Environmental Engineering Reference
In-Depth Information
• Restore ecosystem processes, structures, and functions that sustain Puget Sound
• Prevent water pollution at its source
These strategies guide landscape-scale and local project selection and funding, and
focus on protecting the large remaining riparian, estuarine, and nearshore areas; re-
ducing water pollution sources, such as stormwater; and reducing shoreline armoring
and impervious surfaces.
Population growth, increasing urbanization, and transportation behaviors exacer-
bate these challenges. Indeed, this restoration effort takes place in the socioeconomic
context of the Seattle metropolitan area, the largest urban area in the Pacific North-
west with a dense human population and high economic activity. The Puget Sound
region has roughly four million residents as of 2010 and is expected to grow to five mil-
lion by 2030 (Washington State Office of Financial Management 2007). Including
the Canadian portions of the overall Puget Sound-Georgia Basin increases these pop-
ulation numbers by more than 40 percent (U.S. EPA 2010). Given the situation, the
PSP recognizes the impracticality of restoring the region to some historical condition,
and instead focuses on restoring natural capital and ecosystem processes to resilient
levels.
Further complicating the challenge are the ongoing and anticipated effects of cli-
mate change on the region. Already, average annual temperature has increased, with
the greatest increases during the winter months, snow water equivalent as of April 1
has declined, and peak runoff is earlier (Mote et al. 2003; Stewart, Cayan, and Det-
tinger 2005). The Climate Impacts Group at the University of Washington projects
that temperatures in the Pacific Northwest will increase across all seasons, with sum-
mer (June-August) temperatures increasing the most. They also foresee relatively
constant total annual precipitation, although more of the precipitation will be con-
centrated during the winter, with decreasing summer precipitation (Elsner et al.
2010). Much of this is due to a projection that calls for less overall snowfall and faster
snowmelt. The Washington Climate Change Impacts Assessment concluded that
these temperature and precipitation patterns would substantially decrease the quality
and quantity of salmon habitat and increase the area burned by wildfire by 100 to 250
percent (Miles et al. 2010).
Sea-level rise has numerous driving global and local factors, and the estimates for
Puget Sound are for a 21.7-inch (55-cm) increase by 2050 and a 50.4-inch (128 cm)
increase by 2100 (Lettenmaier and Milly 2009; Mote et al. 2008). With the focus on
protecting and restoring estuaries and nearshore environments, as well as de-armoring
shorelines, sea-level rise reduces the expected lifespan and overall benefit of restora-
tion projects in the nearshore/estuarine zone and increases the uncertainty of target-
ing appropriate locations for restoration projects designed to provide critical habitat to
juvenile salmonids. Acquiring and restoring property in floodplains and the nearshore
region might not be targeting areas most appropriate for those systems a hundred years
from now. It can also become more costly, as the focus must shift from areas intermit-
tently flooded and with relatively little development to higher elevation, more valu-
able, and more developed areas. While the PSP identifies stormwater runoff as the
