Geology topics

Norman L. Buccola

Publications and source records attributed to Norman L. Buccola.

15 recordsLinked to original sources

USGS2023

Updates to CE-QUAL-W2 models for select U.S. Army Corps of Engineers reservoirs in the Willamette Valley Project and an inter-reservoir reach of the Middle Fork Willamette River, northwestern Oregon

Mechanistic models capable of simulating hydrodynamics and water temperature in rivers and reservoirs are valuable tools for investigating thermal conditions and their relation to dam operations and streamflow in river basins where upstream water storage and management decisions have an important influence on river reaches with threatened fish populations. In particular, models allow managers to investigate how new, untried operations or hypothetical structures might influence streamflow and temperature conditions downstream. CE-QUAL-W2 is a two-dimensional (laterally averaged) hydrodynamic water-quality model that has previously been used to investigate the downstream effects of dam operations and other anthropogenic influences on stream temperature in the Willamette River Basin in northwestern Oregon, a region with two populations of fish species designated as threatened under the Endangered Species Act. By linking CE-QUAL-W2 river models to models of upstream, large Willamette Valley Project dams and reservoirs, these models can be used to investigate how dam operations at individual dams can influence streamflow and thermal conditions in downstream river reaches as an integrated system. Integrated model simulations that include the large dams and reservoirs linked to downstream river reaches can help managers develop a better understanding of tradeoffs associated with potential retrofits or operational changes across the multipurpose dams in the Willamette Valley Project, the effect of dam management on downstream tributaries and the Willamette River, and the resulting potential effect on threatened fish populations and habitat conditions. River models capable of simulating river corridors downstream from U.S. Army Corps of Engineers dams were previously updated and integrated to simulate conditions that occurred from March through October of 2011 (a cool and wet year), 2015 (a hot and dry year), and 2016 (a moderately hot and dry year) using CE-QUAL-W2 version 4.2. These river models encompass the following: Coast Fork Willamette and Middle Fork Willamette Rivers, the Row River, and Fall Creek downstream from Cottage Grove, Dexter, Dorena, and Fall Creek Dams, respectively; South Fork McKenzie River downstream from Cougar Dam; McKenzie River downstream from its confluence with the South Fork McKenzie River; South Santiam River downstream from Foster Dam; North Santiam River downstream from Big Cliff Dam; and Willamette River from its start at the confluence of the Middle Fork Willamette and Coast Fork Willamette Rivers to Willamette Falls (river mile 26.0; near West Linn, Oregon). This report documents model modifications, boundary condition data sources or estimation methods, and goodness-of-fit statistics for six CE-QUAL-W2 reservoir models and one river model upstream from the existing river models. These models simulate (1) Hills Creek Lake; (2) Lookout Point Lake and Dexter Reservoir on the Middle Fork Willamette River; (3) the Middle Fork Willamette River reach between Hills Creek Dam upstream and Lookout Point Lake downstream; (4) Cougar Reservoir on the South Fork McKenzie River; (5) Green Peter Lake on the Middle Santiam River and Foster Lake on the South Santiam River; and (6) Detroit Lake and (7) Big Cliff Reservoir on the North Santiam River. These CE-QUAL-W2 models were built by a variety of researchers to simulate a range of conditions in past years; this report documents their upgrade to U.S. Geological Survey (USGS) edition 7 of version 4.2 of CE-QUAL-W2 and updates each model to simulate conditions from January through December of 2011, 2015, and 2016. Also included in this report is an explanation of modifications to the CE-QUAL-W2 source code that constitute USGS edition 7 of CE-QUAL-W2 version 4.2. Each of the models described in this report can be run in isolation or linked to downstream models as a “system model” to simulate conditions in tributaries and (or) in the Willamette Valley Project as a whole. As part of the model updates described in this report, some model parameters were adjusted to improve stability or decrease model error, and boundary conditions including meteorological, hydrologic, and temperature inputs were developed and updated for model years 2011, 2015, and 2016, as necessary. In some cases, the data sources used to drive previous model versions were no longer available, which required the development and checking of new data sources or estimation techniques. Goodness-of-fit statistics for outflow from the dams and in simulated river reaches generally show a good model fit, with the models simulating subdaily water temperatures at most comparable locations with a mean absolute error of generally less than 1 degree Celsius (°C) and a reasonably low bias. Model simulation of the thermal vertical profiles in each reservoir also produced an overall mean absolute error of generally less than 1 °C for all 3 years, with the exception of the Hills Creek Lake Model and the Cougar Reservoir Model in years when the reservoirs did not fill (2015 and 2016). Both of these models have known calibration issues and tend to be sensitive to the choice of certain structural parameters in the model. Overall, the calibration process was focused on obtaining model settings that led to realistic water temperature predictions in all 3 years (2011, 2015, and 2016) without over-calibrating specifically to any single year. A complete investigation of model error for these reservoir submodels was beyond the scope of this investigation but could be undertaken in the future if better model performance for these two reservoirs is desired.

Oregon↗

USGS2022

Updates to models of streamflow and water temperature for 2011, 2015, and 2016 in rivers of the Willamette River Basin, Oregon

Mechanistic river models capable of simulating hydrodynamics and stream temperature are valuable tools for investigating thermal conditions and their relation to streamflow in river basins where upstream water storage and management decisions have an important influence on river reaches with threatened fish populations. In the Willamette River Basin in northwestern Oregon, a two-dimensional, hydrodynamic water-quality model (CE ‑ QUAL ‑ W2) has been used to investigate the downstream effects of dam operations and other anthropogenic influences on stream temperature. By simulating the managed releases of water and various temperatures from the large Willamette Valley Project dams upstream of the modeling domain, these models can be used to investigate riverine temperature conditions and their relation to streamflow to determine where and when conditions are most challenging for threatened fish populations and how dam operations and flow management can affect and optimize thermal conditions in the river. The original models were initially developed to simulate conditions in spring–autumn of 2001 and 2002. This report documents (1) the upgrade of the river models to CE‑QUAL‑W2 version 4.2 and (2) the update of those models to simulate conditions that occurred from March through October of 2011, 2015, and 2016. These years were selected to represent a range of climatic and hydrologic conditions in the Willamette River Basin, including a “cool, wet” year (2011), a “hot, dry” year (2015), and a “normal” year (2016). Six submodels comprise the modeling system updated in this report; each submodel can be run independently or run with the others as a system. These models include the Coast Fork and Middle Fork Willamette River submodel, which includes the Coast Fork and Middle Fork Willamette Rivers, the Row River, and Fall Creek; the McKenzie River submodel, which includes the South Fork McKenzie River downstream of Cougar Dam and the McKenzie River from its confluence with the South Fork McKenzie River to its mouth; the South Santiam River submodel, which comprises the South Santiam River from Foster Dam to the Santiam River; the North Santiam and Santiam River submodel, which includes the Santiam River and the North Santiam River downstream of Big Cliff Dam; the Upper Willamette River submodel, which includes the Willamette River from Eugene to Salem; and the Middle Willamette River submodel, which includes the Willamette River from Salem to Willamette Falls near Oregon City. The models included in this report were originally developed, calibrated, and documented by other researchers. As part of the model updates described here, some model parameters were adjusted to improve stability and decrease runtime. Boundary conditions including meteorological, hydrologic, and thermal parameters were developed and updated for model years 2011, 2015, and 2016. In many cases, the data sources used to drive the 2001 and 2002 models were no longer available, which required the use of new data sources, the determination of a proxy record, or the development of appropriate estimation techniques. Goodness-of-fit statistics for the updated models show a good model fit, with the models simulating subdaily water temperatures at most comparable locations with a mean absolute error of generally less than 1 °C and often nearing 0.5 °C, depending on the individual submodel, and a reasonably low bias. The subdaily mean error for the South Santiam River submodel produced the highest bias of any of the submodels. Goodness-of-fit statistics indicate that the results may be biased cool (ranging from -0.43 °C in 2016 to -0.80 °C in 2011 for subdaily results), but the only water temperature data available for comparison on the South Santiam River is itself estimated, and those estimates are known to be too high in summer. Depending on future modeling needs, that submodel may warrant further refinement, along with additional data collection to properly define and minimize any model bias.

Oregon↗

USGS2022

Estimating stream temperature in the Willamette River Basin, northwestern Oregon—A regression-based approach

The alteration of thermal regimes, including increased temperatures and shifts in seasonality, is a key challenge to the health and survival of federally protected cold-water salmonids in streams of the Willamette River basin in northwestern Oregon. To better support threatened fish species, the U.S. Army Corps of Engineers (USACE) and other water managers seek to improve the thermal regime in the Willamette River and key tributaries downstream of USACE dams by utilizing strategically timed flow releases from USACE dams. To inform flow management decisions, regression relations were developed for 12 Willamette River basin locations below USACE dams relating stream temperature with streamflow and air temperature utilizing publicly available datasets spanning 2000–18. The resulting relations provide simple tools to investigate stream temperature responses to changes in streamflow and climatic conditions in the Willamette River system. Regression relations on the Willamette River and key tributaries show that, at locations sufficiently distant from the direct temperature influence of upstream dam releases, air temperature and streamflow are reasonable proxies to predict the 7-day average of the daily mean (7dADMean) and 7-day average of the daily maximum (7dADMax) water temperature with errors generally ≤1 degrees Celsius (°C). To account for seasonal variations in the relation between air temperature, streamflow, and stream temperature, a transition-smoothed, seasonal regression approach was used. Stream temperature is inversely correlated with streamflow in all seasons except “winter” (January–March), when it is relatively independent. Stream temperature is positively correlated with air temperature in all seasons, but the slope decreases at very low or very high air temperatures. Generally, fit is best for seasonal models “winter” (January–March), “spring” (April–May), “summer” (June–August), and “early autumn” (September–October). Error in “autumn” (November–December) is larger, probably due to variation in the onset timing of winter storms. Simulated results from a climatological analysis of predicted stream temperature suggest that, excluding extremes and accounting for some seasonal variability, the 7dADMean and 7dADMax stream temperature sensitivity to air temperature and streamflow varies by location on the river. To investigate the potential range of stream temperature variability based on historical air temperature and streamflow conditions, stream temperature predictions were calculated using synthetic time series comprised of daily temperature values representing the 0.10, 0.33, 0.50, 0.67, and 0.90 quantile of air temperature and streamflow from 1954 (the year meaningful streamflow augmentation began) to 2018. Results show that from a “very hot” (0.90 quantile) and “very dry” (0.10 quantile) year to a “very cool” (0.10 quantile) and “very wet” (0.90; all quantiles from 1954 to 2018) year, the stream temperature sensitivity to air temperature and streamflow is about 3 °C at Harrisburg (river mile 161.0) and increases to about 5 °C at Keizer (river mile 82.2). While the number of days exceeding regulatory criteria are fewer in cooler, wetter years than in warmer, dryer years, the models suggest that the Willamette River will likely continue to exceed the State of Oregon maximum water-temperature criterion of 18 °C for sustained periods from late spring to early autumn and that the flow management practices evaluated in this study, while effective at influencing stream temperature, likely cannot prevent many or all such exceedances. As modeled for 2018, a representative very hot year with normal to below-normal streamflow, stream temperature sensitivity to changes in streamflow of ±100 to ±1000 cubic feet per second produced mean monthly temperature changes from 0.0 to 1.4 °C at Keizer, Albany, and Harrisburg during summer. For a specified change in flow, temperature sensitivity is greater at upstream locations where streamflow is less than that at downstream locations because the change in streamflow is a greater percentage of total streamflow at upstream locations. Similarly, temperature response to a set change in flow is greater in the summer and early autumn low-flow season than in spring when flows are higher. The regression models developed in this study thus indicate that flow management is likely to have a greater effect on stream temperature at upstream locations (such as Harrisburg or Albany) and during the low-flow season than at downstream locations (such as Keizer) or during periods of higher streamflow.

Oregon↗

USGS2017

Water temperature effects from simulated changes to dam operations and structures in the Middle and South Santiam Rivers, Oregon

Green Peter and Foster Dams on the Middle and South Santiam Rivers, Oregon, have altered the annual downstream water temperature profile (cycle). Operation of the dams has resulted in cooler summer releases and warmer autumn releases relative to pre-dam conditions, and that alteration can hinder recovery of various life stages of threatened spring-run Chinook salmon ( Oncorhyncus tshawytscha ) and winter steelhead ( O. mykiss ). Lake level management and the use of multiple outlets from varying depths at the dams can enable the maintenance of a temperature regime more closely resembling that in which the fish evolved by releasing warm surface water during summer and cooler, deeper water in the autumn. At Green Peter and Foster Dams, the outlet configuration is such that temperature control is often limited by hydropower production at the dams. Previously calibrated CE-QUAL-W2 water temperature models of Green Peter and Foster Lakes were used to simulate the downstream thermal effects from hypothetical structures and modified operations at the dams. Scenarios with no minimum power production requirements allowed some releases through shallower and deeper outlets (summer and autumn) to achieve better temperature control throughout the year and less year-to-year variability in autumn release temperatures. Scenarios including a hypothetical outlet floating 1 meter below the lake surface resulted in greater ability to release warm water during summer compared to existing structures. Later in Autumn (October 15–December 31), a limited amount of temperature control was realized downstream from Foster Dam by scenarios limited to operational changes with existing structures, resulting in 15-day averages within 1.0 degree Celsius of current operations.

Oregon↗

USGS2016

Water temperature effects from simulated dam operations and structures in the Middle Fork Willamette River, western Oregon

Significant Findings Streamflow and water temperature in the Middle Fork Willamette River (MFWR), 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 (UWR) Chinook salmon ( Oncorhynchus tshawytscha ) and UWR 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 MFWR system from Hills Creek Lake (HCR) to Lookout Point (LOP) and Dexter (DEX) 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 HCR and LOP. 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 ( Base ), scenarios using pre-2012 operational rules that prioritized power generation over temperature management ( NoBlend ), and estimated temperatures from a without-dams condition ( WoDams ). Results of the tested model scenarios led to the following conclusions: The existing outlets at Lookout Point Dam, because of the range of depths, allow for greater temperature control than the two existing outlets at Hills Creek Dam that are relatively deep. Temperature control at HCR through operational scenarios generally was minimal near Hills Creek Dam, but improved downstream toward the head of LOP when decreased release rates held HCR at a low lake elevation year-round. Inflows from unregulated streams between HCR and LOP helped to dilute the effects of HCR and achieve more natural stream temperatures before the MFWR entered LOP. The relative benefit of any particular scenario depended on the location in the MFWR system used to assess the potential change, with most scenarios involving changes to Hills Creek Dam being less effective with increasing downstream distance, such as downstream of DEX. To achieve as much temperature control as the most successful structural scenarios, which were able to resemble without-dam conditions for part of the year, most operational scenarios had to be free of any power-generation requirements at Lookout Point Dam. Downstream of DEX, scenarios incorporating a hypothetical floating outlet at either HCR or LOP resulted in similar temperatures, with both scenarios causing a delay in the estimated spring Chinook egg emergence by about 9–10 days compared to base-case temperature-management scenarios.

Oregon↗

USGS2016

Development of a CE-QUAL-W2 temperature model for Crystal Springs Lake, Portland, Oregon

During summer 2014, lake level, streamflow, and water temperature in and around Crystal Springs Lake in Portland, Oregon, were measured by the U.S. Geological Survey and the City of Portland Bureau of Environmental Services to better understand the effect of the lake on Crystal Springs Creek and Johnson Creek downstream. Johnson Creek is listed as an impaired water body for temperature by the Oregon Department of Environmental Quality (ODEQ), as required by section 303(d) of the Clean Water Act. A temperature total maximum daily load applies to all streams in the Johnson Creek watershed, including Crystal Springs Creek. Summer water temperatures downstream of Crystal Springs Lake and the Golf Pond regularly exceed the ODEQ numeric criterion of 64.4 °F (18.0 °C) for salmonid rearing and migration. To better understand temperature contributions of this system, the U.S. Geological Survey developed two-dimensional hydrodynamic water temperature models of Crystal Springs Lake and the Golf Pond. Model grids were developed to closely resemble the bathymetry of the lake and pond using data from a 2014 survey. The calibrated models simulated surface water elevations to within 0.06 foot (0.02 meter) and outflow water temperature to within 1.08 °F (0.60 °C). Streamflow, water temperature, and lake elevation data collected during summer 2014 supplied the boundary and reference conditions for the model. Measured discrepancies between outflow and inflow from the lake, assumed to be mostly from unknown and diffuse springs under the lake, accounted for about 46 percent of the total inflow to the lake. Model simulations (scenarios) were run with lower water surface elevations in Crystal Springs Lake and increased shading to the lake to assess the relative effect the lake and pond characteristics have on water temperature. The Golf Pond was unaltered in all scenarios. The models estimated that lower lake elevations would result in cooler water downstream of the Golf Pond and shorter residence times in the lake. Increased shading to the lake would also provide substantial cooling. Most management scenarios resulted in a decrease in 7-day average of daily maximum values by about 2.0– 4.7 °F (1.1 –2.6 °C) for outflow from Crystal Springs Lake during the period of interest. Outflows from the Golf Pond showed a net temperature reduction of 0.5–2.7 °F (0.3–1.5 °C) compared to measured values in 2014 because of solar heating and downstream warming in the Golf Pond resulting from mixing with inflow from Reed Lake.

Oregon↗

USGS2016

Simulating future water temperatures in the North Santiam River, Oregon

A previously calibrated two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Detroit Lake in western Oregon was used in conjunction with inflows derived from Precipitation-Runoff Modeling System (PRMS) hydrologic models to examine in-lake and downstream water temperature effects under future climate conditions. Current and hypothetical operations and structures at Detroit Dam were imposed on boundary conditions derived from downscaled General Circulation Models in base (1990–1999) and future (2059–2068) periods. Compared with the base period, future air temperatures were about 2 °C warmer year-round. Higher air temperature and lower precipitation under the future period resulted in a 23% reduction in mean annual PRMS-simulated discharge and a 1 °C increase in mean annual estimated stream temperatures flowing into the lake compared to the base period. Simulations incorporating current operational rules and minimum release rates at Detroit Dam to support downstream habitat, irrigation, and water supply during key times of year resulted in lower future lake levels. That scenario results in a lake level that is above the dam’s spillway crest only about half as many days in the future compared to historical frequencies. Managing temperature downstream of Detroit Dam depends on the ability to blend warmer water from the lake’s surface with cooler water from deep in the lake, and the spillway is an important release point near the lake’s surface. Annual average in-lake and release temperatures from Detroit Lake warmed 1.1 °C and 1.5 °C from base to future periods under present-day dam operational rules and fill schedules. Simulated dam operations such as beginning refill of the lake 30 days earlier or reducing minimum release rates (to keep more water in the lake to retain the use of the spillway) mitigated future warming to 0.4 and 0.9 °C below existing operational scenarios during the critical autumn spawning period for endangered salmonids. A hypothetical floating surface withdrawal at Detroit Dam improved temperature control in summer and autumn (0.6 °C warmer in summer, 0.6 °C cooler in autumn compared to existing structures) without altering release rates or lake level management rules.

Oregon↗

USGS2015

Development of a HEC-RAS temperature model for the North Santiam River, northwestern Oregon

A one-dimensional, unsteady streamflow and temperature model (HEC-RAS) of the North Santiam and Santiam Rivers was developed by the U.S. Geological Survey to be used in conjunction with previously developed two-dimensional hydrodynamic water-quality models (CE-QUAL-W2) of Detroit and Big Cliff Lakes upstream of the study area. In conjunction with the output from the previously developed models, the HEC-RAS model can simulate streamflows and temperatures within acceptable limits (mean error [bias] near zero; typical streamflow errors less than 5 percent; typical water temperature errors less than 1.0 °C) for the length of the North Santiam River downstream of Big Cliff Dam under a series of potential future conditions in which dam structures and/or dam operations are modified to improve temperature conditions for threatened and endangered fish. Although a two-dimensional (longitudinal, vertical) CE-QUAL-W2 model for the North Santiam and Santiam Rivers downstream of Big Cliff Dam exists, that model proved unstable under highly variable flow conditions. The one-dimensional HEC-RAS model documented in this report can better simulate cross-sectional-averaged stream temperatures under a wide range of flow conditions. The model was calibrated using 2011 streamflow and temperature data. Measured data were used as boundary conditions when possible, although several lateral inflows and their associated water temperatures, including the South Santiam River, were estimated using statistical models. Streamflow results showed high accuracy during low-flow periods, but predictions were biased low during large storm events when unmodeled ephemeral tributaries contributed to the actual streamflow. Temperature results showed low annual bias against measured data at two locations on the North Santiam River and one location on the Santiam River. Mean absolute errors using 2011 hourly data ranged from 0.4 to 0.7 °C. Model results were checked against 2012 data and showed a positive bias at the Santiam River station (+0.6 ˚C). Annual mean absolute errors using 2012 hourly data ranged from 0.4 to 0.8 °C. Much of the error in temperature predictions resulted from the model’s inability to accurately simulate the full range of diurnal fluctuations during the warmest months. Future iterations of the model could be improved by the collection and inclusion of additional streamflow and temperature data, especially near the mouth of the South Santiam River. Presently, the model is able to predict hourly and daily water temperatures under a wide variety of conditions with a typical error of 0.8 and 0.7 °C, respectively.

Oregon↗

USGS2015

Simulations of a hypothetical temperature control structure at Detroit Dam on the North Santiam River, northwestern Oregon

Water temperature models of Detroit Lake, Big Cliff Lake, and the North Santiam River in northwestern Oregon were used to assess the potential for a hypothetical structure with variable intake elevations and an internal connection to power turbines at Detroit Dam (scenario SlidingWeir ) to release more natural, pre-dam temperatures year round. This hypothetical structure improved outflow temperature control from Detroit Dam while meeting minimum dry-season release rates and lake levels specified by the rule curve specified for Detroit Lake. A water temperature target based on long-term, without-dams temperature estimates was developed and used to guide the Detroit Lake model to blend releases from the user-defined outlets at Detroit Dam. Simulations that included warm surface water releases during the spring and summer, and cool, deep hypolimnetic water releases later during autumn typically met the temperature target. Immediately downstream of Detroit Dam, these simulations resulted in temperatures within the range of the without-dams temperature estimates for most of the year until about November. The minimum release rates of flow imposed at Detroit Dam during late summer and early autumn exceeded unregulated, without-dams flow estimates. This higher flow led to temperatures near the low end of the without-dams temperature range 46.3 river miles downstream at Greens Bridge from July to September; the high flows released from Detroit Dam were less susceptible to downstream warming than the low unregulated flows. Simulations that blended warm and cool water from different outlets at Detroit Dam resulted in less daily temperature variation compared to the without-dams scenarios as far downstream as Greens Bridge. Estimated egg-emergence days for endangered Upper Willamette River Chinook salmon ( Oncorhynchus tshawytscha ) and Upper Willamette River winter steelhead ( Oncorhynchus mykiss ) were assessed for all scenarios. Estimated spring Chinook fry emergence under SlidingWeir scenarios was 9 days later immediately downstream of Big Cliff Dam, and 4 days later at Greens Bridge compared with existing structural scenarios at Detroit Dam. Despite the inclusion of a hypothetical sliding weir at Detroit Dam, temperatures exceeded without-dams temperatures during November and December. These late-autumn exceedances likely represent the residual thermal effect of Detroit Lake operated to meet minimum dry-season release rates (supporting instream habitat and irrigation requirements) and lake levels specified by the current (2014) operating rules (supporting recreation and flood mitigation).

Oregon↗

USGS2015

Improved algorithms in the CE-QUAL-W2 water-quality model for blending dam releases to meet downstream water-temperature targets

Water-quality models allow water resource professionals to examine conditions under an almost unlimited variety of potential future scenarios. The two-dimensional (longitudinal, vertical) water-quality model CE-QUAL-W2, version 3.7, was enhanced and augmented with new features to help dam operators and managers explore and optimize potential solutions for temperature management downstream of thermally stratified reservoirs. Such temperature management often is accomplished by blending releases from multiple dam outlets that access water of different temperatures at different depths. The modified blending algorithm in version 3.7 of CE-QUAL-W2 allows the user to specify a time-series of target release temperatures, designate from 2 to 10 floating or fixed-elevation outlets for blending, impose minimum and maximum head and flow constraints for any blended outlet, and set priority designations for each outlet that allow the model to choose which outlets to use and how to balance releases among them. The modified model was tested with a variety of examples and against a previously calibrated model of Detroit Lake on the North Santiam River in northwestern Oregon, and the results compared well. These updates to the blending algorithms will allow more complicated dam-operation scenarios to be evaluated somewhat automatically with the model, with decreased need for multiple model runs or preprocessing of model inputs to fully characterize the operational constraints.

Open-File Report↗

USGS2013

Development of CE-QUAL-W2 models for the Middle Fork Willamette and South Santiam Rivers, Oregon

Hydrodynamic (CE-QUAL-W2) models of Hills Creek Lake (HCL), Lookout Point Lake (LOP), and Dexter Lake (DEX) on the Middle Fork Willamette River (MFWR), and models of Green Peter Lake and Foster Lake on the South Santiam River systems in western Oregon were updated and recalibrated for a wide range of flow and meteorological conditions. These CE-QUAL-W2 models originally were developed by West Consultants, Inc., for the U.S. Army Corps of Engineers. This study by the U.S. Geological Survey included a reassessment of the models’ calibration in more recent years—2002, 2006, 2008, and 2011—categorized respectively as low, normal, high, and extremely high flow calendar years. These years incorporated current dam-operation practices and more available data than the time period used in the original calibration. Modeled water temperatures downstream of both HCL and LOP-DEX on the MFWR were within an average of 0.68 degree Celsius (°C) of measured values; modeled temperatures downstream of Foster Dam on the South Santiam River were within an average of 0.65°C of measured values. A new CE-QUAL-W2 model was developed and calibrated for the riverine MFWR reach between Hills Creek Dam and the head of LOP, allowing an evaluation of the flow and temperature conditions in the entire MFWR system from HCL to Dexter Dam. The complex bathymetry and long residence time of HCL, combined with the relatively deep location of the power and regulating outlet structures at Hills Creek Dam, led to a HCL model that was highly sensitive to several outlet and geometric parameters related to dam structures (STR TOP, STR BOT, STR WIDTH). Release temperatures from HCL were important and often persisted downstream as they were incorporated in the MFWR model and the LOP-DEX model (downstream of MFWR). The models tended to underpredict the measured temperature of water releases from Dexter Dam during the late-September-through-December drawdown period in 2002, and again (to a lesser extent) in 2011, but simulations were much more accurate in 2006 and 2008. This episodic model bias may have been a result of hot, dry conditions; lower lake elevations; and earlier drawdown at both HCL and LOP in 2002. These dry conditions in 2002 may have contradicted assumptions inherent in the estimation of certain model inputs, such as unmeasured inflows and water temperatures, which may respond differently during dry years than during normal and wet years. This report documents the development and calibration of new and revised flow and water-temperature models for riverine and reservoir reaches in the Middle Fork Willamette River and South Santiam River systems. Methods and model parameter values were established for the accurate simulation of flows and temperatures in these systems under current conditions. By extension, these models should be able to accurately simulate flows and temperatures under potential future conditions in which dam operations and dam outlet structures may be changed as part of a strategy to improve habitat, fish passage, and temperature conditions for endangered fish.

Oregon↗

USGS2012

Dispersal of larval suckers at the Williamson River Delta, Upper Klamath Lake, Oregon, 2006-09

An advection/diffusion modeling approach was used to simulate the transport of larval suckers from spawning areas in the Williamson River, through the newly restored Williamson River Delta, to Upper Klamath Lake. The density simulations spanned the years of phased restoration, from 2006/2007 prior to any levee breaching, to 2008 when the northern part of the delta was reconnected to the lake, and 2009 when levees on both sides of the delta had been breached. Model simulation results from all four years were compared to field data using rank correlation. Spearman ρ correlation coefficients were usually significant and in the range 0.30 to 0.60, providing moderately strong validation of the model. The correlation coefficients varied with fish size class in a way that suggested that the model best described the distribution of smaller fish near the Williamson River channel, and larger fish away from the channel. When Lost River and shortnose/Klamath largescale suckers were simulated independently, the correlation results suggested that the model better described the transport and dispersal of the latter species. The incorporation of night-time-only drift behavior in the Williamson River channel neither improved nor degraded correlations with field data. The model showed that advection by currents is an important factor in larval dispersal.

Oregon↗

USGS2012

Simulating potential structural and operational changes for Detroit Dam on the North Santiam River, Oregon, for downstream temperature management

Detroit Dam was constructed in 1953 on the North Santiam River in western Oregon and resulted in the formation of Detroit Lake. With a full-pool storage volume of 455,100 acre-feet and a dam height of 463 feet, Detroit Lake is one of the largest and most important reservoirs in the Willamette River basin in terms of power generation, recreation, and water storage and releases. The U.S. Army Corps of Engineers operates Detroit Dam as part of a system of 13 reservoirs in the Willamette Project to meet multiple goals, which include flood-damage protection, power generation, downstream navigation, recreation, and irrigation. A distinct cycle in water temperature occurs in Detroit Lake as spring and summer heating through solar radiation creates a warm layer of water near the surface and isolates cold water below. Controlling the temperature of releases from Detroit Dam, therefore, is highly dependent on the location, characteristics, and usage of the dam's outlet structures. Prior to operational changes in 2007, Detroit Dam had a well-documented effect on downstream water temperature that was problematic for endangered salmonid fish species, releasing water that was too cold in midsummer and too warm in autumn. This unnatural seasonal temperature pattern caused problems in the timing of fish migration, spawning, and emergence. In this study, an existing calibrated 2-dimensional hydrodynamic water-quality model [CE-QUAL-W2] of Detroit Lake was used to determine how changes in dam operation or changes to the structural release points of Detroit Dam might affect downstream water temperatures under a range of historical hydrologic and meteorological conditions. The results from a subset of the Detroit Lake model scenarios then were used as forcing conditions for downstream CE-QUAL-W2 models of Big Cliff Reservoir (the small reregulating reservoir just downstream of Detroit Dam) and the North Santiam and Santiam Rivers. Many combinations of environmental, operational, and structural options were explored with the model scenarios. Multiple downstream temperature targets were used along with three sets of environmental forcing conditions representing cool/wet, normal, and hot/dry conditions. Five structural options at Detroit Dam were modeled, including the use of existing outlets, one hypothetical variable-elevation outlet such as a sliding gate, a hypothetical combination of a floating outlet and a fixed-elevation outlet, and a hypothetical combination of a floating outlet and a sliding gate. Finally, 14 sets of operational guidelines for Detroit Dam were explored to gain an understanding of the effects of imposing different downstream minimum streamflows, imposing minimum outflow rules to specific outlets, and managing the level of the lake with different timelines through the year. Selected subsets of these combinations of operational and structural scenarios were run through the downstream models of Big Cliff Reservoir and the North Santiam and Santiam Rivers to explore how hypothetical changes at Detroit Dam might provide improved temperatures for endangered salmonids downstream of the Detroit-Big Cliff Dam complex. Conclusions that can be drawn from these model scenarios include: *The water-temperature targets set by the U.S. Army Corps of Engineers for releases from Detroit Dam can be met through a combination of new dam outlets or a delayed drawdown of the lake in autumn. *Spring and summer dam operations greatly affect the available release temperatures and operational flexibility later in the autumn. Releasing warm water during midsummer tends to keep more cool water available for release in autumn. *The ability to meet downstream temperature targets during spring depends on the characteristics of the available outlets. Under existing conditions, although warm water sometimes is present at the lake surface in spring and early summer, such water may not be available for release if the lake level is either well below or well above the spillway crest. *Managing lake releases to meet downstream temperature targets depends on having outlet structures that can access both (warm) lake surface water and (cold) deeper lake water throughout the year. The existing outlets at Detroit Dam do not allow near-surface waters to be released during times when the lake surface level is below the spillway (spring and autumn). *Using the existing outlets at Detroit Dam, lake level management is important to the water temperature of releases because it controls the availability and depth of water at the spillway. When lake level is lowered below the spillway crest in late summer, the loss of access to warm water at the lake surface can result in abrupt changes to release temperatures. *Because the power-generation intakes (penstocks) are 166 feet below the full-pool lake level, imposing minimum power production requirements at Detroit Dam limits the amount of warm surface water that can be expelled from the lake in midsummer, thereby postponing and amplifying warm outflows from Detroit Lake into the autumn spawning season. *Likewise, imposing minimum power production requirements at Detroit Dam in autumn can limit the amount of cool hypolimnetic water that is released from the lake, thereby limiting cool outflows from Detroit Lake during the autumn spawning season. *Model simulations indicate that a delayed drawdown of Detroit Lake in autumn would result in better control over release temperatures in the immediate downstream vicinity of Big Cliff Dam, but the reduced outflows necessary to retain more water in the lake in late summer are more susceptible to rapid heating downstream. *Compared to the existing outlets at Detroit Dam, floating or sliding-gate outlet structures can provide greater control over release temperatures because they provide better access to warm water at the lake surface and cooler water at depth. These conclusions can be grouped into several common themes. First, optimal and flexible management and achievement of downstream temperature goals requires that releases of warm water near the surface of the lake and cold water below the thermocline are both possible with the available dam outlets during spring, summer, and autumn. This constraint can be met to some extent with existing outlets, but only if access to the spillway is extended into autumn by keeping the lake level higher than called for by the current rule curve (the typical target water-surface elevation throughout the year). If new outlets are considered, a variable-elevation outlet such as a sliding gate structure, or a floating outlet in combination with a fixed-elevation outlet at sufficient depth to access cold water, is likely to work well in terms of accessing a range of water temperatures and achieving downstream temperature targets. Furthermore, model results indicate that it is important to release warm water from near the lake surface during midsummer. If not released downstream, the warm water will build up at the top of the lake as a result of solar energy inputs and the thermocline will deepen, potentially causing warm water to reach the depth of deeper fixed-elevation outlets in autumn, particularly when the lake level is drawn down to make room for flood storage. Delaying the drawdown in autumn can help to keep the thermocline above such outlets and preserve access to cold water. Although it is important to generate hydropower at Detroit Dam, minimum power-production requirements limit the ability of dam operators to meet downstream temperature targets with existing outlet structures. The location of the power penstocks below the thermocline in spring and most of summer causes the release of more cool water during summer than is optimal. Reducing the power-production constraint allows the temperature target to be met more frequently, but at the cost of less power generation. Finally, running the Detroit Dam, Big Cliff Dam, and North Santiam and Santiam River models in series allows dam operators to evaluate how different operational strategies or combinations of new dam outlets might affect downstream temperatures for many miles of critical endangered salmonid habitat. Temperatures can change quickly in these downstream reaches as the river exchanges heat with its surroundings, and heating or cooling of 6 degrees Celsius is not unusual in the 40–50 miles downstream of Big Cliff Dam. The results published in this report supersede preliminary results published in U.S. Geological Survey Open-File Report 2011-1268 (Buccola and Rounds, 2011). Those preliminary results are still valid, but the results in this report are more current and comprehensive.

Oregon↗

USGS2011

Simulating potential structural and operational changes for Detroit Dam on the North Santiam River, Oregon-Interim Results

Prior to operational changes in 2007, Detroit Dam on the North Santiam River in western Oregon had a well-documented effect on downstream water temperature that was problematic for endangered salmonid fish species. In this U.S. Geological Survey study, done in cooperation with the U.S. Army Corps of Engineers, an existing calibrated CE-QUAL-W2 model of Detroit Lake (the impounded waterbody behind Detroit Dam) was used to determine how changes in dam operation or changes to the structural release points of Detroit Dam might affect downstream water temperatures under a range of historical hydrologic and meteorological conditions. Many combinations of environmental, operational, and structural options were explored with the model. Two downstream temperature targets were used along with three sets of environmental forcing conditions representing normal, hot/dry, and cool/wet conditions. Three structural options were modeled, including the use of existing outlets, one hypothetical variable-elevation outlet such as a sliding gate, and a hypothetical combination of a floating outlet and a fixed-elevation outlet. Finally, four sets of operational guidelines were explored to gain an understanding of the effects of imposing different downstream minimum streamflows or managing the level of the lake with different timelines in autumn. Several conclusions can be made from these interim model scenarios: * Temperature targets just downstream of Detroit Dam can be met through a combination of new dam outlets or a delayed drawdown of the lake in autumn. * Spring and summer dam operations greatly affect the available release temperatures and operational flexibility later in the autumn. Releasing warm water during mid-summer tends to keep more cool water available for release in autumn. * The ability to meet downstream temperature targets during spring depends on the characteristics of the available outlets. Under existing conditions, for example, although warm water sometimes is present at the lake surface, such water may not be available for release if the lake level is either well below or well above the spillway crest in spring and early summer. * Managing lake releases to meet downstream temperature targets depends on having outlet structures that can access both (warm) lake surface water and (cold) deeper lake water throughout the year. The existing outlets at Detroit Dam do not allow near-surface waters to be released during times when the lake surface level is below the spillway (spring and autumn). * Model simulations indicate that delayed drawdown of Detroit Lake in autumn would result in better control over release temperatures. * Compared to the existing outlets at Detroit Dam, floating or sliding-gate outlet structures can provide greater control over release temperatures because they provide better access to warm water at the lake surface and cooler water at depth. This report provides interim study results to the U.S. Army Corps of Engineers. The full study will be completed in 2012.

Open-File Report↗

USGS2010

Empirical models of wind conditions on Upper Klamath Lake, Oregon

Upper Klamath Lake is a large (230 square kilometers), shallow (mean depth 2.8 meters at full pool) lake in southern Oregon. Lake circulation patterns are driven largely by wind, and the resulting currents affect the water quality and ecology of the lake. To support hydrodynamic modeling of the lake and statistical investigations of the relation between wind and lake water-quality measurements, the U.S. Geological Survey has monitored wind conditions along the lakeshore and at floating raft sites in the middle of the lake since 2005. In order to make the existing wind archive more useful, this report summarizes the development of empirical wind models that serve two purposes: (1) to fill short (on the order of hours or days) wind data gaps at raft sites in the middle of the lake, and (2) to reconstruct, on a daily basis, over periods of months to years, historical wind conditions at U.S. Geological Survey sites prior to 2005. Empirical wind models based on Artificial Neural Network (ANN) and Multivariate-Adaptive Regressive Splines (MARS) algorithms were compared. ANNs were better suited to simulating the 10-minute wind data that are the dependent variables of the gap-filling models, but the simpler MARS algorithm may be adequate to accurately simulate the daily wind data that are the dependent variables of the historical wind models. To further test the accuracy of the gap-filling models, the resulting simulated winds were used to force the hydrodynamic model of the lake, and the resulting simulated currents were compared to measurements from an acoustic Doppler current profiler. The error statistics indicated that the simulation of currents was degraded as compared to when the model was forced with observed winds, but probably is adequate for short gaps in the data of a few days or less. Transport seems to be less affected by the use of the simulated winds in place of observed winds. The simulated tracer concentration was similar between model results when simulated winds were used to force the model, and when observed winds were used to force the model, and differences between the two results did not accumulate over time.

Scientific Investigations Report↗