Journal article
FINE-GRAINED SEDIMENT AND PHOSPHORUS STORAGE IN A SUSPENDED-LOAD-DOMINATED, ALLUVIAL CHANNEL
JOURNAL OF THE ASABE, Vol.65(5), pp.1149-1162
01/01/2022
DOI: 10.13031/ja.14847
Abstract
In-channel storage of both fine sediment and sediment-bound phosphorus has been recognized as potentially large contributors to respective watershed loads, yet they are rarely quantified in the field. In this field-based study, we quantified and characterized in-channel fine sediment and total phosphorus (TP) storage within a third-order stream. We hypothesized storage to be significant within the context of watershed-scale sediment and TP loads and that storage trends are influenced by channel characteristics and hydraulics. In May 2015, the volume of stored in-channel sediment was esti-mated within a 13.5 km stretch of Walnut Creek, an alluvial stream draining an agriculturally dominated watershed in Jasper County, Iowa, USA. Storage volume was estimated in-field through a series of 240 transects which were stratified across reaches of the varying channel and hydraulic conditions (e.g., sinuosity, stream power). Overall storage volume was broken down into feature classes (e.g., point bars) based on in-channel depositional processes. Following in-field quantifi-cation, feature class sediment samples were collected and analyzed for physical properties (e.g., bulk density) and TP con-centration. Physical and chemical analyses, coupled with in-field volume estimation, allowed for watershed-scale masses of in-channel sediment and TP to be calculated and then placed within the context of respective annual loads. Sediment and TP were estimated to be stored at-2.7 Mg m-1 and 0.7 kg m-1, respectively. Sinuous reaches exhibited significantly greater sediment storage volume (p < 0.001) and depth (p < 0.001) versus straight reaches. Reach sinuosity exhibited a significant positive correlation (p = 0.03) with storage mass and represented the most effective storage predictor. The majority of storage mass (72%) was represented by colluvial material accumulations at the streambank toe. Loose bed sediment was the second greatest contributor to storage mass (18%), with the remaining feature classes (e.g., bars) representing a com-bined-10%. Sediment storage mass was-3.25 times greater than the watershed suspended sediment load for 2015. The TP mass was found to be nearly equal to the respective watershed load for 2015. In-channel sediment and TP storage masses within Walnut Creek were found to be significant in comparison to respective annual loads, and thus storage is expected to play a significant role in respective watershed routing, loading, and the overall budgets of these parameters. Though chal-lenging, quantification of in-channel fine sediment and TP storage is necessary to relate source contributions (e.g., stream -bank erosion) to watershed loads and is critical to account for interannual sediment and TP export.
Details
- Title: Subtitle
- FINE-GRAINED SEDIMENT AND PHOSPHORUS STORAGE IN A SUSPENDED-LOAD-DOMINATED, ALLUVIAL CHANNEL
- Creators
- William Beck - Iowa State UniversityThomas Isenhart - Iowa State UniversityPeter Moore - Iowa State UniversityKeith Schilling - University of IowaRichard C. Schultz - Iowa State UniversityKevin Cole - National Laboratory for Agriculture and the EnvironmentMark D. Tomer - National Laboratory for Agriculture and the Environment
- Resource Type
- Journal article
- Publication Details
- JOURNAL OF THE ASABE, Vol.65(5), pp.1149-1162
- Publisher
- Amer Soc Agricultural & Biological Engineers
- DOI
- 10.13031/ja.14847
- ISSN
- 2769-3295
- eISSN
- 2769-3287
- Number of pages
- 14
- Grant note
- 2013-67019-21393 / Agriculture and Food Research Initiative (AFRI) from the United States Department of Agriculture, National Institute of Food and Agriculture
- Language
- English
- Date published
- 01/01/2022
- Academic Unit
- Earth and Environmental Sciences; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984383315302771
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