River Restoration
The Cape Fear River
The Cape Fear River is naturally shallow. Old charts show the depth was 12 to 20 feet at the river mouth in Colonial times.
Starting in the nineteenth century, the channel has been deepened in a succession of dredging projects, reaching a depth of 38 feet in the 1970s. That was satisfactory for vessels calling at the Military Ocean Terminal at Sunny Point and for most commercial traffic. The most recent project was commenced in 2000, by the Wilmington District of the US Army Corps of Engineers. The channel to Wilmington was opened to 42 feet in 2004. This depth was chosen to accommodate the largest vessels able to navigate the Panama Canal, “Panamax” vessels with a draft of 39 feet.
This project had two negative effects:
(A) The increase in cross-section of the channel fostered an increase in tidal amplitude, which extended the high tide farther up the river–all the way to Lock and Dam No. 1 above Wilmington, and farther up the tidal creeks along the river. This impaired the ability of anadromous fish to reach fresh water to spawn, and resulted in loss of trees in the marshes along the upper reaches of the tidal creeks. At least two species of endemic freshwater animals, found nowhere else in the world, are on the verge of extinction because of river dredging
(B) The increase in width and depth of the channel between Bald Head island and Caswell Beach at the river mouth enlarged the “sediment sink” that captures sand naturally migrating along the beaches. This resulted in rapid erosion of beaches and constant need for replacement of sand on those beaches, and substantial annual expense for maintenance of the channel depth.
The project started in 2000 is not complete. The latest estimate of the cost to complete the project is now $384 million, and recent records of ship movements show that only about 100 deep-draft vessels–almost all container ships from Asia–call at Wilmington each year. About two a week.
Congress has mandated the US Army Corps of Engineers to devote more of its energy and resources to restoration projects. Restoring the Cape Fear River to a previous depth and natural balance should be one of those projects. However, the North Carolina State Ports Authority and the Wilmington District of the US Army Corps of Engineers are advancing plans to dredge the river even more to accommodate the next generation of vessels to pass through the Panama Canal after completion of new locks, planned for 2014. That project, an exercise in serial engineering to correct old problems exacerbated by the most recent dredging project, is estimated to cost over $45 million.
Click here for an analysis of the feasibility of further dredging on the Cape Fear River, concluding that because of the turns in the river larger ships cannot be accommodated no matter how much dredging is done. This study further concludes that other problems indicate that allowing the river to restore itself to a shallower depth should be considered. (New)
Appendix A Review of Corps of Engineers Section 905(b) Analysis
Appendix B Corps of Engineers Feasibility Studies
Click here for an analysis of the channel turns in the Cape Fear River by comparison to Corps of Engineers and international standards for channel turns. (Revised)
Click here for the business plan of the North Carolina State Ports Authority prepared by Moffatt & Nichol and delivered in February 2011, calling for dredging the Cape Fear River to a depth of 50 feet.
Click here for a report by the Wilmington District of the US Army Corps of Engineers, prepared in 2010 but not released, describing problems with the channel turn at Battery Island and shoaling of the ocean bar channel at Bald Head Island.
Click here for a report by the Wilmington District of the US Army Corps of Engineers, released in April 2011, recommending a feasibility study for a $41 million project to
1. widen the turning basin at Wilmington (which is already as wide as the river),
2. further dredge the channel turn at Battery Island (which several simulation studies have shown is too sharp to accommodate existing vessel traffic let alone larger ships), and
3. modify the ocean bar channel at Bald Head Island to address the navigation problems arising from shoaling by capture of sand from nearby beaches.
That feasibility study has been funded by the State and Federal governments, and proceeds under the usual veil of secrecy.
