Beyond Stationarity: Influence of Flow History and Sediment Supply on Coarse Bedload Transport

Understanding how river bedload responds to climate and land use changes water resource management initiatives is critical in developing sustainable approaches management. Passive monitoring techniques permit investigation of interannual dependencies transport high resolution, including sediment supply factors. Here, seismic impact plate records are processed using a probabilistic model BedLoad from Impact Plates derive 5-year data set at 5-min intervals for the lower River Avon, Devon, UK. For years that range very dry wet, annual coarse yields estimated vary through two orders magnitude with wide prediction intervals. The most effective discharge occurs consistently about one-third bankfull flow, morphologically “subbarfull” stage, result hysteretic trends falling limb this non-threshold channel. A two-phase rating curve revealed variable related “bulge” during in-bank flows, giving way near-linear trend overbank flows. component predicted well sensitivity style metric combines cumulative duration competent flows magnitude-duration product near-threshold defining field-scale exemplar “stress history.” Further, relative proportion yield relates strongly wetness previous year. High multiyear reveal controls on dynamics unique site's hydrogeoclimatic context position basin. holds promise generating “type sites” behavior improving aquatic biodiversity sustainability