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Water Supply and Demand
Massachusetts Water Resources Authority

WATER SUPPLY STATISTICS

quabbin reservoir photo

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MONTHLY WATER SUPPLY
STATUS REPORT

WATER SYSTEM DEMAND

IN MAY 2008
overall demand on the MWRA system was
204.29 million gallons
per day, average
(+ change)
Archive

QUABBIN RESERVOIR LEVELS

AS OF JUNE 1, 2008
Elevation: 529.57 feet
Volume: 408.869 million gallons
Capacity: 99.2%
(- change)
Archive

WACHUSETT RESERVOIR LEVELS

AS OF JUNE 1, 2008
Elevation: 389.38 feet
Volume: 57,567 million gallons
Capacity: 88.6%
(- change)

Archive

PRECIPITATION

MAY, 2008
(monthly average)

Quabbin watershed: 1.23 in.
Wachusett watershed: 1.75 in.

Archive

COMMUNITY WATER USE
Community Use Data

Monthly and year-to-date water use comparisons for MWRA communities

Current Report and Archive

MWRA WATER DEMAND vs. SAFE YIELD 1986-2006

MWRA WATER DEMAND vs. SAFE YIELD  1985-2004

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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
  Quabbin Reservoir: 412 billion gallons
Wachusett Reservoir: 65 billion gallons

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
  Nash Hill: 25 million gallons
Fells: 20 million gallons
Loring Road: 20 million gallons
Norumbega: 115 million gallons
Ware River Withdrawals - amount varies
  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.

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
Emergency Source Reservoirs
  Framingham Reservoir #3 - 1.2 billion gallons
Sudbury Reservoir: 7.2 billion gallons
Emergency Distribution Reservoirs
  Nash Hill: 25 million gallons
Fells: 20 million gallons
Loring Road: 20 million gallons
Norumbega: 115 million gallons

Rev. June 26, 2008 3:21 PM

Historic Withdrawls Reservoir Levels