All About Groundwater

what is groundwater
Posted: March 8, 2018
Category: Water
Tags: aquifer, crops, e-coli, groundwater, rain, water, watershed

Don’t take groundwater for granted.  Life as we know it would be impossible without it!

Groundwater is the water that fills the cracks, voids and other openings in soil, sand and bedrock. The level of groundwater when measured is referred to as the water table.  Groundwater is replenished by rain and snow melt percolating down from the surface to recharge the aquifers and surface water.  Sand, clay and rock filter out contaminants as this water journeys through the ground making the water safer to drink.  With the recent droughts that have been experienced worldwide this recharge is being substantially reduced and water tables are dropping.  In severe cases, like Cape Town, South Africa, where they have been experiencing a drought for the last few years, “Day Zero” – the day the taps run dry, is projected to be April 12, 2018.

Groundwater is vulnerable to contamination from materials deposited on the ground surface.  These pollutants can move through the soil and end up in the groundwater.  Pesticides, fertilizers, toxic substances from mining sites, leaky underground storage tanks and improperly maintained septic systems are a few examples of threats to groundwater reserves.  Animal waste in rural areas can be a source of e-coli contamination.  In most areas water collected in storm sewers are redeposited directly into our watersheds without any treatment whatsoever.

Drinking contaminated groundwater can have serious health effects even causing death. If contaminated groundwater is used to irrigate food crops, the food can become inedible and toxic if consumed.  Several recent cases of vegetable being a source of e-coli, most recently romaine lettuce.groundwater uses

The average person uses 50 to 120 gallons of water every day for a variety of uses such as drinking, bathing, cooking and washing clothes. In Canada, if you live in a small to medium size city, chances are one in three that you rely on groundwater on a daily basis.  If you live in a rural area, the chance of relying on groundwater is more than 70%, with many homes having private wells.  Regular testing of the groundwater for possible contaminants is vitally important.  Municipalities using groundwater regularly test for contamination as failure to do so can have disastrous results. In Walkerton in 2000, 26% of the population got sick and seven people died when proper monitoring wasn’t carried out. . 

Regular testing of your water well is extremely important as the water quality can change frequently.  You should do this at least once a year and also if there is a change in odor, taste or smell.  Remember, if you own the well, you are responsible for maintaining it properly.

Regular monitoring of the amount of groundwater available is also a component of the testing necessary to ensure a reliable water supply.  This is accomplished by installing groundwater wells and monitoring the water levels in them.  Heron Instruments manufactures several different types of instrumentation which can be employed to accomplish this and give a good overview of the health of your aquifer.   

Water Level Metersdipper-t-bag

The dipper-T  incorporates a graduated tape in either metric or imperial units, installed on a reel with a probe which will indicate the presence of water.  When this probe is lowered down the well, upon reaching water a buzzer will sound and the panel will display a red light.  The depth to the water can then be measured accurately by reading the distance lowered on the tape.


The dipperLog NANO when suspended in a well will record water levels at pre-set intervals, saving the data in an internal memory.  This data can be downloaded upon retrieval of the datalogger.

Everyone needs to take an active part in defending the safety of our groundwater.  There are a few simple things everyone can do in this regard:

  • Don’t over apply pesticides, herbicides or fertilizers
  • Wash your car on your lawn or at a car wash
  • Handle hazardous substances over cement so they can be cleaned up completely
  • Contact local authorities to dispose of substances such as paint or antifreeze
  • Maintain your septic system and have it serviced regularly
  • Properly maintain your vehicle to avoid leaks
  • Do not drain your pool into the storm sewer
  • Use biodegradable soaps and cleansers in your home
  • Make sure that waste is treated properly
  • Plug or seal any decommissioned water wells
  • Clean up all pet waste and dispose of it properly
  • Don’t use excess salt to clear walkways in winter

In Ontario, Public Health Ontario Laboratories test for bacterial contamination such as coliforms and E. coli.  Your local public health unit can assist you in finding further water testing for chemical contaminants. 

We must always remain vigilant in guarding and protecting our vital groundwater reserves.

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