Water in underground aquifers flows in a definite direction. Just as water flows on the surface from higher elevations to lower elevations, ground water also flows "downhill". Ground water flow direction is determined by measuring water levels in wells drawing water from a particular aquifer. Ground water will flow from the higher water level elevations to lower elevations. It is the surface area directly above the flow to a well and the land uses in that area that are of major concern because of the risk of contamination from those land uses.
Contamination can filter through from the land surface to the aquifer as quickly as a few hours, or it may take many years. If the contamination gets into your water supply, you may be drinking it someday. Some areas in the Midwest have 10% of wells showing signs of serious contamination.
One of the ways we can protect groundwater is to learn more about it. Below are some misconceptions about groundwater.
Fiction: Groundwater always flows from north to south.
Fact: Depending on location, groundwater can flow in any direction, but usually follows land contours.
Fiction: Groundwater comes all the way from Canada and
Fact: Most groundwater originates as local precipitation that seeps into the ground and reaches the water table.
Fiction: Groundwater flows in underground caverns and rivers.
Fact: Groundwater flows through cracks and pores between soil and rock particles.
Fiction: Most groundwater drawn from wells has been under ground thousands of years.
Fact: Most ground water drawn from wells has been under ground a few years to a few decades.
Fiction: Groundwater is always pure because soil filters out
Fact: Harmful bacteria in water can be filtered out by soil, but many chemical pollutants are not changed and remain in the water.
In the next few years towns in Minnesota will be addressing the issue of drinking water protection by developing a plan for "Wellhead Protection." Look for more information on this in the near future and become involved in keeping your water clean.