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USGS2024

Testing food web theory in a large lake: The role of body size in habitat coupling in Lake Michigan

The landscape theory of food web architecture (LTFWA) describes relationships among body size, trophic position, mobility, and energy channels that serve to couple heterogenous habitats, which in turn promotes long-term system stability. However, empirical tests of the LTFWA are rare and support differs among terrestrial, freshwater, and marine systems. Further, it is unclear whether the theory applies in highly altered ecosystems dominated by introduced species such as the Laurentian Great Lakes. Here, we provide an empirical test of the LTFWA by relating body size, trophic position, and the coupling of different energy channels using stable isotope data from species throughout the Lake Michigan food web. We found that body size was positively related to trophic position, but for a given trophic position, organisms predominately supported by pelagic energy had smaller body sizes than organisms predominately supported by nearshore benthic energy. We also found a hump-shaped trophic relationship in the food web where there is a gradual increase in the coupling of pelagic and nearshore energy channels with larger body sizes as well as higher trophic positions. This highlights the important role of body size and connectivity among habitats in structuring food webs. However, important deviations from expectations are suggestive of how species introductions and other anthropogenic impacts can affect food web structure in large lakes. First, native top predators appear to be flexible couplers that may provide food web resilience, whereas introduced top predators may confer less stability when they specialize on a single energy pathway. Second, some smaller bodied prey fish and invertebrates, in addition to mobile predators, coupled energy from pelagic and nearshore energy channels, which suggests that some prey species may also be important integrators of energy pathways in the system. We conclude that patterns predicted by the LTFWA are present in the face of species introductions and other anthropogenic stressors to a degree, but time-series evaluations are needed to fully understand the mechanisms that promote stability.

Lake Michigan↗

USGS2016

Multi-scale connectivity and graph theory highlight critical areas for conservation under climate change

Conservation planning and biodiversity management require information on landscape connectivity across a range of spatial scales from individual home ranges to large regions. Reduction in landscape connectivity due changes in land-use or development is expected to act synergistically with alterations to habitat mosaic configuration arising from climate change. We illustrate a multi-scale connectivity framework to aid habitat conservation prioritization in the context of changing land use and climate. Our approach, which builds upon the strengths of multiple landscape connectivity methods including graph theory, circuit theory and least-cost path analysis, is here applied to the conservation planning requirements of the Mohave ground squirrel. The distribution of this California threatened species, as for numerous other desert species, overlaps with the proposed placement of several utility-scale renewable energy developments in the American Southwest. Our approach uses information derived at three spatial scales to forecast potential changes in habitat connectivity under various scenarios of energy development and climate change. By disentangling the potential effects of habitat loss and fragmentation across multiple scales, we identify priority conservation areas for both core habitat and critical corridor or stepping stone habitats. This approach is a first step toward applying graph theory to analyze habitat connectivity for species with continuously-distributed habitat, and should be applicable across a broad range of taxa.

Ecological Applications↗

USGS2010

Application of the Systems Impact Assessment Model (SIAM) to fishery resource issues in the Klamath River, California

At the request of two offices of the U.S. Fish and Wildlife Service (FWS) located in Yreka and Arcata, Calif., we applied the Systems Impact Assessment Model (SIAM) to analyze a variety of water management concerns associated with the Federal Energy Regulatory Commission (FERC) relicensing of the Klamath hydropower projects or with ongoing management of anadromous fish stocks in the mainstem Klamath River, Oregon and California. Requested SIAM analyses include predicted effects of reservoir withdrawal elevations, use of full active storage in Copco and Iron Gate Reservoirs to augment spring flows, and predicted spawning and juvenile outmigration timing of fall Chinook salmon. In an effort to further refine the analysis of spring flow effects on predicted fall Chinook production, additional SIAM analyses were performed for predicted response to spring flow release variability from Iron Gate Dam, high and low pulse flow releases, the predicted effects of operational constraints for both Upper Klamath Lake water surface elevations, and projected flow releases specified in the Klamath Project 2006 Operations Plan (April 10, 2006). Results of SIAM simulations to determine flow and water temperature relationships indicate that up to 4 degrees C of thermal variability can be attributed to flow variations, but the effect is seasonal. Much more of thermal variability can be attributed to air temperature variations, up to 6 degrees C. Reservoirs affect the annual thermal signature by delaying spring warming by about 3 weeks and fall cooling by about 2 weeks. Multi-level release outlets on Iron Gate Dam would have limited utility; however, if releases are small (700 cfs) and a near-surface and bottom-level outlet could be blended, then water temperature may be reduced by 2-4 degrees C for a 4-week period during September. Using the full active storage in Copco and Iron Gate Reservoir, although feasible, had undesirable ramifications such as earlier spring warming, loss of hydropower production, and inability to re-fill the reservoirs without causing shortages elsewhere in the system. Altering spawning and outmigration timing may be important management objectives for the salmon fishery, but difficult to implement. SIAM predicted benefits that might occur if water temperature was cooler in fall and spring emergence was advanced; however, model simulations were based on purely arbitrary thermal reductions. Spring flow variability did indicate that juvenile fall Chinook rearing habitat was the major biological 'bottleneck' for year class success. Rearing habitat is maximal in a range between 4,500 and 5,500 cfs below Iron Gate Dam. These flow levels are not typically provided by Klamath River system operations, except in very wet years. The incremental spring flow analysis provided insight into when and how long a pulse flow should occur to provide predicted fall Chinook salmon production increases. In general, March 15th - April 30th of any year was the period for pulse flows and 4000 cfs was the target flow release that provided near-optimal juvenile rearing habitat. Again, competition for water resources in the Klamath River Basin may make implementation of pulsed flows difficult.

California, Oregon↗

USGS2018

Geometric versus anemometric surface roughness for a shallow accumulating snowpack

When applied to a snow-covered surface, aerodynamic roughness length, z 0 , is typically considered as a static parameter within energy balance equations. However, field observations show that z 0 changes spatially and temporally, and thus z 0 incorporated as a dynamic parameter may greatly improve models. To evaluate methods for characterizing snow surface roughness, we compared concurrent estimates of z 0 based on (1) terrestrial light detection and ranging derived surface geometry of the snowpack surface (geometric, z 0 G ) and (2) vertical wind profile measurements (anemometric, z 0 A ). The value of z 0 G was computed from Lettau’s equation and underestimated z 0 A but compared well when scaled by a factor of 2.34. The Counihan method for computing z 0 G was found to be unsuitable for estimating z 0 on a snow surface. During snowpack accumulation in early winter, z 0 varied as a function of the snow-covered area (SCA). Our results show that as the SCA increases, z 0 decreases, indicating there is a topographic influence on this relation.

Geosciences↗

USGS2015

Bioenergetics modeling of percid fishes

A bioenergetics model for a percid fish represents a quantitative description of the fish’s energy budget. Bioenergetics modeling can be used to identify the important factors determining growth of percids in lakes, rivers, or seas. For example, bioenergetics modeling applied to yellow perch ( Perca flavescens ) in the western and central basins of Lake Erie revealed that the slower growth in the western basin was attributable to limitations in suitably sized prey in western Lake Erie, rather than differences in water temperature between the two basins. Bioenergetics modeling can also be applied to a percid population to estimate the amount of food being annually consumed by the percid population. For example, bioenergetics modeling applied to the walleye ( Sander vitreus ) population in Lake Erie has provided fishery managers valuable insights into changes in the population’s predatory demand over time. In addition, bioenergetics modeling has been used to quantify the effect of the difference in growth between the sexes on contaminant accumulation in walleye. Field and laboratory evaluations of percid bioenergetics model performance have documented a systematic bias, such that the models overestimate consumption at low feeding rates but underestimate consumption at high feeding rates. However, more recent studies have shown that this systematic bias was due, at least in part, to an error in the energy budget balancing algorithm used in the computer software. Future research work is needed to more thoroughly assess the field and laboratory performance of percid bioenergetics models and to quantify differences in activity and standard metabolic rate between the sexes of mature percids.

Book chapter↗

USGS2020

Using saline or brackish aquifers as reservoirs for thermal energy storage, with example calculations for direct-use heating in the Portland Basin, Oregon, USA

Tools to evaluate reservoir thermal energy storage (RTES; heat storage in slow-moving or stagnant geochemically evolved permeable zones in strata that underlie well-connected regional aquifers) are developed and applied to the Columbia River Basalt Group (CRBG) beneath the Portland Basin, Oregon, USA. The performance of RTES for heat storage and recovery in the Portland Basin is strongly dependent on the operational schedule of heat injection and extraction. We examined the effects of the operational schedule, based on an annual solar hot water supply pattern and a building heating demand model, using heat and fluid flow simulations with SUTRA. We show RTES to be feasible for supply of heating energy for a large combined research/teaching building on the Oregon Health and Science University South Waterfront expansion, an area of planned future development. Initially, heat is consumed to increase the reservoir temperature, and conductive heat loss is high due to high temperature gradients between the reservoir and surrounding rock. Conductive heat loss continues into the future, but the rate of heat loss decreases, and heat recovery efficiency of the RTES system increases over time. Simulations demonstrate the effects of varying heat-delivery rate and temperature on the heat production history of the reservoir. If 100% of building heating needs are to be supplied by combined solar/RTES, then the solar system must be sized to meet building needs plus long-term thermal losses (i.e., conductive losses once the system is heated to pseudo-steady state) from the RTES system. If the solar heating system barely meets these criteria, then during early years, less than 100% of the building demand will be supplied until the reservoir is fully-heated. The duration of supplying less than 100% of building demand can be greatly shortened by pre-heating the reservoir before building heating operations or by adding extra heat from external sources during early years. Analytic solutions are developed to evaluate efficacy and to help design RTES systems (e.g., well-spacing, thermal source sizing, etc.). A map of thermal energy storage capacity is produced for the CRBG beneath the Portland Basin. The simulated building has an annual heat load of ∼1.9 GWh, and the total annual storage capacity of the Portland Basin is estimated to be 43,400 GWh assuming seasonal storage of heat yields water from which 10 °C can be extracted via heat exchange, indicating a tremendous heating capacity of the CRBG.

Oregon↗

USGS2010

A probabilistic assessment methodology for the evaluation of geologic carbon dioxide storage

In 2007, the Energy Independence and Security Act (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of potential geologic storage resources for carbon dioxide (CO 2 ) in cooperation with the U.S. Environmental Protection Agency and the U.S. Department of Energy. The first year of that activity was specified for development of a methodology to estimate storage potential that could be applied uniformly to geologic formations across the United States. After its release, the methodology was to receive public comment and external expert review. An initial methodology was developed and published in March 2009 (Burruss and others, 2009), and public comments were received. The report was then sent to a panel of experts for external review. The external review report was received by the USGS in December 2009. This report is in response to those external comments and reviews and describes how the previous assessment methodology (Burruss and others, 2009) was revised. The resource that is assessed is the technically accessible storage resource, which is defined as the mass of CO 2 that can be stored in the pore volume of a storage formation. The methodology that is presented in this report is intended to be used for assessments at scales ranging from regional to subbasinal in which storage assessment units are defined on the basis of common geologic and hydrologic characteristics. The methodology does not apply to site-specific evaluation of storage resources or capacity.

Open-File Report↗

USGS2018

Minimum energy requirements for desalination of brackish groundwater in the United States with comparison to international datasets

This paper uses chemical and physical data from a large 2017 U.S. Geological Survey groundwater dataset with wells in the U.S. and three smaller international groundwater datasets with wells primarily in Australia and Spain to carry out a comprehensive investigation of brackish groundwater composition in relation to minimum desalination energy costs. First, we compute the site-specific least work required for groundwater desalination. Least work of separation represents a baseline for specific energy consumption of desalination systems. We develop simplified equations based on the U.S. data for least work as a function of water recovery ratio and a proxy variable for composition, either total dissolved solids, specific conductance, molality or ionic strength. We show that the U.S. correlations for total dissolved solids and molality may be applied to the international datasets. We find that total molality can be used to calculate the least work of dilute solutions with very high accuracy. Then, we examine the effects of groundwater solute composition on minimum energy requirements , showing that separation requirements increase from calcium to sodium for cations and from sulfate to bicarbonate to chloride for anions , for any given TDS concentration. We study the geographic distribution of least work, total dissolved solids, and major ions concentration across the U.S. We determine areas with both low least work and high water stress in order to highlight regions holding potential for desalination to decrease the disparity between high water demand and low water supply. Finally, we discuss the implications of the USGS results on water resource planning, by comparing least work to the specific energy consumption of brackish water reverse osmosis plants and showing the scaling propensity of major electrolytes and silica in the U.S. groundwater samples.

Water Research↗

USGS2023

Crop water use dynamics over arid and semi-arid croplands in the lower Colorado River Basin

Numerous studies have evaluated the application of Remote Sensing (RS) techniques for mapping actual evapotranspiration (ETa) using Vegetation-Index-based (VI-based) and surface energy balance methods (SEB). SEB models computationally require a large effort for application. VI-based methods are fast and easy to apply and could therefore potentially be applied at high resolution; however, the accuracy of VI-based methods in comparison to SEB-based models remains unclear. We tested the ETa computed with the modified 2-band Enhanced Vegetation Index (METEVI2) implemented in the Google Earth Engine – for mapping croplands’ water use dynamics in the Lower Colorado River Basin. We compared METEVI2 with the well-established RS-based products of OpenET (Ensemble, eeMETRIC, SSEBop, SIMS, PT_JPL, DisALEXI and geeSEBAL). METEVI2 was then evaluated with measured ETa from four wheat fields (2017–2018). Results indicated that the monthly ETa variations for METEVI2 and OpenET models were comparable, though of varying magnitudes. On average, METEVI2 had the lowest difference rate from the average observed ETa with 17 mm underestimation, while SIMS had the highest difference rate (82 mm). Findings show that METEVI2 is a cost-effective ETa mapping tool in drylands to track crop water use. Future studies should test METEVI2’s applicability to croplands in more humid regions.

Lower Colorado River basin↗

USGS1984

Irrigation data from Chase, Dundy, and Perkins Counties, southwestern Nebraska, 1983

This report summarizes data collected by the U.S. Geological Survey in Chase, Dundy, and Perkins Counties, southwest Nebraska. It includes data collected from 52 randomly selected wells that were monitored during the 1983 irrigation season to obtain measurements of discharge and the rate of energy consumption. The data were collected as part of a study to better define the relationship between pumpage and return flow from applied water. (USGS)

Open-File Report↗

USGS2018

Conceptual model to assess water use associated with the life cycle of unconventional oil and gas development

As the demand for energy increases in the United States, so does the demand for water used to produce many forms of that energy. Technological advances, limited access to conventional oil and gas accumulations, and the rise of oil and gas prices resulted in increased development of unconventional oil and gas (UOG) accumulations. Unconventional oil and gas is developed using a method that combines directional drilling and hydraulic fracturing techniques, allowing for greater oil and gas production from previously unrecoverable reservoirs. Quantification of the water resources required for UOG development and production is difficult because of disparate data sources, variable reporting requirements across boundaries (local, State, and national), and incomplete or proprietary datasets. A topical study was started in 2015 under the U.S. Geological Survey’s Water Availability and Use Science Program, as part of the directive in the Secure Water Act for the U.S. Geological Survey to conduct a National Water Census, to better understand the relation between production of UOG resources for energy and the amount of water needed to produce and sustain this type of energy development in the United States. The Water Availability and Use Science Program goal for this topical study is to develop and apply a statistical model to better estimate the water use associated with UOG development, regardless of the location and target geologic formation. As a first step, a conceptual model has been developed to characterize the life cycle of water use in areas of UOG development. Categories of water use and the way water-use data are collected might change over time; therefore, a generic approach was used in developing the conceptual model to allow for greater flexibility in adapting to future changes or newly available data. UOG development can be summarized into four stages: predrilling construction, drilling, hydraulic fracturing, and ongoing production. The water used in UOG production can be categorized further as direct, indirect, or ancillary water use. Direct water use is defined as the water used for drilling and hydraulic fracturing a well and for maintaining the well during ongoing production. Indirect water use is defined as the water used at or near a well pad. The water used for dust abatement also is considered an indirect use but may be applied away from the well pad. Ancillary water use is defined as the additional local or regional water use resulting from a change (for example, population) directly related to UOG development throughout the life cycle that is not used directly in the well or indirectly for any other purpose at the well pad. The conceptual model presented in this report consists of five elements: (1) input data, (2) processes, (3) decisions, (4) output data, and (5) outcomes. The input data requirements for estimating water use associated with UOG development are somewhat onerous, and obtaining suitable datasets can be challenging because local, State, and Federal agencies do not collect data similarly. The quality of a water-use assessment that uses the conceptual model presented in this report is dependent on the quality and quantity of data that are available for a UOG play. The conceptual model can be used for an assessment with sparse data; however, having sparse data likely will result in greater uncertainty in the water-use estimates. The conceptual model presented in this report is designed to be robust to characterize and simulate the data processing to estimate water use associated with UOG development. Although the results of an analysis that includes missing data have greater uncertainty, the analysis still can be insightful because it can establish a baseline estimate of UOG water use that may be refined further as more data become available. Analysis of models that include missing data also could aid in identifying the data most needed for future water-use estimates. Characterizing individual model limitations is important because the conceptual model can be used in future water-use studies to facilitate data compiling, data processing, estimating, and assessing UOG activities regardless of location.

Scientific Investigations Report↗

USGS2018

Assessment of potential risks from renewable energy development and other anthropogenic factors to wintering Golden Eagles in the western United States

Wind and other energy development are expanding rapidly and on an unprecedented scale within the range of the Golden Eagle ( Aquila chrysaetos ) while other anthropogenic-related changes, wildfires, invasive plants, drought, and climate change are altering or destroying native habitats occupied by Golden Eagles. However, the potential effects of these factors on North American Golden Eagle populations are largely unknown and the most recent evidence indicates that the population in the western United States is declining slightly. Impediments to evaluating the potential effects of energy development projects on wintering Golden Eagles include issues of scale and a paucity of available information about eagle winter use areas and ecology. We applied a predictive model of eagle winter distribution developed for Idaho and Montana, to Idaho, Utah, Nevada and eastern Oregon to help identify potential wintering areas and identify risks that occur in those areas. The model identifies ~40% of the four state study area as potentially suitable eagle winter habitat and provides a basis for spatial assessment of possible risk factors to eagles wintering there. We used eBird and Christmas Bird Count citizen science datasets for an independent evaluation of the accuracy of our predictive distribution model. The model was robust, accurately predicting the presence of wintering Golden Eagles significantly more often than expected. We used digital environmental datasets (layers) of potential risk factors, in conjunction with model predicted eagle distribution, to better understand and estimate the extent of risks to the wintering eagle population in the study area. These layers represent available data for some of the factors previously identified as risks in the landscape to wintering Golden Eagles. The majority of predicted eagle wintering areas occurred where there was little habitat fragmentation (<10%). All predicted winter areas contained at least one potential risk factor (e.g., potential for energy development); 39.4% of predicted winter areas contained at least two known risk factors. The greatest number of risks often occurred where the human footprint was highest and where eagles were less likely to occur during winter. Our results can be used to help prioritize field surveys for identifying important Golden Eagle winter areas in the western United States and determine potential locations where energy development is least likely to have negative effects on wintering eagles. Survey efforts can be allocated in consideration of management and conservation objectives based on predicted habitat suitability and risk factors. For example, surveys for areas of high suitability and low risk can identify places to focus management for conservation of eagle winter areas. Further, sites proposed for wind energy development could be reviewed initially based on model predicted eagle wintering areas and then surveyed to determine if permitting for development is appropriate.

Book chapter↗

USGS2017

Controls of multi-modal wave conditions in a complex coastal setting

Coastal hazards emerge from the combined effect of wave conditions and sea level anomalies associated with storms or low-frequency atmosphere-ocean oscillations. Rigorous characterization of wave climate is limited by the availability of spectral wave observations, the computational cost of dynamical simulations, and the ability to link wave-generating atmospheric patterns with coastal conditions. We present a hybrid statistical-dynamical approach to simulating nearshore wave climate in complex coastal settings, demonstrated in the Southern California Bight, where waves arriving from distant, disparate locations are refracted over complex bathymetry and shadowed by offshore islands. Contributions of wave families and large-scale atmospheric drivers to nearshore wave energy flux are analyzed. Results highlight the variability of influences controlling wave conditions along neighboring coastlines. The universal method demonstrated here can be applied to complex coastal settings worldwide, facilitating analysis of the effects of climate change on nearshore wave climate.

California↗

USGS2014

Assessing inundation hazards to nuclear powerplant sites using geologically extended histories of riverine floods, tsunamis, and storm surges

Most nuclear powerplants in the United States are near rivers, large lakes, or oceans. As evident from the Fukushima Daiichi, Japan, disaster of 2011, these water bodies pose inundation threats. Geologic records can extend knowledge of rare hazards from flooding, storm surges, and tsunamis. This knowledge can aid in assessing the safety of critical structures such as dams and energy plants, for which even remotely possible hazards are pertinent. Quantitative analysis of inundation from geologic records perhaps is most developed for and applied to riverine flood hazards, but because of recent natural disasters, geologic investigations also are now used widely for understanding tsunami hazards and coastal storm surges. Layered sedimentary deposits commonly give the most complete geologic record of large floods, storm surges, and tsunamis. Sedimentary layers may be preserved for hundreds or thousands of years in suitable depositional environments, thereby providing an archive of rare, high-magnitude events. All inundation hazards discussed in this report—riverine floods, tsunamis, and storm surges—have had long records extracted from sedimentary sequences, many specifically for hazard assessment. Geologic records commonly are imprecise, so most hazard assessments benefit from evaluation of many sites and rigorous uncertainty assessment. Despite uncertainties, geologic records commonly can improve knowledge of the types and magnitudes of hazards threatening specific sites or regions. New statistical tools and approaches can efficiently incorporate geologic information into frequency assessments. These tools are most developed for riverine flood hazards, but are to some degree transferable to other episodic natural phenomena such as tsunamis and storm surges. Even with these efficient statistical approaches for examining geologic records, systematic landscape changes may reduce the applicability of retrospective assessments. These non-stationarity issues (such as climate change, sea‑level rise, land-use, dams and flow regulation) may all affect the validity of using past experience—no matter how complete the record—to assess future likelihoods. These issues require site-specific consideration for nearly all hazard assessments drawn from geologic evidence. A screening of the 104 nuclear powerplants in the United States licensed by the Nuclear Regulatory Commission (at 64 sites) indicates several sites for which paleoflood studies likely would provide additional flood-frequency information. Two sites—Duane Arnold, Iowa, on the Cedar River; and David-Besse, Ohio, on the Toussaint River—have geologic conditions suitable for creating and preserving stratigraphic records of flooding and few upstream dams that may complicate flood-frequency analysis. One site—Crystal River, Florida1, on the Withlacoochee River and only 4 kilometers from the coast—has high potential as a candidate for assessing riverine and marine inundation hazards. Several sites on the Mississippi River have high geologic potential, but upstream dams almost certainly now regulate peak flows. Nevertheless, studies on the Mississippi River to evaluate long-term flood frequency may provide results applicable to a wide spectrum of regional hazard issues. Several sites in the southeastern United States have high geologic potential, and studies at these sites also may be helpful in evaluating hazards from outburst floods from landslide dams (river blockages formed by mass movements), which may be a regional hazard. For all these sites, closer investigation and field reconnaissance would be needed to confirm suitable deposits and settings for a complete paleoflood analysis. Similar screenings may help identify high-potential sites for geologic investigations of tsunami and storm-surge hazards.

Scientific Investigations Report↗

USGS2013

Actual evapotranspiration modeling using the operational Simplified Surface Energy Balance (SSEBop) approach

Remote-sensing technology and surface-energy-balance methods can provide accurate and repeatable estimates of actual evapotranspiration ( ETa ) when used in combination with local weather datasets over irrigated lands. Estimates of ETa may be used to provide a consistent, accurate, and efficient approach for estimating regional water withdrawals for irrigation and associated consumptive use (CU), especially in arid cropland areas that require supplemental water due to insufficient natural supplies from rainfall, soil moisture, or groundwater. ETa in these areas is considered equivalent to CU, and represents the part of applied irrigation water that is evaporated and/or transpired, and is not available for immediate reuse. A recent U.S. Geological Survey study demonstrated the application of the remote-sensing-based Simplified Surface Energy Balance (SSEB) model to estimate 10-year average ETa at 1-kilometer resolution on national and regional scales, and compared those ETa values to the U.S. Geological Survey’s National Water-Use Information Program’s 1995 county estimates of CU. The operational version of the operational SSEB (SSEBop) method is now used to construct monthly, county-level ETa maps of the conterminous United States for the years 2000, 2005, and 2010. The performance of the SSEBop was evaluated using eddy covariance flux tower datasets compiled from 2005 datasets, and the results showed a strong linear relationship in different land cover types across diverse ecosystems in the conterminous United States (correlation coefficient [r] ranging from 0.75 to 0.95). For example, r for woody savannas (0.75), grassland (0.75), forest (0.82), cropland (0.84), shrub land (0.89), and urban (0.95). A comparison of the remote-sensing SSEBop method for estimating ETa and the Hamon temperature method for estimating potential ET ( ETp ) also was conducted, using regressions of all available county averages of ETa for 2005 and 2010, and yielded correlations of r = 0.60 and r = 0.71, respectively. Correlations generally are stronger in the Southeast where ETa is close to ETp . SSEBop ETa provides more spatial detail and accuracy in the Southwest where irrigation is practiced in a smaller proportion of the region.

Scientific Investigations Report↗

USGS2019

A Methodology to Assess the National and Regional Impacts of U.S. Wind Energy Development on Birds and Bats

This scientific investigations report describes an effort by the U.S. Geological Survey (USGS) that used research, monitoring data, and modeling to develop a methodology to assess both the current and future population-level consequences of wind energy development on species of birds and bats that are present in the United States during any part of their life cycle. The methodology is currently applicable to birds and bats, focuses primarily on the effects of collisions with turbines, and can be applied to any species that breeds in, migrates through, or otherwise uses any part of the United States. The methodology assesses species at the national and regional scales and identifies those species potentially in need of more detailed study, as well as those species that are likely at low risk from wind energy development. This approach is fundamentally different from existing methods focusing on impacts at individual facilities. This report supersedes USGS Scientific Investigations Report 2015–5066 by the same authors, which described a preliminary version of the methodology. Following reviews of the preliminary methodology by a panel of external experts, public comments, and additional internal review, the methodology was revised and finalized. The three components of the refined methodology described in this new report rely on publicly available fatality information, population estimates, species range maps, turbine location data, biological characteristics of species, and population models. First, three metrics are combined to determine direct and indirect relative effects from wind energy facilities to generate a list of species scores. Second, a generic population model estimates the expected change in population trend caused by the additive mortality from collisions with wind turbines. Third, the methodology combines an estimate of observed fatalities and an estimate of potential biological removal to assess the possibility of a decrease in population size. The latter two components are quantitative. In a test case, the methodology was used to analyze data for six bird species and three bat species. Components of the methodology are based on simplifying assumptions and require information that, for many species, may be sparse or unreliable or may require further study. These assumptions should be carefully considered when using outputs from the methodology. Increases in the quality of data for fatalities from collisions with wind turbines, species distributions, abundance, and demography will likely improve results for uses of the methodology. The methodology’s design identifies and prioritizes a subset of the bird and bat species that may experience population-level impacts from collisions with wind turbines, both currently and from future wind energy development in the United States. Results of an assessment using this methodology could focus future research to improve our understanding of those impacts and to guide avoidance and minimization strategies. In addition, this methodology can be used to identify species for more intensive demographic modeling or to highlight those species that may not require any additional research because effects of wind energy development on their populations are projected to be small. The effects of wind energy facilities on nine unidentified species used in the test case described in this report have not been assessed. Their data were simply used to show the application of the methodology to real-world data and the types of outputs it would produce.

Scientific Investigations Report↗

USGS2009

Lysimetric evaluation of simplified surface energy balance approach in the Texas high plains

Numerous energy balance (EB) algorithms have been developed to make use of remote sensing data to estimate evapotranspiration (ET) regionally. However, most EB models are complex to use and efforts are being made to simplify procedures mainly through the scaling of reference ET. The Simplified Surface Energy Balance (SSEB) is one such method. This approach has never been evaluated using measured ET data. In this study, the SSEB approach was applied to 14 Landsat TM images covering a major portion of the Southern High Plains that were acquired during 2006 and 2007 cropping seasons. Performance of the SSEB was evaluated by comparing estimated ET with measured daily ET from four large monolithic lysimeters at the USDA-ARS Conservation and Production Research Laboratory, Bushland, Texas. Statistical evaluation of results indicated that the SSEB accounted for 84% of the variability in the measured ET values with a slope and intercept of 0.75 and 1.1 mm d -1 , respectively. Considering the minimal amount of ancillary data required and excellent performance in predicting daily ET, the SSEB approach is a promising tool for mapping ET in the semiarid Texas High Plains and in other parts of the world with similar hydro-climatic conditions.

Applied Engineering in Agriculture↗

USGS2009

Lysimetric Evaluation of Simplified Surface Energy Balance Approach in the Texas High Plains

Numerous energy balance (EB) algorithms have been developed to make use of remote sensing data to estimate evapotranspiration (ET) regionally. However, most EB models are complex to use and efforts are being made to simplify procedures mainly through the scaling of reference ET. The Simplified Surface Energy Balance (SSEB) is one such method. This approach has never been evaluated using measured ET data. In this study, the SSEB approach was applied to fourteen Landsat TM images covering a major portion of the Southern High Plains that were acquired during 2006 and 2007 cropping seasons. Performance of the SSEB was evaluated by comparing estimated ET with measured daily ET from four large monolithic lysimeters at the USDA-ARS Conservation and Production Research Laboratory, Bushland, Texas. Statistical evaluation of results indicated that the SSEB accounted for 84% of the variability in the measured ET values with a slope and intercept of 0.75 and 1.1 mm d-1, respectively. Considering the minimal amount of ancillary data required and excellent performance in predicting daily ET, the SSEB approach is a promising tool for mapping ET in the semiarid Texas High Plains and in other parts of the world with similar hydro-climatic conditions.

Applied Engineering in Agriculture↗