Missouri River Treatment Plant - Executive Summary
Description of water system for Helena, Montana |
The City of Helena's Water Department (HWD) goal is to ensure customer
satisfaction by consistently delivering high quality water today and in the future.
The HWD serves more than 25 thousand customers with 9364 service taps including 155 fire
lines with an average of 5.2 million gallons of water per day on an annual basis. The total annual
gallonage from all sources for 1998 is 1.866BG* with a peak day of 12.2MG*. To supply this
amount of water, we operate two surface water treatment plants--the Missouri River Water
Treatment Plant (MRTP) located at 2560 Canyon Ferry Road, and the Tenmile Water Treatment
Plant west of Helena at 1115 Rimini Road. The Tenmile Water Plant is in operation year round
while the MRTP is used only during the summer months for peak demands. Additional water is
obtained from the Hale system which consists of the Oro Fino and Eureka well collectors. The
department's two treatment plants are maintained, evaluated
and upgraded to stay abreast of
advancements in technology, health science and governmental regulations.
The Helena water distribution system consists of five finished water storage reservoirs (Malben,
Winne, Hale and Upper Hale, Woolston) and pumping stations (Forrest Estates, Hale, Eureka,
Dahlhausen, Reeders Village) linked together with 185 miles of water transmission and
distribution pipelines. The Chessman (530MG) and Scott (195MG) reservoirs in the Tenmile
watershed also provide additional water for the Tenmile Water Plant during low flows. These
reservoirs are filled with spring run off water.
Carollo Engineers of Boise, Idaho completed a Water Master Plan Update for the City of Helena
in April 1997. The Public Works Department has copies of the Water Master Plan if customers
would like to review it. Phase one of this update determined that the existing Missouri River
Treatment Plant should be rehabilitated or replaced due to age of equipment, public health risks,
ational safety issues. Plant replacement or rehabilitation costs were significant. The least
costly scenario was to replace the capacity of the existing plant with high quality groundwater
supplies if available. Test drilling of these wells has started in 1998.
The Facility and Regulated Substances
This is a local government owned and operated facility for the production of potable water for the
City of Helena. The only reportable regulated substance for the RMP plan is chlorine. One to
two tons of chlorine are stored at this facility in ton cylinders. No more than two ton cylinders
are on line at a time. The online tanks are on isolated regulators that reduce the chlorine pressure
to a vacuum state. Chlorine feed equipment supplies a vacuum to the tanks allowing the release
of chlorine to the feeders. All feed lines supply chlorine below atmospheric pressure. Should a
leak develop the feeders would be unable to supply enough vacuum to continue the release of
chlorine and the f
eed would stop at the Chlorine Pressure Reducing Valve(CPRV) attached to the
tank. Each tank has its own CPRV. No flammable substances are stored in the chlorine room.
Two operators are required for changing chlorine tanks as part of our standard operating
procedures. Self Contained Breathing Apparatus(SCBA) are stored in an adjacent room on wall
mounted quick release brackets. An emergency repair kit is available. A chlorine detector is
installed in the room connected to an alarm panel and autodialer. If an alarm condition exists it
will call personnel till acknowledged. All alarms and autodialers are on uninterruptable power
The worst case scenario would be the total loss of one ton of chlorine through catastrophic valve
or tank failure. There are no mitigation controls. Response time could be so limited(less than an
hour)that under the right conditions total loss of one ton of chlorine is possible.
e or leak while tank is being changed. The least worst case scenario would by CPRV
failure, CPRV to tank connection, or tank valve leak. Operators would close the tank valve thus
shutting off the chlorine so repairs can be made.
Accidental Release Prevention
Operators are trained in the proper way to change tank CPRV's. Regular maintenance is kept on
the CPRV's, lines, and feeders. Cylinders with exceptionally difficult or tight valves are
returned. SCBA's are kept in a separate room. Operators are trained in proper leak detection and
correction needed. Two operators are required for tank changes or repairs. A third operator is
notified of any leaks and told to notify emergency responders if no communications for more
than 20 minutes.
Five Year Accident History
No accidents in the last five years.
Emergency Response Program
As written in the plant emergency response manual. This manual is stored on the office desk.
These manuals are stored in plain view by office door.
New improvements include a groundwater supply in combination with a new Missouri River
Treatment Plant. This includes a new clearwell, chlorine equipment, and high service pump
station. Storage includes a new east side reservoir. This new construction will begin in one to
two years from now depending on budget restraints and final approval from City and Community