Abstract : Acoustic Doppler Current Profilers are presently employed by the U.S. Army in a number of projects. However, as with most new techniques there have been several problems both with the collection and the subsequent analysis of data. The main objective of this work is to improve the accuracy of Acoustic Doppler Current Profilers by examining the existing survey techniques and by developing computer software to process survey data. Two FORTRAN programs have been developed during the contract period. One program is designed to combine data from an external differential global positioning system with data from an ADCP to give a more reliable discharge measurement, and the second program is designed to in-fill gaps in records due to missing ADCP velocity data. In order to test and develop the software, data was collected on the Columbia River, Washington. This document details the resulting software designed and briefly reports on the fieldwork undertaken.