Lake Washington GRP
- Open for full review: 2021
- Last full updated: 2014
- Public Comment: GRPs@ecy.wa.gov
- Contact: Sabrina Floudaras
Table of Contents
This section provides a description of the area’s physical features, hydrology, climate and winds, and includes an overview of oil spill risks in the Lake Washington area. The area covered by this plan includes Lake Washington, lower portions of the Cedar and Sammamish Rivers, and downstream areas of Coal Creek, Juanita Creek, Kelsey Creek, Lyon Creek, May Creek, McAleer
Creek, Ravenna Creek, Taylor Creek, Thornton Creek, and Yesler Creek. Lake Washington includes Andrews Bay, Fairweather Bay, Juanita Bay, Meydenbauer Bay, Moss Bay, Pontiac Bay, Union Bay, Wolf Bay, Yarrow Bay, Cozy Cove, and shoreline areas of Mercer Island.
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The Lake Washington Geographic Response Plan (LKWA-GRP) encompasses an area of approximately 34 square miles and is bordered by the cities of Seattle (Montlake Bridge) to the west, Bellevue and Kirkland to the east, Kenmore to the north, and Renton to the south. The plan fully resides within the limits of King County. LKWA-GRP is bordered by the Central Puget Sound Geographic Response Plan to the west, and falls within the boundary of Water Resource Inventory Area 8 (WRIA-8, Cedar-Sammamish Watershed).
Lake Washington is a long, narrow, finger-shaped lake that’s approximately 22 miles long (north to south) and less than 2 miles wide near the middle (east to west). The lake has a surface area
of about 34 square miles, and an average depth of 108ft. The deepest part of the lake is reported to be 214ft. The water level in Lake Washington is regulated by the Hiram M. Chittenden Locks in Ballard (Seattle). Water levels in the lake vary within a couple of feet seasonally, but usually measure 16ft above mean sea level (Puget Sound) and 21ft above mean lower tide. The lake connects to Puget Sound (to the west) by way of the Lake Washington Ship Canal and the Chittenden Locks.
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The basin of Lake Washington is a deep glacial trough with steeply sloping sides, carved out by the last continental glacier that moved through the area during the late Pleistocene era. Water
and sediment accumulated in the lake as the glacier melted, and continues to accumulate today. The lake is surrounded by other north-south-oriented features that attest to the direction of ice flow; such as small inverted spoon shaped hills and larger hills. The modern shoreline of the lake is characterized by a 10-foot-high bench, embayments, gentle and steep slopes, and several peninsulas.
Lake Washington is the largest of the three major lakes in King County, and the second largest natural lake in the State of Washington. Most of the area around the lake is highly developed
and urban in nature. Two major influent streams feed the lake; the Cedar River on the south end near Renton, and the Sammamish River on the north side near Kenmore. The upper part of
the Cedar River is the source for much of the drinking water for the greater Seattle area and includes the Chester Morse Lake which serves as a water storage reservoir. Mercer Island lies in
the southern half of the lake and is separated from the southeastern shore by a relatively narrow and shallow channel.
Three floating bridges and two girder bridges carry vehicle traffic across Lake Washington today. The Evergreen Point Floating Bridge (SR-520) connects Seattle’s Montlake neighborhood
with Medina (located northwest of Bellevue). The Interstate 90 corridor across the lake uses two floating bridges to connect Seattle’s Mount Baker neighborhood with Mercer Island; the
Lacey V. Murrow Memorial Bridge carries east bound I-90 traffic to the island and the Homer M. Hadley Memorial Bridge carries west bound I-90 traffic from the island to Seattle. The East
Channel Bridge (girder bridges) allows east and westbound I-90 traffic to flow between Mercer Island and Bellevue.
Lake Washington has two major influent streams; the Cedar and Sammamish Rivers. The Cedar River at the southern end of the lake contributes about 57 percent of the annual runoff while
the Sammamish River on the north end contributes about 27 percent. Total annual flow is approximately 41 percent of the lake volume. Residence time is about 2.4 years. Lake Washington drains westward through Lake Union and the Ship Canal to Shilshole Bay in Puget Sound via the Chittenden Locks in Ballard. Lake Washington’s water level elevation varies by season, but is typically about 16ft above mean sea level (Puget Sound) and 21ft above mean lower tide.
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Tributaries to Lake Washington are essential contributors to its hydrologic budget. Rainfall plays a key role as well. About a quarter of the annual rainfall seeps or soaks into ground water and moves underground toward lakes and streams, or runs off land surfaces to lakes and streams. Lake Washington is located in Water Resource Inventory Area 8 (WRIA-8, Cedar- Sammamish).
Notable tributaries or sub-basins that drain to Lake Washington include:
- Bear Creek
- Cedar River
- Coal Creek
- Juanita Creek
- Kelsey Creek
- Lyon Creek
- May Creek
- McAleer Creek
- North Creek
- Ravenna Creek
- Sammamish River
- Swamp Creek
- Taylor Creek
- Thornton Creek
- Yesler Creek
Lake Stratification: Lake Washington undergoes annual stratification, with a strong thermocline developing about 39ft below the surface. As summer progresses, the temperature and density
difference between water at the surface and bottom becomes more distinct. Three water layers are formed; upper, middle, and bottom water layers. The upper layer (epilimnion) is characterized by warmer, less dense water. It’s the zone of light penetration where the most biological growth occurs. The middle layer (metalimnion or thermocline) is a narrow band of
water that’s colder than water in the upper layer but warmer than the lower waters beneath it. The middle layer helps prevent the mixing of upper and lower water layers. The bottom layer
(hypolimnion) holds the coldest water. Plant material either decays or sinks to the bottom and accumulates in this “stagnant” lower water layer.
During the winter the lake temperature remains above 39°F and substantial vertical mixing by wind action and convective overturn assures isothermal conditions. As ice melts in the Spring,
surface waters warm, then sink, and finally mix with deeper water. During summer the density of the water changes as its temperature changes. The water is most dense at 39°F, while above and below that temperature the water expands and becomes less dense. During the Fall, surface waters cool until they are as dense as the bottom waters and wind action mixes the lake so water temperature from surface to bottom are nearly the same.
Lake Washington Ship Canal and the Hiram M. Chittenden Locks: The ship canal is operated primarily as a navigation facility connecting Puget Sound with Lake Union and Lake Washington
via the Hiram M. Chittenden Locks. Under normal operations, surface waters in the canal are typically maintained at 20ft to 22ft above sea-level (Puget Sound, mean lower tide). The minimum elevation is maintained during the winter months to allow for annual maintenance on dock and wall structures, minimize wave and erosion damage during winter storms, and provide storage volume for high water inflow. Storage volume is also used to augment Lake Washington Ship Canal inflows for use in operating the Chittenden Locks, the saltwater return system, the smolt passage flume and the fish ladder facility at the locks. The Chittenden Locks and spillway dam regulate the elevation of Salmon Bay, Lake Union, Lake Washington and the Lake Washington Ship Canal. The locks and associated facilities serve three purposes:
- To maintain the water level of (fresh water) Lake Washington and Lake Union at 20
to 22 feet above sea level (Puget Sound).
- To prevent the mixing of sea water from Puget Sound with the fresh water of the
lakes (saltwater intrusion).
- Move boats to and from the water level of the lakes to the water level of Puget
The Chittenden Locks sit in the middle of Salmon Bay and are part of Seattle’s Lake Washington Ship Canal. They include a smaller 30ft x 150ft lock and a larger 80ft x 825ft lock. The Chittenden complex also includes a 235ft spillway with six gates to assist water-level control. A fish ladder is integrated into the locks for migration of anadromous fish (most notably salmon).
|Lake Washington Characteristics|
|Drainage Area (including Mercer Island)||357,760 Acres (559 Miles2)|
|Lake Area||21,500 Acres|
|Lake Volume||2,350,000 Acre-ft|
|Flushing Rate||0.43 per year|
|Depth of Epilimnion||39ft|
|Main Inflows||Cedar River (57%), Sammamish River (27%)|
|Main Outlet||Ship Canal to Puget Sound|
|Typical Period of Stratification||Late March to Early November|
Climate and Winds
Seattle’s climate is usually described as oceanic or temperate marine; winters are typically mild and wet while summers are usually warm and dry. Temperature extremes are moderated by
the adjacent Puget Sound, greater Pacific Ocean, and Lake Washington. The region is largely denied pacific storms by the Olympic Mountains and cold arctic air by the Cascade Range. Despite being on the margin of the rain shadow of the Olympic Mountains, the Seattle area has a reputation for frequent rain. Records show that Seattle is usually cloudy more than 200-days
per year, and partly cloudy more than 90-days annually.
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The area receives approximately 37.41 inches of rain a year and statistics show that the city is becoming wetter; the current annual rainfall average reflects an increase of 0.4 inches. Seattle
experiences moderate to heavy rain during the months of November, December, and January. The city receives roughly half of its annual rainfall (by volume) during these three months. In
late fall to early winter, atmospheric rivers known as “Pineapple Express” systems, strong frontal systems, and Pacific storms are common. Light rain and drizzle are the predominant forms of precipitation during the remainder of the year; for instance, on average, less than 1.6 inches of rain falls in July and August combined. Winds in the area are variable with the western portion of the lake being affected by marine winds from Puget Sound. Wind speeds often vary by season, with the highest winds generally occurring from November through January. Wind gusts can occasionally reach 50 mph or greater.
Seattle occasionally experiences extraordinary weather events. One such event occurred in December 2007 when sustained hurricane-force winds and widespread heavy rainfall associated with a strong “Pineapple Express” event occurred in the greater Puget Sound area and the western parts of Washington and Oregon. Precipitation totals exceeded 13.8 inches in some areas with winds reaching 130 mph along coastal Oregon. It was the second wettest weather event in Seattle’s recorded history with 5.1 inches of rain falling on the city in a 24-hour period.
Tides and Currents
Lake Washington is not impacted by tides, and no information on current flow in the lake is available (seasonal current flows or otherwise).
Lake Washington is plentiful in natural, cultural, and economic resources, all at risk of injury from oil spills. Potential risks to sensitive resources in the area include, but aren’t limited to, oil
pipelines, road transportation, vessel traffic, and aircraft. This section briefly discusses these
risks in the Lake Washington GRP area.
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Oil Pipelines: The Olympic Pipeline (OPL) poses an oil spill risk to Lake Washington. It transports thousands of gallons of refined petroleum products each year; mainly diesel and gasoline. The pipeline runs south from Seattle, around the southern end of the lake near Renton, north along the eastern side of the lake through Eastgate, and continues north through Kenmore and points beyond. The OPL crosses several rivers and tributary streams that directly or indirectly drain into Lake Washington, including the Cedar River, Honey Dew Creek, May Creek, Richards Creek, and the Sammamish River.
Road Transportation: Vehicle traffic on bridges or roadways over or near Lake Washington pose an oil spill risk. Commercial trucks can contain hundreds to thousands of gallons of fuel and oil, and almost any kind of hazardous material or waste. An accident involving a fully loaded tank truck on one of the lake bridges could result in a substantial oil spill. Smaller vehicle accidents pose a similar risk, commensurate to the volume of fuel and oil they carry. Spills from vehicles onto roadways along shore could cause fuel or oil to flow into the lake from harden surfaces or through storm water systems that drain directly or indirectly into Lake Washington.
Vessel Traffic: Incidents involving the grounding, sinking, collision or allision of commercial and recreational vessels on Lake Washington pose an oil spill risk. Potential exists for vessels on the lake to collide with each other or sink after hitting fixed structures (e.g. docks or bridges). Oil spill risks also include boat refueling and bilge/waste water pumping. Private and public marinas and docks on Lake Washington that refuel boats or recover waste products from them, or locations where boats are launched and recovered from the lake, might be considered potential spill source locations.
Aircraft: Lake Washington is home to Kenmore Air Harbor, a passenger seaplane service located at the north end of the lake in Kenmore. Renton’s Municipal Airport located near the south end of the lake includes Boeing’s Renton Ramp, Will Rogers Wiley Post Memorial Seaplane Base, Northwest Seaplanes, and Pro-Flight Aviation. Although oil spill risks to Lake Washington from these facilities are relatively small, it’s important to consider the potential for aircraft failures resulting in fuel releases to water. Float planes landing or flying over the lake might also pose an oil spill risk.
Resources at Risk
This section provides a summary of natural, cultural, and economic resources at risk in the Lake Washington area. It provides general information on habitat, fish, and wildlife resources, and
locations in the area where sensitive natural resource concerns exist. 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, hazing, and oiled wildlife can be found near the end of this section. A list of economic resources in the area is provided as an appendix.
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This section is purposely broad in scope and should not be considered comprehensive. Some of the sensitive resources provided in this chapter are listed because they could not be addressed
in Section 4 (Response Strategies and Priorities). Additional information from private organizations or federal, state, tribal, and local government agencies should also be sought during spills and considered.
The information provided in this chapter can be used in:
- Assisting the Environmental Unit (EU) and Operations in developing additional response strategies beyond those found in Section 4.
- 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.
Natural Resources at Risk – Summary
The Lake Washington basin includes a wide variety of aquatic, riparian, and upland habitats. The area provides habitat to all of Washington’s salmonid species and affords a variety of habitat to
many bird species as well. These varied habitats support a complex diversity of wildlife species, including large and small mammals; passerine birds, raptors, upland birds, and waterfowl; reptiles; and amphibians. Some species are resident throughout the year; others are migratory either within the sub basin or, in many cases, seasonally migrate outside the sub basin. Populations of certain species are fragile and their future presence in the sub basin will require improved information and decisive management actions. Many wildlife species found in the sub
basin are classified as threatened, endangered, sensitive, or of special concern under the federal Endangered Species Act or Washington State guidelines.
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Classification types are listed below, with the abbreviation of each type provided in the brackets (to the right of the classification):
- Federal Endangered (FE)
- Federal Threatened (FT)
- Federal Candidate (FC)
- Federal Species of Concern (FCo)
- State Endangered (SE)
- State Threatened (ST)
- State Candidate (SC)
- State Monitored (SM)
- State Sensitive (SS)
Sensitive species that may occur within this area, at some time of year, include the following federal and state listed species:
- Bald Eagle [FCo/SS]
- Common Loon [SS]
- Great Blue Heron [SM]
- Marble Murrelet [FT/ST]
- Peregrine Falcon [FCo/SS]
- Pileated Woodpecker [SC]
- No information
- Bull trout [FT/SC]
- Puget Sound Chinook Salmon [FT/SC]
- Puget Sound Coho Salmon [FCo]
- Puget Sound Steelhead [FT]
- River Lamprey [FCo/SC]
- Western Pond Turtle (aka Pacific Pond Turtle) [FCo/SE]
- Oregon Spotted Frog [FC/SE]
General Resource Concerns
- Brackish Sloughs and Backwater Channels provide feeding and resting areas for waterfowl and herons and are rearing areas for juvenile fish.
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- Human-made structures such as pilings, rock jetties or log rafts may be used as roosting or nesting areas for a variety of marine birds and raptors.
- Islands provide important nesting habitat for a variety of bird species, as well as habitat for a variety of mammals. Gravel bars provide spawning habitat for Chinook salmon.
- Riparian vegetation is heavily used by a variety of wildlife and may also improve nearshore fish habitat.
- River and Stream Mouths are concentration areas for anadromous fish and are feeding areas for a variety of marine birds.
- Wetlands in this region include freshwater areas such as the Mercer Slough with forested fresh water swamps and marshes along the edges and upper end of the estuary. All wetland types support a diverse array of bird, insect and fish and wildlife species.
Fish & Shellfish:
- Freshwater Shellfish (including Oregon Floaters and Western Floaters) have been documented in the vicinity of Mercer Slough and the Gene Coulon Memorial Beach Park.
- Salmonids including all Washington’s salmonid species for Chinook, Coho, Sockeye, and Steelhead occur in this region, with most spawning occurring in the Sammamish and Cedar River systems.
- Bald eagles [ST] and Great Blue Heron [SM]nests throughout the region and are present year-round.
- Peregrine Falcons [FCo/SS] and Osprey also nest and forage in this region.
- Migratory and Wintering Waterfowl – Large concentrations occur in the vicinity of Saint Edward State Park, Denny Park, Juanita Bay, and Union Bay.
- Marbled Murrelets [FT/ST]occur throughout the region and have been observed on Lake Washington.
- Western Pond Turtles [FCo/SE] and Oregon Spotted Frogs [FC/SE] are historically documented, particularly in the shallow bays and wetland complexes of Lake Washington.
Specific Geographic Areas of Concern – Overview
The lower sections of tributaries that drain to Lake Washington are usually sensitive. They provide good habitat for the rearing of juvenile salmonids and support concentrations of migratory and wintering birds. Upstream areas are home to a large variety of wildlife, including fish and waterfowl. They contain wetlands within heavily developed urban areas. Public parks, private lands, and recreational areas surround the lake. Specific areas of concern are listed below and depicted on the map in the next section. The number that precedes the area name in the list (below) directly relates to the numbered area on the map.
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- Andrew’s Bay: Marbled Murrelets, Bald Eagles, and Osprey.
- Coal Creek: Coho and Sockeye Salmon, Winter Steelhead, Resident Cutthroat Trout, and Western Brook Lamprey.
- Cozy Cove: Bald Eagles and Wetlands (associated with the lake or smaller tributary streams). Area is heavily developed as urban housing and industrial. Some of these have an open water component.
- Fairweather Bay: Bald Eagles.
- Fairweather Bay (Tributary to Bay): Coho Salmon
- Forbes Creek: Coho Salmon.
- Gene Coulon Park: Bald Eagles, Osprey, and Freshwater Mussels.
- Juanita Bay: Pacific Lamprey, Bald Eagles, Trumpeter Swans, and Waterfowl concentrations.
- Juanita Creek: Summer and Fall Chinook, Coho, and Sockeye Salmon.
- Kirkland Beach Park: Bald Eagles.
- Luther Burbank Park: Bald Eagles, Common Loon, and Wetlands (associated with the lake or smaller tributary streams). Area is heavily developed as urban housing and industrial. Some of these have an open water component.
- Lyon Creek: Coho and Sockeye Salmon.
- Matthews Beach Park: Great Blue Heron.
- May Creek (Confluence): Purple Martin, Osprey, Scrub-Shrub, Forested and Emergent Marsh Wetlands along May Creek and tributaries including Lake Boren.
- McAleer Creek: Western Brook Lamprey, Summer and Fall Run Chinook Salmon, Coho and Sockeye Salmon, and Resident Cutthroat Trout.
- Mercer Island Boat Launch: Peregrine Falcons.
- Mercer Slough: Green Heron and Freshwater Mussels. Large and Mixed Wetland, Open Water, Scrub Shrub, Emergent and Forested. Coho and Sockeye Salmon, Beach Spawning Sockeye Salmon, Resident Cutthroat Trout, Rainbow Trout, and Western Brook Lamprey.
- Meydenbauer Bay: Bald Eagles, Osprey, Common Loon, Western Pond Turtles, and Peregrine Falcons.
- OO Denny Park (Stream through Park): Resident Cutthroat Trout and Coho Salmon
- Saint Edward State Park: Bald Eagles, Pileated Woodpeckers, Waterfowl Concentrations.
- Sammamish River: Coho and Sockeye Salmon, Winter Steelhead, and Beach Spawning Sockeye Salmon.
- Thornton Creek: Summer and Fall Chinook Salmon, Coho and Sockeye Salmon, and Resident Cutthroat Trout
- Union Bay and University Slough: Bald Eagles, Green Herons, Common Loons, Western Pond Turtles, River Lamprey, and Waterfowl Concentrations. The wetlands at the mouth of University Slough, along the Union Bay Natural Area, marsh, Foster Islands, and shoreline associated with the University of Washington Arboretum provide nesting and loafing opportunities for Urban Dabbler Species, including Wood Ducks.
- Windermere Park: Bald Eagles.
- Yarrow Bay: Bald Eagles and Wetlands (associated with the lake or smaller tributary streams). Area is heavily developed as urban housing and industrial. Some of these have an open water component.
- Yarrow Bay (Tributary to Bay): Coho Salmon.
Specific Geographic Areas of Concern – Maps and Descriptions
Figure 1: Lake Washington GRP specific areas of concern.
Cultural Resources at Risk – Summary
Culturally sensitive sites are present within the Lake Washington area. Due to the sensitive nature of this information, details regarding the location and type of cultural resources present are not included in this document. However, in order to ensure that tactical response strategies do not inadvertently harm historical and culturally sensitive sites, Washington Department of
Archeology and Historic Preservation (WDAHP) should be consulted before disturbing any soil or sediment during a response action. WDAHP may assign a person to monitor cleanup operations, or provide a list of professional archeologists that can be contracted to monitor response activities.
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Information on the location of culturally sensitive sites is maintained by WDAHP and made available to Washington Department of Ecology for oil spill preparedness and response planning.
The Muckleshoot Indian Tribe, Samish Indian Nation, Snoqualmie Tribe, Suquamish Tribe, and Tulalip Tribes may also be able to provide information on cultural resources at risk in this GRP
area and should be consulted. After the Unified Command is established, information related to specific archeological concerns will be coordinated through the Environmental Unit.
Table 6‑1: LKWA-GRP Cultural Resource Contacts
|Washington Department of Archaeology and Historic Preservation||(360) 586-3065||Rob.Whitlam@dahp.wa.gov|
|Muckleshoot Indian Tribe||(253) email@example.com|
|Samish Indian Nation||(360) firstname.lastname@example.org|
|Snoqualmie Tribe||(425) 888-6551||Snoqualmie1855@snoqualmienation.com|
|Suquamish Tribe||(360) email@example.com|
|Tulalip Tribes||(360) firstname.lastname@example.org|
Discovery of Human Skeletal 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.
- All work must be stopped immediately and the Incident Commander and Cultural Resource Specialist notified if any person monitoring work activities or involved in spill response believes that human skeletal remains have been discovered.
- The Incident Commander is responsible for taking appropriate steps to protect the discovery. The immediate area of discovery should be flagged. Vehicles and equipment must not be permitted to traverse the discovery site. In no case should further disturbance be performed prior to consultation with WDAHP. Exposed human remains should not be left unattended.
- The Incident Commander (or representative) must immediately report the discovery to WDAHP, local law enforcement (with jurisdiction), and the local coroner (with jurisdiction). The coroner (or medical examiner) will determine whether the discovery site is a crime scene or human burial.
- If the remains are determined to be non-Native American, or connected with criminal activity, local law enforcement will take charge of the discovery site and remains.
- If the remains are determined to be Native American, not related to a crime scene, a tribal archaeologist, state archaeologist, and the Incident Commander will confer on a treatment plan for the remains.
Procedures for the Discovery of Cultural Resources
All work must be stopped immediately and the Incident Commander and Cultural Resource Specialist notified if any person monitoring work activities or involved in spill response believes that they have encountered cultural resources. 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 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 and traps
- Culturally modified trees
- Physical locations or features (traditional cultural properties)
Historic cultural material (May include any of the following items over 50 years old):
- Bottles, or other glass
- Milled wood, brick, concrete, metal, or other building material
- Trash dumps
- Homesteads, building remains
- Logging, mining, or railroad features
- Piers, wharves, docks, bridges, dams
If WDAHP believes that the discovery is a cultural resource, the Incident Commander will take appropriate steps to protect the discovery site:
- The immediate area of the discovery site should be flagged. Vehicles or equipment must not be permitted to enter the discovery site. Work in the immediate area can not resume until treatment of the discovery has been completed.
- The Incident Commander (or representative) must contact WDAHP and arrange for the discovery to be evaluated by a professional archaeologist. The archaeologist will determine whether the discovery is potentially eligible for listing on the National Register of Historic Places. (36 CFR 60.4)
- The professional archaeologist will consult with WDAHP on the eligibility of the discovery for entry into the National Register. If WDAHP determines that the discovery is eligible, they will consult with the Incident Commander to determine an appropriate treatment for the discovery.
- If adverse impacts to an eligible site cannot be avoided, a treatment plan will be developed and implemented.
The Secretary of the Interior’s Standards for Archaeological Documentation must be followed; including provisions for research design, reporting, and curation of recovered material and samples. The particular data recovery measures applied to any given historic property will depend on the development of research questions, and the design of excavation strategies to acquire the data needed to answer those questions. Field notes, maps, plans, profiles, and photographs will document the process. The final report will follow style guidelines of the professional archaeological journal American Antiquity; it will synthesize the data collected and address the research questions posed.
Refer to Section 9403 of the Northwest Area Contingency Plan for National Historic Preservation Act Compliance Guidelines during an emergency response.
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. Appendix “Economic Resources at Risk” in the Table of Contents provides a list of economic resources for this GRP area.
Flight Restriction Zones: Flight restriction zones may be recommended by the Environmental Unit (Planning Section) for the purpose of minimizing disturbance that could result in injury to wildlife during an oil spill. By keeping a safe distance or altitude from identified sensitive areas, pilots can minimize the risk of aircraft/ bird collisions, prevent the accidental hazing of wildlife into oiled areas, and avoid causing abandonment of nests or marine mammal pupping areas. Implementation of Flight Restriction Zones will take place within the Air Operations Branch (Operations Section) after a Unified Command is formed. The Planning Section’s Environmental Unit will work with the Air Ops Branch Director to resolve any potential conflicts with flight activities that are essential to the spill response effort. Typically, the area within a 1,500 ft radius and below 1,000 ft in altitude is restricted to flying in areas that have been identified as sensitive. However, some areas have more restrictive zones. 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 Section 9301.3.2 and Section 9301.3.3 of the Northwest Area Contingency Plan for more information on the use of aircraft and helicopters in open water and shoreline responses.
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Hazing: The use of boats and watercraft are usually restricted within 200 yards of offshore National Wildlife Refuge sites or other sensitive areas. Response organizations should immediately request a waiver from National Marine Fisheries Service [NMFS] and/or U.S. Fish and Wildlife Service regarding the inadvertent approach or hazing of marine mammals that may be encountered during open water response operations. After a Unified Command is formed, the Wildlife Branch (Operations Section) in consultation with the appropriate trustee agencies and the Environmental Unit will evaluate and recommend hazing options for the purpose of keeping un-oiled birds and marine mammals away from oil during a spill. Hazing options might include the use of acoustic or visual deterrent devices, boats, aircraft or other situation-appropriate tools. For more information see the Northwest Wildlife Response Plan (NWACP Section 9310) and Northwest Area Wildlife Deterrence Resources (NWACP Section 9311).
Oiled Wildlife: Attempting to capture oiled wildlife can be hazardous to both the animal and the person attempting the capture the animal. Response personnel should not approach or attempt to recover oiled wildlife. Responders should report their observations to the Wildlife Branch so appropriate action can be taken. Information provided should include the location, date, and time of the sighting, and the estimated number and kind of animals observed. Early on in the response, before a Unified Command is established, oiled wildlife sightings should be reported to Washington Emergency Management Division. For more information see the Northwest Wildlife Response Plan (NWACP Section 9310).