Water Resources of Oregon

USGS Oregon WSC Highlights

Environmental Flow Monitoring on the Middle Fork Willamette and McKenzie Rivers of Western Oregon

The USGS Oregon Water Science Center has been conducting an ongoing environmental flow monitoring study in cooperation with The Nature Conservancy (TNC) and U.S. Army Corps of Engineers (USACE) in support of the Sustainable Rivers Project (SRP) of TNC and USACE. The goal of this study is to evaluate and characterize relations between streamflow, geomorphic processes, and black cottonwood (Populus trichocarpa) recruitment on the Middle Fork Willamette and McKenzie Rivers, western Oregon, that were hypothesized in earlier investigations. The SRP can use this information to plan future monitoring and scientific investigations, and to help mitigate the effects of dam operations on streamflow regimes, geomorphic processes, and biological communities, such as black cottonwood forests, in consultation with regional experts. Read about the results of the study here.

Modeling Streamflow and Temperature in the Middle Fork Willamette River Under Various Dam Operational Scenarios

Streamflow and water temperature in the Middle Fork Willamette River, western Oregon, have been regulated and altered since the construction of Lookout Point, Dexter, and Hills Creek Dams in 1954 and 1961, respectively. Each year, summer releases from the dams typically are cooler than pre-dam conditions, with the reverse (warmer than pre-dam conditions) occurring in autumn. This pattern has been detrimental to habitat of endangered Upper Willamette River Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River winter steelhead (O. mykiss) throughout multiple life stages. In this study, scenarios testing different dam-operation strategies and hypothetical dam-outlet structures were simulated using CE-QUAL-W2 hydrodynamic/temperature models of the Middle Fork Willamette River system from Hills Creek Lake to Lookout Point and Dexter Lakes to explore and understand the efficacy of potential flow and temperature mitigation options.

Model scenarios were run in constructed wet, normal, and dry hydrologic calendar years, and designed to minimize the effects of Hills Creek and Lookout Point Dams on river temperature by prioritizing warmer lake surface releases in May–August and cooler, deep releases in September–December. Operational scenarios consisted of a range of modified release rate rules, relaxation of power-generation constraints, variations in the timing of refill and drawdown, and maintenance of different summer maximum lake levels at Hills Creek Lake and Lookout Point Lake. Structural scenarios included various combinations of hypothetical floating outlets near the lake surface and hypothetical new outlets at depth. Scenario results were compared to scenarios using existing operational rules that give temperature management some priority, scenarios using pre-2012 operational rules that prioritized power generation over temperature management, and estimated temperatures from a without-dams condition. Results of the modeling can be viewed here.

Stormwater Runoff of Urban-Use Pesticides to Streams Likely Impairs Invertebrate Assemblages

Insecticide use in urban areas results in the detection of these compounds in streams following stormwater runoff at concentrations likely to cause toxicity for stream invertebrates such as aquatic insects. In a 2013 study, stormwater runoff and streambed sediments were analyzed for 91 pesticides dissolved in water and 118 pesticides on sediment. Detections included 33 pesticides, including insecticides, fungicides, herbicides, degradates, and a synergist. Patterns in pesticide occurrence reveal transport of dissolved and sediment-bound pesticides, including pyrethroids, from upland areas through stormwater outfalls to receiving streams. Nearly all streams contained at least one insecticide at levels exceeding an aquatic-life benchmark, most often for bifenthrin and (or) fipronil. Multiple U.S. EPA benchmark or criterion exceedances occurred in 40% of urban streams sampled. Bed sediment concentrations of bifenthrin were highly correlated (p<0.001) with benthic invertebrate assemblages. Non-insects and tolerant invertebrates such as amphipods, flatworms, nematodes, and oligochaetes dominated streams with relatively high concentrations of bifenthrin in bed sediments, whereas insects, sensitive invertebrates, and mayflies were much more abundant at sites with no or low bifenthrin concentrations. The abundance of sensitive invertebrates was strongly negatively correlated with organic-carbon normalized bifenthrin concentrations in streambed sediments. These findings, from western Clackamas County, Oregon, expand upon previous research demonstrating the transport of pesticides from urban landscapes and linking impaired benthic invertebrate assemblages in urban streams with exposure to pyrethroid insecticides. Read the journal article.

A Warming Climate Could Alter the Ecology of Crater Lake

Warming air temperature is predicted to change water temperature and water column mixing in Oregon’s Crater Lake over the next several decades, potentially impacting the clarity and health of the iconic lake, according to a U.S. Geological Survey study. Researchers from the USGS, University of Trento in Italy, and Crater Lake National Park analyzed how climate conditions currently affect the fundamental temperature characteristics and water-column mixing processes in Crater Lake, the deepest lake in the U.S. and one of the clearest in the world.

USGS modeling showed that warming of the atmosphere caused by climate change could disrupt the deep mixing process in Crater Lake. As the atmosphere warms, deep mixing events will likely become less frequent. Under the least severe warming scenario, deep mixing will occur on average once every three years by 2100. Under the most severe scenario, deep mixing could stop completely, halting the movement of dissolved oxygen to organisms in the deep lake. Predicting the effect these changes will have on the ecology of Crater Lake and its famous water clarity will require models that combine the deep-mixing model results with factors that affect algal growth and oxygen use by deep-lake organisms. Read more about the study.

Analyzing the Dynamics of Blue-Green Algae Blooms in an Oregon Reservoir

The occurrence of harmful algal blooms in Oregon and other western states has increased sharply over the past few decades. Blue-green algae blooms in lakes, reservoirs, and rivers have resulted in dog deaths, recreational closures, and concerns about possible algal toxins in water supplies. Health advisories triggered by these blooms have been issued by the Oregon Health Authority on nearly 50 water-bodies in Oregon, from coastal lakes, to rivers, to reservoirs, including the 125 acre Willow Creek Reservoir near Heppner, in eastern Oregon.

The U.S. Geological Survey and U.S. Army Corps of Engineers are cooperating to understand the spatial dynamics and timing of blue-green algae blooms in Willow Creek Reservoir. The study uses a combination of visual, instrument, and satellite monitoring to assess the ability of these methods to detect the onset of the summer bloom. A monitoring camera will be placed on the dam in the northwest corner of the reservoir, where blooms tend to accumulate owing to prevailing summer winds. The camera will capture images of the reservoir surface every 15 minutes during daylight hours. The reservoir images will be available in near realtime to alert the Corps of when to sample for algal toxins, allowing the Oregon Health Authority to issue timely advisories.

In addition to camera monitoring, the USGS will conduct water sampling in the reservoir during blooms when the camera detects algal accumulation near the dam. Using data from each sampling trip, researchers will produce maps of water temperature, pH, specific conductance, dissolved oxygen, turbidity, and algal-bloom density. LandSat images will augment the water sampling. These maps will help provide the Corps with knowledge of when and where to expect harmful algal blooms in the reservoir.

Blue-Green Algae from Agricultural Drainage Affects Water Quality of the Tualatin River

In early July 2008, a large blue-green algae bloom was discovered in the lower Tualatin River, which is a tributary to the Willamette River in northwestern Oregon (fig. 1). Although floating algal mats had occurred approximately 30 years prior, this bloom was the worst in memory for many water-quality scientists and managers familiar with the Tualatin River. This slow-moving, warm, and nutrient-enriched section of river has a long history of water-quality problems related to summer algal blooms through the 1980s. Upgrades in wastewater treatment in the early 1990s greatly diminished the severity of the blooms by capping nutrient levels, and flow augmentation from upstream reservoirs has added dilution and increased water velocity that reduces the time available for blooms to develop. The 2008 bloom, though, was different in many ways.

The USGS, in cooperation with Clean Water Services, traced the source of the bloom to Wapato Lake, an agricultural drain that discharges to the Tualatin River in summer. The bloom provided useful information and lessons for agencies managing public health, wetlands, agricultural activities, and water quality in the Tualatin River basin and similar river basins elsewhere. Results and insights derived from this study can be used to enhance future monitoring and data collection strategies designed to improve water quality and plankton models and better predict dissolved-oxygen concentrations in the lower Tualatin River.

USGS Data Helps Light Up the New Tilikum Crossing Bridge in Portland

On September 10, 2015, the Portland waterfront added a stunning new feature to the city’s nighttime skyline. The Tillikum Crossing bridge showcases a wonderfully artistic amalgamation of art and science every night. Using U.S. Geological Survey water-quality and streamflow data collected from the Willamette River at the Morrison Street Bridge, Portland's TriMet transit service is illuminating the bridge using dynamic lighting based on river velocity, water height, and water temperature. River conditions are translated by specialized software and displayed along the cables and pillars of the new bridge using LED lights. The lights’ base color changes with the river’s temperature. The speed of the colored lights moving across the bridge represents the velocity of the water in the river. Vertical lighting elements up and down the pillars and cables correspond to the height of the water in the river.

USGS Study Explores Geothermal and Groundwater Resources in Parts of Oregon, Idaho, Nevada, and California

A joint study between the USGS Water and Energy Mission Areas has the main goals of quantifying groundwater resources and geothermal energy potential in much of eastern Oregon, northeastern California, southwestern Idaho, and northernmost Nevada. This study area lies within a broadly-defined Northwest Volcanic Province (NVP) that has been dominated by volcanic eruptions that have shaped the landscape over the past approximately 17 million years. Although the sparsely populated study area has been the subject of relatively little systematic hydrogeologic study, previous geothermal research has identified high geothermal heat flow that may be used to generate large amounts of electricity. In this area, groundwater is the major source of year-round dependable water supply, and water is a necessary component of geothermal energy development. Further, because flowing groundwater moves heat beneath the earth’s surface, interpretation of geothermal heat flow patterns are greatly improved when groundwater flow patterns are taken into account. Read more about the study.

The USGS is working with the U.S. Army Corps of Engineers to Ensure the Survival of Threatened and Endangered Salmonids

The North Santiam River drains a large area of the western slope of the Cascade Range in northwestern Oregon and is one of several major tributaries to the Willamette River. Detroit Dam was constructed on the North Santiam River in 1953 by the U.S. Army Corps of Engineers and resulted in the formation of Detroit Lake. Detroit Dam is the tallest dam (463 ft) in the Willamette River Basin and impounds 455,100 acre-ft of water at full pool, making it one of the largest reservoirs in the basin. Detroit Lake is one of the most important hydroelectric and recreational resources among the 13 reservoirs managed by the Corps in the Willamette Valley.

The North Santiam River and its tributaries provide habitat for endangered Upper Willamette River Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River winter steelhead (Oncorhynchus mykiss). These species and other salmonids require specific flow and temperature regimes to thrive. To protect and enhance their habitats, the National Marine Fisheries Service wrote a 2008 Willamette Basin Biological Opinion (BiOp) that urges the Corps to assess the feasibility of developing project-specific alternatives for achieving long-term temperature control at the Big Cliff–Detroit Dam complex. The Corps is in the process of evaluating alternatives for both current and long-term downstream temperature management and fish passage at many of the dams in the Willamette Project.

The USGS Oregon Water Science Center is cooperating with the Corps of Engineers to improve downstream temperature conditions for fish in the North Santiam River by using models to determine how operational and structural modifications can affect the temperature regime in the river. Read about the results to date of this study in a recently released report and one released in 2012.

USGS Scientists Are Studying the Causes of Amphibian Declines

With global biodiversity decreasing, it has become important for scientists to find new and innovative tools to quickly assess how environmental hazards affect wildlife, especially threatened or endangered species. This information aids researchers and resource managers alike by providing early detection of potential problems that may require immediate conservation efforts or further detailed investigation. Of all species, amphibians (frogs, toads, salamanders, and newts) appear especially vulnerable to environmental hazards, with up to 41% considered threatened worldwide.

One potentially lethal threat is the amphibian chytrid fungus, Batrachochytrium dendrobatidis, as well as the newly described salamander chytrid fungus, B. salamandrivorans; both cause the disease chytridiomycosis. B. dendrobatidis is linked to many of the observed amphibian population declines and extinctions globally, and B. salamandrivorans has caused recent declines in European salamanders, although it does not yet appear to have made it to North America. A recent study by the U.S. Geological Survey published in the journal PLoS One highlights the use of promising tools that can be used to assess the risk of disease exposure for amphibians. Among the benefits of these tools, scientists have been able to improve survey protocols, which increases the chances of detecting the B. dendrobatidis in the environment while reducing the risk of a false-negative. More importantly, these tools are not limited to only studying B. dendrobatidis. These same methods can be modified to quickly and affordability to provide early detection for diseases like B. salamandrivorans, and study other aquatic diseases that pose risks to the health of wildlife and humans alike.

Study Assesses Groundwater Resources in the Willamette Basin

Full appropriation of tributary streamflow during summer, a growing population, and agricultural needs are increasing the demand for groundwater in the Willamette Basin. Greater groundwater use could diminish streamflow and create seasonal and long-term declines in groundwater levels. The U.S. Geological Survey and the Oregon Water Resources Department cooperated in a study to develop a conceptual and quantitative understanding of the groundwater-flow system of the Willamette Basin with an emphasis on the Central Willamette subbasin. This final report from the cooperative study describes numerical models of the regional and local groundwater-flow systems and evaluates the effects of pumping on groundwater and surface-water resources. The models described in this report can be used to evaluate the effects of pumping on groundwater, base flow, and stream capture.

The Willamette Basin is a topographic and structural trough that lies between the Coast Range and the Cascade Range in northwestern Oregon. It has five sedimentary subbasins underlain and separated by basalts of the Columbia River Basalt Group (Columbia River basalt) that crop out as local uplands. The regional model covers about 6,700 square miles of the 12,000-square-mile Willamette and adjacent Sandy River drainage basins.

Read more about this study.

Are Contaminants in the Columbia River System a Cause of Lamprey Declines?

Lampreys are members of an ancient order of jawless, cartilagenous fishes that have existed for as long as 400 million years. Pacific lampreys (Entosphenus tridentatus), one of 38 modern lamprey species, have inhabited Pacific Northwest river basins for possibly millions of years. Pacific lamprey are parasitic on ocean-going fishes, such as salmon. They are integral to the ecology of these river basins, and are culturally significant to several Northwest Tribes. Lamprey populations in the Pacific Northwest and other parts of the world have declined dramatically in recent decades, probably owing to multiple causes. The role of habitat contamination in the declines has rarely been studied and is the main objective of a joint study by the USGS and the Columbia River Intertribal Fish Commission.

The goal of the study is to provide information about the bioaccumulation of several classes of contaminants of concern in larval and adult Pacific lampreys and habitat in key areas of the Columbia River Basin. The study will assess organism health during sensitive life stages before their transformation to adults, compare concentrations in larval tissues to levels in adult lampreys, and consider lamprey and human health implications. Phase 1 of the study, already completed, provided reconnaissance-based information on exposure and bioaccumulation of organic contaminants in larval, filter-feeding lampreys. Phase 2 will concentrate on adult lamprey.

Read more about Phase 1 and Phase 2 of this study.