The influence of offshore storm waves on beach groundwater dynamics and salinity in a sandy ocean beach
Field observations of the response of the salinity structure in a sandy beach to oceanic fluctuations during a 15-day monitoring period are presented and discussed. There was no observable response of the salinity structure to either the semi-diurnal or neap to spring tidal cycles. During the monitoring period there was an increase in significant wave heights up to 4.5m over a period of about 4 days which resulted in a pulse in shoreline water levels due to wave setup. This induced a significant response in both the groundwater levels and the location of the salt-freshwater mixing zone. The findings have important implications for the quality of coastal groundwater resources and in particular for chemical reactions occurring within the vicinity of the mixing zone.
Proc. 29th Intl. Conf. on Coastal Engineering