Since Kingsport installed the new leak detection system, more than 116 distribution line leaks and breaks have been found and repaired.
Performance Contracting
Although implementing a water loss management system offers municipalities environmental, operational and energy cost savings, it’s often an expensive endeavor. To finance these improvements without raising taxes, issuing revenue bonds, or dipping into reserve funds, the City of Kingsport used performance contracting.
The budget-neutral strategy enabled the city to reduce its utility, operational and maintenance costs and its carbon footprint, while using the increase in billable usage and the reduction in operational and maintenance expenditures to fund the upgrades. The ESCO that implemented the water loss management program guarantees the benefits and will repay the city the difference for any benefits that have not been realized.
Over the course of the 17-year performance contract term, the AMR and leak detection systems are expected to generate more than $15 million in guaranteed benefits. Designed to reduce energy costs in public facilities, energy savings performance contracts with qualified ESCOs include engineering services, equipment installation and commissioning.
Leak Detection
To reduce its real water losses, Kingsport installed an automated leak detection system that identifies and prioritizes leaks within the distribution system for repairs without disrupting the municipality’s day-to-day activity. The system identifies leaks and breaks in pressurized water lines by measuring noise and vibration levels that radiate through pipes in the infrastructure. Measurements can be captured because some of the energy from the water is transformed into both an audible noise and a mechanical vibration.
Electronic leak sensors are permanently mounted on service lines upstream of the water meter. The sensors detect leaks by recording vibration frequencies each night between midnight and 4:30 a.m., when system pressure is at its peak, and usage and ambient noise levels are at a minimum.
Leak detection data is transmitted via radio frequency to a mobile collector, then uploaded onto a secure, customized website where it is analyzed by the system manufacturer. Once the data has been analyzed, the website displays a map of the city, labeled with colored balloons that represent the leak status of a particular sensor. A red balloon signifies a probable leak site, a yellow balloon denotes a possible leak site, and a green balloon indicates that no leak is present. This data can be exported into a spreadsheet and sorted according to the severity of each leak. The city uses this information to prioritize the dispatching of leak repair crews to sites.
City crews then use correlators to locate the source of a leak or break to within an approximate three-foot radius. Before repairing a leak site, the repair crew confirms the results of the correlation by using a ground microphone. Using a correlator and ground microphone enables the crew to only excavate a small area, providing for minimal disruption of traffic, the use of fewer resources, and a quicker repair of the leak.
Since Kingsport installed the new leak detection system, more than 116 distribution line leaks and breaks have been found, leading to repairs that now prevent the loss of nearly 1,200 gallons of treated water per minute. The system has been online and operational for nearly 26 months, resulting in annual water, energy and chemical savings that are making a positive impact on the city’s budget.
