Proposed Guide Wall at the Dalles Dam (IMAGE) DOE/Pacific Northwest National Laboratory Caption A computer-generated image shows how the proposed construction of a guide wall downstream of the Dalles Dam would alter the water's direction on the Columbia River. Credit Pacific Northwest National Laboratory Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.