Site Description
This section provides a description of the physical features, hydrology, climate, winds, and oil spill risks found in the Green River/Duwamish GRP planning area.
The Green River/Duwamish planning area starts in the headwaters of the Green River in the Cascade Mountains near Stampede Pass in the Okanogan-Wenatchee National Forest. The Howard A. Hanson Dam blocks the river’s flow and creates a reservoir 64 river miles upstream of where the river enters Puget Sound in Seattle at Elliott Bay.
Between the dam and Auburn (river mile 32) there are two major tributaries, Soos Creek and Newaukum Creek, as well as several smaller tributary streams. This section of the Green River is characterized by suburban development and rural land. Several important environmental and cultural resources, such as the Green River Gorge and Flaming Geyser State Park, can be found in the middle reach of the Green River. As the river continues toward Puget Sound, urban areas line the river. The Green River becomes the Duwamish River at the former confluence with the Black River at Tukwila (near river mile 11).
The lower Green River watershed, from the City of Auburn to the downstream boundary of the planning area (river mile 6.5), is characterized by urban development. There are three tributaries in this reach of the Green River: Springbrook Creek, Mullen Slough, and Mill Creek. Along the lower Green River, the river is mostly contained by a levee or revetment on at least one bank. This area is significantly more developed than the upper and middle watersheds with residential and commercial properties.
The planning area ends on the Duwamish River at river mile 6.5 near Cecil Moses Memorial Park on the left bank and North Wind’s Weir on the right bank. The remainder of the Duwamish River/Waterway, from the weir to the mouth at Elliott Bay in Seattle, is included in the Central Puget Sound GRP. The planning area is within the Duwamish-Green Watershed or Water Resource Inventory Area (WRIA) 9.
Developed Areas
Upstream to downstream Green River/Duwamish passes by or through the towns and cities of Covington, Maple Valley, Black Diamond, Enumclaw, Algona, Federal Way, Auburn, Kent, SeaTac, Tukwila, and Renton. The planning area is fully within King County.
Tribes of the Green river Duwamish GRP Planning Area
The Green River/Duwamish GRP planning area is within the usual and accustomed territories of a number of American Indian Tribes. The Indian reservation of the Muckleshoot Indian Tribe is located near the city of Auburn, within and south of the Green River/Duwamish GRP planning area.
Federally recognized Tribes with access to the resources of the Green River/Duwamish GRP planning area may include:
- Lummi Nation
- Muckleshoot Indian Tribe
- Nooksack Indian Tribe
- Port Gamble S’Klallam
- Puyallup Tribe of Indians
- Sauk-Suiattle Indian Tribe
- Snoqualmie Tribe
- Squaxin Island Tribe
- Stillaguamish Tribe of Indians
- Suquamish Tribe
- Swinomish Indian Tribal Community
- Tulalip Tribes
- Upper Skagit Tribe
- Confederated Tribes and Bands of the Yakama Nation
Tribes can fill many roles during an oil spill response including full participation in Unified Command, providing resource specialists in the Environmental Unit, monitoring on-scene operations, and more. Information regarding tribal participation in a response is available on the Northwest Area Committee/Region 10 Regional Response Team website. Contact information for the tribes in this planning area can be found in the Resources at Risk section and on the Spill Response Contact Sheet of this GRP.
Physical Features
Despite seemingly contiguous sections presently, the reason for the Green River/Duwamish having two separate names is due to its pre-industrialized past. Prior to 1906, the Duwamish River was created by the confluence of the Green, White, and Black Rivers. The Green and White Rivers met upstream, and their combined discharge joined the Black River at what is now Tukwila. It was at this confluence that the three rivers’ output created the separately defined entity of the Duwamish River. The name “Duwamish” is derived from the Native American Lushootseed language, meaning “People of the Inside.”, a reference to that Tribe’s settlements along the river.
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Prior to the construction of the Hanson Dam, the Green River was subject to frequent flooding. During a flood in 1906, a debris jam redirected the White River away from the Green and into the Puyallup River out to Commencement Bay in Tacoma. After the 1906 flood, the White River’s course was altered permanently. Ten years later, the opening of the Lake Washington Ship Canal dropped the level of Lake Washington, the source of the Black River by 8.8 feet. The Black River subsequently dried up and its remaining stream bed/marshland now carries drainage and runoff. As a result, the confluence of rivers that once made up the Duwamish disappeared, melding it as a singular river with the Green. The naming designations, however, did not change. The Duwamish and the Green are now divided based upon the site of the historical confluence with the Black River, despite their the river’s single-thread from its headwaters to Puget Sound.
In addition to the upstream alterations, manmade interventions to the river’s path altered the landscape around the mouth of the Duwamish. Starting in 1913, the nine-mile, shallow and meandering Duwamish River was dredged and excavated into a five-mile engineered waterway. This also resulted in the creation of Harbor Island, which remains as the dominant feature of the Duwamish Waterway mouth and the epicenter for the Port of Seattle’s maritime shipping operations. Prior to these changes, the Duwamish Estuary had around 4,000 acres of tidal marshes and intertidal mudflats. This habitat has since disappeared. Almost all the estuarine mudflats, marshes, and forested riparian swamps in the area have been filled and replaced with commercial and industrial developments, with only patchy, small areas of restored habitat.
Geology
The Green/Duwamish watershed is found in the Puget Lowland, a geologic region formed by tectonic, volcanic, and glacial action. Like other rivers draining into Puget Sound, the Green River progresses from rocky alpine headwaters, to confined mountain valleys, into wide low gradient floodplains as the river descends to Puget Sound.
Between Flaming Geyser State Park and Kanaskat-Palmer State Park is the rocky corridor of the Green River Gorge. The 12-mile gorge has some of the most extensive and untouched pre-ice age sedimentary rock in the Puget Lowland. Near the State Route 169 bridge, the gorge walls are more than 450 feet high. Further upstream, the bluffs lining the river rise greater than 700 feet.
Cultural Features
People lived all along the Duwamish/Green River since time immemorial. Native people have harvested fish, hunted and forged throughout the watershed. Native people used western red cedar and other trees to make longhouses, dugout canoes, tools, clothing, and other items. Along the Green River shoreline, archaeological evidence of human occupancy can be found. A major settlement surrounding the confluence of the Black and Green Rivers was called “Inside Place,” from which the Duwamish peoples’ name originated.
In 1969, the Washington State Legislature created the Green River Gorge Conservation Area to preserve the last river-cut canyon in Western Washington that had yet to be dammed. The area is protected and available for the recreational uses of hikers, geologists, fishers, kayakers and canoeists, picnickers and swimmers, and those seeking the solitude offered by this unique area (RCW 70A.05.695).
Shoreline Description
Sediment varies throughout the watershed and includes cobbles, gravel, sand, clay, and silt. Exposed bedrock, primarily sandstone, is common in the upstream end of the planning area. In the Green River Valley, the river has meandered since the glacial retreat, depositing alluvial sediment in its floodplain. In the lower watershed, the river bottom is muddy.
Dams
The Howard A. Hanson Dam is an earthen embankment dam near the headwaters of the Green River, operated by the U.S. Army Corps of Engineers beginning in 1961. The base of the Hanson Dam is 960 feet wide and sits within Eagle Gorge. The earthen embankment structure of the Hanson Dam is 675 feet long and 235 feet high. The Hanson Dam Reservoir is seven miles long and has a capacity of 106,000 acre/ft. The primary purpose of the dam is to reduce flood risk and enhance fisheries in the Green River watershed.
Three miles downstream of the Hanson Dam is the Tacoma Headworks Diversion Dam near river mile 61. The Headworks Dam diverts surface water from the river into a treatment facility to supplies the City of Tacoma drinking water. Tacoma Water supplies approximately 50 million gallons of drinking water per day to over 300,000 people in Pierce and south King counties.
Superfund Sites & Other Historic Pollution Sites
Superfund sites in the Green River/Duwamish planning area include the Seattle Municipal Landfill in Kent (at river mile 20). Just downstream of the planning area (beginning around river mile 5) to the Puget Sound, the entire Duwamish Waterway is a superfund site.
Socio-economic Features
Large Scale Restoration Sites
Several response strategies included in this GRP were created to protect habitat restoration sites in the planning area. There locations include Codiga Park in Tukwila, Chinook Wind in Tukwila, and the Downey Farmstead Restoration Project in Kent.
Fishing & Sustenance
Several species of fish are found in the Green/Duwamish River including Chinook salmon, chum salmon, coho salmon, pink salmon, steelhead, cutthroat trout, and bull trout. Salmon hatcheries on the Green River produce millions of Chinook salmon, coho salmon, and steelhead every year to enhance fishing opportunities and help conserve fish for the future. Salmon of wild origins can be found in the watershed year-round in various parts of their life cycle. The Green River is recognized as one of the top steelhead rivers in Washington. Anglers will fish from the shoreline into deep holes where the salmon and steelhead rest as they make their way upstream to spawn. Salmon fisheries typically occur from late summer to early winter.
Recreation & Tourism
The Green River Gorge, which cuts through Flaming Geyser State Park, is popular for recreational users. The Green River is one of the top whitewater rivers in Washington, with Class III and IV rapids in the Green River Gorge. Rafters, kayakers, and other whitewater boaters use the river October to May when flow levels are strong.
In summer months, the Green River is a popular destination for tubers who leisurely float down the river on hot summer days. Tubers put in at Flaming Geyser State Park, float downstream, and get off the river at Whitney Bridge Park or the Porter Levee Natural Area near the Highway 18 bridge.
The shorelines of the Green/Duwamish River are a popular destination for walkers, cyclers, hikers, and horseback riders. King County’s Green River Natural Area offers 7.4 miles of trails, several ending at the bank of the Green River. The 19-mile Green River Trail follows the river from the industrial area near the Duwamish Waterway in Tukwila to the North Green River Park in south Kent near Auburn.
Hydrology
Howard A. Hanson Dam is instrumental in controlling the hydrology of the watershed. The Hanson Dam manages the flow of water down to sea level from an elevation of 1,206 feet. In the winter, the dam’s reservoir is left nearly empty and the river flows through a gate-controlled tunnel on the earthen dam. After storm events, water is held in the reservoir and slowly released in quantities that stay within the capacity of the downstream channel to prevent flooding. During times of low flow in the summer and fall, the U.S. Army Corps of Engineers, who operate the dam, will release water to augment instream flow for fish.
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Glacial meltwater and precipitation influence the flow of the Green River. Snowfall near Stampede Pass can be substantial, ranging from 300 to 600 inches annually. Rainfall in the mountainous regions of the planning area can exceed 60 inches annually. In the lowland areas near Puget Sound, annual rainfall averages around 37 inches.
In the lower watershed, urban development has substantially increased stormwater runoff from small tributary streams. This causes larger and more frequent peak flows during large rain events.
The United States Geological Survey (USGS) provides current streamflow data and the National Oceanic and Atmospheric Administration (NOAA) provides advanced hydrologic predictions. Stations are located on the Green River below the Howard A. Hanson Dam, at the purification plant near Palmer, below Crisp Creek near Black Diamond, in Auburn, three sites in Kent, and in Tukwila.
Climate and Winds
The Green River/Duwamish GRP planning area falls within the Central Puget Sound region of Washington State. Average precipitation ranges from 30-35 inches per year in the coastal areas to 70 inches in the mountains (WA Dept. of Ecology). The average high temperatures in the summer reach the mid to upper 70s with an average low in the mid-50s. In the winter, the average high is in the upper 40s, and the low is in the mid to upper 30s in the Kent/Auburn area. Temperatures drop and snowfall increases in the upper watershed.
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The prevailing wind direction is south or southwest during the wet season and northwest in the summer throughout the planning area. In the lower planning area of the Puget Lowland, the average wind velocity is less than 10 miles per hour. The strongest winds occur during the late fall and winter. In the Green River Valley, velocities can reach 40 to 50 miles per hour during winter extreme weather events.
Tides and Currents
Tidal influences are observed upstream to about the mouth of the Black River in the city of Tukwila. Puget Sound’s tides are mixed semi-diurnal, with two daily high tides and two low tides of varying heights per day. In the lower Green River/Duwamish the river’s waterline can move several feet up and down the width of the shoreline over a tidal cycle. Tidal predictions for Seattle are available from NOAA.
Risk Assessment
The Green River/Duwamish area is plentiful in natural, cultural, and economic resources, all at risk of injury from oil spills. Potential oil spill risks include, but aren’t limited to: road transportation, rail transportation, oil pipelines, aircraft, recreational boating, and other oil spill risks. This section briefly discusses these risks and how they could impact the Green River/Duwamish GRP planning area.
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Non-Floating Oils: Both refined petroleum products and crude oils are transported in bulk within this planning area. Crude oil contains a mix of hydrocarbons with a wide range of properties, while a refined product is a single type of oil, such as diesel or gasoline. Depending on the oil and the characteristics of the water the oil is spilled into, some of the oil transported in this planning area may not float.
Different oils will behave differently when spilled to water. Some heavy oils will sink immediately, some oil suspends in the water column, and lighter oils may remain on the surface and evaporate within hours. Over time, oil that initially floats can weather and mix with sediment, causing it to submerge or sink. Non-floating oils pose a specific risk to the environment because they can harm underwater or bottom-dwelling species that would otherwise be unaffected during an oil spill that remained floating on the water’s surface.
Traditional response strategies, including the booming strategies in this GRP, are designed for floating oil. However, there are steps we can take to plan for and respond to a non-floating oil spill. Non-Floating Oil Response Options and Considerations provides an overview of areas where non-floating oil might accumulate if spilled within this planning area, along with information on specific tactics that may be effective during a response. More response options recommended for finding and recovering oil below the water’s surface can be found in the Non-Floating Oil Spill Response Tool (NWACP Section 9412).
Facilities: The planning area contains two Class 1 regulated bulk petroleum facilities, the Olympic Pipeline Renton Products Terminal and the Phillips 66 Renton Terminal. Both facilities are tank farms, which house millions of gallons of refined oil in clusters of storage tanks. These regulated petroleum facilities, and the products they handle, can be viewed on the Ecology Spills Map.
Rail Transportation: Rail companies transport oil through this planning area using both unit trains and manifest trains. Unit trains include up to four locomotives, buffer cars, and 118 loaded tank cars transporting oil in 714-barrel (29,998 gallon) capacity USDOT-approved tank cars. Manifest trains include up to four locomotives, a mix of non-oil merchandise cars, and one or more 714-barrel (29,998 gallon) capacity USDOT-approved tank cars carrying refined oil products, such as diesel, lubrication oil, or gasoline. These trains may include emptied tank cars, each with residual quantities of up to 1,800 gallons of crude oil or petroleum products. Every train locomotive typically holds a few hundred gallons of engine lubrication oil, plus saddle tanks that each have an approximate capacity of 5,000 gallons of diesel fuel. Manifest trains may also transport biological oils and non-petroleum chemicals.
Unit trains carrying crude currently operate on specific routes. Unit trains carrying crude from the Bakken Formation in North Dakota enter Washington State near Spokane, continue along the Columbia River to Vancouver, and then head north along I-5 to Canada. Each loaded tanker car typically contains 29,000 gallons of crude oil or other petroleum products. Unit trains carry 100 or more of these tanker cars of crude, plus a buffer car of sand and the locomotives. Each full unit train poses a spill risk of nearly 3 million gallons of crude oil plus 10,000 gallons of diesel fuel. Tanker cars of crude can also be transported in smaller numbers, mixed alongside boxcars and tankers of other products. In the Green River/Duwamish planning area, BNSF and Union Pacific operate railways running near the Green River in Auburn and Tukwila.
In addition, BNSF operates an east-west railway that runs parallel to the Green River over the Cascade Mountain Range. This line goes from Auburn through Stampede Pass to Yakima. Due to the steep grade of the pass, most of the train cars using this route are empty. Even empty, tanker cars can contain residual oils in the tens or hundreds of gallons. The residual oil in empty unit trains, which consist of 100 or more oil tanker cars, can present a substantial risk to the watershed.
Just outside the planning area, BNSF operates a rail yard in southern Auburn south of Highway 18 and east of Highway 167. The yard is located on the historic bed of the White River, which is now located further south and empties into the Puyallup. Although the surface water has relocated, there is still an underground flow between the subterranean aquifers of the White and Green Rivers. Therefore, even though it is in a different watershed, oil spilled at this rail yard could eventually appear on the Green River.
Commuter trains using diesel locomotives run on BNSF tracks between Tacoma and Seattle, including Amtrak and the Sounder. The Link Light Rail line between SeaTac airport and Lynnwood is electric and therefore not a significant potential spill source.
Oil Pipelines: There is one refined petroleum pipeline in the planning area, Olympic Pipeline. If this pipeline were to leak or rupture, the impact to natural, cultural, and economic resources could be significant. Olympic Pipeline consists of over 400 miles of petroleum product pipeline. The pipelines extend from refineries in Northwest Washington and run parallel to Puget Sound and Interstate-5 to Portland, Oregon. The pipeline transports various grades of unleaded gasoline, aviation turbine fuel (kerosene), and diesel fuel. It delivers fuel to Harbor Island in Seattle, Seattle-Tacoma International Airport, Renton, Tacoma, Vancouver Washington, and Portland Oregon. Two pipeline terminals are located in the planning area. BP Pipelines North America owns and operates Olympic Pipeline.
Road Systems: Vehicle traffic on roadways pose an oil spill risk in areas where they run adjacent or cross the Green River or its tributaries. Major roadways in the planning area include Interstate 5, Highway 164, and Highway 18. A vehicle spill from a bridge or roadway can cause fuel or oil to flow from hardened surfaces into the Green River. Commercial trucks can contain hundreds to thousands of gallons of fuel and oil, especially fully loaded tank trucks, and may carry almost any kind of cargo, including hazardous waste or other materials that might injure sensitive resources if spilled. Smaller vehicle accidents pose a risk as well, a risk commensurate to the volume of fuel and oil they carry.
Aircraft: Several airports are located within the Green River/Duwamish planning area including the Seattle-Tacoma International Airport, Renton Municipal Airport, and Auburn Municipal Airport. Landing strips at these airports are used for recreational, commercial, and transit purposes. With airports in the area, the potential exists for aircraft failures during inbound or outbound flights that could result in a spill with a release of jet fuel to the Green/Duwamish River and its tributaries.
Recreational Boating: Accidents involving recreational watercraft on the Green/Duwamish could result in spills between a few gallons to several dozen gallons of fuel oil. Accidents could include a vessel grounding, fire, sinking, or explosion. Bilge discharges and refueling operations could also occur (and are likely most common) and have the potential to impact sensitive resources on the river. Most motorized boat traffic ends downstream of the planning area, but the Green River is considered a navigable waterway up to the Highway 516 Bridge in Kent (USCG). Recreational vessels in the remainder of the watershed tend to be hand-launched rafts, canoes, or kayaks.
Other Spill Risks: Other potential oil spill risks in the area include road run-off during rain events, onshore or near shore construction activities where heavy equipment is being operated, and the migration of spilled oil through soil on lands adjacent to the river or along creek/stream banks.
Resources at Risk
This section provides a summary of natural, cultural, and economic resources at risk in the planning area, including those resources at risk from oils with the potential to sink or submerge. It provides general information on habitat, fish, and wildlife resources, and locations in the area where sensitive natural resource concerns have been identified. It offers a summary of cultural resources that include fundamental procedures for the discovery of cultural artifacts and human skeletal remains. General information about flight restrictions, wildlife deterrence, and oiled wildlife can be found near the end of this section. A list of economic resources in the area is downloadable from the table of contents on this webpage.
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This section is purposely broad in scope and should not be considered comprehensive. Some of the sensitive resources described in this section cannot be addressed in Response Strategies and Priorities because it is not possible to conduct effective response activities in these locations. Additional information from private organizations or federal, state, tribal, and local government agencies should also be sought during spills. This material is presented with enough detail to give general information about the area during the first phase of a spill response. During an actual incident, more information about resources at risk will be available from the Environmental Unit in the Planning Section.
Note: specific resource concerns related to areas that already have designated protection strategies may be found in the “Resources At Risk” column of the matrix describing the individual strategies.
The information provided in this section can be used in:
- Assisting the Environmental Unit (EU) and Operations in developing ad hoc response strategies.
- Providing resource-at-risk “context” to responders, clean-up workers, and others during the initial phase of a spill response in the GRP area.
- Briefing responders and incident command staff that may be unfamiliar with sensitive resource concerns in the GRP area.
- Providing background information for personnel involved in media presentations and public outreach during a spill incident.
- Providing information on benthic and water column species or cultural resources present to assist in planning for oils with the potential to sink or submerge.
Natural Resources at Risk – Summary
This area contains a wide variety of aquatic, riparian, and upland habitats. These habitats support many of Washington’s salmonid species as well as a complex diversity of other wildlife. In addition to those species directly at risk to oil spills, other species that are unlikely to become directly oiled during a spill incident (due to their life histories and/or behaviors) may be disturbed by other operations such as cleanup, reconnaissance, or fire suppression activities. Some bird species are resident throughout the year, but many others seasonally migrate outside of the area.
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Several of the species found in this area have been classified under the Federal Endangered Species Act or by the Washington State Fish and Wildlife commission.
Classification types are:
- Federal Endangered (FE)
- Federal Threatened (FT)
- Federal Candidate (FC)
- State Endangered (SE)
- State Threatened (ST)
- State Sensitive (SS)
Federal and State Threatened, Endangered, and Sensitive species that may occur within this area, at some time of the year, include:
Birds:
- marbled murrelet [FT/SE]
- yellow billed cuckoo [FT/SE]
Mammals:
- wolverine [FT]
Fish:
- bull trout [FT]
- chinook salmon (Puget Sound) [FT]
- steelhead (Puget Sound) [FT]
Amphibians/Reptiles:
- Oregon spotted frog [FT/SE]
Insects:
- Monarch butterfly [FC]
- Taylor’s checkerspot butterfly [FE/SE]
Critical habitats are the specific areas, occupied by an endangered or threatened species at the time it was listed, that contain the physical or biological features that are essential to the conservation of that species – and that may need special management or protection. Critical habitat may also include areas that were not occupied by the species at the time of listing but are essential to its conservation.
The following species have federally designated critical habitats within this area:
- bull trout
- chinook salmon (Puget Sound)
- steelhead (Puget Sound)
General Resource Concerns
Habitats:
- The Duwamish River estuary provides habitat for salmonids from the Duwamish/Green River systems. The tidally influenced areas serve as a transitional area between the river and Elliot Bay. Several habitat restoration areas are in this reach.
- Wetlands in this region are freshwater and range from seasonal open marshes to forested swamps along rivers and streams. All wetland types support a diverse array of amphibian, bird, insect, fish, and wildlife species.
- The rivers and streams throughout this region provide spawning and rearing habitat for various salmonid species. The benthic habitats in streams and rivers may include freshwater mussels and immature lamprey. The associated riparian scrub and woodlands play a crucial role in supporting wildlife and a large diversity and abundance of passerine bird species as breeding, migrating, and overwintering habitat.
- Side channels and stream mouths are concentration areas for fish and provide feeding and resting areas for a variety of birds.
- Steep forested hill slopes in developed areas along river valley provide wildlife habitat and migration corridors.
- Lowland lakes serve as foraging areas for wintering waterfowl concentrations. Western grebes, mergansers, cormorants, coots and Canada geese are the most numerous species. These areas also support the breeding activities of freshwater resident species such as mallards, pintail, etc.
- Subsurface Habitats
- Fine sediments (mud/silt/sand) – Associated with slow/still water flows. May have aquatic vegetation present.
- Animals associated with these areas tend to be: cold or warm water fishes; birds (dabbling ducks); semi-aquatic mammals (muskrat, beaver, etc.); shellfish (freshwater clams); amphibians and reptiles (frogs, newts, salamanders, turtles, etc.); insects caddis flies, mayflies, dragonflies, and stoneflies). Many other animals also utilize these areas for foraging.
- Coarse sediments (gravel/cobble) – Associated with moderate water flow. May have aquatic vegetation present.
- Animals associated with these areas tend to be: cold or warm water fishes; birds (dippers, harlequin ducks); semi-aquatic mammals (muskrat, beaver, etc.); shellfish (freshwater mussels, crayfish); amphibians and reptiles (tailed frogs, torrent salamanders; insects caddis flies, stoneflies). Many other animals also utilize these areas for foraging.
- Bedrock – Associated with fast water with little or no deposition of loose bed materials. Aquatic vegetation typically not present.
- Animals associated with these areas tend to be mostly cold-water fishes, birds (dippers, harlequin ducks), and amphibians (torrent salamanders).
Fish:
- All northwest salmonid species, including bull trout [FT], chinook [FT], and steelhead trout [FT] are present and spawning in this river system. Juvenile salmonids use shallow nearshore areas extensively for feeding and rearing.
- Resident fish are present year-round and include various species such as resident cutthroat and rainbow trout, stickleback, sculpin, sucker, and lamprey.
Wildlife:
- Significant waterfowl concentrations are present along the lower Green River and within associated wetlands below the Flaming Geyser Park. Harlequin duck nesting areas located throughout drainage above this park.
- Sensitive nesting species in the region include raptors (bald eagles, osprey, northern goshawks, and peregrine falcons) and great blue herons.
- Resident and migratory songbirds heavily utilize riparian habitats year-round and are susceptible both to oil and to response activities that disturb riparian vegetation
- Winter elk range occur in the upper reaches of the Green River. King county elk habitat includes resident and migratory elk.
- Other small mammals common to the region include semi-aquatic species such as beaver, muskrat, river otter, and raccoon. These species are vulnerable to contact with spilled oil because of their habitat preferences.
- Harbor seals and sea lions are common throughout the Duwamish waterway and the lower Green River
Specific Geographic Areas of Concern
Areas of concern include shorelines with natural riparian vegetation, wetlands, stream mouths, and shallow backwater areas. Public parks, private lands, and recreational areas also surround the river.
The number that precedes the area name in the list (below) corresponds to the numbered area on the map (Figures 1 or 2).
- Black River Riparian Forest and Wetland/Fort Dent Park: Urban deciduous riparian forest and wetlands located at mouth of the Black River. Great blue heron colony on site. Waterfowl use area. Bald eagle nesting and foraging area.
- Green River Natural Resource Area: ~300 acres of stormwater retention and managed wetland. Waterfowl concentration area. Salmonid rearing area. Van Dorn’s and Valley Floor Parks are in the same general vicinity.
- North Green River Park: Riparian vegetation and wetland habitat. Waterfowl concentration area.
- East Green River Park: Riparian vegetation and wetland habitat. Waterfowl concentration area. Flooded fields provide forage habitat for large numbers of dabbling ducks.
- Green River Natural Area: ~920-acre area, with ~6 miles of shoreline. Deciduous riparian forest, wetlands, and meadows located along south bank of river.
- Black Diamond Natural Area: ~650 acres. Deciduous riparian forest, wetlands, and meadows located along both riverbanks.
- Howard Hanson Reservoir: Freshwater lake and wetland habitats. Bald eagle and osprey nesting. Harlequin duck and common loon breeding area. Salmonid presence including Chinook, chum, and coho salmon as well as bull, cutthroat and steelhead trout. Elk winter concentration area.
- Green River: Riverine and isolated wetland habitats. Bald eagle and osprey nesting. Harlequin duck and common loon breeding area. Salmonid presence including Chinook, chum, and coho salmon, as well as bull, cutthroat, rainbow and steelhead trout. Elk winter concentration area.
Cultural Resources at Risk – Summary
Culturally significant resources are present within the planning area. Information regarding the type and location of cultural resources is maintained by the Washington Department of Archeology and Historic Preservation (WDAHP). This sensitive information is made available to the Washington Department of Ecology for oil spill preparedness and response planning. The Tribal Historic Preservation Offices (THPOs) or Cultural Resource Departments of local tribes (see Table 6‑1) may also be able to provide information on cultural resources at risk in the area and should be contacted, along with WDAHP, through normal trustee notification processes when significant oil spills, or smaller spills above reportable thresholds, occur in the area.
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During a spill response, after the Unified Command is established, information related to specific archeological concerns will be coordinated through the Environmental Unit. To ensure that tactical response strategies do not inadvertently harm culturally sensitive sites, WDAHP should be consulted before disturbing any soil or sediment during a response action, including submerged soils or sediments. WDAHP and/or the Tribal governments may assign a person or provide a list of professional archeologists that can be contracted, to monitor response activities and cleanup operations for the protection of cultural resources at risk. Due to the sensitive nature of such information, details regarding the location and type of cultural resources present are not included in this document.
Table 6-1: GRD-GRP Cultural Resource Contacts
| Contact | Phone | |
| Washington Department of Archeology and Historic Preservation (WDAHP) | 360- 586-3080 | Rob.Whitlam@dahp.wa.gov |
| Lummi Nation, THPO | 360-312-2257 | lenat@lummi-nsn.gov |
| Muckleshoot Indian Tribe, THPO | 253-876-3272 | laura.murphy@muckleshoot.nsn.us |
| Nooksack Indian Tribe, THPO | 360-592-5176 | george.swanasetjr@nooksack-nsn.gov |
| Port Gamble S’Klallam, THPO | 360-297-9629 | mives@pgst.nsn.us |
| Puyallup Tribe of Indians, THPO | 253-573-7965 | Brandon.Reynon@PuyallupTribe-nsn.gov |
| Sauk-Suiattle Indian Tribe, THPO | 360-436-0333 | mporter@sauk-suiattle.com |
| Snoqualmie Indian Tribe, Cultural Resources | 425-888-6551 | Steve@snoqualmietribe.us |
| Squaxin Island Tribe, THPO | 360-432-3850 | rfoster@squaxin.us |
| Stillaguamish Tribe of Indians, THPO | 360-652-3687 | KLyste@stillaguamish.com |
| Suquamish Tribe, THPO | 360-394-8529 | dlewarch@suquamish.nsn.us |
| Swinomish Indian Tribal Community, THPO | 360-466-7352 | jjefferson@swinomish.nsn.us |
| Tulalip Tribes, Cultural Resources | 425-239-0182 | ryoung@tulaliptribes-nsn.gov |
| Upper Skagit Tribe, Cultural Resources | 360-982-8218 | ScottS@UPPERSKAGIT.com |
| Confederated Tribes and Bands of the Yakama Nation, THPO | 509-865-5121 | kate_valdez@yakama.com |
Discovery of Human Skeletal Remains
The finding of human skeletal remains will be reported to the county medical examiner/coroner and local law enforcement in the most expeditious manner possible. The remains will not be touched, moved, or further disturbed. The county medical examiner/coroner will assume jurisdiction over the human skeletal remains and make a determination of whether those remains are forensic or non-forensic. If the county medical examiner/coroner determines the remains are non-forensic, then they will report that finding to the Department of Archaeology and Historic Preservation (DAHP) who will then take jurisdiction over the remains. The DAHP will notify any appropriate cemeteries and all affected tribes of the find. The State Physical Anthropologist will make a determination of whether the remains are Indian or Non-Indian and report that finding to any appropriate cemeteries and the affected tribes. The DAHP will then handle all consultation with the affected parties as to the future preservation, excavation, and disposition of the remains.
Any human remains, burial sites, or burial-related materials that are discovered during a spill response must be treated with respect at all times (photographing human remains is prohibited to all except the appropriate authorities). Refer to National Historic Preservation Act Compliance Guidelines (NWACP Section 9403) during an emergency response.
Procedures for the Discovery of Cultural Resources
If any person monitoring work activities or involved in spill response believes that they have encountered cultural resources, all workers must stop immediately and notify the Unified Command and Cultural Resource Specialist. The area of work stoppage must be adequate to provide for the security, protection, and integrity of the material or artifact(s) discovered.
Prehistoric Cultural Resources (May include, but are not limited to, any of the following items):
- Lithic debitage (stone chips and other tool-making byproducts)
- Flaked or ground stone tools
- Exotic rock, minerals, or quarries
- Concentrations of organically stained sediments, charcoal, or ash
- Fire-modified rock
- Rock alignments or rock structures
- Bone (burned, modified, or in association with other bone, artifacts, or features)
- Shell or shell fragments
- Petroglyphs and pictographs
- Fish weirs, fish traps, and prehistoric watercraft
- Culturally modified trees
- Physical locations or features (traditional cultural properties)
- Submerged villages sites or artifacts
Historic cultural material (May include any of the following items over 50 years old):
- Bottles, or other glass
- Cans
- Ceramics
- Milled wood, brick, concrete, metal, or other building material
- Trash dumps
- Homesteads, building remains
- Logging, mining, or railroad features
- Piers, wharves, docks, bridges, dams, or shipwrecks
- Shipwrecks or other submerged historical objects
Economic Resources at Risk Summary
Socio-economic sensitive resources are facilities or locations that rely on a body of water to be economically viable. Because of their location, they could be severely impacted if an oil spill were to occur. Economically sensitive resources are separated into three categories: critical infrastructure, water dependent commercial areas, and water dependent recreation areas. Another section lists economic resources for this planning area.
General Information
Flight restriction zones
The Environmental Unit (Planning Section) may recommend flight restriction zones to minimize disturbance or injury to wildlife during an oil spill. Pilots/operators can decrease the risk of aircraft/bird collisions, prevent the accidental driving of wildlife into oiled areas, and minimize abandonment of nests by keeping a safe distance and altitude from these identified sensitive areas.
The Air Operations Branch (Operations Section) will manage all aircraft operations related to a response and will coordinate the establishment of any Flight Restriction Zones as appropriate. Environmental Unit staff will work with the Air Operations Branch Director to resolve any conflicts that arise between flight activities and sensitive resources.
In addition to restrictions associated with wildlife, Tribal authorities may also request notification when overflights are likely to affect culturally sensitive areas within reservations. See Oil Spill Best Management Practices (NWACP Section 9301) for more information on the use of aircraft and helicopters in open water and shoreline responses.
Wildlife Deterrence
The Wildlife Deterrence Unit within the Wildlife Branch (Operations Section) manages wildlife deterrence operations. These are actions intended to minimize injuries to wildlife by keeping animals away from the oil and cleanup operations. Deterrence activities may include using acoustic or visual deterrent devices, boats, aircraft or other tools. The Wildlife Branch works with state and federal agencies, and the Environmental Unit (Planning Section), to develop deterrence plans as appropriate.
For more information see the Northwest Wildlife Response Plan (NWACP Section 9310) and Northwest Area Wildlife Deterrence Resources (NWACP Section 9311).
Oiled Wildlife
Capturing oiled wildlife may be hazardous to both personnel and the affected animals. Incident personnel should not try to approach or capture oiled wildlife but should report any observations of oiled wildlife to the Wildlife Branch (Operations Section).
For more information see the Northwest Wildlife Response Plan (NWACP Section 9310).
Wildlife Refuges and Wilderness Areas
There are no federally designated wilderness areas or wildlife refuges present in this GRP region.
Aquatic Invasive Species
The waters of this region may contain aquatic invasive species (AIS) – species of plants and/or animals that are not native to an area and that can be harmful to an area’s ecosystem. If so, preventative actions may be required to prevent the spread of these species as a result of spill response activities and the Environmental Unit is able to recommend operational techniques and strategies to assist with this issue.