Evaluation of existing and new equations to quantify coastal fresh groundwater discharge

Abstract:

Coastal groundwater discharge is important for coastal hydrology and ecology but is also often difficult to quantify and highly uncertain. There are a number of equations that can be used to estimate discharge but these have several limitations and have not been adopted widely. We have recently published a large number of numerical models of coastal groundwater discharge. Here we use these model results to evaluate existing and develop new equations for predicting coastal groundwater discharge. The aim is to provide an accessible method for the prediction of discharge in areas where no data is available and to provide a method for quality control and scaling up estimates in areas where discharge data is available. We explore a new combination of seepage and groundwater flow equations that ensures that terrestrial and submarine discharge estimates are consistent with terrestrial fresh water budgets. We also discuss new empirical equations that are calibrated to numerical model results and methods to scale up point data to spatially integrated estimates.