NPU Capital Efficiency Plan™ including Water Infrastructure Asset Management

Norwich Public Utilities (NPU) Capital Efficiency Plan™ — Water Infrastructure Asset Management including System Hydraulic Evaluation and Critical Component Assessment

NorwichTata & Howard completed a comprehensive Capital Efficiency Plan™ for Norwich Public Utilities (NPU). The Capital Efficiency Plan™ followed our three circle approach including a system hydraulic evaluation, critical component assessment and asset management considerations. The NPU distribution system is comprised of approximately 180 miles of water mains of various material types with pipe ranging in diameter from 2 to 30 inches. During the course of the project, Tata & Howard worked closely with NPU staff and other City of Norwich Departments. Meetings and workshops were held with operations and engineering NPU departments as well as with the numerous fire departments that cover the greater Norwich area. The final report included a prioritized list of recommended water main rehabilitation and replacement projects and the associated estimated costs for those projects. In addition, water storage tank stagnation issues were identified. Since completion of the Capital Efficiency Plan™ NPU authorized Tata & Howard to complete a system gradient study that evaluated how to significantly improve water quality in the distribution system and adjust system pressures to reduce system leakage while maintaining an appropriate amount of system storage. NPU has further authorized Tata & Howard to conduct preliminary engineering analysis that will lead to the design and construction of new storage tanks, pump replacements, water mains, and energy saving alternatives.

Tata & Howard was retained by the NPU to evaluate the water age, water quality, and hydraulic gradient in the Taftville/Occum Service Area. The Taftville/Occum Service Area has high water age, due primarily to the large volume of the Occum Tank. In addition, high levels of total trihalomethanes (TTHM) are observed throughout the Taftville/Occum Service Area. To evaluate the Taftville/Occum Service Area, the entire NPU distribution system needed to be examined to determine the quality of the water as it enters the service area. The findings were based on an analysis of the field sampling results, the Simulated Distribution System and chlorine bottle decay tests performed in August and September 2012, and numerous scenarios examined using the WaterGEMS hydraulic model of the NPU distribution system.