Modelling highly variable environmental factors to assess potential microbial respiration in complex floodplain landscapes.
The hydrological exchange conditions strongly determine the biogeochemical dynamics in river systems. More specifically, the connectivity of surface waters between main channels and floodplains is directly controlling the delivery of organic matter and nutrients into the floodplains, where biogeochemical processes recycle them with high rates of activity. Hence, an in-depth understanding of the connectivity patterns between main channel and floodplains is important for the modelling of potential gas emissions in floodplain landscapes. A modelling framework that combines steady-state hydrodynamic simulations with long-term discharge hydrographs was developed to calculate water depths as well as statistical probabilities and event durations for every node of a computation mesh being connected to the main river. The modelling framework was applied to two study sites in the floodplains of the Austrian Danube River, East of Vienna. Validation of modelled flood events showed good agreement with gauge readings. Together with measured sediment properties, results of the validated connectivity model were used as basis for a predictive model yielding patterns of potential microbial respiration based on the best fit between characteristics of a number of sampling sites and the corresponding modelled parameters. Hot spots of potential microbial respiration were found in areas of lower connectivity if connected during higher discharges and areas of high water depths.
Christian Doppler Laboratory for Advanced Methods in River Monitoring, Modelling and Engineering, Institute of Water Management, Hydrology and Hydraulic Engineering, Department of Water, Atmosphere and Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 107, 1190 Vienna, Austria.
Michael
M
Tritthart
WasserCluster Lunz - Interuniversity Center for Aquatic Ecosystem Research, Dr. Carl Kupelwieser Promenade 5, 3293 Lunz am See, Austria; Institute of Hydrobiology and Aquatic Ecosystem Management, Department of Water, Atmosphere and Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Max Emanuelstr. 17, 1180 Vienna, Austria.
Nina
N
Welti
WasserCluster Lunz - Interuniversity Center for Aquatic Ecosystem Research, Dr. Carl Kupelwieser Promenade 5, 3293 Lunz am See, Austria; Institute of Hydrobiology and Aquatic Ecosystem Management, Department of Water, Atmosphere and Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Max Emanuelstr. 17, 1180 Vienna, Austria.
Elisabeth
E
Bondar-Kunze
School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Gilles
G
Pinay
WasserCluster Lunz - Interuniversity Center for Aquatic Ecosystem Research, Dr. Carl Kupelwieser Promenade 5, 3293 Lunz am See, Austria; Institute of Hydrobiology and Aquatic Ecosystem Management, Department of Water, Atmosphere and Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Max Emanuelstr. 17, 1180 Vienna, Austria.
Thomas
T
Hein
Christian Doppler Laboratory for Advanced Methods in River Monitoring, Modelling and Engineering, Institute of Water Management, Hydrology and Hydraulic Engineering, Department of Water, Atmosphere and Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 107, 1190 Vienna, Austria.
Helmut
H
Habersack
Connectivity; Danube River; Floodplains; Gauge transformation; Hydrodynamic numerical modelling; Sediment respiration
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