The central part of the county is a flat plain (the Pamlico Terrace)
that was the sea floor when sea level was higher. The entire plain
slopes gently toward the east at about six inches per mile. The
natural drainage is poorly defined because it is a young geologic
surface. In the last 10,000 years, a complex of wetlands has
developed on the surface. This is part of the largest wetland
complex in North Carolina. It covers the major part of five counties
(Washington, Beaufort, Tyrrell, Hyde, and Dare) on the peninsula
between Albemarle Sound to the north and Pamlico Sound to the south,
and is bounded to the west by the Union Chapel and Pinetown Scarps.
The central part of the wetland complex is the largest pocosin in
the world. Despite these superlatives, this wetland has no single
well-known name. In contrast to the Great Dismal Swamp of North
Carolina and Virginia, and other North Carolina wetlands such as
Open Ground Pocosin, Green Swamp, Angolan Bay, and Holly Shelter,
this wetland has no common name. McDonald and Ash (1981) simply
refer to the whole peninsula from the Suffolk Scarp to the Alligator
River as the "Washington-Hyde-Tyrrell Pocosin System". On county
road maps, the western portion in Washington and Beaufort counties
is called The East Dismal Swamp, but this name is seldom used.
Instead, parts have been given names related primarily to land
development activity. Names such as the Parker Tract, Wenona,
Wonderland, Terra Cecia, North Slope, South Slope, North Line,
Carolina Meadows, Grassy Ridge, Hyde Park, and probably others.
Drainage of the southern portion is to the Pamlico Sound by way of
Bath Creek, the Pungo River, and other streams. Drainage of the
northern part is to the Albemarle Sound by way of Conaby Creek,
Mackeys Creek, and the Scuppernong River
The wetlands of the Peninsula include the bottomland forests on the
flood plains of the Roanoke and Scuppernong Rivers, the
non-bottomland swamp forest of the central part of the county, the
cypress forest north of Lake Phelps, and most especially, the
pocosins of the interior. Pocosins are isolated wetlands, which are
unique to the southeastern United States and concentrated in North
Carolina. The term comes from the Algonquin Indian words meaning,
"swamp on a hill" -- related to the fact that are often higher than
the surrounding terrain. Pocosins normally develop in blocked fossil
drainage areas, and are nutrient poor, receiving all of their
nutrients from the sky. Soils vary, but often consist of deep
organic soils called "peat," which develop because of the slow rate
of decomposition of organic matter in flooded soils. Deep peats
often contain "fossil" cedar, cypress, and heart pine logs as
evidence of their previous vegetative state (Rader, 1989). The
factors responsible for deep organic accumulation are high rainfall,
flat topography, large distances between streams, and shallow depth
to impermeable layers. During pocosin development, this caused
ponding, anaerobic conditions, and accumulation of organic debris
that further impeded water flow and enhanced the process of swamp
development. These deposits characteristically occur at elevations
higher than the surrounding mineral soils. Their only source of
water is rainfall, either directly or as lateral flow. Measurements
elsewhere in the region have established that peat formation last
began about 8900 (plus or minus 160) years B. P. (Oaks, 1964). The
highest point in the pocosin is near the Washington, Hyde County
line south of Lake Phelps.
Pocosin vegetation is also unique, consisting of broad-leaved and
mostly evergreen shrubs including titi, red bay, sweet bay, wax
myrtle, gallberry and zenobia. These shrubs are usually accompanied
by a thin overstory of pond pine. Pocosins are often made almost
impenetrable by an interlacing of green briar. In general, pocosins
are classified as "scrub-shrub bogs."
Pocosins and related vegetation types are maintained by three
factors: soil saturation with water, depth of the organic soil, and
frequency of fire (Otte, 1981). In deep peats with infrequent fires,
Atlantic white cedar may dominate, in almost monotypic stands.
Atlantic white cedar is highly prized by the forest product
industry, and was heavily utilized by the Roper Lumber Company for
the production of lath, shingles, and other products. Relatively few
stands remain intact, but at one time, there were thousands of acres
of Atlantic White Cedar in Washington County.
Pocosin vegetation burns fiercely once ignited, and peat fires may
burn for months underground. Small, frequent fires help maintain the
pocosin vegetation but large, infrequent fires can be extremely
destructive because some or all of the organic soil may be consumed
as well as the surface vegetation. Pocosin fires have occurred many
times over the years, and the present depth of the organic deposits
in Washington County is undoubtedly much less than in years past.
The Pettigrew papers contain accounts of fierce fires burning for
many days south of Lake Phelps (Lemmon, 1971, 1988). In some cases,
fire, drainage, and cultivation have resulted in the loss of the
entire organic surface. Dolman and Buol (1967) estimated that the
farmed land just east of Railroadbed Road (North Slope area) had
lost about 70 inches of organic surface. Aside from fire, all
drained organic soils will inevitably lose organic matter and
subside over time.
The most recent large destructive fire occurred in the spring of
1985 (the Allen Road fire) when over 100,000 acres of land burned in
three counties. On average, that fire removed 6-12 inches of organic
surface from the pocosin south of Lake Phelps.
The Blackland agricultural area of Washington County was once
covered by pocosins and other wetlands. Sites without deep peat were
converted for agricultural and silvicultural use, starting in early
historical times and proceeding until the early 1980's. Dense
drainage systems are necessary for successful farming in most former
pocosins (Lilly, 1981a). It has been estimated that Washington
County originally had about 180,000 acres of wetlands (Rader, 1989),
out of a total area of about 215,000 acres (about 84% of the land
area). The estimated acreage in 1982 from the National Wetland
Inventory was 58,704 acres remaining, much of it highly modified for
forestry production and other uses. It should be obvious that the
history of the county includes a heavy emphasis on drainage, and
that wetland issues continue to be of great importance to the
county. Summaries of the history of the development of North
Carolina pocosins are presented by Lilly (1981b) and McMullen
(1984).