Water Availability—The Connection Between Water Use and

Quality 

Water availability has become a high priority in the United 

States, in large part because competition for water is becoming more intense across the Nation. Population growth in many 

areas competes with demands for water to support irrigation and 

power production. Cities, farms, and power plants compete for 

water needed by aquatic ecosystems to support their minimum 

flow requirements. At the same time, naturally occurring and 

human-related contaminants from chemical use, land use, and 

wastewater and industrial discharge are introduced into our 

waters and diminish its quality. 

The fact that degraded quality limits the availability and 

suitability of water for critical uses is a well-known reality in 

many communities. What may be less understood, but equally 

true, is that our everyday use of water can significantly affect 

water quality, and thus its availability. Landscape features (such 

as geology, soils, and vegetation) along with water-use practices (such as ground-water withdrawals and irrigation) govern 

water availability because, together, they affect the movement 

of chemical compounds over the land and in the subsurface. 

Understanding the interactions of human activities with natural 

sources and the landscape is critical to effectively managing 

water and sustaining water availability in the future. 

ATLANTIC

OCEAN

DELAWARE BAY 

30'

74o

EXPLANATION 30'

Extent of the Kirkwood-


Cohansey aquifer system
 

Area of agricultural land on the


Bridgeton Formation outcrop
 

Pinelands 

75o 

NEW
 

JERSEY
 

Area of 

detail 

0 20 40 MILES 

0 20 40 KILOMETERS 

EXPLANATION

Kirkwood Formation outcrop 

Cohansey Sand outcrop 

Bridgeton Formation outcrop 

Agricultural land 

PUBLIC-SUPPLY WELLS 

Total radium concentration less than 

5 picocuries per liter 

Total radium concentration greater than 

5 picocuries per liter 

ALL OTHER WELLS 

Total radium concentration less than 

5 picocuries per liter 

Total radium concentration greater than 

5 picocuries per liter 

0 5 10 MILES 

0 5 10 KILOMETERS 

Understanding the Connection Through Examples 

This document highlights several case examples and presents selected recommendations for increasing our understanding 

of the connections between water use and management, water 

quality, and availability. 

Agricultural Practices Enhance Ground-Water 

Concentrations of Naturally Occurring Radium in 

Southern New Jersey 

Concentrations of total radium in the Kirkwood-Cohansey aquifer system underlying southern New Jersey exceeded 

the U.S. Environmental Protection Agency (USEPA) drinking-water standard of 5 picocuries per liter in water from about 

one-third of the 170 wells sampled by the U.S. Geological 

Survey (USGS) in the late 1990s (Szabo and DePaul, 1998). 

(This standard, also referred to as the Maximum Contaminant 

Level, or MCL, is USEPA’s maximum permissible level of a 

contaminant in water delivered to any user of a public water 

system.) Some of the highest concentrations of total radium 

Radium concentrations commonly exceeded the U.S. Environmental Protection Agency drinking-water standard (5 picocuries per liter) 

in or near agricultural areas overlying the Bridgeton Formation in southern New Jersey, in large part because liming and fertilizers have 

modified natural ground-water chemistry and increased the mobility of radium within the aquifer (Szabo and DePaul, 1998). 

U.S. Department of the Interior Fact Sheet 2008–3015 

Printed on recycled paper U.S. Geological Survey March 2008 
 

 

 

 

 

 

 

 

 

were in or near agricultural areas overlying the Bridgeton 

Formation where the ground water is acidic (pH less than 5). 

USGS findings suggest that agricultural practices, including use 

of lime and fertilizers, have modified ground-water chemistry 

and created an environment that increased the mobility of the 

naturally occurring radium within the aquifer. The MCL was 

exceeded more frequently in water from domestic wells than in 

water from public-supply wells sampled in the USGS study. The 

results may differ in large part because public-supply wells typically are distant from agricultural areas, tap relatively deep parts 

of the aquifer not as affected by activities on the land surface, 

and draw water from relatively large areas associated with large 

pumping volumes. 

Naturally occurring chemicals that are considered contaminants in domestic well waters are not limited to New Jersey. 

For example, USGS studies show that concentrations of radon 

exceeded the proposed USEPA alternative MCL of 4,000 picocuries per liter in water from about one third of the domestic 

wells sampled in crystalline aquifers throughout New England 

(Ayotte and others, 2007). Arsenic, also naturally occurring, is 

elevated in water from domestic wells in selected areas across 

the United States, exceeding the MCL of 10 parts per billion 

in about 7 percent of wells sampled by the USGS. Some of the 

highest concentrations—a maximum of about 240 parts per 

billion—were found in the High Plains aquifers in Nebraska 

and Texas and in the Basin and Range aquifers in Arizona 

(McMahon and others, 2007; L.A. Desimone, U.S. Geological 

Survey, written commun., 2008). Concentrations differed across 

the country, owing to a combination of natural features, such as 

the presence of pyrite and other sulfide minerals, iron oxides, 

thermal water, and evapotranspiration (Welch and others, 2001). 

Ground-Water Development Mobilizes Naturally 

Occurring Uranium to Public-Supply Wells in the 

San Joaquin Valley, California 

In the past 10 years, elevated concentrations of dissolved 

uranium exceeding the USEPA MCL of 30 parts per billion 

have necessitated the removal of at least 14 public-supply wells 

from service in the eastern San Joaquin Valley of California. 

Uranium occurs naturally in soils and aquifer sediment derived 

from Sierra Nevada granitic rocks. USGS studies show that 

agricultural and urban development has increased pumping, as 

well as modified natural ground-water chemistry by enriching 

the ground water with dissolved oxygen and increasing alkalinity. Together, an environment was created in the San Joaquin 

Valley that promotes the leaching of uranium from sediments 

as water recharges the land surface and moves to the aquifer 

system, ultimately affecting the deeper parts of the aquifer used 

for public supply (Jurgens and others, 2005). 

Withdrawals Enhance Saltwater Intrusion in Coastal 

Areas in the United States 

In numerous coastal areas, large drawdowns in pumping wells cause adjacent or underlying saltwater to move into 

the freshwater system and affect the salinity of water supplies. 

Examples include Los Angeles and Orange Counties in California; Jacksonville, Tampa, and Miami, Florida; and coastal counties of New York and New Jersey. For example, as pumping in 

the Old Bridge aquifer underlying Union Beach Borough, New 

Jersey, caused ground-water levels to decline below sea level, 

saline water moved landward and concentrations of chloride and 

dissolved solids increased. As a result, pumping was curtailed 

in the 1980s, and the wells were abandoned in the early 1990s, 

replaced by wells farther inland (Alley and others, 1999; 

Barlow, 2003). 

Pumping Induces Movement of Pesticides from 

Streams to Public-Supply Wells in the Midwest 

In midwestern communities, high-capacity water-supply 

wells commonly are completed in the relatively permeable, 

unconsolidated sediments called alluvial deposits adjacent to 

large streams and rivers. Pumping can affect the movement 

of water between the alluvial aquifer and streams, and chemicals that are applied to farmland and transported in runoff can 

ultimately affect the quality of ground water used for drinking. 

In the Great Miami and Little Miami River basins in southwest 

Ohio, for example, USGS studies show that at least one pesticide was detected in 60 percent of samples from public-supply 

wells (about 80 feet deep). In this case, high pumping rates, as 

well as permeable streambed sediments and aquifer materials, 

have caused stream water to move into the ground-water 

system, sometimes reaching the wells in weeks or even days 

(Rowe and others, 2004). 

Near Cedar Rapids, Iowa, pumping from public-supply 

wells has induced infiltration from the Cedar River, allowing 

contaminants to enter ground water. These contaminants often 

include pesticide breakdown products, which are forms of parent chemicals after transformation through natural processes. 

On average, nearly 85 percent of the total pesticide concentration in stream samples was composed of 10 breakdown products of agricultural herbicides, including acetochlor, alachlor, 

atrazine, cyanazine, and metolachlor. As a result, Cedar Rapids 

officials are pursuing additional research and monitoring of 

breakdown products and parent pesticide compounds in ground 

water used for city water supplies (Kalkhoff and others, 2000). 

Re-use of River Water Affects Ground-Water Quality 

Underlying Coastal Basins of Southern California 

The Santa Ana River is an example of a highly engineered 

system in which water re-use affects the movement of water 

over the land and in the subsurface, ultimately affecting the 

quality of water used for public supply. In this basin, surface 

and ground water are cycled twice before being discharged to 

the ocean. In the first cycle, tributaries exiting the San Gabriel 

and San Bernandino Mountains are diverted to ground-water 

recharge facilities in the Inland Basin, where ground water is 

later extracted for use and then discharged as treated wastewater to the Santa Ana River. In the second cycle, flow in the 

Santa Ana River is recharged to coastal aquifers. The artificially 

recharged water accounts for about three quarters of the water 

pumped from the coastal aquifer system (about 270 million gallons per day), and contributes water used for public supply for 

nearly 5 million people living in the Santa Ana Basin. 

The large-scale pumping and recharge in the coastal basins 

have accelerated the flow of ground water and increased the 
 

 

transport of man-made compounds in ground water. The presence of tritium, an indicator of ground water recharged since 

the early 1950s, was common in USGS water samples, indicating widespread replacement of older, native ground water with 

water recharged during the past 50 years. Other man-made 

compounds, including chloroform, which is a byproduct of 

water treatment for disinfection, also were widely distributed in 

the aquifer system (although remaining below USEPA drinkingwater standards). The findings indicate that highly engineered 

systems in which water is re-used and exchanged between 

surface and ground-water systems can influence water in the 

future—in this case, today’s surface water affecting tomorrow’s 

ground water (Belitz and others, 2004). 

Water managers utilize the flow of the Santa Ana River for 

recharging coastal aquifers. An inflatable rubber dam across 

the Santa Ana River impounds water to facilitate diversion into 

recharge ponds (Belitz and others, 2004). 

Natural Factors and Human Activities Affect Salinity 

in the Southwest 

USGS findings document the variability of salinity (dissolved solids) in streams throughout the Southwest—from 22 to 

13,800 milligrams per liter. A USGS study using geostatistical 

modeling shows that both natural factors and human activities 

affect the degree of salinity in streams. Specifically, land-use 

practices and irrigation associated with pasture and cultivated 

land contribute more than half (56 percent) of the salinity 

to streams, whereas natural geologic materials provide the 

remaining 44 percent. The study also shows that the amount of 

dissolved solids that is transported and reaches streams varies 

considerably throughout the area, controlled in large part by 

water-use and agricultural activities, hydrology, and geology 

(Anning and others, 2007). 

Understanding where salinity transport and accumulation 

occur is critical to identifying watersheds primarily responsible 

for delivering salts to the Colorado River and its tributaries. 

Water managers, policy makers, drinking-water suppliers, and 

scientists throughout the region are using the results of USGS 

studies to implement and evaluate various salinity-control and 

water-management strategies throughout the Colorado River 

Basin. For example, the Colorado River Basin Salinity Control 

Program, a successful cooperation among local, State, and Federal agencies, set an overall goal to cost-effectively reduce the 

amount of salinity in the Colorado River Basin. Salinity control 

projects, which involve low water-use irrigation systems and redirection of saline water from streams, have been implemented 

since the mid-1970s by the Bureau of Reclamation (BOR), U.S. 

Department of Agriculture, and the Bureau of Land Management to control salinity of water per the 1974 Colorado River 

Basin Salinity Control Act (http://www.usbr.gov/uc/progact/ 

salinity/). 

USGS findings show that salinity decreased from 1989 

through 2003 at all sites downstream from salinity-control 

projects, mostly located in the upper parts of the Colorado River 

Basin. For example, estimated annual loads of dissolved solids 

decreased by about 160,000 tons per year (or 14 percent of the 

annual load) downstream from the salinity-control unit on the 

Gunnison River. Decreases downstream from other projects 

ranged from about 4 to 11 percent of the annual loads. The continued, long-term decreases in salinity in the upper parts of the 

Colorado River Basin have resulted in salinity levels well below 

established goals at sites in or adjacent to the Lower Colorado 

River, including below Hoover and Parker Dams, and above 

Imperial Dam. On the basis of a BOR salinity damage model, 

the economic benefit of the decreases are estimated to be about 

$230M per year, in large part related to diminished damages to 

crops and crop yields (U.S. Department of the Interior, 2005). 

Recommended Actions 

The examples herein illustrate how water use and management practices, together with natural features and the landscape, 

can affect water quality, and thus the availability of water for 

critical uses. As addressed by the Subcommittee of Water Availability and Quality (SWAQ), under the National Science and 

Technology Council, strategic investments in water science and 

technology can move the Nation forward in addressing some of 

these water availability challenges (National Science and Technology Council of the Executive Office of the President, 2007). 

SWAQ, which is made up of 25 Federal agencies responsible 

for Federal water research and (or) water-resource management, 

reports on a “coordinated, multi-year plan to improve research 

to understand the processes that control water availability and 

quality, and to collect and make available the data needed 

to ensure an adequate water supply for the Nation’s future.” 

Selected recommendations include the following: 

•	 Continue to devise a national strategy, in partnership with 

State, regional, and local water agencies, for conducting a periodic inventory of the quantity and quality of the 

Nation’s water resources, water use, and water infrastructure. 

•	 Continue to develop cost-effective water monitoring technology, such as sensors and systems to measure real-time 

water volumes and water quality, and develop standards and 

protocols for effective collection, management, and communication of data. 

•	 Develop innovative technologies to use water more efficiently in the agricultural, energy, and industry sectors.
 

•	 Continue to improve understanding of water-related 

ecosystem needs by expanding monitoring, modeling, and 

research in ecosystem-based studies. 
•	 Improve hydrologic models and their applications for decision-making at watershed scales. Inherent in model refinement are improved ancillary data, such as on hydrology, 

geology, soils, climate, aquatic habitats, land-use changes, 

and chemical use. 

•	 Support long-term data collection to provide an empirical 

basis for models and research needed to predict impacts of 

land-use change, water-use change, and climate change on 

the availability of water suitable for its intended uses. 

References Cited 

Alley, W.M., Reilly, T.E., and Franke, O.L., 1999, Sustainability 

of Ground-Water Resources: U.S. Geological Survey Circular 

1186, 79 p. (http://pubs.usgs.gov/circ/circ1186/) 

Anning, D.W., Bauch, N.J., Gerner, S.J., Flynn, M.E., Hamlin, 

S.N., Moore, S.J., Schaefer, D.H., Anderholm, S.K., and 

Spangler, L.E., 2007, Dissolved Solids in Basin-Fill Aquifers 

and Streams in the Southwestern United States: U.S. Geological Survey Scientific Investigations Report 2006–5315, 

187 p. (http://pubs.usgs.gov/sir/2006/5315/) 

Ayotte, J.D., Flanagan, S.M., and Morrow, W.S., 2007, Occurrence of Uranium and 222Radon in Glacial and Bedrock Aquifers in the Northern United States, 1993–2003: U.S. Geological Survey Scientific Investigations Report 2007–5037, 85 p. 

(http://pubs.er.usgs.gov/usgspubs/sir/sir20075037) 

Barlow, P.M., 2003, Ground water in freshwater-saltwater 

environments of the Atlantic Coast: U.S. Geological Survey 

Circular 1262, 113 p. (http://pubs.er.usgs.gov/usgspubs/cir/ 

cir1262) 

Belitz, Kenneth, Hamlin, S.N., Burton, C.A., Kent, Robert, Fay, 

R.G., and Johnson, Tyler, 2004, Water Quality in the Santa 

Ana Basin, California, 1999–2004: U.S. Geological Survey 

Circular 1238, 37 p. (http://pubs.usgs.gov/circ/2004/1238/) 

Jurgens, Bryant, Burow, Karen, Brown, C.J., Dubrovsky, N.M., 

and Stollenwerk, K.G., 2005, Elevated Levels of Naturally 

Occurring Uranium in Ground Water in Modesto, California: 

Geological Society of America Abstracts with Programs, v. 

37, no. 7, p. 356. 

Kalkhoff, S.J., Barnes, K.K., Becher, K.D., Savoca, M.E., 

Schnoebelen, D.J., Sadorf, E.M., Porter, S.D., and Sullivan, 

D.J., 2000, Water Quality in the Eastern Iowa Basins, Iowa 

and Minnesota, 1996–98: U.S. Geological Survey Circular 

1210, 37 p. (http://pubs.usgs.gov/circ/circ1210/) 

McMahon, P.B., Dennehy, K.F., Bruce, B.W., Gurdak, J.J, and 

Qi, S.L., 2007, Water-Quality Assessment of the High Plains 

Aquifer, 1999–2004: U.S. Geological Survey Professional 

Paper 1749, 136 p. (http://pubs.er.usgs.gov/usgspubs/pp/ 

pp1749) 

National Science and Technology Council of the Executive 

Office of the President, 2007, A Strategy for Federal Science 

and Technology to Support Water Availability and Quality 

in the United States, Report by the Subcommittee of Water 

Availability and Quality in the United States, September 

.2007, 35 p. (http://www.ostp.gov/galleries/NSTC/Fed%20ST 

%20Strategy%20for%20Water%209-07%20FINAL.pdf) 

Rowe, G.L., Reutter, D.C., Runkle, D.L., Hambrook, J.A., 

Janosy, S.D., and Hwang, L.H., 2004, Water Quality in the 

Great and Little Miami River Basins, Ohio and Indiana, 

1999–2001: U.S. Geological Survey Circular 1229, 40 p. 

(http://pubs.er.usgs.gov/usgspubs/cir/cir1229) 

Szabo, Zoltan, and DePaul, Vincent, 1998, Radium-226 and 

Radium-228 in Shallow Ground Water, Southern New Jersey: 

U.S. Geological Survey Fact Sheet 062–98, 6 p. (http://pubs. 

er.usgs.gov/usgspubs/fs/fs06298) 

U.S. Department of the Interior, 2005, Quality of Water—Colorado River Basin Progress Report No. 22: U.S. Department of 

the Interior, 69 p. (accessed from http://www.usbr.gov/uc/ 

progact/salinity/) 

Welch, Alan, Ryker, Sarah, Helsel, Dennis, and Hamilton, P.A., 

2001, Arsenic in Ground Water of the United States—An 

Overview: Water Well Journal, February 2001, p. 30–33. 

By Robert M. Hirsch, Pixie A. Hamilton, Timothy L. 

Miller, and Donna N. Myers 

Contacts 

Robert Hirsch 

USGS Associate Director, Water 

(703) 648-5215 

rhirsch@usgs.gov 

Timothy Miller 

Chief, Office of Water Quality 

(703) 648-6868

 tlmiller@usgs.gov 

Donna Myers 

Chief, National Water-Quality Assessment (NAWQA) Program 

(703) 648-5012 

dnmyers@usgs.gov 

Pixie Hamilton 

Hydrologist, NAWQA 

(804) 261-2602 

pahamilt@usgs.gov 

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