Technical Papers

Modeling Ecosystem Integrity: Decision Tools for Prioritizing Stream Restoration

By W. Kleindl, L. Tear, C. Maney, P. Lawson, and B. LaVoie (Parametrix, Inc., USA)
Abstract:Stream restoration projects are increasing at unprecedented rates in the Puget Sound region. To allocate limited resources effectively, projects must be prioritized using best available science. To assist in prioritization of restoration projects in multiple drainages, an aquatic habitat assessment model was developed for Snohomish County, Washington, USA. We developed an ecologically based decision tool that was (1) appropriate in scale, cost-effective, and management focused, and (2) used regional reference data to compare sites and detect degraded conditions. The result was a multimetric habitat model called the “index of habitat integrity” (IHI). The development of the IHI included an assessment of over 60 different physical habitat attributes (e.g. woody debris, unstable banks) sampled in drainages that varied in degrees of human disturbance as measured by different land cover attributes (e.g. impervious area, forest cover). Physical attributes that changed in predictive ways with increased human influence provided meaningful indicators of habitat response to perturbation. Six habitat metrics, which met the qualification, were combined into the IHI model. The IHI model is used in conjunction with the benthic index of biotic integrity (B-IBI) as restoration prioritization decision tools.

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Sustainable river restoration in urban streams - using biological indicators to establish environmental flow targets in the Pacific Northwest

By J. L. Cassin & L. Tear (Parametrix, Inc., Kirkland, Washington, USA)
R. Fuerstenberg, K. Whiting, D. St. John, & B. Murray (King County Department of Natural Resources and Parks, Seattle, Washington, USA)
Abstract:Managing sustainable aquatic ecosystems requires restoration of ecological processes; such as the natural flow regime, as well as restoration of specific habitat structure and biological attributes. A general understanding of the ecological effects of altered flow regimes currently exists, but the lack of data on specific ecological responses to flow alteration has frequently hampered restoration efforts. In the Pacific Northwest, few attempts have been made to restore significant components of the natural flow regime, particularly in urban streams. To support river restoration and salmon recovery, King County is developing analytical tools for evaluating the ecological effects of altered flows on river and stream ecosystems. A first step in this multi-phased project is to use existing information to describe direct and indirect links between flow and ecosystem attributes. Based on a review of the literature, we identified candidate indicators of hydrologic alteration and ecosystem response that could be used to guide restoration. Using available biological and hydrologic data we tested candidate indicators to determine if flow-biology relationships could be identified and used as guidance in restoration programs.

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Restoring Biodiversity to Piñon-Juniper Woodlands

By Steven Albert, Nelson Luna, Roger Jensen and Larry Livingston
Abstract:Piñon and juniper woodlands of the American Southwest cover approximately 76,000 square miles (200,000 square kilometers) in six states, including approximately half of the 450,000-acre Zuni Indian Reservation in western New Mexico. Though piñon and juniper are native to the Reservation and the Colorado Plateau, the ecology of the woodlands and the distribution of these species have changed over the last century. Evidence suggests the trees were common on hillsides and rocky slopes, but did not regularly occur in valley bottoms and other flat, open areas. Over the course of the last several decades, however, piñon and juniper trees have become abundant (we would argue overabundant), particularly in these habitats, due to a variety of factors, including extensive livestock grazing, fire suppression, and drought. In many areas, piñon and juniper trees have become so dense that understory growth of shrubs, grasses, and forbs has been suppressed and is now either sparse or completely absent. We report on our experiments with thinning piñon and juniper to varying densities, and the impacts to plants and several taxa of wildlife. Overall, living plant biomass and plant diversity of the understory increased dramatically when piñon and juniper were heavily thinned. Big game were attracted to these areas, and small mammals increased for a short time. Bird use did not appear to differ in different density plots, though the plots may have been too small to detect meaningful differences. Using our results from these manipulation experiments, we have begun a program of pi˜on-juniper thinning across the Zuni Reservation.

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Monitoring Pilot-Scale Sediment Cap Asarco Smelter, Commencement Bay, Washington

Presented by Don Weitkamp, Ph.D.
Abstract:Evaluation of capping as a remedial action for contaminated sediments at the estuarine Asarco Site in Commencement Bay raised site-specific questions about the physical stability, chemical effectiveness, and biological productivity of a sediment cap. To address these issues two pilot caps were constructed in 1997 under agreement between the Environmental Protection Agency and Asarco. Capping had been selected as the preferred remedy to restore biological production and isolate high concentrations of metals from the biologically active environment of Commencement Bay. Capping is intended to isolate high chemical levels beneath the biologically active surface layer of a sediment cap. Most benthic infaunal activity occurs within the top 10 cm of marine sediments.

Pilot caps 30 and 60 cm thick were constructed to provide a site-specific evaluation of sediment cap effectiveness. The pilot cap plots were constructed adjacent to the Asarco ore dock where some of the highest metals concentrations and greatest biological effects occur at the offshore site. The pilot cap project was designed to evaluate nominal cap thicknesses of 30 cm (1 ft) and 60 cm (2 ft). Sandy sediment dredged from the outer edge of the Puyallup River Delta was released slowly from a bottom-dump barge to construct the two 450 m² cap plots at subtidal depths in the range of -20 to -40 ft MLLW.

Intensive monitoring over the following three years evaluated the physical, chemical, and biological characteristics of the pilot plots:

• Cap thickness was measured to determine if substantial erosion of the cap material has occurred.
• Core sampling and chemical analysis evaluated the effectiveness of the cap in isolating the high metals concentrations, and the surface recontamination by existing shoreline sources.
• Biological monitoring of benthic infauna evaluated the degree, rate and nature of biological repopulation of the new habitat provided by the cap material.

The following findings have resulted from the 24 and 36 months of monitoring at the constructed pilot cap:

• Following construction, cap thickness was found to be variable. The cap construction material contained a greater fine silt/clay fraction than anticipated. Clumping of the material resulted in a layer of uneven thickness covering the treatment areas. Initial cap thickness measurements were 13 to 42 cm in the 30 cm treatment area and 33 to 75 cm in the 60 cm area.
• General decreases in cap over 36 months have been small. Average cap thickness decreased by 0.6 cm in the 30 cm treatment area and 1.0 cm in the 60 cm area in the period from six to 24 months after cap placement. Cap thickness changes over this period have ranged from a loss of 6.0 cm to a gain of 10.1 cm.
• The pilot cap successfully isolated underlying sediment contamination. Core samples collected by divers showed little evidence of elevated metals concentrations throughout most of the cap thickness. Slight mixing of underlying sediment and cap material appears to have been limited to within 5 cm of the interface.
• Benthic invertebrate monitoring has shown rapid re-settlement and population of the cap material. The numbers of individuals and species present within one year are in the same range as those seen at reference locations, and they equal or exceed numbers present at the Asarco Site (Site) before capping. The numbers of individuals and species present after 2 years exceed those seen at reference locations.

In summary, results from the pilot project monitoring indicate that sediment capping will be an effective remedial action for targeted areas of the Site. General decreases in cap thickness have been minor, and metals concentrations within the cap material do not appear to be increasing. Monitoring has also shown rapid reestablishment of biological communities in the treatment areas. We expect a cap to effectively isolate metals from the environment and provide suitable habitat for healthy, indigenous marine life.

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Ten Years of Monitoring the First Estuarine Sediment Cap

Presented by Don Weitkamp, Ph.D.
Abstract:In 1988 contaminated sediment cap and new tideflat habitat were constructed in the shallow subtidal area adjacent to the Puyallup River delta at the Simpson Tacoma Kraft Mill, Tacoma, Washington. These tideflats were constructed as part of a project to remediate the contaminated subtidal sediments at the mill. Construction of new tideflats allowed estuarine habitat restoration to be incorporated into sediment remediation as a means to help build a functional new Puyallup River delta and partially satisfy natural resource damage claims.

The cap/tideflat habitat was constructed by filling the area of highly contaminated sediments with 5-20 ft of clean sand from the Puyallup River. Approximately 200,000 yd³ of sandy sediment from the Puyallup River channel was removed by a small hydraulic dredge and placed on the site of the contaminated sediments. This capping of the area of concern included additional material to bring the existing depths of -10 to -20 ft MLLW up to intertidal depths of -4 to +6 ft MLLW. Small boulders were placed randomly on the new intertidal area to increase the diversity of habitat. We have monitored the biological, chemical and physical conditions of this habitat for more than 10 years.

The constructed tideflat habitat has now been supporting biological functions for over ten years. This paper reviews the development of fauna and flora on the site and biological production during the caps first ten years.

Motile benthic invertebrates such as shore crabs and amphipods were observed moving onto the site during construction. The first monitoring event occurred one year following construction. By the end of the first year the number of benthic invertebrate species inhabiting the site had reached 100 taxa. This number increased to 191 taxa in year two. The diversity of benthic invertebrates has remained in the general range of 200-225 taxa in recent years. The abundance of benthic invertebrates has followed a similar trend.

Our monitoring has also shown that the production of epibenthic invertebrates and algae has been substantial on the constructed tideflats. In comparison to reference areas within Commencement Bay, the constructed habitat appears to equal natural production in both number of species present and abundance of individuals living in the cap habitat.

The habitat continues to change in natural ways as anticipated by our design. Some areas have increased or decreased in elevation. A quiescent area has accumulated fine sediments from the Puyallup River's sediment load as anticipated. We expect this habitat to grow and change with time as a part of the newly forming Puyallup River delta.

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Behavior of Resident Fish Relative to TDG Supersaturation in the Lower Clark Fork River

Submitted for Publication by Don Weitkamp, Ph.D., Robert D. Sullivan, Parametrix; Tim Swant, and Joe DosSantos, Avista Corp. Abstract:Behavior of resident fish exposed to total dissolved gas (TDG) supersaturation in Pacific Northwest rivers greatly influences the degree of supersaturation these fish actually experience. Because TDG supersaturation is a physical condition that is moderated by hydrostatic pressure, the depths occupied by fish during supersaturation conditions determine the biological effects experienced by members of the exposed population. Equipping fish with depth sensing radio tags documented that many of the fish spend sufficient time at depths of several meters or greater where they are not exposed to TDG supersaturation. These depths also provide an opportunity to recover from short-term exposure to supersaturation experienced by the fish during the periods they occupy shallower depths. Most species tagged had median and average depth distributions of about two meters or greater providing compensation for TDG supersaturation in the range of 120% of saturation or greater. Tagged rainbow trout generally remained in the river for only brief periods before returning to Lake Pend Oreille or tributaries to the lower Clark Fork River, where they were no longer exposed to TDG supersaturation.

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Gas Bubble Disease in Resident Fish of the Lower Clark Fork River

Submitted for Publication by Don Weitkamp, Ph.D., Robert D. Sullivan, Parametrix; Tim Swant, and Joe DosSantos, Avista Corp. Abstract:Gas bubble disease (GBD) occurs in resident fish of the lower Clark Fork River exposed to total dissolved gas (TDG) supersaturation produced by spill at upstream hydroelectric projects. This report describes the incidence and severity of GBD observed in fish routinely collected by electrofishing and other techniques during periods of high supersaturation from 1997 to 2000. These data include GBD observations for 1997, a year of extremely high runoff resulting in TDG levels approaching 150% of saturation, and 1999, a year of moderately high TDG levels (typically 120-130% of saturation). Although electrofishing only samples that portion of the fish populations present near the river surface (upper 2m) in a deep stream (3-25m) like the lower Clark Fork, the observed incidence and severity of GBD was substantially lower than anticipated for the levels of TDG measured. It appears that the majority of fish are spending sufficient time at depths that avoid or mediate both the incidence and severity of GBD when TDG supersaturation is in the range of 120-130% of saturation. Fish also have access to a number of tributaries that have little or no supersaturation, and to Lake Pend Oreille where fish commonly occupy depths providing hydrostatic compensation that eliminates exposure to supersaturation.

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Controlling Total Dissolved Gas - Lower Clark Fork River Dams

Submitted for Publication by Robert D. Sullivan, Don Weitkamp, Ph.D., Parametrix; Tim Swant, and Joe DosSantos, Avista Corp. Abstract:Studies indicate that changing the normal spill gate configurations used at the lower Clark Fork River hydroelectric projects can substantially reduce downstream total dissolved gas (TDG) supersaturation. Investigation of operational procedures at Noxon Rapids and Cabinet Gorge Dams between 1997 and 2001 demonstrated how various spill gate combinations, and other factors at the two dams influence TDG levels. Controlled spill tests at Noxon Rapids Dam indicated that spilling through gates over the central portion of the spillway could reduce TDG levels by 6% to 12% of saturation as compared to spill through the end gates equipped with flip buckets. It appears the combination of greater air entrainment with the flip buckets together with entrainment of air bubbles in the powerhouse discharge resulted in the higher TDG levels when the end gate closest to the powerhouse was used. At Cabinet Gorge Dam controlled spill tests demonstrated TDG levels could be reduced by as much as 13% of saturation using a different gate combinations. It appears gates near the powerhouse and over the deeper portion of the stilling basin allow greater entrainment of bubbles into the powerhouse discharge resulting in higher TDG levels. These observations demonstrate the unique properties of each dam that lead to higher or lower TDG levels downstream.

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Stormwater Filtration Media Testing for Metals Removal and Toxicity Reduction

by Scott A. Tobiason, Port of Seattle; Linda R. J. Logan, Parametrix; Curtis Nickerson, Taylor Associates, Seattle, WA Abstract:The Port of Seattle tested four filtration media in controlled laboratory experiments to determine their effectiveness for concurrent metals removal and toxicity abatement in synthetic stormwater. Media tested included commercially available leaf compost (CSF®) media, a zeolite/perlite mix, and a polyamine sponge, as well as the recently developed citric acid modified soybean hull media. Toxicity was assessed using acute Ceriodaphnia dubia (48 hr) bioassays.

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Estuarine Habitat Used by Young Salmon -- an Annotated Bibliography

by Don Weitkamp, Ph.D.

Introduction:This annotated bibliography is a compilation of literature dealing with various biological aspects of juvenile anadromous salmon as they rear in and migrate through estuaries of the north Pacific. The bibliography concentrates on those species that are primarily anadromous (chinook, chum, pink, sockeye and steelhead) because of the substantial information available for these species. Other species that have some anadromous populations such as cutthroat trout and bull trout are not covered by this bibliography.

The bibliography covers reports that provide information on the shoreline habitats used by young salmon as they pass from rivers into the marine environment of the Pacific Northwest. It attempts to identify the: