International Dredging Review

International Dredging Review

Photos provided by Randall Hintz

This spring the New York District Corps of Engineers completed a bird habitat project on East Inlet Island in Long Island (New York) Intracoastal Waterway that has attracted hundreds of endangered terns which are nesting on the island.

The project began in 2002 when the New York District assembled a multi-agency team to create the habitat.
The Long Island Intracoastal Waterway is a 33.6-mile long channel inside the barrier islands on the Atlantic Coast of Long Island.

The six-foot-deep 100-foot-wide channel begins at Patchogue and continues east into Shinnecock Bay at the south end of the Shinnecock Canal which feeds into Great Peconic Bay off Long Island Sound. It connects on the west to the Great South Bay Channel an 18-mile-long channel that extends to the Fire Island Inlet opposite Brooklyn. A number of inlets provide access to the waterway from the Atlantic Ocean and it is primarily used for recreational boating and fishing.

The waterway is maintenance dredged every few years and the dredged sand has been placed on upland sites on the mainland and ocean barrier islands. In recent years development growth along the shoreline has eliminated this disposal option.

The Corps assembled a multi-agency team to think of disposal alternatives.

The team consists of the New York District Corps of Engineers the U.S. Fish and Wildlife Service the U.S. Coast Guard Region 1 of the New York State Department of Environmental Conservation the New York State Department of State the National Park Service (Fire Island National Seashore) and the Town of Brookhaven.

|!|After examining what other districts along the waterway were doing with their dredged sand the team decided to dredge ‘bite-size pieces’ of the channel so there is less to dispose of and to deposit these smaller portions of sand on an island to create a wildlife habitat for threatened and endangered bird species including least terns common terns piping plovers and roseate terns|!| said John Tavolaro acting chief Operations Division New York District USACE.

East Inlet Island a 30-acre island one-half mile off the Town of Moriches mainland was chosen to be the habitat location.

The project began in September 2002 and from October 2002 to January 2003 dredging contractor Inner Space Services a 100 percent woman-owned company dredged approximately five miles of the channel pumping dredged sand onto a 13-acre portion of the island said Jodi McDonald project manager for the New York District.

Inner Space used the 14 x 12-inch dredge Mardi Gras to pump 60000 cubic yards of material a maximum distance of 7500 feet according to Laurie Lee Mason company president and dredging project manager. The dredged sand was then re-graded to achieve the proper slope and texture preferred by nesting birds.

The habitat was designed to encourage the birds to nest on the island. The team made the island inviting by de-vegetating it and building nest boxes to replicate the habitat needs of these shorebirds. In addition they placed string fencing and interpretive signage reminding the public that the area is restricted from human use and developed a predator control program in the event land predators such as foxes and raccoons migrate to the site.
The birds colonize nest and breed on Long Island in the spring after spending the winter in the south.

In spring 2003 birds were spotted nesting on the island. However they were mostly seagulls not the terns that the habitat was created to attract. The reason for this was that the island’s ground was not suitable for them to nest. The ground was |!|clay-like|!| and not the sand that the birds need for nesting and not conducive to the growth of vegetation preferred by these birds.

|!|The appearance resembled the surface of the moon|!| said Randall Hintz chief Technical Support Section New York District USACE. |!|Sediment samples taken prior to dredging indicated that the material to be placed would be predominantly sand. Unfortunately as with any dredging project individual pockets of finer grain material can pop up during the dredging operation. Of the 60000 cubic yards of material dredged from the project about 7000 cubic yards of fine silty material was encountered|!| said Hintz. The fine material was in a three-acre area in depths from six inches to eight feet.

|!|If finer materials are encountered early in the project contractors can generally cover them with sandy material since there is no threat to nature from silty material. Unfortunately for East Inlet Island the finer materials were encountered late in the project and had to be left exposed on the surface|!| he said.

|!|Because the 2003 season was very wet the team was unable to work on the project that year as the ground needed to dry out before any work could be done. In early March 2004 the team saw a new nesting season on the horizon and the need for immediate action. A project delivery team was organized in the New York District to develop suitable alternatives to remediate the situation. The plan was to cover over the majority of the silty material with a layer of sand and to create trenches where the silt was deeper to allow the material to dry.

On March 3rd the multi-agency team approved of the Corps’ remediation plan which needed to be completed by April 1 prior to the return of the birds. On March 25 B + B Dredging a HUB Zone small business contractor was awarded the contract and had one week to cover the clay material with sand.

B+B hired Chesterfield Associates who mobilized a bulldozer and excavator to the island with their amphibious landing craft. They moved clean sand onto the mud that had been allowed to dry and tilled the deeper areas to expose the deeper wet material to the air.

The B+B crews began work on March 25 and were finished by Sunday March 28 three days ahead of schedule.

In April personnel from the Corps the U.S. Fish and Wildlife Service and the New York State Department of Environmental Conservation planted 1500 plugs of beach grass and 300 goldenrod plants on top of the now-sandy surface of the island.

|!|As an agency this has been a great experience for us. We recognize the delicate relationship that needs to be built with the resource agencies early on to not only define the specific areas that need to be dredged but also a better understanding of the nature of the material to be removed|!| Hintz said. |!|With the nature of dredging these situations are unavoidable.

The most significant lesson learned for us as an organization is to work with the resource agencies up front to develop remedies should a similar incident occur on another project. The goal is to create a win-win situation for everyone involved|!| he continued.

|!|This project is a success in that not only are the endangered bird species nesting on East Inlet Island but the obstacle we faced showed the partnering agencies that if we put our minds together we can really accomplish amazing things in a short period of time|!| said Hintz.