land was timbered, then ditched and drained for planting crops. Efforts to drain swamps altered the hydrologic regime, triggering the growth of hardwoods and blocking reproduction of Atlantic White Cedar. By one description, the cedar forest were "mined" rather than "managed."11 By the 1950's, the Great Dismal Swamp was one of the last remaining areas with a substantial Atlantic White Cedar forest.

The Union Camp Corporation, a lumber company, donated 49,000 acres of logged-over swampland to The Nature Conservancy in 1973, and the non-government organization then transferred the property to the Federal government. Today, Lake Drummond is in the middle of the Dismal Swamp National Wildlife Refuge, managed by the US Fish and Wildlife Service in the Department of the Interior. Further land acquisition has expanded the refuge to over 110,000 acres, but that is only 10% of the size of the original swampland existing before European colonization.12

One goal of the US Fish and Wildlife Service is to re-plumb the swamp in order to restore the natural flow of water. The Federal agency, together with Dismal Swamp State Park in North Carolina, manages 42 water-control structures (and hopes to install 35 more) to undo the effects of ditches and logging roads that have created drier-than-natural and wetter-than-natural areas. The organic soils in the swamp are normally 85-95% water. When those soils dry out, the soil particles alter into a granular form that will not absorb water even after water levels rise again. The soil then oxidizes away, adding carbon to the atmosphere. Keeping the soils saturated is essential for minimizing the intensity and size of wildfires in the Great Dismal Swamp.13

Hurricanes and major forest fires, influenced by the altered drainage, alter the ecosystem even more rapidly. In 2003, Hurricane Isabel flattened 80% of the purest cedar stands in the refuge, after soil dried out and roots were unable to withstand the wind pressure. Fires - and prevention of fires - threaten the continued existence of the Atlantic white cedar plant community:14

Many communities within the GDS [Great Dismal Swamp] are pioneer or early successional species, which will be replaced by longer-lived climax species if not disturbed. These communities include the Atlantic white cedar, shrub pocosin, marsh and sphagnum bog. Each of these vegetative communities was historically a result of wildfire and/or maintained by fire. Wildfires have been aggressively suppressed since the 1940’s resulting in reduced size and vitality of dominant species. With the changes in water regime throughout the swamp and the surrounding urbanization, permitting drought-driven wildfires to burn today is not an option.

Management of these communities must create the disturbance required for regeneration or maintenance. Strategies include the use of herbicides, and/or timber sales to reduce competition, surface preparation completed by scarifying with heavy equipment, and/or carefully conducted site preparation prescribed burns...

The refuge cannot manage the adjacent cropland to slow incoming surface water, nor can it abandon or remove the roads within the swamp because compaction has already altered the substrate and road access must be maintained to fight wildfires. The refuge cannot abandon the ditches because the clay-confining layer cannot be replaced over the aquifer.

The refuge can operate and maintain a number of water control structures that slow discharge of both surface and ground water from the swamp and serve to mitigate many of the impacts of these developments.
forest with Atlantic White Cedar at Dismal Swamp
forest with Atlantic White Cedar at Dismal Swamp
Source: US Fish and Wildlife Service National Digital Library

The 100 miles of ditches within the Great Dismal Swamp have resulted in a lower water table, draining away rainfall before it can seep into the peat. The moist soil, essential to growth of the Atlantic White Cedar, has dried out. In 2011, a fire started in early August and burned for 110 days. The 12" of rain that fell during Hurricane Irene in late August drained out of the swamp so quickly that the wildfire was not drowned by the massive amount of rain.15

In 2013, Federal land managers installed new weirs to raise water levels in the ditches, hoping to re-saturate the peat and restore the natural ecosystem over time. The US Fish and Wldlife Service proclaimed that re-watering 9,500 acres, by controlling flow in South Martha Washington Ditch and Kim Saunders Ditch, was the largest restoration project for forested wetlands east of the Mississippi River. Keeping the peat wet was predicted to trap an amount of carbon equal to what 16 million cars emit annually.16

multiple ditches drain Lake Drummond and Great Dismal Swamp
multiple ditches drain Lake Drummond and Great Dismal Swamp
Source: US Geological Surcey (USGS), The National Map - Hydrography

Water levels of the lake and swamp are controlled by Federal land managers. Bear/deer hunting is authorized, so the "natural" character of the refuge is modified by human action, but insects are protected as part of the natural food chain.

A wet Dismal Swamp provides excellent habitat for beeding mosquitoes in the summer; visitors to the 113,000-acre wildlife refuge get to experience annoying as well as attractive critters. The mosquitoes are considered wildlife, like bears and birds. Because the Great Dismal Swamp National Wildlife Refuge is Federally-protected, the City of Suffolk is not allowed to spray chemicals within the refuge to kill the mosquitoes.17

The effect of that prohibition extends beyond the refuge boundaries. Mosquitoes are the primary vector that transfers Eastern equine encephalitis (EEE) and West Nile virus from birds in the refuge to horses and humans in the cities of Suffolk and Chesapeake. There is a tradeoff between protecting natural processes in natural areas vs. protecting human health. People and horses in South Hampton Roads have a higher risk of exposure to some diseases, because the habitat and animal populations (including mosquitoes) within Great Dismal Swamp National Wildlife Refuge are protected.

Dismal Swamp National Wildlife Refuge
Dismal Swamp National Wildlife Refuge
Source: US Fish and Wildlife Service Great Dismal Swamp National Wildlife Refuge brochure

Why are there only two natural lakes in Virginia?

Over 200 million years of steady erosion in Virginia has allowed streams to etch their way into every Virginia valley. The stream channels have drained whatever lakes may have formed long ago in the last major orogeny, when the Appalachian Mountains were lifted up and topography transformed. In the most recent Ice Ages, no new lakes in Virginia were scoured out by the ice sheets - in contrast to places such as Minnesota, where melting glaciers transformed the landscape and created lakes (including the Great Lakes) in the last 100,000 years.

The millenia of erosion destroyed all lakes created since the Appalachian Orogeny, and the two natural lakes present today appear to have been created by recent events. All other "lakes" in Virginia, including small ones such as Burke Lake in Fairfax County and large ones such as Smith Moutain Lake near Roanoke, are human-made reservoirs created by building dams and flooding valleys.

Lateral West Forest Fire burns towards Corapeake Ditch at Great Dismal Swamp National Wildlife Refuge, 2011
Lateral West Forest Fire burns towards Corapeake Ditch at Great Dismal Swamp National Wildlife Refuge, 2011
Source: US Fish and Wildlife Service, National Digital Library

Links

in 1954, the new City of Chesapeake had replaced Norfolk County on the eastern edge of Lake Drummond, but the City of Suffolk had not yet replaced Nansemond County on the west
in 1953, the new City of Chesapeake had replaced Norfolk County on the eastern edge of Lake Drummond, but the City of Suffolk had not yet replaced Nansemond County on the west
Source: US Geological Survey (USGS), Lake Drummond 7.5x7.5 topographic map (1953)

a portion of Lake Drummond is located in the City of Suffolk, but all of the Feeder Ditch leading to the Dismal Swamp Canal at Arbuckle Landing is within the City of Chesapeake
a portion of Lake Drummond is located in the City of Suffolk, but all of the Feeder Ditch leading to the Dismal Swamp Canal at Arbuckle Landing is within the City of Chesapeake
Source: US Geological Survey (USGS), Lake Drummond USGS Topo Revision 1 (2013)

References

1. Dictionary of Virginia Biography. (2010, June 9). William Drummond (d. 1677). Retrieved September 12, 2010, from Encyclopedia Virginia: http://www.EncyclopediaVirginia.org/Drummond_William_d_1677 (last checked September 12, 2010)
2. "Extreme Ice," NOVA, Public Broadcasting System (PBS), March 24, 2009, http://www.pbs.org/wgbh/nova/earth/extreme-ice.html (last checked December 19, 2013)
3. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," US Fish and Wildlife Service, July 2006, p.36, p.44, http://library.fws.gov/CCPs/GDS/greatdismalswamp06.pdf (last checked September 9, 2012)
4. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," p.41, p.44
5. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," p.60
6. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," pp.37-38
7. "The Great Dismal Swamp a year after the fire," Chicago Tribune, August 4, 2012, http://www.chicagotribune.com/news/dp-nws-great-dismal-swamp-20120804,0,6818233,full.story; "Great Dismal Swamp wildfire still burning after more than 2 months," The Washington Post, October 6, 2011, http://www.washingtonpost.com/national/health-science/2011/10/05/gIQALlJYRL_story.html (last checked September 9, 2012)
8. Robert E. Carvera, George A. Brook, "Late pleistocene paleowind directions, Atlantic Coastal Plain, U.S.A," Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 74, Issues 3–4 (30 November 1989), http://dx.doi.org/10.1016/0031-0182(89)90061-8 (last checked September 9, 2012)
9. James H. Wittke, James C. Weaver, Ted E. Bunch, James P. Kennett, Douglas J. Kennett, Andrew M. T. Moore, Gordon C. Hillman, Kenneth B. Tankersley, Albert C. Goodyear, Christopher R. Moore, I. Randolph Daniel, Jr., Jack H. Ray, Neal H. Lopinot, David Ferraro, Isabel Israde-Alcántara, James L. Bischoff, Paul S. DeCarli, Robert E. Hermes, Johan B. Kloosterman, Zsolt Revay, George A. Howard, David R. Kimbel, Gunther Kletetschka, Ladislav Nabelek, Carl P. Lipo, Sachiko Sakai, Allen West, and Richard B. Firestone, "Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago," Proceedings of the National Academy of Sciences (PNAS), published ahead of print May 20, 2013, http://dx.doi.org/10.1073/pnas.1301760110; J. Ronald Eyton, Judith I. Parkhurst, "A Re-Evaluation Of The Extraterrestrial Origin Of The Carolina Bays," April 1975, http://abob.libs.uga.edu/bobk/cbayint.html; Michael Davias, "Correlating the Orientation of Carolina bays to a Cosmic Impact," http://cintos.org/SaginawManifold/introduction/index.html (last checked May 26, 2013)
10. John E. Kuser, George Zimmermann, "Restoring Atlantic White-Cedar Swamps: A Review of Techniques for Propagation and Establishment," Tree Planters Notes, Volume 46, Number 3, Summer 1995, http://www.stockton.edu/~wcedars/treeplnt.html (last checked July 6, 2013)
11. L. Eric Hinesley, "Research at N. C. State University related to regeneration of Atlantic White Cedar (AWC) and Baldcypress," US Fish and Wildlife Service, August 2002, http://www.fws.gov/nc-es/coastal/plnwrawc/atlanticwhitecedarresearch.html (last checked July 6, 2013)
12. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," p.4; Aimlee D. Laderman, "The Ecology Of Atlantic White Cedar Wetlands: A Community Profile," US Fish and Wildlife Service Biological Report 85, July 1989, p.19, http://www.nwrc.usgs.gov/techrpt/85-7-21.pdf (last checked July 6, 2013)
13. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," pp.38-39; "Swamp’s 'Hoover Dam' dedicated," Suffolk News-Hearal, December 18, 2013. http://www.suffolknewsherald.com/2013/12/18/swamps-hoover-dam-dedicated/ (last checked April 15, 2014)
14. "Great Dismal Swamp National Wildlife Refuge and Nansemond National Wildlife Refuge Final Comprehensive Conservation Plan," pp.21-22, p.59
15. "Dam-like devices will help fight fires at Dismal Swamp," The Virginian-Pilot, December 19, 2013, http://hamptonroads.com/node/700673; "Great Dismal Swamp wildfire still burning after more than 2 months," Washington Post, October 6, 2011, http://www.washingtonpost.com/national/health-science/2011/10/05/gIQALlJYRL_story.html (last checked April 15, 2014)
16. "Largest Wetland Restoration East of the Mississippi Dedicated at Great Dismal Swamp National Wildlife Refuge," US Fish and Wildlife Service, December 18, 2013, http://www.fws.gov/fieldnotes/regmap.cfm?arskey=34553 (last checked April 15, 2014)
17. "Regulations are barriers to mosquito control in Suffolk," The Virginian-Pilot, July 6, 2013, http://hamptonroads.com/node/682517 (last checked July 6, 2013)

Jerico Ditch, Great Dismal Swamp National Wildlife Refuge
Jerico Ditch, Great Dismal Swamp National Wildlife Refuge
Source: US Fish and Wildlife Service, National Digital Library

Dismal Swamp National Wildlife Refuge
Dismal Swamp National Wildlife Refuge
Source: US Fish and Wildlife Service Great Dismal Swamp National Wildlife Comprehensive Conservation Plan

Dismal Swamp Lateral West fire from space, August 2011
Dismal Swamp Lateral West fire from space, August 2011
Source: NASA Earth Observatory Fire in Great Dismal Swamp, Virginia)


Lakes, Dams, and Reservoirs
Draining the Swamps of Virginia
Rivers and Watersheds
Virginia Places