Plans for replacing a defective bridge over the Congaree River in central South Carolina call for rebuilding several miles of causeways on the flood plain within Congaree National Park. Critics of the plan have sued to block the project, arguing that modifications are needed to preserve wetlands, remove existing impediments to water flow and wildlife movement, and improve access to the national park.
The 601 Bridge
US Highway 601 traverses the state of South Carolina from north to south, extending from near the North Carolina border almost to Savannah, Georgia. At about the midway point it crosses the Congaree River on a bridge that was built in the 1940s. Locals call this aged span the "601 bridge."
The bridge's northern approach, which crosses a four-mile wide flood plain, was constructed in the form of a series of causeways separated by three small bridges spanning small water bodies, including two arms of the river's largest oxbow lake. The highway construction standards of the 1940s emphasized cost savings and accorded little importance to environmental protection. Building culvert-equipped earthen causeways across a wide floodplain is considerably cheaper than constructing elevated bridging, so it didn't matter that the causeway caused considerable environmental damage.
The Trouble With Causeways
Causeways built on a floodplain are environmentally harmful in a number of ways. Acres of wetlands are filled or seriously degraded. Since the causeways must be built tall enough to keep the road bed perched above the reach of floodwaters, they act like a dam in some respects, impeding and diverting the natural flow of water, sediment, and nutrients. High embankments impede the movement of deer, squirrels, turtles, and other wildlife, which must also take their chances with highway traffic.
This Isn't the 1940s
Although none of these impacts was given much thought when the US 601 bridge on the Congaree was built back in the 1940s, they now loom very large. Highway construction projects are now subject to federal regulation that includes provisions for protecting wetlands like those of the Congaree River floodplain. Even more importantly, the floodplain land on which the causeway sits is now part of Congaree National Park. The park, which was established in 1976 (as Congaree Swamp National Monument), grew through additions that extended its boundaries well to the east, engulfing the US 601 bridge's northern approach.
The passage of the decades has not been kind to the 601 bridge. It's in such terrible shape now that it is quite literally crumbling. (Signs posted beneath it warn of possible falling concrete.) Continued use of the bridge threatens public safety and invites weight restrictions that could severely restrict commercial trucking on US 601, which connects with busy I-20 and I-26. The bridge has moved all the way up to fifth on a state list of priorities for replacement.
Everyone agrees that the bridge needs to be replaced, and very soon. However, not everyone agrees on what should be done with the northern approach (aka "601 corridor"), which must also be upgraded. The Federal Highway Administration-endorsed design that the South Carolina Department of Transportation (SCDOT) favors for the project would upgrade the 601 corridor on the floodplain by essentially rebuilding the causeway system currently in use. SCDOT claims that this is the only way to keep the construction costs (currently budgeted at $40 million) within reason.
The National Park Service, some other resource agencies, and several environmental groups have strongly objected to the SCDOT plan for the 601 corridor, insisting that it should be redesigned for minimal environmental disruption and better access to the national park. This would require replacing portions of the earthen causeways with elevated bridging, installing larger culverts, and making some modifications to enhance public use and enjoyment of the park. These changes would significantly increase the cost of the project. SCDOT has claimed, in fact, that a redesign of the 601 corridor to accommodate the proposed modifications could double the cost of the project.
Congaree National Park superintendent Tracy Swartout has been involved with the 601 bridge replacement dispute ever since she assumed her post in 2006. "By 2005," she said, "the shortcomings of DOT's 601 corridor design were already a matter of deep concern to the three resource agencies involved [the National Park Service (NPS), the US Fish and Wildlife Service (FWS), and the South Carolina Department of Natural Resources (SCDNR)]". "All three agencies," she said, " agreed that modifications would be necessary to improve the hydrologic flow across the US 601 corridor, protect adjacent floodplain resources and values, and enhance wildlife passage across the project area."
This was not just a wish list. Project modifications producing these results would be needed to comply with FWS and NPS mandates and to adhere to NPS management policies for adjacent park lands.
Note: For convenience, the four bridges involved in the 601 bridge replacement project are coded as follows: bridge #1 is the northernmost bridge (near St. Luke AME Church); #2 spans the northern arm of the U-shaped oxbow lake called Bates Old River; #3 spans the southern portion of Bates Old River; and #4 is the large bridge that crosses the Congaree River.
The resource agencies have jointly recommended these project modifications since 2005:
(1) Remove the existing roadway embankment between bridge 3 and 4 and replace completely with elevated bridge spans.
(2) Install three natural bottom culverts (8’ x 24’) between bridge 2 and 3.
(3) Extend existing bridge 2 span by approximately 500 feet along the upland side of Bates Old River.
The three basic modifications that the resource agencies have been insisting on are not the only changes that critics of the SCDOT plan would like to see. Superintendent Swartout says that some additional modifications are needed to address the park's ecological concerns and the need for improved public access.
The park is concerned about the floodplain hydrology, quality, quantity and sheet flow of the water in the wetlands adjacent to and in the park. It is also concerned about the direct and indirect damage the project will inflict upon the wetlands. This concern was manifested by the sacrifice of high quality wetlands for marginal wetlands with the placement of construction upon highly functioning wetlands rather than upon already damaged wetlands. Following the ecological concerns are our concerns with visitor access.
To address these issues, the park in late 2007 and early 2008 suggested these additional modifications:
(1) Installation of three natural bottom culverts between bridges 2 and 3. Ideally these would be 8' x 24'. (SCDOT stated that when a culvert exceeds 20' certain engineering problems arise. This in part may explain why SCDOT proposed 5' culverts. While the Park recognizes that this is a step in the right direction, reality is that such small culverts create a multitude of other problems. The park would find a culvert, of 18' to 20' sufficient to address these problems.)
(2) Removal of the roadway embankment between bridges 3 and 4 and replacement of the embankment with three elevated bridge spans. The Park also suggested extension the span for bridge 2 by approximately 500 feet along the upland side of Bates Old River. (SCDOT has stated that this would be quite expensive and is beyond the proposed budget for the project. While the Park acknowledges that this could be expensive initially, the long term ecological benefit could outweigh the short term cost.)
(3) Moving the proposed DNR boat landing east of Highway 601 (downstream), to an area that has already been damaged, rather than locating it upstream, west of the highway. This would preserve some higher quality wetlands.
(4) Revision of the highway design to include paved pull outs with parking spaces constructed parallel to the highway in areas that have already been ecologically damaged. This would provide safe scenic overlooks for park visitors (and future trailheads) and wildlife viewing for the public while not sacrificing quality wetlands.
(5) Changing the design of the exit ramps to the Fork Swamp tract which is east of the project, to improve the safety of egress from and ingress to the highway.
The original environmental assessment (EA) of the project, dated March 2005, included project alternative and environmental impact discussions that ran to a grand total of just ten pages. After SCDOT decided to proceed with the project without making modifications recommended by the plan's critics,several NGOs opposed to the plan filed suit. In 2008 they won a court decision that forced the Federal Highway Administration to do a more thorough environmental assessment.
The new EA proved very disappointing. The three environmental groups spearheading opposition to the SCDOT plan -- Friends of Congaree Swamp, the South Carolina Wildlife Federation, and the National Audubon Society -- filed a second lawsuit in September 2010 after concluding that the Highway Administration's revised EA was little more than a rehash of the first one. The plaintiffs claim that the revised EA fails to satisfy National Environmental Policy Act (NEPA) requirements, pointing out that the document contains scant discussion of how the project will impact the ecology of the 27,000-acre national park. Congaree National Park protects the largest remaining tract of old-growth riverbottom hardwood forest in the U.S. and has trees so large that the tract has been called "Redwoods East."
Critics of the SCDOT plan are now demanding that the revised EA be thrown out, and that the bridge project be halted until a rigorous environmental impact assessment can be completed. The lawsuit filed in September is still pending in federal court, with a decision expected next spring.
With public safety hanging in the balance, replacing the defective US 601 bridge over the Congaree River is an urgent need. The parties to this dispute have accordingly reached an interim agreement that allows work on the river span to go forward while the floodplain wetlands are protected from further construction damage.
Visit this Friends of Congaree Swamp website for more details about this issue and to see a copy of the revised environmental assessment at issue in the pending lawsuit.
Facilitating Public Recreation
Although protecting vital natural resources remains their primary concern, critics of the SCDOT plan for the 601 corridor are also very disappointed with the plan's lack of regard for public access to the park and the Congaree River. As the Friends of Congaree Swamp point out, these opportunities include:
• Boating activities on Bates Old River. Bates Old River is actually a placid 2-mile-long oxbow lake immediately accessible from the 601 embankment. Boating trips along the lake would provide visitors with opportunities to study alligators, large wading birds and raptors such as osprey and Mississippi kite.
• Hikes to the Congaree River. The river can be reached from the 601 embankment by a modest hike (2.5 miles round trip) along the route originally traced by historic Bates Ferry Road. A giant cypress is easily accessible along this trail; two stumps of other giants stand nearby. Though other ancient cypress can be found in remote sections of the park, no similar cypress can be as readily visited from the park's existing 25 miles of trails. At the site of the former Bates Ferry Bridge, a clearing provides opportunities for picnicking on the river and interpretation of this historic landing.
• Boating access to the Congaree River from the Department of Natural Resources' 601 boat landing. The park (with the assistance of Friends of Congaree Swamp) recently purchased a 16-passenger boat for interpretive trips and resource management along the river. Though the boat landing is currently neglected, if improvements are made, trips along the river represent a new and exciting mission for the park.
• Interpretive pull-outs along U.S. 601. U.S. 601 bisects the impressive ridge-and-swale system created by the great bend of the Congaree before it was cut off by a flood in 1852. In addition to their interest as floodplain features, these swales and ridges serve as wildlife corridors, and the swales often harbor interesting wildlife. Interpretive opportunities for the park along the 601 corridor would be entirely new and complement those already available through the park's Harry Hampton Visitor Center near Hopkins.
Current SCDOT plans for the 601 corridor mention none of these opportunities and make no provision for public activities in this portion of Congaree National Park.
In particular, there are no plans to accommodate interpretive pull-outs, parking for trailheads, improvements for future boating access, etc. To date, both the state and federal highway agencies have taken a narrow view of the 601 bridges project, from both the natural resource and recreation resource perspectives, rather than the expansive view that such an important and unique resource requires. South Carolina's residents deserve the opportunity to have plans for the park become part of the dialogue on development and restoration of the 601 corridor.
These additional contentious issues have been been pushed to the background in the bitter struggle over the 601 corridor redesign, but they deserve more emphasis. There is, after all, only one Congaree National Park, and this will be the only chance in a very long while to build a 601 corridor that enhances public access to it.