Human actions in the home, on the farm, or at work can affect both 
groundwater quality and quantity. 

Land Use

How we use and manage our land within the watershed affects the quality of local groundwater---the water we drink---for a couple of reasons:

• Water begins as precipitation (usually rain or snow) at the land surface and moves through soil and rock to become groundwater.  
  
• Usually the groundwater that you pump from your well recharges from within a few miles of the well.  

Fertilizers, pesticides, household cleaners, human and animal waste, underground storage tanks, as well as hazardous wastes can contaminate groundwater.  Nitrate contamination and pesticide contamination are discussed in more detail below.

Take a look at the land use map to the right.  What land uses might pose a risk to the groundwater resource?  Why?

How the population is distributed across the landscape (population density) may be a factor in the availability of groundwater, as well as its quality.  The areas with higher concentrations of people can pose a greater threat to groundwater quantity and quality.

The density of subdivisions not connected to a municipal sewage system can impact the quality of groundwater with nitrogen from septic systems leaching into the groundwater.  

In the same respect, the density of towns and municipalities may also negatively impact the groundwater resource.  The amount of water used or consumed for human activities impacts the quantity of the groundwater resource.  Municipal water usually comes from within one watershed and often many municipalities may draw water from the same watershed.  For example, Stevens Point, Plover, and Whiting draw groundwater from the Plover and Little Plover Rivers.  Does this watershed contain enough groundwater to meet current and future water demands? What impact does municipal use have on the quantity of groundwater available?  Groundwater quantity availability is discussed in more detail below.

Nitrate Contamination

According to research studies, the main sources for nitrate in Wisconsin and Portage County groundwater are:

• agriculture-90%
• septic systems-9%
• lawns and other sources-1%

Increasing nitrate levels in groundwater tend to follow the increase in sales of fertilizer over the last 40 years.

More information on nitrate.

Pesticide Contamination

The main sources for pesticides in groundwater are:

• agricultural applications
• home uses

In Portage County, pesticide contamination is also a concern with over 45 different pesticides being applied to crops and numerous pesticides being used around the home.  Which of these pesticides contaminates the groundwater?  Research is still being conducted on the leachability of pesticides to groundwater.

What is known is that in Portage County 40% of the private wells tested have a detection of atrazine, a herbicide used on agricultural crops.  Of this 40%, 3% exceed the Drinking Water Maximum Contaminant Level (MCL) of 3 ppm for atrazine.

More information on pesticides.

Groundwater Quantity Availability

(coming soon)