2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/20/2019 | 11:45 AM - 12:00 PM | QUANTIFYING THE RECOVERY OF DENITRIFICATION FOLLOWING RESTORATION-RELATED CONSTRUCTION IN AN AGRICULTURAL WATERSHED | 250 AB
QUANTIFYING THE RECOVERY OF DENITRIFICATION FOLLOWING RESTORATION-RELATED CONSTRUCTION IN AN AGRICULTURAL WATERSHED
In agricultural streams, floodplain restoration via the two-stage ditch has been shown to improve water quality. Constructed floodplains expand bioreactive surface area and enhance nitrate-N removal via microbial denitrification, thereby reducing export to downstream ecosystems. In the Shatto Ditch Watershed (IN), 0.8 km of two-stage were constructed at the watershed outlet in 2007. In 2017 and 2018, an additional 3.7 and 2.7 km were constructed moving upstream. We quantified recovery of denitrification following stream dredging and floodplain construction using experimental incubations of stream sediments and floodplain soils, measuring dinitrogen gas concentrations using membrane inlet mass spectrometry (MIMS). We measured denitrification on stream sediments upstream, which were higher before dredging (0.22 µgN/gDM/h), but were still comparable 3 weeks post-dredging (0.15 µgN/gDM/h). Nevertheless, stream sediment rates upstream remained low relative to sediments in the 2007 two-stage reach where sediments were never dredged (0.57 µgN/gDM/h). Our research suggests that stream sediments recolonize quickly post-dredging, on the order of weeks. In contrast, floodplains soils may take longer to recover with their intermittent hydraulic connectivity, which we are exploring with continued analyses. Lags in ecosystem function are important to consider when implementing any restoration-related construction.
- Nitrogen
- Temporal
- Management
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Presenters/Authors
Shannon Speir
(), University of Notre Dame, sspeir@nd.edu;
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Jennifer L. Tank
(), University of Notre Dame, tank.1@nd.edu;
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Ursula H. Mahl
(), University of Notre Dame, umahl@nd.edu;
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