VI. D. 2. Regional Focus - Bainbridge Island |
Industrial contamination on Bainbridge Island is largely confined to the Wycoff creosote wood treatment facility at the mouth of Eagle Harbor. Elevated levels of PAHs, a component of creosote, were discovered in Eagle Harbor in 1984 (U.S. Army Corps of Engineers 2001b). Other toxins besides PAHs reported to be found in Eagle Harbor are naphthalene, flouranthene, acenaphthalene, phenanthrene, anthracene, flourene, PCB-1254, benzo(a)pyrene, benzo(a)anthracene, chrysene, benzo(k)flouranthene, dibenzo(a,h)anthracene, ideno(1,2,3‑c,d)pyrene. These toxins far exceed the sediment management standards for marine sediment (U.S. Army Corps of Engineers 2000). PAH contamination is also known to occur in Blakely Harbor (Jones and Stokes Associates 1992).
Point-source pollution on Bainbridge Island has historically been concentrated near active or recently active sewer outfalls located at Wing Point, Skiff Point, Lynwood Center, and Fort Ward State Park (Figure VI-17). None of these are combined sewer outfalls, which combine sewer and stormwater flows within the same system. Current shellfish harvesting closure advisories exist in the vicinity of these outfalls (Kitsap County Health District 2002). Two of the currently operating outfalls service secondary treatment facilities: the Bainbridge Island municipal treatment facility, which discharges at Wing Point on the north of Eagle Harbor, and the Kitsap County Sewer District # 7 treatment facility, which discharges near Fort Ward State Park at the south of the Island. A small, privately owned treatment facility that services an adult convalescent home (Messenger House) discharges sewage from an outfall located off of Skiff Point. We are currently unaware of its treatment level, although it is likely primary because of the age of the system. The Lynnwood Center outfall, which discharged into Rich Passage, was closed in 1999, and services were combined with the Fort Ward treatment facility. Bainbridge Island is currently proposing a sewer plan for the south end of the Island that includes expansion of services to shoreline areas, including Point White and Rockaway Beach (P. Best, COBI, personal communication, 2002).
Figure VI-16. Outfall locations for Bainbridge Island (Source: WA Dept of Health, 2001)
The majority of NPS pollution on Bainbridge Island comes from stormwater runoff and a small amount of agricultural activity (Grellner et al. 1997). The relatively small drainage basins that exist on Bainbridge Island may carry contaminants into nearshore areas in higher concentrations than watersheds with larger basins. Contaminants traveling smaller distances and the lower water volumes of smaller urban drainages result in reduced dilution potential. Although development has increased in recent years, sediment contamination has decreased. Sediment sampling in 1997 and 2000 of nearshore areas around Bainbridge Island and throughout the Central Puget Sound observed a decrease in contaminant concentrations from prior sampling events, possibly a result of improvements in waste-management technologies, cleanup of contaminated sites, and natural processes (Long et al. 2000; Grellner et al. 1997).
Many private residences on Bainbridge Island use single-family septic systems, and a number of embayments house marinas and houseboats. These residential land and aquatic uses have the potential to contribute wastewater discharges into the nearby waters, especially when septic systems fail or are not maintained adequately. Almost all benthic sediment contains some level of contamination from wastewater and stormwater inputs from past and/or current anthropogenic activities (Puget Sound Water Quality Action Team 2001).
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