Understanding Habitat

9 10 2012

An introduction to in-water, seawall habitat

Habitat restoration along Seattle’s seawall

To make life better for juvenile salmonids and other marine creatures, the City is designing a shallow, lighted migratory corridor along the seawall to enhance habitat for juvenile salmon and other marine life.  The City is planning to restore habitat by:

Elliott Bay Seawall:  An important salmon migration corridor

Tens of thousands of salmon migrate along the Elliott Bay Seawall and then up the Green/Duwamish River and its tributaries every year to spawn.  After beginning their lives in freshwater rivers, juvenile salmon then swim down the Green/Duwamish River to enter Elliott Bay in the spring and summer – along the Elliott Bay Seawall. Because the Elliott Bay Seawall Project area is such an important link in the salmon migratory route, improving salmon habitat within Elliott Bay is pivotal to the success of regional salmon recovery.

Historically, the eastern shoreline of Elliott Bay looked much like other unaltered shorelines across Puget Sound—a bluff-backed beach with intertidal marshes and mudflats.  The mudflats and gently sloping beaches of Elliott Bay were home to a bounty of birds, fish, and marine invertebrates.

When the seawall was built, the nearshore was cleared to make room for piers, roads, and buildings. With the lack of typical nearshore habitat, salmon migrating along the waterfront can become confused and vulnerable to predators.  Current challenges that juvenile salmon encounter along the seawall include:

  • Large piers, which cast shadows on the water, limiting the ability of aquatic vegetation to grow and making it difficult for juvenile salmon to navigate along the seawall.
  • Vertical hard surfacesmake it difficult for marine invertebrates, an important food source for salmon, to colonize the seawall.
  • The seawall currently lacks an intertidal zone.  In intertidal zones, land is above water at low tide and below water at high tide.  Intertidal zones provide outstanding sources of food and shelter for juvenile salmon.
  • The seawall lacks bluffs with riparian vegetation, a typically important source of habitat structure, refuge, and food for salmon.

Despite these challenging aspects, today’s seawall still provides a home to many species of aquatic life.

  • The naturally lighted areas between piers along the central waterfront are home to many types of aquatic vegetation, such as sea lettuce, and marine invertebrates like barnacles, mussels, and sponges.
  • Biologists have identified eight species of salmon, and many other species of fish, that use seawall habitats

Researching how to improve habitat

As part of the seawall replacement program, the City of Seattle is committed to restoring a functional salmon migration corridor along Seattle’s waterfront.  The Elliott Bay Seawall Project has been researching how best aquatic habitat can be restored.

Since 2008, four major studies have been conducted along Seattle’s waterfront:

  • Habitat monitoring at Olympic Sculpture Park – Researchers are monitoring how marine life is responding to habitat restoration along the park’s shoreline.
  • Exploring habitat-friendly surfaces – Researchers are monitoring test panels with new possible surfaces for the seawall to understand which surfaces are best for marine life.
  • Habitat mapping – Through underwater video and SCUBA dives, biologists are mapping what plants and animals can currently be found along the seawall.
  • Examining juvenile salmon migration patterns – To understand how habitat restoration along the new seawall could help juvenile salmon migration, researchers are studying current migration patterns to learn how juveniles migrate and how limited habitat along the seawall currently affects their migration patterns.

Waterfront Seattle’s latest Transportation Design Plans

20 09 2012
“The needs of each mode of transportation will be balanced to create a great urban place and experience for all to enjoy.”

Check out Waterfront Seattle’s latest transportation design plans here: http://waterfrontseattle.org/downloads/Waterfront_Seattle_Design_Summary_July2012.pdf

Lisbon, An Inspiration

15 06 2012

A plaza in Lisbon’s Baixa neighborhood. More Photos »

Lisbon, a waterfront city in Portugal, is reminisced about in this travel writer’s article in the NY Times. What fond memories do you have of inspirational waterfronts?


Conservation Magazine Article: How to Build a Living Seawall

20 03 2012

How to Build a Living Seawall

Simple fixes bring marine life back to urban coastlines


In the coming decades, coastal communities will build or reinforce hundreds of miles of seawalls, breakwaters, and other coastal defenses to protect themselves against rising sea levels and increased storms, as well as to accommodate growing populations.

Already, more than half the shoreline in parts of Japan, Europe, the U.S., and Australia is artificial. And that puts the squeeze on intertidal creatures. Seawalls and similar structures truncate the gradual slope of natural intertidal zones and sharply reduce the area available for species that depend on this habitat.

But lately, researchers are making the case that these structures can be compatible with a healthy measure of marine life—and at very little extra expense, says Mark Browne, a marine ecologist at University College Dublin.

Several years ago, Browne—then a postdoctoral fellow at the University of Sydney in Australia—was part of a team of ecologists who bolted ten-liter flowerpots made of cast concrete to the seawall in Sydney Harbour. The vessels retained water at low tide, mimicking the tide pools found on natural rocky shores.

Seven months later, the researchers counted 25 species in the pots that weren’t present on adjacent sections of the vertical seawall, an increase in species richness of 64 percent.1 “We were getting universal increases across the different phyla that we were looking at,” says Browne—large crabs, sea stars, sponges, tube worms, snails that thrive in sheltered habitat, a diversity of seaweeds. A previous experiment in Sydney Harbour was even cheaper. Engineers simply left out a few of the sandstone blocks from a new seawall. This created cavities that soon became home to urchins, sea slugs—even octopus.

“Even quite small modifications to the seawall surface will increase the diversity” of species, adds Richard Thompson, professor of marine science and engineering at Plymouth University in the U.K. Thompson was part of a team that drilled small holes—about the diameter and depth of a coin—into concrete panels and then attached them to a nearby seawall. Where only one or two species of intertidal organisms typically colonized a section of standard seawall, up to 16 might be present on the textured surface, the researchers found. The experimental panels “were a poor comparison” to natural rocky shoreline, Thompson cautions, “but they were far better than the smooth concrete.”

Those results call for a shift in thinking on the part of engineers and designers, who tend to default to smooth, rectilinear structures. “As human beings we want things that are sleek and straight and orthogonal, and that does not help ecology,” says Cristina Bump, a Boston-based architect who has studied efforts to enhance seawall habitat in both Sydney, Australia, and Seattle, Washington—where a multimillion-dollar, twenty-block seawall reconstruction project is getting underway.

For the Seattle study, a team from the University of Washington bolted a number of five-feet-by-seven-and-a-half-feet concrete panels to the seawall. Some of the panels had “steps” or “fins” projecting a foot or two off the vertical surface. Some had an all-over bumpy texture, achieved by casting the concrete in a mold used to make faux-cobblestone patios. “We just used something that was already out there,” says Maureen Goff, who worked on the project as a master’s student. “We looked at trying to place real rocks into concrete, but it was structurally not great, and more expensive.” There’s a learning curve for ecologists in this field, too.

The researchers installed the panels at three sites along Seattle’s downtown waterfront and monitored the marine life that colonized the surfaces over a period of two years. “The overall community was pretty similar to a vertical seawall, but we discovered that certain features are good for certain organisms,” says research ecologist Jason Toft. Mussels found purchase in the spaces between the “cobbles.” Exuberant stands of Fucus, a greenish-brown seaweed that provides habitat for other intertidal species, grew on the horizontal surfaces. Copepods and fly larvae called chironomids congregated above and below the fins and steps, perhaps finding that these spots were sheltered from the waves.

Similar features and textures may be incorporated into the rebuild of Seattle’s seawall. The city would especially like to have more copepods and chironomids around, because these animals provide food for young endangered salmon.

“There’s a lot that lives down there,” Toft says. Even in a highly urbanized stretch of waterfront, a surprising number of species can thrive with just a few, relatively inexpensive tweaks to their habitat. A cobble, a divot, a cranny—sometimes, what nature needs from us
is just a little bump. ❧

—Sarah DeWeerdt, Conservation Magazine

1. Browne, M. and M. Chapman. 2011. Environmental Science & Technology doi:10.1021/es201924b.

Graphic courtesy of Cristina Bump, Associate AIA, LEED AP  www.cristinabump.carbonmade.com

Upcoming Seattle Waterfront Events

19 01 2012

The waterfront is a treasure that belongs to all of us.
Join us for a series of informal discussions on some key topics that are shaping the future of the waterfront. Now is the time to get involved!

5:30 – 7:00 pm
Downstairs at Town Hall Seattle
1119 8th Avenue, Seattle
Events are free. Space is limited.
RSVP: rsvp@waterfrontseattle.org

Tuesday, January 31: Climate and Context
How can we make the waterfront an attractive place for all seasons?

Wednesday, February 8: Mobility and Access
The waterfront is a crossroads. How do we balance the many transporation needs?

Wednesday, February 15: Uniquely Seattle
Seattle’s waterfront has a rich context and history. How can we design it to reflect the uniqueness of the place and speak to our past, present and future?            

Monday, February 27: Environment and Ecology
How can the waterfront help to restore the natural
ecology of Elliott Bay and showcase sustainable design?

Monday, March 5: Setting the Stage
How do we create vibrant spaces  for arts, culture
and entertainment?

Questions or comments?

Check out Milepost 31

10 01 2012

Milepost 31 highlights the people and projects that shaped Pioneer Square and provides an inside look at the SR 99 Tunnel Project.

What’s inside?

Inside Milepost 31
View more photos on Flickr.

Visitors to Milepost 31 will find more than just construction photos and brochures. You’ll find history, artifacts and interactive exhibits designed to broaden your understanding of the land beneath you. You’ll explore the neighborhood’s changing landscape, from earth-moving efforts of the past to the massive tunnel project that will soon move State Route 99 underground and reconnect Pioneer Square to the waterfront.

Visitors can browse through four sections:

  • You are here: Similar to the “you are here” points on maps, this section orients visitors to Milepost 31. It tells the story of the land upon which you are standing from the perspective of several different historical figures.
  • Moving Land: This section examines how the natural forces of glaciers, earthquakes and volcanoes have transformed Seattle’s landscape during the past 15,000 years. Visitors will also learn about our own effects on the land, from the filling of the tidelands in Pioneer Square to the various regrade projects across the city.
  • Moving People: This section tracks transportation over time, with an emphasis on Pioneer Square. Visitors will see how people-moving has changed – and in some cases stayed the same.
  • Moving Forward: This section is all about tunneling. Visitors will learn about the history of tunneling technology, tunneling in Seattle and, of course, the SR 99 Tunnel Project. In addition, exhibits show visitors how the project – along with the Elliott Bay Seawall Replacement and Waterfront Seattle – will transform the future of Pioneer Square.
Map showing Milepost 31 in Pioneer Square Where to find us
Milepost 31 is located at 211 First Ave. S. (between South Washington and South Main streets) in Seattle.

Why create Milepost 31?

This information center is required by a memorandum of agreement (pdf 510 kb) signed as part of the Alaskan Way Viaduct Replacement Project. The agreement was developed to address Section 106 of the National Historic Preservation Act, which requires agencies to take into account the effects of their projects on historic properties, such as those in the Pioneer Square Historic District.

Within the agreement, city and state preservation officers along with the Federal Highway Administration, national and local preservation groups, neighborhood organizations and local tribes determined that a project information center is one way WSDOT could help to keep Pioneer Square vital during construction. The agreement also calls for WSDOT to monitor and protect historic buildings during SR 99 tunnel construction and to develop traffic management and construction coordination plans for Pioneer Square.

Why the name “Milepost 31”?

Mileposts mark progress. They help you track where you are on your journey, reminding you of the places you’ve passed through on your way to somewhere else.

But what if a milepost is so interesting that it becomes a destination? Located on SR 99 at the western edge of Pioneer Square, Milepost 31 is that kind of place. It marks a spot on the highway, but it also marks the spot where, before mileposts existed, mile-thick glaciers gave way to native civilizations. It’s where Seattle’s first neighborhood saw the rise of the city’s most notorious stretch of highway – the SR 99 Alaskan Way Viaduct – and where crews building the world’s largest diameter bored tunnel to replace the viaduct will first cross into the soils beneath Pioneer Square.

211 First Ave. S., Seattle (between South Washington and South Main streets)
Admission is free. Tues-Sat 11am-5pm

James Corner’s waterfront plans: get the editing pencil

9 11 2011

The success of some New York public spaces such as the High Line and Bryant Park may be leading the architect for Seattle’s proposed Waterfront Park to crowd and over-program a space that cries out for serenity and introspection.