Snake River – Ice Harbor Pool GRP

Table of Contents


Site Description

This section provides a description of the physical features, hydrology, climate, and winds in the Snake River Ice Harbor Pool GRP planning area, and an oil spill risk assessment. The planning area covers 256 square miles, and includes the 31.8 mile reach of the Ice Harbor Pool (a.k.a. Lake Sacajawea) from the upstream side of the Ice Harbor Lock and Dam (located at river mile 9.7) to the downstream side of the Lower Monumental Dam (at river mile 41.5). The area around Lake Sacajawea is rural with no large towns present. Pasco and Kennewick are the largest cities nearby, both located downstream of the Ice Harbor Dam near the confluence of the Snake and Columbia Rivers. The area predominately resides in Water Resource Inventory Area Lower Snake (WRIA 33), but also contains small portions of the Esquatzel Coulee (WRIA 36) to the north, and Walla Walla (WRIA 32) to the south. The planning area falls within the boundaries of Franklin and Walla Walla counties.


Physical Features

Volcanic activity built up a stratum of mud, ash, and lava in the geologic column in the area now known as eastern and central Washington and Oregon during the Eocene (55.8-33.9 million years ago), Oligocene (33.9-23 million years ago), and Miocene (23-5.3 million years ago) Epochs (Smith 2011). Basalt flows then covered the area, known as the Columbia River Basalt Group, in layers, forming a strong foundation of basaltic rock at least one mile thick (Foster 2008). Subsequent lava and ash eruptions raised the Cascade Mountains during the Miocene Epoch, and the mountains began to lift when hundreds of volcanoes erupted during the Pleistocene Epoch (2.6 million – 11,700 years ago). As the mountains rose, the Snake and Columbia Rivers carved out deep gorges. Towards the end of the Pleistocene (~16,000-14,000 years ago) the Missoula floods battered these gorges over 100 times when the glacial dam forming Glacial Lake Missoula was repeatedly breached, releasing high velocity debris-filled waters to a height of 900 feet and scouring the landscape with a discharge of 10 million cubic feet per second (Lee 2009). This series of events has been described as one of the greatest flood occurrences in the history of the earth.  Basalt bluffs and cliffs prevail throughout most of the length of the Ice Harbor Pool, but gradually flatten toward the end of the gorge craved by the Snake River until it reaches its mouth at the Columbia (USACE 1977). Shoreline habitats along this section of the Snake River can be characterized as: exposed rocky headlands, wave-cut platforms, pocket beaches along exposed rocky shores, sand beaches, sand and gravel beaches, sand and cobble beaches, sheltered rocky shores, and sheltered marshes (NOAA 1993).


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Human activity has also had a major impact on the Snake River. The U.S. Army Corps of Engineers (USACE) has shape the Snake River into its current form through the construction of 15 dams; structures designed to provide irrigation water, hydroelectricity, and improved navigation. The four dams in the Lower Snake River Project were built primarily to create a navigable channel from the mouth of the Snake River to the beginning of Hells Canyon, located downstream of Lewiston, Idaho near the borders of eastern Washington, eastern Oregon, and western Idaho. The Lower Snake River dams, in downstream order, include: Lower Granite Lock and Dam, Little Goose Lock and Dam, Lower Monumental Lock and Dam, and Ice Harbor Lock and Dam.

The dams on both the Snake and Columbia allow the rivers to function as an industrial transportation corridor, with ships running import containers and autos east from Portland, OR and Vancouver, WA through a series of locks up to the Tri-Cities area (Kennewick, Pasco, and Richland, WA), before continuing east on the Snake River to Lewiston, Idaho (PNWA). As of 2014, more than four million tons of petroleum products were received at terminals in Portland each year, with approximately half of that volume barged upriver to inland ports. The Columbia and Snake River corridor provides a route for the transport of grain from farms in the interior of the country to the Columbia River’s gateway at the Pacific Ocean. This corridor is the number one export route in the nation for wheat and barley, number two for soybeans, and the third largest grain export gateway in the world. Dams within the corridor provide irrigation, flood control, and hydroelectric power to Washington, Oregon, and Idaho.

The Lower Snake River is rich in archaeological resources. Evidence shows that the Columbia Plateau was inhabited as early as 11,500 years ago, and that settlements were established as early as 11,230 years ago (Ames et al, 1988; Bureau of Indian Affairs, 2013). Three Archaeological Districts in the region are listed on the National Register of Historic Places and numerous other sites are known, including: villages, fishing sites, temporary camps, storage pits, burials, and rock art such as pictographs and petroglyphs.  Well before the establishment of white settlements, Native Americans had developed the largest trading center in the Northwest at the Long Narrows of The Dalles/Celilo Falls area on the Columbia River. Celilo is believed to be the oldest continuously inhabited community on the North American continent (Dietrich 1995). The center linked a trade network that extended along the entire Pacific Coast and inland to the Great Plains.

Europeans and Americans began exploring and trading in the Pacific Northwest in the 18th century with trade items being transported into the Snake River Basin during that period. First contact occurred in the region in 1805 when the Lewis and Clark Expedition traveled down the Snake and into the Columbia River. Upon arriving at The Dalles/Celilo Falls area, Clark noted the settlement as being a “great mart of trade”. Other expeditions of exploration soon followed, and trading operations were established. The Northwest Company built Fort Nez Perce in 1818 near the mouth of the Walla Walla River on the Columbia (Garth 1952). The fort was taken over as a trade station by the Hudson Bay Company in 1821, further impacting the regional economy and influencing relations between Euro-Americans and Native American (Garth 1952). Missionaries arrived in the 1830s and were followed by settlers in the 1840s.

From the mid to late 1800’s, numerous white settlements were established along both the Columbia and Snake Rivers. People migrated into the area by following the Oregon Trail or arriving by ship via the Pacific Ocean. Gold was discovered near Fort Colville in 1855 prompting an influx of miners at the same time treaty negotiations were underway with Native American Tribes. The earliest treaties were signed in 1855; however, increasing conflicts led to several years of war between Native Americans and the United States government (Beckham 1998). Oregon became a state in 1859, followed by Washington and Idaho in 1889 and 1890, respectively.

With traders, farmers, ranchers, and miners arriving in the area, steamboats began navigating the Snake River in the 1860s. Steamboats traversed over 60 sets of rapids in the free flowing river when traveling between Pasco, Washington and Lewiston, Idaho. The USACE started modifying the Columbia River to aid vessel navigation as early as 1873 by removing obstructions; from 1876 to 1915 canals were built (Bureau of Indian Affairs, 2013). The first dam was constructed on the Snake River in 1901. Between the 1950’s-1980’s, the USACE started the Lower Snake River Project with the construction of four dams in eastern Washington, bringing the total number of dams on the Snake River to 15.

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The Snake River is the 13th longest river in the United States (Krammerer 1990). The Ice Harbor Pool is approximately 32 miles in length and has a drainage area encompassing 103,200 square miles. The Ice Harbor Dam, which creates Lake Sacajawea, is 2,822 feet long and about 100 feet tall. The elevation of Lake Sacajawea during normal dam operations at full pool is 440 feet. The minimum pool elevation is 437 feet, and the maximum capacity of the pool is 446 feet. Prior to the construction of the dams the maximum unregulated historical peak discharge was 409,000 cubic feet per second (cfs) (1894). Currently, the average monthly outflow of both the Ice Harbor and Lower Monumental Dams is approximately 34,000 cfs (USACE 2016).

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Portions of Water Resource Inventory Areas Walla Walla (WRIA 32), Lower Snake (WRIA 33), and Esquatzel Coulee (WRIA 36) fall within the geographic boundaries of this plan.

Walla Walla (WRIA 32): The Walla Walla Watershed includes the Walla Walla River and the Touchet River with their numerous tributary creeks and streams. The annual precipitation in the watershed ranges from less than 10 inches per year near its confluence with the Columbia River, to 45 inches per year in the higher elevation mountainous areas. Only a fraction of this precipitation becomes groundwater available for human and economic uses. Most of the precipitation arrives during the winter months, when water demands are the lowest. During the summer, the snowpack is gone, there is little rain, and naturally low stream flows are dependent on groundwater inflow (WA Dept. of Ecology).

Lower Snake (WRIA 33): The Lower Snake Watershed includes a portion of the Snake River and its numerous tributary creeks and streams. The annual precipitation in the watershed ranges from 8 inches per year near its confluence with the Columbia River, to a little over 10 inches in the higher elevations. Only a fraction of this precipitation becomes groundwater available for human and economic uses. Most of the precipitation arrives during the winter months, when water demands are the lowest. During the summer, the snowpack is gone, there is little rain, and naturally low stream flows are dependent on groundwater inflow (WA Dept. of Ecology).

Esquatzel Coulee (WRIA 36): The Esquatzel Coulee Watershed includes a number of small streams that are tributary to the Columbia River. Many of these smaller streams are seasonal. The annual precipitation in the watershed ranges from 7 inches per year in the Mattawa area, to over 10 inches in the higher elevations. Only a fraction of this precipitation becomes groundwater available for human and economic uses. Most of the precipitation arrives during the winter months, when water demands are the lowest. As spring turns to summer, snowpack melts. This causes stream flows to increase, but after the snowpack is gone, stream flow declines considerably. River flows then become dependent on groundwater inflow, late summer glacial melting, and rare precipitation events. This means that both groundwater and surface water are least available when water demands are the highest (WA Dept. of Ecology).

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Climate and Winds

The climate in this area of the Snake River is arid, with an annual precipitation of 10.4 inches, with over 50% occurring between November and March and little rain in summer. Annual snowfall is 5.8 inches, with more than 75% occurring in December and January. Much of the precipitation occurs as drizzle or intermittent rains from winter through spring with extended periods of cloudiness. A few regional storms with showers occur in winter but heavy rain is rare. Only a small percentage of the precipitation becomes groundwater available for human use. Much of the area within a few miles of the riverbanks is farmed through irrigation using water pulled from the Snake River. The average annual temperature is 53.9°F, ranging from a mean low of 34.2°F in January, to a mean high of 74.2°F in July and August. Recorded temperature extremes are -22°F and 111°F.

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The climate of the lower Snake River is greatly influenced by prevailing southwesterly winds in both summer and winter, with the Cascade Mountain Range shielding the area from winds flowing east from the Pacific Ocean. Average wind speeds usually range from 7-8 mph (Jackson & Kimmerling 1993). Winter storms can include strong winds. Thunderstorms in July and August usually produce little rain but may include strong gusts of wind. Wind erosion, the primary cause of dust emissions in the semi-arid climate of this area, is common in spring and fall. High winds and dry soil conditions may result in dust storms.

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Tides and Currents

There are no tidally influenced areas within the planning area. The river’s flow is governed strictly by dams on the Snake River, with USACE determining exactly when and how much water is allowed to pass through the spillways. Nearly all flow into the Ice Harbor Pool comes from the Snake River after having passed through the Lower Granite, Little Goose and Lower Monumental Dams in Washington State. The Ice Harbor Pool is very lake-like, with dam controlled outflow rates. The lowest flow rates typically occur during the late summer, autumn, and winter months. Higher flows occur during the spring snow melt. The upper reach of the reservoir below the Lower Monumental Dam may attain higher flows than the lower reach, especially during spring runoff. Nearer to the Ice Harbor Dam, the current is practically nonexistent, except for the area in front of the spillway and powerhouse, which may have strong currents and undertows that are very dangerous.


Risk Assessment

The Snake River is plentiful in natural, cultural, and economic resources, all at risk of injury from oil spills. Potential risks to these resources include commercial vessels and barges, road systems, rail transportation and facilities, aircraft, recreational boating, and other oil spill risks. Industrial development along this reach of the river consists of storage facilities for grain and irrigation pumping stations.

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Oil Types: Both refined petroleum products and crude oil are transported in bulk within this planning area.

Crude oil and refined products contain a mix of hydrocarbons with varying properties; different types of crude oil and refined products will behave differently when spilled. Recent changes in oil production have led to an increase in the movement of Bakken light crude and diluted bitumen from Canada transported through the planning area via rail.

Crude oil from the Bakken fields in North Dakota has properties similar to gasoline or diesel, and poses a higher risk of fire because much of it will evaporate quickly into flammable vapors. Unlike gasoline, the heavier hydrocarbons in the crude will persist in the environment after the light ends evaporate or burn. Bitumen from the oil sands in Alberta, Canada, is heavy, almost asphalt-like, until it is mixed with lighter oil products known as diluents to create diluted bitumen. Once mixed, the diluted bitumen will initially float on water after being spilled. Environmental conditions, such as the density of the receiving waters and sediment load of the receiving waters, will affect how long diluted bitumen floats. As the light diluents evaporate, the remaining heavy constituents may sink into the water column (NASEM 2016). There are specific response actions recommended for non-floating oils, detailed in the Non-Floating Oil Spill Response Tool in the Northwest Area Contingency Plan (NWACP), Section 9412.

Commercial Vessels and Barges: The Columbia/Snake corridor offers many port facilities, stretching from Astoria, Oregon to Lewiston, Idaho. The Dalles Lock reports that an average of eight million tons of cargo, mostly grain and petroleum products, pass through each year (USACE 2015). Future oil movement along the Columbia River Vessel Route is estimated to reach 566 million gallons/year (based on annual estimates and 2013 data) (WA Dept. of Ecology 2015). The potential for vessel collisions, allisions, or groundings presents a significant spill risk in the planning area. Commercial vessels, including tug and barge combinations, carry substantial amounts of heavy and blended fuel oils and other petroleum products.

Road Systems: Vehicle traffic on roadways pose an oil spill risk in areas where they run adjacent to the shorelines, or cross over lakes, rivers, creeks, and ditches, that drain into the Snake River. Several smaller roads run parallel to the river, including Washington Highway 263. There are no highway bridges that cross the Snake River in the planning area. However, there are several smaller bridges or causeways where vehicles cross tributaries or small lakes along shore. A vehicle spill onto one of these bridges or roadways can cause fuel or oil to flow from hardened surfaces into the Snake River or its tributaries. 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.

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

Union Pacific (UP) owns the commercial rail track in this planning area. Known as the Portland Subdivision, the track runs parallel to the river on the south bank (river left) throughout the Snake River Ice Harbor Pool. UP’s trains generally contain mixed cargo loads, and may include the transport of hazardous materials and Bakken crude oil.

Aircraft: The Lower Monumental State Airport is the only airport within the SIH-GRP planning area. Managed by Washington State Department of Transportation (WSDOT), it is primarily used for recreational and transit purposes. Since this airport is close to the river, the potential exists for aircraft failures during inbound or outbound flights that result in a spill by releasing aviation fuel to the Snake River or its tributaries.

Recreational Boating: Accidents involving recreational water craft on the Snake River have the potential to result in spills of a few gallons of gasoline up to hundreds of gallons of diesel fuel. Examples of such accidents might include vessel collisions, allisions, groundings, fires, sinking, or explosions. Bilge discharges and mishaps during boat refueling operations are generally the most common types of oil spills to occur from recreational boating.

Other Spill Risks: Other potential oil spill risks in the area include, dam turbine mechanical failures, fuel storage areas (including waste oil storage), road run-off during rain events, on-shore or near shore 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.


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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 provided in the appendix.

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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.

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Natural Resources at Risk – Summary

This area is composed of a wide variety of aquatic, riparian, and upland habitats. These varied habitats support a complex diversity of wildlife species, including large and small mammals, songbirds, birds of prey, upland birds, and waterfowl, as well as numerous reptiles and amphibians. Some species are resident throughout the year; while others seasonally migrate through the sub-basin.

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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, others (due to their life histories and/or behaviors) are unlikely to become directly oiled during a spill incident but may be disturbed by response operations such as cleanup and reconnaissance. Some of the bird species are resident throughout the year, but many others seasonally migrate through the area.

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 listed below:

  • 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:


  •  None expected


  • American white pelican [ST]
  • common loon [SS]
  • ferruginous hawk [ST]
  • sandhill crane [SE]
  • yellow-billed cuckoo [FT/SE]


  • bull trout [FT]
  • chinook salmon, (Snake River, Fall) [FT]; (Snake River, Spring/Summer) [FT]
  • sockeye salmon (Snake River) [FE]
  • steelhead trout (Snake River) [FT]

Critical habitats:

These are the specific areas occupied by an endangered or threatened species 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 designated critical habitat within this area.

  • bull trout
  • chinook salmon
  • sockeye salmon
  • steelhead

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General Resource Concerns


  • Wetlands in this region include areas along the main stem of the Snake River. All wetland types support a diverse array of bird, insect, fish, and wildlife species.
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  • Side channels and impounded areas provide feeding and resting areas for waterfowl and herons and are important rearing areas for juvenile fish.
  • 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.
  • Stream mouths are concentration areas for anadromous fish and are feeding areas for a variety of birds including American white pelican.
  • Riparian vegetation is heavily used by a variety of wildlife and may also improve nearshore fish habitat. Riparian scrub and woodlands support a high diversity and abundance of birds that depend on this habitat for nesting and rearing young, as well as for forage and cover during migration and overwintering.
  • Human-made structures such as pilings and rock jetties may be used as roosting or nesting areas for a variety of birds.
  • Cliffs, bluffs, and rock outcroppings provide roosting or nesting habitat for various birds of prey, upland birds, and bats.
  • The riverbed habitats in this area consist primarily of soft sediments, such as clay, mud, sand, and gravel and support a variety of aquatic, semi-aquatic, and bottom dwelling organisms such as the invertebrate larvae of insects (caddis flies, mayflies, and dragonflies and stoneflies), snails and freshwater mussels, and crayfish. Many species of amphibians and bottom-dwelling fish also rely on this habitat, as do other animals that forage there. This entire stretch of the Snake River is Critical Habitat for sockeye, chinook, steelhead, and bull trout.


  • Freshwater mussels, such as the California floater, have been reported to exist within this general area although no documented occurrence data was found for this particular reach.
  • Various salmonids (including the listed bull trout, chinook and sockeye salmon, and steelhead) are present in the river system above the Ice Harbor Dam throughout the year. Thousands of juvenile salmonids move downstream through this region and use this area for rearing and foraging as they prepare for migration to the ocean. Returning adult salmonids of various types and stocks support significant tribal and recreational fisheries.
  • In addition to salmonids, numerous other species of fish (including bass, crappie, catfish, suckers, and white sturgeon) exist within this reach of the Snake River. These species all contribute to recreational fisheries and provide important contributions to stream ecology.
  • Anadromous fish (other than salmon) in this region include American shad and Pacific lamprey.


  • Great blue herons are nesting residents and may be found foraging year-round throughout the region. In addition, the black-crowned night-heron breeds on several islands in the Snake River.
  • Nesting raptors in the area include bald eagles, ferruginous hawks [ST], burrowing owls, Swainson’s hawks, and prairie falcons.
  • American white pelicans [ST] are known to occur in small groups near the mouth of the Snake River during spring and fall migrations and may also be present along the river itself.
  • Migratory and wintering waterfowl and shorebirds – Large concentrations occur throughout this entire reach of the Snake River particularly fall through spring. Hundreds to thousands of geese, and dabbling ducks may occupy this region during this period. Both resident and migratory waterfowl heavily utilize the islands, backwaters, wetlands, and adjacent uplands of the region from fall through spring. The islands in this region also provide nesting habitat for resident waterfowl.
  • Resident and migratory songbirds heavily utilize riparian habitats year-round and are susceptible to oiling if riparian vegetation and riverbanks become contaminated.
  • Mammals common to the reach include deer and various semi-aquatic species such as muskrat, beaver, river otter, etc. Semi-aquatic mammals are largely dependent on riverine areas, ponds, tributaries, and riparian forests for den sites and foraging areas.
  • Amphibians and reptiles are found throughout this area.

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Specific Geographic Areas of Concern – Overview

To improve habitat, the Army Corps of Engineers has established numerous Habitat Management Units (HMUs) along the Snake River. The size and complexity of these HMUs varies, but many of them include irrigation, tree and shrub plantings, food plots, nesting and brooding cover, brush piles, and nesting structures that attract wildlife. Other significant wildlife areas, in addition to those habitats provided by HMUs, include shorelines with natural riparian vegetation, islands, wetlands, stream and river mouths (both free-flowing and impounded), and shallow backwater areas – especially adjacent to natural riverbanks. Public parks, private lands, and recreational areas surround the river. Specific areas of concern are listed below and depicted on the map in Figure 6.1 (near the end of this section). The number that precedes the area name in the list (below) relates to the numbered area on the map.

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  1. Charbonneau USACE, Habitat Management Unit (~RM 12, south): Approximately 100 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, bird watching and wildlife viewing. Waterfowl concentrations area. Shrub-steppe habitat.
  2. Levey Park (~RM 13, north): Approximately 50 acres, public day-use and fishing area administered by the US Army Corp of Engineers. Boat launch. Waterfowl concentration area. Shrub-steppe habitat.
  3. Big Flat HMU (~RM 15, north): Approximately 920 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, primitive camping sites, vault toilet, bird watching and wildlife viewing, one-lane boat ramp (into Dalton Lake only). Waterfowl concentration area. Ring-necked pheasant present. Wetland habitat.
  4. Fishhook HMU (~RM 18, south): Approximately 217 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, bird watching and wildlife viewing. Waterfowl concentration area. Ring-necked pheasant present. Wetland habitat.
  5. Lake Emma (~RM 19): Year-round recreational fishing area created by railroad fill. Lake ~45 acres and adjacent to the river main stem. Waterfowl concentration area.
  6. Lost Island HMU (~RM 22-24, north): Approximately 162 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, bird watching and wildlife viewing. Waterfowl concentration area. Ring-necked pheasant and mule deer present. Wetland habitat.
  7. Hollebeke HMU (~RM 25, south): Approximately 247 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, bird watching and wildlife viewing. Waterfowl concentration area. Ferruginous hawk, prairie falcon, Swainson’s hawk, and ring-necked pheasant present. Wetland and shrub-steppe habitats.
  8. Snake River Jct. HMU (~RM 26, north): Approximately 25 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, bird watching and wildlife viewing. Waterfowl concentration area. Ferruginous hawk, prairie falcon, Swainson’s hawk, and ring-necked pheasant present. Wetland habitat.
  9. Walker HMU (~RM 30, south): Approximately 90 acres, public day-use area administered by the US Army Corp of Engineers. Fishing, hiking, hunting, bird watching and wildlife viewing. Waterfowl concentration area. Ferruginous hawk, prairie falcon, Swainson’s hawk and ring-necked pheasant present. Wetland habitat.
  10. Windust Park (~RM 39, north): Approximately 54 acres, public day use and camping area administered by the US Army Corp of Engineers. Fishing, camping, bird watching and wildlife viewing. Waterfowl concentration area. Mule deer presence. Wetland habitat.

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Specific Geographic Areas of Concern – Maps and Descriptions

Figure 1: Snake River Ice Harbor Pool GRP specific geographic areas of concern.


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. 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, 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: SIH-GRP Cultural Resource Contacts

Contact Phone Email
Washington Department of Archaeology and Historic Preservation (360) 586-3080
US Army Corps of Engineers, Walla Walla District Office, Supervisory Archaeologist (509) 527-7274
Cowlitz Indian Tribe,
Cultural Resources Director
(360) 577-6962
Nez Perce Tribe,
Spill Responder and Water Quality
(208) 621-3893
Confederated Tribes of the
Umatilla Indian Reservation
(541) 276-4348
Warm Springs
Confederated Tribes
(541) 553-3257
Confederated Tribes of the
Yakama Indian Nation
(509) 865-5121 
Confederated Tribes of the
Colville Reservation, THPO
(509) 634-2695

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 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

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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. The Economic Resources at Risk PDF provides a list of economic resources for this GRP 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.

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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).

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.


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