Linnwood to Riverside Tunnel Inspection

Posted By: Mark Mutziger ACEC WI News, Awards,

2024 Engineering Excellence State Finalist

Entering Firm: Collins Engineers Inc.
Client: Milwaukee Water Works

Milwaukee Water Works, responsible for supplying clean water to over 867,000 residents, faced a critical inspection challenge with a 7,100-foot transmission tunnel. This inspection is required every seven years and looks for defects or damage that could affect service and water quality. Traditionally inspected through divers or dewatering, the process was costly, time-consuming, and disrupted operations significantly.

Collins Engineers implemented an innovative approach, using the SUNFISH® autonomous underwater vehicle (AUV). Collins provided a dive team to guide the AUV through the tunnel, set up pulley systems and assist with calibration and retrieval.

The AUV inspection was a remarkable success, completing in four days with nightly service restoration, minimizing disruption to water supply operations. The inspection was accomplished in only 4% of the time and at 40% of the cost compared to the previous dewatered inspection. The tunnel, crucial for water supply, was found to be in generally good condition with no significant defects.

The design team’s quick thinking delivered an amazing solution. The client saved money and time while ensuring the continued exceptional service for nearly a million residents.

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