History of Whitehall Reservoir
Whitehall Reservoir was created to supply Boston with fresh water. While it is no longer used for that purpose, it is still connected to the “the only reserve drinking water supply  source for over two million residents of Eastern Massachusetts” via Whitehall Brook.Whitehall Reservoir’s role in what has since become known as the MDC is described in the following excerpt from “Sudbury Reservoir Watershed System, Public Access Plan Update 2002”from the Metropolitan District Commission  Division of Watershed Management   

During the nineteenth century, the Boston area had obtained water
mostly from Lake  Cochituate in Natick, a reservoir completed in
1848 under the auspices of the Boston Water  Board.  Some
communities were also served by the Mystic Lakes. By 1878, public
health  officials determined that these sources of supply would
prove inadequate, so a system of  seven reservoirs to supplement
the Cochituate system was constructed by the Boston Water  Board.
 These new reservoirs, created by holding back portions of the
Sudbury River, were: Sudbury, Whitehall, Hopkinton, Ashland,
Stearns, Brackett, and Foss (the last three referred to
respectively as Framingham Reservoirs Nos. 1, 2 and 3).

Limited yield, urbanization of the watersheds, and unsatisfactory
water quality led to an  investigation for additional water
supply of satisfactory quantity and quality.  A study  completed
by the state health board in 1895 recommended the development of
a reservoir  along the South Branch of the Nashua River.  The
predecessor to the MDC, the  Metropolitan Water Board, was
created in 1895 with the planning and development of the
Wachusett Reservoir.  The Wachusett Dam and Reservoir were
completed in 1908,  harnessing the Nashua River in central
Massachusetts as the new source of drinking water  for
metropolitan Boston.

The Metropolitan Water Board, Sewer Board, and Parks Commission
were combined by the Commonwealth as the Metropolitan District
Commission in 1919. State officials  realized during the 1920s
that, once again, additional sources of water were needed to
serve  the growing needs of Eastern Massachusetts.  The Quabbin
Reservoir was created in the  1930s, using the Windsor Dam to
impound the Swift River and flood an area formerly  occupied by
the four Western Massachusetts towns of Dana, Enfield, Greenwich,
and  Prescott.  The Ware River was also identified as a source of
water, which could be used  from October through June when flows
in the river are sufficient for diversion and there is
demonstrated need.  Diversions of water from the Ware River are
conveyed into the  Quabbin Reservoir at Shaft 11A through the
Quabbin tunnel aqueduct.

Since water started flowing from Quabbin Reservoir in 1948, no
new sources of drinking  water have been required to meet the
water supply needs of metropolitan Boston.  Through  ongoing
improvements of the distribution system by the MWRA and watershed
 management by the MDC, the current prognosis is that the
MDC/MWRA watershed  system will provide adequate supply and
delivery to the MWRA member communities well  into the 21 st

The creation of the Wachusett and Quabbin Reservoirs meant that
increasingly substandard  source waters from many of the
reservoirs in the Sudbury System could be discontinued.

The Whitehall, Hopkinton, Ashland and Cochituate Reservoirs were
transferred in 1947 to   the predecessor agency of the Department
of Environmental Management (DEM) for use  as State Parks.

Evidence of serious toxic pollution to the Sudbury River surfaced
in the late 1960s.  In  1970, the Nyanza textile plant was cited
as a source of mercury contamination and the site  was designated
as an EPA Superfund site in 1982. Wastes had contaminated the
sediments  in Reservoirs Nos. 1 and 2.  Significant progress has
been made on this clean-up, which is  being administered by the
US Environmental Protection Agency and the Massachusetts
Department of Environmental Protection.  A risk assessment is
currently underway on  segments of the Sudbury River.

The entire Sudbury System was officially removed from active use
and classified as an  emergency water supply in 1976.  Today only
the northern reservoirs (Sudbury and  Reservoir No. 3) are
classified as a reserve drinking water supply.  Reservoirs Nos. 1
and 2  are unlikely to be used as water supply in the foreseeable
future.  Some discussions have  occurred regarding disposition of
these two reservoirs and MDC lands surrounding them  for
recreational use.  No decisions, however, have been reached on
this issue.

The Sudbury Reservoir and Reservoir No. 3 remain the only reserve
drinking water supply  source for over two million residents of
Eastern Massachusetts. Although not currently in  use, the
reservoirs are on emergency standby to provide drinking water.

There are three emergency conditions that would require the use
of the Sudbury System:

-  Wachusett Reservoir is declared non-potable; -  there is an
inability to convey water from the Wachusett Reservoir to the
MWRA system (e.g., failure of the Hultman Aqueduct, Southborough
Tunnel, or the City  Tunnel); or -  a serious drought occurs.

Depending on the situation, the Sudbury Reservoir would be used
either as a primary  source of water supply, as a pass through of
Wachusett Reservoir water, or as a  supplemental source to the
Quabbin and Wachusett Reservoirs.