Inferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals

Abstract. In mountain headwater streams the quality and resilience of cold-water habitat is regulated by surface stream channel connectivity and groundwater exchange. These critical hydrologic processes are thought to be influenced by the stream corridor bedrock contact depth (sediment thickness), which is often inferred from sparse hillslope borehole information, piezometer refusal, and remotely sensed data. To investigate how local bedrock depth might control summer stream temperature and channel disconnection (dewatering) patterns, we measured stream corridor bedrock depth by collecting and interpreting 191 passive seismic datasets along eight headwater streams in Shenandoah National Park (Virginia USA). In addition, we used multiyear stream temperature and streamflow records to calculate summer baseflow metrics along and among the study streams. Finally, comprehensive visual surveys of stream channel dewatering were conducted in 2016, 2019, and 2021 during summer baseflow conditions (124 total km of stream length). We found that measured bedrock depths were not well-characterized by soils maps or an existing global-scale geologic dataset, where the latter overpredicted measured depths by 12.2 m (mean), or approximately four times the average bedrock depth of 2.9 m. Half of the eight study stream corridors had an average bedrock depth of less than 2 m. Of the eight study streams, Staunton River had the deepest average bedrock depth (3.4 m), the coldest summer temperature profiles, and substantially higher summer baseflow indices compared to the other study steams. Staunton River also exhibited paired air and water annual temperature signals suggesting deeper groundwater influence, and the stream channel did not dewater in lower sections during any baseflow survey. In contrast, streams Paine Run and Piney River did show pronounced, patchy channel dewatering, with Paine Run having dozens of discrete dry channel sections ranging 1 to greater than 300 m in length. Stream dewatering patterns were apparently influenced by a combination of discrete deep bedrock (20 m+) features and more subtle sediment thickness variation (1–4 m), depending on local stream valley hydrogeology. In combination these unique datasets show the first large-scale empirical support for existing conceptual models of headwater stream disconnection based on underflow capacity and shallow groundwater supply.

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Quantifying thermal refugia connectivity by combining temperature modeling, distributed temperature sensing, and thermal infrared imaging

Hydrology and Earth System Sciences ◽

10.5194/hess-23-2965-2019 ◽

2019 ◽

Vol 23 (7) ◽

pp. 2965-2982 ◽

Cited By ~ 11

Author(s):

Jessica R. Dzara ◽

Bethany T. Neilson ◽

Sarah E. Null

Keyword(s):

Cold Water ◽

Cutthroat Trout ◽

Stream Temperature ◽

Temperature Variability ◽

Main Stem ◽

Small Scale ◽

Thermal Refugia ◽

Lahontan Cutthroat Trout ◽

Temperature Ranges ◽

Walker River

Abstract. Watershed-scale stream temperature models are often one-dimensional because they require fewer data and are more computationally efficient than two- or three-dimensional models. However, one-dimensional models assume completely mixed reaches and ignore small-scale spatial temperature variability, which may create temperature barriers or refugia for cold-water aquatic species. Fine spatial- and temporal-resolution stream temperature monitoring provides information to identify river features with increased thermal variability. We used distributed temperature sensing (DTS) to observe small-scale stream temperature variability, measured as a temperature range through space and time, within two 400 m reaches in summer 2015 in Nevada's East Walker and main stem Walker rivers. Thermal infrared (TIR) aerial imagery collected in summer 2012 quantified the spatial temperature variability throughout the Walker Basin. We coupled both types of high-resolution measured data with simulated stream temperatures to corroborate model results and estimate the spatial distribution of thermal refugia for Lahontan cutthroat trout and other cold-water species. Temperature model estimates were within the DTS-measured temperature ranges 21 % and 70 % of the time for the East Walker River and main stem Walker River, respectively, and within TIR-measured temperatures 17 %, 5 %, and 5 % of the time for the East Walker, West Walker, and main stem Walker rivers, respectively. DTS, TIR, and modeled stream temperatures in the main stem Walker River nearly always exceeded the 21 ∘C optimal temperature threshold for adult trout, usually exceeded the 24 ∘C stress threshold, and could exceed the 28 ∘C lethal threshold for Lahontan cutthroat trout. Measured stream temperature ranges bracketed ambient river temperatures by −10.1 to +2.3 ∘C in agricultural return flows, −1.2 to +4 ∘C at diversions, −5.1 to +2 ∘C in beaver dams, and −4.2 to 0 ∘C at seeps. To better understand the role of these river features on thermal refugia during warm time periods, the respective temperature ranges were added to simulated stream temperatures at each of the identified river features. Based on this analysis, the average distance between thermal refugia in this system was 2.8 km. While simulated stream temperatures are often too warm to support Lahontan cutthroat trout and other cold-water species, thermal refugia may exist to improve habitat connectivity and facilitate trout movement between spawning and summer habitats. Overall, high-resolution DTS and TIR measurements quantify temperature ranges of refugia and augment process-based modeling.

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Trend of stream temperature and its drivers over the past 55 years in a large European River basin

10.5194/egusphere-egu21-9529 ◽

2021 ◽

Author(s):

Hanieh Seyedhashemi ◽

Florentina Moatar ◽

Jean-Philippe Vidal ◽

Dominique Thiery ◽

Céline Monteil ◽

...

Keyword(s):

River Basin ◽

Air Temperature ◽

Cold Water ◽

Stream Temperature ◽

Small Rivers ◽

The South ◽

Massif Central ◽

The Past ◽

Temperature Trends

Air temperature has been increasing all around the world over the past decades. Owing to its sensitivity to air temperature, it is consequently expected that stream temperature experiences an increase as well. However, due to paucity of long-term stream temperature data, assessments of the magnitude of such trends in relation with landscape and hydrological changes have remained scarce.The present study used a physically-based thermal model (T-NET: Temperature-NETwork), coupled with a semi-distributed hydrological model (EROS) to reconstruct past daily stream temperatures and discharges at the scale of the Loire River basin in France (105 km2 with 52278 reaches). The ability of both models to reconstruct long-term trends was assessed at 44 gauging stations and 11 stream temperature stations. &#160;T-NET simulations over the 1963-2017 period show that there has been a significant increasing trend in stream temperatures for at least 70% of reaches in all seasons (median=0.36 &#176;C/decade). Significantly increasing trends are more prominent in spring (Mar-May) and summer (Jun-Aug) with a median increase of 0.37 &#176;C (0.11 to 0.8&#176;C) and 0.42&#176;C (0.14 to 1 &#176;C) per decade, respectively. For 81 % of reaches, annual stream temperature trends are greater than annual air temperature trends (median ratio=1.21; interquartile ranges: 1.06-1.44). Greater increases in stream temperature in spring and summer are found in the south of the basin, mostly in the Massif Central (up to 1&#176;C/decade) where greater increase in air temperature (up to 0.67 &#176;C/decade) and greater decrease in discharge (up to -16%/decade) occur jointly. The increase of stream temperature is also higher in large rivers compared to small rivers where riparian vegetation shading mitigate the increase in temperature. For the majority of reaches, changes in stream temperature, air temperature, and discharge significantly intensified in the late 1980s.These climate-induced changes in the annual and seasonal stream temperature could help us to explain shifts in the phenology and geographical distribution of cold-water fish especially in the south of the basin where trends are more pronounced.

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Potential for Managed Aquifer Recharge to Enhance Fish Habitat in a Regulated River

Water ◽

10.3390/w12030673 ◽

2020 ◽

Vol 12 (3) ◽

pp. 673 ◽

Cited By ~ 4

Author(s):

Robert W. Van Kirk ◽

Bryce A. Contor ◽

Christina N. Morrisett ◽

Sarah E. Null ◽

Ashly S. Loibman

Keyword(s):

Water Temperature ◽

Brown Trout ◽

Cold Water ◽

Stream Temperature ◽

Managed Aquifer Recharge ◽

Regulated River ◽

Snake River ◽

Irrigated Agriculture ◽

Aquifer Recharge ◽

Fisheries Conservation

Managed aquifer recharge (MAR) is typically used to enhance the agricultural water supply but may also be promising to maintain summer streamflows and temperatures for cold-water fish. An existing aquifer model, water temperature data, and analysis of water administration were used to assess potential benefits of MAR to cold-water fisheries in Idaho’s Snake River. This highly-regulated river supports irrigated agriculture worth US $10 billion and recreational trout fisheries worth $100 million. The assessment focused on the Henry’s Fork Snake River, which receives groundwater from recharge incidental to irrigation and from MAR operations 8 km from the river, addressing (1) the quantity and timing of MAR-produced streamflow response, (2) the mechanism through which MAR increases streamflow, (3) whether groundwater inputs decrease the local stream temperature, and (4) the legal and administrative hurdles to using MAR for cold-water fisheries conservation in Idaho. The model estimated a long-term 4%–7% increase in summertime streamflow from annual MAR similar to that conducted in 2019. Water temperature observations confirmed that recharge increased streamflow via aquifer discharge rather than reduction in river losses to the aquifer. In addition, groundwater seeps created summer thermal refugia. Measured summer stream temperature at seeps was within the optimal temperature range for brown trout, averaging 14.4 °C, whereas ambient stream temperature exceeded 19 °C, the stress threshold for brown trout. Implementing MAR for fisheries conservation is challenged by administrative water rules and regulations. Well-developed and trusted water rights and water-transaction systems in Idaho and other western states enable MAR. However, in Idaho, conservation groups are unable to engage directly in water transactions, hampering MAR for fisheries protection.

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Classifying California’s stream thermal regimes for cold-water conservation

PLoS ONE ◽

10.1371/journal.pone.0256286 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0256286

Author(s):

Ann D. Willis ◽

Ryan A. Peek ◽

Andrew L. Rypel

Keyword(s):

Thermal Regime ◽

Water Conservation ◽

Native Species ◽

Cold Water ◽

Pacific Salmon ◽

Stream Temperature ◽

Flow Regulation ◽

Anthropogenic Factors ◽

Thermal Regimes ◽

Water Ecosystems

Stream temperature science and management is rapidly shifting from single-metric driven approaches to multi-metric, thermal regime characterizations of streamscapes. Given considerable investments in recovery of cold-water fisheries (e.g., Pacific salmon and other declining native species), understanding where cold water is likely to persist, and how cold-water thermal regimes vary, is critical for conservation. California’s unique position at the southern end of cold-water ecosystems in the northern hemisphere, variable geography and hydrology, and extensive flow regulation requires a systematic approach to thermal regime classification. We used publicly available, long-term (> 8 years) stream temperature data from 77 sites across California to model their thermal regimes, calculate three temperature metrics, and use the metrics to classify each regime with an agglomerative nesting algorithm. Then, we assessed the variation in each class and considered underlying physical or anthropogenic factors that could explain differences between classes. Finally, we considered how different classes might fit existing criteria for cool- or cold-water thermal regimes, and how those differences complicate efforts to manage stream temperature through regulation. Our results demonstrate that cool- and cold-water thermal regimes vary spatially across California. Several salient findings emerge from this study. Groundwater-dominated streams are a ubiquitous, but as yet, poorly explored class of thermal regimes. Further, flow regulation below dams imposes serial discontinuities, including artificial thermal regimes on downstream ecosystems. Finally, and contrary to what is often assumed, California reservoirs do not contain sufficient cold-water storage to replicate desirable, reach-scale thermal regimes. While barriers to cold-water conservation are considerable and the trajectory of cold-water species towards extinction is dire, protecting reaches that demonstrate resilience to climate warming remains worthwhile.

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Waning habitats due to climate change: the effects of changes in streamflow and temperature at the rear edge of the distribution of a cold-water fish

Hydrology and Earth System Sciences ◽

10.5194/hess-21-4073-2017 ◽

2017 ◽

Vol 21 (8) ◽

pp. 4073-4101 ◽

Cited By ~ 12

Author(s):

José María Santiago ◽

Rafael Muñoz-Mas ◽

Joaquín Solana-Gutiérrez ◽

Diego García de Jalón ◽

Carlos Alonso ◽

...

Keyword(s):

Climate Change ◽

Brown Trout ◽

Cold Water ◽

Local Level ◽

Stream Temperature ◽

Risk Level ◽

Model Parameters ◽

Linear Regression Method ◽

Rear Edge ◽

Water Fish

Abstract. Climate changes affect aquatic ecosystems by altering temperatures and precipitation patterns, and the rear edges of the distributions of cold-water species are especially sensitive to these effects. The main goal of this study was to predict in detail how changes in air temperature and precipitation will affect streamflow, the thermal habitat of a cold-water fish (the brown trout, Salmo trutta), and the synergistic relationships among these variables at the rear edge of the natural distribution of brown trout. Thirty-one sites in 14 mountain rivers and streams were studied in central Spain. Models of streamflow were built for several of these sites using M5 model trees, and a non-linear regression method was used to estimate stream temperatures. Nine global climate models simulations for Representative Concentration Pathways RCP4.5 and RCP8.5 scenarios were downscaled to the local level. Significant reductions in streamflow were predicted to occur in all of the basins (max. −49 %) by the year 2099, and seasonal differences were noted between the basins. The stream temperature models showed relationships between the model parameters, geology and hydrologic responses. Temperature was sensitive to streamflow in one set of streams, and summer reductions in streamflow contributed to additional stream temperature increases (max. 3.6 °C), although the sites that are most dependent on deep aquifers will likely resist warming to a greater degree. The predicted increases in water temperatures were as high as 4.0 °C. Temperature and streamflow changes will cause a shift in the rear edge of the distribution of this species. However, geology will affect the extent of this shift. Approaches like the one used herein have proven to be useful in planning the prevention and mitigation of the negative effects of climate change by differentiating areas based on the risk level and viability of fish populations.

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Waning habitats due to climate change: effects of streamflow and temperature changes at the rear edge of the distribution of a cold-water fish

10.5194/hess-2016-606 ◽

2017 ◽

Cited By ~ 1

Author(s):

José M. Santiago ◽

Rafael Muñoz-Mas ◽

Joaquín Solana ◽

Diego García de Jalón ◽

Carlos Alonso ◽

...

Keyword(s):

Climate Change ◽

Cold Water ◽

Local Level ◽

Stream Temperature ◽

Global Climate Models ◽

Risk Level ◽

Linear Regression Method ◽

Rear Edge ◽

Temperature And Precipitation ◽

Water Fish

Abstract. Climate change affects aquatic ecosystems altering temperature and precipitation patterns, and the rear edge of the distribution of cold-water species is especially sensitive to them. The main goal was to predict in detail how change in air temperature and precipitation will affect streamflow, the thermal habitat of a cold-water fish (brown trout, Salmo trutta Linnaeus 1758), and their synergistic relationships at the rear edge of its natural distribution. 31 sites in 14 mountain rivers and streams were studied in Central Spain. Models at several sites were built using regression trees for streamflow, and a non-linear regression method for stream temperature. Nine global climate models simulations for the RCP4.5 and RCP8.5 (Representative Concentration Pathways) scenarios were downscaled to a local level. Significant streamflow reductions were predicted in all basins (max. −49 %) by the year 2099, showing seasonal differences between them. The stream temperature models showed relationships between models parameters, geology and hydrologic responses. Temperature was sensitive to the streamflow in one set of streams, and summer reductions contributed to additional stream temperature increases (max. 3.6 °C), although the most deep-aquifer dependent sites better resisted warming. The predicted increase in water temperature reached up to 4.0 °C. Temperature and streamflow changes will cause a shift of the rear edge of the species distribution. However, geology conditioned the extent of this shift. Approaches like these should be useful in planning the prevention and mitigation of negative effects of climate change by differentiating areas based on the risk level and viability of fish populations.

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Quantifying Small-scale Temperature Variability using Distributed Temperature Sensing and Thermal Infrared Imaging to Inform River Restoration

10.5194/hess-2018-441 ◽

2018 ◽

Author(s):

Jessica R. Dzara ◽

Bethany T. Neilson ◽

Sarah E. Null

Keyword(s):

Cold Water ◽

Thermal Infrared ◽

Stream Temperature ◽

Temperature Variability ◽

Temperature Sensing ◽

Small Scale ◽

Watershed Scale ◽

Distributed Temperature Sensing ◽

Thermal Refugia ◽

Thermal Variability

Abstract. Watershed-scale stream temperature models are often one-dimensional because they require less data and are more computationally efficient than two- or three-dimensional models. However, one-dimensional models assume completely mixed reaches and ignore small-scale spatial temperature variability, which may create temperature barriers or refugia for cold water aquatic species. Fine spatial- and temporal-resolution stream temperature monitoring provides information to identify river features with temperature ranges that differ from the reach average. We used a distributed temperature sensing system to observe small-scale stream temperature variability, measured as temperature range through space and time, within two 400 meter reaches in summer 2015 in Nevada's East Walker and mainstem Walker Rivers. In addition, thermal infrared aerial imagery collected in summer 2012 quantified the spatial variability of river temperatures throughout the Walker Basin. Both the distributed temperature sensing data and thermal infrared aerial imagery were used to corroborate prior temperature model results. Additionally, these data highlighted that beaver dams and irrigation return flow channels maximize thermal variability and can provide thermal refugia, while groundwater seeps provide small cooler areas and diversion canals often create warm local temperatures downstream. To extend temperature predictions and obtain a better understanding of thermal variability at the watershed-scale, temperatures bounds from observations by river features were added to the longitudinal temperature predictions. These results show that while bulk stream temperatures are often too warm to support trout and other cold-water species, thermal refugia may exist to improve habitat connectivity and passage for migratory species between Walker River and Lake. Overall, river restoration efforts should focus on maintaining and enhancing features that create this thermal variability and habitat connectivity.

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Forest riparian buffers reduce timber harvesting effects on stream temperature, but additional climate adaptation strategies are likely needed under future conditions

Journal of Water and Climate Change ◽

10.2166/wcc.2020.031 ◽

2020 ◽

Author(s):

Hillary N. Yonce ◽

Saumya Sarkar ◽

Jonathan B. Butcher ◽

Thomas E. Johnson ◽

Susan H. Julius ◽

...

Keyword(s):

Thermal Stress ◽

Water Temperature ◽

Cold Water ◽

Stream Water ◽

Timber Harvest ◽

Timber Harvesting ◽

Stream Temperature ◽

Riparian Buffers ◽

Adaptation Strategies ◽

Riparian Management

Abstract Stream water temperature imposes metabolic constraints on the health of cold-water fish like salmonids. Timber harvesting can reduce stream shading leading to higher water temperatures, while also altering stream hydrology. In the Pacific Northwest, riparian buffer requirements are designed to mitigate these impacts; however, anticipated future changes in air temperature and precipitation could reduce the efficacy of these practices in protecting aquatic ecosystems. Using a combined modeling approach (Soil and Water Assessment Tool (SWAT), Shade, and QUAL2K), this study examines the effectiveness of riparian buffers in reducing impacts of timber harvest on stream water temperature in Lookout Creek, Oregon across a range of potential future climates. Simulations assess changes in riparian management alone, climate alone, and combined effects. Results suggest that maximum stream water temperatures during thermal stress events are projected to increase by 3.3–7.4 °C due to hydroclimatic change alone by the end of this century. Riparian management is effective in reducing stream temperature increases from timber harvesting alone but cannot fully counteract the additional effects of a warming climate. Overall, our findings suggest that the protection of sensitive aquatic species will likely require additional adaptation strategies, such as the protection or provisioning of cool water refugia, to enhance survival during maximum thermal stress events.

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Effects of land use on summer thermal regimes in critical salmonid habitats of the Pacific Northwest

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2018-0165 ◽

2019 ◽

Vol 76 (5) ◽

pp. 753-761 ◽

Cited By ~ 3

Author(s):

Ryan P. Kovach ◽

Clint C. Muhlfeld ◽

Robert Al-Chokhachy ◽

Jeffrey V. Ojala ◽

Eric K. Archer

Keyword(s):

Climate Change ◽

Pacific Northwest ◽

Land Management ◽

Management Practices ◽

Cold Water ◽

Stream Temperature ◽

Livestock Grazing ◽

Temperature Regimes ◽

Thermal Regimes ◽

Conservation Concern

The effect of climate change on stream temperature regimes is of significant concern to natural resource managers focused on protecting cold-water-dependent species. Nevertheless, understanding of how human land-use activities may act to exacerbate the effects of climate change on stream temperature regimes is limited. Using extensive stream temperature data with high-resolution climate and habitat data, we quantified how land management activities are related to summer stream temperatures across the Pacific Northwest, USA. We then described the distribution of land management practices influencing summer thermal regimes relative to the distribution of salmonid fish species of conservation concern. After accounting for climatic and geophysical variation, we detected a strong relationship between livestock grazing and summer thermal regimes. Maximum, average, and diel variation in water temperature was greater where livestock grazing was present. Livestock grazing was widespread, occurring in 43%–100% of sites supporting salmonid species of conservation concern. Thus, current land management practices may be intensifying the effects of ongoing climate change in freshwater habitats, acting to further threaten cold-water fishes of conservation concern.

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