Click here to watch the dive in action: Deep Dive Boat

Pickering, Corts and Summerson, Inc. (PCS) recently completed deep diving inspections of the S.R. 0059 crossing of the Allegheny Reservoir in northwestern Pennsylvania.  The reservoir, located within the Allegheny National Forest, is a well-known destination for outdoor recreation. The bridge traverses a significant section of the reservoir where water depths at the piers range from approximately 70 feet during seasonal drawdowns to more than 100 feet when the reservoir is at full pool elevation.

To optimize both safety and efficiency, diving inspections are conducted during the fall season, after the summer recreation period and during drawdown conditions.  At this time water levels are reduced below the 100-foot threshold established by OSHA and ADCI requirements for mandatory on-site recompression chamber support. Maintaining dive depths below this limit results in substantial savings in mobilization costs, logistical effort, and overall project duration. Fall conditions also provide favorable environmental factors for diving operations. Water temperatures remain relatively comfortable from residual summer warming, contributing to improved diver endurance and overall operational efficiency.

The inspections were performed using Surface Supplied Air diving equipment and procedures along with wrist-worn diving computers running the latest decompression algorithms. This allowed each diver to maximize available bottom time for the inspection through continuous monitoring of depth, ascent rates, and decompression status throughout each of the 90′ dives completed at the site.

PCS was able to use careful planning and efficient execution to perform thorough underwater assessments to document the condition of submerged structural components while conducting a safe, cost-effective, and efficient inspection in one of Pennsylvania’s most unique and environmentally significant bridge settings.