Background - trchl04-30011

The U.S. Army Engineer Research and Development Center (ERDC) has

responsibility under the Innovative Technologies (IT) Focus Area of the

Dredging Operations and Environmental Research (DOER) Program to identify

and evaluate innovative dredging and dredged material management technolo-

gies. Under this program, ERDC works with USACE Division and District

Offices to plan, conduct, and evaluate field demonstrations of high potential

technologies. During FY01, the Lower Mississippi River Division (MVD) and

the New Orleans District (MVN) requested the DOER IT Program to partner in

the demonstration and evaluation of use of a flexible-discharge dustpan dredge in

the HOP area. Jointly, the USACE agencies developed a scope of work (SOW)

and specifications for the demonstration project. Additionally, the Louisiana

Department of Natural Resources (LDNR) teamed with the USACE in planning

and sponsoring the demonstration project. The LDNR provided a major portion

of project funding under the Coastal Wetlands Planning, Protection and

progid=448). CWPPRA was designed to produce restoration projects that create,

restore, protect, and enhance coastal wetlands in Louisiana. The MVN

Operations Division and the DOER Program provided additional funding.

The proposed project was considered an innovative application of existing

technology. It was decided that the demonstration should be conducted at the

head of Southwest Pass under as typical river and navigation conditions as

possible during spring when high water results in the greatest current velocities.

This site and time period would present the most difficult conditions to typically

be encountered in this area of the Mississippi River. There is a bend in the

channel at the head of Southwest Pass forcing vessel traffic to "crab" across the

channel to make the turn, thus requiring more of the channel width. (Crabbing is

a term used to describe the condition where the vessel's heading is different from

its actual course.) Shoals build up rapidly in this area, and significant sediment is

deposited along the inside of the bend. High current velocities put a strain on

anchors, cables, push boats, and discharge lines.

The objectives for the demonstration project were to:

a. Demonstrate safe navigation and dredging operations of the flexible-

discharge dustpan dredge on the Mississippi River in the HOP area.

b. Demonstrate sufficient production capability to dredge and place

material in a designated marsh construction site.

The first objective was of primary importance, and if it could not be met, the

project was to be terminated. The dustpan dredge had to be able to work safely

and effectively with no disruption or interference with, or hazard to, normal

vessel traffic. The second objective included collection of sufficient data to

support determination of the cost effectiveness of the technology. The State of

Louisiana prefers the beneficial use of dredged material to restore wetlands over

open-water disposal of the material.

The SOW detailed a number of project requirements to be met during the

demonstration:

Chapter 1

Introduction