Central Maui’s groundwater has gotten saltier over the past four decades due to increased pumping of surrounding wells and a decreased amount of rainfall, USGS said.

From Maui News

“The Waiehu well is used to monitor the Wailuku area, where most of Central and South Maui’s groundwater is pumped from and then used for fire protection, domestic and irrigation purposes.

Salinity is measured at two points in the well – the “midpoint,” or where the water consists of 50 percent seawater and 50 percent fresh water; and the “freshwater lens,” or the depth at which there is only 2 percent saltwater.

Currently, the midpoint of the groundwater in the 1,020-feet deep Waiehu well is at 626 feet. In 1985, when USGS hydrologists first started monitoring the well, the midpoint was nearly 200 feet deeper, at 822 feet.”