"Groundwater levels" refers to the amount of water present beneath the Earth's surface, typically in underground aquifers or wells. It indicates how high or low the water is within these underground sources. Full definition
These can include flood - prone areas or areas with high groundwater levels. (toiletsforpeople.com)
Since dam support structures were installed in 2008 to help colonies get started, groundwater levels there have begun to increase. (discovermagazine.com)
Under natural conditions, groundwater levels remain stable over time. (ucsusa.org)