A Grounding in Groundwater

Groundwater is water that occupies pore space in the rock and soil layer beneath our feet, filling underground storage areas called aquifers. Groundwater slowly moves through these aquifers, going on to feed into lakes, ponds, rivers and even the ocean. This natural discharge doesn’t deplete the aquifers, as the groundwater is replenished with precipitation that soaks through the surface soil and into the saturated groundwater layer. In this manner, the water cycle helps to create and sustain natural reservoirs of water in the ground—one hundred times more water, in fact, than there is in all of the world’s rivers and lakes!

Over half of the US population relies on groundwater for domestic uses, with the country drawing an estimated 79.3 billion gallons per day in 2010. Some states depend on groundwater especially heavily—Hawai'i, Florida, Idaho, Mississippi, Nebraska, and Iowa all used groundwater for more than 75% of their public-supply withdrawals in 2010. Groundwater is also a major supplier of water for wetlands and rivers, as it is estimated that these underground water sources contribute about 40% of all stream flow in the United States.

In New Hampshire, Vermont, and Maine, up to 50% of households treat waste with septic systems, which can contribute unwanted bacteria and nutrients to groundwater supplies.  If you have a septic system, an easy way to prevent groundwater pollution in your area is to divert water runoff from downspouts and other areas away from your septic drainfield.  This will prevent the runoff water from transporting pollutants from the septic drainfield into groundwater supplies as it soaks into the ground.

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