5/22/2016  |   10:30 - 10:45   |  315

WHEN AND HOW DYNAMIC HYPORHEIC TEMPERATURE MOSAICS INFLUENCE CHANNEL TEMPERATURE REGIMES Because hyporheic residence times follow a power-law distribution and residence time determines hyporheic temperature, the temperature pattern of hyporheic water returning to the channel is spatially variable and changes over time. Therefore, hyporheic exchange may alter diel and annual channel temperature cycles in complex ways. We developed a simple 2D stream temperature model that simulates heat exchange among the atmosphere, channel, and hyporheic zone. The model partitions the hyporheic zone by residence time, tracks the temperature of water returning to the channel from each partition, and thus simulates the resulting influence on mean stream channel temperature. We performed a sensitivity analysis by varying modeled hyporheic volume, magnitude of hyporheic exchange, stream width, and channel shading. Model results reveal patterns in diel and annual stream temperature cycles indicative of high rates of hyporheic exchange. We expect to use such patterns in the field to identify stream reaches with substantial hyporheic influence.

Katie Fogg (Primary Presenter/Author), Montana State University, s.katie.fogg@gmail.com;


Geoffrey Poole ( Co-Presenter/Co-Author), Montana State University, Montana Institute on Ecosystems, gpoole@montana.edu ;


Scott O'Daniel ( Co-Presenter/Co-Author), Confederated Umatilla Tribes, scottodaniel@ctuir.org;


Robert Payn ( Co-Presenter/Co-Author), Montana State University, Montana Institute on Ecosystems, rpayn@montana.edu;


Sam Carlson ( Co-Presenter/Co-Author), Montana State University, sam.p.carlson@gmail.com;


Amanda Hyman ( Co-Presenter/Co-Author), Virginia Tech, amanda.a.hyman@gmail.com;


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5/22/2016  |   10:45 - 11:00   |  315

SELECTIN ANNUAL TEMPERATURE SIGNALS FOR INVERSE MODELING OF AQUIFER HYDRAULIC PROPERTIES Annual temperature signals measured in hyporheic zones of coarse-grained alluvial aquifers exhibit amplitude damping (AD) and phase lagging (PL) with increasing residence time. We analyzed the covariation of AD and PL in all permutative pairs of sixteen monitoring wells in the expansive hyporheic zone of Meacham Creek, Oregon, USA. The slope of AD/PL ratios was <1 for short flow paths, in accordance with expected patterns from advection and conduction of heat. However, the slope of AD/PL ratios for long flow paths was >1, indicating the influence of external heat sources or sinks on hyporheic water temperature. We conclude that processes other than advection and conduction convolute temperature signals at longer residence times. Analysis of AD/PL ratios provides an objective criterion for selecting flow path lengths with minimal convolution, which therefore yield data appropriate for inverse modeling of aquifer properties.

Byron Amerson (Primary Presenter/Author), Montana State University, byron.amerson@gmail.com;


Geoffrey Poole ( Co-Presenter/Co-Author), Montana State University, Montana Institute on Ecosystems, gpoole@montana.edu ;


Scott O'Daniel ( Co-Presenter/Co-Author), Confederated Umatilla Tribes, scottodaniel@ctuir.org;


Michael Lambert ( Co-Presenter/Co-Author), Umatilla Tribes, MikeLambert@ctuir.org;


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5/22/2016  |   11:00 - 11:15   |  315

ABIOTIC AND BIOTIC HOMOGENIZATION BY DAMS IN STREAM ECOSYSTEMS Natural stream environment generally differ among regions due to metrological and geological characteristics, and in response to the variations, stream organisms should have distinctiveness (high beta diversity) at large spatial scales. However, dam construction has altered stream environment such as flow regime, which has been considered to be homogenized. Since stream invertebrates are influenced by flow variation, flow homogenization can decrease beta diversity (biotic homogenization). In addition, large amounts of sediment are trapped in reservoirs, causing subsequent coarse sediment below dams. Since variation in sediment is crucial for diversity in stream invertebrates, habitat homogenization may also promote biotic homogenization. Then, we assembled data of stream-flow, substrate material size, and stream invertebrates above and below dams, and examined whether dam construction drive flow and habitat homogenization and whether these abiotic homogenization link to biotic homogenization in stream invertebrates. In Japanese streams, flow alteration was minor and significant flow homogenization was not observed. Habitat homogenization was detected because substrate was coarser and size variation was smaller below than above the dam. Then, we will present relationships between abiotic and biotic homogenization.

Terutaka Mori (Primary Presenter/Author), University of Tokyo, moriterutaka@gmail.com;


Kei Uchida ( Co-Presenter/Co-Author), University of Tokyo, k.uchida023@gmail.com;


Yuichi Kayaba ( Co-Presenter/Co-Author), Public Works Research Institute, y-kayaba@pwri.go.jp;


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5/22/2016  |   11:15 - 11:30   |  315

RIVERBED FRACTAL TOPOGRAPHY AND HYPORHEIC RESIDENCE TIME DISTRIBUTIONS River topography is famously fractal, and the fractality of the sediment bed surface can produce scaling in solute residence time distributions. Empirical evidence showing the relationship between fractal bed topography and scaling of hyporheic travel times is still scarce. Here, I present results from numerical simulations that relate the scaling exponent of the bed topography to that of the residence time distribution in the bed under different flow conditions. I generated fractal landscapes and used physically based transport models to measure residence time distributions. I found that the fractal properties of the bed topography controlled solute residence time distributions. Overall, these results provide detailed evidence of the coupling between bed topography and anomalous transport scaling in flowing surface freshwater

Antoine Aubeneau (Primary Presenter/Author), Purdue University, aubeneau@gmail.com;


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5/22/2016  |   11:30 - 11:45   |  315

UPSCALING HYDROECOLOGICAL UNDERSTANDING OF GROUNDWATER-FED STREAM SYSTEMS ACROSS DENALI NATIONAL PARK (DNP), INTERIOR ALASKA The study aim was to better understand the hydroecological dynamics of groundwater-fed streams in glacierized watersheds at wider spatial scales. To this end physicochemistry and aquatic macroinvertebrate communities across five groundwater-fed stream systems were characterized within glacierized catchments of interior Alaska. Water hydrochemistry, channel stability, flow permanence, and macroinvertebrate community data were collected over two summer seasons (2014-2015). Flow permenance was an overriding control on macroinvertebrate community structure with distinct differences between ephemeral and perennial streams systems. Both perennial and ephemeral stream systems displayed variation in macroinvertebrate communities as a result in intra-site variations in hydrological dynamics. Across the groundwater-fed stream systems in general, shallow subsurface flows were highly important for maintaining streamflow and macroinvertebrate diversity. Canonical Correspondance Analysis (CCA) indicated potassium, nitrate and electrical conductivity were the major variables controlling macroinvertebrate community structure in these systems. The diversity of macroinvertebrate communities observed across paraglacial groundwater-fed stream systems indicates their importance as biodiversity hotspots in northern glacierized catchments which are potentially under threat by climate change.

Fredric Windsor (Primary Presenter/Author), Cardiff University, windsorfm@cardiff.ac.uk;


Michael Grocott ( Co-Presenter/Co-Author), University of Birmingham, MXG269@student.bham.ac.uk;


Victoria Milner ( Co-Presenter/Co-Author), University of Worcester, v.milner@worc.ac.uk;


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5/22/2016  |   11:45 - 12:00   |  315

WATER LEVEL CONTROLS ON SURFACE WATER HEATING AND STREAM-BED TEMPERATURE PATTERNS IN ARTIFICIAL RIVERS The potential drought impacts on the downstream heating of surface water and spatial patterns of streambed surface temperatures as a function of water level were investigated in three outdoor flumes using fiber optic distribute temperature sensing (FO-DTS). The flumes were designed with the same sequences of pool-riffle-pool bedforms, but had variable water levels and co-evolved vegetation densities. Results indicate that both spatial stream-bed temperature patterns as well as surface water heating differed significantly for different water levels. In particular, during high energy flux processes, temperatures in the flume with the lowest water depths and partially with isolated and exposed bedforms rose at more than twice the values than the deeper flumes. Similarly, streambed temperature patterns were more pronounced in the shallowest flume, with extreme temperature values and diel temperature variation being more affected by different weather conditions than the average values. Longitudinal temperature patterns matched bedform topography in all flumes, with riffles representing higher stream-bed and water temperature locations, and pools representing colder locations. Maintaining minimum water levels in lowland rivers during droughts is essential for buffering the thermal impacts.

Silvia Folegot (Primary Presenter/Author), University of Birmingham, School of Geography, Earth and Environmental Sciences, UK, SXF356@student.bham.ac.uk;


Joe Cullin ( Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan, USA , joe.a.cullin@gmail.com;


Jen Drummond ( Co-Presenter/Co-Author), Spanish National Research Council (CEAB-CSIC), j-drummond@u.northwestern.edu;


David Hannah ( Co-Presenter/Co-Author), University of Birmingham, UK, D.M.HANNAH@bham.ac.uk;


Toralf Keller ( Co-Presenter/Co-Author), Department of Hydrogeology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany, toralf.keller@ufz.de;


Megan Klaar ( Co-Presenter/Co-Author), School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, U.K. , M.J.Klaar@bham.ac.uk;


Marie J. Kurz ( Co-Presenter/Co-Author), Oak Ridge National Laboratory , kurzmj@ornl.gov;


Mark Ledger ( Co-Presenter/Co-Author), University of Birmingham, m.e.ledger@bham.ac.uk;


Eugènia Martí ( Co-Presenter/Co-Author), Integrated Freshwater Ecology Group, Center for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Girona, Spain, eugenia@ceab.csic.es;


Jay Zarnetske ( Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, jpz@msu.edu;


Stefan Krause ( Co-Presenter/Co-Author), School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, U.K. , S.Krause@bham.ac.uk;


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