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DESCHUTES
RIVER ESTUARY RESTORATION |
| Deschutes
River Estuary Restoration Feasibility Study
| | The
goal to this study is to evaluate the feasibility of restoring the Deschutes River
Estuary (Capitol Lake) as an alternative to managing a lake. Earth Design Consultants,
Inc. is sampling biological and physical variables from multiple estuarine community
types of several reference estuaries. The environmental variables include: elevation,
sediment grain size/characteristics, and salinity. We
used multivariate statistics to develop empirical relationships between estuarine
plant community types and the environmental variables. We then used these relationships
to predict the likely outcome of restoration scenarios in the Deschutes River
Estuary using the USGS Delft3/ SWAN models. Rather
than using indicators or single variable approaches to evaluate restoration success,
we used the relationships between communities and measured environmental gradients
developed during this project to track likely restoration trajectory paths through
multidimensional state space. |
Capitol
Lake (Olympia, WA) |
Background In
1951, a dam was constructed across the southern portion of Budd Inlet (Olympia,
WA) creating freshwater lake in what was once a tidal wetland. Since the dam was
constructed, Capitol Lake has been plagued with water quality and sedimentation
issues. Consequently, the Capitol
Lake Adaptive Management Plan (CLAMP) Steering Committee initiated a project
to study the feasibility of restoring the estuary. |
 | What
is remarkable about this project is that it involves evaluation of several restoration
alternatives using a high-tech modeling tool. Costs and benefits of the various
restoration alternatives, as well as a "do nothing" alternative, will be evaluated
and restoration performance goals will be set before any on-the-ground restoration
action is taken. The tool being used is a sophisticated model developed by U.S.
Geological Survey (Menlo Park, CA) which predicts sediment transport, water velocity,
and salinity patterns in the estuary to be restored. The modeling tool uses river
gage, tidal, wind, bathymetry, sediment, and salinity data as input variables.
| | Using
the estuary's,underwater topography (morphometry), or shape of the estuary basin,
the computer model describes patterns of sediment transport, salinity, water velocity,
and inundation patterns modeled under different river flow and restoration scenarios.
The model predicts where sand and mud flats will likely occur and expected erosional
patterns associated with channels and different flow regimes. |  |
| Earth
Design Consultants, Inc. field crews visited nearby estuaries to sample plant
and animal communities and measure key environmental variables at these reference
estuaries. The field data were used to develop statistical relationships describing
the association of plant and animal communities with the environmental factors
which organize those communities. These statistical relationships were then used
in the model to predict what communities were likely to occur under each of the
potential restoration scenarios. This information will be used by managers to
evaluate each of the scenarios. In this suite of studies, field data and computer
modeling will be used to evaluate alternative restoration plans for the removal
of a dam before removing one brick. Models are useful tools for examining the
influence of site-specific and landscape variables on restoration projects. |
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Reports
and Publications Executive
Summary Figure
20 Predicted Sediment Textures Figure
25 Predicted Habitats Addendum:
Benthic Invertebrate Study | Contact Information
Wetland
& Watershed Assessment Group Earth
Design Consultants, Inc. 230 SW Third St., Suite 212 Corvallis, OR 97333 (541)
757-7896
(541 757-7991 FAX http://www.earthdesign.com |
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