History of the Libby Water Distribution System
Libby’s water distribution system contains approximately 38 miles of distribution piping. The pipe sizes range between 2-inch and 10-inch, and generally consist of steel in the older areas of town and PVC in the newer areas. The distribution system was constructed beginning in 1911. Many of the mains have provided service well beyond their functional service life and are now beginning to fail.
Libby’s unaccounted for water loss is unusually high for a municipal water system. The average unaccounted water from 2006 to 2010 was approximately 28 million gallons per month (620 gallons per minute). This represents 74 percent of the total treated water entering the system.
Sources of water loss in the system include:
- Main and Service Leaks
- Unmetered Irrigation
- Broken Meters
- Inaccurate Meters
In an effort to reduce the amount of leakage in the system, the City of Libby commissioned a leak detection study in 2011. This report identified numerous leaks in the distribution system and estimated the volume of water lost through these leaks. The estimated volume of water loss due to leaks is approximately 14 million gallons per month (310 gallons per minute).
The entire water distribution system currently operates within a single pressure zone. As a result, the City cannot control the pressures in localized areas (i.e. they have to increase or decrease the pressure of the entire system). This results in low pressures in the south and west areas of the system, and the potential for excessive pressures in the north and east areas, closer to the Kootenai River. The proposed water system improvement project addresses the water losses and the pressure variations in the system.
Main Replacement and Pressure Reducing Stations Project – The City of Libby will replace approximately 1,600 feet of water mains that are contributing to the highest amount of water loss. The City will provide information regarding the location and extent of these projects as the final design progresses. The City of Libby will also install a series of pressure reducing valve stations (PRV stations) to increase low pressures and to moderate high pressures. The PRV stations project includes the installation of five new PRV stations and approximately 2,900 feet of new water main. These improvements are projected to eliminate approximately 8.6 million gallons of water lost to leaks each month. The total estimated project cost is $1,776,000. The estimated construction start date for this project is April 2013.
Water Meter Replacement Project – The City of Libby has implemented a meter installation and replacement program to account for water through non-registering meters and non-metered connections. This is an ongoing project that will continue beyond the current water system improvement projects.
The City of Libby has submitted a funding application to the United States Department of Agriculture – Rural Development. The City may be eligible for up to 45% grant funding for this project with the remaining 55% funding through a low interest loan. This funding is anticipated to be available in late 2012.
Project Area Map