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Item Understanding the effects of floodplain shade on hyporheic and stream channel temperature cycles(Montana State University - Bozeman, College of Agriculture, 2024) Fogg, Sarah Kathleen; Chairperson, Graduate Committee: Geoffrey C. Poole; This is a manuscript style paper that includes co-authored chapters.River reaches with coarse-grained alluvial floodplains have a breadth of lateral interaction between the channel and surrounding landscape, yielding extensive riparian zones and high rates of gross water exchange between the channel and substrate (i.e., hyporheic exchange). The lateral hyporheic zone on floodplain rivers is often near the ground surface, allowing for heat exchange between the atmosphere, unsaturated sediments, and hyporheic zone. We hypothesized that floodplain shade overlying lateral hyporheic water influences the conductive heat flux through unsaturated sediments, thus influencing hyporheic temperatures and temperatures in associated stream channels. We conducted simulation modeling experiments to test the potential effects of floodplain shade on hyporheic and stream channel temperatures. We found that scenarios with floodplain shade led to cooler hyporheic and stream temperatures than scenarios lacking floodplain shade under a variety of realistic floodplain conditions. We conclude that floodplain forest shade is a novel consideration for riparian management on floodplain river reaches and may be crucial in managing and maintaining cold-water habitat into the future.Item The effect of permafrost thaw and geologic substrate on dissolved organic carbon mobilization and transformation in northern streams(Montana State University - Bozeman, College of Agriculture, 2019) Wologo, Ethan Andrew; Chairperson, Graduate Committee: Stephanie A. Ewing; Sarah Shakil, Scott Zolkos, Sadie Textor, Stephanie Ewing, Jane Klassen, Robert G.M. Spencer, David C. Podgorski, Suzanne E. Tank, Michelle A. Baker, Jonathan A. O'Donnell, Kimberly P. Wickland, Sydney S.W. Foks, Jay P. Zarnetske, Joseph Lee-Cullin, Futing Liu, Yuanhe Yang, Pirkko Kortelainen, Jaana Kolehmainen, Joshua F. Dean, Jorien E. Vonk, Robert M. Holmes, Gilles Pinay, Michaela M. Powell, Jansen Howe, Rebecca Frei and Benjamin W. Abbott were co-authors of the article, 'No evience of dissolved organic matter priming in permafrost stream networks: a circumpolar assessment' submitted to the journal 'Global biogeochemical cycles' which is contained within this thesis.; Stephanie Ewing, Jonathan A. O'Donnell, Jim Paces, Rob Striegl, Duane Froese and Joshua Koch were co-authors of the article, 'Groundwater connection and doc transport in the Yukon River Basin: uranium and strontium isotopes in permafrost catchments' submitted to the journal 'Global biogeochemical cycles' which is contained within this thesis.Permafrost landscapes exhibit unique hydrology that is linked both chemically and physically to nutrient cycling and geochemical processes. Permafrost thaw is expected to result in a positive feedback to Earth's climate system through carbon release to the atmosphere; this potential demands better understanding of hydrologic pathways in permafrost landscapes in the face of global change. The work that follows is divided into two main bodies of research that explore both carbon dynamics and isotope geochemistry of river waters draining permafrost catchments in the Yukon River Basin (YRB). The first study uses in-vitro incubations of stream water from seven permafrost regions to investigate how biolabile carbon additions (acetate) and inorganic nutrients (nitrogen and phosphorus) 'prime' water-column dissolved organic carbon (DOC) decomposition. No priming effect from biolabile carbon addition was evident through changes in DOC concentrations or compositional transformations, but consumption of added acetate was correlated with ambient nutrient concentrations. Sites with fine-textured, ice-rich substrate and proximal thermokarst features had higher ambient DOC and nutrient concentrations, and consequently the fastest rates of acetate consumption. We conclude that the fate of biolabile DOC released from degrading permafrost will depend largely on inorganic nutrient availability in receiving waterbodies. The second part of this thesis focuses on hydrology of intermediate-sized catchments in the YRB. We evaluate uranium isotope activity ratios ([234U/238U]) as tracers of groundwater-surface water connection in thawing permafrost landscapes. Streams draining loess-mantled areas had [234U/238U] values moderately increased relative to meteoric values. Streams draining low-order catchments with rocky substrate and surface disturbance exhibit dramatically increased [234U/238U] values, consistent with groundwater connection. In addition, we observed higher DOC concentrations both in areas influenced by recent thaw and where flow is restricted by ice-rich silt. The transformation of northern stream chemistry will likely continue as northern permafrost environents warm, with greatest resilience of ground ice in loess-blanketed areas not subject to thermal erosion by groundwater. As subsurface storage expands and groundwater exchange intensifies, ecosystems within and connected to northern streams will also be transformed, with implications for resource managers concerned with fish and wildlife management in these systems.Item The response of parafluvial soils to beaver mimicry restoration in a Montane stream(Montana State University - Bozeman, College of Agriculture, 2020) Whitehead, Briana Katherine; Chairperson, Graduate Committee: Tracy M. Sterling and William Kleindl (co-chair); Paul Stoy, William Kleindl, Martin Rabenhorst, Rob Payn, David Wood and Anthony Hartshorn were co-authors of the article, 'Parafluvial soil response to beaver mimicry restoration in a montane stream' submitted to the journal 'Restoration ecology' which is contained within this thesis.Beaver Mimicry Restoration (BMR) is a relatively new aquatic restoration practice that seeks to improve deteriorated stream ecological functions. BMR is designed to rejoin hydrologically disconnected streams with their adjacent floodplains via the installation of small-scale, stream-spanning structures derived from natural materials and inspired by the influence of natural beaver (Castor spp.) dams. These structures capture sediment, elevate stream stage and groundwater tables, create thermal refugia, and re-establish riparian vegetation. Most research on BMR has focused on the hydrological or botanical results, but little is known about the response of parafluvial soils. I report measurements of soil water content, soil temperature, soil biogeochemical reduction, and vegetation responses at paired BMR-influenced treatment and non-BMR-influenced control locations from June through September of 2018 and 2019 in a montane stream in southwestern Montana (USA). In comparison to soils at control sites, soils adjacent to BMR activity experienced an extended period of higher water contents (0.23 m 3/m 3 higher), increased anoxic conditions (on average 27% more during the field season), a less variable and cooler soil temperature range (on average 5 °C cooler), and supported longer durations of vegetation greenness (additional 20 days) during the dry months. Results demonstrate how BMR produces conducive conditions for the development of new and/or the reestablish of historic hydric soils.Item SR and U isotopes reveal interactions of surface water and groundwater along the mountain headwaters to intermountain basin transition (Hyalite Canyon and Gallatin Valley, MT)(Montana State University - Bozeman, College of Agriculture, 2018) Miller, Florence Rita; Chairperson, Graduate Committee: Stephanie A. Ewing; Stephanie A. Ewing, Robert A. Payn, James B. Paces, Sam Leuthold and Stephan Custer were co-authors of the article, 'SR and U isotopes reveal the influence of lithologic structure on stream-groundwater interaction along a mountain headwater catchment (Hyalite Canyon, MT)' submitted to the journal 'Water resources research' which is contained within this thesis.; Stephanie A. Ewing, Robert Payn, Sam Leuthold, Stephan Custer, Tom Michalek and James B. Paces were co-authors of the article, 'SR and U isotopes reveal mixing patterns of groundwater and surface water influenced by human management in an intermountain basin (Gallatin Valley, MT)' submitted to the journal 'Journal of hydrology' which is contained within this thesis.Mountainous regions of the western United States are characterized by steep, rapidly eroding mountain headwater streams transitioning to more depositional intermountain basins. The character and flux of water across these process domains is subject to projected changes in mountain headwater snowpack and agricultural and urban land use in rapidly developing intermountain basins. Here we evaluate controls on water/rock, water/substrate, and surface/groundwater interactions within Hyalite Creek and the Gallatin Valley of southwest Montana. We use solute loads and geochemical tracers (87 Sr/86 Sr, Ca/Sr, and [234U/238U]) as indicators of such interactions. Surface water, groundwater, and soil samples were collected between 2016 and 2018. Stream water in upper Hyalite Creek had low 87 Sr/86 Sr values typical of volcanic and sedimentary host rock units, and low [234 U/238 U] values consistent with shorter flow path soil, shallow aquifer or runoff water. Middle Hyalite Creek had increased [234 U/238 U] values, reflecting groundwater inflows from the Madison Group limestones. Lower Hyalite Creek had an increase in 87 Sr/86 Sr values and decrease in [234 U/238 U] values, indicated contributions from Archean gneiss fracture flow. Using mixing models, we estimate inflows from the Madison contribute ~4% during summer baseflow conditions and inflows from the Archean contribute ~2% to ~8% of streamflow during summer and winter baseflow conditions. At the mountain front, diverse Ca/Sr, 87Sr/86Sr, and [234U/238U] ratios were observed as a result of convergent flow in mountain headwaters catchments. In the intermountain basin, divergent flow at the mountain front recharges valley aquifers and combines with infiltration through soils. With distance down-valley, we observe intermediate values of Ca/Sr, 87 Sr/86 Sr, and [234 U/238 U], suggesting mixing of diverse source waters. Higher concentrations of Sr, alkalinity, and Ca/Sr and 87 Sr/86 Sr ratios consistent with soil carbonates suggest water infiltration through soil facilitated the influence of soil secondary carbonates on groundwater geochemistry. Additionally, increased water movement through soil facilitates the increase in anthropogenic loading of NO3- and Cl- in surface and groundwaters. Our results provide novel quantification of groundwater contribution to streamflow in mountain headwaters, and elucidate water quality and quantity controls from the mountain front across the intermountain basin, including valley aquifer recharge, infiltration through soils, and anthropogenic solute influxes to groundwater.Item Thermal insulation versus capacitance: a comparison of shading and hyporheic exchange on daily and annual stream temperature patterns(Montana State University - Bozeman, College of Agriculture, 2017) Fogg, Sarah Kathleen; Chairperson, Graduate Committee: Geoffrey Poole; Geoffrey C. Poole, AnnMarie Reinhold and Scott J. O'Daniel were co-authors of the article, 'Thermal insulation versus capacitance: a comparison of shade and hyporheic exchange on daily and annual stream temperature cycles' submitted to the journal 'Water resources research' which is contained within this thesis.Channel shading and hyporheic exchange both effect daily and annual stream temperature cycles. In streams with thermal regimes that are too warm to support native biota, increasing shading or hyporheic exchange have largely been thought of as interchangeable management strategies because they influence summertime stream channel temperatures in similar ways. But, shading and hyporheic exchange operate via different mechanisms and influence stream temperature differently at differently times of the year. To understand daily and seasonal differences of shading and hyporheic exchange on stream channel temperature we used a process-based heat-budget model of channel temperature. Our model incorporates stream channel-atmospheric energy exchanges and a novel channel-subsurface heat exchange model that more appropriately represents the effects of hyporheic residence time distributions. We used our model to conduct an in silico experiment where we vary shading and hyporheic exchange on the same stream reach. In summer, the cooling and damping of channel temperatures associated with an expansive, coarse-grained hyporheic zone were similar to shading effects. However, the differences between shading and hyporheic exchange effects were most pronounced in the winter when channel warming associated with hyporheic exchange was substantially greater than warming associated with shade. By interpreting the changes in heat fluxes between shading a stream and adding hyporheic exchange, we find that shading acts as a thermal insulator and hyporheic exchange acts as a thermal capacitor. Our results show that shading and hyporheic exchange can have similar and differently effects on stream channel temperatures depending on what part of the year the effects are investigated, which has important management and modeling implications. Geography and geomorphic context of a stream are important considerations when choosing shading or hyporheic exchange for thermal restoration. In bedrock-confined streams that historically had closed canopies, shading has the greatest potential to reduce summer temperatures while restoration of hyporheic restoration is impractical in these systems. In contrast, in large, coarse-grained alluvial stream reaches, where riparian vegetation is historically sparse, restoring hyporheic influences has the greatest potential for reducing summer temperatures while increasing streamside shading is likely unattainable.Item Response and resilience of rivers to historical resource use in the Greater Yellowstone Ecosystem : a repeat photography analysis(Montana State University - Bozeman, College of Agriculture, 2014) Clark, Heidi Martin; Chairperson, Graduate Committee: Robert A. PaynRepeat photographs provide a glimpse of the past and thus tell a story of how man and nature have shaped the landscape. With the use of repeat photography based on on-the-ground oblique images, this study investigated how historical natural resource uses (e.g., logging, mining, ranching, and dam building) have affected headwater rivers of the Greater Yellowstone Ecosystem (GYE). These rivers included the Gallatin, Yellowstone, Wind, Gros Ventre, Snake, Madison, and Green Rivers along with several of their tributaries. Oblique photo pairs or series of photos were compared using three types of analyses: quantitative pixel comparisons, rank order statistics, and individual descriptions, in order to identify changes in riparian vegetation cover, sinuosity, bankfull, and flood plain area. Additionally, additional data from a stream reach of the upper Yellowstone River in Paradise Valley, Montana, allowed for aerial comparisons to quantify vegetation cover and sinuosity within photo frame wedges of corresponding oblique photos. The results of the comparisons revealed: (1) increased riparian vegetation where anthropogenic perturbations had ceased, indicating resilience and recovery; (2) decreased riparian vegetation and sinuosity where impacts intensified; and (3) little change in riparian vegetation where human natural resource use continued at a similar intensity. Application of this methodology to more photo points and other regions will provide a better understanding of the extent of previous threats and how river systems have responded or continue to counter ongoing anthropogenic impacts.Item Hydrologic response to channel reconfiguration on Silver Bow Creek : science to inform the restoration process(Montana State University - Bozeman, College of Agriculture, 2010) Kurt-Mason, Seth James; Chairperson, Graduate Committee: Brian L. McGlynn; Geoffrey Poole (co-chair)Hydrologic residence time in streams is rarely considered as a response variable for assessing restoration design strategies. However, residence time is a useful index of hydrologic controls on ecosystem processes that may facilitate or limit the achievement of project goals. Interactions between the physical structure of streambeds and the patterns of flow through the channel determine hydrologic residence time and largely control solute transport and exchange among the various physical and biological components of the stream ecosystem. The influence of reach-scale channel reconfiguration on these complex interactions are not well characterized despite well-documented linkages between individual channel features, hydrologic retention, water quality, and in-stream habitat quality. This study documented changes in solute transport and variation in channel water velocity prior to and immediately following large-scale channel realignment along Silver Bow Creek in southwestern Montana. Channel restoration increased water residence time in the channel by increasing sinuosity, decreasing channel slope, and introducing frequent slow-moving pools. However, channel realignment yielded a reduction in the fine-scale variation in streambed topography. Therefore, post-realignment channel water velocities were more uniform, yielding a reduction in transient storage within the system, which could offset some of the beneficial effects of slower advective velocities. Restoration actions may be more effective at recovering normative hydrologic function if planning and design efforts consider the hydrologic effects and ecological benefits of fine-scale topographic variation and the bio-geomorphic processes that create and maintain such fine-scale variation over time.Item The role of stream network nutrient uptake kinetics and groundwater exchange in modifying the timing, magnitude, and form of watershed export(Montana State University - Bozeman, College of Agriculture, 2012) Covino, Timothy Patrick; Chairperson, Graduate Committee: Brian L. McGlynn.; Brian L. McGlynn and Rebecca A. McNamara were co-authors of the article, 'Tracer additions for spiraling curve characterization (TASCC): quantifying stream nutrient uptake kinetics from ambient to saturation' in the journal 'Limnology and oceanography: methods' which is contained within this thesis.; Brian McGlynn and Rebecca McNamara were co-authors of the article, 'Land use / land cover and scale influences on in-stream nitrogen uptake kinetics' in the journal 'Journal of geophysical research - biogeosciences' which is contained within this thesis.; Brian McGlynn and John Mallard were co-authors of the article, 'Stream-groundwater exchange and hydrologic turnover at the network scale' in the journal 'Water resources research' which is contained within this thesis.; Brian McGlynn and Michelle Baker were co-authors of the article, 'Separating physical and biological nutrient retention and quantifying uptake kinetics from ambient to saturation in successive mountain stream reaches' in the journal 'Journal of geophysical research - biogeosciences' which is contained within this thesis.In this PhD dissertation research we sought to elucidate stream network biological and physical influences on hydrological and biogeochemical signatures observed along stream networks and at watershed outlets. Our research indicates that stream nutrient uptake and groundwater exchange processes can modify inputs from terrestrial sources and influence the timing and signature of watershed fluxes. We determined that stream nutrient uptake followed Michaelis-Menten kinetics across a broad range of systems and that land use / land cover change can alter stream nutrient uptake magnitudes. Additionally, we found that watershed structure and network geometry exerted strong controls over sourcewater contributions and streamwater compositions along stream networks and at watershed outlets. Combined, this PhD research suggests that uptake kinetics and hydrologic turnover exert strong controls over streamwater composition and sourcewater contributions, and that physical and biological contributions to total nutrient retention and the dynamic and concentration dependent nature of biological uptake combine to control solute and nutrient signatures. We suggest accurate assessment of total retention across stream reaches and stream networks requires quantification of physical retention and the concentration dependent nature of biological uptake, understanding necessary to help mitigate the potentially deleterious influences elevated nutrient export can have on downstream ecosystems.Item Stream-groundwater interactions in a mountain to valley transition : impacts on watershed hydrologic response and stream water chemistry(Montana State University - Bozeman, College of Agriculture, 2005) Covino, Timothy Patrick; Chairperson, Graduate Committee: Brian L. McGlynn.As mountain headwater catchments increase in size to the meso-scale, they incorporate new landscape elements including mountain-valley transition zones. Mountain-valley transition zones form part of the mountain front, influence groundwater (GW)-stream interactions, and impact hydrologic response and stream water composition. Mountain front recharge (MFR) in mountain-valley transition zones and subsequent GW discharge to streams in the valley bottom are important hydrological processes. These GW-stream interactions are dynamic in both space and time, playing a key role in regulating the amount, timing, and chemistry of stream water reaching the valley bottom. I hypothesize that mountain-valley transitions function as hydrologic and biogeochemical buffers via GW recharge and subsequent GW discharge. More specifically, that streams often recharge GW near the mountain front and receive stored GW further downstream. To investigate these processes I applied physical hydrology techniques, and geochemical hydrograph separations in the Humphrey Creek watershed in southwestern Montana. This allowed me to assess the spatial and temporal variability of mountain front GW recharge and GW-stream interactions across a mountain-valley transition. Geochemical signatures were used to partition stream flow into alpine runoff and GW sources. These results indicate that much of the alpine stream water recharged GW at the mountain front and that stored GW of a different chemical composition sustained down-valley stream discharge. Down-valley stream discharge was dominated by GW inputs and responded to GW stage more closely than upstream reaches. A critical GW stage height was necessary for down-valley channel flow, as this was the only major input to channel flow during early and late season base flow. Conversely, GW contributed little to stream flow in the upper reaches of the study area. GW-stream water exchange served as a flow and geochemical buffer, resulting in significant changes in stream chemistry from the alpine, to the MFR zone, to the valley bottom and muting fluctuations in channel flow, both at high and low flow. Implications are that mountain front GW recharge magnitudes can control valley aquifer storage state which combined with alpine runoff magnitude and valley bottom GW discharge controls stream water quantity and geochemical composition downstream.Item Subalpine Wetlands : characterization, environmental drivers, and response to human perturbation and restoration(Montana State University - Bozeman, College of Agriculture, 2009) Heikes-Knapton, Sunni Marie; Chairperson, Graduate Committee: Duncan T. Patten.The subalpine region throughout the western US is increasingly pressured by land use changes. Consequences of these changes often involve major alteration to the original function of the landscape, particularly concerning wetland and riparian areas. In southwest Montana, large developments have recently been created or expanded in the subalpine environment. Wetlands in these regions bear a particularly unique structure, and often are influenced by the effects of development. The alteration to structure can result in disturbance to the original hydrological, ecological, and biogeochemical functions of wetlands. Restoration efforts attempt to mitigate for development influences, but the monitoring and success criteria do not wholly address the functional attributes of these features. At the same time, little is known about the structure of undisturbed subalpine wetlands and how environmental drivers influence the undisturbed structure and hydrological, ecological, and biogeochemical functions. Knowledge of these natural processes is necessary to ensure appropriate management decisions and future restoration success. This study examines small subalpine wetlands in an elevation range of 2256-2316 m located in southwest Montana. Study sites include two wetland types, in undisturbed and restored conditions. This research examines physical, chemical, biological, and hydrological attributes of wetlands in varying conditions, to define and compare wetland characteristics, determine primary environmental drivers of wetland ecological and biogeochemical functions, and compare response to human perturbation. Comparisons of our data indicate significant differences in all categories of parameters, and include metrics of biodiversity, primary productivity, hydrologic regime, and physical and chemical properties of the soil. Several environmental drivers are identified, with the primary driver of vegetation and redox response variables being depth to water and persistence of saturated conditions. The depressional wetland type is characterized by a distinct hydrologic regime, with these conditions being significantly related to a greater number of ecological and biogeochemical functions than the linear wetland type. Restoration data indicate that the restoration methods employed are sufficient in establishing the primary wetland characteristics used in wetland definition. However, the trajectory of restored wetlands indicates that long term recovery may result in wetlands exhibiting different structural and functional attributes than intended.