title: Storm Event Suspended Sediment-Discharge Hysteresis and Controls in Agricultural Watersheds: Implications for Watershed Scale Sediment Management.
abstract: Within agricultural watersheds suspended sediment-discharge hysteresis during storm events is commonly used to indicate dominant sediment sources and pathways. However, availability of high-resolution data, qualitative metrics, longevity of records, and simultaneous multiwatershed analyses has limited the efficacy of hysteresis as a sediment management tool. This two year study utilizes a quantitative hysteresis index from high-resolution suspended sediment and discharge data to assess fluctuations in sediment source location, delivery mechanisms and export efficiency in three intensively farmed watersheds during events over time. Flow-weighted event sediment export was further considered using multivariate techniques to delineate rainfall, stream hydrology, and antecedent moisture controls on sediment origins. Watersheds with low permeability (moderately- or poorly drained soils) with good surface hydrological connectivity, therefore, had contrasting hysteresis due to source location (hillslope versus channel bank). The well-drained watershed with reduced connectivity exported less sediment but, when watershed connectivity was established, the largest event sediment load of all watersheds occurred. Event sediment export was elevated in arable watersheds when low groundcover was coupled with high connectivity, whereas in the grassland watershed, export was attributed to wetter weather only. Hysteresis analysis successfully indicated contrasting seasonality, connectivity and source availability and is a useful tool to identify watershed specific sediment management practices.
authors.affiliation: Crops, Environment and Land Use Programme, Teagasc, Johnstown Castle, Wexford, Ireland.|Geography, School of Social Sciences, University of Dundee , Dundee, DD1 4HN, Scotland, U.K.
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Sherriff
authors.affiliation: Geography, School of Social Sciences, University of Dundee , Dundee, DD1 4HN, Scotland, U.K.
authors.forename: John S
authors.initials: JS
authors.lastname: Rowan
authors.affiliation: Crops, Environment and Land Use Programme, Teagasc, Johnstown Castle, Wexford, Ireland.
authors.forename: Owen
authors.initials: O
authors.lastname: Fenton
authors.affiliation: School of Geography and Environmental Sciences, Ulster University , Coleraine, Co. Derry, BT52 1SA, U.K.
authors.forename: Philip
authors.initials: P
authors.lastname: Jordan
authors.affiliation: National Centre for Engineering in Agriculture, University of Southern Queensland , Toowoomba, Australia.
authors.forename: Alice R
authors.initials: AR
authors.lastname: Melland
authors.affiliation: Agricultural Catchments Programme, Crops, Environment and Land Use Programme, Teagasc, Johnstown Castle, Wexford, Ireland.
authors.forename: Per-Erik
authors.initials: PE
authors.lastname: Mellander
authors.affiliation: Crops, Environment and Land Use Programme, Teagasc, Johnstown Castle, Wexford, Ireland.
authors.forename: Daire Ó
authors.initials: DÓ
authors.lastname: hUallacháin
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments; D062070:Hydrology / Q000379:methods*; D045483:Rivers; D012987:Soil; D014887:Weather
chemical_list: D012987:Soil