Comparison of Surface Water?Groundwater Exchange Fluxes Derived From Hydraulic and Geochemical Methods and a Regional Groundwater Model

Intercomparison of surface water-groundwater (SW-GW) exchange fluxes at the regional scale is rarely undertaken, mainly because estimates are method and scale-dependent usually associated with large errors. In present study, we compare SW-GW calculated from a multitracer mass balance in river, an application Darcy's law using near-river piezometers surface-subsurface flow model calibrated catchment scale. estimated for 7 km long reaches along 140 Campaspe River, tributary Murray Australia. Differences found directions magnitudes by different methods. The seems most appropriate to infer temporal variability. tracer limited gaining but gives quantitative fluxes. While numerical models should overcome deficiencies some intrinsic assumptions two field-methods, regional-scale calibration subject high uncertainties simulated heads near resulting uncertainty particular, show that loosely quantified river abstractions irrigation patterns directly impact reaches, additional chemistry data improved flux estimates. crucial water management, their reliability estimate can be complexity lacking availability. Therefore, recommend comparing results easily implemented field-based