Rocky Flats Plant, Water Treatment Plant
HAER No. CO-83-AC
(Rocky Flats Plant, Building 124)
Rocky Flats Environmental Technology Site, Highway 93, Golden, Jefferson
County, Colorado. Building 124 is located in the northwest quadrant of the Rocky Flats
Plant, west of Third Street, north of Cedar Avenue.
This building is a secondary contributor to the Rocky Flats Plant historic
district, associated with the U.S. strategy of nuclear military
deterrence during the Cold War, a strategy considered of major importance in
preventing Soviet nuclear attack. Building 124 was built in 1952, and has
treated, stored, and distributed all plant water since 1953. The water system
was designed to meet all existing and future plant needs and will remain in
production until the plant is completely closed.
Building 124, the Water Treatment Plant, has a concrete foundation and
walls, and metal, shallow-pitched gable roofs. It encompasses approximately 4,250 square
feet in a roughly rectangular shape. The windows are industrial, multi-pane with metal
sash. The doors are metal.
Raw water is purchased from the City and County of Denver and is drawn from two
Denver-owned sources, Ralston Reservoir and the South Boulder Diversion Canal. Water from
these two sources is typically pumped to a raw water storage pond on the west side of the
plant before entering the water treatment system.
Building 124 has a nominal treatment capacity of 700 gallons per minute (gpm). It is
comprised of a flocculation tank, gravity-sand filters, chemical feeders, chlorination
equipment, distribution pumps, and facilities for recycling backwash water. Alum, lime,
and chlorine are added to the water as it flows into a coagulation and clarification
basin. After clarification, the water flows through rapid-sand filters and is chlorinated
prior to entering the finished water storage system. Blowdown water from the clarifier and
backwash water from the microstrainer and filters is processed through settling basins for
removal of solids. The clarified water from this operation is pumped back into the raw
water system while the solids are pumped to drying beds and then are taken to the
landfill. Treated water flows from Building 124 to a clear well. From there it is pumped
into a ground-level tank (Building 215B) and then either into an elevated tank (Building
215A) or the plant distribution mains, according to demand. Potable water is distributed
for domestic, process, and fire protection uses throughout the plant site.
Pumping capability for the treated water at Building 124 relies upon five electric
pumps. A 1,000-gpm pump moves treated water from the clear well to the ground-level tank,
which has a capacity of 500,000 gallons. One 700-gpm and two 500-gpm pumps deliver water
from the clear well or the ground-level tank to either the elevated tank or the plant
treated water distribution system. These three distribution pumps cycle automatically to
maintain a minimum of 220,000 gallons in the 300,000-gallon capacity, 155-foot-high
storage tank. Normally, only two of these three pumps are on line at one time. A fifth
pump can pump water from either the clear well or the ground-level tank to the
distribution system at 1,500 gpm in the case of fire or emergency. In case of a power
outage, there is a 225-kilowatt emergency generator to keep the pumps operational.
Filter backwash water from Building 124 is reprocessed in a facility that has two
60,000-gallon storage tanks, two drying beds, and several pumps. This facility permits
reuse of this highly turbid water, eliminating its discharge off site.
An alarm system, dedicated to the Water Treatment Plant, is maintained in Building 124.
Alarms sound when water levels in the tanks are too low or too high, when flow to the
distribution system is excessive, or when various operations in the backwash cycle
Near Building 124 there is a connection whereby, in an extreme emergency, the incoming
raw water main can be connected directly to the treated water distribution main, bypassing
all storage tanks and the treatment plant. To make this change, it is necessary to
manipulate valves and physically rebolt a flange.
Construction of Building 124 began in 1952. The complete plant water
supply, treatment, storage, and distribution system went into production in 1953 and has
operated uninterrupted since that time. Until the system was operational, water was
brought to the plant from Boulder in tank trucks. The water system was designed to meet
all existing and future plant needs and will remain in production until the plant goes out
United States Department of Energy. Site Safety Analysis Report,
Notebook 11-Security, by EG&G Rocky Flats, Inc.
Rocky Flats Repository. Golden,
United States Department of Energy. Final Cultural Resources Survey Report (1995), by Science Applications International Corporation. Rocky Flats Repository. Golden,
Web, David, employed at the plant since 1977 by the site contractor.
Personal communication, November 1997.
D. Jayne Aaron, Environmental Designer, engineering-environmental
Management, Inc. (e2M), 1997. Judith Berryman, Ph.D., Archaeologist, e2M,
Index to Photographs
Located west of Third Street and north of Cactus Avenue, Golden Vicinity, Jefferson County, Colorado.
Photograph CO-83-AC-1 was taken by Rockwell International on October 10, 1988.
CO-83-AC-1– View of Building 124, the Water Treatment Plant, looking northeast. The Rocky Flats Plant water supply, treatment, storage, and distribution system has operated continuously since 1953.