My Aquifer > Aquifer Protection in the LPRV > Why is our aquifer in need of protection?


The gradual deterioration in water quality which has been occurring over the last 15 to 30 years (see chloride trends and nitrate trends) and more recently (see TCE plume and leaking underground tanks) provide ample evidence that the aquifer is being impacted by pollution originating at or near the land surface. If the sources of these contaminants (septic systems, storm water runoff, hazardous materials / fuels) are not controlled, the rate of water quality degradation will likely accelerate and / or other, serious pollution threats will develop that will have to be dealt with through remediation.

The lower Portneuf Valley aquifer is vulnerable because of several factors:

1) varied urban, residential, industrial, and agricultural land uses with the potential to contaminate the water supply occur directly over the aquifer;

2) water and contaminants originating at the surface can move quickly to the water table because the aquifer has minimal natural protection (thin soil cover, shallow water table, highly permeable Bonneville gravels between the surface and water table);

3) numerous artificial sources of recharge associated with urban / residential land uses (drain wells, ditches, septic leach fields) accelerate the movement of contaminants to the water table;

4) the highly permeable aquifer spreads contaminants rapidly, making it difficult to clean up contamination once it has entered the aquifer.

In addition, the lower Portneuf Valley aquifer and its immediate tributary aquifers comprise the effective sole drinking water source for Pocatello, Chubbuck, and northern Bannock County. All of these factors also exist in the Rathdrum Prairie aquifer, where for the past 20 years, proactive management approaches have been developed to provide enhanced ground water protection against contaminant threats related to urban, residential, and commercial development. These management approaches were implemented because the same kinds of trends in water quality that the lower Portneuf aquifer is experiencing were documented in the Rathdrum aquifer and future water quality was projected to degrade with continued development.