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Development Prototype: Puget Sound Ecosystem Portfolio Model

Resource Impacts

Two models – the Shellfish Pollution Model and the Beach Armoring Index – describe changes to beach condition: beach water quality and beach geomorphology and habitat. Results from these models and the Recreation Visits model influence potential changes to nearshore resources, including ecosystem goods and services and valued ecosystem components. The maps in the Resource Impacts page represent intersections of model results and existing data to illustrate potential effects on nearshore resources across three scenarios out to 2060. Through these modeling efforts with the best available science, we are connecting the effect of land use policy decisions on the nearshore ecosystem.

We explore potential changes to three resources:

Forage fish spawning habitat

Recreational shellfish beaches

Recreational beach quality

Forage Fish Spawning Habitat
  An intersection of beach armoring index scores at forage fish spawning beaches

Forage fish, including surf smelt (Hypomesus pretiosus), Pacific sand lance (Ammodytes hexapterus), and Pacific herring (Clupea pallasi) are critical prey species for economically important predators such as salmon. These fish and their spawning habitats occur within the nearshore zone of Puget Sound beaches. Surf smelt and Pacific sand lance require a suitable amount of sand-gravel mix substrate at a tidal elevation in the uppermost one third of a shoreline’s tidal range (Penttila 2007). Shoreline armoring may be the primary threat to surf smelt and sand lance spawning habitat (Thom et al. 1994), as armoring results in physical burial of the upper intertidal zone and reduced sediment supply to beaches (Johannessen and MacLennan 2007).

In October 2009, the Washington Department of Fish and Wildlife provided surf smelt and Pacific sand lance spawning occurrence data attributed to the Washington Department of Natural Resources ShoreZone GIS data. Over the last 30 years, over 30,000 samples were collected and mapped onto ShoreZone beaches. In the dataset, the number of surveys represents the number of times egg surveys occurred at a given beach. A beach is designated a spawning beach if more than one egg is identified in one or more surveys. The WDFW Priority Habitats/Species Program forage fish databases are considered “best available science” and jurisdictions are urged to adopt and reference them in Growth Management Act mandated regulatory language (Penttila, D. 2007).

The Forage Fish Resource Impacts maps display the WDFW surf smelt and Pacific sand land spawning beaches overlaid with the Beach Armoring Index. Icons for spawning beaches are color-coded to represent index scores. While multiple human stressors can threaten spawning beaches, including loss of marine riparian vegetation, overwater structures, and dredging (Penttila 2007), this map focuses on threats from armoring, primarily loss of beach sediment supply. As described in the Beach Armoring Index description , The ENVISION Managed Growth scenario assumed no future shoreline armoring; as a result there is no change in index scores for this scenario across decades. Also, the ENVISION model projected low armoring rates in the Status Quo and Unconstrained Growth scenarios out to 2060, as a result there are few changes in index scores for these beaches over time.

Overall, most forage fish spawning beaches had moderate to low beach armoring index scores (0.5 – 3). Only 159 beaches out of 1091 had scores of 3.25 – 5 for the year 2000 baseline dataset. Most of these beaches were in the South Puget Sound subbasin (73 beaches) (Figure 1) followed by the South Central subbasin (54 beaches). As the ENVISION model projected minimal increases in beach armoring by 2060 for both the Unconstrained Growth and Status Quo scenarios, few forage fish spawning beaches experience changes in Index scores in the scenario analysis. Under the Unconstrained Growth Scenario, the South Central Subbasin would experience the greatest increase in Beach Armoring Index scores by 2060 with 11 beaches changing, followed by the South Puget subbasin, with 8 beaches changing. (Figure 2).

Figure 1. Beach armoring index scores at forage fish spawning beaches by Puget Sound subbasin: year 2000 baseline data

Beach armoring index scores chart

Figure 2. Change in Beach Armoring Index Score at Forage Fish Spawning Beaches from 2000 – 2060 under the Unconstrained Growth Scenario

Beach armoring index scores chart

 

Recreational Shellfish Beaches
  Recreational shellfish harvests and surrounding water quality

The Washington Department of Health Office of Shellfish and Water Protection classify recreational shellfish beaches as Approved, Conditionally Approved, Restricted, or Prohibited based on the same National Shellfish Sanitation Program standards used for commercial shellfish growing areas. For an approved classification, the beach must meet the two-part standard of:

  1. The concentration of fecal coliform bacteria (indicator organism) cannot exceed a geometric mean of 14 per 100 ml and

  2. The estimated 90th percentile cannot exceed 43 organisms per 100 ml in areas potentially impacted by nonpoint source pollution. If sampling where point sources of pollution may impact the growing area, not more than 10 percent of the samples can exceed 43 organisms per 100 ml. Even if these criteria are met, an area may be classified as conditionally approved, restricted, or prohibited if pollution sources could impact sanitary conditions of the shellfish (OSWP 2010).

Water quality stations were established at numerous recreational beaches in recent years, which enabled DOH to classify 288 beaches in Washington State in 2009. Over half of these beaches were classified as approved http://www.doh.wa.gov/ehp/sf/Pubs/ai-map.pdf. There are about 160 additional recreational shellfish beaches in Washington that have not yet been classified due to lack of water quality data.

In this map recreational beaches are classified based on annual harvest data collected by the Washington Department of Fish and Game. Data are displayed as “mean harvest days” and represent the average annual harvest estimations from 2006 to 2008. Harvest data are collected according to the Rafeedie Decision, a federal mandate which gives equal shares of shellfishing rights to tribes and the state. Counts are estimates from aerial and on-the-ground surveys conducted during low tides and known popular dates. Sampling effort remains relatively constant among years, but is only a sample of each year’s actual recreational use of shellfishing beaches. This dataset is therefore critical in determining the relative popularity of beaches for shellfish harvesting.

The map also displays estimated fecal coliform counts at stations surrounding the recreational beaches. Recreational beaches are regulated based on water quality data collected on site. However in 2000, few stations existed at these beaches. We modeled water quality data only for stations with existing data for years 2000 – 2002 (the time period of the 2001 NLCD landcover data). As more current land cover data becomes available, we plan to model fecal coliform at recreational shellfish beaches based on associations between land cover and water quality data collected at these sites.

 

Recreational Beach Quality
  An intersection of beach armoring index scores and recreational visits at State beaches, classified by access type

Variation in beach visitation is often characterized by three main categories describing a recreational site: the site’s amenities and characteristics, the environmental condition, and the demand and access (Termansent et al., 2004). Changes to any of these categories can result in a change in visitation, and therefore a change in the supply of that ecosystem service. In Puget Sound, preferences for nearshore and coastal recreation are likely for sites with a natural condition, in part due to the variety of activities and their reliance on natural habitats (Leschine and Peterson, 2007). The alteration of natural geomorphic processes could have an effect on the characteristics of the Puget Sound coastline. This could reduce recreational visits or the value of an individual visit by changing beach characteristics or by altering habitat quality (Pethick, 2001; Brown and Mclachlan, 2002). Thus the pattern of future land use could negatively alter the physical shore form and affect both human use values and the natural environment.

A comparison of areas where the beach armoring index intersects with areas of high recreational visitation points to areas that may have the largest net changes of recreational ecosystem services. Armoring could alter the coastal environment by disrupting the natural sediment supply necessary for maintaining beaches or for building shellfish and forage fish habitat. While the effects of beach armoring may be present across the Sound, in the recreational context the impacts to State Parks may be strongest at areas that receive many visitors. The area around Port Townsend (inset, figure 3) is one such area that has high visitation to Fort Worden, Fort Flagler, Fort Ebey, and Fort Casey State Parks, and where the parks had a higher than average armoring index value (Port Townsend area = 67,127 mean visits and 1.64 armoring index, overall = 35,753 mean visits and 1.22 armoring index). The beach armoring index shows greater spatial than temporal variation among sites and years. This is partly due to the input LULC scenarios that did not predict large amounts of shoreline armoring in any scenario. Values for the beach armoring index range from zero to five, however a value of 3 was the largest index value at a park. Another reason is the absence of a climate change impact. In future work LULC scenarios should incorporate sea level rise to capture the effect of individuals increasing armoring to counteract increased erosion and storm surge.

Figure 3. An intersection of beach armoring index scores and recreational visits at State beaches, classified by access type"

Beach armoring index scores chart

 

References

Brown, A.C., and A. McLachland. 2002. Sandy shore ecosystems and the threats facing them: Some predictions for the year 2025. Environmental Conservation 29:62-77.

Johannessen, J. and A. MacLennan. 2007. Beaches and Bluffs of Puget Sound. Puget Sound Nearshore Partnership Report No. 2007-04. Seattle District, U.S. Army Corps of Engineers, Seattle, Washington.

Office of Shellfish and Water Protection. 2010. 2009 Annual Report: Commercial and Recreational Shellfish Areas in Washington State. Washington State Department of Health http://www.doh.wa.gov/ehp/sf/Pubs/annual-inventory.pdf.

Penttila, D. 2007. Marine forage Fishes in Puget Sound. Puget Sound Nearshore Partnership Report N. 2007-03. Seattle District, U.S. Army Corps of Engineers, Seattle, WA.

Penttila, D. 1995. The WDFW’s Puget Sound intertidal baitfish spawning beach survey project. Pp. 235-241 in Puget Sound Research-95 Conference Proceedings, Vol. 1. Puget Sound Water Quality Authority, Olympia, Washington.

Pethick, J. 2001. Coastal management and sea level rise. Catena 42:307-322.

Termansen, M., C.J. McClean, and H. Skov-Petersen. 2004. Recreational site choice modeling using high-resolution data. Environment and Planning A 36:1085-1099.

Thom, R. M., D. K. Shreffler, and K. Macdonald. 1994. Shoreline armoring effects on coastal ecology and biological resources in Puget Sound, Washington. Coastal Erosion Management Studies, Volume 7. Shoreland and Coastal Zone Management Program, Washington Department of Ecology, Olympia, Washington. 95 p.

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