Upper Green River GRP

Table of Contents


Site Description

This section provides a description of the physical features, hydrology, climate, and winds in the Upper Green River GRP planning area, and an oil spill risk assessment in Section 2.6. The planning area is approximately 120 square miles and resides within the boundaries of King County. The area is remote, with no towns, cities, or major roadways located here. The Upper Green River GRP is bordered by the Green River/Duwamish GRP to the west, and the Upper Yakima River GRP to the east. It begins at Stampede Pass, in the Cascades, and follows Sunday Creek to the southwest until it empties into the main stem of the Green River. From there the planning area continues west, including the reservoir above the Howard Hanson Dam, and ends at the dam itself. Portions of WRIA 8 (Cedar-Sammamish) and WRIA 9 (Duwamish-Green) fall within this planning area.

Physical Features

The Upper Green GRP planning area covers approximately 120 square miles of mountainous and heavily forested land between the top of the Howard Hanson Dam and the crest of the Cascades at Stampede Pass. The area encompasses almost 24 miles of the Green River and more than 20 tributary creeks. The Green River Watershed is managed by the City of Tacoma and used as a drinking water source for Kent, Covington, Lakehaven, and Tacoma (Tacoma Public Utilities). This area is remote, with no cities, populated towns, or major roadways.

Open to read more

Development in the area is very limited. The Howard Hanson Dam and Reservoir occupy the westernmost portion of the area. The dam was completed in 1962 and is used to control flooding in the Green River Valley (Stein 2001). Upriver from the reservoir, the only developments are 45 miles of BNSF rail track, a power line transmission corridor and a network of US Forest Service roads. The roads provide access for timber harvesting by the Mount Baker – Snoqualmie National Forest. No tribal reservations exist in the area; however, 13 tribes have potential interests in the area due to their usual and accustomed fishing places.

^ top


The Upper Green River sources from the western slope of Blowout Mountain, in the Cascade Range. Its tributaries drain from the western slopes of hills in Snoqualmie National Forest. It flows northwest for 8 miles before crossing BNSF tracks, where it turns west and parallels the rail line until it enters the reservoir created by the Howard Hanson Dam. This flood control dam manages the flow of water down to sea level from an elevation of 1,206 feet, with a reservoir capacity of 106,000 acre/ft (USACE 2014). The Upper Green’s main tributary is Sunday Creek, which begins near the rail tunnel at Stampede Pass, and drains west for 8 miles to join the Green River near River Mile (RM) 84.Other tributaries within the planning area include Boundary Creek, Champion Creek, CharleyCreek, Cougar Creek, Eagle Creek, East Creek, East Fork Friday Creek, Friday Creek, Gale Creek, Intake Creek, Lester Creek, McCain Creek, Piling Creek, Rock Creek, Sawmill Creek, Smay Creek, Snow Creek, Sylvester Creek, West Creek, West Fork Smay Creek, and Wolf Creek.

Open to read more

As with most of Western Washington, the rainy season is considered to begin in October and end in May or June. At this elevation in the Cascades (1000 to 3900 feet above sea level), this precipitation is more likely to accumulate as snow. The greatest flows in this upper portion of the watershed occur in late spring, as the snow begins to melt, and in late fall or early winter, when heavy rains begin but the temperatures have not yet dropped below freezing.

The planning area almost fully resides within the boundaries of Water Resource Inventory Area Green-Duwamish (WRIA 9), with a small portion overlapping Cedar-Sammamish (WRIA 8).

Green-Duwamish (WRIA 9): The Green-Duwamish watershed is situated in southern Puget Sound and comprises most of southern King county, including south Seattle and its adjacent suburban areas of Kent, Des Moines, Covington and other cities. On its west side it is bounded by Puget Sound and its east side includes portions of the Cascade Mountain range. This watershed includes only one major river, the Duwamish-Green River which originates in the Cascade Mountains. The Green River is the source for much of the drinking water for the Tacoma area and includes the Howard A. Hanson Dam which is used for flood control and reservoir purposes. Average precipitation ranges from 30-35 inches per year in the coastal areas to 70 inches in the mountains. Most of this precipitation arrives during the winter months when water demands are the lowest, and only a fraction becomes available for human and economic uses. During the summer, the snowpack is gone; there is little rain so low stream flows are dependent on groundwater inflow (WA Dept. of Ecology).

Cedar-Sammamish (WRIA 8): The Cedar Sammamish Watershed is situated in southern Puget Sound and comprises the northwestern and part of central King county, including Seattle and its adjacent suburban areas. On its west side it is bounded by Puget Sound and its east side includes portions of the Cascade Mountain range. Average precipitation is 30-35 inches per year (WA Dept. of Ecology).

^ top

Climate and Winds

Average temperatures at Stampede Pass vary from winter lows in the twenties to summer highs of 65 degrees. The Pass averages 87 inches of rain and 439 inches of total snowfall, with an average snow depth of 40 inches. The ground is generally clear of snow between July and October, with the deepest average snowpack of almost 9 feet in March (WRCC 2016)

Open to read more

Prevailing winds in the Stampede Pass area are generally towards the west-southwest in April through October, and to the east in November through March (WRCC 2002). Wind speed consistently averages 7 to 8 miles per hour year-round (WRCC 2006).

^ top

Tides and Currents

There are no tidally influenced areas within the planning area.

The overall river current is controlled by the natural slope of the river from the foothills and input from tributary creeks (especially during heavy instances of precipitation). In the reservoir area, current is determined by whether the dam floodgates are opened or closed. The reservoir level is usually dropped in late winter, to make room for the inflow of the spring thaw. Marginal drainage is maintained in the summer for downstream water usage and fish habitat, and flow just upstream of the reservoir can be nearly stagnant. Average water volumes are 1200 cubic feet per second (cfs) at the gage below the dam, with summer flows below 300 cfs, and winter flows above 1600 cfs (USGS).

Risk Assessment

The Upper Green River is plentiful in natural, cultural, and economic resources, all at risk of injury from oil spills. Due to the remote nature of this area, many common oil spill risks are not present. There are no public roads, commercial or recreational boating, airports, or oil pipelines in the planning area. Road traffic is radio-monitored and limited to railroad staff, public agency staff, and potentially lumber equipment.

Open to read more

Rail Transportation and Facilities: Rail companies transport oil via manifest trains in this area. 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.

BNSF owns the commercial rail track in this planning area, although other rail companies may operate trains on BNSF tracks. The BNSF Stampede Subdivision runs parallel to either the Green River or Sunday Creek throughout the planning area. BNSF maintains a refueling station in Lester, at about river mile 80, where three aboveground tanks have a combined storage capacity of 2,550 gallons of diesel (WA Dept. of Ecology).

Other Spill Risks: Other potential oil spill risks in the area include fuel storage areas (including waste oil storage), on-shore or nearshore activities where heavy equipment is being operated or stored, and the migration of spilled oil through soil on lands adjacent to the river or its tributary streams.

^ top

Resources at Risk

This section provides a summary of natural, cultural, and economic resources at risk in the planning 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, wildlife deterrence, and oiled wildlife can be found near the end of this chapter.

Open to read more

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 Section 4 (Response Strategies and Priorities) because it’s 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.

The information provided in this chapter can be used in:

  • Assisting the Environmental Unit (EU) and Operations Sections 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.

^ top

Natural Resources at Risk – Summary

Most biological communities are susceptible to the effects of oil spills. Plant communities on land, aquatic plants; microscopic plants and animals; and larger animals, such as fish, amphibians and reptiles, birds, mammals, and a wide variety of invertebrates, are all potentially at risk from smothering, acute toxicity, and/or the chronic long-term effects that may result from being exposed to spilled oil.

Open to read more

This area contains a wide variety of aquatic, riparian, and upland habitats. These habitats support many of Washington’s anadromous salmonid species as well as a complex diversity of other wildlife including mammals, birds, and amphibians. Due to their life histories and/or behaviors, some of these species are unlikely to be directly oiled during a spill incident but may be disturbed by other operations such as cleanup, reconnaissance, or fire suppression activities. Some of the bird species are resident throughout the year, but many others seasonally migrate outside the basin. A number of the species found in this area are classified as threatened or endangered under the Federal Endangered Species Act or Washington State guidelines.

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)
  • State Endangered (SE)
  • State Threatened (ST)
  • State Sensitive (SS)

Federal and State listed, candidate, and species of concern that may occur within this area, at some time of year, include:


  • Common loon [SS]
  • Marbled murrelet [FT/SE]
  • Northern spotted owl [FT/SE]*
  • Yellow-billed cuckoo [FT]*


  • Canada lynx [FT/SE]*
  • Gray Wolf [FE/SE]*


  • Bull trout [FT/SC]
  • Chinook salmon [FT/SC]
  • Steelhead [FT]

* Unlikely to be directly oiled during a spill incident.

^ top

General Resource Concerns


  • River and streams in this region provide spawning and rearing habitat for a number of salmonid species including Chinook, chum, and coho salmon, as well as cutthroat (resident and coastal), rainbow, bull trout, and steelhead trout. Passerine birds commonly nest in riparian habitat during the spring and summer.
Open to read more
  • Wetlands in this region range from freshwater emergent, freshwater forested, freshwater ponds and lakes. All wetland types support a diverse array of bird, insect and fish and wildlife species.


  • Salmonid species are present throughout this region, with spawning occurring throughout the area’s rivers and streams. Juvenile salmonids use these streams for feeding, rearing, and as migration corridors.


  • Sensitive nesting species in the region include raptors (bald eagles and osprey), passerine birds, and waterfowl (harlequin ducks and common loons).
  • Elk concentrations found throughout riparian areas throughout winters.

^ top

Specific Geographic Areas of Concern – Overview

  1. 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.
  2. 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.

^ top

Specific Geographic Areas of Concern – Maps and Descriptions

Figure 1: Specific geographic areas of concern for the Upper Green River GRP.

^ top

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.

Open to read more

During a spill response, after the Unified Command is established, information related to specific archeological concerns will be coordinated through the Environmental Unit. In order 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. 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. 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: UGR-GRP Cultural Resource Contacts

Contact Phone Email
Washington Department of Archaeology and Historic Preservation (360) 586-3080 Rob.Whitlam@dahp.wa.gov
Lummi Nation (360) 312-2257,
(360) 961-7752
Muckleshoot Tribe (253) 876-3272 laura.murphy@muckleshoot.nsn.us
Nooksack Indian Tribe (360) 592-5176
(360) 305-9126
Sauk-Suiattle Tribe (360) 436-0347 njoseph@sauk-suiattle.com
Stillaguamish Tribe of Indians (360) 652-3687 x14 KLyste@stillaguamish.com
Swinomish Indian Tribal Community (360) 466-7352 lcampbell@swinomish.nsn.us
The Suquamish Tribe (360) 394-8529 dlewarch@suquamish.nsn.us
Tulalip Tribes (425) 239-0182 ryoung@tulaliptribes-nsn.gov
Upper Skagit Tribe (360) 854-7009 sschuyler@upperskagit.com

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 (photographing human remains is prohibited to all except the appropriate authorities). Refer to Section 9403 of the Northwest Area Contingency Plan for National Historic Preservation Act Compliance Guidelines 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 work must be stopped immediately and the Incident Commander and Cultural Resource Specialist notified. 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 water craft
  • 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
  • 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

^ top

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 6A of this chapter provides a list of economic resources for this planning area.

^ top

General Information

Flight Restriction Zones: Flight restriction zones may be recommended by the Environmental Unit (Planning Section) for the purpose of reducing disturbances that could result in injury to wildlife during an oil spill. By keeping a safe distance or altitude from identified sensitive areas, pilots can lessen the risk of aircraft/bird collisions, prevent the accidental hazing of wildlife into oiled areas, and avoid causing the abandonment of nests.

Open to read more

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-foot radius and below 1,000 feet 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.

Wildlife Deterrence: After a Unified Command is formed, the Wildlife Branch (Operations Section), in consultation with the appropriate trustee agencies and the Environmental Unit, will evaluate wildlife deterrent options for the purpose of keeping un-oiled birds away from oil during a spill. The “Bird Deterrence Unit” in the Wildlife Branch would participate in operations. Deterrence 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. Response personnel should not approach or attempt to recover oiled wildlife. Responders should report their observations of oiled wildlife 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).

^ top