Spatiotemporal variability of stream Phosphorus in an agroindustrial watershed
Abstract
In agricultural watersheds, rainfall and watershed characteristics (e.g., agricultural practices and topography) drive the transport of phosphorus (P) from land surfaces to water bodies, where excess P often leads to eutrophication. Yet, how P concentrations in streams change with the long-term climate variability still remains unclear. Here we analyze observed and simulated Total P and Soluble Reactive P concentrations and loads in the Sangamon River Basin in Central Illinois over two decades (1999-2018). We compare the spatial distribution of precipitation together with adopted agricultural management practices and topography to the riverine P concentrations and loads. In addition, we characterize the intra/inter-annual variability of P loads as well as changes in P concentration during dry and wet periods. We employ the Soil and Water Assessment Tool (SWAT) with a new module that simulates in-stream P processes to distinguish between recent P delivery to the stream and the legacy effects in streams. We then estimate P yields in the basin for the short-term future (2040) under future climate scenarios with downscaled precipitation products considering various agricultural management practices. Preliminary results show that in the long term, the increase in total P concentration corresponds to the increase in precipitation; this phenomenon is more prominent during the growing season in agricultural watersheds like the Sangamon River above Fisher and Monticello. However, at Riverton, where P loads are dominated by industrial point sources, the role of precipitation is less significant. Improved understanding of such relationships between climate variability and basin-scale P yields will help quantify risks posed by changing water quality within Food Energy Water System (FEWS). Specifically, knowledge generated by this study will be utilized within an Integrated Technology- Environment -Economics Modelling (ITEEM) framework to assess the resilience of Corn Belt FEWS.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H11I1606N
- Keywords:
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- 1632 Land cover change;
- GLOBAL CHANGE;
- 1834 Human impacts;
- HYDROLOGY;
- 1847 Modeling;
- HYDROLOGY;
- 1879 Watershed;
- HYDROLOGY