Volcano's Many Layers Determine Richness of Hawai`i's Groundwater Res.

Fresh water cascades from a spring on a cliff face into a pool next to the Pacific Ocean near Nahiku on the island of Maui. The water comes from rain that fell at higher elevations on Haleakalā Volcano, seeped into the ground, and has traveled slowly toward the coast. (USGS photograph by Gordon Tribble from http://pubs.usgs.gov/circ/1312/c1312.pdf)