 Hydrological
and Environmental Investigation of a Mining District
Exponent staff completed a fast-track, multi-faceted hydrological
and environmental investigation of a major historical
mining district in Nevada to assess the potential environmental
impacts of reopening five open-pit copper mines. This
study involved modeling the local and regional hydrogeology
of the mining district, evaluating the effects of dewatering
and process-water pumping, predicting the water quality
in the lakes that will form in the excavated pits, characterizing
waste rock, and modeling various waste-rock and tailings
disposal options. The project culminated in a technical
document that was submitted in support of the environmental
impact statement. After an exhaustive study of the document
during the required public review period, all necessary
permits were granted. Our completion of this large-scale
effort within an accelerated 8-month schedule enabled
our client to begin mine facility construction immediately.
Delays in securing permits would have postponed construction
for 6 months until the spring thaw, costing the client
millions of dollars. |
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 Santa
Clarita Stormwater Drainage Systems Analyses The
City of Santa Clarita, California hired Exponent to
analyze its stormwater drainage system, and as this
project continues, we will also identify cumulative
downstream impacts from the City's continued growth.
Santa Clarita is located in a semi-arid floodplain that
straddles the Santa Clara River. The City has had to
adapt its regulatory and planning processes for permitting
new development to account for the changing water volumes
and water quality of the river. Because of the dry climate,
sudden storms hitting the area can cause a torrent of
water to rush downstream, increasing the risk of flood.
Exponent staff analyzed the stormwater drainage system
for deficiencies and identified flood risk areas by
blending the HEC-1 model used by the Army Corps of Engineers
with the Modified Rational Method of Analysis (MORA)
model used by the Los Angeles County Department of Public
Works. This allowed us to apply a nationally known and
proven method while meeting the particular needs of
the region we were studying. These analyses will assist
the City in identifying upstream and downstream contributions
to the drainage system requirements and will provide
justification for the allocation of funds to replace
or modify deficiencies within the system.
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