• Significance: The dam is the best preserved example of the two remaining dams from a one-way slack water navigation system for carrying coal, lumber, and milled products down the Lehigh River.

Developed by Josiah White and patented in 1819, the Bear Trap Dam was a hydraulic lock. Water was allowed to flow into the chamber where it was trapped and channeled under the gates, causing the gates to rise and impede the river flow. As the water pooled, loaded wooden arks 85 feet long and 14 feet wide were positioned behind the dam, awaiting passage. When the pool was sufficient, the water in the chamber was released causing the gates to drop and create an artificial freshet which the arks rode downstream to the next lock or dam. At the end of the journey, the arks were dismantled and sold for lumber. The advent of the railroad and the seasonal flooding of the Lehigh River Valley during the mid-1800's brought the demise of slack water navigation and the Bear Trap Dam.

• Unprocessed Field note material exists for this structure: N1267
• Survey number: HAER PA-646
• Building/structure dates: ca. 1819 Initial Construction