TripReportCapeHatteras_11-15 to11-17 2005

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United States Department of the Interior
0
NATIONAL PARK SERVICE
Water Resources Division TAKE PRIDE'
C 1201 Oakridge Drive, Suite 250 IN AMFRICA
Fort Collins, Colorado 80525-5596
F.
IN REPLY RDTA TO:
December 23, 2005
L54(2380)
CAHA/Gencral
Memorandum
To: Superintendent, Cape Hatteras National Seashore
Through: William L. Jackson, Chief, Water Resources Division (W -RD)
Gary Rosenlieb, Acting Chief, Water Operations Branch, WR -
From: Larry Martin, Hydrogeologist, Water Operations Branch, WRD FV
Subject: Trip Report for travel to Cape Hatteras National Seashore, November 15-17, 2005
Recommendations for reducing flooding in the vicinity of Cape Hatteras
Summary: One of the NPS management objectives in the Cape Point area is reducing flooding
of the campground and interdunal roads while minimizing the hydrologic disturbance to adjacent
wetland areas. Multiple ORV access routes through the interdunal area are desired to reduce
conflicts between ORV use and beach closures for resource protection. The only actions which
will provide more reliable ORV access to the beaches are rerouting or raising the roads to an
elevation higher than the normal high-water levels or construction of a drainage ditch to
effectuate flow of standing water from the interdunal area to the ocean. Drainage ofwater would
cause adverse impacts to wetlands and would be contrary to North Carolina state law. It would
also be contraryto NPS management policies.
The hydrology of the Cape Point area has been Ughly manipulated by construction of drainage
ditches, excavation of sand for beach nourishment resulting in formation of ponds, and
construction of artificial dunes. The area is very dynamic; undergoing rapid geomorphic change
with every nor'easter and hurricane. Rising sea level will likely hasten the rate of geomorphic
change in the next few decades. These geomorphic changes may make maintenance of the
campground and beach access roads through the interdunal area a moot issue within a few years
or decades.
Discussion: Providing ORV access to the beaches at Cape Hatteras has been an issue for several
years. The problem is exacerbated by closure of some areas of the beach for resource protection
(terns, piping plovers, turtle nests) and flooding of some of the beach access roads. Beach -
closures and flooded access roads can, separately or in combination, result in limiting access to
large areas of the beach and leads to conflicts between visitor access and resource protection.

The park desires to have multiple ORV access routes through the interdunal areas to the beach.
ORV access is less restricted with multiple access routes if it is necessary to close sections of the
beach for resource protection.
There, is a network of drainage ditches around the campground and along the road south of the
lighthouse toward the Cape. In the past, when the area flooded, the headgate west of the
campground would be opened and water would drain through a 3 ) 6 -inch culvert under the dunes
(Figure 1). A drainage ditch from the outfall of the culvert to the ocean would be dug to speed
the drainage. When the water level in the campground and along the roads had receded, the
headgate would be closed and the action of waves would quickly fill the drainage ditch on the
beach face.
Figure 1. Major drainage ditches in the vicinity of the Cape Point Campground.
When the headgate is open, water is drained from a large area of freshwater wetlands north and
west of the campground. Additionally, when a ditch is opened to allow discharge to the ocean,
water is drained from marine wetlands in the interdunal area south of the campground.
2

After Hurricane Isabel in September 2003, the park opened two additional drainage ditches on
the east -facing beach south of the lighthouse and north of Ramp 43 to alleviate flooding. The
park also opened the Aeadgate west of the campground and opened a drainage ditch from the
outfall of the culvert to the ocean on the south beach. Following a complaint from the North
Carolina Coastal Federation, the two drainage ditches on the cast -facing beach were closed. The
drainage ditch west of the campground continued discharging to the ocean on the south -facing
beach. In April of 2004, officials from the North Carolina Division of Water Quality and the
U.S. Army Corps of Engineers visited the area and reviewed the drainage ditch system with park
staff. The park was subsequently issued a Notice of Violation for draining of wetlands. Park
staff closed the headgate and placed sandbags against the headgate to limit the flow of water
from the drainage ditches to the interdunal area and the ocean. Wave action on the south beach
has completely filled the drainage ditch across the beach face.
Since the closure of the drainage ditch, interdunal roads south of the campground have been
flooded almost constantly. Flooding is a result of high water levels in the low-lying areas. Flow
of water out of the area (in the absence of the ditch across the beach face) is controlled by the rate
at which the water can percolate through the sand dunes and beach sand and flow toward the
ocean as groundwater. Because the flooded areas are only a few feet above sea level, the
gradient, and therefore the rate of groundwater flow, is very low. The problem is further
exacerbated by ponding of water in the areas north and west of the, campground that were
previously drained by the ditches. With water levels in these areas now maintained at higher
levels, it becomes a nearly constant source of groundwater flowing from the interior parts of the
island toward the ocean. Higher groundwater levels in the interior part of the island cause
groundwater levels in the interdunal area to be higher, causing flooding in the [ow -lying areas.
Under the current conditions (with the headgate closed) the interdunal roads (Salt Pond Road,
Ramp 45, and Culvert Ditch Road) will remain flooded nearly all of the time as has occurred
during the past I V2 years as illustrated in Figure 2.
In the past, the headgate on the drainage ditches would be opened when flooding occurred and
the water levels would be quickly lowered to mimic dry conditions with lower water table
elevation and dry roads in the interdunal area. Since the headgate is no longer opened, high
water conditions persist much longer, with the result that the interdunal roads remain flooded for
long periods, The locations of interdunal roads and the general area where flooding is a problem
are shown on Figure 3, with a more detailed view of the area in Figure 4.
The only remedies to the flooding of the interdunal roads are to reroute the roads to a higher
elevation, raise the elevation of the roads above the typical water level, or to open a ditch to the
ocean to allow faster drainage and lower water levels in the interdunal area.

IM
10
LL
W
Water Table - Wet Conditions
Water Table - Dry Conditions
200 400 600 800 1000 1200 1400 1600 1800
1)[stanco From Ocean, Feet
Figure 2. Schematic South to North Cross Section in the vicinity
of the drainage ditch outfall and headgate, Fvest of the campground.
The feasibility of rerouting the access roads to higher elevations has not been thoroughly
investigated but appears problematic because most of the area is only a few feet above sea level
and is frequently flooded. Higher elevation routes to the beach are probably nonexistent.
However, it may be possible to -find a route having, only a few, short, low -elevation areas that
could be filled in to create more reliable access.
When the interdunal roads south of the campground are flooded, ORV access to the beaches is
generally finfited to the east -facing beach. There is generally no access to the south -facing beach
from the cast -facing beach- Outflow from the large pond usually creates an impassable barrier
around the southernmost tip of the cape.
Raising the elevation of the interdunal roads seems problematic in that it would require several
feet of fill on about two miles of road to make all of the roads usable. Fill material is in very
short supply on Hatteras Island. Building and maintaining elevated roads would be very
expensive. It might be possible to raise selected areas of the interdunal roads, for example Ramp
45, to provide better access in selected areas during high water conditions. Elevated roads may
be more susceptible to erosion during storms due to their exposure. Raising the elevation of
roads would almost certainly include widening the roads to achieve the desired elevation gain.
Placing fill in wetland areas to widen the roads would trigger wetland compliance review by the
National Park Service, Corps of Engineers, and the State of North Carolina.
4

Figure 3. Interdunal Roads and Beach Access in the Cape Point Area.
Constructing a drainage ditch from the pond at the outfall of the existing culvert to the ocean
would maintain dry roads through the interdunal area most of the time, There would still be
short periods when high water would cause the roads to be closed, but the duration and frequency
of flooding would be much less. The drainage system could be designed to remove water from
only the ii-iterdunal area, or to include drainage of the campground and adjacent areas. A pipe
could be buried across the beach face that would facilitate drainage of water from the flooded
areas without disrupting ORV access along the beach. Construction of a drainage ditch with
discharge to the ocean would result in artificial drainage of wetland areas and therefore be
contrary to regulations of the North Carolina Division of Water Quality and NPS management
policies.
5

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There has been no systematic water -quality monitoring of effluent discharged to the ocean during
periods when the ditch was flowing to the ocean. Preliminary results of current bacterial testing
of water in the drainage ditches in the vicinity of the campground indicates that enterococcus
bacteria are sometimes present in concentrations exceeding North Carolina standards for
swimming and shellfishing. If this water was discharged to the ocean, it would require posting
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advisory notices for swimming and shellfishing and possibly closing sections of the beach.
It would be nearly impossible to drain floodwaters from the campground and the paved road east
of the campground without also draining adjacent wetland areas. Sections of the drainage ditches
beyond the campground could be dammed to limit the area of drainage, but some wetland areas
would still be affected. In order for drainage to be effective, it would be necessary to discharge
water to the ocean. If water were merely drained from the campground area and discharged in
the interdunal area, interdunal roads would remain flooded most of the time.
Rising sea level also contributes to higher water levels in the interdunal area. As sea level rises,
the base level for groundwater discharge rises and water levels in the interdunal area, and
throughout the island, gets backed up to higher elevations,
Applicable Law and Polies
Draining of wetlands and subsequent altering of the natural hydrology of wetlands is a violation
of North Carolina Administrative Code 15A NCAC 0213.0231 (b) (5) (F); Wetland Standards:
which states:
(5) Hydrological conditions necessary to support the biological and
physical characteristics naturally present in wetlands shall be
protected to prevent adverse impacts on:
­ (F) Water levels or elevations
In September 2004, NPS was issued a Notice of Violation from the NC Division of Water
Quality for draining the wetland areas in the vicinity of the campground via the ditch system and
discharging the water to the ocean NC Division of Water Quality staff stated (phone
conversation with Kyle Barnes) that the permitting process for altering the hydrologic function of
the wetlands in the area would begin with NPS submitting a 'Preconstruction Notification." The
Division of Water Quality would coordinate review of the proposal with the U.S. Army Corps of
Engineers and 5 other state agencies along with public review and comment requirements
(including preparation of the EA and EIS) of the State Environmental Policy Act of 1971
(SEPA).
'fl-ic North Carolina Division of Coastal Management would review any proposal for draining
wetlands or discharge to the ocean for consistency with the State's coastal management program
(hM2://dcm2.enr.state.ne.us/Permits/consist.htm). It is likely that any proposal to drain wetlands
or discharge water to the ocean would result in a letter of "objection" from the Division of
Coastal Management.
NPS management policy states, "The Service will... avoid, whenever possible, the pollution of
park waters...'rhe Set -vice will: ... Take all necessary actions to maintain or restore the quality of
surface waters and ground waters within the parks consistent with the Clean Water Act and all
other applicable federal, state, and local laws and regulations..." (Section 4.6.3 Water Quality).

It seems pretty clear that point discharge of stormwater containing elevated concentrations of
bacteria to the ocean would be contrary to NPS management policies
With respect to wetlands, NPS management policy states that the Service will employ the
following sequence:
• Avoid adverse wetland impacts to the extent practicable;
• Minimize impacts that cannot be avoided; and
• Compensate for remaining unavoidable adverse wetland impacts by restoring wetlands
that have been previously destroyed or degraded.
Actions that have the potential to impact wetlands must be addressed in an EA or EIS. If the
preferred alternative will cause adverse impacts on wetlands, a statement of findings (SOF) must
be prepared and approved in accordance with Director's Order #77-1 and the DO 77-1
Procedural Manual (http://www.natu.re.nps.gov/wetlancYindex-pro.html). The SOF should
contain the reasons why the preferred alternative must be Located and designed such that it has
adverse impacts an wetlands, and why no non -wetland alternatives or those with fewer wetland
impacts were chosen. A discussion of the various factors and trade-offs considered in arriving at
this decision should be included. Required contents of the SOF are found in Section 5.3.E of the
Procedural Manual.
Conclusions:
1. Flooding of roads in the interdunal area is directly related to maintaining high water
levels in the interior part of the island, as directed by the NC Division of Water Quality to
preserve the hydrological conditions of wetlands.
2. Raising the road elevations in the interdunal area above the normal water level would
require large amounts of fill and could be susceptible to erosion during large storms.
Wetland compliance review by Park Service, Corps of Engineers, and the State of North
Carolina would be required.
3. Water levels in the interdunal area could be lowered by constructing a drain and
discharging water directly to the ocean, although this would be contrary to North Carolina
law and NPS management policies.
4. Preliminary data indicates that direct discharge to the ocean is a source of pollution and
might require closing of beaches and posting of shelf fishing and swimming advisories.
5. Rerouting the beach access roads to higher elevation areas could provide more reliable
ORV access to the beaches without dewatering wetlands or discharging contaminated
water to the ocean. The feasibility of rerouting the roads has not been fully explored.
If there, are any questions regarding this trip report, please call me at [phone].

References
Mallin, Michael A., Matthew R McIver, and Virginia L. Johnson, 2005, Cape Hatteras National
Seashore Water Resources Assessment Report. Phase L Center for Marine Science. University of
North Carolina Wilmington, Draft Report. 57 pp.
National Park Service Management Policies 2001, NPS D1416, December 2000,137 pp.
cc
CAHA — Mark Hardgrove, Charlie Sellars, Ron Clark, John Wescott
2303 — Cliff McCreedy
2360 — Julia Brunner, Rebecca Beavers
2380 — Joel Wagner, Kristen Keteles
5 010 — Linda York