Dredge Barge (IMAGE) Penn State Caption Immense barges bearing huge shovels have scooped gravel out the Allegheny's pools 7 and 8 for decades. Credit Jonathan Freedman Usage Restrictions non commercial use only 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.