On the volcanically unique Eastern Snake River Plain, just like elsewhere, water flows from high country to low, channeled into streams, lakes, and rivers. But in the portion of the plain occupied by the Idaho National Laboratory (INL), rivers don't all flow to the ocean. Instead, something dramatically different happens. Streams like the Big and Little Lost Rivers simply disappear.

Here, where sediments deposited by the actions of wind and water overlay porous layers of basalt, rivers and streams disappear, losing their water to the Eastern Snake River Plain Aquifer. Decades later, the same water will reappear in the Magic Valley, issuing from the "Thousand Springs" stretch of the Snake River along the north canyon wall between Milner and King Hill.

The Lost River and the fascinating springs of the Magic Valley are but two features of the remarkable Eastern Snake River Plain Aquifer, which is not only the focus of this issue of the Oversight Monitor, but the primary reason that the INL Oversight Program exists.

Concern about how activities conducted at Idaho 's nuclear laboratory affect the aquifer was the driving force behind the formation of a state oversight program. No matter what issue we're considering, we're thinking about the aquifer—when we're talking about building a nuclear reactor at the site, removing waste buried in pits and trenches, closing buildings that aren't needed any more—whatever it is, to Oversight, it is about Idaho's precious resource, the Eastern Snake River Plain Aquifer.

As we struggle to find the appropriate balance between competing demands for our state's finite water resources, it makes sense to begin with the source of much of Idaho's water: the Eastern Snake River Plain Aquifer.

It's said that biology is destiny. For humans, that may be true. But for Idaho, geology is destiny, and much of that destiny is defined by the presence of the Eastern Snake River Plain Aquifer.

Rich mineral deposits brought miners to the area. Abundant water and fertile soil attracted homesteaders and farmers. Dams—many built in canyons—provide the hydroelectric power that fuels our homes, businesses, and economy. Majestic mountains and stunning landscapes lure those whose souls are fed by beauty. Idaho 's history, and its destiny, have been shaped by these resources.

Lured west with the false promise that "the rain follows the plow," homesteaders traveling the Oregon Trail crossed the Snake River Plain. Some decided to stop, gravitating to the areas where water was plentiful—next to the Snake River and its tributary streams.

In time, Idahoans developed the technology and the infrastructure to thrive whether the rain followed or not. With the addition of pumps, canals, and dams, they tapped the aquifer and farms spread out. No longer tethered to just those areas adjacent to surface water, land was cultivated throughout the Eastern Snake River Plain, molding the arid stretch into one of the most productive agricultural regions in the world.

Today, the pure, cold spring water that flows from Thousand Springs supports a thriving aquaculture (fish-farming) industry; sixty-nine percent of the trout farmed in the United States come from Idaho. Twenty-nine percent of the nation's potatoes are grown in Idaho, and the state ranks sixth in the number of cattle produced. The Eastern Snake River Plain, once little more than a dry passage to the west, now helps feed people all over the world.

Unfortunately, the rain still doesn't follow the plow. Nor does it follow the increasing demands for drinking water, habitat, agriculture, industry, production of electricity, fishing and boating, landscaping, or water left in rivers and lakes for its beauty. Demands on this vital resource continue to grow, but the amount of water available, much of it stored up in the aquifer, does not.

Some want more water for consumptive uses, such as industry, agriculture, or drinking. Others want water for production of electricity, for habitat, for recreation, or for other downstream uses.

The demands for water continue, defining Idaho 's political landscape now just as surely as geology and hydrology have always defined the Gem State's destiny. An understanding of the way the aquifer gains and loses water can help us understand the conflicts inherent in the use of water and help define that balance.

Whether you are going to define the right balance for water users or understand the complexities of contamination, it is helpful to know how the aquifer works: the principles of storage, recharge, and discharge.