Dioptra teamed with DOWL in Ketchikan, Alaska to perform an HDS survey on two dams in Ketchikan that date back to the 1920’s. One dam is a 40-foot high 200-foot long curved concrete dam and the other is a 1200-foot long earthen dam. Both dams have been monitored historically by traditional monitoring techniques using settlement monuments. DOWL asked Dioptra to perform an HDS scan on each of the dams as a baseline for future dam monitoring. These scans will allow the Engineers and City personnel to monitor the entire dam surface between the permanent monitoring rods.