Excessive input of fine sediment and absorbed phosphorus to streams is a leading pollutant of fresh water in the United States, adversely affecting the water quality for aquatic organisms and people. The input of sediment and associated phosphorus from farmed land to streams is known to vary spatially and temporally in relation to storm events of different magnitudes and intensities, but pathways of connectivity between farmed fields and streams remain poorly understood. The proposed study will evaluate the extent to which eroded soil and sediment-absorbed phosphorus enters headwater agricultural streams through different pathways during different runoff-producing events. Sediment tracing will be based on Beryllium-7 (7Be), which is readily adsorbed onto sediment, has a short half-life, and is an excellent event-based tracer of fine sediment flux during storm events. Samples of sediment will be collected from different source pathways and from the stream and analyzed for 7Be and phosphorus concentrations. Analysis will examine how the 7Be signatures of different source pathways, along with differing phosphorus concentrations of sediment in various pathways, compares to the concentrations of 7Be and phosphorus concentrations of sediment within the stream. Results will provide insight into the specific pathways by which eroded sediment enters the stream system—knowledge that will be valuable for guiding sediment and phosphorus management in intensively managed agricultural landscapes in Illinois.
- PI: Bruce Rhoads
- PI Institution: University of Illinois at Urbana-Champaign
- September 1, 2022 – August 31, 2023