Scappoose River population .or.us



Lower Columbia Coho Evolutionarily Significant Unit

Scappoose River Population

Table of Contents Page

Geographical Overview 2

W/LC TRT Population Assessment 3

Habitat Complexity 4

Fish Passage 6

Riparian Condition 7

Water Quality 9

Water Quantity 12

Substrate 13

Hatchery 14

Works Cited 14

Geographical Overview

The Scappoose Bay watershed is a fifth field watershed located in the northwest corner of Oregon. The Scappoose Bay watershed drains approximately 133 sq. mi. of land. The Scappoose Bay watershed historically supported four of six species of salmon found in the Pacific Northwest. The Scappoose Bay watershed has a broad range of channel types in terms of size (flow accumulation), confinement, gradient, and estuarine influence (Table 1). Twelve of the 24 potential channel type combinations occur. The upper watershed is dominated by high gradient, confined, and small streams. The mainstem reaches of the major streams in the valleys are generally low gradient and unconfined, but with some confined reaches. The lower watershed is dominated by low gradient, unconfined estuarine channels of various sizes. Many of these smaller estuarine streams are channelized (DEA 2000).

Table 1. Stream Miles and Percent of Total Stream Miles for Each Channel Classification in the Scappoose Bay Watershed (DEA 2000).

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W/LC TRT Scappoose Population Assessment

Details of the W/LC TRT evaluation method are described in the Interim Report on Viability Criteria for Willamette and Lower Columbia Basin Pacific Salmonids (2003). This document is available at the following website: .

Following is a brief summary of the evaluation method. For the evaluation, populations were ranked for absolute extinction risk on a scale of 0 to 4. The extinction risks associated with each value on the 0–4 scale are summarized below.

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It is important to note that the persistence categories (0–4) do not represent a linear scale. For example, the persistence probability associated with category 0 has a much greater range (0– 40%) than category 4 (> 99%). Extinction risk is the complement of persistence probability (i.e., extinction risk = 1 – persistence probability). To estimate population extinction risk, four key attributes were evaluated: abundance and productivity, diversity, spatial structure, and habitat. A fifth population attribute, JOM growth rate, is part of the W/LC TRT viability criteria, but did not have much impact on the population evaluations due to lack of data. The four main population attributes were evaluated on the same 0–4 risk scale. To obtain the overall population score, individual population attribute scores were integrated using a simple weighted mean; the abundance and productivity scores were weighted at twice the other scores (McElhany, et al. 2004).

The W/LC TRT population status evaluations were based on a set of data atlases compiled by the Northwest Fisheries Science Center in 2003.

Table 2. W/LC TRT Scappoose River Viability Assessment (McElhany, et al.

2004).

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Weighted average: 1.11

Productivity and abundance: Recent improvements in escapement (up to the low 100s) follow a number of years of escapements of 0 or near 0. Reliance on a single peak index count in many years introduces considerable uncertainty into the evaluation. TRT members also noted that there have been few direct hatchery introductions into this area in recent years.

JOM: Not rated.

Diversity: Small population size could have created a genetic bottleneck or made the population susceptible to introgression by stray hatchery fish. Some TRT members focused on the absence of recent hatchery introductions.

Habitat: Conditions are moderately to severely impaired. Agriculture and residential and urban development correlate strongly with severely impaired areas.

Spatial structure: Numerous small blockages (tide gates, culverts) may influence access to smaller tributaries and side channels. Patches of poor habitat could also affect coho salmon distribution (McElhany, et al. 2004).

Habitat Complexity

Major impacts in the Scappoose watershed over the past 150 years are the loss of LWD and forested riparian zones due to forestry activities and the subsequent delivery of fine sediment to downstream areas (DEA 2000). Riparian zones along most tributaries have been converted from old growth forests to clear-cuts with and without riparian buffers by decades of timber harvests. Most of the tributaries in the upper watershed that are classified as grass/forb were clear-cut within the five years preceding the watershed assessment (1995-2000) and were not yet dominated by shrubs or young trees.

Low in the system, mainstem streams run through the Scappoose prairie and most of these channels have retained their basic meandering form (DEA 2000). However, water diversions, loss of coniferous riparian zones and large wood, increased peak flows that destabilize channels and cause bed scour and bank erosion, and increased sediment that fills pools and clogs spawning gravels have probably degraded habitat used historically by coho salmon (DEA 2000).

The lowland floodplain next to Multnomah Channel has been extensively modified by channelization and diking (DEA 2000) for flood control measures and farming. The south end of Scappoose Bay, on the east side of the watershed, is one location where historical wetlands and channels appear to remain relatively intact. The area represents the only remaining large tract of Columbia River floodplain habitat that was not diked, drained, and converted to farmland in the lower Scappoose watershed. The area includes the mainstem of Scappoose Creek, numerous tidal sloughs and ponds, and extensive beds of wapato plants. It provides habitat for a diversity of fish and wildlife, including rearing habitat for salmonids. The two-mile reach of Scappoose Creek downstream of the junction of North and South Scappoose creeks is known to have been spawning grounds for a chinook population (Willis et al. 1960, cited in DEA 2000) and was probably used by chum salmon as well. Most of the area is part of the Malarkey Ranch property.

On the west side of the watershed, most of the floodplain is still mapped as wetland, but it has been converted to agricultural uses. Reaches in Salmon, Sierkes, North Scappoose, and Raymond creeks that were surveyed by ODFW in 1999 generally had low levels of LWD and relatively low shade cover and few pools (DEA 2000).

Milton Creek was the largest producer of chum salmon in the watershed with a total spawning run of about 200 fish per year (Willis et al. 1960). However, the location of the spawning grounds within Milton Creek is unknown. At least two splash dams were used on Milton Creek, and annual log drives of as much as 3 million board feet of timber occurred there between 1846 and 1915, which cut the banks and widened the channel in the low lands downstream (DEA 2000).

Table 3. An Assessment of the Amount of Change from Historic to Existing

Conditions for Selected Habitat Parameters for Each Stream Habitat Type in the Scappoose Bay Watershed (DEA 2000).

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Very few areas remain in the Scappoose Bay watershed that would appear to qualify as high quality habitat, or refugia, for salmonids. Fish habitats have been extensively degraded by over 150 years of forestry, agricultural, and residential and commercial development activities. Most of the watershed is in private ownership, with valleys extensively used for agriculture and residential and commercial development, and hills used for industrial forestry. Less than two acres of old growth forest remain in the 133 sq. mi. watershed. Road density is also high throughout the watershed (DEA 2000).

Table 4. Summary of Life Stages and VSP Parameters Affected.

|Life |Egg to Parr |Parr to Smolt |Smolt to Adult |

|Stages | | | |

|Affected | | | |

| | | | |

| | | | |

| |

|VSP Parameters |Abundance |Productivity |Diversity |Spatial Structure |

|Affected | | | | |

| | | | | |

| |X |X |X |X |

Fish Passage

Fish populations can be significantly limited if they lose access to key habitat areas. Potential effects from the loss of fish passage include loss of genetic diversity by isolation of reaches, loss of range for juvenile anadromous and resident fish and loss of resident fish from extreme flood or drought events.

Given the high road density and large number of road crossings, it is likely that culverts are barriers to fish migration in the Scappoose watershed (DEA 2000). Two water supply dams owned by the City of Scappoose on Lazy Creek and South Scappoose Creek may block some salmonids. A third dam on Gourlay Creek may bock about two miles of upstream habitat but was also not known to be used by chum salmon. At least two old dams on Milton Creek may block some species. The tide gate at the north end of Joy Creek (in the south portion of the watershed) may block fish access during high flows.

There are 270 road/stream crossings, dams, and other anthropogenic barriers in the Scappoose Bay watershed. Of the 270 road/stream crossings dams, and other anthropogenic barriers surveyed, 131 did not meet fish passage criteria – see Table 5.

Table 5. Summary of Fish Passage Barrier Surveys (DEA 2001).

|Crossing Type |No. Surveyed |No. Barriers |Percent Barriers |

|Dam |13 |13 |100 |

|Round Culvert |140 |111 |79 |

|Box Culvert |8 |5 |63 |

|Bridge |105 |0 |0 |

|Other |4 |2 |50 |

|Total |270 |131 |49 |

Table 6. An Assessment of the Amount of Change from Historic to Existing

Conditions for Selected Habitat Parameters for Each Stream Habitat Type in the Scappoose Bay Watershed (DEA 2000).

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Table 7. Summary of Life Stages and VSP Parameters Affected.

|Life |Egg to Parr |Parr to Smolt |Smolt to Adult |

|Stages | | | |

|Affected | | | |

| | | | |

| | | | |

| |

|VSP Parameters |Abundance |Productivity |Diversity |Spatial Structure |

|Affected | | | | |

| | | | | |

| |X |X | |X |

Riparian Condition

Major impacts in the Scappoose watershed over the past 150 years are the loss of LWD and forested riparian zones due to forestry activities and the subsequent delivery of fine sediment to downstream areas (DEA 2000). Riparian zones along most tributaries have been converted from old growth forests to clear-cuts with and without riparian buffers by decades of timber harvests. Most of the tributaries in the upper watershed that are classified as grass/forb were clear-cut within the five years preceding the watershed assessment (1995-2000) and were not yet dominated by shrubs or young trees.

Low in the system, mainstem streams run through the Scappoose prairie and most of these channels have retained their basic meandering form (DEA 2000). However, water diversions, loss of coniferous riparian zones and large wood, increased peak flows that destabilize channels and cause bed scour and bank erosion, and increased sediment that fills pools and clogs spawning gravels have probably degraded habitat used historically by chum salmon (DEA 2000).

Table 8. Physical Habitat Condition Ratings for Selected Riparian and LWD Habitat Parameters (DEA 2000).

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The current riparian conditions represent a major shift from historical conditions under which salmon evolved in the watershed. Historically, most of the watershed was dominated by mature and old growth coniferous forest in the hills to the west, by oak savanna in the prairie, and by a variety of shrub, deciduous forested and open-water wetlands in the Columbia River floodplain. Most of the riparian zones in the watershed are now in relatively poor condition.

The surveyed reaches generally have low levels of LWD and relatively low shade cover and few pools. Much of the large wood recruitment, shade, bank protection, and other functions historically provided by old growth forest riparian zones have been reduced by agricultural, residential, and forestry uses.

Table 9. Summary of Life Stages and VSP Parameters Affected.

|Life |Egg to Parr |Parr to Smolt |Smolt to Adult |

|Stages | | | |

|Affected | | | |

| | | | |

| | | | |

| |

|VSP Parameters |Abundance |Productivity |Diversity |Spatial Structure |

|Affected | | | | |

| | | | | |

| |X |X |X |X |

Water Quality

Very little water quality monitoring has been conducted in the watershed. Reaches monitored in 1998 (including one site in the upper reaches of Milton Creek) all showed temperatures exceeding the 55 degree F maximum average temperature standard (DEA 2000). The water quality of Scappoose Bay appears to have been affected by industrial sources of pollution in the past. In 1960, the Fish Commission of Oregon (Willis et al. 1960 cited in DEA 2000) reported on a fish kill and suspected causes. These were discharges from a local paper mill to Multnomah Channel, which sometimes backed up into Scappoose Bay with the tide, and from a gypsum wallboard and a wood preserving plant, directly to Scappoose Bay. In December 1956, sporadic rains attracted fall-run salmon (which, based on timing, could have included chum) into the bay, but subsequent dry periods appear to have caused lethal conditions “when materials from polluting effluents became concentrated.” Since then, Oregon’s Department of Environmental Quality has issued seven National Pollutant Discharge Elimination System permits for operations in the watershed, including two municipal sewage treatment plants and a veneer plant and pulp mill. According to DEA (2000), it appears that water quality impacts from industrial discharges have been greatly reduced since the fish kills in Scappoose Bay in the 1950s. Stormwater outfall information was available only from the City of Scappoose, where 134 of 211 storm drains flow directly from the streets into Scappoose Creek.

The Lower Columbia River Bi-State Program included one sampling station in Scappoose Bay. Results show that these samples, collected in 1993, exceeded state, federal, or recommended threshold levels for the water quality concerns listed below, as well as for temperature requirements of salmonids (Tetra Tech 1996 as cited in DEA 2000):

Water Sampling

• Fecal coliform

• Temperature

• Clorophyll A

• Total recoverable iron

• Total recoverable lead

• Total recoverable aluminum

Sediment Sampling

• Arsenic

• Cadmium

• Chromium

• Copper

• Iron

• Nickel

• p,p-DDD (pesticide)

Tissue Sampling

• Total polychlorinated biphenols (PCBs)

Table 10. Water Temperature Measurements in Scappoose Bay River Miles 1 and 2 (DEA 2000).

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Temperature criteria for waters Oregon are 13°C (55.4°F) for spawning, 16°C (60.8°F) for core cold water habitat, and 18°C (64.4°F) for rearing and migration.

Table 11. Summary of Life Stages and VSP Parameters Affected.

|Life |Egg to Parr |Parr to Smolt |Smolt to Adult |

|Stages | | | |

|Affected | | | |

| | | | |

| | | | |

| |

|VSP Parameters |Abundance |Productivity |Diversity |Spatial Structure |

|Affected | | | | |

| | | | | |

| |X |X |X |X |

Water Quantity

Limited instream flow data is available for the Scappoose watershed (DEA 2000). The City of Scappoose operates three storage dams on Gourlay, Lazy, and South Scappoose creeks, respectively, as the City’s municipal water supply (DEA 2000). The City of St. Helens owns an inactive dam on Salmonberry Creek, a tributary to Milton Creek, and currently obtains water from two groundwater wells and a Ranby collector (the latter is a drainage pipe located about 20 feet under the bed of the Columbia River that collects groundwater). Irrigation water rights and irrigated acres are concentrated in the lowland floodplain (dikelands) and Scappoose prairie. The Scappoose Drainage District maintains a series of water pumps that pump water out of the canals and streams of the dikelands for flood control.

Floodplains cover most of the area east of Highway 30. Much of the historical floodplain is protected by the Multnomah Channel dike, which has shifted the flood frequency from 100 to 500 years. The 100-year floodplain extends upstream along most of the stream valleys. Historical information suggests that most floodplains and their habitats were converted to agricultural uses in the late 1800s and early 1900s. Dams constructed in the Willamette and Columbia rivers further reduced flooding. Formation of the Scappoose Drainage District in 1922 and construction of drainage ditches, pumping stations, and the Multnomah Channel dikes over the next several years had the largest effect on reducing flood frequency in the lowlands.

Table 12. Summary of Life Stages and VSP Parameters Affected.

|Life |Egg to Parr |Parr to Smolt |Smolt to Adult |

|Stages | | | |

|Affected | | | |

| | | | |

| | | | |

| |

|VSP Parameters |Abundance |Productivity |Diversity |Spatial Structure |

|Affected | | | | |

| | | | | |

| |X |X |X |X |

Substrate

Gravel beds are important channel features because they provide spawning and incubating areas for salmonids. There is limited data on substrate quality and quantity in the Scappoose Bay watershed. Table 13 shows percent of gravels per reach surveyed.

Table 13. In-Stream Habitat Parameters and Condition Ratings for Stream Reaches Surveyed in the Scappoose Bay Watershed (DEA 2000).

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Table 14. Summary of Life Stages and VSP Parameters Affected.

|Life |Egg to Parr |Parr to Smolt |Smolt to Adult |

|Stages | | | |

|Affected | | | |

| | | | |

| | | | |

| |

|VSP Parameters |Abundance |Productivity |Diversity |Spatial Structure |

|Affected | | | | |

| | | | | |

| |X |X |X |X |

Hatchery

The record of hatchery stocking obtained from ODFW indicates that hatchery coho and

steelhead were planted extensively in the major streams in the watershed. Coho fry

and fingerlings and steelhead fry, fingerling, and smolts were released into the North

Scappoose Creek, South Scappoose Creek, Honeyman Creek, and Milton Creek between 1975 and 1990. The brood stock for coho included Sandy River, Cowlitz River, Klatskanine and Tanner Creek stock. The brood stock for steelhead was from Big Creek. The Salmon Trout Enhancement Program (STEP), organized by ODFW, released hatchbox steelhead into Scappoose Creek from 1983 to 1990. Hatchery stocking was discontinued by ODFW in 1990 due to their concern regarding the adverse effects of hatchery fish stocks on native stocks (DEA 2000).

Works Cited

DEA (David Evans and Associates, Inc.). 2000. Scappoose Bay watershed assessment. Prepared for Scappoose Bay Watershed Council, Scappoose, OR.

DEA (David Evans and Associates, Inc.). 2001. A Comprehensive Assessment of Fish Passage Barriers in the Scappoose Bay Watershed.

McElhany, P., T. Backman, C. Busack, S. Kolmes, J. Myers, D. Rawding, A. Steel, C. Steward, T. Whitesel, and C. Willis. 2004. Status evaluation of salmon and steelhead populations in the Willamette and lower Columbia basins. Willamette/Lower Columbia Technical Recovery Team. National Marine Fisheries Service, Northwest Fisheries Science Center.

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