Monday, May 23, 2016
10:30 - 12:00

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10:30 - 10:45: / 308 TEMPORAL VARIATION IN FLOW ALTERATION OF INTERMITTENT AND PERENNIAL STREAMS IN THE INTERIOR HIGHLANDS

5/23/2016  |   10:30 - 10:45   |  308

TEMPORAL VARIATION IN FLOW ALTERATION OF INTERMITTENT AND PERENNIAL STREAMS IN THE INTERIOR HIGHLANDS Hydrologic alteration is an important issue affecting stream ecosystems globally. Effects of flow alteration are likely to vary temporally and to be flow regime dependent. We examined flow alteration in seven natural flow regimes of the Interior Highlands, USA: Groundwater Stable, Groundwater, Groundwater Flashy, Perennial Runoff, Runoff Flashy, Intermittent Runoff and Intermittent Flashy. We estimated flow alteration (observed/expected) at 175 sites with U.S. Geological Survey stream gages for each of 171 hydrologic metrics in the categories of magnitude, frequency, duration, timing and rate of change. Temporal variation in flow alteration was examined and related to factors such as climate change. Flow alteration patterns in flow regimes will be compared with a focus on intermittent versus perennial streams. Preliminary results show that reductions in flow are more common than flow increases and significant reductions in flow are more common in intermittent than perennial streams. Altered hydrology is likely to affect ecosystem structure and function of intermittent streams and may influence the vital role these streams play in material transport and biological connectivity.

Daniel Magoulick (Primary Presenter/Author), Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas, danmag@uark.edu;


Doug Leasure ( Co-Presenter/Co-Author), University of Georgia, doug.leasure@gmail.com;


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10:45 - 11:00: / 308 CAN STREAM GAGE DATA PREDICT LARGE-SCALE DRYING PATTERNS IN INTERMITTENT RIVER NETWORKS? AN ANALYSIS USING LONG-TERM WET/DRY MAPPING DATA FROM 3 RIVERS

5/23/2016  |   10:45 - 11:00   |  308

CAN STREAM GAGE DATA PREDICT LARGE-SCALE DRYING PATTERNS IN INTERMITTENT RIVER NETWORKS? AN ANALYSIS USING LONG-TERM WET/DRY MAPPING DATA FROM 3 RIVERS Streamflow data is continuously collected at specific points in intermittent rivers all over the globe, but characterization of river drying patterns within a river network over large spatiotemporal scales remains a challenge. Here we investigate the potential for continuously collected discharge data collected at a single stream gage within an intermittent river to predict spatial drying patterns. We use long-term wet/dry mapping data sets from three different intermittent rivers to calculate several metrics of spatial drying patterns. We obtained streamflow data from USGS stream gages within the mapped reaches in each river, and from these data we generated a suite of standard streamflow metrics used to characterize hydrographs. We used a model selection approach to evaluate the relationship between streamflow and drying metrics. We found that streamflow metrics that describe low-flow conditions over short time spans in the 180-day period prior to wet/dry mapping could reasonably approximate spatial drying metrics (R2 = 0.45-0.75). These results indicate that continuous streamflow data collected within an intermittent river could provide useful surrogate metrics for spatial drying patterns within the river network.

Daniel Allen (Primary Presenter/Author), University of Oklahoma, dcallen@ou.edu;


Katie Costigan ( Co-Presenter/Co-Author), University of Louisiana Lafayette, costigan@louisiana.edu;


Darin Kopp ( Co-Presenter/Co-Author), University of Oklahoma, darinkopp@gmail.com;


Thibault Datry ( Co-Presenter/Co-Author), IRSTEA/IRD, France, Thibault.datry@irstea.fr;


Bernard Hugeny ( Co-Presenter/Co-Author), IRD-MNHN, Paris, France, hugueny@mnhn.fr;


Dale Turner ( Co-Presenter/Co-Author), The Nature Conservancy, dturner@tnc.org;


Gita Bodner ( Co-Presenter/Co-Author), The Nature Conservancy, gbodner@tnc.org;


Timothy Flood ( Co-Presenter/Co-Author), Friends of the Agua Fria National Monument, tjflood@att.net;


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11:00 - 11:15: / 308 PREDICTING FLOW PERMANENCE IN THE URBAN SOUTHWEST

5/23/2016  |   11:00 - 11:15   |  308

PREDICTING FLOW PERMANENCE IN THE URBAN SOUTHWEST Austin Texas is one of the fastest growing regions in the country, and is subject to a fairly hostile climate for stream ecosystems. City staff have been collecting benthic macroinvertebrate and diatom data in 45 different streams around the city since the mid-90’s, amassing a robust but highly variable data set. Flow permanence was hypothesized to be a key factor controlling taxa distributions, and previous work had generated a comprehensive physiographic data set that could be used in a random forest process to predict the flow permanence index score of a specific location. A preliminary model was developed using drainage area, impervious cover, slope, soil, wastewater sources and hydrogeologic inputs that can be applied at the reach scale to any stream in the Austin-area stream network. Error rates generated using a series of test and training reaches and a range of diagnostic tools were relatively low, resulting in a tool that will greatly improve regional bioassessment resolution and the ability to more accurately characterize and therefore manage water resources.

Abel Porras ( Co-Presenter/Co-Author), City of Austin, abel.porras@austintexas.gov;


Mateo Scoggins (Primary Presenter/Author), City of Austin, mateo.scoggins@austintexas.gov;


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11:15 - 11:30: / 308 PATTERNS OF ORGANIC MATTER PROCESSING IN SURFACE AND SUB-SURFACE HABITATS OF GROUNDWATER-INFLUENCED INTERMITTENT STREAMS

5/23/2016  |   11:15 - 11:30   |  308

PATTERNS OF ORGANIC MATTER PROCESSING IN SURFACE AND SUB-SURFACE HABITATS OF GROUNDWATER-INFLUENCED INTERMITTENT STREAMS In naturally intermittent streams, groundwater can play an important role in maintaining base flow and thus sustaining aquatic habitats. However, the importance of groundwater-surface water connectivity for maintaining key ecosystem processes, such as organic matter processing, is not well understood. We deployed leaf-litter packs (fine- and coarse-mesh) and cotton-strip assays in surface (riffle, pool, and dry gravel bars) and hyporheic stream habitats, at varying phases of hydrological connectivity, to better understand the importance of groundwater-surface water connectivity for driving rates of organic matter processing. Processing of leaf material was consistently greater in hyporheic than surface habitats, and both leaf and cotton processing was greater in surface habitats subject to persistent saturated conditions. Most leaf litter processing could be attributed to microbial processing, with similar leaf-mass loss in fine compared to coarse-mesh bags. Ongoing research is assessing how reduced groundwater-surface water connectivity affects the food web structure in surface and sub-surface habitats of intermittent streams.

Ryan Burrows (Primary Presenter/Author), Australian Rivers Institute, Griffith University, r.burrows@griffith.edu.au;


Nick Bond ( Co-Presenter/Co-Author), La Trobe University, n.bond@latrobe.edu.au;


Mark Kennard ( Co-Presenter/Co-Author), Australian Rivers Institute, Griffith University, m.kennard@griffith.edu.au;


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11:30 - 11:45: / 308 LINK OF STREAM MICROBIAL ACTIVITY WITH SHADING AND SEDIMENT HETEROGENEITY AND ITS SIGNIFICANCE UNDER DROUGHT STRESS

5/23/2016  |   11:30 - 11:45   |  308

LINK OF STREAM MICROBIAL ACTIVITY WITH SHADING AND SEDIMENT HETEROGENEITY AND ITS SIGNIFICANCE UNDER DROUGHT STRESS Shading and sediment structure affect vertical water flux and are key factors controlling streambed metabolism. In experimental streams we investigated the influence of these factors on community respiration (CR) and net primary production (NPP) during: an initial 6 week wet period, upon rewetting after 6 weeks of drying, and for 2 weeks post-rewetting. 16 experimental streams were either open to light or shaded and contained sediments structured either in an un-patched sand and gravel mixture or alternating patches of un-mixed gravel and sand. During the 6 week wet period, light streams had higher CR and NPP than those shaded for both sediment structures. Within hours of rewetting, CR recovered faster while NPP remain to the low value in all streams. However, 2 weeks after re-wetting, NPP increased and CR decreased compared to before drying. Light availability increased CR and NPP before and after drying. Streambed desiccation strongly stressed microbial community upon rewetting, equalizing CR and NPP rates regardless of light availability and sediment structure, however, CR and NPP in the light and unpatched streams recovered faster in the post-rewetting period.

Sanja Zlatanovic (Primary Presenter/Author), Department of Freshwater Conservation, BTU-Cottbus Senftenberg, sanja.zlatanovic@b-tu.de;


Jenny Fabian ( Co-Presenter/Co-Author), Leibniz-Institute of Freshwater Ecology and Inland Fisheries , fabian@igb-berlin.de;


Katrin Premke ( Co-Presenter/Co-Author), Leibniz-Institute of Freshwater Ecology and Inland Fisheries , premke@igb-berlin.de;


Michael Mutz ( Co-Presenter/Co-Author), Department of Freshwater Conservation, BTU-Cottbus Senftenberg, m.mutz@b-tu.de;


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11:45 - 12:00: / 308 STREAM DRYING UNDER CLIMATE CHANGE IN THE UPPER COLORADO RIVER BASIN: HOW WILL LOW FLOWS SHAPE FUTURE RIPARIAN VEGETATION?

5/23/2016  |   11:45 - 12:00   |  308

STREAM DRYING UNDER CLIMATE CHANGE IN THE UPPER COLORADO RIVER BASIN: HOW WILL LOW FLOWS SHAPE FUTURE RIPARIAN VEGETATION? Streamflow in the warm season has declined over the last century in the western US and is projected to continue decreasing over the next 100 years. In arid and semi-arid regions of the western US, it is likely that some perennial streams will shift to intermittent flow in response to climate-driven changes in runoff and evapotranspiration or increased water withdrawals for human uses. In this research, we addressed the following questions: how does riparian vegetation change along a perennial-to-intermittent streamflow gradient and what are the implications for vegetation change under a drying climate in the Upper Colorado River Basin (UCRB)? We sampled riparian vegetation along a wet-to-dry hydrologic gradient (perennial to intermittent and high to low elevation) in the UCRB and developed statistical relationships between flow parameters and vegetation responses. Species composition varied considerably along the hydrologic gradient and both native and perennial species were less abundant at drier sites. Last, we identified characteristic species for riparian communities along the hydrology gradient that can be used to guide management and restoration of riparian plant communities in the UCRB.

Lindsay Reynolds (Primary Presenter/Author), USDA Forest Service, lindsayreynolds@fs.fed.us;


Patrick Shafroth ( Co-Presenter/Co-Author), U.S. Geological Survey, shafrothp@usgs.gov;


LeRoy Poff ( Co-Presenter/Co-Author), Colorado State University, n.poff@rams.colostate.edu;


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