By Kerry Sievert and Valerie Lewis
Purpose:
To increase student understanding of groundwater and the effects of pollution upon that groundwater.
Background:
- Groundwater is fresh water, found in the soil and stored in the tiny pores between rocks and soil particles. Precipitation, once having soaked into the ground, may remain in the ground, come to surface filling bodies of water, come to the surface as through a spring, or be pumped as from a well.
- The degree to which the soil particles and rocks hold groundwater is dependent upon the size and shape of the particles. This characteristic is referred to as the porosity of the soil.
- Groundwater that is found immediately below the surface of the land is called the unsaturated zone or the zone of aeration. Found in this layer are water and air in pores. Below this zone is the zone of saturation, in which all pores and rock fractures are filled with water. The top of the saturated zone is referred to as the water table.
- Permeability is the ability of water to move through the soil or rock material. If water can move rapidly through the rock material (pores and fractures), an aquifer forms. Water which accumulates in an aquifer can be accessed by a well for human use.
- Groundwater can be contaminated when surface water, which recharges an aquifer is polluted or when hazardous substances soak through the soil into the groundwater. A contaminant that dissolves in groundwater could potentially pollute wells from which drinking water is pumped.
- Cleaning up groundwater is a difficult task because the structure of the groundwater system and aquifers is complicated and the contaminants are invisible to the naked eye.
Unit Overview:
The following unit of instruction should involve 7-8 class periods in both science and math classes. Students will discuss the implications of population growth upon the environment. Among the many ideas generated, the increased use of garbage and the disposal of waste materials in the landfill will be investigated. Several lessons will help students understand groundwater and aquifers. The unit will conclude with students assessing the importance of groundwater to people, and the sources of pollution impacting the groundwater, and the effects of groundwater pollution upon the environment and the human population.