Geology topics

Scott J. Brewer

Publications and source records attributed to Scott J. Brewer.

5 recordsLinked to original sources

USGS2013

The Regional Salmon Outmigration Study--survival and migration routing of juvenile Chinook salmon in the Sacramento-San Joaquin River Delta during the winter of 2008-09

Juvenile Chinook salmon (Oncorhynchus tshawytscha) emigrating from natal tributaries of the Sacramento River may use a number of migration routes to navigate the Sacramento-San Joaquin River Delta (hereafter called “the Delta”), each of which may influence their probability of surviving. We applied a mark-recapture model to data from acoustically tagged juvenile late fall-run Chinook salmon that migrated through the Delta during the winter of 2008–09 to estimate route entrainment, survival, and migration times through the Delta. A tag-life study was conducted to determine the potential for premature tag failure. Tag failure began after 12 days and continued until the 45th day. Travel times of tagged fish exceeded minimum tag-failure times, indicating that survival estimates obtained from this study were negatively biased due to tag failure prior to fish exiting the Delta. Survival estimates were not adjusted and represent the joint probability of tag survival and fish survival. However, relative comparisons of survival among Chinook salmon choosing different routes appeared to be robust to tag failure, and migration-routing parameters were unaffected by tag failure. Migration-routing patterns were consistent among release groups. The Sacramento River was the primary migration route for all release groups except one. The percentage of fish entering the Sacramento River ranged from 33 to 55 percent. Sutter and Steamboat Sloughs were the secondary migration route for 9 of the 10 releases. The percentage of fish migrating through this route ranged from 10 to 35 percent. Entrainment into the interior Delta ranged from 15 to 33 percent. The Delta Cross Channel gates were open for 7 of the 10 releases. Entrainment into the interior Delta through the cross channel ranged from 1 to 27 percent. We estimated route-specific survival for 10 release groups that were released between November 14, 2008, and January 19, 2009. Population-level survival through the Delta (S Delta ) ranged from 0.019 (standard error of 0.012) to 0.277 (standard error of 0.041) among releases, which represent the probability of a fish surviving from Sacramento to Chipps Island with an operational transmitter. Sacramento River flows throughout the study period were approximately 8,000–15,000 cubic feet per second at Freeport, suggesting that variability in flow contributed little to differences in survival between releases. Fish migrating through the Sacramento River had the highest survival for most releases. Survival in Sutter and Steamboat Sloughs was slightly lower than survival in the Sacramento River for 7 of the 10 releases, but higher than survival in the Sacramento River for 3 releases. Survival in the interior Delta was lowest for all release groups except for one release in November. With the exception of this November release, survival patterns across release groups were similar to those of previous studies.

California↗

USGS2012

Simulated effects of dam removal on water temperatures along the Klamath River, Oregon and California, using 2010 Biological Opinion flow requirements

Computer model simulations were run to determine the effects of dam removal on water temperatures along the Klamath River, located in south-central Oregon and northern California, using flow requirements defined in the 2010 Biological Opinion of the National Marine Fisheries Service. A one-dimensional, daily averaged water temperature model (River Basin Model-10) developed by the U.S. Environmental Protection Agency Region 10, Seattle, Washington, was used in the analysis. This model had earlier been configured and calibrated for the Klamath River by the U.S. Geological Survey for the U.S. Department of the Interior, Klamath Secretarial Determination to simulate the effects of dam removal on water temperatures for current (2011) and future climate change scenarios. The analysis for this report was performed outside of the scope of the Klamath Secretarial Determination process at the request of the Bureau of Reclamation Technical Services Office, Denver, Colorado.  For this analysis, two dam scenarios were simulated: “dams in” and “dams out.” In the “dams in” scenario, existing dams in the Klamath River were kept in place. In the “dams out” scenario, the river was modeled as a natural stream, without the J.C. Boyle, Copco1, Copco2, and Iron Gate Dams, for the entire simulation period. Output from the two dam scenario simulations included daily water temperatures simulated at 29 locations for a 50-year period along the Klamath River between river mile 253 (downstream of Link River Dam) and the Pacific Ocean. Both simulations used identical flow requirements, formulated in the 2010 Biological Opinion, and identical climate conditions based on the period 1961–2009.  Simulated water temperatures from January through June at almost all locations between J.C. Boyle Reservoir and the Pacific Ocean were higher for the “dams out” scenario than for the “dams in” scenario. The simulated mean monthly water temperature increase was highest [1.7–2.2 degrees Celsius (°C)] in May downstream of Iron Gate Dam. However, from August to December, dam removal generally cooled water temperatures. During these months, water temperatures decreased 1°C or more between Copco Lake and locations 50 miles or more downstream. The greatest mean monthly temperature decrease was 4°C in October just downstream of Iron Gate Dam. Near the ocean, the effects of dam removal were small (less than 0.2°C) for most months. However, the mean November temperature near the ocean was almost 0.5°C cooler with dam removal.

Open-File Report↗

USGS2012

Survival and migration route probabilities of juvenile Chinook salmon in the Sacramento-San Joaquin River Delta during the winter of 2009-10

Juvenile Chinook salmon ( Oncorhynchus tshawytscha ) emigrating from natal tributaries of the Sacramento River may use a number of migration routes to negotiate the Sacramento-San Joaquin River Delta (hereafter, "the Delta"), each of which may influence their probability of surviving. We applied a mark-recapture model to data from acoustically tagged juvenile late-fall Chinook salmon that migrated through the Delta during the winter of 2009-10 (hereafter, 2010). This report presents findings from our fourth year of research. We estimated route-specific survival for four release groups: two release groups that migrated through the Delta in December 2009 and January 2010, and two release groups that migrated during February 2010. Population-level survival through the Delta ( S Delta ) ranged from 0.374 (SE = 0.040) to 0.524 (SE = 0.034) among releases. Although river flows for the February release groups were substantially higher (20,000-40,000 ft 3 /s at Freeport) than for the December release groups (about 10,000 ft 3 /s), S Delta did not differ considerably between release groups. Among migration routes, fish migrating through the Sacramento River exhibited the highest survival, and fish entering the interior Delta exhibited the lowest survival. Fish entering Sutter and Steamboat Sloughs had lower survival than fish entering the Sacramento River during December, but similar survival during February. These patterns were consistent among release groups, and strikingly similar to patterns observed in previous years. Migration routing varied among release groups partly because of differences in river discharge between releases. For the two December release groups, 26.5 and 28.9 percent of fish entered the interior Delta; for the two February release groups, 10.4 and 17.9 percent of fish entered the interior Delta. Differences in routing probabilities between December and February are partly related to the inverse relationship between flow and the fraction of discharge entering the interior Delta. The proportion of fish diverted into the interior Delta also can be affected by the status of the Delta Cross Channel's gates. The fraction of fish entering Sutter and Steamboat Sloughs also varied considerably among release groups from 22.1 to 44.7 percent, and did not appear correlated to river discharge. For example, the lowest and highest proportion of fish entering Sutter and Steamboat Sloughs occurred during February. Because fish entering Sutter and Steamboat Sloughs bypass the entrance to the interior Delta, a high proportion of fish migrating into this route reduces the proportion of fish entering the interior Delta.

California↗

USGS2011

Simulating daily water temperatures of the Klamath River under dam removal and climate change scenarios

A one-dimensional daily averaged water temperature model was used to simulate Klamath River temperatures for two management alternatives under historical climate conditions and six future climate scenarios. The analysis was conducted for the Secretarial Determination on removal of four hydroelectric dams on the Klamath River. In 2012, the Secretary of the Interior will determine if dam removal and implementation of the Klamath Basin Restoration Agreement (KBRA) (Klamath Basin Restoration Agreement, 2010) will advance restoration of salmonid fisheries and is in the public interest. If the Secretary decides dam removal is appropriate, then the four dams are scheduled for removal in 2020. Water temperature simulations were conducted to compare the effect of two management alternatives: the no-action alternative where dams remain in place, and the action alternative where dam removal occurs in 2020 along with habitat restoration. Each management alternative was simulated under historical climate conditions (1961-2010) and six 50-year (2012-2061) climate scenarios. The model selected for the study, River Basin Model-10 (RBM10), was used to simulate water temperatures over a 253-mile reach of the Klamath River located in south-central Oregon and northern California. RBM10 uses a simple equilibrium flow model, assuming discharge in each river segment on each day is transmitted downstream instantaneously. The model uses a heat budget formulation to quantify heat flux at the air-water interface. Inputs for the heat budget were calculated from daily-mean meteorological data, including net shortwave solar radiation, net longwave atmospheric radiation, air temperature, wind speed, vapor pressure, and a psychrometric constant needed to calculate the Bowen ratio. The modeling domain was divided into nine reaches ranging in length from 10.8 to 42.4 miles, which were calibrated and validated separately with measured water temperature data collected irregularly from 1961 to 2010. Calibration root mean square errors of observed versus simulated water temperatures for the nine reaches ranged from 0.8 to 1.5 degrees C. Mean absolute errors ranged from 0.6 to 1.2 degrees C. For model validation, a k-fold cross-validation technique was used. Validation root mean square error and mean absolute error for the nine reaches ranged from 0.8 to 1.4 degrees C and 0.8 to 1.2 degrees C, respectively. Input data for the six future climate scenarios (2012-2061) were derived from historical hydrological and meteorological data and simulated meteorological output from five Global Circulation Models. Total Maximum Daily Loads or other regulatory processes that might reduce future water temperatures were not included in the simulations. Under the current climate conditions scenario, impacts of dam removal on water temperatures were greatest near Iron Gate Dam (near Yreka, California) and were attenuated in the lower reaches of the Klamath River. May and October simulated mean water temperatures increased and decreased by approximately 1-2 degrees C and 2-4 degrees C, respectively, downstream of Iron Gate Dam after dam removal. Dam removal also resulted in an earlier annual temperature cycle shift of 18 days, 5 days, and 2 days, near Iron Gate Dam, Scott River, and Trinity River, respectively. Although the magnitude of precipitation and air temperature change predicted by the five Global Circulation Models varied, all five models resulted in progressive incremental increases in water temperatures with each decade from 2012 to 2061. However, dam removal under KBRA appeared to delay the effects of climate change to some extent near Iron Gate Dam. With dam removal under KBRA, annual-mean water temperatures exceeded the 49-year historical mean temperature beginning in 2045; whereas with dams, annual-mean temperatures exceeded the historical mean beginning in 2025. Potential changes in seasonal water temperatures resulting from dam removal, with or without future climat

Open-File Report↗

USGS2010

Assessing survival of Mid-Columbia River released juvenile salmonids at McNary Dam, Washington, 2008-09

Few studies have evaluated survival of juvenile salmon over long river reaches in the Columbia River and information regarding the survival of sockeye salmon at lower Columbia River dams is lacking. To address these information gaps, the U.S. Geological Survey was contracted by the U.S. Army Corps of Engineers to evaluate the possibility of using tagged fish released in the Mid-Columbia River to assess passage and survival at and downstream of McNary Dam. Using the acoustic telemetry systems already in place for a passage and survival study at McNary Dam, fish released from the tailraces of Wells, Rocky Reach, Rock Island, Wanapum, and Priest Rapids Dams were detected at McNary Dam and at the subsequent downstream arrays. These data were used to generate route-specific survival probabilities using single-release models from fish released in the Mid-Columbia River. We document trends in passage and survival probabilities at McNary Dam for yearling Chinook and sockeye salmon and juvenile steelhead released during studies in the Mid-Columbia River. Trends in the survival and passage of these juvenile salmonid species are presented and discussed. However, comparisons made across years and between study groups are not possible because of differences in the source of the test fish, the type of acoustic tags used, the absence of the use of passive integrated transponder tags in some of the release groups, differences in tagging and release protocols, annual differences in dam operations and configurations, differences in how the survival models were constructed (that is, number of routes that could be estimated given the number of fish detected), and the number and length of reaches included in the analysis (downstream reach length and arrays). Despite these differences, the data we present offer a unique opportunity to examine the migration behavior and survival of a group of fish that otherwise would not be studied. This is particularly true for sockeye salmon because little information is available about their survival as they pass hydroelectric dams in the lower Columbia River. Collecting information on fish released in the Mid-Columbia River, as well as on fish released 8 kilometers upstream of McNary Dam, allowed us to evaluate similarities and differences in passage and survival probabilities. In general, juvenile salmonids released in the Mid-Columbia River and detected at and downstream of McNary Dam showed trends in passage and survival probabilities that were similar to fish released 8 kilometers upstream of McNary Dam. This suggests that increased migration time or length of migration had little effect on behavior and survival of Mid-Columbia River released juvenile salmonids detected at McNary Dam.

Open-File Report↗