HomeMy WebLinkAboutOriginal Townsite Block 7 - Eelgrass Survey Quincy Street Cannery 2001.06.23June 61 2001 Eelgrass Survey
Quincy Street Cannery Eelgrass Survey
For an Overwater Deck Structure
Port Townsend Bay, Tributary to Admiralty Inlet
SW % Section 01, TS 30 N, R01W
WRIA l7.MARI - WDFW Log Number 00E7833.02
Prepared for:
Mr. Kevin Harris
1819 3l't Street
Port Townsend, Washington 98368
Prepared by:
Kenneth M. Brooksr Ph.D
Aquatic Environmental Sciences
644 Old Eaglemount Road
Port Townsend, WA 98368
Phone (360)732-4464
June 23,2001
Quincy Street Cannery Eelgrass Survey
For an Overwater Deck Structure
By letter dated April24,200l,the Washington State Department of Fish and Wildlife
(WDFW) required completion of an eelgrass survey adjacent to the Quincy Street Cannery prior
to issuing a Hydraulics Project Approval for adding an overwater deck to the structure.
Requirements stipulated in WDFW's letter included the following:
" Survey to be completed between June and October;
. Perimeter of the eelgrass is to be mapped and the density of eelgrass within the bed
documented by sampling no fewer than 6 0.25 meter square quadrats within both the
center and along the shoreward edge of the bed;
. Bed density to be expressed as turions/0.25 m2;
. The exact location of the edge of the eelgrass bed relative to the waterward edge of the
proposed deck and the existing building mapped to include the depth of the eelgrass bed
edge;
All eelgrass between the existing building and the previously eelgrass bed to be
documented.
Authors qualifications. The author has a Ph.D. from the University of Washington, College of
Ocean Sciences and Fisheries. He was the director of the Technical Fisheries Program at
Peninsula College fuom 1992 until 1997. His research expertise lies in the study of animals
inhabiting marine sediments with emphasis on invertebrate community structure and the
influence of disease and pollution on individuals and populations of organisms. In addition, the
author owns a research laboratory in Port Townsend, Washington and is a qualified Level I and
Level II wetland consultant in Clallam County. The author has been conducting eelgrass surveys
in compliance with Washington State Department of Fish and Wildlife Hydraulic Permit
Approvals since 1991. A curriculum vita is available on request.
Previous surveys. Bonar (1998) did not document a continuous eelgrass meadow at this site as
implied in WDFW (2001). Bogar (1998) documented three small patches of eelgrass whose
dimensions were given as l8 ft2, 10 ft2 and 3.0 ft2. The patches lay 18' and27'from the based of
the Quincy Street Cannery foundation. Zoostera marino and Z. joponica turion densities were
not included in Bonar (1998).
June 6, 2001 survey. This Year 2001 survey was conducted between 0830 and 1245 hours on
June 6, 2001 during a predicted low tide of -1.7' MLLW occurring at 1055 hours. Consistent
with the previous report, eelgrass at this site was restricted to several small patches that are
mapped in Figure (2). Figure (1) shows the relationship between the largest (Patch E covering
9.5 m2), densest (430 + 39.6 turions/m2) and closest to the deck's shadow (27') of these patches.
Turion densities in the three patches covering sufficient area to be evaluated are provided in
Table (1) along with the location and coverage (in square meters) of each patch. Turion density
in patch "E" was measured in the densest part of the patch. The number is not representative of
2
the entire patch, which is irregular. A complete set of tidal datawas submitted with Bonar
(199S) and is not repeated herein.
Table l. Summary statistics for patches of eelgrass observed on the shores of Port
Townsend Bay in the vicinity of the Quincy Street Cannery on June 6' 2000. Turion
density is expressed in numberlm".
Patch (Figure 1) Area (m2)
A 1.0
B 5.7c 1.9D 2.8E 9.5
-Tidal elevation Turion count (+ 95% CI on mean)
67.2+ 27.6
-1.5'MLLW
-1.0'MLLW
-0.7'MLLW
-0.5'MLLW
+0.5'MLLW
147.2 + 44.8
430.0 + 39.6
Flags outlining proposed deck
Patch E. The largest and closest ofthe
eelgrass patches adjacent to the Quincy
Street Cannery
X'igure l. Relationship between eelgrass patch "E" and a flagged outline of the proposed
overhanging deck at the Quincy Street Cannery.
3
Cannery Building
.r- .:..,.
Extent ofdecks shadowing effect
-MLLW
*
tt'{'t
lIt
l0'
(<t)
26',
'{ata{)
l t Itlt{>tt>
'.I''{'I
38',
47',
57 Dc
B
@r
Figurc 2. Relationship between the proposed deck at the Quincy Street Cannery and
patches of eelgrass (Zoostera marina and Z. japonica) observed on June 6, 2001.
Figure (3) describes the relationship between shadows cast by the existing Quincy Street
eannery, the proposed deck and the bottom. The deck will shade the ground only during that
period of time when the sun is approximately overhead. Shortly after the sun passes its zenith,
ihe ground will be shaded by the existing canneries roofline. A little basic geometry indicates
that the deck's shadow will extend 17.0' east from the Canneries foundation before it is eclipsed
by the roofline. The red line describes the maximum eastward extent of the deck's shadow
4
before the suns rays are blocked by the
roofline. The proposed deck's shadow
will not reach any of the patches of
eelgrass.
As described in Bonar (1998)
and shown in Figures (l) and (4a), the
rocks covering the substrate above ca.
+1.5' MLLW, in front of the cannery,
supported a patchy growth of
rockweed (Fucus ^q,p.) and sea lettuce
(Ulva qp.). Occasional fronds of
Laminaria cf, saccharina were also
observed with more frequent Ulva as
drift algae. Except in the morning, the
deck and/or building will shade the
macroalgae growing on the canneries
foundation and at its base (Figure 3).
There is a deeper boardwalk (deck)
located north of the cannery. Figure
(4b), taken under the existing deck,
suggests that while the canneries deck
will shade the bottom and likely
diminish the growth of macroalgae, it
will not
extinguish these plants. There is a ca.
10 percent covering of Ulva sp.
growing in the reduced light
under the existing boardwalk.
tDP of FnP.ta t''.-o
.fi
PllclFatED
OGCl<
'rrfl.ttlrrt lo.2o|
td.rr Htttl
ne4t l:vt
rrJ
Closcst eclgrass is 27' cast of thc founclation
Figure 4a. Macroalgae growing on adjacent rubble and on the foundation of the Quincy
Street Cannery in Port Townsend, Washington on June 61 2001. 4b. Macroalgae
growing under an existing boardwalk - deck located just north of the Quincy Street
Cannery.
5
Figure 3. Relationship between the Quincy Street
Canneries roofline, the proposed deck and the
intertidal area adjacent to the structures.
Summary and recommendations. This project will not likely effect the existing patches of
eelgrass growing at tidal levels < +0.5' MLLW at distances ) 27' from the foundation wall.
It is unlikely that eelgrass will move higher on this beach where it might be affected by the
deck's shadow for several reasons:
Suitable sandy substrates extend only another foot or so shoreward. Above that, the
substrate consists of rock and concrete rubble that does not provide suitable substrate
for eelgrass.
Eelgrass is seldom encountered at tidal elevations > + 1.0' MLLW in Puget Sound.
The patch closest to the armored foundations and bulkheads along this stretch of Port
Townsend's waterfront are already growing above this normal upper limit.
Bulkheading has armored the beach in this area and southeast storm waves dissipate
their energy on these structures - scouring the adjacent sediments. A significant storm
would likely uproot any eelgrass growing higher in the intertidal. In fact, I suspect that
a southeast gale would likely uproot some of the patchy eelgrass growing at this site.
Shadowing from the deck during the late morning and early afternoon, when the sun is near
its zenith, will likely diminish production of several common algae species growing on the
Quincy Street Cannery foundation and rubble laying at the base of that foundation. The
following actions are recofllmended to mitigate for that loss:
1). The deck should be constructed of low aspect ratio aluminum grating to allow
maximum penetration of light. The orientation of the likely rectangular openings should be
north and south. Light will penetrate under the deck during summer mornings, regardless the
grating's orientation. The north south orientation is stipulated to improve light penetration
during the winter when the sun's arc is not overhead, but displaced to the south.
2). A series of SolatubesrM could be installed behind the false front on the east end of the
Cannery and fiber optics used to transport the energy under the deck. The SolatubesrM would
not be visible behind the fagade and they would function best in the afternoon when the
building is shading the benthos.
3). The concrete rubble lying at the base of the foundation is likely functioning to help
stabilize substrates in this high-energy area. Removal of this rubble is not recommended
because it would displace the algal resource growing on it and the resulting substrate instability
might result in loss of the existing eelgrass. However, there are several pieces of steel pipe
and other unsightly garbage that should be removed from the area for aesthetic reasons.
4). There were several derelict creosote treated stub piling at this site. These piling are
providing good habitat for Balanas nubilus and other barnacles plus a host of amphipods.
However, knowing WDFW's passion for removal of these valuable habitat features, the
applicant should consider voluntarily cutting them off below the mud line. They are
6
"stovepipes" and could not easily be pulled. The excavations will fill naturally during the first
storm at this high-energy site.
This project should have minimal to no impact on the natural resources of Port
Townsend Bay regardless of any requirement(s) for mitigation. In part, the recommendations
made above will ameliorate any potential for structural damage to the deck during exceptional
storm events and will improve the aesthetics of the area while insuring that there is little or no
diminution of the small macroalgae resource that might be minimally compromised by partial
shading from this project.
Sincerely,
Brooks
Aquatic Environmental Sciences
7