21-3 Contributions to Suspended Sediment and Total Phosphorus Loads from Three Distinct Holocene Alluvial Deposits Comprising Streambanks in Central Iowa, USA.
See more from this Division: SSSA Division: Soil and Water Management and Conservation
See more from this Session: Soil and Water Management and Conservation Oral I
Abstract:
Streambank stratigraphy is comprised of the Camp Creek, Robert’s Creek, and Gunder members of the DeForest Formation, with each individual member being deposited during a distinct time range during the Holocene. These members represent 11, 10, and 8% of the channel’s total eroding streambank surface area, respectively. Colluvial material on the lower portions of the streambanks represents the remaining 71% of eroding bank surface area, and is being investigated as well. Member-specific erosion rates are being quantified via erosion pins, channel cross section measurements, and terrestrial LiDAR scans. Erosion estimates are combined with member attributes (i.e., thickness, bulk density, texture, total P concentration) and times-series stream gauge station data to provide an estimate of contributions to annual suspended sediment and total P loads. Coupling temporal, site-specific streambank recession measurements and stream discharge data with time-lapse photography is assisting to identify the dominant erosional processes (e.g., hydraulic, slumping, subaerial) associated with individual members.
See more from this Division: SSSA Division: Soil and Water Management and Conservation
See more from this Session: Soil and Water Management and Conservation Oral I