000224979 001__ 224979
000224979 005__ 20180913064132.0
000224979 0247_ $$2doi$$a10.1007/s11356-016-7715-9
000224979 022__ $$a0944-1344
000224979 02470 $$2ISI$$a000389301700082
000224979 037__ $$aCONF
000224979 245__ $$aThe influence of bottom boundary layer hydrodynamics on sediment focusing in a contaminated bay
000224979 260__ $$aHeidelberg$$bSpringer Heidelberg$$c2016
000224979 269__ $$a2016
000224979 300__ $$a15
000224979 336__ $$aConference Papers
000224979 520__ $$aUnderstanding the dynamics and fate of particle bound contaminants is important for mitigating potential environmental, economic and health impacts linked to their presence. Vidy Bay, Lake Geneva (Switzerland), is contaminated due to the outfall and overflow from the wastewater treatment plant of the City of Lausanne. This study was designed to investigate the fate of particle-bound contaminants with the goal of providing a more complete picture of contaminant pathways within the bay and their potential spread to the main basin. This goal was achieved by investigating the sediment transport dynamics, using sediment traps and radionuclide tracers, and ascertaining how local bottom-boundary hydrodynamic conditions (temperature, turbidity, current velocity and direction) influence these dynamics. Results of the study indicated that sedimentation rates and lateral advections increased vertically with proximity to the lakebed and laterally with proximity to shore, indicating the presence of sediment focusing in the bay. Hydrodynamic measurements showed the persistent influence of a gyre within the bay, extending down to the lake bed, while just outside of the bay circulation was influenced by the seasonal patterns of the main basin. Calculated mean displacement distances in the bay indicated that suspended particles can travel similar to 3 km per month, which is 1.7 times the width of the Vidy Bay gyre. This results in a residence time of approximately 21 days for suspended particles, which is much greater than previously modelled results. The calculated mobility Shield parameter never exceeded the threshold shear stress needed for resuspension in deeper parts of the bay. In such, increased lateral advections to the bay are not likely due to local resuspension but rather external particle sources, such as main basin or shallow, littoral resuspensions. These external sources coupled with an increased residence time and decreased current velocity within the bay are the precipitating factors in sediment focusing. While the spread of contaminants from the bay may occur through the transport of fine suspended sediments in shallower zones of the bay (< 60 m) by longshore littoral currents, results suggest that particle-bound contaminants are likely to remain within the bay.
000224979 6531_ $$aSediment transport
000224979 6531_ $$aContaminant
000224979 6531_ $$aRadionuclide
000224979 6531_ $$aHydrodynamics
000224979 6531_ $$aBottom boundary layer
000224979 6531_ $$aGyre
000224979 700__ $$aGraham, Neil D.$$uUniv Geneva, Dept FA Forel Environm & Aquat Sci, Geneva, Switzerland
000224979 700__ $$0246941$$aBouffard, Damien$$g164724
000224979 700__ $$aLoizeau, Jean-Luc$$uUniv Geneva, Dept FA Forel Environm & Aquat Sci, Geneva, Switzerland
000224979 7112_ $$a1st International Caparica Conference on Pollutant Toxic Ions and Molecules (PTIM)$$cCaparica, PORTUGAL$$d2015
000224979 773__ $$j23$$k24$$q25412-25426$$tEnvironmental Science And Pollution Research
000224979 909C0 $$0252474$$pAPHYS$$xU12616
000224979 909CO $$ooai:infoscience.tind.io:224979$$pconf$$pENAC
000224979 917Z8 $$x232088
000224979 937__ $$aEPFL-CONF-224979
000224979 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000224979 980__ $$aCONF