Howard County Pilots Condition Assessment Technology for Critical Metallic Mains

Seventeen years ago, Howard County piloted one of the first acoustic systems for monitoring the changing condition of prestressed concrete cylinder pipelines in the country. Over the years they have invested and benefited as an early adopter to various condition assessment technologies and techniques for the proactive management of their water and wastewater systems. The Howard County Department of Public Works Bureau of Engineering provides water and wastewater services to more than 260,000 people with an average demand of more than 26 million gallons of water each day. The water system is comprised of more than 1,000 miles of pipelines, approximately 90% of which are metallic. Understanding the condition of critical large-diameter mains helps Howard County proactively reduce water main breaks while more efficiently planning capital replacement programs. Traditionally, Howard County has employed physical entry methods or tethered robotics techniques for inspections which can be logistically demanding and may require dewatering of the pipeline. In January 2018, Howard County began planning to pilot a free-swimming condition assessment technology on a 2-mile section of a 24-inch ductile iron and cast iron water main. The tool is designed to inspect the line while in-service, therefore reducing disruption of service, logistics, and the need for dewatering. This paper will summarize the planning phase of the pilot inspection, providing an overview of the issues needing to be addressed prior to performing an internal inspection of an in-service transmission main using a free-swimming technology platform.