Application of Dredge Monitoring Systems to Dredge Contract Administration Quality Assurance

ERDC TN-DOER-I3

July 2000

Application of Dredge Monitoring Systems

to Dredge Contract Administration

Quality Assurance

PURPOSE: Monitoring technology is available for providing dredge process data to dredge

contract administrators during the course of a dredging contract. The U.S. Army Corps of Engineers

(USACE) contracts out more than 80 percent of all dredging under their jurisdiction. Presently,

Corps District offices have taken on more of a contract administration role rather than a technical

"hands on" role for insuring that the nation's waterways remain open and are navigable. Although

Corps inspectors are generally aboard the contractor's dredge during the dredging, the contract

administrator does not have direct access to dredge process data for evaluating the contractor's

performance. This technical note describes dredge-monitoring systems designed to provide contract

administrators with dredge process data for evaluating dredge productivity, efficiency, and overall

performance.

BACKGROUND: Generally, there are two types of dredging contracts: a lease dredge contract,

and a yardage contract. Payment of the lease dredge contract is based on an estimation of the time

required to remove an estimated amount of sediment from the project area. The primary consid-

eration for the cost of this work is the production capability of the dredge plant in removing cubic

yards of in place material per hour, and the hourly cost of the plant. The contracting officer is

responsible for insuring that the contracting dredge operates efficiently and maintains a reasonable

production rate over the project duration to insure that the terms of the contract are met. Typically,

the progress of the contractor dredge is gauged by post-dredging surveys which indicate if the

channel has been cleared to project depth. Potential disputes arise between the contractor and the

Corps concerning the rate the work is performed, i.e., if the dredging extends past the time specified

in the contract for completion of the job. In some cases, changing site conditions, such as sediment

variations or adverse weather or project site conditions will affect the work performance rate. If

conditions are encountered that affect the ability of the contractor to perform as specified in the

contract the contracting officer should be aware of these conditions within a reasonable time to

adjust the terms of the contract, and prevent costly litigation. Additional monitoring tools are needed

by contract administrators to judge if the dredge is operating efficiently and maintaining a reasonable

production rate.

The cubic yard contract provides payment to the contractor based on pre- and post-dredging surveys.

In this contract, the dredge contractor is paid by the volume of material removed, with the price per

unit volume negotiated in the contract. This price reflects the contractor's operating costs as well

as the profit margin. The primary consideration for this type contract is the accuracy and

dependability of the pre- and post-dredging surveys. The pre-dredging survey provides an estimate

of the material to be removed. In river systems, the river bed is constantly moving and changing,

sometimes drastically affecting the shoaling rate. During the time elapsed between the pre-dredging

survey and the contract bid and award, significant shoaling can occur, thus the pre-dredge survey

will underestimate the amount of material to be removed. Also, if the post-dredge survey is not

performed in a timely manner, additional shoaling can occur, thus again underestimating the amount