Across the Pacific Northwest, urban sprawl is decimating salmon habitat.

Fish scientists who study the effects of urbanization on salmon, steelhead and orcas are unanimous: To save these iconic and vital species we must prevent sprawling development from ruining the sensitive watersheds they depend on.

And this realization leads to an inescapable conclusion: Limiting further sprawl means we must provide more homes for more people in already-developed parts of our metro regions.

In addition to giving more families the option to live closer to jobs and daily needs, such infill of human habitat is a great deal for salmon habitat. Every apartment building, rowhouse, or cottage built in an already-developed area prevents the disruption of far more expansive swaths of habitat  on the metro fringe.

That disruption is severe, not only because watersheds are paved and mangled, but also because the resulting long car commutes mean more and bigger roads, and more pollutants washing from them into streams—to say nothing of the climate-harming carbon emissions. 

Sure, Paris-style densities in close-in areas might make things a little worse for some of those watersheds, but there, most of the damage has already been done. More homes on less land helps keep much larger and more ecologically functional areas intact to support salmon recovery. 

Today, however, most local governments have outlawed anything but one-house-per-lot in the lion’s share of their jurisdictions. Undoing those bans is a critical piece of salmon recovery. On top of that, ubiquitous city mandates for new homes to include parking spaces exacerbate habitat destruction not only by reinforcing car dependence, but also by making housing construction more expensive.

Local laws that lock in lawn-and-driveway housing are deeply entrenched in local politics. State governments in Cascadia have already enacted a wide array of environmental laws to protect salmon, yet the decimation persists. To boost their efforts, state lawmakers can set statewide, uniform standards for cities to allow more homes in places already urbanized, so that more of the state’s watersheds will survive to support salmon.

The sorry State of Salmon 

In Washington, 17 populations of salmon and steelhead are threatened or endangered under the federal Endangered Species Act. In response, the state 20 years ago began planning and investing for “salmon recovery,” but populations continue to decline. As one example, over the past decade in the Puget Sound’s urbanized watershed, some 90 percent of coho salmon died before they could spawn according to the most recent State of Salmon report from the Governor’s Salmon Recovery Office.

“Population growth in Washington State is projected to continue to increase,” according to the report, “leading to further urban development. By 2037, Washington’s population is projected to surpass 9 million people, most of whom will move [here]. The byproducts of this growth—urban expansion, shoreline armoring, and toxic stormwater runoff—harm salmon and damage their habitat.”

The degree of acceptable human impact to habitat is frightfully low. Paving over just 15 percent of a watershed causes coho to all but disappear—a fact that has been known for more than 20 years. (See page 26 of 1996’s The Car and the City.) And while the state has adopted environmental and planning rules in response, the local zoning that could bolster them remain virtually untouched.

From Acts… to action

In principle, cities and counties in Washington have been planning for growth with salmon and other vital ecological considerations in mind since at least the 1990s under the state’s Growth Management Act (GMA). They have been managing near-water areas even longer, since 1971’s Shoreline Management Act (SMA). In 2009, the state Department of Fish and Wildlife put out a guide to land use planning for salmon

“The acts are good tools for planning, but they are not as effective as they could be,” said Hugo Flores, environmental planner in the aquatic resources division of the state Department of Natural Resources. 

Indeed, a two-years-in-the-making assessment of the Growth Management Act released in 2019 concluded that, “despite the expenditure of millions of dollars and decades of efforts by local, state, and regional agencies, and tribal governments,” those efforts are not succeeding. 

Although the GMA and SMA both require local governments to identify “critical areas” for ecological function, Flores said, “We have to start to assess and disclose the real impact that developing the land will have on streams and salmon recovery.” 

Some in the Legislature are starting to hear that message, not just from environmental planners, but from the Northwest tribes whose cultural and economic vitality depend on salmon recovery, who have urged the state to change the GMA’s goal of “no net loss” of salmon-critical areas to “net gain.” In response, Sen. Jesse Salomon (D-Shoreline) and seven co-sponsors recently introduced Senate Bill 6454, which seeks to strengthen the requirements to plan for preserving salmon habitat under the GMA. In the House, Rep. Debra Lekanoff (D-Skagit Valley) and co-sponsors have introduced HB 2549, which would add salmon recovery as an express goal of the GMA and mandate cities and counties to adopt and implement regulations and policies to protect or improve salmon habitat.

Breaching the dam of local land-use practices

These state efforts on habitat protection areas are completely necessary, but fundamentally insufficient. Today, the decisions about what gets built and where are almost completely the domain of local governments—and most are deciding to restrict home-building in ways that all but assure the continuation of sprawl and the failure of well-intended planning laws.

Merely putting land off-limits to human habitat—development, in other words—will not work if we aren’t at the same time identifying where we do want people to live. Restricting the expansion of development inevitably requires loosening laws to allow the housing people need within existing developed areas. 

Local jurisdictions that guide and regulate development are subject to often extreme political pressure to minimize construction of additional housing within existing neighborhoods. “Single family zones” that ban everything but detached houses on big lots are particularly held as sacrosanct and in most cities occupy three quarters or more of land available for residences.

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  • Some states are beginning to see the need for statewide action on land use—even if the link to salmon survival isn’t a key driver. Last summer, Oregon lawmakers legalized duplexes almost everywhere, and up to fourplexes in larger cities. In California, Senate Bill 50 to upzone for housing near transit throughout the state missed adoption by three Senate votes in January, but other dense-housing bills are under consideration. In Washington this legislative session, several proposed measures would require local governments to allow more housing in cities, with a primary goal of creating more homes near jobs in hopes of improving affordability. But by helping to limit the human footprint, such moves could help salmon, too, experts say.

    How the human footprint stomps on salmon 

    “With more people, more spread out, you have more cars,” said Daniel Schindler, an ecologist in the School of Aquatic and Fishery Sciences at the University of Washington. Those cars “come with pollutants from oil and gas leaks, road dust from brake pads and other pollutants that have been shown to be toxic to fish. Reducing the amount of cars on the road, protecting riparian areas and restoring them where degraded would be the most helpful strategies for salmon.”

    Pavement is one of the real killers, said George Pess, program manager at NOAA’s Northwest Fisheries Science Center in Seattle. “When you develop and pave over a place rainwater hits the ground and goes right into the stream, rather than seeping through the soil and being part of the groundwater.” The “flash flooding” from urban stormwater runoff can scour the stream bed and disrupt [salmon spawning]  nests.” It also eliminates the calm areas where newborn fish feed, he added. 

    Some will argue that suburban densities and single-detached houses on large lots have less impervious surface and therefore have lower watershed impacts than higher density. While that is true to an extent, there are two problems with that assumption. First, as discussed above, at the regional scale, what is most critical is limiting the overall human footprint. And second, it turns out that suburban densities aren’t terribly helpful to watershed preservation. 

    Craig Orr was for many years the executive director of the Watershed Watch Salmon Society in British Columbia, and today serves as conservation advisor to Watershed Watch as well as the Kwikwetlem First Nation. The problem in suburban areas of lower density, he noted, is that there is still plenty of pavement for roads, driveways and parking lots because people have to drive for everything. Beyond that, he said, “We tend to withdraw water for green yards and gardens and that can reduce in-stream flow… even to wash cars,” he said. 

    In addition, compacted lawns with thick mats of grass can be little better than concrete in slowing runoff, and that runoff is often contaminated with lawn chemicals. With increasing water restrictions, he said, “We have a growing issue of people putting in Astroturf, which sends plastic bits into the marine ecosystem.” He supports efforts in his home city of Coquitlam—a suburb connected to Vancouver via SkyTrain—to focus new housing and commerce around transit hubs to “reduce the overall footprint.” 

    But both he and NOAA’s Pess note that, to supplement the regional watershed benefits, infill housing can be developed in ways that minimize damage to salmon-supporting watersheds locally. The first rule is to avoid especially sensitive areas. “If you have high-density right along a creek, in a sensitive area, it is going to have an impact. Are you adding density in a floodplain area, or in one that is a terrace with well-drained soils? You have to look at the features of the landscape.” Washington and Oregon already have numerous environmental laws restricting development in sensitive locations.  

    Green stormwater infrastructure (GSI) has to go hand in hand with denser development,” and should be the norm wherever development occurs. GSI, as the US EPA describes is it, uses “plant or soil systems, permeable surfaces … or substrates, or landscaping” to store and filter stormwater rather than pipe it directly to streams, or to capture it for reuse. Requirements for GSI are increasingly the norm in city codes. In another effort to make infill help rather than harm, the organization Salmon-Safe has created a certification program for large urban projects

    Making it safe to build human habitat

    But to return to where we started, all the GMA-driven plans in the world will do little more than occupy shelf space—and will do less for salmon—if we can’t figure out how to make more efficient use of already-developed land. People are coming and they need to live somewhere. More than two decades of growth management and recovery planning have sputtered in large measure because we essentially leave it up to local jurisdictions to decide whether we sprawl or not. 

    At the local level, legalizing more housing in areas zoned “single-family” within the watersheds already disturbed by human activity faces a steep political climb. State environmental laws to protect salmon have proven insufficient. State standards for infill housing and parking can overcome the local logjam and empower much-needed statewide progress on preserving the watersheds that salmon depend on, while also helping more families find homes they can afford.

    For the sake of both humans and fish, such reform is critical, experts said. “Really, at the end of the day for salmon, we have to be humble,” said NOAA’s Pess. “There’s a lot we don’t understand. But when we know places that are working for them and something about why they work, staying away from them is the best thing we can do.”