Fractured-Rock Aquifers: Understanding an Increasingly Important Source of Water
Fractured-rock aquifers in the United States provide water for domestic use, locations for isolating hazardous and toxic waste, and sites for foundations and infrastructure.
Ground water is one of the Nations most important natural resources. It provides drinking water to communities, supports industry and agriculture, and sustains streams and wetlands. A long record of contributions exists in understanding ground-water movement in sand and gravel aquifers; historically, these aquifers were easily accessible and the first to be investigated. With increased demand for water, communities are looking to fractured-rock aquifers, where water moves through fractures in the rock. Frac-tures, however, may not always convey or store large quantities of water. Understanding ground-water flow through fractured-rock aquifers is an area of ground-water research that will have increasing importance to our Nation over the coming years.
Many areas of the United States rely on fractured-rock aquifers for water supply. In addition, areas experiencing population growth in the Northeast, Southeast, and mountainous regions of the West are likely to rely heavily on water supplies from fractured-rock aquifers. Finding water for thirsty communities, however, is not the only societal issue requiring an understanding of ground-water flow in fractured rock. Land-use practices affect water quality in fractured-rock aquifers, particularly where ground water flows rapidly through fractures. Fractured rock aquifers also are viewed as potential repositories for radioactive and other types of waste, where it is desirable for the ground water to be inaccessible or move at a very slow rate.
Complexity of Fractured Rock
USGS Research in Fractured Rock
The USGS conducts research to develop field techniques and
interpretive methods for characterizing fluid movement and chemical migration
in fractured-rock aquifers to answer such questions. USGS research focuses
on characterizing ground-water flow in fractured-rock aquifers over distances
from meters to kilometers. Research is conducted at well-instrumented
field research sites, such as the Mirror Lake water-shed in central New
Hampshire, or on actual field problems with resource managers and regulators.
Ground-water resource managers and geological and structural engineers
are now applying the results of this research in fractured-rock aquifers
throughout the United States.
With the experience in characterizing ground-water flow in fractured-rock aquifers, the USGS is now addressing other issues of societal importance in fractured-rock aquifers, which include processes affecting bacterial activity, and the transport of colloids and pathogens.
- A. M. Shapiro
For More Information
USGS, National Research Program, Transport Phenomena in Fractured Rock: http://water.usgs.gov/nrp/proj.bib/shapiro.html
USGS, National Research Program, Hydrology of Fractured Rocks: http://water.usgs.gov/nrp/proj.bib/hsieh.html
Fluid Flow and Solute Transport in Fractured Rock, Mirror Lake, New Hampshire: http://toxics.usgs.gov/sites/mirror_page.html
Natural Attenuation of Chlorinated Solvents in Fractured Rocks, Naval Air Warfare Center Research Site, Trenton, New Jersey: http://toxics.usgs.gov/sites/nawc_page.html
USGS, Ground-Water Resources Program: http://water.usgs.gov/ogw/GWRP.html
USGS, Toxic Substances Hydrology Program: http://toxics.usgs.gov
USGS, Office of Ground Water, Branch of Geophysics: http://water.usgs.gov/ogw/bgas