Since water runoff is slowed, it has a longer time to soak in and enter the groundwater system.

For example, equilibria in groundwater systems with multiple components are achieved on timescales of millennia, if ever.

The thousands of sinkholes known as cenotes throughout the region provide access to the groundwater system.

The city's groundwater system, comprising 27 wells in southeastern Queens, accounts for about 2 percent of the city's total supply.

Water filters through soil layers before entering the groundwater system.

The runoff can also end up in groundwater systems.

This presents the possibility of a radionuclide leak into the groundwater system.

"We've never had it in our system before, and we operate the second-largest groundwater system in the nation," he said.

The ponds may overflow when it rains, and the runoff will eventually makes its way into groundwater systems.

This makes them focal points for conservation of groundwater systems.