Extended Explanation

My Aquifer > Groundwater Basics > How is an aquifer contaminated?


Deliberate disposal of waste at point sources such as landfills, septic tanks, injection wells and storm drain wells can have an impact on the quality of ground water in an aquifer.

In general, any activity which creates a pathway that speeds the rate at which water can move from the surface to the water table has an impact. In Figure 7, waste water leaking down the casing of a poorly constructed well bypasses the natural purification afforded by soil. Excessive addition of fertilizer, agrichemicals, and road de-icing chemicals over broad areas, coupled with the enhanced recharge from crops, golf courses and other irrigated land and along road ditches, are common reasons for contamination arising from non-point sources. Removal of soil in excavations and mining reduces the purification potential and also enhances recharge; in some cases, such as the Highway Pond gravel pits south of Pocatello, the water table is exposed and becomes directly vulnerable to the entry of contaminants.