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

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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. A Natural Resources Specialist with the City of Portland stated that the City had analyzed Wapato Marsh surface water in about 1993, and found it to be clean, although the he could provide no readily-available copy of the City’s laboratory data.

Because of an elevated surface water level in the marsh at that time of DEQ’s site visit, there were no visual indicators of a leachate seep at the landfill toe. However, the seep was located using continuous surface water conductivity and temperature measurements along the full length of the landfill toe.

DEQ sampled surface water at the seep, and analyzed the water for toxic metals, volatile organic compounds [VOCs], semi-volatile organic compounds [SVOCs], and several general water quality indicator ions. The surface water samples contained detectable concentrations of barium, chromium, and lead, along with

4 elevated concentrations of iron and manganese (see Table 1). Relatively low concentrations of acenaphthene, dibenzofuran, and chlorobenzene were also detected.

Because DEQ lacked risk-based human health or ecological screening values in 1995, analytical results were compared against other water quality indicators, such as Primary and Secondary Drinking Water Standards, leachate characteristics at other western Oregon landfills, and ambient water quality in nearby surface water bodies such as the Willamette and Tualatin Rivers. Contaminant concentrations at the leachate seep were below Primary Drinking Water Standards, although the concentrations of iron and manganese exceeded Secondary Drinking Water Standards by several orders of magnitude.

The landfill had been closed for 25 years by the time that DEQ Site Assessment conducted its site review. Site Assessment concluded that the landfill was probably near the end of its leachate-producing lifespan, and that there was no evidence of significant hazardous substance burials at the site, so it recommended that a No Further Action decision be issued for the site. The site’s No Further Action decision was issued in June 1996.

The concentrations of aluminum, barium, iron, lead, manganese, ammonia, and bis(2-ethylhexyl)phthalate that DEQ detected in Wapato Marsh surface water in August 1995 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.

DEQ Investigation of a 2003 Pipeline Rupture at the landfill Site

In March 2003, a 60-inch diameter drinking water transmission pipeline buried along the landfill’s eastern perimeter ruptured and eroded a sizeable volume of the landfill’s buried wastes (see Figure 6). Additional wastes also had to be excavated to allow a repair crew access and repair the damaged pipeline. The pipeline provides Washington County residents with drinking water from the City of Portland’s Community Drinking Water Supply.

Representatives from DEQ’s Northwest Region Solid Waste Program and Site Assessment Section inspected the pipeline rupture site a week after the incident to determine if hazardous substances were present, and to assess damages to the landfill cap. A photolog of DEQ’s inspection is included as Appendix A.

By the time that DEQ representatives arrived at the site, the City of Portland had already consolidated the disturbed wastes and covered them with plastic tarping. The vast majority of the wastes appeared to be manufactured wood waste and other construction and demolition debris, such as bricks, broken concrete, steel reinforcing mesh for concrete, steel banding, decomposed fiberglass, and bagged cement or mortar. Much of the wood waste was charred. A minor amount of the material appeared to be household wastes, including plastic food wrappers, shoes, hard plastics, toys, foam seat cushions, and a hot water bottle.

There was no obvious indication of wet garbage or significant volumes of hazardous substances in the stockpiled wastes. However, petroleum sheens were visible on standing water at various locations around the stockpiled wastes (see Photos 11 through 13 of Plate B in Appendix A). Examination of the eroded area also indicated that the wastes had been capped with a relatively thin layer of gravelly- to rocky soils, and that the cap was no more than a few inches thick in places (see Photos 16 and 17 of Plate C in Appendix A). DEQ approved transport of the unearthed wastes to a local permitted solid waste landfill for disposal.

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September 2003 USACE Surface Water and Sediment Evaluation

In September 2003, USACE sampled surface water and sediments in the OBWR to examine the feasibility of improving drainage within the wildlife preserve. Two surface water samples that were collected near the major landfill leachate seep (samples 3WLR60001 and #WLR60004) contained concentrations of copper, lead, benzo(a)pyrene, Total PCBs, 4,4’-DDD, 4,4’-DDT, Total DDT, dieldrin, and heptachlor at concentrations that could represent an ecological risk to aquatic life within Wapato Marsh (see Table 2; sampling locations are depicted in Figure 10). A variety of other metals, PAHs, and pesticides were also detected in the two surface water samples, along with detectable concentrations of phthalates, chlorinated hydrocarbons, and N-nitrosodiphenylamine, but at concentrations that were below aquatic screening values. With the exception of most of the phthalates and HPAHs, contaminant concentrations were generally higher near the landfill leachate seep than those detected in surface water nearer the center of the marsh. The landfill leachate may have been a major contributor of contamination in the marsh’s surface water.

A sediment sample collected near the landfill leachate seep contained concentrations of copper, nickel, zinc, acenaphthene, 4,4’-DDD, 4,4’-DDE, and 4,4’-DDT at concentrations that could represent a threat to aquatic life within the marsh (see Table 3). PCBs were also present, but at relatively low concentrations. However, all of these sediment contaminants, with the exception of the PCBs and several PAHs, were found at higher concentrations in sediments near the center of the marsh. Sediments near the landfill leachate seep also contained relatively low concentrations of methylene chloride, 1,4-dichlorobenzene, and N- nitrosodiphenylamine.

The contaminant concentrations that USACE detected in surface water and sediments near the landfill leachate seep in September 2003 suggest that the landfill was contributing contaminants that could represent a threat to wildlife within Wapato Marsh, but that other contamination sources were likely also present.

January 2007 Surface Water Samplings by City of Portland’s Bureau of Environmental Services

In January 2007, the City of Portland’s Bureau of Environmental Services resampled surface water near the landfill leachate seep (sample S-1 of Table 2 and Figure 10), as well as sampling Wapato Marsh surface water at a smaller leachate seep discovered near the landfill’s northeastern corner (sample S-2 of Figure 10).

Surface water at both locations contained chromium, copper, lead, and nickel at concentrations that could represent an ecological threat to aquatic wildlife in Wapato Marsh (see Table 2). Metals concentrations were consistently higher near the larger western leachate seep. Surface water at the western seep also contained mercury and silver at concentrations above ecological risk screening levels, while both metals were undetected near the smaller eastern leachate seep.

Surface water at both leachate seep locations also contained detectable concentrations of LPAHs, chlorobenzene and N-nitrosodiphenylamine. Motor oil, heavy fuel oil, and bis(2-ethylhexyl)phthalate were detected in surface water only near the smaller eastern leachate seep.

2009 Surface Water Sampling by City of Portland’s Bureau of Environmental Services

The City of Portland’s Bureau of Environmental Services conducted a follow-up surface water sampling near

6 the landfill’s larger western leachate seep early in 2009. Water analyses detected metals, diesel fuel, LPAHs, chlorobenzene, and N-nitrosodiphenylamine, but the metals concentrations were substantially lower than those detected in 2007; several metals were detected at one- to three orders of magnitude lower concentration. It is unclear why the surface water metals concentrations would vary so greatly, unless the metals may be associated with suspended particulates that might vary with leachate flow rate.

January 2009 Landfill Soil Borings

In January 2009, the City of Portland’s Bureau of Environmental Services advanced four pushprobe borings into the landfill subsurface (see Figure 11), and collected subsurface soil samples for laboratory analysis. The soil boring depths ranged from 5- to 35 feet below ground surface [bgs]. Boring OB-GP-2, nearest the landfill’s main leachate seep, was terminated at 5 feet bgs because of refusal caused by buried concrete. Groundwater was encountered at depths ranging between 6- and 8 feet bgs, although groundwater samples were not collected for laboratory analysis. Locations of the borings are depicted in Figure 11; soil boring lithologies are summarized in Table 5.

Landfill cover material appeared to be 11- to 30 inches thick, and comprised of low-plasticity silt. Low- plasticity silt may not provide adequate protection against rainwater infiltration. Wastes were encountered to depths of at least 25 feet bgs. Wood debris was encountered in each of the borings. Wood debris from two of the four borings was black, suggesting potential historic landfill fires. Additional wastes that were encountered included concrete, brick, glass, wallpaper, ash, wire, paper, cardboard, yarn, carpeting, upholstery, tin foil, rubber, and metal shavings. Wastes that were encountered suggest that landfill probably received construction and demolition debris, household wastes, and possibly some industrial wastes.

Soil samples from the upper 5 feet of the fill contained elevated concentrations arsenic, cadmium, chromium, and lead (see Table 4). A sample collected from boring OB-GP-4 at 15-30 feet bgs contained 4,4’-DDD, technical chlordane, alpha-chlordane, and gamma-chlordane. The concentrations of cadmium, chromium, lead, DDD, and chlordane in some of the subsurface soils exceed DEQ Stormwater Source control Screening Levels, and could represent a potential threat to surface water and sediments if mobilized.

It is unclear if the pesticides detected in the 15-30 foot interval from boring OB-GP-4 represent contaminants within the landfill wastes, or pesticides that may have been present in pond sediments prior to landfilling. Wastes at this boring may have extended no deeper than about 25 feet bgs, according to the boring lithology (see Table 5).

Potential Contaminants of Concern:

Contaminants that have been detected above ecological screening levels in surface water or sediments near the landfill leachate seeps include aluminum, barium, chromium, copper, iron, lead, manganese, mercury, nickel, silver, PCBs, acenaphthene, benzo(a)pyrene, DDD, DDE, DDT, dieldrin, heptachlor, bis(2- ethylhexyl)phthalate, and ammonia. Contaminants detected at elevated concentrations in landfill soils and wastes include arsenic, cadmium, chromium, lead, phenanthrene, DDD, and chlordane.

Other contaminants have also been repeatedly detected at lower concentrations in surface water and sediments near the landfill leachate seeps. These contaminants include chlorobenzene, N- nitrosodiphenylamine, diesel fuel, heavier fuel oil, motor oil, and various LPAHs and HPAHs.

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No analyses have been conducted to determine whether asbestos may be present in the landfill wastes.

Local Geology, Hydrology, and Hydrogeology:

The site is located on Quaternary alluvium of the Willamette River floodplain (see Figure 12), which is generally comprised of mixed layers of silt, sand, and gravel. A nearby boring at the Oaks Amusement Park encounter basalt (probably severely scoured Waverly Heights basalt of the Eocene) at about 95 feet bgs. Waverly Heights basalt is typically blocky to columnar-jointed with vesicular flow tops. However, the Portland Hills Fault lies just over ½ mile east-northeast of the site. A boring at Sellwood Park, atop the eastern escarpment, encountered fractured basalt from 61- to 540 feet bgs, so the local basalt probably does not limit vertical groundwater flow.

The eastern bluff is comprised of coarse sand and silt of the Pleistocene catastrophic floods, which is overlain in localized areas toward the southeast (see Figure 12) by pebble- to boulder sized gravel in a matrix of silt and coarse sand. The land surface on top of the bluff generally slopes to the east, toward Crystal Springs Creek, 0.8 mile east of the landfill site (see Figure 12). Crystal Springs Creek is oriented on a north/south axis, and drains to Johnson Creek, about 0.6 miles to the south. Most rainfall runoff atop the bluff is probably captured by combined sewers, which drain either to the east, or south. However, sewers are absent west of SE 7th Avenue; municipal sewers do not capture stormwater runoff at Sellwood Park.

Wapato Marsh was formed when a railroad trestle from the early 1900’s along the Willamette River’s eastern bank was replaced by an earthen berm. The wetland area is fed by Willamette River floodwaters, as well as groundwater emitting from a series of small springs along the base of the eastern escarpment, and numerous stormwater culverts along the top of the escarpment. To improve area drainage, the U.S. Army Corps of Engineers [USACE] installed a 60-inch diameter culvert through the railroad berm, connecting Wapato marsh to the Willamette River. The culvert is located about 300 feet north of Wapato Marsh. To manage seasonal water levels within Wapato Marsh, in 1991, the City of Portland installed a water control structure near the landward opening of the USACE culvert. The control structure is comprised of a small dam with 13 six-inch removable “stop logs”. Water levels are controlled by removing or adding boards at various times throughout the year.

The Federal Emergency Management Agency [FEMA] has mapped as much as the northern 350 feet of the landfill site within either the 100- or 500-year Willamette River flood zone.

U.S. Geological Survey [USGS] estimates of groundwater elevations in the Sellwood area indicate that local groundwater elevations should be highest at a well in Sellwood Park. Locally, shallow groundwater should generally flow to the east and southeast, toward Crystal Springs Creek, except in the immediate vicinity of the escarpment east of the landfill site (see Figure 13). Shallow groundwater at Sellwood Park should flow to the northwest, toward the landfill. The USGS groundwater flow model predicts that shallow groundwater at the landfill likely flows to the north, toward Wapato Marsh. Static groundwater water levels within the landfill may be directly related to surface water elevations within Wapato Marsh.

A bathymetric chart from the National Oceanic and Atmospheric Administration [NOAA] indicates that, nearest the landfill site, the Willamette River is up to 95 feet deep. It appears very unlikely that shallow groundwater from the site could migrate beyond the river. Surface water in Wapato Marsh drains to Holgate

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Slough, a braid of the Willamette River on the east side of Ross and Hardtack Islands. NOAA bathymetric charts indicated that surface water depth in Holgate Slough ranges between about 7- and 31 feet deep.

Local Land Use:

Properties atop the eastern escarpment are predominantly residential. The lower lying floodplain is predominantly wetlands of the OBWR, with municipal park land, a commercial amusement park, a yacht club, and about 40 houseboats moored along the river. The City of Portland has zoned Oaks Amusement Park and the Oregon Yacht Club properties as residential farming zone.

Local Water Use:

Residents of the Sellwood area are supplied with drinking water from the City of Portland’s Community Drinking Water Supply [CDWS], which uses surface water from the Bull Run Reservoirs on the northwestern slope of Mount Hood, 32 miles to the east, and groundwater from deep wells along the Columbia River, 10- to 13 miles to the northeast.

Groundwater:

Oregon Water Resources Department [OWRD] and USGS have records for five wells within about 850 feet of the landfill site. Two of the wells are located at Sellwood Municipal Park: one near the park’s northeast corner, and one near the park’s southwest corner. Both wells have Water Rights for municipal use of groundwater, although OWRD has a well log for only the southwestern well.

The southwestern well is 560 feet deep and withdraws groundwater from both fractured basalt (at 220- to 487 feet bgs) and underlying claystone (at 560 feet bgs). The static water level [SWL] in this well was 91 feet bgs, about 14 feet higher elevation than groundwater at the landfill site, when the well was constructed in 2000. However, continuous pumping at this well is capable of drawing down the water table at least 225 feet, about 120 feet lower than the groundwater level at the landfill. The park’s southwestern well may be capable of intercepting potentially contaminated groundwater from the landfill site.

Sellwood Park’s northeastern well has an average SWL of 109 feet bgs, about 22 feet higher than the water table at the landfill. Although both park wells have Water Rights for municipal use, the wells are likely used only for lawn irrigation. City utility mapping indicates CDWS connections at four locations within the park. One of the CDWS connections feeds water to the park’s public swimming pool.

USGS also has records for a 137 foot deep well located less than 300 feet east of Sellwood Park. Although the well was constructed in 1994, groundwater use at the well is unknown. Depth to water in the well was 107 feet bgs when the well was constructed, about 20 feet higher than the groundwater table at the landfill site.

Well logs are available for two wells at the Oaks Amusement Park, 520- to 760 feet west of the landfill site. The wells are 83- and 84 feet deep, and withdraw groundwater from recent alluvium. SWLs within the two wells were recorded as 11- and 12 feet bgs. Only one of the wells has a Water Right, for non-contact groundwater use for an air conditioning unit. One of the wells was proposed for irrigation use when it was constructed. Potential contaminated groundwater at the landfill site could represent a threat to water quality

9 at the Oaks Amusement Park’s shallow wells.

City utility mapping indicates that neither the Oaks Amusement Park property, nor the Oregon Yacht Club property and houseboats to the north, have access to the CDWS. The drinking water source for these properties is unknown. Oregon Health Division has no records to indicate that either Oaks Amusement Park or the Oregon Yacht Club are Public Drinking Water sources.

The city has municipal use Water Rights for two additional wells at Westmoreland Municipal Park, about one mile east of the landfill site. These wells are also likely used for lawn irrigation. The nearest designated domestic use well are three wells located about 1.75 miles northeast of the landfill site. The nearest CDWS wells are six wells that belong to the City of Milwaukie, about 2.25 miles southeast, and upgradient, from the site.

Surface Water:

There is no record of drinking water use of the Willamette River within two miles of the landfill site. The nearest Water Rights for domestic use of surface water are located along Crystal Springs Creek, about 0.9 mile east of the landfill site, and from an unnamed stream about 2 miles northeast from the site. Both surface water bodies lie upstream from the landfill site.

Nearest the site, the Willamette River provides important rearing and migration habitat for summer and winter steelhead trout, spring and fall Chinook salmon, and Coho salmon. Lower Columbia steelhead trout, Lower Columbia River Chinook salmon, and Upper Willamette River Chinook salmon are federally-listed Threatened Species. Coho salmon is an Oregon-listed Endangered Species. The State of Oregon has designated this reach of the river as Essential Salmon Habitat. The National Marine Fisheries Service [NMFS] has designated the Willamette River reach as Critical Habitat for salmonids.

Other significant fish identified within the Lower Willamette River include searun cutthroat trout, Pacific lamprey, white sturgeon, and starry flounder. Searun cutthroat trout and Pacific lamprey are federally- designated Species of Concern.

Fish are capable of entering Wapato Marsh from the river during high flow events, although the city’s water control structure north of Wapato Marsh can prevent fish from re-entering the river as water levels recede. USACE’s proposed revisions to the culvert and water control structure should improve egress of fish trapped in the marsh.

Other Sensitive Species and Habitat:

The U.S. Fish and Wildlife Service [USF&W] has mapped approximately 95 acres of wetlands within about 2 miles downgradient from the landfill site (see Figure 14). Wapato Marsh and areas to the north, within the OBWR, are parts of an 81.4 contiguous acre wetlands area.

The Portland Audubon Society has identified more than 150 species of birds within the OBWR. Many of these species are migratory, and are protected by international treaty. Some of the species that have been identified include bald eagles, peregrine falcons, band-tailed pigeons, olive-sided fly catchers, purple martins, western meadowlarks, pileated woodpeckers, and little willow flycatchers. The bald eagle was

10 recently federally de-listed as a Threatened Species, although it is still protected under the federal Bald and Golden Eagle Protection Act. A pair of bald eagles is known to nest along the western fringe of Ross Island, 0.9 mile north-northwest of Wapato marsh. Oregon continues to list the bald eagle as a Threatened Species. Oregon also considers the peregrine falcon an Endangered Species, although it has no federal protective status. The band-tailed pigeon, olive-sided fly catcher, and purple martin are federally- designated Species of Concern. Oregon has designated the western meadowlark a Critical Species, and the pileated woodpecker and little willow flycatcher as Vulnerable Species.

The northern portion of the OBWR has been identified as habitat for the northern red-legged frog, a federal Species of Concern. Several other sensitive species have been identified within the same river reach as the landfill site, although specific habitat within the OBWR has not been identified. These species include the tri-colored blackbird, the northwestern pond turtle, the fringed myotis, the long-eared myotis, and the long- legged myotis. All are federal Species of Concern.

The Portland Audubon Society has also observed as many as 50 great blue herons feeding in Wapato Marsh at one time. A major heronry is located along the western bank of Ross Island Lagoon, about 0.9 mile north- northwest of Wapato Marsh. Analysis of eggs collected from six colonies of great blue herons in Oregon and Washington in 1994-95 found that egg shells from the Ross Island heronry contained substantially higher concentrations of p,p’-DDE, Total PCBs, and trans-nonachlor than eggs shells from the five other locations, as well as some of the highest concentrations of polychlorinated dioxins. Eggs from the Ross Island heronry also had the thinnest shells of all six sampling locations. Some of this contamination might be attributable to consumption of potentially contaminated food in Wapato Marsh.

Vulnerable Areas:

The Oaks Bottom Landfill site lies within four Site Discovery Vulnerable Areas:

The site lies within the Lower Columbia River Estuary, which includes the Lower Willamette River as far upstream as the falls at Oregon City, and all downstream tributaries.

Locally significant wetlands are present within OBWR.

Oregon DEQ added the Lower Willamette River to its 303(d) list of Water Quality Limited surface water bodies because of year-around elevated concentrations of a broad variety of toxic metals, PAHs, organochlorine pesticides, PCBs, dioxins, and nutrients.

The Oregon Health Division issued fish consumption advisories for the Willamette River in 1999, 2000, and 2001 because of elevated concentrations of mercury, PCBs, dioxins, and organochlorine pesticides in the tissue of fish caught from the river.

Discussion:

Hazardous substances are present in subsurface soils and wastes at the Oaks Bottom Landfill site. Analyses of Wapato Marsh surface water and sediments near the landfill’s leachate seeps suggest that the landfilled wastes may be adversely affecting aquatic life within the marsh. Dead trees near the landfill’s main leachate 11 seep further suggest that there may be some phytotoxicity associated with the leachate.

Aerial photos depict a discolored leachate plume that, at times, appears to be up to 250 feet long. The apparent plume length suggests that, at times, leachate may be entering the marsh at relatively high velocity, and could be emitting from a subsurface drainage pipe.

Groundwater has been encountered a very shallow depths within the landfill, although there is no evidence that the groundwater has ever been analyzed for potential hazardous substances. The sources for drinking water at nearby properties such as Oaks Amusement Park, the Oregon Yacht Club, and nearby houseboats, are unknown. City utility diagrams indicate that the properties are not supplied with water from Portland’s Community Water Supply. Oaks Amusement Park has two wells, although neither is registered as a Public Drinking Water Supply. There are no records of any well being located on the Oregon Yacht Club property, although OWRD did not require registration of newly constructed wells until about 1958. Further investigation is needed to determine whether potentially-contaminated groundwater at the landfill could be adversely affecting nearby drinking water supplies.

The City of Portland and USACE have proposed removing some of the contaminated soils and sediments near the OBWR drainage culvert, reconstructing the culvert to improved fish passage, and upgrading salmonid habitat within the lower marsh. Site Assessment is concerned that contaminated surface water and sediments near the landfill could have an adverse affect on sensitive fish within the proposed habitat improvement area.

Although DEQ Site Assessment issued a No Further Action decision for the landfill site in 1996, newer test data and more-recently-developed Risk-Based Screening Standards for human health and the environment indicate that further investigation of the landfill site is needed.

Recommendations:

It is recommended that DEQ’s 1996 No Further Action decision for the Oaks Bottom landfill site be rescinded, and that further investigation of the site’s groundwater, soil, and waste composition be conducted.

A high priority is assigned to further investigation of hazardous substance contamination within the landfill site, and cleanup of contaminated sediments along the landfill’s north toe. Additional investigation is also needed to determine whether subsurface drainage piping may present in the landfill subsurface.

Existing soil, sediment, and surface water test data further indicate that the site warrants addition to DEQ’s Confirmed Release List (CRL) and Inventory of sites requiring further investigation and cleanup.

Referrals Within or Outside DEQ:

This site review was conducted under a cooperative site assessment agreement with the U.S. Environmental Protection Agency [USEPA]. DEQ reserved the option of referring the site to USEPA for future follow-up.

Other:

Based on a review of the site reports and other information sources referenced in this document, this

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Strategy Recommendation represents a state Preliminary Assessment Equivalent [PAE] of the Oaks Bottom Landfill site. The site is currently included on DEQ’s ECSI database; the database will be updated with information contained within this document, and to reflect Site Assessment’s decision for further action at the site. The site is also recommended for proposed addition to DEQ’s CRL and Inventory of sites requiring further investigation and cleanup, based on contaminants that have been detected in landfilled wastes, and in surface water and sediments near the site’s leachate seeps.

Attachments:

Table 1: Wapato Marsh Surface Water Quality – 1987-1995 (DEQ)

Table 2: Summary of Recent Oaks Bottom Surface Water Analytical Results

Table 3: Oaks Bottom Sediment Analysis Results

Table 4: Oaks Bottom Landfill Soil Analysis Data

Table 5: Soil Boring Lithologies – Oaks Bottom Landfill

Figure 1: Oaks Bottom Landfill site located on a 1:100,000 USGS metric topo map

Figure 2: Oaks Bottom Landfill site located on a 7.5 minute USGS topo map

Figure 3: Oaks Bottom Landfill site located on an ODOT highway map

Figure 4: Oaks Bottom Landfill site depicted in a 2007 City of Portland aerial photo

Figure 5: Oaks Bottom Landfill site depicted on a Tax Lot diagram overlay from City of Portland Corporate GIS

Figure 6: Air photo depicting locations of the landfill site’s Solid Waste Holding Area and March 2003 Drinking Water Transmission Pipeline rupture

Figure 7: Oaks Bottom Landfill site depicted in a Portland Parks and Recreation Department diagram of Oaks Bottom Wildlife Refuge

Figure 8: Oaks Bottom Landfill leachate seep depicted in an October 2002 photo by City of Portland

Figure 9: Photographic depictions of a leachate seep along the Oaks Bottom Landfill’s northern toe

Figure 10: Air photo depicting 2003 through 2009 surface water and sediment sampling locations

Figure 11: Air photo depicting landfill subsurface soil sampling locations in 2009

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Figure 12: Generalized geology in the vicinity of Oaks Bottom Landfill.

Figure 13: USGS-estimated groundwater elevations near the Oaks Bottom Landfill site

Figure 14: Local wetlands defined by U.S. Fish and Wildlife Service

Appendix A: Photolog of March 2003 Drinking Water Transmission Pipeline Rupture

References:

The following general references were consulted in preparing this Strategy Recommendation:

1. Oaks Bottom Wildlife Refuge Restoration Project, Sediment Evaluation Framework, Level-1 Dredge/Sediment Assessment, Township: 1S, Range: 1E Section: 14CD in the Sellwood Neighborhood, Portland, Oregon 97202, BES Project 8576, CSA 737, prepared by City of Portland, Bureau of Environmental Services, Coordinated Site Analysis Program, for City of Portland, Bureau of Environmental Services, Engineering Services, August 31, 2007.

2. September 12, 2007, Letter from Scott Clements, P.E., Project Manager, City of Portland Bureau of Environmental Services, to Kathryn Harris, U.S. Army Corps of Engineers, Portland, Oregon, Subject: Oaks Bottom Habitat Enhancement Project.

3. The Landfill Legacy, Portland Metropolitan Area Landfills Closed since 1960 and their impact on the Region’s Urban and Natural Environment, prepared by Engineering and Environmental Services, Metro Solid Waste and Recycling Department, March 2004.

4. Oaks Bottom Landfill Data, summary of analytical results from January 2009 soil borings at Oaks Bottom Landfill, response to DEQ Site Assessment Information Request, from Taryl Meyer, City of Portland Bureau of Environmental Services, Coordinated Site Analysis Program, May 18, 2009.

5. Summary of Surface Water Analytical Results, summary of analytical results from 2003, 2007, and 2009 surface water samplings at Oaks Bottom Wildlife Refuge, response to DEQ Site Assessment Information Request, from Taryl Meyer, City of Portland Bureau of Environmental Services, Coordinated Site Analysis Program, May 18, 2009.

6. Summary of Sediment/Soil Analytical Results, summary of analytical results from soil and sediment samplings at Oaks Bottom Wildlife Refuge, personal communication from Taryl Meyer, City of Portland Bureau of Environmental Services, Coordinated Site Analysis Program, May 18, 2009.

7. TerraServer-USA, http://terraserverusa.com/

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8. ODOT highway maps, http://www.oregon.gov/ODOT/maps.shtml

9. PortlandMaps, http://www.portlandmaps.com/

10. OWRD well log database, http://apps2.wrd.state.or.us/apps/gw/well_log/Default.aspx

11. OWRD Water Rights Information System [WRIS] database, http://apps2.wrd.state.or.us/apps/wr/wrinfo/

12. USGS, Ground-Water and Water-Chemistry Data for the Willamette Basin, Oregon, http://or.water.usgs.gov/pubs_dir/Cd/WRIR99-4036/index.html

13. USGS National Map Viewer, wetlands, http://nmviewogc.cr.usgs.gov/viewer.htm

14. USF&W National Wetlands Inventory, Wetlands Mapper, http://www.fws.gov/wetlands/Data/mapper.html

15. ODF&W, Natural Resources Information Management Program, Fish Distribution Maps, http://nrimp.dfw.state.or.us/nrimp/default.aspx?pn=fishdistmaps

16. USF&W, Critical Habitat Mapper, http://crithab.fws.gov/

17. Oregon Secretary of State, Corporate Division Database, http://egov.sos.state.or.us/br/pkg_web_name_srch_inq.login

18. NOAA 1:20,000 Bathymetric Chart 18526, Port of Portland, including Vancouver, U.S. Department of Commerce, 1984.

19. USDA SCS Soil Survey of Multnomah County, Oregon, http://www.or.nrcs.usda.gov/pnw_soil/or_data.html

20. Federal Emergency Management Agency flood insurance rate mapping, Panel 4101830181E, Portland, Oregon, http://map1.msc.fema.gov/idms/IntraView.cgi?ROT=0&O_X=7091&O_Y=5117&O_ZM=0.03908 5&O_SX=554&O_SY=399&O_DPI=400&O_TH=99135913&O_EN=99135913&O_PG=1&O_M P=1&CT=0&DI=0&WD=14182&HT=10234&JX=991&JY=549&MPT=0&MPS=0&ACT=0&KE Y=99124731&ITEM=1&ZX1=490&ZY1=278&ZX2=549&ZY2=344

21. M.H. Beeson, er.al., Geologic Map of the Lake Oswego Quadrangle, Clackamas, Mulnomah, and Washington Counties, Oregon, Oregon Department of Geology and Mineral Industries, Publication GMS-59, 1989.

22. Estimated Depth to Ground Water and Configuration of the Water Table in the Portland, Oregon Area, U.S. Geological Survey Scientific Investigations Report 2008–5059, by Daniel T. Snyder, 2008, http://pubs.usgs.gov/sir/2008/5059/pdf/sir20085059.pdf

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23. Oaks Bottom Wildlife Refuge, Portland Parks and Recreation Department, http://www.portlandonline.com/parks/finder/index.cfm?action=ViewPark&PropertyID=490&sear chtext=oaks%20bottom

24. South Escarpment Unit, Nature in the City, Portland Parks and Recreation Department, http://www.portlandonline.com/parks/index.cfm?c=47583

25. Bird List for Oaks Bottom Wildlife Refuge, Portland Migratory Birds, Portland Parks and Recreation Department, http://www.portlandonline.com/portlandmigratorybirds/index.cfm?&c=35118&a=55189

26. Wild in the City, A Guide to Portland’s Natural Areas, edited by Michael C. Houk and M.J. Cody, Oregon Historical Society Press, Portland, Oregon, 2000.

27. Environmental Contaminants in Great Blue Herons (ARDEA HERODIAS) from the Lower Columbia and Willamette Rivers, Oregon and Washington, USA, by C.M. Thomas and R.G. Anthony, Environmental Toxicology and Chemistry, Volume 18, Number 12, 1999.

28. Field and Data Report, Downtown Portland Sediment Characterization, Willamette River, Portland, Oregon, prepared for Oregon Department of Environmental Quality, by Water Solutions, Inc., January 2009.

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