Groundwater–surface water interactions between streams and alluvial aquifers: Results from the W ollombi Brook (N SW ) study (Part II – Biogeochemical processes) Sébastien Lamontagne, Andrew L. Herczeg, John C. D ighton, Jodie L. Pritchard CSIRO Land & W ater Jaswant S. Jiwan N SW D epartment of Infrastructure, Planning and N atural Resources W illiam J. Ullman College of Marine Studies, University of D elaware Technical Report 42/03, July 2003