Imagine if all the water that fell onto Maine in a single year stayed right where it landed. We would be wading through water higher than our waists! Fortunately, the 41 inches of average precipitation (both rain and snow) runs into lakes, rivers, ocean, or into underground storage areas called aquifers. Aquifers are underground reservoirs. The water that reaches these chambers is usually much cleaner than the water of reservoirs at the earth's surface. Almost no bacteria live in aquifers. Many pollutants are filtered out as the water passes through the soil on its way to the aquifer. Unlike surface reservoirs like Sebago Lake, there is no silty mud to cloud the water, no pollution from boaters, and no evaporation of the water supply by the sun.
To tap the groundwater in an aquifer, wells are dug until they reach the top layer of the aquifer, the water table. The water table is not flat as its name makes it seem. It has peaks and valleys that echo the shape of the land above it. When a lot of water is pumped from an aquifer, or when there is a dry spell, the water table sinks lower.
Water flowing into recharge areas--land covered with soil and trees-- refills the aquifer. Bogs and swamps may absorb and store water that later slowly drains into aquifers. When recharge areas and wetlands are replaced by parking lots and highways, less water reaches the aquifer. Oil and road salt from paved roads may trickle down with rain and snowmelt and pollute an aquifer.
Sometimes an aquifer pops out the side of a hill as a spring. You can think of a spring as a newborn stream. Not many animals live in its water because it doesn't yet contain enough oxygen to support much life. Water mites, scuds or "sideswimmers," black fly or caddis fly larve, and occasionally beetles, snails, and salamanders may live in the cold water. Minks, raccoons, deer mice, and jays use springs as people do, for watering holes.
About seventy percent of the earth's surface is covered with water. Only one percent is fresh water, flowing through rivers, lakes, and underground streams. Much of that has already been polluted by humans. That is why aquifers and springs--natural sources of clean water-- are so important.
Water not only covers two-thirds of the earth, it floods our language as well. Make a list of all the expressions you can think that refer to water, such as: "bogged down," "swamped," "treading water," "the well's dry," "up the creek without a paddle," "swimming against the tide," etc. Then try to come up with an explanation for their origins.