High Water Table, Wetlands Causing Flooding At Cape Hatteras National Seashore
Wet weather this fall has created a problem of standing water at Cape Hatteras National Seashore, where officials say a high water table is responsible. Quick solutions, though, are not readily available, as various state and federal laws prevent the park from simply draining the water away.
While the national seashore has a drainage ditch system, it was built "decades ago before the Wetlands Protection Act and other modern environmental laws came into existence," says Cyndy Holda, the seashore's spokeswoman.
"The ditches were meant to reduce water levels in and around Cape Point Campground, which was built in a wetland, but ironically the drainage system had no fixed outlet, so the system holds water rather than drains it."
In years past, she says, the seashore staff would use heavy equipment to trench ditches to drain the water from wetlands areas and roads to the beach. However, when crews did that in 2004 the North Carolina Division of Water Quality issued a Notice of Violation to the seashore for violating state laws that prohibit draining wetlands, the spokeswoman added.
"The NPS has studied the issue for several years, and there are no easy fixes (such as cutting a "drain" any time high water occurs) that would be legal or appropriate," Ms. Holda said. "An NPS hydrologist and a wetland ecologist have visited the area since 2004 and written technical reports stating that the 2004 action not only violates state and federal law, it also violates NPS policy. Their assessment is that the area floods because of an elevated water table; in essence, the water table is 'above ground level' wherever there is standing water, which occurs over an extremely large area.
"The most practical long-term solution, with proper planning and compliance, may be to raise the road and provide proper drainage underneath the road, particularly since flooding seems to be occurring more often in recent years," she said.
Areas impacted by heavy rains this fall (after Hurricane Irene) include the wetlands surrounding portions of Lighthouse Road near the Cape Point Campground and beach Ramp 44. A section of the eastern end of the road several hundred yards long has been under 6-12 inches of standing water for weeks, said Ms. Holda.
"ORVs have generally been able to drive through the water to reach Ramp 44, which for the most part has remained dry. Though not as convenient as Ramp 44, ORVs have also had reliable access to Cape Point from Ramp 49," she said. "We realize that some people would prefer that we simply cut a ditch (the "drain") to the ocean, like in the old days, to lower the water level across a large wetland area enough to reduce the standing water on the road; however, as stated previously, that would violate laws and policy and would not be appropriate in a unit of the national park system."
This coming winter the seashore staff plans to begin work on an environmental assessment that would evaluate the impacts of proposed infrastructure improvements. That document is expected to look at the options for addressing "the flood-prone eastern portion of Lighthouse Road," said Ms. Holda.