Developing a Cip Using a Deterioration Modeling and Field Sampling Approach

Chartered by the State of Connecticut in 1929, the Metropolitan District Commission (District) provides water and sewer service to 12 communities, and more than 400,000 people in the Hartford, Connecticut area. Its water distribution system includes three water treatment plants, 1,600 miles of water mains, and 17 water pump stations.This project entailed the development of a 45-year capital improvement plan for the District's water distribution system assets. Project goals were to:Create a process for prioritizing and allocating funds for water infrastructure needs;Employ a computer model to simulate water main deteriorations and its impact on CIP expenditures;Establish a defensible, repeatable CIP process.Malcolm Pirnie compiled an asset inventory to ensure the District had a complete listing of all its assets. Then, the Integrated Decision Support System (IDSS) model was used to simulate asset deterioration and calculate anticipated CIP needs. Using historical data on water main breaks, a statistical evaluation was performed to develop pipe classes and deterioration curves for use in the computer model. To confirm and refine the data, Malcolm Pirnie performed field testing to ascertain in-situ pipe condition, and refined the pipe deterioration curves to improve model accuracy. Armed with the best data possible, Malcolm Pirnie configured the asset model, performed various model scenarios, and worked with the District to develop a 45-year CIP for water mains, valves, pump stations, and storage tanks.