DEQ SITE ASSESSMENT PROGRAM - STRATEGY RECOMMENDATION Site Name: Oaks Bottom Landfill CERCLIS Number: [ None ] DEQ ECSI Number: 1006 Site Address: South Meadow, Oaks Bottom Wildlife Refuge Tax Lot 100 (T1S/R1E-S23) Portland, OR 97202 Recommendation By: Steve Fortuna, Site Assessment Section, DEQ Northwest Region Approved By: Bruce Gilles, Northwest Region Cleanup and Emergency Response Manager Date: June 22, 2009 Site Contacts: John O’Donovan City of Portland, Bureau of Environmental Services, Coordinated Site Analysis Program 1120 SW 5th Avenue, Room 1000 Portland, OR 97204-1912 503-823-7881 Jan Betz City of Portland, Deputy City Attorney 1221 SW 4th Avenue, Suite 430 Portland, OR 97204-1900 503-823-4047 Taryn Meyer City of Portland, Bureau of Environmental Services, Coordinated Site Analysis Program 1120 SW 5th Avenue, Room 1000 Portland, OR 97204-1912 503-823-5861 1 Background: The Oaks Bottom Landfill site was among the initial group of sites that DEQ added to its Environmental Cleanup Site Information [ECSI] database in 1988 because of suspected hazardous substance contamination. DEQ initiated a Federal Site Screening of the site in August 1995. Existing DEQ records contained very little information about the landfill’s history, so the site evaluation was based largely on results of an on-site inspection and an analysis of leachate that was seeping from the toe of landfill into an adjoining marshland. Based on results of the site review, and environmental regulatory standards in effect at that time, DEQ concluded that the landfill represented little significant threat to human health or the environment. A No Further Action decision was issued for the site in June 1996. Additional environmental test data collected at the site in 2000 through 2009, along with recent development of more-detailed human health and ecological risk-based screening standards, indicate that leachate that continues to be released by the former landfill may represent a potential risk to aquatic life within the Oaks Bottom Wildlife Refuge. Based on the new site information and improved risk-evaluation standards, the site warrants re-evaluation and re-prioritization by DEQ Site Assessment. Site Location: The former Oaks Bottom Landfill is an approximate 9.6 acre, triangular-shaped tract of land located in southeast Portland, within the southern end of the City of Portland’s 168-acre Oaks Bottom Wildlife Refuge [OBWR]. The site is located on the eastern floodplain of the Willamette River, near River Mile 16.1, about 2.5 River Miles upstream from downtown Portland (see Figures 1 through 3). The site is bordered on the north by Wapato Marsh, a 60-acre, seasonally-inundated wetlands area of the OBWR, and on the west by a right-of-way for East Portland Branch of the Oregon Pacific Railroad Company (see Figure 4). Metro’s Springwater Corridor Recreational Trail parallels the western edge of the railroad right-of-way. Oaks Park, a privately-owned, commercial amusement park, lies farther to the west, just beyond the recreational trail and railroad right-of-way. The Willamette River lies farther to the west, just beyond Oaks Amusement Park. The Oregon Yacht Club and approximately 40 houseboats are located at the downstream end of Oaks Amusement Park. The eastern edge of the landfill lies along the base of a 100-foot high bluff. Sellwood Municipal Park and Portland’s Sellwood residential neighborhood lie at the top of the bluff. General Site Description: The site is predominantly located within the southern tip of Tax Lot 100 of Township 1 South / Range 1 East – Section 23 [T1S/R1E-S23], although as much as 1/3 of the site extends eastward onto portions of Tax Lot 400 (T1S/R1E-S23), Tax Lot 500 (T1S/R1E-S23), and a pair of abandoned roadways (Deed 1848-316; Ordinance 106072)(see Figure 5). Each of these properties is owned by the City of Portland. Portland Parks and Recreation Department [PP&R] literature usually refers to the landfill site as the OBWR’s “South Meadow”. The city is actively restoring the South Meadow area as native grassland. The site is relatively flat with slight undulation, and is predominantly vegetated with perennial grasses and a few shrubs and small trees. The site surface is more uneven near its southern apex. Several relatively deep potholes are present at the southern apex. The site generally has a gentle downward slope toward the north and northeast, toward Wapato Marsh. Surface elevations range between about 43 feet above mean sea level [MSL] near the southwest edge of the site, and about 23 feet MSL near the site’s northeast corner. The 2 western perimeter of the site slopes upward toward a berm supporting the Oregon Pacific Railroad tracks. A solid waste holding area, operated by PP&R, was located at the southern apex of the site until 2006 (see Figure 6). The city used the holding area for temporary storage of tree limbs, brush, other cleared vegetation, excess soils, broken paving material, and other relatively inert materials. Gravelled public recreational hiking trails traverse the site’s northern and eastern perimeters, and a narrow dirt trail traverses the property’s north/south midline (see Figures 6 and 7). Several leachate seeps can be observed along the landfill’s northern toe when the surface water elevation in Wapato Marsh is low. The largest seep is located near the midpoint of the site’s northern boundary (see Figures 8 and 9). Several large trees in the general vicinity of the leachate seep are dead. At least three smaller seeps are located along the eastern half of the northern toe. Tire carcasses and small amounts of concrete debris can be found along the landfill toe. Site Access: The landfill site can be accessed by any of four routes: A 0.25-mile long, city-owned, restricted-use, gravel access road approaches the site from the south. The road has a lockable entrance gate a short distance north of the intersection of SE Spokane Street and SE Grand Avenue (see Figure 3), and was previously used by City of Portland maintenance crews to access the solid waste holding area at the southern end of the site. A pedestrian underpass beneath the Oregon Pacific Railroad right-of-way allows direct pedestrian access to the northwest corner of the site from either the Springwater Corridor Trail or Oaks Amusement Park (see Figures 6 and 7). Recreational trails originating at Sellwood Park’s northern parking lot, near the intersection of SE 7th Avenue and SE Malden Street, reaches the site’s central eastern edge and southern apex after descending the 100-foot high escarpment (see Figure 7). A 2.25 mile recreational trail, originating at the OBWR parking lot, near the intersection of SE Mitchell Street and SE Milwaukie Avenue, reaches the northeast corner of the site after passing along the eastern edge of the wildlife refuge and Wapato Marsh (see Figure 7). Site History: The Oaks Bottom Landfill, originally known as the Sellwood Dump, is believed to have operated from sometime in the late 1950’s through the end of December 1970. The landfill very likely has no underliner, and was neither permitted nor inspected by the Oregon Sanitary Authority, DEQ’s predecessor agency, while it operated. Wastes are believed to have been disposed directly into the southern end of a pre-existing pond or marshland (Wapato Marsh). From about 1967 to 1969, LaVelle Construction Company managed the fill under contract with the City of Portland. At the time, wastes were comprised primarily of demolition and construction debris, street 3 sweepings, and brush and stumps from throughout Portland Metro area, Lake Oswego, and Beaverton. Garbage, car bodies, tires, and animal carcasses were specifically excluded from the fill. According to the landfill operator, incoming wastes were closely monitored, although waste delivery rates were as high as one load per minute. Because of inadequate waste compaction, internal fires were common while the landfill operated. Landfill cover material was both provided by the City of Portland, and purchased from local excavators. The City of Portland acquired the property from the Donald M. Drake Company at the beginning of 1969 to block future industrial development. Rehabilitation of the natural wetland area was begun in the early 1970s, and in 1988, the city designated the site and surrounding area as a wildlife refuge. The City applied several inches of topsoil to the site to improve vegetation growth. Environmental Investigations and Samplings: November 1987 Surface Water Sampling by DEQ DEQ analyzed Wapato Marsh surface water in November 1987 in response to concerns voiced by several local residents and the local Soil and Water Conservation District. DEQ collected a single surface water sample near a leachate seep along the landfill’s north toe, and analyzed the sample for standard landfill leachate indicator parameters. The sample had elevated color, and contained somewhat elevated concentrations of dissolved iron, dissolved manganese, chemical oxygen demand [COD], and total organic carbon [TOC] (see Table 1). It was unclear to DEQ if this necessarily indicated a landfill leachate problem, or may have been attributable, in part, to the wetlands environment. DEQ took no further action at that time, but added the site to its ECSI database of sites requiring further investigation. The concentrations of iron, manganese, and ammonia that DEQ detected in Wapato Marsh surface water in November 1987 exceeded DEQ’s current Ecological Risk Assessment Screening Values for freshwater aquatic life (see Table 1), and could have had an adverse affect on wetland wildlife. 1995 Federal Screening and Surface Water Sampling by DEQ DEQ Site Assessment initiated a Federal Screening of the landfill site in August 1995. Site Assessment’s evaluation included a review of existing DEQ file material for the site, interviews with DEQ Solid Waste Engineers familiar with site history, discussions with City of Portland, a review of nearby receptors, an on- site inspection, and analysis of Wapato Marsh surface water near an underwater leachate seep at the landfill’s northern toe.