Weston Reservoir
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| Weston 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 | 60 acres |
| Max-length | ≈2.2 mi |
| Max-width | ≈1.6 mi |
| Surface area | ≈3.5 mi² |
| Average depth | 58 ft |
| Max-depth | 110 ft |
| Water volume | ≈200 million US gal |
| Shore length1 | ≈4 mi |
| Surface elevation | 200 ft MSL |
| Settlements | Weston |
| 1 Shore length is an imprecise measure which may not be standardized for this article. | |
The Weston Reservoir is part of the greater Boston’s water supply maintained by the Massachusetts Water Resource Authority (MWRA). Used only as a backup source, it is fed by the Wachusett Aqueduct and intermittently by the Sudbury Aqueduct.
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[edit] Description
Until the 1960s, the Weston Reservoir was the main receptacle, receiving water from the Wachusett Reservoir via the Wachusett Aqueduct, the main conduit used to deliver water to the greater Boston’s water system. At that time, it carried 300 million gallons of water each day. The Cosgrove Tunnel replaced it in 1965 at the primary water transmission aqueduct. Because of the construction of the water treatment facility at Walnut Hill, the Cosgrove Tunnel was shut down in 2003 in order to make the large piping connection between the new treatment plant and MWRA’s new MetroWest Water Supply Tunnel. The MetroWest Tunnel extends east 18.6 miles from Walnut Hill to Weston. During that shutdown, the Wachusett Aqueduct was the primary method of transmission of about 240 million gallons of water per day. It remains a backup connection to underground storage near the Massachusetts Turnpike in Weston as well as the Weston Reservoir.
Walkers extensively use the area around the Weston Reservoir. This reservoir is maintained along with other open distribution reservoirs (Sudbury, Foss, Brackett, Stearns, Norumbega, Waban, Spot Pond, Chestnut Hill and Middlesex Fells) as an emergency backup only. The MWRA's main distribution reservoirs are now covered storage facilities. The open reservoirs are maintained only as emergency backup supplies.
[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].
MWRA power generation
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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
- Storage specifications
- History and geography of facility
- Geographical coordinates
- Federal court order requiring water system changes
- EPA reports including Weston Reservoir
- Court order and statement of facts about MWRA facilities
