Orion Marine Group Inc. has been working to deepen and widen navigation channels and berthing areas for the Port of Houston Authority (PHA). PHA awarded the $69.8 million contract in 2014 to dredge the Bayport Ship Channel and the Barbours Cut Channel deepening them by five feet and widening some areas. The project will remove an estimated 6.6 million cubic yards of native and shoaled sediments and PHA expects the project to be complete by mid-February 2016.
The project is 100 percent PHA funded and the initial planning began in 2010. The first permit application was submitted in November 2011 and the permits for both channels were granted in April 2014.
Half of the estimated 6.6 million cubic yards of material dredged will be used beneficially. Here excavators work with material placed on Atkinson Island eventually raising the current dike elevation by five feet.
David Casebeer project manager at the Port of Houston Authority said PHA worked out a program with the Corps of Engineers using a section 214 agreement (WRDA 2000) which allowed for expedited permitting (CWA 404 & RHA 10) engineering approval (408 report) and the Assumption of Maintenance (204) report.
“This allowed us to accomplish everything in a couple of years instead of the normal process that could take a decade or more under the normal federal process” Casebeer said.
The Notice to Proceed for the dredging of Barbours Cut Channel was issued in July 2014 and Orion has been on-site to prepare the dredge material placement areas since May 2014. Dredging in the Barbours Cut Channel began in July 2014 and is expected to be completed in late June 2015. In November 2014 dredging at Bayport Ship Channel began and should be completed by mid-February 2016. Dredging at the Bayport Container Terminal berths began April 11 and should be completed by mid-August 2015.
The two channels were originally private channels. In the mid-90s the Corps assumed maintenance of the channels. After PHA completes the current work in the channels the maintenance moving forward will again fall to the Corps. This will require PHA to do the first maintenance dredging just after the initial work before handing over the channels to the Corps for maintenance in perfect condition.
The improvements to the channel will increase the maintenance requirements slightly Casebeer said. However that additional cost is far outweighed by the economic benefit of the larger ships that will have access to the two channels he added.
The channels and berthing areas will be deepened to an authorized depth of 45 feet (Mean Low Tide) to match the main Houston Ship Channel which was deepened in 2005.
At Barbours Cut Channel the berthing area is being expanded from 150 feet wide to 225 feet which required the ship channel to be shifted 75 feet to the north to maintain its current width of 300 feet. The channel and berthing areas are also being deepened to from an authorized depth of 40 to 45 feet (Mean Low Tide). Orion will dredge approximately 587000 cubic yards of new sediment from the channel; 572000 cubic yards of maintenance material; and 183500 cubic yards of sediment from the berthing area.
At Bayport Ship Channel the dredging will deepen the channel from an authorized depth of 40 feet to 45 feet (Mean Low Tide) and widen the channel 100 feet to the north in the open bay reach then transition from a 100-foot widening to 50 feet inside the land cut. Orion will dredge an estimated 3.87 million cubic yards of undisturbed native sediment and 1.38 million cubic yards of shoaled sediment.
Orion is using three dredges – two diesel and one electric dredge. The 24-inch cutter suction dredge Richard LeQuay is working in the Barbour Cut Channel and berth areas.
The dredge Linda LaQuay a 24-inch diesel cutter suction dredge is working in the Bayport Ship Channel. The dredge has a 40-foot by 227-foot dredge hull and a 100-foot ladder.
The electric dredge Waymon Boyd a 20-inch cutter suction dredge is working around the docks at Bayport Container Terminal. The dredge has a 34-foot by 150-foot dredge hull and an 88-foot ladder.
Casebeer said using an electric dredge specifically was not a requirement but there were sound requirements for work close to the residential communities. Also when working in the Bayport Container Terminal docks portion the contractor must stay below the nitrous oxide emissions limits set by the permit which is a tall order for diesel dredges of this size Casebeer said and the electric made it easier.
The project includes mitigation for oyster habitat impacted in the Bayport Ship Channel – 4.63 acres of reef restoration at Fisher’s Reef incorporating 13000 tons of crushed limestone which was completed in December 2014. For the wetland mitigation where 9.52 acres of salt marsh was impacted PHA purchased credits from the Gulf Coastal Plains Wetland Mitigation Bank.
half of the material dredged from the channel will be used beneficially. From the Barbours Cut Channel the new work clay will not be used to raise the containment dike at Spilmans Island during this contract but the clay is being disposed of in an adjacent berm where it can be used in a future federal project to raise the containment dike. From the Bayport Ship Channel approximately 2.4 million cubic yards of new work clay will end up in the template of the new containment dikes. This material will allow a lift of five feet over the current dike elevation leaving approximately six million cubic yards of capacity after the current project.