San Juan Islands Conservation District Re-Connects Tidal Flow
and Restores Beach Vegetation at the Port Stanley Lagoon
Port Stanley Lagoon, Swifts Bay, Lopez Island
On July 2, 2006
San Juan Islands Conservation District (SJICD) completed a
three-year effort to improve water quality in the Port
Stanley Lagoon on Lopez Island. Installation of a new,
hydraulically-operated tide gate at the lagoon outlet in
June 2006 restored daily tidal flow into the lagoon for the
first time since the early 1960s. With the completion of
the project, SJICD and its project partner the San Juan
County Department of Public Works (DPW) expect to see not
only improvement in the lagoon water quality but also
improved wildlife habitat and reduction in flooding during
severe winter storms.
It replaces a tide gate that was installed to block tidal
flow into the lagoon outlet in the 1960s, the lagoon
gradually filled with sediment so that it became so shallow
that only a stagnant puddle remained by late summer. In
addition, without continuous tidal flushing, the tide
gate’s outfall pipe on the beach sometimes filled with
sand, preventing winter storm runoff from draining
properly.
At the request of the lagoon owners, the Mattson Family,
SJICD received a US Fish and Wildlife Service grant in 2003
to complete an engineering study to evaluate ways to
restore some degree of tidal exchange while improving the
winter drainage and flooding situation. After completing a
hydraulic modeling study and field-testing, SJICD presented
several options to local community members. The Mattsons
and other neighbors favored a plan to allow partial tidal
exchange into the lagoon, but only up to a level that would
not impact lawns, drain fields, and other property.
SJICD next won a grant from the Washington Department of
Fish and Wildlife to design and implement this plan. The
plan’s first task included dredging the outlet channel and
modifying the beach outfall pipe, which were completed in
August 2005. The second task involved fabricating and
installing a new type of tide gate that would open and
close at pre-set tidal elevations. This type of tide gate,
which is only the third installation of its kind in
Washington State, works like a screen door. The force of
water draining from the lagoon on a falling tide opens the
“door.” The resistance in the door’s hydraulic piston keeps
it open as salt water flows back into the lagoon on the
next rising tide. When the tide reaches a specified height,
it trips a float valve, which releases the pressure in the
piston and allows the door to close again.
DPW’s Lopez Island road crew installed the new tide gate in
June 2006, during which the upland portion of the beach was
disturbed and compacted by heavy machinery. Tom Slocum, our
Conservation District Engineer suggested planting dune
grass to restore the original beach vegetation and complete
the project. Our SJICD staff including Ron Zee, Bryan
Cornelius, Danna Kinsey, and Steve Hussey along with DPW
Lopez Island Road Crew Jerry and John spent April 19, 2007
planting 700 plants to cover the 2500 square foot site. We
planted 500 Dune Wild Rye (Leymus mollis) and 200 Beach Pea
(Lathyrus maritimus) from 4th Corner Nursery in Bellingham.
Plant choice was based on species currently present along
undisturbed areas of the beach and from suggestions by
beach restoration specialist Jim Johannessen of Coastal
Geologic Services Inc. Funding for this project was
provided by Ducks Unlimited as well as the San Juan Islands
Conservation District and San Juan County Public Works.
The tide gate is managed by San Juan County Public Works
Lopez Road Crew and can be viewed inside a grated vault
along Port Stanley Road, Lopez Island. For questions about
the project contact us at (360) 378-6621.
Press Release by D. N. Kinsey, San Juan Islands
Conservation District
UPCOMING PUGET
SOUND CONSERVATION DISTRICTS VIDEO PROJECT (Filmed Summer
2008): Public information videos (series). Produced in
conjunction with Bartlett Group, Seattle.
Tour of conservation/environmental protection projects in
King County (Seattle & vicinity), as well as in various
other locations throughout Puget Sound including the Port
Stanley Restoration on Lopez Island.
The video highlights the work of Puget Sound Conservation
Districts in various efforts to promote agriculture, help
restore saltwater beaches damaged by seawalls, protect
salmon-bearing streams, etc.
Visit: http://www.kempcomm.com/environment.html