Wachusett Reservoir
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| Wachusett Reservoir | |
|---|---|
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| Coordinates | |
| Lake type | Reservoir |
| Primary sources | 240 million US gal / day |
| Primary outflows | 240 million US gal / day |
| Catchment area | 108 mi² |
| Basin countries | USA |
| Max-length | ≈7 mi |
| Max-width | ≈1.1 mi |
| Surface area | ≈7 mi² |
| Average depth | 48 ft |
| Max-depth | 120 ft |
| Water volume | ≈65 billion US gal. |
| Shore length1 | ≈37 mi |
| Surface elevation | 384 ft MSL |
| Settlements | Clinton, Lancaster, West Boylston, Boylston, and Sterling, Massachusetts |
| 1 Shore length is an imprecise measure which may not be standardized for this article. | |
The Wachusett Reservoir is the second largest body of water in the state of Massachusetts. It is located in central Massachusetts, northeast of Worcester. It is part of the water supply system for metropolitan Boston maintained by the Massachusetts Water Resource Authority (MWRA). It has an aggregate capacity of 65 billion U.S. gallons (240 million m³) and an area of almost 7 square miles (18.2 km²). Water from the Wachusett flows to the Weston Reservoir by way of the Wachusett Aqueduct. It has a maximum depth of 120 feet (36.5 m) and a mean depth of 48 feet (14.6 m).
The reservoir is fed by the Nashua, Quinapoxet, and Stillwater rivers, along with the Quabbin Aqueduct, which carries water from the Quabbin Reservoir.
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[edit] History
In 1897, the Nashua River above the town of Clinton was impounded by the Wachusett Dam. 4,380 acres (17.5 km²) were flooded in the towns of Boylston, West Boylston, Clinton and Sterling. Work was completed in 1905 and the reservoir first filled in May 1908.
West Boylston’s prominent land mark – The Old Stone Church - was left remaining as a reminder of those that lost their homes and jobs to the building of the reservoir. It is one of the most photographed sites in the area.
When it was built, the Wachusett Reservoir was the largest public water supply reservoir in the world and the largest body of water in Massachusetts.
[edit] Recreation and Fishing
Because the reservoir is the water supply for Boston, not all areas around it are open to the public. To assure pure water, there are a number of regulations prohibiting boats, ice fishing, wading, swimming, overnight camping, alcoholic beverages, littering, animals, bikes and motor vehicles from the reservoir and abutting property. A network of fire roads provides easy access for hikers and cross-country skiers.
As of 1999, the reservoir contained 12 native and 12 introduced species of fish. The limited access, combined with abundant, high quality habitat, produced state records for brown trout, land-locked salmon, smallmouth bass and white perch. Approximately 80% of the 37 mile (59.5 km) shoreline is usually open to angling from April 1 through November 30, depending on ice conditions. These regulations are controversial as their is little evidence recreational activity through fishing and non motorized or electric powered boating can actually cause contamination to untreated, raw water.
[edit] MWRA water system overview
The MWRA and the Massachusetts Department of Conservation and Recreation (MDCR) own and operate the collection, treatment, distribution, and storage facilities that supply drinking water to some forty municipalities in the metropolitan Boston area. This water system design was based upon the purchase and subsequent protection of an entire watershed. This design assures that the water remains as pristine as possible. However, modern regulations require that all supplies of drinking water be chemically treated regardless of the source[1]. Additions to the MWRA water system throughout its history have resulted in redundancies that allow major sections of the water system to be shut down for repair or maintenance.
[edit] Water flow
Water flows from the MWRA's main storage facility, the Quabbin Reservoir in central Massachusetts, through the Quabbin Aqueduct to the Wachusett Reservoir in and around Boylston and Clinton [2]. Tributary rivers and streams comprising the Wachusett watershed, a 108 square mile (280 square kilometer) drainage basin, also feed the Wachusett Reservoir. At the eastern end of the Wachusett Reservoir, water enters the Cosgrove Tunnel at the Cosgrove Intake. The Cosgrove Tunnel feeds both the MetroWest Water Supply Tunnel (MWWST) and the Hultman Aqueduct. The MWWST starts from the Carroll Water Treatment Plant in Marlborough. The Hultman branches off at Framingham in two directions. The smaller branch, the Weston Aqueduct, empties into the Weston Reservoir in Weston. The main branch continues to the Norumbega Reservoir, also located in Weston[2].
[edit] Redundancy
Water can be treated with chlorine as it leaves the Wachusett Reservoir in an emergency, and again as it leaves the Norumbega Reservoir. This is to provide for a backup to the new water treatment facility, the John J. Carroll Water Treatment Plant, which started operation on July 27, 2005[3]. This plant is of modular design and provides ozonation for primary disinfection, chloramination for residual disinfection, fluoridation, and pH control.
[edit] John J. Carroll water treatment plant
Located at the town lines of Marlborough, Northborough, and Southborough, Massachusetts, this facility replaces the one used previously only for pH control[4]. It comprises four ozone generators with diffusers and five concrete contact chambers with a volume of 11.3 million gallons (42.7 million liters). The plant has a capacity of 275 million gallons (1.04 billion liters) per day, on an average day or 405 million gallons (1.53 billion liters) per day, at peak level. It cost US$340 million[3].
[edit] Electrical generation
The system includes three hydropower stations, with a total capacity of 8 MW[5]. Water released to the Swift River flows through the turbines at Winsor Station below the Winsor Dam. Water transferred from Quabbin to Wachusett can pass either through the turbines at Oakdale or through bypass pipes when flow requirements exceed turbine ratings. Water released from Wachusett into the Cosgrove Tunnel passes through the Cosgrove turbines[2][3].
The Quabbin Aqueduct connects the two reservoirs, and relies upon gravity to accommodate the three separate operational needs. First, diversion of water from the Ware River into the Quabbin Reservoir uses this aqueduct. Second, water transfer from the Quabbin Reservoir to the Wachusett Reservoir, through a hydropower station or a bypass pipe, uses it as well. The bypass valves are non-regulating valves, and when opened, only the head in the Quabbin Reservoir and the physical characteristics of the aqueduct govern the flow. Because the turbines are flow limited, the bypass mechanism permits transfer rates nearly twice as high as are possible through the turbines. Operationally, the single aqueduct fulfills three purposes, but only one operational mode is possible at a given time [6].
[edit] MWRA references
- ^ Safe Drinking Water Act. Retrieved on 2006-12-01.
- ^ a b c MWRA water system. Retrieved on 2006-12-01.
- ^ a b c Water system history. Retrieved on 2006-12-01.
- ^ John J. Carroll water treatment plant. Retrieved on 2006-12-01.
- ^ Electrical power generating plants. Retrieved on 2006-12-07.
- ^ Water system configuration. Retrieved on 2006-12-01.
[edit] References
- Massachusetts Dept. of Conservation and Recreation Wachusett Reservoir page
- MWRA Wachusett Reservoir History
- MassWildlife Wachusett Reservoir Fishery page
- Historic Photos from the MIT archives
- Mass Central Rail Trail Rails To Trails conversion on the Central Mass line, which was rerouted during dam construction.
- Court order and statement of facts about MWRA facilities
