The United States Army Corps of Engineers New Orleans District in close coordination with its federal partners the State of Louisiana and the Shaw Environmental and Infrastructure Group directed a temporary halt to dredging operations in the littoral system of Reach E-4 near the Chandeleur Islands until additional pipeline is in place to allow dredging from the approved borrow site in Hewes Point.
“The littoral zone supports currents that carry sediment and organic material critical to the integrity of the natural barrier islands” stated New Orleans District Commander Col. Alvin Lee. “Dredging in this area could have long term effects on the viability of the Chandeleur Islands.”
This decision follows the expiration at midnight last night of a temporary request granted by the Corps that authorized the State to proceed with the first 2000 feet of Reach E4 using borrow from the littoral system. The June 13 2010 request allowed the state one week to temporarily dredge from the littoral system and then immediately backfill the area.
In determining the best course of action the New Orleans district and its federal partners carefully considered the following alternatives:
Option 1: Temporarily halt operations of the Dredge California and use its crew and vessels to move the additional 7000 feet of pipeline in place prior to initiating dredging operations. The estimated required time to move this additional dredging pipeline into place in order to effect dredging from the approved site in Hewes Point is 5-7 days after tomorrow. The dredge downtime is approximately 5-7 days. The reason the duration for this option is shorter that Option 2 is that the Dredge California crew would also be assembling the dredge pipeline simultaneously with the pipeline crew.
Option 2: Allow the Dredge California to continue dredging from the temporary dredging area for an additional 8-9 days while the additional 7000 feet of dredged pipeline is being assembled. The amount of additional material removed from the temporary dredging area would be approximately 800000-900000 cubic yards. The dredge downtime is approximately 1-2 days. This option assumes the single crew assembling the dredging pipeline.
“Scientists and engineers from the Corps of Engineers USGS and other federal resource agencies have shared concerns in allowing the continuation of dredging in the littoral system” stated New Orleans District Commander Col. Al Lee. “Among the concerns is that the removal of material in this area will create additional erosion issues and possible deterioration of the Chandeleur Islands.
Option 1 was selected because it provided no additional removal of sediment from the littoral zone while still allowing the flexibility needed to ensure the project is completed in a timely manner.
The New Orleans District will continue to work very closely with the State of Louisiana their contractor Shaw Environmental & Infrastructure Group and our Federal partners to ensure timely execution of this project.