SUSTAINABILITY
BLUE CARBON PILOT PROJECT
Blue carbon refers to carbon captured in ocean and nearshore environments, assimilated as biomass and stored in
marine sediments. Blue carbon process are critical to concerns for acidification of marine areas due to increases in
atmospheric CO2. In Puget Sound, kelp, eelgrass, shellfish, and salt marsh are important elements in blue carbon
processes, ensuring productive, resilient and carbon-rich marine conditions.
The Port of Seattle, Maritime Division, is conducting a pilot project to
evaluate the ability to enhance blue carbon processes at Smith Cove:
CARBON SEQUESTRATION
Eelgrass, kelp and salt marsh vegetation sequester (or trap) dissolved
carbon at a significant rate – as much as a ton of CO per acre annually.
The Smith Cove project is expected to sequester 10 tons of carbon every
year, or the equivalent of over 1,000 gallons of gasoline combustion.
FISH AND WILDLIFE HABITAT
In addition to sequestering carbon, eelgrass, kelp and salt marsh are the
most biologically productive habitats in Puget Sound, supporting a wide
variety of fish and wildlife species, including life stages of endangered
Chinook salmon.
WATER QUALITY IMPROVEMENT
The project includes re-establishment of native oysters in Smith Cove,
with a goal to support over 1 million oysters. A single oyster siphons up
to 2 gallons of water per hour, removing particulate matter and
contaminants. Introduced shellfish would filter up to 50 million gallons of
Elliott Bay water per day.
OCEAN ACIDIFICATION REFUGIA
Acidification is one of the major threats facing Puget Sound. By removing
dissolved carbon from the water, kelp, eelgrass and salt marsh buffer
acidification, providing beneficial habitat for oysters and other pH-
sensitive species.
Portage
Bay
Lake Union
Downtown
Seattle
Broad St
15th Ave W
Elliot Ave W
Denny Way
S. Dearborn
Elliott Bay
Terminal 91
Blue
Carbon
Pilot
Project
4th Ave
Harbor Ave SW
Airport Way S
90
5
The project site, which is
between Pier 91, Elliott Bay
Marina, and Smith Cove Park,
includes all of the characteristics
necessary for the project:
• Protected from wave energy
• Appropriate depths
• Suitable substrate
• No conflict with existing uses
• No overwater structures
• Accessible for interpretation
and public education
www.portseattle.org
Email and Text Updates
Sign up for updates at our web page
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Port of Seattle
P.O. Box 1209
Seattle, WA 98111
www.portseattle.org
Printed on recycled paper using soy based ink. 04/2018
#bluecarbon
WAVE/CURRENT ATTENUATION
As sea level rises and storms intensify, our shorelines are
becoming increasingly prone to erosion. Kelp, eelgrass,
shellfish beds, salt marsh and riparian vegetation play
an important role in stabilizing the shoreline,
dissipating energy, and storing sediments.
SUSTAINABILITY
The project does not include structures or other
components which require maintenance; if successful, it
will be self-sustaining. The project also includes the
potential for harvesting shellfish biomass to create
marine-based organic compost for use in the Port's
shoreline parks and riparian habitats, helping to
maintain their "Salmon-Safe" certification.
SMITH COVE “BLUE CARBON” PILOT PROJECT
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100' offset f rom dock
Buoy
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Elliott Bay
Marina
Pier 91
Elliott Bay
Future Smith
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Eelgrass
(12.42 acres)
Canopy Kelp
(7.03 acres)
Intertidal Shellfish
(4.91 acres)
Riparian
(0.63 acres)
1,257,000
1,257,000
1,258,000
1,258,000
233,000
233,000
234,000
234,000
235,000
235,000
0 100 200 300 400
Feet
1 inch = 125 feet when printed at 18" x 24"
I
Document Na me: Terminal 91 Ba thymetry an d Habitat Areas - 2017-09-2 0 Date Sav ed: 9/20/201 7 3:18:06 PM
CoordinateSystem: NAD 1983 StatePlane Washington North FIPS 4601 Feet
Project Boundary
Park Area
!(
Stormwater Outfall
Port Facility Boundary
WA-DNR PMA Land Boundary
Port Parcel Boundary
King County Parcel Boundary
Habitat Class
Canopy Kelp
Eelgrass
Intertidal Shellfish
Riparian
Riparian vegetation
(> +12’ MLLW)
Shellsh beds
(+1’ to -5’ MLLW)
Eelgrass
(-1’ to -12’ MLLW)
Kelp
(-12’ to -24’ MLLW)
Marsh Plants
(+12’ to +8’ MLLW)
PROJECT OVERVIEW
Step 1: Plant and install blue carbon
enhancements:
• Kelp
• Eelgrass
• Shellfish beds
• Intertidal salt marsh
• Shoreline/riparian vegetation*
*Size/scope/schedule TBD
Step 2: Monitor project over time:
• Water Chemistry (pH)
• Carbon sequestration
• Beneficial habitat changes
Step 3: Report results
The blue carbon project team includes staff from
the Port, Puget Sound Restoration Fund, NOAA,
City of Seattle
, UW and Grette Associates.
2018
2019
Baseline surveys
(March-April 2018)
Eelgrass test plots
(May-June 2018)
Completed project
design (October 2018)
Kelp substrate placement
(December 2018)
Shoreline restoration (TBD)
Long term UW study (TBD)
Interpretive signage
(2019)
Install “blue carbon” features
(Jan-May 2019)
Kelp test plots
(April-May 2018)
Shellsh test plots
(July-August 2018)
Future
blue carbon
a
ctions:
20
20
20
21
20
22
Growth and maturation
(2020-2023)
