Abstract : This technical note describes the Tons Dry Solids (TDS) measurement method and summarizes the initial experiences of the U.S. Army Corps of Engineers with its use on Corps and contractor hopper dredges. Subsequent technical notes will describe further TDS measurement developments that evolve from these experiences. 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.