HomeMy WebLinkAboutStaff Report Item 30 04/04/1988APR 4 1988 so `
AGENDA ITEM #
KEY WORD: Future Water
Requirements
DATE: 4/4/88
DEPARTMENT:
Thomas S. Hargis
Director of Public Works/City Engineer
REQUESTED COUNCIL ACTION:
Discuss future water needs of City to accommodate General
Plan growth and inform Sonoma County Water Agency (SCWA) of
projected needs.
RECOMMENDATION:
Discuss and request future expansion of 4.7 million gallons
per day (mgd) from Sonoma County Water Agency Aqueduct:,
BACKGROUND:
The EC14A is evaluating the future needs through 2010 of all
contracting agencies in consideration of expanding the
delivery capability of the water aqueduct system. Each
local agency has been requested to evaluate their future
needs and report same to SCWA. The Brown and Caldwell
Master Plan was based upon the previous General Plan. The
newly adopted General Plan and utility service boundaries
coincide very closely. The Master Plan found that, at a
buildout population of 68,400 in the year 2010, the City
would be short 0.4 mad if no changes occurred in local
supply. The new General Plan projects a buildout population
of 67,644 at 100% infill in 2005 or 60,386 at 75% in 2005.
The Water Master Plan assumes 74.5%, residential consumption
at a 145 gallons per capita per day (gpcd) rate. This is
based upon water conservation programs continuing to keep
consumption levels at a low rate. (Petaluma has been as
high as 158 gpcd in 1481.)
The Master Plan assumes in the year 2010, a demand for 21.7
million gallons per day. The existing commitment from the
SCWA Aqueduct is 17 million gallons per day. The existing
local supply of wells and the Lawler Reservoir System is
capable of providing 4.3 million gallons per day. This
leaves a 0.4 mgd shortfall. This also assumes a $636,000.00
Lawler system improvement (not including any right of way
acquisition costs). It also assumes the existing well
system can continue to be pumped at rates that currently
supply 183 of local demand. (The Local aquifer does have
limitations and is not a good recharge area.)
The staff recommends that the difference between the 2010
demand and the existing SCWA commitment be requested as
future needs, i.e., 21.7 — 17 = 4.7 million gallons per day.
This would provide that, if Lawler is not continued or if
wells cannot continue to produce at existing pumping rates
or water quality restrictions reduce the safe yield,
Petaluma could continue to meet the citizens' demands.
The Brown and Caldwell Master Plan recommends the City
continue to add wells to the local system in order to meet
our needs on a minimum day if water supply is interrupted
from the aqueduct. This would entail adding 8 wells of 0.29
million gallons per day or 2.3 million gallons per day total
by 2010. This provides an alternative to requesting
additional water from the SCWA. Two wells would make up for
the shortfall in 2010 of 0.4 million gallons per day.
The above discussion does not account for any projected
growth beyond 2010 in Petaluma's population. If Petaluma
continues to grow, either local supply must be increased or
the SCWA Aqueduct System expanded at that time.
ALTERNATIVES:
Request 0.4 mgd as a minimal amount. No request.
CONSEQUENCES OF NOT ACTING:
Delay input to SCWA for long range planning.
ACTION FOLLOWING AUTHORIZATION:
Transmit to SCWA.
Water