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Topic Name: The upstream effects of Searsville dam and its removal
Category: Geo sciences & technology
Research persons: Christopher Heppner
Location: Hydrogeology Program,Dept. of Geological and Environmental Sciences,Stanford University,Stanford, CA 94305-2115, United States
Details
Construction of Searsville Dam in the 1890s created a biotically
important lake in a watershed with a high sediment load. Siltation has
now reduced the capacity of the lake by about 90 percent. With a grant
from the National Science Foundation, PhD student Chris Heppner is
studying the effects of Searsville Dam, and its possible removal, on the
hydrologic functioning of the upstream area near the lake, including the
wetland on the southern end. Hydrologic changes expected to occur after
dam removal include a drop in the local water table, decreases in soil
saturation near the lake, and changes in evaporation rates, groundwater
recharge rates, and interactions between surface water and groundwater.
Chris is working with professor Keith Loague.Chris’s study combines the comprehensive Integrated Hydrology Model (InHM)
with a sediment transport model so that he can model streamflow, runoff,
and sediment transport through the 14-square mile watershed to
Searsville Lake. Chris is tailoring the model with existing data and
also new measurements from an array of nine stations (4 within JRBP)
where he monitors soil moisture, rainfall, and soil water potential (the
pressure necessary to extract water from the soil). One can imagine his
model as a mesh draped over the watershed, with the hydrologic processes
in each cell interacting with those of neighboring cells.
Chris’s goal is to characterize the hydrologic history of the
watershed from the pre-dam period to the present, and then extend the
model to predict what would happen if the dam were removed. He will ask
questions such as: How quickly will the water table respond to dam
removal? When will it stabilize? Over how large an area will changes
occur? He will investigate similar questions regarding runoff patterns,
evaporation rates, and other hydrologic and geomorphic processes.
About Researchers:
Christopher Heppner
PhD Candidate
Hydrogeology Group
Dept. of Geological and Environmental Sciences
Stanford University
Background:
Education:
B.S. in Geology/Biology, Brown University, 1998
Work Experience:
Intern, Meridian Exploration Corporation, Pittsburgh, PA, 1998
Associate, Bridge Scour Project, USGS Pennsylvania District, 1999
Teaching Assistant, Dept. of Geological and Environmental Sciences, Stanford University, 2000-2004
Hydrologist, Unsaturated Zone Flow Project, USGS, Menlo Park, CA, 2003-2005
Funded:
The area now included within the Jasper Ridge Biological Preserve has
been used for scientific studies since the opening years of Stanford
University. Since that time, the scientific contributions of JRBP have
reflected the capacity of scientists and students at Stanford and other
institutions to envision, conduct, and interpret groundbreaking research
involving a range of academic disciplines. Many current studies draw on this
legacy of research, while others address new questions and problems. In
total, 165 dissertations and theses have involved research at JRBP, and
since 1965, 335 publications have reported research at JRBP. Students have
submitted over 400 papers resulting from studies at JRBP.
The Preserve is widely recognized as the site of discoveries that have been
important both to fundamental scientific questions and to society. For
example, Professor Paul Ehrlich's discoveries about Bay checkerspot
butterflies demonstrated the unique value of long-term research in ecology,
and helped foster federal programs to fund such studies. The importance of
long-term research and monitoring is now widely accepted. A number of
scientific publications resulting from research at JRBP discovered
ecological patterns so significant they stimulated hundreds of related
studies. Many of these papers by Professors Christopher Field and Harold
Mooney established principles that are the foundation of the largest
research program now at JRBP, a study of ecosystem responses to a suite of
environmental changes that are occurring globally. A long-term monitoring
project by Professor Deborah Gordon’s lab has mapped the invasion of
Argentine ants and used "before and after" comparisons of
ecological communities in the path of the invasion to better understand the
ants’ impacts. These studies and others demonstrate the intrinsic
connection between JRBP’s missions in research and conservation.
Jasper Ridge also contributes broadly in that it is open to any qualified
investigator who proposes studies that are consistent with the Preserve's
mission of research, education, and long-term resource protection. Proposed
studies are evaluated on whether they:
- Contribute to fundamental scientific knowledge through
well-designed experiments whose results are intended for peer review and
dissemination.
- Contribute beyond the borders of JRBP by being part of
inter-site comparisons or larger surveys.
- Minimize impacts to JRBP ecosystems and to ongoing
experiments.
- Are especially suited to JRBP in some way, e.g. because
of site history, specific resources, ongoing studies, or links with
JRBP’s education or conservation missions.
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