Quinapoxet River
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| Quinapoxet River | |
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| Origin | Princeton, Massachusetts |
| Mouth | Wachusett Reservoir |
| Length | 10.6 miles (17 km) |
| Source elevation | 802 ft (244.4 m) |
| Mouth elevation | 384 ft (117 m) |
| Avg. discharge | 88 ft³/sec (2.49 m³/sec) |
| Basin area | 57 mi² (147.6 km²) |
The Quinapoxet River is part of the Nashua River watershed. Its length is about 10.6 miles (17 km). It is part of the Massachusetts Water Resources Administration MWRA water system supplying drinking water to the greater Boston area.
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[edit] Description
The Quinapoxet River heads in Princeton, Massachusetts, the watershed generally known as the Upper Worcester Plateau, or the Monadnock Upland. This watershed tops at Wachusett Mountain, the highest feature in the area. Water flows east of this area feed the Nashua River Watershed and water flows west of this area feed the Ware River Watershed or the Millers River. This river flows through portions of Rutland and Holden before entering the confluence of the Stillwater and Nashua Rivers at the Wachusett Reservoir.
The Quinapoxet Dam in Holden impounds 1,100.0 million gallons in the Quinapoxet Reservoir, a Worcester, Massachusetts drinking water supply, before being released to flow towards the Wachusett Reservoir, joining the Stillwater River (to become the south branch of the Nashua River) at the Oakdale section of West Boylston. The city of Worcester can divert up to 36% of the Quinapoxet River water. The Quinapoxet Dam is an earthen dam with a concrete spillway. The outflow is not adjustable so the reservoir only supplies excess water to the Quinapoxet River.
| Quinapoxet Dam at Holden | Quinapoxet Dam Spillway |
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[edit] Information
The Quinapoxet and Stillwater Rivers are the two major tributaries to the Wachusett Reservoir. The Wachusett Reservoir serves as the primary source of water for 2.5 million consumers in 43 communities of central and eastern Massachusetts. The U.S. Geological Survey (USGS), in cooperation with the DCR Department of Conservation and Recreation, operates stream-flow monitoring gages near the mouths of both rivers. This and other continuous monitoring serves to maintain the overall quality of water within the reservoir. The water of these tributaries to the Wachusett Reservoir has been of high quality for decades.
| Quinapoxet headwaters at Princeton |
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About 35% of the Quinapoxet sub-basin is protected open space (Worcester reservoirs' surface water included). The City of Worcester owns the land that immediately surrounds each of its reservoirs and approximately 25% of its entire water supply watershed. It is a highly protected forest with no public access. Furthermore, the Massachusetts Water Resource Authority (MWRA) owns much of the land. The Town of Holden owns over 600 acres as the Trout Brook Conservation Area, and Massachusetts Audubon Society owns several hundred acres in the Wachusett Meadow Wildlife Sanctuary in addition to other properties within this sub-basin.
The lower Quinapoxet rates on alert for biology, chemistry and hydrology. Chaffin's Brook is considered a "moderately septic polluted stream" and its lower reach has noxious aquatic plants in an impoundment. Trout Brook in Holden is considered to be high quality habitat and have limited disturbance. There are a number of medium yield aquifers surrounding Holden center and to protect this resource the town has passed an aquifer protection bylaw.
[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
- Stillwater River monitoring at Wachusett Reservoir
- Quinapoxet River information
- Quinapoxet River monitoring at Canada Mills
- Court order and statement of facts about MWRA facilities
