SUMMARY - doeri20013

ERDC TN-DOER-I2

July 2000

Physical documentation of the calibration procedures and corresponding printed verification data

are required for every calibration event.

SUMMARY: A DOER Program work unit is currently investigating the applicability of TDS

measurement for Corps dredge contract payment purposes. TDS determines the amount of dry

solids in the hopper. It was originally developed in The Netherlands where its use in silty material

has been determined to be a basis for fair and accurate measurement of payable dredged quantities.

It has also provided an incentive for the contractor to improve performance.

The work unit is presently focused on collecting the data for calculating TDS and establishing the

accuracy and reliability of those calculations. Items receiving special attention include the following:

Instrumentation and equipment requirements.

Minimum accuracy requirements.

Quality assurance and control procedures.

TDS data acquisition and database management within the SI system.

In the future, the focus will shift to analyzing the TDS database and investigating the use of TDS

for various geotechnical and hydrodynamic settings.

In order for TDS to be successfully implemented, the dry ton (as a payment unit) and the manner

in which it is determined must be understood by and agreeable to both contract parties. Corps and

contractor understanding of TDS as a payment method will increase as more TDS data are collected,

allowing better correlations between TDS and dredging costs and project volumes. Because TDS

is a method that measures in conveyance, its data can also be used for contract management,

production feedback, and mass balance purposes.

POINTS OF CONTACT: For additional information on TDS measurement or the Silent Inspector

System, contact the authors of this technical note, Mr. James Rosati (601-624-2022, rosatij@

wes.army.mil) and Mr. Timothy Welp (601-634-2083, welpt@wes.army.mil) or the Program

Manager of the Dredging Operations and Environmental Research Pogram, Dr. Robert M. Engler

(601-634-3624, englerr@wes.army.mil). This technical note should be cited as follows:

Welp, T. L., and Rosati, J., III. (2000). "Initial Corps experience with Tons Dry Solid

(TDS) measurement," DOER Technical Notes Collection (ERDC TN-DOER-I2), U.S.

Army Engineer Research and Development Center, Vicksburg, MS.

www.wes.army.mil/el/dots/doer

REFERENCES

Alexander, M., Murphy, M., and Scott, S. (1996). "Innovative dredging operations monitoring for the Oakland

Deepening Project." Proceedings of the Western Dredging Association Seventeenth Technical Conference and

Twenty-Ninth Annual Texas A&M Dredging Seminar, New Orleans, June 11-14, 1996, 253-270.

Burke, L. (1989). "Logging system developed to monitor hopper dredges," International Dredging Review

November/December, 8-9.