Browsing by Subject "river"

Now showing 1 - 3 of 3
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    Comparison of Two Small Streams in Itasca State Park with the River Continuum Concept
    (2010-03-11) Petitti, James; Jewett, Erin; Reddy, Priyanka; Shimp, Adam
    The river continuum concept (RCC) first proposed by Vannote et al. (1980) has widely been accepted as the general template for characterizing the ecology of streams and rivers as water travels from the headwaters to much larger bodies of water. We tested the RCC on two small streams, Mary Creek and Chambers Creek in Itasca State Park. The streams chosen were both small with lentic sources, however physically the streams differ greatly in the variables we examined. We examined variables including substrate type, flow, canopy coverage, depth, width, pH and macro-invertebrate functional feeding groups to test if the two streams would fit the concept of low order streams. We found that the two streams are significantly different from each other and that Chambers varies somewhat from the RCC. Mary Creek fits the characteristics of a low order stream while Chambers Creek fits the physical characteristics of a mid order stream with some of the community composition of a low order stream. Mary Creek’s characteristics that classify it as a low order stream are the almost complete canopy coverage, narrow average width of 2.5m, shallow depth of 19cm, and substrate of rock and sand. Whereas, the characteristics that make Chambers Creek a mid order stream are little to no canopy coverage, mid size width averaging 10m, depth of 70cm, and a substrate of silt and sand. The organic matter at each location also differs, Mary Creek is comprised of coarse particulate organic matter (CPOM) and Chambers Creek is comprised of mostly fine particulate organic matter (FPOM). This organic matter is the primary nutrient source for different functional feeding groups.
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    Experimental alluvial-river and landsliding response to base-level fall
    (2020-04-24) Beaulieu, Olivia P; Wickert, Andrew D; Witte, Elizabeth D; Tofelde, Stefanie; awickert@umn.edu; Wickert, Andrew D; Saint Anthony Falls Laboratory; Department of Earth & Environmental Sciences; Universität Potsdam
    We observed the incisional response of an alluvial river to base-level fall. We conducted the experiment in a 3.9 × 2.4 × 0.4 m box that we filled with uniform 0.140±0.04 mm sand. We dropped base level by lowering the elevation of an "ocean" pool at the river outlet. As the initial condition, we cut a 10±2 cm wide channel to a steadily increasing depth, from 3±0.5 cm at the inlet, where we supplied water and sediment, to 10±1 cm at the outlet. Input water and sediment discharge were 0.1 L/s and 0.0022 L/s (including pore space), respectively. As base level fell, the river incised and migrated laterally, forming a valley with abandoned terrace surfaces and walls that failed in mass-wasting events as they were undercut. We include a control case with no base-level fall, as well as experiments with 25 mm/hr, 50 mm/hr, 200 mm/hr, 300 mm/hr, and 400 mm/hr of base-level fall. We supply georeferenced overhead photos (0.89 mm resolution, every 20 seconds), digital elevation models (DEMs, 1 mm horizontal resolution, every 15–30 minutes), videos generated from the overhead photos, mapped landslides in GIS vector area (polygon) format, and landslide attributes. Relevant code to process and plot the data, as well as further information on grain size, is available from GitHub and Zenodo.
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    Minnesota Pollution Control Agency Wild Rice Sulfate Standard Field Study: water, sediment, porewater, and observational data collected across Minnesota 2011-2013
    (2017-04-10) Myrbo, Amy; amyrbo@umn.edu; Myrbo, Amy
    This study was undertaken by the Minnesota Pollution Control Agency (MPCA) and University of Minnesota to improve the understanding of why wild rice (Zizania palustris, manoomin, psin) is observed to thrive only in waters with low sulfate (SO4), and to contribute to evaluation of Minnesota Rules 7050.0224, promulgated in 1973, which seeks to limit the exposure of wild rice to sulfate concentrations exceeding 10 mg/L. The dataset is now released as manuscripts using it are being published.