The Glens Falls water supply system was developed in the 1870's, and continues to provide a plentiful supply of high quality water to residents and industry to this day, over 140 years later.

Early construction included water distribution piping and small intake dams on West Mountain that collected water from the Clendon Brook and the Halfway Brook. As the City grew, the upland reservoirs; Keenan Reservoir, Wilkie Reservoir, Butler Storage Reservoir and Butler Pond were constructed between 1878 and 1923. Raw water, originating from these reservoirs, flows by gravity to the Water Filtration Plant.

The Halfway Brook source, near the intersection of Dixon Road and Old Forge Road was initially an emergency water source, used during droughts in 1890 and 1922. A reservoir was created on this site in 1936 with Federal Public Works Administration aid. This reservoir includes a raw water pumping station that pumps up to 4 million gallons per day to the Water Filtration Plant.

The only treatment required for many years was disinfection, using chlorine. After the Safe Drinking Water Act was enacted, which required additional treatment for surface water supplies to better protect the public health, a Water Filtration Plant was constructed in 2003 in Coles Woods near Aviation Mall. This treatment plant uses a dual sand continuous filtration process with chlorine disinfection to protect the public water supply.

The City's water supply comes from five surface water reservoirs. Four are remote upland reservoirs on West Mountain: Wilkie Reservoir (80 Million Gallon Storage Capacity), Keenan Reservoir (322 Million Gallon Storage Capacity), Butler Storage Reservoir (57 Million Gallon Storage Capacity), and Butler Pond (270 Million Gallon Storage Capacity). These reservoirs are supplemented by Halfway Brook Reservoir (70 Million Gallon Storage Capacity), which is considered an auxiliary source since the water must be pumped to the filtration plant and has greater potential for contamination from the surrounding development. The creation of these surface water reservoirs and the associated embankment dams date back to the 1870s. The water from each of the four upland supplies is piped by gravity to a common point called Upper Junction, located on Aviation Road west of the City. Once combined at the Upper Junction, water proceeds via a 20-inch transmission main to the City's water treatment facility, located near Coles Woods.

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The Halfway Brook Reservoir water is pumped directly to the Filtration Plant via a 24-inch transmission main. The transmission mains from both the Upper Junction and the Halfway Brook Pump Station are discharged into a raw water intake channel at the water treatment facility.

The City's water treatment facility was constructed in 2003 and utilizes a two-stage upflow sand filtration system. The treatment facility has a maximum operating capacity of 8.9 million gallons per day (mgd) through the use of five filter units. Water entering the treatment facility undergoes both pre and post-chlorination, as well as sequestering for corrosion control. A coagulant is also added to the raw water for the filtration process. Finished water from the treatment facility is pumped to the City's two 2.3-million gallon (mg) water storage tanks located adjacent the treatment facility, prior to entering the distribution system.

The City has two existing interconnections with the Town of Queensbury water system: one interconnection is at the water treatment facility, and the other interconnection is located at Main Street and Western Avenue. These interconnections are available for emergency use only.

In 2008, a Water Supply Evaluation was completed by CHA (Albany, NY) to investigate the water supply alternatives for the Water and Sewer Board Commission, and City Council members. The evaluation compared several alternatives including rehabilitation of the five dams, decommissioning some of the reservoirs, using the Hudson River, well sources or the Town of Queensbury as a water supply and combinations of these options. The recommended alternative was to rehabilitate the existing reservoir infrastructure, which was ultimately chosen by the City based on reliability, constructability, water supply concerns, cost effectiveness and existing City agreements. This project has allowed the City of Glens Falls to maintain the water system that has provided the residents with reliable, high quality, potable water for over 100 years.

The five dams that impound each of the City's surface water supplies are currently on schedule for rehabilitation to be in compliance with the New York State Department of Environmental Conservation (NYSDEC) Dam Safety Guidelines. The City entered into a Consent Order Agreement (COA) with the NYSDEC on March 30, 2007 and amended August 7, 2008 to accomplish several tasks leading to rehabilitation of all five dams by June 2011. Each dam had several deficiencies which posed dam safety and operational concerns, including large tree growth on the slopes, inoperable low level outlet valves, insufficient spillway capacity for the design storm events, seepage and stability concerns. The City contracted with CHA to perform engineering services, including subsurface investigations, stability analysis, hydrologic and hydraulic analysis, dam inspections, dam modification design, permitting and construction observations. The City and CHA worked closely with the NYSDEC Dam Safety Section to develop cost effective designs to upgrade the dams and bring them into compliance with current regulations. In addition, Emergency Action Plans (EAP) were developed for each dam, which provides the City and first-responders with an understanding of the communication network and individual responsibilities in the unlikely event of a dam failure and uncontrolled release of water from a reservoir.

The COA included a schedule for the completion of certain phases or milestones. The City has completed the work on the Butler Pond, Butler Storage and Halfway Brook Reservoirs, and the remaining milestones are schedule to be completed well in advance of the assigned deadlines. The Keenan and Wilkie Reservoir Dams are currently under construction with a scheduled completion in late fall 2010. A summary of the COA schedule is provided in the table below:

The project had three general milestones for each dam as outlined by the COA. A breakdown of the tasks included in each milestone is provided below:

Milestone 1 Tasks:

• Dam Inspection and Repair Recommendations
• Hazard Assessment
• Site Topographic Survey and Mapping
• Subsurface Investigation and Embankment Stability Analysis
• Hydrologic and Hydraulic Analysis
• Emergency Action Plan Development
• Recommendations for Dam Modifications

Milestone 2 Tasks:

• Design New Spillways and Outlet Systems
• Improve Access Roads
• Design Seepage Controls and Embankment Stabilization
• Develop Construction Plans and Specifications
• Submit Permit Application

Milestone 3 Tasks:

• Project Advertisement and Awarding of the Contract
• Construction, and Construction Engineering Oversight & Quality Assurance
• Dam Rehabilitation Certification
• Inspection and Maintenance Plan Development and Implementation

The original project budget estimated the engineering inspection, evaluation and design, and construction for rehabilitation of all five dams at $13.6 million dollars. The 2010 updated project budget is at approximately $13 million dollars. This updated project budget includes the final engineering and construction costs of Butler Storage Reservoir Dam, Butler Pond Dam, and Halfway Brook Reservoir Dam, and the awarded contract amounts for the construction at Wilkie and Keenan Reservoir Dams. A summary of the costs per dam, as well as other project costs (legal fees, bond council, and alternative evaluation report) is provided in the table below: