title: Estimating sediment and caesium-137 fluxes in the Ribble Estuary through time-series airborne remote sensing.
abstract: High spatial and temporal resolution airborne imagery were acquired for the Ribble Estuary, North West England in 1997 and 2003, to assess the application of time-series airborne remote sensing to quantify total suspended sediment and radionuclide fluxes during a flood and ebb tide sequence. Concomitant measurements of suspended particulate matter (SPM) and water column turbidity were obtained during the time-series image acquisition for the flood and ebb tide sequence on the 17th July 2003 to verify the assumption of a vertically well mixed estuary and thus justifying the vertical extrapolation of spatially integrated estimate of surface SPM. The ¹³⁷Cs activity concentrations were calculated from a relatively stable relationship between SPM and ¹³⁷Cs for the Ribble Estuary. Total estuary wide budgets of sediment and ¹³⁷Cs were obtained by combining the image-derived estimates of surface SPM and ¹³⁷Cs with estimates of water volume from a two-dimensional hydrodynamic model (VERSE) developed for the Ribble Estuary. These indicate that around 10,000 tons of sediment and 2.72 GBq of ¹³⁷Cs were deposited over the tidal sequence monitored in July 2003. This compared favourably with bed height elevation change estimated from field work. An uncertainty analysis on the total sediment and ¹³⁷Cs flux yielded a total budget of the order of 40% on the final estimate. The results represent a novel approach to providing a spatially integrated estimate of the total net sediment and radionuclide flux in an intertidal environment over a flood and ebb tide sequence.
authors.affiliation: Atkins Limited, 200 Broomielaw, Glasgow G14RU, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Wakefield
authors.forename: A N
authors.initials: AN
authors.lastname: Tyler
authors.forename: P
authors.initials: P
authors.lastname: McDonald
authors.forename: P A
authors.initials: PA
authors.lastname: Atkin
authors.forename: P
authors.initials: P
authors.lastname: Gleizon
authors.forename: D
authors.initials: D
authors.lastname: Gilvear
mesh_terms: D002586:Cesium / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000032:analysis*
chemical_list: D002586:Cesium