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Representative Projects in the Last Five Years
LSCE has served as the District’s consultant on numerous
related projects concerning water supply development
and a large recycled water injection program in the
Amador Valley region east of the San Francisco Bay
Area. LSCE performed detailed basin analyses using
existing information supplemented by test hole exploration
drilling at 10 sites. Lithologic cross sections
were constructed to identify drilling targets and
define distinct hydrogeologic units. Activities
also included construction of several multiple completion
monitoring wells for ground-water sampling and water
level measurements. LSCE was sole-sourced as the
District’s design engineer for well planning and
design associated with a recycled water program consisting
of injection of up to 2.5 MGD of reverse-osmosis
treated waste water. Design considerations included
assessing long-term monitoring of injected recycled
water, Department of Health Services criteria for
travel time and offsets from domestic water supply
wells, water stabilization, impacts on surface mining
operations in the vicinity of the injection wells,
operating protocol, and others. LSCE also performed
design work on surface facilities, including injection
stations.
LSCE
conducted an investigation
of ground-water conditions along the Middle Reach of
the Russian River in Sonoma County during 1995 through
1998. A numerical ground-water flow model was developed
for the Valley to evaluate potential ground-water impacts
resulting from the planned expansion of wet-pit mining
along the River in accordance with the Sonoma County
Aggregate Resources Management (ARM) Plan. The scope
and extent of the impact evaluation include the entire
middle reach, and the model has been used to simulate
impacts of multiple phases of mining on both sides
of the River as well as the impacts of increased municipal
pumping by the Town of Windsor (from a multiple well
field immediately adjacent to the River) and increased
pumping from new Ranney collectors proposed by the
Sonoma County Water Agency (installed immediately adjacent
to the River), both of which are contiguous to mining
operations.
Managed the detection, verification and
corrective action programs at Sacramento County's largest
landfill. Work
at the landfill has included saturated and unsaturated
zone hydrogeologic and hydrochemical characterization,
soil gas investigation, a seismic reflection and
refraction program to identify offsite leachate migration,
and capture-zone analyses to recommend a ground-water
extraction and treatment program. Managed work related
to the design and implementation of full scale ground-water
extraction and treatment facility (1,300 gpm capacity). Other
work at the landfill has included NPDES permitting,
Army Corps of Engineers permit for streambed alteration,
master plan for water supply, modification and abandonment
of existing water supply well, and design and construction
of onsite water supply well. Work at the Sacramento
County's largest landfill as a subconsultant on a
project to identify source control methods or combinations
of source control methods for possible implementation
to prevent ground-water contamination. Field investigation
conducted to verify estimates developed of the contamination
in the unsaturated zone and to finalize the design
basis for a staged remediation. Provided hydrogeochemical
interpretation of the complex subsurface unsaturated
and saturated units to assist with the preliminary
design of effective contaminant control measures.
LSCE provided services
to the City of Rohnert Park to prepare the ground-water
portion of the Water Supply Assessment (WSA) needed
to satisfy the requirements of Senate Bill 610 (SB
610) and the City’s Water Policy Resolution. The WSA
was required due to six planning applications that
meet the definition of a “project” under SB 610 or
that require annexation to the City. The WSA includes
water demands (surface and groundwater) that will
occur as the City reaches buildout under its General
Plan. The WSA also considers the demands of other pumpers
in the ground-water basin.
LSCE conducted a number of tasks
relating to the ground-water supply portion of the
WSA. LSCE defined the study
area appropriate for the WSA. LSCE prepared geological
cross-sections for the aquifer system underlying the
City; summarized the hydrogeology for the south Santa
Rosa Plain Subbasin, including the relationship of
the City’s sources of ground-water supplies to the
subbasin. LSCE developed a database for purposes of
the WSA that includes production, well construction,
historical ground-water levels, and ground-water quality
data. LSCE analyzed historical and current ground-water
conditions, including ground-water production and aquifer
response (e.g., water level response of different aquifer
units of the aquifer system) based on available data
within the City boundary and also in the Santa Rosa
Plain Subbasin. This analysis also included evaluation
of areal and vertical ground-water quality characteristics
within different zones of the aquifer system and local
contamination issues that may affect future ground-water
availability. LSCE assisted with preparation of a Draft WSA, presentations
to City Council, and responses to public comments. Additionally,
LSCE assisted the City attorney with responses to comments
by an environmental organization expressing concerns
about the adequacy of the WSA. Following the public
review and comment period on the draft WSA, the final
WSA was submitted to and approved by the Rohnert Park
City Council in January 2005.
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