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October 11, 1990
THE HONORABLE CITY COUNCIL
Palo Alto, California
Hetch-Hetchv Water System shutdown
Kembers of the city council:
Report in erief:
The purpose of this staff report is to provide Council with
information on the shutdown of tba Hetch-Hetchy Sierra Reservoirs
and Delivery system during November 1990. The closing of these
reservoirs and delivery system is for tbe purpose of repair and
maintenance. This is an informational staff report and no
council action. is t: equ ired .
Background
As part: of a norma.l ~OlJt inc of the san Francisco Water Department
{SFWD). portions of the ... ·ater delivery system are shut down
periodically for repairs and maintenance. Usual.ly, these repairs
and shutooWl\s occur during the -months of January and February ..
the period of lowest water demand~ This bas been the case
several times in recent year6 to repair portions of the Hetch
Hetchy Syst:em~ DUring these sbutdowns, water del iveries <::ontinue
in a normal manner from the tour Bay-Area reservoirs of the SFWD
system; the Calaveras and San Antonio reservoirs near sunol in
the East Bay; and San Andreas at crystal Springs reservoirs in
San MateD county near 1280 and Higb~ay 92.
What is unique about the Hetch-Hetchy system shutdown this tima
is that it vi11 occur during November,. a time when 'Water ilemand
is somewhat elevated~
This shutdo',ro. needs to <>c::cur in NoveI!lber due to the location of
the area needing repair. The Hetch-Hetchy Mountain Tunnel lining
bas been deteriorating and leaking has oocurred~ This Mountain
Tunnel is a critical component of a complex system that
transports vater from the Sierras to the Bay Area~ ~~e location
of these leaks is in an isolated canyon area that requires dry
weather and clear roads to facilitate the repairs~ Therefore~
Sr~D must perform these repairs before the winter begins.
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Discussion
SFWD has been vorkinq with the suburban wholesale agencies to
prepare for this event~ SFWD has listed possible worst case
scenarios~ such as equipment failures l pressure fluctuations and
unseasonably warm weather (bigh water demands). The Operations
Division of the utilities Department has been briefed on these
conditions and is reedy to respond by operating standby wells if
necessary.
In anticipation of this l the Operations and Engineering Divisions
have installed special valves on each of the four emergency
backup municipal wells. This will minimize the ·shock-of water
entering the water distribution system and stirring up the
sediment in the pipe lines.
Probably the only noticeable effect for the customers of the
water utility will be a small change in the hardness of the
water. This means that a little more soap ~ill be needed for
daily tasks. There may be a minor change in the taste of this
~ater, but it will at all times exceed drinking ~ater standards
for potable ~ater.. This minor change in water quality is due to
'Water being supplied from local reservoirs and not the Hetcb
Hetcby Hountain System.
The Energy Services group of Resource Planning has personally
contacted larger customers who are water quality sensitive~ to
make them aware of this situation and allow them to take
appropriate measures to continue their processes during this
time. Also1 an informational mailing has been sent to all major
account customers. Near the tirue of the shutdown, residents ~ill
be alerted through a series of newspaper ads and press releases.
To notify smaller commercial customers~ an informational m~iling
will be sent.
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