HISTORY
The Vallejo Sanitation and Flood Control
District was created by a special act of the
California State Legislature in 1952. This
act was put forward by the City of Vallejo
and Solano County for a service area that
encompassed approximately 23 square miles,
most of it unincorporated county land. Our
current service area is approximately 26
square miles, 90% of it incorporated into
the
City of Vallejo.
WASTEWATER TREATMENT
Since its inception, the District has worked
to improve the quality of wastewater
discharges to the Carquinez and Mare Island
Straits. In 1952, untreated sewage and
stormwater flowed through a common piping
system and were discharged into the Mare
Island Strait at 14 different locations.
By 1959, the District's first wastewater
treatment plant was brought on line, greatly
reducing the amount of untreated sewage
discharged to the Mare Island Strait. Sewage
flows through pipes to our modern wastewater
treatment plant at 450 Ryder Street in
southwestern Vallejo. The plant has a dry
weather capacity of 15.5 million gallons per
day (mgd) and a wet weather capacity of 60
mgd. |
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WASTEWATER SYSTEM IMPROVEMENTS
Early 1970s
The original 1959 plant was designed to
treat sewage only to a primary level,
clarifying the wastewater by removal of
material by settlement and skimming. In
1972, new regulations from the U.S.
Environmental Protection Agency necessitated
the construction of a secondary treatment
plant. Secondary treatment removes the
biological elements remaining in wastewater
after primary treatment.
1977 - 1985
Vallejo's secondary facility was completed
in 1977. During initial efforts to bring the
new plant on-line, it became obvious that
the plant was not going to work properly.
The plant used an innovative
physical/chemical process, hailed at the
time by federal and state regulators as the
"process of the future." In 1981, this process was
declared a failure by the regulators who
once praised it.
In 1985, after considerable legal battling
and political effort, the federal and state
governments acknowledged their
responsibility to assist in correcting the
failed plant.
1988 - Present
A new secondary facility was
completed in 1988, which
included a trickling filter/solids
contact
biological treatment process,
a new operations building, and
additional chlorination and
de-chlorination disinfecting
facilities.
The new plant
uses the same process that
nature does to clean water in
streams and rivers. Once the
water is cleaned and returned to
the Bay, the dried biosolids
that are left are treated and
used as a soil amendment and
fertilizer at the District-owned
Tubbs Island farm in Sonoma
County. Secondary treatment
dramatically improves the plant's effluent
quality. To address long-term wastewater
treatment needs, the District developed a
20-year Master Plan for wastewater capital
facilities that included a program to
eliminate wet weather sewage overflows to
surface waters entering San Francisco Bay.
This effort involved the construction of new
wet weather treatment facilities at the
existing wastewater treatment plant as well
as improvements to the District's collection
system. The new plant facilities were
brought on line in 1991. These improvements
increased the plant's capacity from 30 mgd
to 60 mgd during wet weather flows. The
District also increased the size of several
pipes within the collection system between
1988 and 1995. In 1992, an
Inflow/Infiltration Control Program was
prepared. The District currently follows
this program as a means to reduce the
entrance of rainwater into the sanitary
sewer system.
SANITARY SEWER OVERFLOWS
Pipes that carry wastewater to the plant are
made out of various materials ranging from clay
and cement to materials made of paper and
tar called Orangeburg that were installed
during World War II. Over time, tree roots and
ground settling can cause the pipes to
develop small cracks that allow excess
rainwater and ground water to flow in.
Wastewater flows can increase from an average of 13
million gallons per day in dry weather to
60 million gallons per day during
heavy rains. The District is currently in
the process of implementing a $60 million
program to make the system repairs and
improvements necessary to eliminate
overflows.
STORM DRAIN SYSTEM
The District has also made improvements to
the storm drainage system. There are more
than 150 miles of pipes and channels, as
well as four pump stations that provide
drainage in the Vallejo area. The District
maintains these storm drains. Severe
flooding in the Vallejo area has been
reduced substantially. Major facilities
constructed include Lake Dalwigk and Austin
Creek in the 1950s, and facilities below
Lake Chabot Dam in the late 1980s and early
1990s. Engineers use a formula to measure
the intensity and quantity of rain that
falls during a storm. Each storm is given a
rating that is measured by "years." A
15-year storm means that the area is likely
to experience a storm of similar capacity
only once in 15 years. Likewise a 100-year
storm means that a similar storm would be
expected in the area only once in 100 years.
The District has a minimum capacity
requirement for new drainage systems. New
public systems must have a capacity to
convey the 15-year storm design. Since 1988,
if the area drained is one square mile or
larger, the required capacity is conveyance
for a 100-year storm. The District continues
to follow the Storm Drain Master Plan
prepared in 1987 and updated in 2003. |
