Posted on September 3, 2020 at 11:55 AM by Allan Warren
Cold, clear groundwater fills the
newly excavated side channel at the South
Prairie Creek Preserve restoration site. The
influx of groundwater is critical for keeping
water temperatures from reaching levels
lethal to salmonids during the summer. In
the background, logs are staged for the more
than 100 structures that will be placed in
the banks and on the floodplain to provide
roughness and help protect against erosion.
The salmon habitat improvement
project at the District’s South Prairie
Creek Preserve reached several
important milestones over the past
few months. Demolition of the former
dairy buildings concluded in late spring,
at which point work transitioned to
the north floodplain. First, several
large patches of poison hemlock were
removed and buried to prevent spread
of this harmful plant. Then a half-mile
long side channel was excavated. Using
the depression left by a relic side
channel as a guide, this excavation
daylighted cold, clear groundwater that
quickly filled the new stream. More
than 100 large wood structures have
been installed on the floodplain and
in the streambanks, followed by the
installation of three channel-spanning
structures in the mainstem of South
Prairie Creek.
The bulk of construction is scheduled
to wrap up by the end of summer, after
which the focus will shift to completing
restoration of riparian and floodplain
plant communities across more than 36
acres.