RFG 2018 Conference


Potential corrosivity of untreated groundwater in the United States

Corrosive groundwater, if untreated, can dissolve lead and other metals from pipes and other components in water distribution systems. Two indicators of potential corrosivity—the Langelier Saturation Index (LSI) and the Potential to Promote Galvanic Corrosion (PPGC)—were used to identify which areas in the United States might be more susceptible to elevated concentrations of metals in household drinking water and which areas might be less susceptible. On the basis of the LSI, about one-third of the samples collected from about 21,000 groundwater sites are classified as potentially corrosive. On the basis of the PPGC, about two-thirds of the samples collected from about 27,000 groundwater sites are classified as moderate PPGC, and about one-tenth as high PPGC. Potentially corrosive groundwater occurs in all 50 states and the District of Columbia.

What is groundwater used for?

Roughly 60 percent of global groundwater use is for irrigation; most of the rest is used in households and industry.1 Groundwater uses vary significantly by country, and partly depend on climate. In some countries with abundant rainfall, such as Indonesia and Thailand, irrigation needs are very low, so household water supply is the main use for groundwater.

Which areas in the United States are most dependent on groundwater?

Groundwater use is highest in parts of the country with limited rainfall but high water needs, especially for irrigation purposes. Most of these areas are in the western half of the country, where annual rainfall is typically much lower than in the East and where surface water supplies cannot meet the demand for water.

In 2010, groundwater provided 25% of the total freshwater used in the United States. However, nine states depended on groundwater for at least 50% of their freshwater supply:1

Interactive map of water wells in Nebraska

The Nebraska Department of Natural Resources provides an interactive map of water wells in the state. Wells are color-coded by use, and include geothermal, injection, irrigation, domestic, monitoring, and commerical wells, plus many other types. Users can click on each well to access registration and ownership information.

Additional map layers include transportation, aerial photography, and lakes and rivers.

Click here to access the Nebraska DNR's map of water wells.

Brackish and Saline Groundwater in New Mexico

New Mexico meets its ever-growing need for water through both surface and ground-water resources. The supply of surface water is largely dependent upon precipitation, and its availability is therefore subject to periods of drought. Shallow, fresh groundwater resources supplement the state’s water needs, but many of these resources are being used far faster than they are being replenished, and are therefore finite. We know that there are deeper, largely untapped groundwater resources, but generally these are too salty to drink or to use for irrigation without treatment. Nonetheless, they provide a potential alternative source of groundwater, and are of increasing interest to the state, particularly as our evolving technologies are providing ways for us to use them.


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