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Aquifers, underground “lakes” or concentrations of water, contain the lion’s share of the world’s water supply, perhaps as high as 97 percent of it. Indeed, the Ogallala aquifer that underlies Nebraska, Kansas, Oklahoma, Colorado, New Mexico, Texas, South Dakota, and Wyoming contained an estimated one quadrillion gallons of water in 1980; since then, the water table has dropped by about two feet per year. While water withdrawal via well does not necessarily pose a risk to that water supply (except in terms of depleting the aquifer itself), contaminants can seep into the ground (and do so faster in already saturated ground). Such underground water stores typically recharge through areas of soil and/or rock with high porosity. Wetlands are another important source of “free” water filtration and biodiversity that has been largely eliminated in favor of human settlements, though recent legislation combined with grassroots efforts may slowly reverse this trend. In fact, New York State, in trying to cope with pollution issues in the New York City watershed, found that watershed management is a viable and economically attractive alternative to water treatment plants.
