This equation was developed with the focus of incorporating groundwater into the conceptual model. Further
analysis would be required to develop a more accurate model of GW/SW behaviour.
Given that losses are represented in IQQM using a surface water flow/loss relationship, losses to groundwater were estimated by deriving a relationship between monthly SW flow and monthly change in groundwater volume. It was assumed that change in GW volume is primarily due to infiltration, and hence can be estimated using daily groundwater depths and the approximate inundation area of the GCS from Driver et al. (2004). For the purpose of this study, it was assumed that the area of recharge is approximately equal to that of the shallow underlying aquifer. A simple linear relationship was then derived for dry and wet years
separately, given that higher rates of loss are expected during dry years.