Local aquifers close to the ground’s surface usually provide the water that emerges from local springs. This is the situation present in Poly Canyon’s case. These local aquifers are fed by larger, more extensive aquifers deeper in the earth’s surface. These principal aquifers come in many types, but the type that underlies Poly Canyon is known as an “Unconsolidated Sand and Gravel Aquifer”. Unconsolidated sand and gravel aquifers are classified by the United States Geological Survey as aquifers that have intergranular porosity and contain water primarily under unconfined or water-table conditions. These aquifers are called “unconsolidated” because there is a wide variety in grain size, rock layer thickness, and sorting of grains.

Unconsolidated Sand and Gravel Aquifers in the U.S. (Shown in Blue)