My Aquifer > Groundwater in the LPRV > What is the Highway Pond and why all the fuss?


Some areas in the valley pose site-specific risks. The Highway Pond gravel pit is one such example. At this location, the water table is exposed when the ground water table rises. In general, any area in which the protective soil cover is missing poses a greater risk to ground water because activities at the surface can bypass the filtering properties of the soil and directly move to the water table throughout the highly permeable Bonneville gravel.

Visit the hydrology section of the Digital Atlas of Idaho to learn about the Bonneville Flood.

This photo shows the Highway Pond in 1996, the most recent time when the water table rose significantly. Note that recreationalists have direct access to the water table, and that automobiles are driven near and, in some cases, into the water. The water visible here and in subsequent photos is part of the aquifer and is constantly moving through the Pond from roughly southeast to northwest. Therefore, any contaminant introduced in the Highway Pond will enter the municipal water supply. Because of this fact, the Highway Pond has generated considerable interest and debate over its impact on the aquifer. Although no definitive link has been established, a local landowner contends that his well has been contaminated by coliform bacteria originating in the Pond. A draft report is being prepared on what is known and not known of the Highway Pond's influence on local ground water.



Uncontrolled public access to the Highway Pond gravel pit, coupled with an attractive incentive to frequent the pit (in the form of a stocked trout fishery), has led to numerous cases of illegal dumping in the pit. This photo shows one of three documented examples of lead-acid storage batteries found in the gravel pit.

Other occurrences include oil dumped on the gravel near the water, trash, hazardous chemical drums, scrap metal, discarded tires, animal feces, fishermen relieving themselves other than where portable toilets are located, portable toilets dumped into the water, and lax environmental controls on excavation subcontractors operating in the pit in the past.

Vandalism and property destruction has also been a problem, including breaking of fences and trespassing around barricades erected to control public access.

Off-road vehicles - both two and four-wheel - have been impossible to exclude from the gravel pit, even when effective barricades have been installed. As is evident in this photo, the mentality of some who are inclined to disregard authority leads one to wonder about what besides tires is put into a water body, "because it's there."

Perhaps the greatest risk posed by a combination of uncontrolled ingress to the pit, direct access to the water table, and the "gravel pit mentality" which an open borrow pit conveys, is the possibility that accidental or intentional releases of hazardous material to the aquifer can occur. This photo is from a demonstration conducted in November, 1999 by an individual using empty plastic drums; it was intended to convey the ease with which a large quantity of material could be brought into the pit and disposed directly to the water table.

The Idaho Transportation Department, which operates the gravel pit, has taken steps since becoming aware of these issues, to adopt a proactive management approach and curtail vehicular access to the pit; in addition, Idaho Fish and Game, which stocks the pond, has installed portable toilets and posted signs encouraging users to respect and protect the facility.