HR: 16:36h
AN: H44B-04 INVITED     [Abstracts]
TI: Riparian Zone Controls on the Chemical Dynamics of DOC-Rich Runoff from a Boreal Hillslope
AU: * Bishop, K
EM: kevin.bishop@ma.slu.se
AF: Dept. of Environmental Assessment, Swedish Univ. of Agricultural Sciences, Box 7050, Uppsala, 750 07 Sweden
AU: K”hler, S
EM: koehler@egam.tu-graz.ac.at
AF: Inst. for Technical Geology and Applied Mineralogy, Technical Univ. of Graz, Rechbauerstraáe 12, Graz, 8010 Austria
AU: Cory, N
EM: neil.cory@ma.slu.se
AF: Dept. of Environmental Assessment, Swedish Univ. of Agricultural Sciences, Box 7050, Uppsala, 750 07 Sweden
AU: Laudon, H
EM: hjalmar.laudon@sek.slu.se
AF: Dept. of Forest Ecology, Swedish Univ. of Agricultural Sciences, Forestry Faculty, Umea, 90183 Sweden
AB: The chemistry of streamwater is often quite different from that of soil water and shallow groundwater in the extensive upslope areas of many catchments, particularly with regards to the amount and character of dissolved organic carbon. The riparian zone (RZ), which runoff traverses immediately before entering the stream channel, has often been invoked to explain the differences between upslope water and the stream, as well as the changes in runoff chemistry during episodes. A "riparian convolution model" (RCM) is proposed to conceptualize the interaction of hydrology and soil in the RZ to give observed stream dynamics. A powerful feature of the RCM is that simple hydrological observations to define GW level- flow relations yield predictions of vertical profiles of RZ soil solution (which are rarely observed) from the much more common observations of stream chemistry. This model was tested on a catchment in boreal Sweden. The variation of DOC and many other constituents during runoff events could be explained by the activation of more superficial lateral flow paths in the riparian soil profiles, in accordance with the RCM. The riparian soil solution concentrations of Al and Fe could not be explained by such simple mass balances between the stream and the riparian soil profile. (Indeed a simple mass balance would not have worked for DOC if one looks at the soil profiles 12 m and 25 m from the stream). While this study demonstrates the importance of the RZ, the study also illustrates the great difficulty of quantitatively observing the interaction of hydrology and hydrochemistry.
DE: 1806 Chemistry of fresh water
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
DE: 1890 Wetlands
DE: 0400 Biogeosciences
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting