Bringing Life to the Shoreline AT THE FREMONT BRIDGE
Alicia Kellogg
MLA Capstone Project, June 2021 1
Introduction
The Fremont Bridge is one of six bridges spanning the Ship Canal in Seattle between Puget Sound and Lake Washington. It was constructed in 1917 to span the then newly-constructed Lake Washington Ship Canal, a modern engineering marvel built to make waterbound passage between Puget Sound and the interior fresh water bodies more tenable. By digging a canal from the Sound to Lake Washington, Seattleites completely changed local hydrology and “cut” the city in two, thereby creating the need for bridges in order to cross the waterway.
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Today, the Fremont Bridge is a colorfully painted neighborhood icon, one of the few human-scale bridges for pedestrians and bikes alongside car and bus traffic. Its proximity to the Burke Gilman, the South Ship Canal trail, and the Cheshiahud Lake Union Loop make it a popularly traversed bridge by commuters and recreationalists alike. Interesting features at this site include fenders for boat traffic, brand new bioretention cells installed nearby at the northern base of the Aurora Bridge, and small portions of the bank that are armored with rip rap instead of concrete walls.
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Project Origins
This design project was inspired by an existing research effort called the Sweetgrass Restoration Project, which focuses on strategies that create living shorelines in urban waterways in order to increase salmon habitat.
Concept Development SWEETGRASS RESTORATION PROJECT
LIVING SHORELINES
PROJECT LOCATION
FREMONT BRIDGE
+ = LIVING SHORELINES AT FREMONT BRIDGE
Final Project Concept
BRINGING LIFE TO THE SHORELINE AT FREMONT BRIDGE 4
FREMONT BRIDGE
Design Question What design interventions can reveal, connect, and enhance life to the shoreline at Fremont Bridge?
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FREMONT CANAL PARK
GOOGLE PARK VIEW
EVANSTON PLAZA
0.5-MIL E
WALKS HE
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G BRID T N O
FREM
BUR
I A BR
DGE
OR AUR
KE-G
ILMA
N TR AIL
project site passage places of rest 6
Rest-Passage Analysis
Due to its proximity to the Burke-Gilman Trail, the project site has a narrow, elongated quality that encourages passage rather than rest. This diagram shows how passage-dominant the surrounding areas along the shoreline are to the east and west of the site.
To the east There are a few small spaces available for rest to the east of the site, but all are liminal and insubstantial. Fremont Canal Park is difficult to recognize as a park because it is really just a long, narrow stretch of lawn between the trail and the canal. There are a few formal benched areas for sitting;
during sunny weather, residents can be seen picnicking on blankets or lawn chairs that they’ve brought from home. Google Park View and Evanston Plaza are both terraced seating areas between buildings that are popular when it’s sunny out, especially for local workers during lunch breaks.
To the west Gasworks Park is just outside the halfmile walkshed to the west. Between this project site and Gasworks, there are no formal opportunities for rest.
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salmon migration route elevated water temp and DO issues
R IVE MAMISH R M SA
artificial nighttime light issues
PUGET SOUND
FREMONT BRIDGE
LAKE WASHINGTON
LAKE SAMMAMISH
DA R RIVER
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QUAH CRE SA EK
IS
CE
Salmon Migration Issues
The anadramous salmonid species that migrate through the Ship Canal are Chinook, coho, and sockeye. Each of these salmon runs originates in either Issaquah Creek or the Cedar River, both of which are increasingly urban the closer they get to Puget Sound. The highly developed nature of these migration routes approaching Puget Sound results in increasing existential threats to juvenile salmonids.
from predators, and healthy riparian vegetation that provides dapple shade for camouflage and food inputs in the form of terrestrial insects. The Ship Canal is the final urban gauntlet that outmigrating juveniles must pass through before reaching the Sound. Suboptimal habitat conditions include armored shorelines, a proliferation of overwater structures, and a high density of invasive predators.
Migratory salmon have relatively straightforward habitat needs in fresh water. Outmigrating juvenile salmonids require: cool, clean water with plenty of dissolved oxygen, stream channel complexity to provide cover 9
CONCRETE WALL Armoring that exte Ship Canal ends on
BURKE-GILMAN TR
A popular urban tra cyclists, skaters an proximity to this tra
Existing Site Conditions 10
ends through most of the n the west side of the bridge.
RAIL
ail for walkers, runners, nd commuters, the site’s ail makes it highly visible.
CREOSOTE FENDERS Boat fenders create a uniquely protected shoreline, suggesting site boundaries to the east, west, and in-water. They also provide opportunities for anchoring and containment.
DEGRADED VEGETATION Patches of weeds and non-native plants contribute to the site’s lack of identity and present an opportunity for urban restoration.
RIP RAP Rip rap creates a gradual, eased-slope shoreline compared to the concrete walls that dominate the rest of the canal.
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Deriving Design Principles
Proposed Improvements
Existing Conditions
Salmon
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Humans
Creosote fenders leach toxins into the water
Armored shorelines eliminate places to hide from predators
Degraded vegetation attracts fewer terrestrial insects as food source
No ways to interact with or understand urban ecological processes
Narrow or limited places for rest, relaxation, and observation
Homogeneity along trail, no unique site identity
Remove toxins to improve water quality
Add complexity to provide protection from predators
Install native plants that mimic riparian conditions
Create opportunities to increase ecological literacy
Create places to rest rather than just passing through
Build a sense of place that is congruent with neighborhood
Design Goals Create habitat for salmon (and other urban wildlife) that provides the provide protective
mimic riparian
habitat
conditions
functions of natural riparian systems Create “habitat” for humans to provide a place of rest and encourage them to slow down and pay attention to urban
create places
build a sense
to rest
of place
waterways and urban wildlife Reveal, heal, and highlight the connections between water and land,
increase ecological
improve water
literacy
quality
city and nature, human and animal
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6 10 9
Schematic Design
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8 5
8 4 9
1
2
3 9 6 7
10
5
0 14
100
200
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restored plantings
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exclusionary fencing
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sidewalk art
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live salmon count sign
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interpretive signage
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places of rest
of place
for salmon
habitat mats
build a sense
to rest
for humans
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create places
literacy
heal, and
floating wetlands
increase ecological
conditions
Create habitat
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mimic riparian
habitat
Create “habitat”
gabion fender
provide protective
quality
Reveal,
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improve water
bridge bioretention
connections
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highlight
10 welcome arch
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Kit of Parts
The Fremont Bridge is a unique site, but its individual components are not uncommon to urban waterways. This project’s schematic design can be broken up into a kit of parts where each design intervention addresses site conditions that may be found in other parts of the Ship Canal, Seattle, or any other similar urban site. The ultimate goal of this site design is to create a whole, cohesive site with its own identity - examining the specifics of each intervention can help understand how they will work together to create a complete and distinct site.
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Gabion Fenders
A double wall of 39” tall gabions will help to break wave action, allow walking access for floating wetland maintenance, and create habitat for fish, insects, and aquatic plants.
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Floating Wetlands
Low-tech floating wetlands made out of readily accessible materials attract terrestrial insects and help improve water quality. Modular and small in size, these units can be installed and maintained easily.
Create habitat for salmon
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TENSAR CAGE
Limits fowl browse
EMERGENT PLUGS Juncus tenuis Eleocharis palustris Schoenoplectus acutus
TENSAR LID PANEL
Compacts/contains substrate
PUMICE BRICKS Flotation element
WOODSTRAW
Growing substrate for emergent plugs
TENSAR CRIB
Lightweight and flexible, contains the substrate and allows plants to grow
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Create habitat for salmon
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Habitat Mats
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Partially-submerged envelopes of tightly-gauged coir fabric wrapped around woodstraw help soften the shoreline without disturbing existing conditions.
Restored Plantings
Beautiful native plantings become an aesthetic feature for humans and functional habitat for terrestrial insects. Woody evergreen plants help screen and fence access to the water for safety. Desired Plant Qualities SCREENING
• Prevents unsafe access to water • Discourages litter
ATTRACTIVE
• Contributes to site character • Encourages rest
NATIVE EMERGENT PLUGS Juncus tenuis Eleocharis palustris Schoenoplectus acutus
• Attracts terrestrial insects • Minimizes maintenance needs • Grows well with other natives
Planting Palette
COIR ENVELOPE
Compacts/contains substrate
WOODSTRAW
Growing substrate for emergent plugs
LUMBER FRAME
Provides rigidity and flotation
Evergreen Huckleberry Vaccinium ovatum
Dull Oregon Grape Mahonia nervosa
Baldhip Rose Rosa gymnocarpa
Nootka Rose Rosa nutkana
Salal Gaultheria shallon
Sword Fern Polystichum munitum
COIR ENVELOPE
Compacts/contains substrate
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Exclusionary fencing that reaches all the way to the ground has a small enough gauge to let juvenile salmonids through, but not their predators like northern pikeminnow, smallmouth bass, or largemouth bass. Juvenile Salmonids baby Chinook
baby Coho
Sidewalk Art
Permanent illustrations painted onto the Burke-Gilman indicate entry to the site and break up trail monotony. Painted juvenile salmon approach from the east while spawning adults approach from the west, highlighting the salmon migration that usually goes unseen.
Create habitat for salmon
Exclusionary Fencing
Excluded Predators Northern pikeminnow
Smallmouth bass
Largemouth bass
Approaching from the west
Approaching from the east
Create “habitat” for humans
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Live Salmon Count Sign
Referencing the pedestrian/bike count on the Fremont Bridge above, this live digital sign will indicate important real-time information about what’s happening in the water.
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Interpretive Signage
Educational signage will show the relationship between urban stormwater and water quality, and why our awareness about urban wildlife is important.
URBAN WILDLIFE Great Blue Heron
Create “habitat” for humans
Cormorant
Beaver
Salmon
SALMON CAM
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Places of Rest
Pull-outs along the Burke-Gilman with toadstool seats reinforce the shoreline shape and verticality while encouraging people to slow down and pay attention to the landscape before them.
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Welcome Arch
Arch-shaped art installations at either end of the site indicate entry into a distinct space, plus they create photo opportunities of the iconic bridge behind.
Create “habitat” for humans
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Bridge Bioretention
Stormwater collected by the bridge above is piped into beautifully-landscaped bioretention cells that recall the plant palette and design of the Aurora Bridge bioretention. Their shape helps extend the shoreline back towards land while creating a pocket of space for people to gather and rest. Painted lines on the pavement help show the unseen flow of water through underground pipes, revealing the obscured stormwater management practices.
CONTRIBUTING AREA
Stormwater runoff from the bridge on-ramp gets piped to the biortention for filtration
Reveal, heal, and highlight connections 22
DOWNSPOUT
Directs stormwater runoff into bioretention cells
UNDERGROUND PIPE
Filtered stormwater gets piped underground and drains to the Ship Canal
BIORETENTION CELLS
Stormwater flows through terraced bioretention cells, filtering out pollutants
CORTEN STEEL
Matching materiality to the Aurora Bridge bioretention cells helps add continuity with surrounding landmarks
Enhancing Salmon Habitat
HABITAT MATS
NATIVE PLANTS
FLOATING WETLANDS
EXCLUSIONARY FENCE GABION FENDER 23
Enhancing Human “Habitat”
SIDEWALK ART
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INTERPRETIVE SIGNAGE
PLACES OF REST WELCOME ARCH LIVE SALMON COUNT SIGN
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Notes From the Designer
I have lived in Fremont for several years, and this site is near and dear to my heart. I have seen great blue herons, cormorants, bunnies, and once I even saw a beaver(!) at this site. I have stopped to watch the bridge open with other passers-by, snapping the picture you’ll see on the back cover of this booklet. Designing this capstone project has been a wonderful opportunity for me to envision what I want my neighborhood to look like.
Discussion Many of the opportunities at this site created unique design challenges. While the inclusion of- and proximity to- the Burke Gilman meant a lot of foot traffic 26
and high visibility, it was also important to me to make sure the trail remained unobstructed and accessible, which was diffucult with limited site width. Additionally, the long, narrow shape of the area resulted in a site design whose features are best understood at a crosssection rather than longitudinally, which does no favors to the human experience. Deciding to design a “kit of parts” was fraught for me; I think the failure of a lot of urban green stormwater solutions is this idea that a universal design could miraculously solve all urban environmental woes. The green stormwater infrastructure projects I have been a part of have required a high degree of customization to be effective, and
seem to resist standardization. I didn’t want to imply universality with a kit of parts, but I did want to suggest that my design interventions could be launching points for solving problems in similar contexts. I tried to avoid designing too specifically and instead focused on the broad strokes of how intervention ideas could be used as part of larger design goals.
Conclusion A challenge of any site design that attempts to incorporate ecological improvements is that nature isn’t something that can be modularized. Ecology follows systems, connections, and relationships, and doesn’t easily fit
While most of the design interventions in the kit of parts are infeasible due to funding, bureaucracy, or pure physics (apologies to any fans of the gabion fender!), there are projects being implemented today that have already pushed the envelope regarding design, collaboration, and green stormwater infrastructure. The bioretention cells near the Troll at the Aurora Bridge are an inspiring example of a project whose beauty and functionality are evenly balanced, and whose impact is equal This design project is ultimately a visioning parts anthropocentric and ecological. exercise in how we can re-conceptualize Although my project will never get made, urban waterways and shorelines without I hope that it encourages us all to imagine having to tear the whole thing down and richer, more alive shorelines in the city. start over. into human constraints of what qualifies as a “site” or not. While the ecological function of the Ship Canal will likely never be fully restored, it is important to consider the restoration options that are available to us. We tend to view the urban built environment as static, but that’s not always the case - can we find the areas of flexion, and push them to their limits? This project attempted to do just that, and provide some answers to questions that have yet to be asked.
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