Geologic
Controls on Water Resources in the National Parks
| "Proper management of water
resources within National Park System units is becoming more complex
and challenging as threats to this precious resource, both internal
and external to park boundaries, increase. Planning is an essential
step in comprehensively understanding the hydrologic environment and
addressing complex water resource issues faced by many of these park
units."
-David Vana-Miller,
Hydrologist,
Water Resources Division,
National Park Service.
|
Understanding the geologic controls on water resources is critical
for wise resource management decisions when water sources are scarce
or threatened by possible contamination. USGS geologists, geophysicists
and geochemists help to provide the structural and stratigraphic
information required by hydrologists for modeling ground-water flow
and contaminant pathways.
Death Valley National Park: Developing a Geologic Framework for Ground-Water Models
Water is the lifeblood of Death Valley National Park, but there
are pressures from outside the park boundaries to develop adjacent
groundwater resources. The central Death Valley region is the area
of principal water discharge for a regional branch of an extensive
groundwater system. This system encompasses more than 15,000 square
miles in southern Nevada and southeastern California.
Pictured above: Saratoga Springs
in Death Valley. Photograph by Bruce Rogers, USGS. |
In Death Valley National Park, springs are home to numerous threatened
or endangered plant and animal species and currently provide the
only potable water sources for the park. Recent contamination of
some springs resulted in a request from the National Park Service
for science support in helping to select well sites for a new domestic
water supply.
The largest geologic and geophysical mapping effort in a single
park is focused on Death Valley. Geologic mapping and geophysical
studies are employed by the USGS in cooperation with the NPS to
determine geologic controls on spring discharge and groundwater
flow paths. The USGS used shallow seismic data combined with surface
mapping to develop a geologic interpretation of the subsurface structure.
The project is one component of a multi-agency effort to develop
a regional tectonic, geologic and hydro-geologic data model. The
Department of Energy is a also a regional partner.
Pictured above: USGS and National
Park Service employees using portable "thumpers" as
seismic sources for subsurface imaging. |
Seismic data were used in conjunction with detailed geologic mapping
to constrain the subsurface extent of highly permeable, coarse alluvial-basin
deposits that comprise the principal aquifer for the proposed water
well. Migration of potable water sources to subsurface aquifers
will enable reclamation and preservation of existing spring resources. |
