If groundwater levels continue to drop in Seabright Flats over the next five years, what is the most likely impact on the estuary?

Groundwater supplies freshwater to the estuary. If groundwater levels drop, less freshwater flows into the estuary to dilute its water and resist incoming seawater. As a result, saltwater can intrude farther into the estuary and salinity is likely to increase, matching choice D.

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