Binley教授,是英国兰卡斯特大学教授,水文地球物理领域的知名科学家。他是Water Resources Research、Water Resources Research and
Vadose Zone Journal、Journal of Hydrology and Quarterly Journal of
Engineering Geology and Hydrogeology等学术期刊副主编,AGU水文地球物理委员会主席(2003-2008) 和Fellow(2013年当选)。 学术报告摘要:
In groundwater-fed catchments, there is widespread
recognition of the threat to surface water quality caused by rising
concentrations of nitrate in groundwater. At the interface of groundwater and surface water, biogeochemical
conditions may exist to alleviate the threat of emerging nutrient rich
groundwater, however, the spatial and temporal controls of such conditions
remains an active area of research. We report here on the results of two large UK-based projects examining
the key drivers of nutrient transport to lowland rivers. In a study reach of the River Leith in
Cumbria, detailed experimental investigations has led to a conceptualisation
of the spatial patterns of water fluxes and their influence on biogeochemical
conditions. Under baseflow, the
quantification of vertical and horizontal water fluxes, was achieved through
a series of Darcian flow estimates coupled with in-stream piezometer tracer
dilution tests. These data, enhanced
by multi-level measurements of chloride concentration in river bed pore water
and water-borne geophysical surveying, reveal a localized connectivity to
regional groundwater that appears to suppress the hyporheic zone. Multi-level
samples of nitrate in shallow ground/hyporheic water, coupled with results from
push-pull tracer tests demonstrate the linkage between hydrological setting
and biogeochemical conditions. Investigations of groundwater-surface water exchange under storm
events reveal the dynamic nature of hydrological pathways and the occurrence
of flow path reversal in the hyporheic zone. In a second study area – the Hampshire Avon – we investigated the
hydrogeological controls on nutrient transport to a number of study
reaches. Using baseflow index (BFI) as
a simple measure of regional groundwater contribution we analysed the effect
of stream ‘flashiness’ on in-stream concentrations of nitrate and dissolved
organic carbon (DOC). Using data from 6 study reaches, covering 3 contrasting
hydrogeological settings, our results show a non-linear negative correlation
between DOC: nitrate molar ratio and BFI, suggesting low potential for
in-stream uptake of inorganic forms of nitrogen in baseflow dominated
catchments. Our analysis also reveals significant seasonal variations in DOC:
nitrate transport and highlights critical periods of nitrate export. Future
work should determine whether the results reported here are transferable to other
agricultural, lowland catchments. |