More Like this

1. Exploring Silica Stoichiometry on a Large Floodplain Riverscape

   https://doi.org/10.3389/fevo.2019.00346  

   Carey, Joanna C.; Jankowski, KathiJo; Julian, Paul; Sethna, Lienne R.; Thomas, Patrick K.; Rohweder, Jason (September 2019, Frontiers in Ecology and Evolution)
2. Large Seasonal and Habitat Differences in Methane Ebullition on the Amazon Floodplain

   https://doi.org/10.1029/2020JG005911  

   Barbosa, Pedro M.; Melack, John M.; Amaral, João H. F.; Linkhorst, Annika; Forsberg, Bruce R. (July 2021, Journal of Geophysical Research: Biogeosciences)

   Abstract Tropical floodplains are an important source of methane (CH₄) to the atmosphere, and ebullitive fluxes are likely to be important. We report direct measurements of CH₄ebullition in common habitats on the Amazon floodplain over two years based on floating chambers that allowed detection of bubbles, and submerged bubble traps. Ebullition was highly variable in space and time. Of the 840 floating chamber measurements (equivalent to 8,690 min of 10‐min deployments), 22% captured bubbles. Ebullitive CH₄fluxes, measured using bubble traps deployed for a total of approximately 230 days, ranged from 0 to 109 mmol CH₄m⁻² d⁻¹, with a mean of 4.4 mmol CH₄m⁻² d⁻¹. During falling water, a hydroacoustic echosounder detected bubbles in 24% of the 70‐m segments over 34 km. Ebullitive flux increased as the water level fell faster during falling water periods. In flooded forests, highest ebullitive fluxes occurred during falling water, while in open water and herbaceous plant habitats, higher ebullitive fluxes were measured during low water periods. The contribution of diffusive plus ebullitive CH₄flux represented by ebullition varied from 1% (high and rising water in open water of the lake) to 93% (falling water in flooded forests) based on bubble traps. Combining ebullitive and diffusive fluxes among habitats in relation to variations in water depth and areal coverage of aquatic habitats provides the basis for improved floodplain‐wide estimates of CH₄evasion. 

   more » « less
3. Channel-floodplain response to changes in sediment supply and floodplain width

   Viparelli, E; Eke, E (August 2020, Taylor and Francis)

   Flow regime, sediment supply and base level control geometry and evolution of alluvial channels and floodplains. Single thread rivers subject to constant forcing can reach equi-librium conditions in which the amount of sediment deposited on the floodplain through point bar deposition and overbank sedimentation is balanced by erosion of floodplain sed-iment through channel migration. At equilibrium, floodplain slope and sediment size dis-tribution, reach-averaged channel geometry (width and depth) and channel migration rates do not change in time. In response to changes in sediment supply and floodplain width, channel geometry and migration rate, floodplain slope and size distribution are expected to evolve in space and time. Predicting this response remains an open problem for geoscien-tists and engineers. Here we use an equilibrium solution of a 1D morphodynamic frame-work of channel-floodplain evolution to investigate how equilibrium conditions change as a function of sediment supply and floodplain width. Sediment is modeled here as a mix-ture of two grain sizes, sand and mud. Channel migration rate and width are functions of near-bank flow properties and floodplain characteristics. We zero the model using input parameters based on the pre-1930 ~ reach of the Minnesota River from Mankato to Jordan, USA, where data is available for proper field scale model verification. We then use the validated model to quantify the long-term (equilibrium) response of the schematic reach to changes in sediment supply magnitude and size distribution, as well as to changes in floodplain width. 

   more » « less
4. Channel-floodplain response to changes in sediment supply and floodplain width

   Viparelli, E; Eke, E (August 2020, Taylor and Francis)

   Flow regime, sediment supply and base level control geometry and evolution of alluvial channels and floodplains. Single thread rivers subject to constant forcing can reach equi-librium conditions in which the amount of sediment deposited on the floodplain through point bar deposition and overbank sedimentation is balanced by erosion of floodplain sed-iment through channel migration. At equilibrium, floodplain slope and sediment size dis-tribution, reach-averaged channel geometry (width and depth) and channel migration rates do not change in time. In response to changes in sediment supply and floodplain width, channel geometry and migration rate, floodplain slope and size distribution are expected to evolve in space and time. Predicting this response remains an open problem for geoscien-tists and engineers. Here we use an equilibrium solution of a 1D morphodynamic frame-work of channel-floodplain evolution to investigate how equilibrium conditions change as a function of sediment supply and floodplain width. Sediment is modeled here as a mix-ture of two grain sizes, sand and mud. Channel migration rate and width are functions of near-bank flow properties and floodplain characteristics. We zero the model using input parameters based on the pre-1930 ~ reach of the Minnesota River from Mankato to Jordan, USA, where data is available for proper field scale model verification. We then use the validated model to quantify the long-term (equilibrium) response of the schematic reach to changes in sediment supply magnitude and size distribution, as well as to changes in floodplain width. 

   more » « less
5. Floodplain Buyouts and Municipal Finance

   https://doi.org/10.1061/(ASCE)NH.1527-6996.0000380  

   BenDor, Todd K.; Salvesen, David; Kamrath, Christian; Ganser, Brooke (August 2020, Natural Hazards Review)