LPRV Aquifer Management: Physical Hydrology

In late 1999, a new municipal well was installed in the southern valley to service the Century High School area.This well, Pocatello #44, has been pumping continuously ever since, because it services the entire southern valley water distribution system.
Since September, 1999, Well 44 has pumped about 900 million gallons from the southern aquifer (nearly the amount that flows annually from the upper Portneuf watersheds). All other things in the 1993-94 water balance being equal in a normal water year, the effect of Well 44 would be to bring annual total pumping to within 95% of known aquifer capacity. Clearly, this is not an accurate reflection of current conditions, because Well 44's production has reduced production in other wells. However, it is clear that aquifer capacity is limited.

Coupled with that withdrawal, aquifer storage has also been affected by below-normal precipitation in the Bannock Range during the 2000 water year. The result has been that aquifer storage in the southern aquifer has fallen to its lowest level since modern records have been kept.

On a short-term, it would appear that the southern aquifer is being exploited in a non-sustainable manner, with account debits (pumping) exceeding credits (recharge). However, a water resource can never be managed in a sustainable manner in the short-term, because of the constantly changing, dynamic conditions of recharge and demand. It is too early to tell whether southern aquifer storage will recover to normal levels during the next long-term period of normal to above normal recharge.

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