My Aquifer > Groundwater Basics > How much more water can our aquifer supply?
Figure 12 shows a summary of the main inflows, outflows, and pumping withdrawals from the northern and southern portions of the lower Portneuf aquifer, as determined from a detailed water balance analysis performed in 1994 and recently updated. As of 1999, the total pumping withdrawals by the cities of Pocatello and Chubbuck exceeded 6.2 billion gallons annually. Thus, about 80% of the aquifer's water capacity is already tapped.
The full report describing the manner in which aquifer water balance was determined is available at the Idaho Geological Survey's web site.