Ecosystem services enhanced by salmon habitat conservation in the Green/Duwamish and Central Puget Sound watershed


caption Figure 1. Map of WRIA 9 and Subwatersheds. (Source: Earth Economics)

Restoring salmon has significant socio-economic implications. The greatest socio-economic implication of salmon recovery is securing healthy ecosystems, which provide vast public and private benefits. Healthy ecosystems produce goods and services for free and in perpetuity.

Ecosystems are the most economically efficient production systems for many critical goods and services. For example, healthy riparian areas filter drinking water, move a vast amount of storm water, channel flood waters, recharge aquifers and replenish surface waters. Replacing these services with engineering solutions requires costly capital projects-- such as levees, storm water systems, and water filtration facilities-- and maintenance costs.

The Water Resource Inventory Area 9 (WRIA 9) Habitat Plan is a long-term, comprehensive plan to protect and restore Chinook salmon in the Green/Duwamish and Central Puget Sound Watershed. Wild salmon are more than an indicator species. Salmon are a valuable economic asset in and of themselves. The WRIA 9 Habitat Plan actions to restore viable salmonid populations will also preserve and restore 23 categories of valuable ecosystem goods and services identified in the Green/Duwamish and Central Puget Sound Watershed. Ecosystem goods and services enhanced by Habitat Plan actions include: flood protection, natural storm water maintenance, drinking water production and filtration, reduction of pathogens and pollutants, waste absorption, storm protection, biodiversity preservation, nutrient regulation, increased production of fish, shellfish and other food and raw materials, erosion control, biodiversity, aesthetic value, recreational fishing, hunting, hiking, bird watching and educational and scientific benefits.

Until recently, the natural capital, goods and services produced by ecosystems within WRIA 9, including wild salmon, have been abundant. At one time, only a shortage of boats and nets limited the amount of abundant wild salmon caught. Today boats, nets and fishing lures are abundant and a shortage of natural capital—wild salmon—is the limiting factor.

Healthy ecosystems, healthy economies and healthy communities are all necessary to maintain and raise the high quality of life that citizens within WRIA 9 enjoy. As ecosystems are degraded, quality of life suffers, and citizens pay significant socio-economic costs. Either property owners suffer greater losses from increased flooding and other damage, or cities and counties must replace previously free ecosystem services with increasingly expensive engineering solutions. Increased expenses from lost ecosystem services include increased water filtration costs, storm water management, flood control, endangered species restoration, land slide damage, increased crime and other problems resulting from a degraded environment. The full value of the benefits provided by ecosystems within WRIA 9 has never previously been estimated.

Project Methods

The WRIA 9 conservation hypotheses identify the habitat conditions that are important or critical for salmon recovery based on best available science. Salmon restoration actions, then, not only restore salmon but also provide a basket of other valuable ecological services.

The Seattle based Asia-Pacific Environmental Exchange (APEX), with the University of Vermont Gund Institute for Ecological Economics, worked with the WRIA 9 staff to estimate the value of ecosystem goods and services produced within the Green/Duwamish and Central Puget Sound Watershed. The ecosystem goods and services enhanced by salmon recovery actions (undertaken to implement the Habitat Plan Conservation Hypotheses) were identified. Two case studies for salmon restoration actions in the transition zone of the Green River and in the nearshore were also examined using ecological economics analysis for their value added contribution to ecosystem services.

To understand the value of goods and services provided by ecosystems within WRIA 9, geographic information system (GIS) data for WRIA 9 was compiled for the acreages of forest, grass and shrublands, agriculture and pasturelands, wetlands, urban areas, lakes, ponds, rivers and streams, ice and rock. The team selected peer reviewed journal articles for each land use type and the value of associated ecological services. A benefit transfer methodology was applied to WRIA 9 to calculate a range of dollar value of ecosystem services provided annually within WRIA 9.

Project Results

Valuation Scenarios

Ecosystems within WRIA 9 provide a dollar value greater than the range of $1.7-6.3 billion in ecosystem services annually. This is an underestimate of the true value because not all ecological services were valued. For example, because studies estimating many ecosystem services readily identified as valuable in the nearshore have not been conducted, the estimate for the value nearshore and coastal ecosystem services is far below the actual value.

Using the Army Corps of Engineers discount rate of 3.5 percent (over the next 100 years) this flow of annual benefits by ecosystems within WRIA 9 totals to $48.5-180.7 billion in net present value. Salmon are more than an indicator species for this tremendous amount of value. Secure native salmon populations ensure that much of the critical habitat producing these ecosystem services is also secured.

Notably, there is also reason to consider the value of ecological services without discounting. Healthy ecosystems do not depreciate or require maintenance costs. Once restored, ecosystems are self-maintaining and appreciate in value. In contrast, human-built capital, such as a car, requires maintenance and depreciates over time. After providing valuable service a car becomes garbage or recycling. Our grandchildren will likely get little use from the cars we now drive. However, they will unquestionably benefit from the drinking water, flood protection, Chinook salmon and recreation provided by healthy ecosystems. For these reasons it is important to be aware of the socio-economic value of ecosystem services without discounting future value.

Applying a zero discount rate (giving equal value to the service benefits of future generations) to the flow of WRIA 9 ecosystem service benefits across the next 100 years yields a net present value of $171-637 billion over 100 years. Considering that these ecosystems have been productive for thousands of years, and if restored to health could produce these benefits into the indefinite future, this $171-637 billion represents only a small slice of the potential benefits healthy WRIA 9 ecosystems can produce for future generations. By enhancing salmon habitat, WRIA 9 ecosystems are enhanced and the public benefits both directly and financially.

Another marker of value, the total value of taxed property within WRIA 9, was calculated at $71 billion. Of this, $44 billion consists of improvements on property, which clearly represents built human capital and has taken 150 years to accumulate. Over $23 billion of taxed property value is in land value, representing social, speculative, aesthetic and ecological values.

North Winds Weir Analysis

The North Winds Weir Project expands salmon habitat in the transition zone from fresh to salt water. Transition zone habitat is essential to salmon and may be so scarce that salmon extinction could result without increased transition habitat. This meets the criteria of “critical natural habitat.” Though economic methods are based on marginal analyses and not well suited as a threshold for extinction, four different approaches to valuing the expansion of transition zone habitat justify high levels of expenditure actions to reclaim transition zone habitat.

Expenditures for salmon restoration within WRIA 9 to date exceed $59 million and are expected to rise. Total expenditures over the next 10 years are likely to be $292-706 million or greater. This investment could be lost without securing sufficient transition zone habitat.

Scientific analysis shows that continued salmonid declines are likely without additional transition zone habitat. As a result, if increased transition zone habitat is not acquired now, the Federal Government may require the acquisition of transitional zone habitat at a future date. If salmonid populations are further depressed, a larger acquisition of transition zone habitat may be required to restore populations.

Ecosystem services would also be enhanced with increased transition zone habitat for salmon. An underestimate, valuing a subset of ecosystem service values produced by the North Winds Weir provides a net present value for the project up to $1.4 million. Using a zero discount rate provides values of $1.35-23.72 million in net value for the North Wind’s Weir depending on the time horizon considered. This partial analysis does not account for the value of securing viable salmonid species.

Finally, considering the full suite of expenditures for salmon recovery and the critical habitat functions provided by the transition zone, expenditures on the order of $19 million—far higher than the cost of the North Winds Weir—would be justified.

Ecosystem Services and Removal of Armoring in the Nearshore

The near shore is important habitat for salmonids, particularly young Chinook salmon. The restoration of nearshore habitat also contributes to greater ecosystem service production. Though ecosystem service values in the nearshore of WRIA 9 are high, many nearshore ecosystem services have simply never been valued leaving many gaps in the literature. Peer-reviewed valuation studies representing 25 ecosystem services associated with particular land forms and habitats in the nearshore have been conducted. However, there are 161 other identified ecosystem service/habitat/landform associations for which no valuation studies exist. The value of ecosystem services produced in the nearshore is high, thus any benefit transfer valuation of nearshore ecosystem services is necessarily significantly below the true value. With this consideration, APEX identified ecosystem services most likely to be enhanced by removal of coastal armoring as were the ecosystem services associated with two conservation hypotheses associated with removal of armoring.

Another critical factor in this analysis is the lack of understanding of the dynamic oceanographic and biological processes that relate structure, function, process and value in the nearshore. WRIA 9 conservation hypotheses in the nearshore, as throughout WRIA 9, support the strengthening of healthy ecosystems and corresponding rises in the value of increased ecosystem goods and services. A partial estimate of the total value of ecosystem services provided by submerged aquatic vegetation (SAV) alone shows that armoring, docks and launches have contributed to the loss of over $45 million annually in Puget Sound. WRIA 9 is the most heavily armored and affected area along the Sound and accounts for a large portion of those losses. Removal of armoring also supports two salmon conservation hypotheses that would increase the quantity and value of ecological services provided. Depending on the site, oceanographic affects on siltation, SAV, and other dynamics, these salmon restoration actions in the nearshore likely would have a high value.


Ecosystem goods and services are essential to maintaining a healthy economy and livable communities within WRIA 9. The standard of living in WRIA 9 is a product of the natural, social and human-built capital. It is crucial to recognize the essential contribution of natural and social capital to wellbeing. To understand the value of ecosystems to the public and economy, it is critical to understand how ecosystems function and how salmon restoration enhances their value to people. WRIA 9 ecosystems produce $1.7-6.3 billion dollars of value in goods and services each year, benefiting individuals, communities, businesses, and governments within WRIA 9. The value of salmon restoration and healthy ecosystems to future generations is far greater.

Further Reading



Economics, E. (2007). Ecosystem services enhanced by salmon habitat conservation in the Green/Duwamish and Central Puget Sound watershed. Retrieved from


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