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Dredging the sediment will increase the depth of the creek mouth and surrounding
areas, however, will this sediment return quickly? If the sediment
does begin to accumulate, where will that occur? What can be done
to direct future sedimentation to less harmful areas?
These questions are very important City of Middleton officials. Dredging
causes a large disturbance for homeowners in the area and Middleton wants
to make sure they don't simply "treat the symptoms" of sedimentation.
Future dredging expenses could be avoided by properly researching sediment
flow at the creek/lake boundary to determine strategies for directing the
sediment.
ELCIRC
ELCIRC is
an unstructured-grid model designed to simulate 3D baroclinic circulation
across river-to-ocean scales developed by CORIE at the Oregon Health and
Science University. The program uses finite volume/finite difference
Eulerian-Langrangian algorithm to solve complex shallow water equations,
written to realistically address a wide range of physical processes and
of atmospheric, ocean, and river forcings. The program has been run
for a limited number of situations and it is unknown whether the model
with function for the small scale and freshwater environment of the Pheasant
Branch Creek and Lake Mendota.
The program requires the user to create a complex triangular grid that
describes the underwater topography of the area of study. Each node
of the grid is defined by x, y, and z coordinates. An example of
the grid used to study the Columbia River estuary is shown below.
ELCIRC can model a variety of characteristics of the area of study such
as the salinity gradient of the Columbia River:
I am currently in the process of developing an ELCIRC model for the sediment
flow in the region from the Century Ave. bridge to the mouth of Pheasant
Branch Creek and from the mouth to the Lake St. boat launch.
The ELCIRC program is very sophisticated and therefore detailed knowledge
of the area of study. Once the model is complete I will add it to
this page.
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