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Sediment and phosphorus contributions from eroding banks in a large intensively managed watershed in western Iowa, United States
Journal article   Open access   Peer reviewed

Sediment and phosphorus contributions from eroding banks in a large intensively managed watershed in western Iowa, United States

Forrest F Williams, Peter Moore, Jade V Allen, Thomas Isenhart, John T Thomas, John L Kovar and Keith Schilling
Journal of the American Water Resources Association, Vol.60(1), pp.148-162
02/2024
DOI: 10.1111/1752-1688.13164
url
https://doi.org/10.1111/1752-1688.13164View
Published (Version of record) Open Access

Abstract

In this study, a new remote sensing tool was used in conjunction with sampling of river bank sediments to map channel migration patterns and estimate the net contribution of bank erosion to the sediment and phosphorus (P) budget of the Nishnabotna River in southwestern Iowa. Between the years 2009 and 2018, we found that at least 1.81 ± 0.57 × 107 Mg of sediment and 8.26 ± 2.5 × 103 Mg of P entered the Nishnabotna River due to channel migration. This equates to 0.87 Mg of sediment per meter of channel per year and 0.40 kg of P per meter of channel per year. Barring additional deposition elsewhere in the river corridor, these values represent as much as 77% of annual suspended sediment and 46% of the annual P export from the watershed. Our results also indicate that the contribution of net sediment and P volume loss by stream order increases sharply from third to sixth order, even though the total channel length is much smaller in the higher orders. These results suggest that bank erosion is an important source of sediment and P within the watershed and that future attempts to decrease riparian exports of sediment and P should focus on high-order reaches. This article is published as Williams, Forrest F., Peter L. Moore, Jade V. Allen, Thomas Isenhart, John T. Thomas, John L. Kovar, and Keith Schilling. "Sediment and phosphorus contributions from eroding banks in a large intensively managed watershed in western Iowa, United States." JAWRA Journal of the American Water Resources Association (2023). doi:10.1111/1752-1688.13164. Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
 Water Quality DegreeDisciplines::Physical Sciences and Mathematics::Earth Sciences::Sedimentology DegreeDisciplines::Physical Sciences and Mathematics::Environmental Sciences::Natural Resources Management and Policy erosion phosphorus sediment transport

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