Author(s): J. F. Costelloe; G. Sites; J. Moreau; A. W. Western
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Keywords: Groundwater surface water connectivity; Losing; Gaining; Reaches
Abstract: Understanding the contribution of groundwater to flows in lowland rivers is critical for the sustainable management of water resources. As part of a large research project (‘Farms, Rivers, Markets') into optimising water resource and environmental benefits at the catchment scale, we use a range of hydraulic gradient and chemical data to identify the degree of groundwater interaction in the Broken River of north-eastern Victoria. Investigation of hydraulic gradients between river levels and unconfined groundwater in monitoring bores has identified gaining, losing and flow varying reaches of the Broken River. Further investigation of ionic and isotopic composition of surface water and groundwater shows that below the main storage reservoir (Lake Nillahcootie), groundwater discharge during low flow is minor despite favourable hydraulic gradients. In flow varying reaches, discharge of moderately saline regional groundwater into the river is very limited and a lens of fresh groundwater occurs close to the river channel.
Year: 2011