Conductivity is a key indicator for seawater contamination in coastal wells, as the difference in conductivity between seawater and fresh groundwater is very marked. See the LAWA factsheet for more information.
Greater Wellington and Wellington Water monitor the Waiwhetu Aquifer at three locations on the Petone foreshore; near to Petone wharf (‘Tamatoa’), McEwan Park, and Port Road in Seaview. There is more than one monitoring bore at each of these sites because we monitor different depths in the aquifer. This is because saltwater is denser than freshwater, and may enter the aquifer near to its base. More information on the Petone Saline Intrusion Monitoring network can be found here: Greater Wellington — Waiwhetu Aquifer.