Willamette River Research Articles

Efficacy of Translators for Establishing Mercury Total Maximum Daily Loads

ABSTRACT In Oregon's Willamette River, methylmercury levels in fish triggered health advisories and the need for a mercury Total Maximum Daily Load (TMDL). A translator was used to relate surface water total mercury (CTHg) to dissolved methylmercury concentrations (CDMeHg). The USEPA's Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury (SERAFM) was used to elucidate the annual relationship between mercury loads, CTHg, and CDMeHg, to investigate whether CTHg is a reasonable predictor for CDMeHg, and to consider how load reductions may be affected by the differing annual trajectories of total and methylmercury concentrations. Modeling and observations suggest that CTHg and CDMeHg are not directly proportional, that CTHg is an inconsistent predictor of CDMeHg, that a single point estimate translator could easily misjudge their relationship, and that CDMeHg may be more responsive to environmental factors than to load alone. While a translator is convenient for relating CTHg and CDMeHg for regulatory purposes, it may not, due to environmental factors unrelated to loading, be the most efficacious means for this purpose. TMDLs relying on a translator are advised to conduct co-located total and methylmercury sampling with sufficient frequency to provide information on the watershed-specific annual relationship between total mercury and methylmercury.

Climate change impacts on spatial patterns in drought risk in the Willamette River Basin, Oregon, USA

Climate change is likely to lead more frequent droughts in the Pacific Northwest (PNW) of America. Rising air temperature will reduce winter snowfall and increase earlier snowmelt, subsequently reducing summer flows. Longer crop-growing season caused by higher temperatures will lead to increases in evapotranspiration and irrigation water demand, which could exacerbate drought damage. However, the impacts of climate change on drought risk will vary over space and time. Thus, spatially explicit drought assessment can help water resource managers and planners to better cope with risk. This study seeks to identify possible drought-vulnerable regions in the Willamette River Basin of the PNW. In order to estimate drought risk in a spatially explicit way, relative Standardized Precipitation Index (rSPI) and relative Standardized Runoff Index (rSRI) were employed. Statistically downscaled climate simulations forcing two greenhouse gas emission scenarios, A1B and B1, were used to investigate the possible changes in drought frequency with 3-, 6-, 12-, and 24-month time scales. The results of rSPI and rSRI showed an increase in the short-term frequency of drought due to decreases in summer precipitation and snowmelt. However, long-term drought showed no change or a slight decreasing pattern due to increases in winter precipitation and runoff. According to the local index of spatial autocorrelation analysis, the Willamette Valley region was more vulnerable (hot spot) to drought risk than the mountainous regions of the Western Cascades and the High Cascades (cold spot). Although the hydrology of the Western Cascades and the High Cascades will be affected by climate change, these regions will remain relatively water-rich. This suggests that improving the water transfer system could be a reasonable climate adaptation option. Additionally, these results showed that the spatial patterns of drought risk change were affected by drought indices, such that appropriate drought index selection will be important in future studies of climate impacts on spatial drought risk.

Using Legacy Data to Relate Biological Condition to Cumulative Aquatic Toxicity in the Willamette River Basin (Oregon, USA)

In the Willamette River Basin (Oregon, USA), various residential, municipal, industrial, and agricultural activities produce physical, biological, and chemical stressors that may impinge on the basin's aquatic ecosystems. For > 30 years, numerous water-quality and biological-condition data have been accumulated by often disparate monitoring programs. This diagnostic analysis explored whether these legacy data could be used to correlate the presence of chemical stressors with biological condition impacts with the understanding that association is not necessarily causation. Other natural or anthropogenic stressors that may also impact biological conditions were not considered in this study. Acute-toxicity indices were calculated separately for trace metals and organic chemicals detected in surface waters between 1994 and 2010 and then compared with land-use metrics and vertebrate- and invertebrate-assemblage indices from surveys conducted basin-wide during this same period. Half of the possible relations between land use, biological condition, and toxicity were statistically significant at p ≤ 0.10. These results suggest that conditions for aquatic receptors improve either as agricultural or urban land decreases or as forested land increases and that chemical mixtures (primarily involving pesticides) may have impacted components of the basin's aquatic ecosystems. There may be a need for strengthened chemical-management practices on agricultural and urban lands and for maintaining undisturbed forested land to limit chemical migration into adjacent waters. Although these results indicate some utility for legacy data, they also suggest that a more defensible assessment of chemical stressors requires a program specifically designed for that purpose.

Tracking of small vessels with passive acoustic sensors

This paper introduces a small boat vessel tracking method in marine environment using autonomous, low-complexity acoustic sensors. A cross-correlation of time series between sensors generates a coarse localization, and an application of the extended Kalman filter (EKF) gives the vessel track. Since each sensor has a local clock that operates asynchronously, the time series received by multiple sensors are first synchronized with one another by measuring a sequence of impulses played at the beginning of the recording. The algorithm detects a moving boat by the increase in the broadband sound level and confirms it by extracting the amplitudes at harmonic frequencies due to the propeller movement. To calculate the time delay of arrival, the boat-present signals are divided into small segments that are cross-correlated with signals received by other sensors. Thresholding and clustering are introduced to extract multiple tracks from the cross-correlation. The EKF is trained using the estimated time delays to provide the vessel track. The algorithm has been successful with Bellhop simulated boat signals and field data collected on the Willamette River and Columbia River in Oregon. Limiting factors such as network topology and sensor movement during deployment are also investigated. [Work sponsored by the Nature Conservancy.]

Polycyclic Aromatic Hydrocarbons and Risk to Threatened and Endangered Chinook Salmon in the Lower Columbia River Estuary

Polycyclic aromatic hydrocarbons (PAHs), derived from oil and fuel combustion, are ubiquitous nonpoint source pollutants that can have a number of detrimental effects on fish and wildlife. In this study, we monitored PAH exposure in outmigrant juvenile Chinook salmon from the Lower Columbia River to evaluate the risk that these contaminants might pose to the health and recovery of threatened and endangered salmonids. Juvenile Chinook salmon (Oncorhynchus tshawytscha) were collected by beach seine from five sites in the Lower Columbia River from Bonneville Dam to the mouth of the estuary (Warrendale, the Willamette-Columbia Confluence, Columbia City, Beaver Army Terminal, and Point Adams) and from a site in the Lower Willamette near downtown Portland (Morrison Street Bridge). Sediment samples were also collected at the same sites. Concentrations of PAHs in sediment samples were relatively low at all sites with average total PAH concentrations <1000 ng/g dry weight (wt.). However, we found PAHs in stomach contents of salmon from all sites at concentrations ranging from <100 to >10,000 ng/g wet wt. Metabolites of low and high molecular-weight PAHs were also detected in bile of salmon from all sites; for metabolites fluorescing at phenanthrene (PHN) wavelengths, concentrations ranged from 1.1 to 6.0 μg/mg bile protein. Levels of PAHs in stomach contents and PAH metabolites in bile were highest in salmon from the Morrison Street Bridge site in Portland and the Willamette-Columbia Confluence, Columbia City, and Beaver Army Terminal sites. Mean PAH concentrations measured in some stomach content samples from the Columbia City, Beaver Army Terminal, and Morrison Street Bridge sites were near the threshold concentration (approximately 7200-7600 ng/g wet wt.) associated with variability and immune dysfunction in juvenile salmonids (Meador et al., Can J Fish Aquat Sci 63:2364-2376, 2006; Bravo et al., Environ Toxicol Chem 30:704-714, 2011). Mean levels of biliary fluorescent aromatic compounds (FACs)-PHN in juvenile Chinook collected at the Morrison Street Bridge site in Portland, at the Confluence and Columbia City sites, and at the Beaver Army Terminal site were at or above a threshold effect concentration of 2 μg/mg protein for FACs-PHN linked to growth impairment, altered energetics, and reproductive effects (Meador et al., Environ Toxicol Chem 27(4):845-853, 2008). These findings suggest that PAHs in the food chain are a potential source of injury to juvenile salmon in the Lower Columbia and Lower Willamette rivers.

Human Influence on the Spatial Structure of Threatened Pacific Salmon Metapopulations

To remain viable, populations must be resilient to both natural and human-caused environmental changes. We evaluated anthropogenic effects on spatial connections among populations of Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) (designated as threatened under the U.S. Endangered Species Act) in the lower Columbia and Willamette rivers. For several anthropogenic-effects scenarios, we used graph theory to characterize the spatial relation among populations. We plotted variance in population size against connectivity among populations. In our scenarios, reduced habitat quality decreased the size of populations and hydropower dams on rivers led to the extirpation of several populations, both of which decreased connectivity. Operation of fish hatcheries increased connectivity among populations and led to patchy or panmictic populations. On the basis of our results, we believe recolonization of the upper Cowlitz River by fall and spring Chinook and winter steelhead would best restore metapopulation structure to near-historical conditions. Extant populations that would best conserve connectivity would be those inhabiting the Molalla (spring Chinook), lower Cowlitz, or Clackamas (fall Chinook) rivers and the south Santiam (winter steelhead) and north fork Lewis rivers (summer steelhead). Populations in these rivers were putative sources; however, they were not always the most abundant or centrally located populations. This result would not have been obvious if we had not considered relations among populations in a metapopulation context. Our results suggest that dispersal rate strongly controls interactions among the populations that comprise salmon metapopulations. Thus, monitoring efforts could lead to understanding of the true rates at which wild and hatchery fish disperse. Our application of graph theory allowed us to visualize how metapopulation structure might respond to human activity. The method could be easily extended to evaluations of anthropogenic effects on other stream-dwelling populations and communities and could help prioritize among competing conservation measures.

Estimating risk at a Superfund site using passive sampling devices as biological surrogates in human health risk models

Passive sampling devices (PSDs) sequester the freely dissolved fraction of lipophilic contaminants, mimicking passive chemical uptake and accumulation by biomembranes and lipid tissues. Public Health Assessments that inform the public about health risks from exposure to contaminants through consumption of resident fish are generally based on tissue data, which can be difficult to obtain and requires destructive sampling. The purpose of this study is to apply PSD data in a Public Health Assessment to demonstrate that PSDs can be used as a biological surrogate to evaluate potential human health risks and elucidate spatio-temporal variations in risk. PSDs were used to measure polycyclic aromatic hydrocarbons (PAHs) in the Willamette River; upriver, downriver and within the Portland Harbor Superfund megasite for 3 years during wet and dry seasons. Based on an existing Public Health Assessment for this area, concentrations of PAHs in PSDs were substituted for fish tissue concentrations. PSD measured PAH concentrations captured the magnitude, range and variability of PAH concentrations reported for fish/shellfish from Portland Harbor. Using PSD results in place of fish data revealed an unacceptable risk level for cancer in all seasons but no unacceptable risk for non-cancer endpoints. Estimated cancer risk varied by several orders of magnitude based on season and location. Sites near coal tar contamination demonstrated the highest risk, particularly during the dry season and remediation activities. Incorporating PSD data into Public Health Assessments provides specific spatial and temporal contaminant exposure information that can assist public health professionals in evaluating human health risks.

Size at Release, Size‐Selective Mortality, and Age of Maturity of Willamette River Hatchery Yearling Chinook Salmon

AbstractWe analyzed scales from returning Willamette River yearling Chinook salmon Oncorhynchus tshawytscha to explore the effects of size at release on subsequent adult returns. We tested the hypothesis that survival to adulthood is independent of size at ocean entry for yearling Chinook salmon. Significant size‐selective mortality, indicated by a larger size at ocean entry among surviving adults than among all released juveniles, was observed for Chinook salmon released in 2002–2004 but not for those released in 2005. Juvenile Chinook salmon released in 2002–2004 that entered the ocean at less than 150 mm in fork length were underrepresented in the returning adult populations. We also investigated the relationships between age at maturity and size at ocean entry, timing of release, circulus spacing, and size at the end of the first ocean year. We observed significant differences in fork length at the end of the first ocean winter among returning age‐4, ‐5, and ‐6 Chinook salmon; the younger returning fish were larger after their first year of ocean growth. Fork length at ocean entry and average first‐ocean‐year circulus spacing were significantly greater for age‐4 than for age‐5 and age‐6 Chinook salmon but were similar for age‐5 and age‐6 fish. Our analyses indicate that yearling Chinook salmon may experience size‐selective mortality, although the relationship between the intensity of size‐selective mortality and smolt‐to‐adult survival remains unclear.

PLANT SUCCESSION AFTER HYDROLOGIC DISTURBANCE: INFERENCES FROM CONTEMPORARY VEGETATION ON A CHRONOSEQUENCE OF BARS, WILLAMETTE RIVER, OREGON, USA

ABSTRACTHistoric unconstrained, unregulated streamflow along the upper Willamette River, Oregon produced a floodplain of coalescent bars supporting a mosaic of vegetation patches. We sampled 42 bars and adjacent floodplain that formed recently to &gt;64 years ago in four &gt;1‐km‐long reaches to assess differences in vegetation and bar characteristics. Bar disturbance and environmental factors (streamflow, precipitation and regional climate indices) were estimated within six aerial photo intervals between 1936 and 2006. Black cottonwood (Populus balsamifera ssp. trichocarpa) and Salix species rapidly colonized new and disturbed bars, and independent estimates of bar and vegetation age were positively correlated across photo intervals (R2 = 0.95). Overstory communities varied with age: Populus–Salix spp. on gravel bars (trees aged 9–16 years [interquartile range]), Populus on islands (24–45 years), Populus/Acer–Fraxinus on islands coalesced to floodplain (49–72 years) and Acer–Populus on adjacent floodplain forested since 1936 (64–102 years). Meanwhile, bar height, silt/clay fraction, overstory basal area and community wetland prevalence index (WPI) increased. We identified a common but distinct Pacific willow (Salix lucida ssp. lasiandra) community (30–43 years) associated with back channels and island tails. Six understory communities varied by age and by WPI within age strata; in these communities 55–75% of total cover was introduced species, predominantly Phalaris arundinacea and Rubus armeniacus. Vegetation resets occurred in all photo intervals and affected 31% of sampled bars. Mean bar disturbance rate, Q1.5 frequency, precipitation and the Pacific Decadal Oscillation index followed cyclic trends across photo intervals whereas Qmax decreased linearly and relatively fewer, younger bars were disturbed. Results suggest that Populus patch initiation is ongoing but channel stability may be hindering the long‐term self‐sustainability of plant communities associated with the upper Willamette's historic shifting habitat mosaic. Published in 2011 by John Wiley &amp; Sons, Ltd.

Global‐scale river routing—an efficient time‐delay algorithm based on HydroSHEDS high‐resolution hydrography

AbstractCoupling of global hydrologic and atmospheric models is difficult because of the highly nonlinear hydrological processes to be integrated at large scales. Aggregation of high‐resolution data into low‐resolution spatial distribution functions is one way to preserve information and account for the nonlinearity. We used HydroSHEDS, presently the most highly resolved (3″) global hydrography available, to provide accurate control on global river routing through a computationally efficient algorithm. The high resolution of HydroSHEDS allowed discrimination of river‐channel pixels, and time‐delay distributions were calculated for all such pixels. The distributions were aggregated into network‐response functions (NRFs) for each low‐resolution cell using an algorithm originally developed for the 1‐km‐resolution HYDRO1k hydrography. The large size of HydroSHEDS required a modification in algorithm to maintain computational efficiency. The new algorithm was tested with a high‐quality local and a more uncertain global weather dataset to identify whether improved routing would provide a gain when weather data quality was limiting. The routing was coupled to the WASMOD‐M runoff‐generation model to evaluate discharge from the Dongjiang River and the Willamette River basins. The HydroSHEDS‐based routing, compared with the HYDRO1k‐based routing, provided a small gain in model efficiency, for local and global weather data and for both test basins. The HydroSHEDS‐based routing, contrary to the HYDRO1k‐based routing, provided physically realistic wave velocities. The most stable runoff‐generation parameter values were achieved when HydroSHEDS was used to derive the NRFs. Routing was computed in two steps: first, a preparatory calculation which was a one‐time effort and second, the routing during each simulation. The computational efficiency was four to five orders of magnitude better for the simulation step than that for the preparatory step. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Wastewater dilution index partially explains observed polybrominated diphenyl ether flame retardant concentrations in osprey eggs from Columbia River Basin, 2008–2009

Several polybrominated biphenyl ether (PBDE) congeners were found in all 175 osprey (Pandion haliaetus) eggs collected from the Columbia River Basin between 2002 and 2009. ΣPBDE concentrations in 2008-2009 were highest in osprey eggs from the two lowest flow rivers studied; however, each river flowed through relatively large and populous metropolitan areas (Boise, Idaho and Spokane, Washington). We used the volume of Wastewater Treatment Plant (WWTP) discharge, a known source of PBDEs, as a measure of human activity at a location, and combined with river flow (both converted to millions of gallons/day) created a novel approach (an approximate Dilution Index) to relate waterborne contaminants to levels of these contaminants that reach avian eggs. This approach provided a useful understanding of the spatial osprey egg concentration patterns observed. Individual osprey egg concentrations along the Upper Willamette River co-varied with the Dilution Index, while combined egg data (geometric means) from rivers or segments of rivers showed a strong, significant relationship to the Dilution Index with one exception, the Boise River. There, we believe osprey egg concentrations were lower than expected because Boise River ospreys foraged perhaps 50-75% of the time off the river at ponds and lakes stocked with fish that contained relatively low ΣPBDE concentrations. Our limited temporal data at specific localities (2004-2009) suggests that ΣPBDE concentrations in osprey eggs peaked between 2005 and 2007, and then decreased, perhaps in response to penta- and octa-PBDE technical mixtures no longer being used in the USA after 2004. Empirical estimates of biomagnification factors (BMFs) from fish to osprey eggs were 3.76-7.52 on a wet weight (ww) basis or 4.37-11.0 lipid weight. Our earlier osprey study suggested that ΣPBDE egg concentrations >1,000ng/g ww may reduce osprey reproductive success. Only two of the study areas sampled in 2008-2009 contained individual eggs with ΣPBDE concentrations >1,000ng/g, and non-significant (P>0.30) negative relationships were found between ΣPBDEs and reproductive success. Additional monitoring is required to confirm not only the apparent decline in PBDE concentrations in osprey eggs that occurred during this study, but also to better understand the relationship between PBDEs in eggs and reproductive success.

Portland Milwaukie Light Rail bridge: First transit-only cable-stayed bridge offers unique capacity for shared use

Tri-County Minneapolis Transportation District (TriMet) of Oregon is extending transit service from Portland State University to Milwaukie. As part of this extension, TriMet is constructing a cable-stayed bridge across the Willamette River. When completed, the Portland Milwaukie Light Rail (PMLR) Bridge will be the first transit-only cable-stayed bridge built in the United States and will include capacity for light rail, buses, bicycles, pedestrians, and streetcars in the future. The crossing features a 524 m (1,720 ft.) bridge with a 238 m (780 ft.) main span. A unique aspect of the PMLR Bridge is the sharing of the bridge by light rail transit and pedestrians. A rolling stock analysis was performed to ensure pedestrian comfort during dynamic excitation of the bridge from transit vehicles. A synchronized lateral excitation investigation further ensured pedestrian comfort under the condition of full pedestrian access across the entire bridge during special occasions when the bridge will be closed to transit vehicles.

First Documented Spawning of White Sturgeon in the Lower Willamette River, Oregon

White sturgeon (Acipenser transmontanus) in the lower Columbia River system were previously known to spawn in only one area; within the 12 km of mainstem Columbia River downstream of Bonneville Dam. Our work provides the first documentation of white sturgeon spawning in the Willamette River, Oregon, a major tributary of the lower Columbia River. We used artificial substrates to sample for white sturgeon eggs downstream of Willamette Falls from 18 May to 20 May 2009 and collected a total of 22 fertilized eggs. Embryonic developmental stages ranged from pigmentation change (Stage 2) to early epithelial (Stage 8), corresponding to fertilization times of approximately 5–17 hours prior to collection. We estimated that spawning occurred between 2100 hours on 19 May and 0900 hours on 20 May 2009, and that a minimum of three independent spawning events took place during that time. Results suggest that the area immediately downstream of Willamette Falls may be important white sturgeon spawning habitat, and that the lower Willamette River is likely an additional source of production for the white sturgeon population in the lower Columbia River system.

Using Regression Tree Analysis to Improve Predictions of Low-Flow Nitrate and Chloride in Willamette River Basin Watersheds

The use of regression tree analysis is examined as a tool to evaluate hydrologic and land use factors that affect nitrate and chloride stream concentrations during low-flow conditions. Although this data mining technique has been used to assess a range of ecological parameters, it has not previously been used for stream water quality analysis. Regression tree analysis was conducted on nitrate and chloride data from 71 watersheds in the Willamette River Basin to determine whether this method provides a greater predictive ability compared to standard multiple linear regression, and to elucidate the potential roles of controlling mechanisms. Metrics used in the models included a variety of watershed-scale landscape indices and land use classifications. Regression tree analysis significantly enhanced model accuracy over multiple linear regression, increasing nitrate R² values from 0.38 to 0.75 and chloride R² values from 0.64 to 0.85 and as indicated by the ΔAIC value. These improvements are primarily attributed to the ability for regression trees to more effectively handle interactions and manage non-linear functions associated with watershed heterogeneity within the basin. Whereas hydrologic factors governed the conservative chloride tracer in the model, land use dominated control of nitrate concentrations. Watersheds containing higher agricultural activity did not necessarily yield high nitrate concentrations, but agricultural areas combined with either small proportions of forested land or greater urbanization generated nitrate levels far exceeding water quality standards. Although further refinements are recommended, we conclude that regression tree analysis presents water resource managers a promising tool that improves on the predictive ability of standard statistical methods, provides insight into controlling mechanisms, and helps identify catchment characteristics associated with water quality impairment.

The Terrible Meal

And all these things took place in the City of Roses, hard by the Willamette River, in the not-quite-final throes of the Age of Acceleration. Ourtina strove for six days and nights, until the guttural moans of a birth agony issued from hir chamber. And when s/he had accepted the Final Sacrifice, s/he summoned the Cannibals. S/he prostrated before them, saying, my daughters. Ourtina, they answered, making reverence with wrists crossed on breastbones, fingers grazing clavicles. Daughters, I've a riddle. Who among you can guess the answer? So they all clamored, begging to be tested. Ourtina said, the wound I'm thinking of is both throat and blade. Tell me its name. Melissande guessed a supermax prison. Moacir guessed phalloplasty. General Lizz guessed a city. Changing Suffering guessed a cunt. But Nonnieboy guessed correctly, saying, the world. Then all began to mourn and to beseech, crying, Mother, Mother. Tears drenched their cheeks and dampened their clothing. Only General Lizz stood silent, desert-eyed.

Assessment of future runoff trends under multiple climate change scenarios in the Willamette River Basin, Oregon, USA

AbstractWe investigated trends in future seasonal runoff components in the Willamette River Basin (WRB) of Oregon for the twenty‐first century. Statistically downscaled climate projections by Climate Impacts Group (CIG), eight different global climate model (GCM) simulations with two different greenhouse gas (GHG) emission scenarios, (A1B and B1), were used as inputs for the US Geological Survey's Precipitation Runoff Modelling System. Ensemble mean results show negative trends in spring (March, April and May) and summer (June, July and August) runoff and positive trends in fall (September, October and November) and winter (December, January and February) runoff for 2000–2099. This is a result of temperature controls on the snowpack and declining summer and increasing winter precipitation. With temperature increases throughout the basin, snow water equivalent (SWE) is projected to decline consistently for all seasons. The decreases in the centre of timing and 7‐day low flows and increases in the top 5% flow are caused by the earlier snowmelt in spring, decreases in summer runoff and increases in fall and winter runoff, respectively. Winter runoff changes are more pronounced in higher elevations than in low elevations in winter. Seasonal runoff trends are associated with the complex interactions of climatic and topographic variables. While SWE is the most important explanatory variable for spring and winter runoff trends, precipitation has the strongest influence on fall runoff. Spatial error regression models that incorporate spatial dependence better explain the variations of runoff trends than ordinary least‐squares (OLS) multiple regression models. Our results show that long‐term trends of water balance components in the WRB could be highly affected by anthropogenic climate change, but the direction and magnitude of such changes are highly dependent on the interactions between climate change and land surface hydrology. This suggests a need for spatially explicit adaptive water resource management within the WRB under climate change. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Prespawn mortality in adult spring Chinook salmon outplanted above barrier dams

Keefer ML, Taylor GA, Garletts DF, Gauthier GA, Pierce TM, Caudill CC. Prespawn mortality in adult spring Chinook salmon outplanted above barrier dams. Ecology of Freshwater Fish 2010: 19: 361–372. © 2010 John Wiley &amp; Sons A/SAbstract – Dams without fish passage facilities block access to much of the historic spawning habitat of spring Chinook salmon (Oncorhynchus tshawytscha) in Oregon’s Willamette River basin. Adult salmon are routinely outplanted above the dams to supplement natural production, but many die before spawning despite extensive suitable habitat. In 2004–2007, we examined prespawn mortality patterns using live detection and carcass recovery data for 242 radio‐tagged outplants. Total prespawn mortality was 48%, but variability was high, ranging from 0% to 93% for individual release groups. Prespawn mortality was strongly condition dependent, consistently higher for females than males and higher for early release groups. Across years, warm water temperature in the migration corridor and at the collection site was associated with sharply higher mortality. Results highlight a need for better evaluations of the effects of adult mortality on population reintroduction and recovery and relationships among prespawn mortality, dam‐related temperature change and salmon life history and behaviour.

Passage and Behavior of Radio-Tagged Adult Pacific Lampreys (Entosphenus tridentatus) at the Willamette Falls Project, Oregon

Abstract Populations of Pacific lamprey (Entosphenus tridentatus) in the Columbia River basin have declined and passage problems at dams are a contributing factor. We used radio telemetry to monitor the passage of adult Pacific lampreys at the Willamette Falls Project (a hydroelectric dam integrated into a natural falls) on the Willamette River near Portland, Oregon. In 2005 and 2006, fish were captured at the Project, implanted with a radio tag, and released downstream. We tagged 136 lampreys in 2005 and 107 in 2006. Over 90% of the fish returned to the Project in 7 – 9 h and most were detected from 2000 – 2300 h. In 2005, 43 fish (34%) passed the dam via the fishway, with peak passage in August. No fish passed over the falls, but 13% ascended at least partway up the falls. In 2006, 24 fish (23%) passed the Project using the fishway, with most prior to 9 June when the powerhouse was off. Although 19 lampreys ascended the falls, only two passed via this route. The time for fish to pass through the fishway...

Spatial and temporal changes in runoff caused by climate change in a complex large river basin in Oregon

Summary We estimated potential changes in annual, seasonal, and high and low runoff and associated uncertainty in the 218 sub-basins of the Willamette River basin of Oregon for the 2040s and the 2080s. The US Geological Survey’s Precipitation–Runoff Modeling System (PRMS) was calibrated and validated for representative river basins between 1973 and 2006. A regionalization method and GIS analysis determined the PRMS model parameters for ungauged basins. We used a combination of eight general circulation models (GCMs) and two emission scenarios downscaled to 1/16° resolution to estimate spatial and temporal changes in future runoff at a sub-basin scale. The seasonal variability of runoff is projected to increase consistently with increases in winter flow and decreases in summer flow. These trends are amplified under the A1B emission scenario by the end of the 21st century with increases in top 5% flow and decreases in 7-day low flow. The ratio of snow water equivalent to precipitation declined consistently throughout the basins extending into the Cascade Range. The center timing of runoff, the day when half of the water-year flow has passed, is projected to occur earlier in the water year. Snowmelt-dominated basins exhibit large reductions in summer flow in response to increased temperature, while rainfall-dominated basins show large increases in winter flow in response to precipitation change. The spatial and temporal variability of runoff may increase in the future, but the direction and magnitude of these changes depend on sub-basin characteristics such as elevation and geology. Streams flowing from High Cascade basins that contain a large component of groundwater are projected to sustain summer flows, although the uncertainty associated with future projections is high. The main source of uncertainty stems from GCM structure rather than emission scenarios or hydrologic model parameters, but the hydrologic model parameter uncertainty for projecting summer runoff and 7-day low flow is relatively high for Western Cascade basins.

Welcome to Portland--Sitting on the Big One

Welcome Seismological Society of America meeting attendees to Portland, Oregon, my hometown! Home of clear blue skies (when it's not raining), the beautiful Willamette (Wil-LAM-ette) and Columbia rivers, creeks and lakes galore, majestic volcanic peaks (look to the north and east if it's a clear day), green trees, trees, and more trees, delicious pinot noirs, and of course, gigantic earthquakes. Not just big earthquakes but gigantic earthquakes, like magnitude ( M ) 9! Trouble is, hardly anyone knows about it. Well, that's not exactly true. A good number of Portlanders, Oregonians, and Pacific Northwesterners know that earthquakes can occur in this corner of the country, but unfortunately the majority of people rarely think about these lurking hazards and certainly have not prepared for them. The biggest and baddest earthquake sits on the doorstep of the Pacific Northwest, or more specifically beneath our beautiful coastline along the Cascadia subduction zone megathrust between the overlying North America plate and the down-going Juan de Fuca plate. The biggest and baddest earthquake sits on the doorstep of the Pacific Northwest, or more specifically beneath our beautiful coastline along the Cascadia subduction zone megathrust between the overlying North America plate and the down-going Juan de Fuca plate. Yet thousands of high-risk buildings such as unreinforced masonry (URM), tilt-up, preseismic code steel-frame, and vulnerable transportation structures still stand, ready to be damaged or to collapse when the next giant megathrust earthquake strikes. It's been more than three centuries since the last M 9 shook the Pacific Northwest in 1700. The event generated a tsunami that swept over the beaches of northern California, Oregon, Washington, southern British Colombia, and even Japan. A repeat of such an event could result in thousands of deaths, particularly along the coastline, with significant damage to infrastructure as far inland as the Willamette Valley …