Water Supply and Demand
Massachusetts Water Resources Authority
| WATER SUPPLY STATISTICS |

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MONTHLY WATER SUPPLY
STATUS REPORT
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IN MAY 2008
overall demand on the MWRA system was
204.29 million gallons
per day, average
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QUABBIN RESERVOIR LEVELS |
AS OF JUNE 1, 2008
Elevation: 529.57 feet
Volume: 408.869 million gallons
Capacity: 99.2%
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WACHUSETT RESERVOIR LEVELS |
AS OF JUNE 1, 2008
Elevation: 389.38 feet
Volume: 57,567 million gallons
Capacity: 88.6%
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PRECIPITATION |
MAY, 2008
(monthly average)
Quabbin watershed: 1.23 in.
Wachusett watershed: 1.75 in.
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COMMUNITY WATER USE |
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MWRA WATER DEMAND vs. SAFE YIELD 1986-2006 |

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MWRA and the Division of Conservation and Recreation keep a daily watch on reservoir levels at Quabbin (412 billion gallon capacity) and Wachusett (65 billion).
While Wachusett levels are kept relatively fixed, Quabbin levels fluctuate with precipitation and watershed runoff.
Ware River stream flows are also watched daily to determine if seasonal
transfers to Quabbin during high-flow periods are possible. To gauge current
system status, water supply planners have identified six reservoir status
conditions that allow for normal monthly fluctuation.
The Quabbin/Wachusett system is so large that it can withstand short- and medium-length droughts and dry periods without a significant impact on its operating levels.
MANAGING DEMAND
Demand on the MWRA Waterworks system was 214.21 million gallons per day (average) in 2007. Information
on water use, system yield, watershed precipitation and levels of the
Quabbin Reservoir are tracked on a daily and monthly basis. Based on a
detailed analysis of major factors affecting water demand, MWRA projects
that system demand will remain well below 300 million gallons per day.
> Archive of water system demand
Safe Yield
MWRA's
source reservoirs, the Quabbin and Wachusett, can be counted on to safely
provide about 300 million gallons per day (mgd) of water. This is called
the "safe yield." For a 20-year period from 1969 to 1988, the customers
of MWRA (and its predecessor MDC) routinely drew more than the safe yield.
The chart above ("Historical Withdrawals") demonstrates this
historical trend. Fortunately, precipitation was great enough throughout
these years to avoid a major water supply crisis. To address this problem,
MWRA launched an aggressive water conservation program in 1986. By 1989,
withdrawals had been brought below the safe yield, where they have remained
ever since. This reduction in average water use was achieved through:
- Vigorous leak detection and repair efforts on MWRA and community pipes
- Retrofitting 370,000 homes with low-flow plumbing devices
- A Water Management Program for area businesses, municipal buildings and nonprofit organizations
- Extensive public information and school education programs
- A change in the state plumbing code requiring new toilets to be 1.6 gallon per flush
- Meter improvements that helped track and analyze community water use
- New water-efficient technology that has created reductions in residential use
- Water pipeline replacement and rehabilitation projects throughout the MWRA and community systems.
WATER SYSTEM STORAGE
Active Source Reservoirs
MWRA's two source reservoirs can the store 477 billion gallons of water for everyday use. Actual levels fluxuate.
| Source Reservoirs: 477 billion gallons |
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Quabbin Reservoir: 412 billion gallons
Wachusett Reservoir: 65 billion gallons |
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Archive of Quabbin Reservoir Levels | Archive of Wachusett Reservoir Levels
Active Supplemental Supply: 180+ Million Gallons
MWRA stores treated water in covered tanks across its service area. Water can also be drawn from the Ware River if needed.
| Covered Storage Facilities - 180 million gallons |
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Nash Hill: 25 million gallons
Fells: 20 million gallons
Loring Road: 20 million gallons
Norumbega: 115 million gallons |
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Ware River Withdrawals - amount varies
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Water can be drawn from the Ware River if needed. When the Ware River flow is above 85 mgd during the period from October 15 to June 15, withdrawals are sent to the Quabbin Reservoir. |
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Emergency Back-up Reservoirs
MWRA maintains a system of back-up reservoirs at points throughout its system for emergency use.
Emergency Back-up Storage: 11.2 Billion Gallons
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| Emergency Source Reservoirs |
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Framingham Reservoir #3 - 1.2 billion gallons
Sudbury Reservoir: 7.2 billion gallons |
| Emergency Distribution Reservoirs |
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Nash Hill: 25 million gallons
Fells: 20 million gallons
Loring Road: 20 million gallons
Norumbega: 115 million gallons |
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Rev.
June 26, 2008 3:21 PM
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