Library Index :: The Complete Guide to Water :: Water Use - Freshwater Availability, How Water Is Supplied, Types Of Water Use In The United States, Right To Water Use

Water Use - Types Of Water Use In The United States

For reporting purposes, water use in the United States is classified as in-stream or off-stream. In in-stream use, the water is used at its source—usually a river or stream—and the vast majority of the water is returned immediately to the source. Little or no water is actually consumed. Examples are hydroelectric plants where water flows through the generators and goes right back into the river it came from ("return flow") and water-powered mills used to grind corn.

In off-stream use, the water is diverted from a surface source or withdrawn from a groundwater source and conveyed to the place where it is actually used. In 2000 off-stream water use nationwide was 408 billion gallons per day. Table 2.1 and Figure 2.2 show total water withdrawals by source and state for the year 2000. At 51.2 billion gallons per day, California used more water than any other state by a large margin.

In many cases, off-stream use results in substantial consumptive use of water. Consumptive use may be quantitative or qualitative. Quantitative consumption occurs when part of the water withdrawn is evaporated, transpired by plants, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment, so that the quantity returned to the source is substantially less than the quantity of water withdrawn. An example of consumptive use is spray irrigation, where less than 60% of the water used to irrigate crops is returned to the source. Qualitative consumption occurs when the quality of the water is substantially altered so that it is no longer acceptable for use by downstream users, but the quantity remains substantially unchanged. An example would be discharge of industrial wastes to a body of water that renders the water unfit for drinking water. Many water withdrawals result in both quantitative and qualitative consumption.

Off-Stream Use

Water use in the United States is monitored and reported by the U.S. Geological Survey (USGS) in its Estimated Use of Water in the United States, published at five-year intervals since 1950. The 2000 report (the latest data available, published in 2004) found that an estimated 408 billion gallons of water per day (freshwater and saline water) were withdrawn from surface or ground-water sources for off-stream use in the United States. This was slightly more than the 402 billion gallons withdrawn per day in 1995. Of the water involved in off-stream use, 85% is freshwater. Per capita use for all off-stream uses in 1995 was 1,430 gallons per day of fresh and saline water combined (1,210 gallons per day of freshwater).

Off-stream use is further divided into eight categories:

  • Public supply
  • Domestic
  • Irrigation
  • Livestock
  • Aquaculture
  • Industrial
  • Mining
  • Thermoelectric power

Table 2.2 shows the total amounts of water withdrawn for each category.

TABLE 2.1
Total water withdrawals by state, 2000
[Figures may not sum to totals because of independent rounding]
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Table 1. Total Water Withdrawals by Source and State, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/(accessed March 30, 2005)

Withdrawals (in million gallons per day) Withdrawals (in thousand acre-feet per year)
By source and type
State Population (in thousands) Ground water Surface water Total Total
Fresh Saline Total Fresh Saline Total Fresh Saline Total Fresh Saline Total
Alabama 4,450 440 0 440 9,550 0 9,550 9,990 0 9,990 11,200 0 11,200
Alaska 627 50.2 90.4 141 111 53.4 164 161 144 305 181 161 342
Arizona 5,130 3,420 8.17 3,430 3,300 0 3,300 6,720 8.17 6,730 7,530 9.16 7,540
Arkansas 2,670 6,920 .08 6,920 3,950 0 3,950 10,900 .08 10,900 12,200 .09 12,200
California 33,900 15,200 152 15,400 23,200 12,600 35,800 38,400 12,800 51,200 43,100 14,300 57,400
Colorado 4,300 2,320 0 2,320 10,300 0 10,300 12,600 0 12,600 14,200 0 14,200
Connecticut 3,410 143 0 143 565 3,440 4,010 708 3,440 4,150 794 3,860 4,650
Delaware 784 115 0 115 466 741 1,210 582 741 1,320 652 831 1,480
District of Columbia 572 0 0 0 9.87 0 9.87 9.87 0 9.87 11.1 0 11.1
Florida 16,000 5,020 0 5,020 3,110 12,000 15,100 8,140 12,000 20,100 9,120 13,400 22,500
Georgia 8,190 1,450 0 1,450 4,960 91.7 5,060 6,410 91.7 6,500 7,190 103 7,290
Hawaii 1,210 433 .85 434 208 0 208 640 .85 641 718 .95 719
Idaho 1,290 4,140 0 4,140 15,300 0 15,300 19,500 0 19,500 21,800 0 21,800
Illinois 12,400 813 0 813 12,900 0 12,900 13,700 0 13,700 15,400 0 15,400
Indiana 6,080 656 0 656 9,460 0 9,460 10,100 0 10,100 11,300 0 11,300
Iowa 2,930 679 0 679 2,680 0 2,680 3,360 0 3,360 3,770 0 3,770
Kansas 2,690 3,790 0 3,790 2,820 0 2,820 6,610 0 6,610 7,410 0 7,410
Kentucky 4,040 189 0 189 3,970 0 3,970 4,160 0 4,160 4,660 0 4,660
Louisiana 4,470 1,630 0 1,630 8,730 0 8,730 10,400 0 10,400 11,600 0 11,600
Maine 1,270 80.8 0 80.8 423 295 718 504 295 799 565 330 895
Maryland 5,300 225 0 225 1,200 6,490 7,690 1,430 6,490 7,910 1,600 7,270 8,870
Massachusetts 6,350 269 0 269 783 3,610 4,390 1,050 3,610 4,660 1,180 4,050 5,220
Michigan 9,940 734 0 734 9,260 0 9,260 10,000 0 10,000 11,200 0 11,200
Minnesota 4,920 720 0 720 3,150 0 3,150 3,870 0 3,870 4,340 0 4,340
Mississippi 2,840 2,180 0 2,180 632 148 781 2,810 148 2,960 3,150 166 3,320
Missouri 5,600 1,780 0 1,780 6,450 0 6,450 8,230 0 8,230 9,220 0 9,220
Montana 902 188 0 188 8,100 0 8,100 8,290 0 8,290 9,300 0 9,300
Nebraska 1,710 7,860 4.55 7,860 4,390 0 4,390 12,200 4.55 12,300 13,700 5.10 13,700
Nevada 2,000 757 0 757 2,050 0 2,050 2,810 0 2,810 3,140 0 3,140
New Hampshire 1,240 85.2 0 85.2 362 761 1,120 447 761 1,210 501 854 1,350
New Jersey 8,410 584 0 584 1,590 3,390 4,980 2,170 3,390 5,560 2,430 3,800 6,230
New Mexico 1,820 1,540 0 1,540 1,710 0 1,710 3,260 0 3,260 3,650 0 3,650
New York 19,000 893 0 893 6,190 5,010 11,200 7,080 5,010 12,100 7,940 5,610 13,600
North Carolina 8,050 580 0 580 9,150 1,620 10,800 9,730 1,620 11,400 10,900 1,810 12,700
North Dakota 642 123 0 123 1,020 0 1,020 1,140 0 1,140 1,280 0 1,280
Ohio 11,400 878 0 878 10,300 0 10,300 11,100 0 11,100 12,500 0 12,500
Oklahoma 3,450 771 256 1,030 990 0 990 1,760 256 2,020 1,970 287 2,260
Oregon 3,420 993 0 993 5,940 0 5,940 6,930 0 6,930 7,770 0 7,770
Pennsylvania 12,300 666 0 666 9,290 0 9,290 9,950 0 9,950 11,200 0 11,200
Rhode Island 1,050 28.6 0 28.6 110 290 400 138 290 429 155 326 481
South Carolina 4,010 330 0 330 6,840 0 6,840 7,170 0 7,170 8,040 0 8,040
South Dakota 755 222 0 222 306 0 306 528 0 528 592 0 592
Tennessee 5,690 417 0 417 10,400 0 10,400 10,800 0 10,800 12,100 0 12,100
Texas 20,900 8,470 504 8,970 16,300 4,350 20,700 24,800 4,850 29,600 27,800 5,440 33,200
Utah 2,230 1,020 26.5 1,050 3,740 177 3,920 4,760 203 4,970 5,340 228 5,570
Vermont 609 43.2 0 43.2 404 0 404 447 0 447 501 0 501
Virginia 7,080 314 0 314 4,880 3,640 8,520 5,200 3,640 8,830 5,830 4,080 9,900
Washington 5,890 1,470 0 1,470 3,800 39.9 3,840 5,270 39.9 5,310 5,910 44.7 5,960
West Virginia 1,810 90.9 0 90.9 5,060 0 5,060 5,150 0 5,150 5,770 0 5,770
Wisconsin 5,360 813 0 813 6,780 0 6,780 7,590 0 7,590 8,510 0 8,510
Wyoming 494 541 222 763 4,400 0 4,400 4,940 222 5,170 5,540 248 5,790
Puerto Rico 3,810 137 0 137 483 2,190 2,670 620 2,190 2,810 695 2,460 3,150
U.S. Virgin Islands 109 1.03 0 1.03 10.6 136 147 11.6 136 148 13.0 153 166
    Total 285,000 83,300 1,260 84,500 262,000 61,000 323,000 345,000 62,300 408,000 387,000 69,800 457,000

PUBLIC SUPPLY.

Public supply refers to water withdrawn by public and private water suppliers (utility companies) and delivered to users for domestic, commercial, industrial, and thermoelectric power uses. The latest data available from the U.S. Geological Survey show that public suppliers serviced about 242 million people in 2000 (about 85% of the total population of the United States at that time). This represented an 8% increase over FIGURE 2.2
State-by-state map of total water use, 2000
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Figure 2. Total, Surface-Water, and Ground-Water Withdrawals, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005) the number of people supplied with water by public suppliers in 1995, just five years earlier. Of the 43.3 billion gallons per day supplied for public use, more than half was for domestic use. Other uses were commercial, public (fire fighting, street washing, municipal parks and swimming pools, government office buildings), industrial, and thermoelectric power production. Public suppliers withdrew 63% of their water from surface sources and 37% from groundwater sources. Table 2.3 and Figure 2.3 show the latest data available on the total amount of water withdrawn for public supply in 2000 by state and the amount of surface water and groundwater withdrawn.

According to Estimated Use of Water in the United States in 2000, the public water systems of the United States provided, on average, 179 gallons of water per person per day in 2000, the same as for 1995 and down from 184 gallons per person per day reported for 1990. This was the first time public supply per capita use had declined since 1950. The five most populous states—California, Florida, Illinois, New York, and Texas—accounted for 39.5% of U.S. public-supply withdrawals.

DOMESTIC USE.

Domestic water use includes water for typical household purposes, such as drinking; food preparation; bathing; washing clothes, dishes, and cars; flushing toilets; and watering lawns and gardens. Although a person needs less than two quarts a day (from liquid and solid foods) to survive, actual daily household use (indoor and outdoor) is much higher.

The American Water Works Association Research Foundation (AWWARF) studied residential end-uses of water in fourteen North American cities from 1996 to 1999. Their report, Residential End Uses of Water Study, concluded that flushing the toilet used the most water TABLE 2.2
Total water withdrawals by usage category, 2000
[Figures may not sum to totals because of independent rounding. All values are in million gallons per day.]
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Table 2. Total Water Withdrawals by Water-Use Category, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005)

Public supply Domestic Irrigation Livestock Aquaculture Industrial Mining Thermoelectric power Total
State Fresh Fresh Fresh Fresh Fresh Fresh Saline Fresh Saline Fresh Saline Fresh Saline Total
Alabama 834 78.9 43.1 — 10.4 833 0 — — 8,190 0 9,990 0 9,990
Alaska 80.0 11.2 1.01 — — 8.12 3.86 27.4 140 33.6 0 161 144 305
Arizona 1,080 28.9 5,400 — — 19.8 0 85.7 8.17 100 0 6,720 8.17 6,730
Arkansas 421 28.5 7,910 — 198 134 .08 2.78 0 2,180 0 10,900 .08 10,900
California 6,120 286 30,500 409 537 188 13.6 23.7 153 352 12,600 38,400 12,800 51,200
Colorado 899 66.8 11,400 — — 120 0 — — 138 0 12,600 0 12,600
Connecticut 424 56.2 30.4 — — 10.7 0 — — 187 3,440 708 3,440 4,150
Delaware 94.9 13.3 43.5 3.92 .07 59.4 3.25 — — 366 738 582 741 1,320
District of Columbia 0 0 .18 — — 0 0 — — 9.69 0 9.87 0 9.87
Florida 2,440 199 4,290 32.5 8.02 291 1.18 217 0 658 12,000 8,140 12,000 20,100
Georgia 1,250 110 1,140 19.4 15.4 622 30 9.80 0 3,250 61.7 6,410 91.7 6,500
Hawaii 250 12.0 364 — — 14.5 .85 — — 0 0 640 .85 641
Idaho 244 85.2 17,100 34.9 1,970 55.5 0 — — 0 0 19,500 0 19,500
Illinois 1,760 135 154 37.6 — 391 0 — — 11,300 0 13,700 0 13,700
Indiana 670 122 101 41.9 — 2,400 0 82.5 0 6,700 0 10,100 0 10,100
Iowa 383 33.2 21.5 109 — 237 0 32.8 0 2,540 0 3,360 0 3,360
Kansas 416 21.6 3,710 111 5.60 53.3 0 31.4 0 2,260 0 6,610 0 6,610
Kentucky 525 27.5 29.3 — — 317 0 — — 3,260 0 4,160 0 4,160
Louisiana 753 41.2 1,020 7.34 243 2,680 0 — — 5,610 0 10,400 0 10,400
Maine 102 35.7 5.84 — — 247 0 — — 113 295 504 295 799
Maryland 824 77.1 42.4 10.4 19.6 65.8 227 8.31 .02 379 6,260 1,430 6,490 7,910
Massachusetts 739 42.2 126 — — 36.8 0 — — 108 3,610 1,050 3,610 4,660
Michigan 1,140 239 201 11.3 — 698 0 — — 7,710 0 10,000 0 10,000
Minnesota 500 80.8 227 52.8 — 154 0 588 0 2,270 0 3,870 0 3,870
Mississippi 359 69.3 1,410 — 371 242 0 — — 362 148 2,810 148 2,960
Missouri 872 53.6 1,430 72.4 83.3 62.7 0 16.9 0 5,640 0 8,230 0 8,230
Montana 149 18.6 7,950 — — 61.3 0 — — 110 0 8,290 0 8,290
Nebraska 330 48.4 8,790 93.4 — 38.1 0 128 4.55 2,820 0 12,200 4.55 12,300
Nevada 629 22.4 2,110 — — 10.3 0 — — 36.7 0 2,810 0 2,810
New Hampshire 97.1 41.0 4.75 — 16.3 44.9 0 6.8 0 236 761 447 761 1,210
New Jersey 1,050 79.7 140 1.68 6.46 132 0 110 0 650 3,390 2,170 3,390 5,560
New Mexico 296 31.4 2,860 — — 10.5 0 — — 56.4 0 3,260 0 3,260
New York 2,570 142 35.5 — — 297 0 — — 4,040 5,010 7,080 5,010 12,100
North Carolina 945 189 287 121 7.88 293 0 36.4 0 7,850 1,620 9,730 1,620 11,400
North Dakota 63.6 11.9 145 — — 17.6 0 — — 902 0 1,140 0 1,140
Ohio 1,470 134 31.7 25.3 1.36 807 0 88.5 0 8,590 0 11,100 0 11,100
Oklahoma 675 25.5 718 151 16.4 25.9 0 2.48 256 146 0 1,760 256 2,020
Oregon 566 76.2 6,080 — — 195 0 — — 15.3 0 6,930 0 6,930
Pennsylvania 1,460 132 13.9 — — 1,190 0 182 0 6,980 0 9,950 0 9,950
Rhode Island 119 8.99 3.45 — — 4.28 0 — — 2.40 290 138 290 429
South Carolina 566 63.5 267 — — 565 0 — — 5,710 0 7,170 0 7,170
South Dakota 93.3 9.53 373 42.0 — 5.12 0 — — 5.24 0 528 0 528
Tennessee 890 32.6 22.4 — — 842 0 — — 9,040 0 10,800 0 10,800
Texas 4,230 131 8,630 308 — 1,450 907 220 504 9,820 3,440 24,800 4,850 29,600
Utah 638 16.1 3,860 — 116 42.7 5.08 26.3 198 62.2 0 4,760 203 4,970
Vermont 60.1 21.0 3.78 — — 6.91 0 — — 355 0 447 0 447
Virginia 720 133 26.4 — — 470 53.3 — — 3,850 3,580 5,200 3,640 8,830
Washington 1,020 125 3,040 — — 577 39.9 — — 519 0 5,270 39.9 5,310
West Virginia 190 40.4 .04 — — 968 0 — — 3,950 0 5,150 0 5,150
Wisconsin 623 96.3 196 66.3 70.2 447 0 — — 6,090 0 7,590 0 7,590
Wyoming 107 6.57 4,500 — — 5.78 0 79.5 222 243 0 4,940 222 5,170
Puerto Rico 513 .88 94.5 — — 11.2 0 — — 0 2,190 620 2,190 2,810
U.S. Virgin Islands 6.09 1.69 .50 — — 3.34 0 — — 0 136 11.6 136 148
    Total 43,300 3,590 137,000 1,760 3,700 18,500 1,280 2,010 1,490 136,000 59,500 345,000 62,300 408,000

(20.1 gallons per person per day) of all indoor household water uses in homes not equipped with water-efficient fixtures. Laundering clothes ranked second in water use (15 gallons per person per day), and taking showers (13.3 gallons per person per day) ranked third. Outdoor household water use for such activities as filling swimming pools, watering lawns, and washing cars accounts for 50% to 70% of total household water usage, according to a 1999 Environmental Protection Agency (EPA) fact sheet, Water Facts.

TABLE 2.3
Public supply water withdrawals, 2000 [Figures may not sum to totals because of independent rounding]
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Table 5. Public Supply Water Withdrawals, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005)

Population (in thousands) Withdrawals (in million gallons per day) Withdrawals (in thousand acre-feet per year)
Served by public supply By source By source
State Total Population Population (in percent) Ground water Surface water Total Ground water Surface water Total
Alabama 4,450 3,580 80 281 553 834 315 620 935
Alaska 627 421 67 29.3 50.7 80.0 32.9 56.9 89.7
Arizona 5,130 4,870 95 469 613 1,080 526 688 1,210
Arkansas 2,670 2,320 87 132 289 421 148 324 472
California 33,900 30,100 89 2,800 3,320 6,120 3,140 3,730 6,860
Colorado 4,300 3,750 87 53.7 846 899 60.2 948 1,010
Connecticut 3,410 2,660 78 66.0 358 424 74.0 402 476
Delaware 784 617 79 45.0 49.8 94.9 50.5 55.9 106
District of Columbia 572 572 100 0 0 0 0 0 0
Florida 16,000 14,000 88 2,200 237 2,440 2,470 266 2,730
Georgia 8,190 6,730 82 278 968 1,250 311 1,090 1,400
Hawaii 1,210 1,140 94 243 7.60 250 272 8.52 281
Idaho 1,290 928 72 219 25.3 244 245 28.3 274
Illinois 12,400 10,900 88 353 1,410 1,760 396 1,580 1,970
Indiana 6,080 4,480 74 345 326 670 386 365 751
Iowa 2,930 2,410 83 303 79.8 383 340 89.5 429
Kansas 2,690 2,500 93 172 244 416 193 273 466
Kentucky 4,040 3,490 86 71.0 455 525 79.5 510 589
Louisiana 4,470 3,950 88 349 404 753 392 453 844
Maine 1,270 726 57 29.6 72.5 102 33.2 81.3 115
Maryland 5,300 4,360 82 84.6 740 824 94.8 829 924
Massachusetts 6,350 5,880 93 197 542 739 220 608 828
Michigan 9,940 7,170 72 247 896 1,140 277 1,000 1,280
Minnesota 4,920 3,770 77 329 171 500 369 192 561
Mississippi 2,840 2,190 77 319 40.4 359 357 45.3 402
Missouri 5,600 4,770 85 278 594 872 311 666 978
Montana 902 664 74 56.1 92.4 149 62.9 104 167
Nebraska 1,710 1,390 81 266 63.8 330 299 71.6 370
Nevada 2,000 1,870 94 151 478 629 169 536 705
New Hampshire 1,240 756 61 33.0 64.1 97.1 37.0 71.9 109
New Jersey 8,410 7,460 89 400 650 1,050 449 729 1,180
New Mexico 1,820 1,460 80 262 33.8 296 294 37.9 332
New York 19,000 17,100 90 583 1,980 2,570 653 2,220 2,880
North Carolina 8,050 5,350 66 166 779 945 186 873 1,060
North Dakota 642 493 77 32.4 31.2 63.6 36.3 35.0 71.3
Ohio 11,400 9,570 84 500 966 1,470 560 1,080 1,640
Oklahoma 3,450 3,150 91 113 562 675 127 631 757
Oregon 3,420 2,730 80 118 447 566 133 501 634
Pennsylvania 12,300 10,100 82 212 1,250 1,460 237 1,400 1,640
Rhode Island 1,050 922 88 16.9 102 119 19.0 115 134
South Carolina 4,010 3,160 79 105 462 566 117 517 635
South Dakota 755 625 83 54.2 39.1 93.3 60.7 43.9 105
Tennessee 5,690 5,240 92 321 569 890 360 638 997
Texas 20,900 19,700 94 1,260 2,970 4,230 1,420 3,330 4,740
Utah 2,230 2,180 97 364 274 638 408 307 715
Vermont 609 362 59 19.5 40.6 60.1 21.8 45.6 67.4
Virginia 7,080 5,310 75 70.7 650 720 79.3 728 808
Washington 5,890 4,900 83 464 552 1,020 520 619 1,140
West Virginia 1,810 1,300 72 41.6 149 190 46.6 167 213
Wisconsin 5,360 3,620 67 330 293 623 370 329 699
Wyoming 494 406 82 57.2 49.4 107 64.1 55.3 119
Puerto Rico 3,810 3,800 100 88.5 425 513 99.2 476 576
U.S. Virgin Islands 109 53.4 49 .52 5.57 6.09 .58 6.24 6.83
    Total 285,000 242,000 85 16,000 27,300 43,300 17,900 30,600 48,500

In 1992 Congress passed the Water Efficiency Act. This legislation established uniform national standards for manufacture of water-efficient plumbing fixtures, such as low-flow toilets and showers. The purpose was to promote water conservation by residential and commercial users. Since that time, many water suppliers have sponsored programs offering rebates on water bills and other incentives to encourage the use of these devices to reduce water use.

FIGURE 2.3
Public-supply withdrawals, by source and state, 2000

AQUACULTURE.

Aquaculture is the practice of raising animals that live in water—such as finfish and shellfish—for food, restoration, conservation, or sport. Aquaculture was a new category for the 2000 report. It combines the fish farming activities of the former livestock subcategory "animal specialties" and the fish hatchery activities of the commercial category that were reported previously. Aquaculture use accounted for 3.7 billion gallons per day of water use nationally in 2000. Surface water was the source of 71% of this total. Idaho alone accounted for more than half of the aquaculture water use reported. (See Table 2.4.)

IRRIGATION.

The word "irrigation" usually brings to mind arid or semiarid deserts transformed into lush green fields of crops by the turn of a handle, bringing life and FIGURE 2.3
Public-supply withdrawals, by source and state, 2000 [CONTINUED]
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Figure 5. Public-Supply Withdrawals by Source and State, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005) prosperity where before there had been only sagebrush and cactus. To some extent this is true. Many parts of the American West and Midwest do not average enough yearly rainfall to sustain the crops that are grown there; the cultivation of those crops is made possible only with the water supplied by irrigation. Irrigation is also used to supplement rainfall in areas with adequate water supplies in order to increase the number of plantings per year, improve yield, and reduce the risk of crop failure during drought years.

According to the 2000 USGS report, irrigation accounted for 34% (137,000 mgd, or million gallons per day) of freshwater withdrawals for all off-stream categories in 2000. (See Table 2.5.) Approximately 58% of withdrawals that year were from surface water sources, and the other 42% from groundwater sources. In 2000 withdrawals of freshwater for irrigation purposes dropped to 481 gallons per day per capita, compared with the 1995 per day per capita figure of 553 gallons.

The quantity of freshwater used for irrigation varies greatly from region to region. Irrigation is by far the largest water use category in the West. California alone used 22% of all irrigation water in 2000. Total withdrawals for irrigation and acres irrigated by state are shown in Figure 2.4 and Table 2.6.

Irrigation has the highest consumptive use of any of the eight categories of off-stream water use. In many irrigated areas, about 75% to 85% of the irrigation water is lost to evaporation, transpiration, or retained in the crops. The remaining 15% to 25% either infiltrates through the soil to recharge ground-water or is returned to nearby surface water through the drainage system. Average quantities of water applied range from several inches to more than twenty inches per year, depending on local conditions.

Significant changes in water quality can be caused by irrigation. The water lost in evapotranspiration is relatively pure because chemicals are left behind to precipitate as salts and to accumulate in the soil. The salts continue to accumulate as irrigation continues. In many areas, this causes the concentration of dissolved solids in the irrigation return flows to be higher than in the original irrigation water. Excessive salts can interfere with crop growth because plants are not able to filter out the salt from the water that they take up and need. In some cases, excessive salt from salt-laden water has left the soil unable to grow crops. To stop excessive buildup of salts in the soil, extra irrigation water is required to flush out the salts and transport them into the groundwater. In locations where these dissolved solids reach high concentrations, the artificial recharge from irrigation return flow can result in degradation of the quality of groundwater and the surface water to which the groundwater discharges.

TABLE 2.4
Aquaculture water withdrawals, 2000
[Figures may not sum to totals because of independent rounding]
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Table 9. Aquaculture Water Withdrawals, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005),http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005)

Withdrawals (in million gallons per day) Withdrawals (in thousand acre-feet per year)
By source By source
State Ground water Surface water Total Ground water Surface water Total
Alabama 8.93 1.44 10.4 10.0 1.61 11.6
Alaska — — — — — —
Arizona — — — — — —
Arkansas 187 10.4 198 210 11.6 222
California 158 380 537 177 426 603
Colorado — — — — — —
Connecticut — — — — — —
Delaware .07 0 .07 .08 0.08
District of Columbia — — — — — —
Florida 7.81 .21 8.02 8.76 .24 8.99
Georgia 7.70 7.72 15.4 8.63 8.65 17.3
Hawaii — — — — — —
Idaho 51.5 1,920 1,970 57.7 2,150 2,210
Illinois — — — — — —
Indiana — — — — — —
Iowa — — — — — —
Kansas 3.33 2.27 5.60 3.73 2.54 6.28
Kentucky — — — — — —
Louisiana 128 115 243 144 129 273
Maine— — — — — —
Maryland 4.81 14.8 19.6 5.39 16.6 22.0
Massachusetts — — — — — —
Michigan — — — — — —
Minnesota— — — — — —
Mississippi 321 49.8 371 360 55.9 416
Missouri 2.01 81.3 83.3 2.25 91.2 93.4
Montana — — — — — —
Nebraska — — — — — —
Nevada — — — — — —
New Hampshire 3.12 13.1 16.3 3.50 14.7 18.2
New Jersey 6.46 0 6.46 7.24 0 7.24
New Mexico — — — — — —
New York — — — — — —
North Carolina 7.88 0 7.88 8.83 0 8.83
North Dakota — — — — — —
Ohio 1.36 0 1.36 1.52 0 1.52
Oklahoma .29 16.1 16.4 .33 18.1 18.4
Oregon — — — — — —
Pennsylvania— — — — — —
Rhode Island — — — — — —
South Carolina — — — — — —
South Dakota — — — — — —
Tennessee — — — — — —
Texas — — — — — —
Utah 116 0 116 130 0 130
Vermont — — — — — —
Virginia — — — — — —
Washington — — — — — —
West Virginia — — — — — —
Wisconsin 39.8 30.4 70.2 44.6 34.1 78.7
Wyoming — — — — — —
Puerto Rico — — — — — —
U.S. Virgin Islands — — — — — —
    Total 1,060 2,640 3,700 1,180 2,960 4,150

LIVESTOCK.

Livestock water use includes four-legged stock watering, dairy and feedlot operations, and other on-farm needs. According to the most recent USGS report, 1,760 mgd of water were used for livestock in 2000. Total withdrawals for livestock increased slightly between 1995 and 2000 for the twenty-two states that reported data for both years. However, withdrawals actually increased only in eight of the twenty-two reporting TABLE 2.5
Total water use by usage catdgory, 2000
SOURCE: Adapted from Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Figure 1. Total Water Withdrawals by Category, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005)

Category Percent
Public supply 11
Irrigation 34
Aquaculture <1
Mining <1
Domestic <1
Livestock <1
Industrial 5
Thermoelectric power 48

states. California, Texas, and Oklahoma combined accounted for almost half the U.S. total livestock water use in 2000, and nearly two-thirds of the surface water used. (See Table 2.7.)

INDUSTRIAL.

Even those industries that do not use water directly in their products may use substantial quantities of water during operations. Water for industrial use is commonly divided into four categories: (1) cooling water, (2) process water, (3) boiler feed water, and (4) sanitary and service water (for personal use by employees, for cleaning plants and equipment, and for the operation of valves and other equipment). Industries that use the most water include steel, chemical and allied products, paper and related products, and petroleum refining.

Water supplied for industrial use in 2000 totaled 19.7 billion mgd, 11% less than in 1995. Most of that water was self-supplied, and 82% was withdrawn from surface water. Withdrawals by state are shown in Table 2.8. Louisiana, Indiana, and Texas together consumed 38% of the nation's industrial water withdrawals. On a per capita basis, withdrawals of freshwater for industrial use equaled 19.7 billion gallons per day in 2000.

Most manufacturers use processed water at some point in the course of making a product. Water is the solvent in many chemical processes. In some plants, the item being manufactured is in contact with water at almost every step in its conversion from raw materials to finished product. For example, in the production of pulp and paper, water is used for removing bark from pulpwood, moving the ground wood and pulp from one process to another, cooking the wood chips for removal of lignin (the woody pulp of plant cells), and washing the pulp. Another example is the food industry, which uses huge quantities of water for cleaning and cooking vegetables and meat, canning and cooling canned products, and cleaning equipment and facilities.

The need for large quantities of easily accessible water has led to industrial development around or near coastlines, rivers, and lakes. The Great Lakes region and the Ohio River Valley are examples. This development has often caused serious deterioration of water quality in the area, since, after it is used, water may be returned to its source carrying contaminants.

MINING.

Mining is the extraction of naturally occurring materials, including petroleum, from the earth's crust. Water is used for washing and milling. Some withdrawals are actually the byproduct of mineral extraction and are considered an operational problem, since the water has to be removed from the mines. All water for mining operations is self-supplied, and may come from a freshwater or saline source. The USGS classifies water as saline if it has more than 1,000 parts per million of dissolved solids (salts).

The USGS estimated that 3,490 mgd of water were withdrawn for mining in 2000 (the latest data available), down from 3,770 mgd in 1995. Most water withdrawn for mining purposes was in the Texas Gulf area, followed by the Great Lakes region. Texas, Minnesota, and Wyoming together accounted for nearly half the mining withdrawals reported.

Acid mine drainage is a byproduct of mining activity. It is the drainage that results from the activity of removing and processing large amounts of natural strata to recover desired ores of heavy metals, minerals, and coal. Thousands of stream miles are severely affected by drainage and runoff from abandoned coal mines, which are the single largest source of adverse water-quality impacts to surface water and groundwater in the United States.

THERMOELECTRIC POWER.

The thermoelectric power generating sector is the largest user of withdrawal water. Water from both freshwater and saline sources is used in the generation of electric power with fossil fuel, nuclear, or geothermal energy. Most withdrawals are used for cooling condensers or reactors. As water flows through condensers or reactors, it absorbs and removes heat. There are several ways of disposing the heated water. One method is to channel it to a cooling tower or pond and reuse it. More than 60% of the water may be lost through evaporation during recycling, although newer recycling methods using cooling towers are much more efficient. Another method is to return the water directly to the source, resulting in an evaporation rate that is usually less than 2%. When water is returned to a lake or river at a significantly higher temperature than when it was withdrawn, however, it can damage aquatic life. For this reason, thermoelectric power plants are strictly regulated to ensure that return water is properly cooled before discharge.

FIGURE 2.4
Irrigation withdrawals, by source and state, 2000

Water used for thermoelectric power generation accounted for almost half (48%) of all withdrawals for off-stream use in 2000. (See Table 2.5.) The largest total withdrawals were in Texas. States in the eastern third of the country accounted for about 83% of the total. (See Figure 2.5.) If measured on a per capita basis, the water used for thermoelectric power generation in 2000 was 684 gallons per day.

WASTE DISPOSAL.

Although not traditionally recognized as a beneficial use, water has been used to dilute and disperse waste since the earliest human settlements. If the wastewater is properly treated, the water environment can dilute, disperse, and assimilate waste products without harm to water quality or aquatic communities. The first step in the process is to identify the total maximum daily load (TMDL) of contaminant that a water FIGURE 2.4
Irrigation withdrawals, by source and state, 2000 [CONTINUED]
SOURCE: Susan S. Hutson, Nancy L. Barber, Joan F. Kenny, Kristin S. Linsey, Deborah S. Lumia, and Molly A. Maupin, "Figure 7. Irrigation Withdrawals by Source and State, 2000," in Estimated Use of Water in the United States in 2000, U.S. Department of the Interior, U.S. Geological Survey, March 2004 (revised February 2005), http://water.usgs.gov/pubs/circ/2004/circ1268/ (accessed March 30, 2005) body can receive. The next step is to design, construct, and operate wastewater treatment facilities that provide the necessary level of treatment before discharging wastewater.

For the first (and last) time in 1995, the USGS reported wastewater releases and return flow. This category includes facilities that collect, treat, and dispose of water through sewer systems and wastewater treatment plants, generally to surface waters. About 16,400 publicly owned treatment facilities released some 41,000 mgd of treated wastewater nationwide in 1995. The annual average is one to two million gallons of treated water per facility per day. The largest wastewater return flows occurred in regions with large populations. Illinois (4,850 mgd) and Ohio (4,690 mgd) reported the largest releases of treated wastewater.

Not all treated wastewater is return flow. Because of the increasing demand for water and the cost of treating drinking water, more emphasis is being placed on water conservation and water reclamation (reuse). Reclaimed water is wastewater that has been treated for uses such as irrigation of golf courses or public parks instead of being discharged back to source waters. Florida (271 mgd), California (216 mgd), and Arizona (209 mgd) reported large uses of reclaimed wastewater in 1995 (the latest data available).

In November 2000 Congress gave impetus to water reuse practices in the Alternative Water Sources Act of 2000. These amendments to Title II of the Clean Water Act provide for "alternative water source projects" designed to provide municipal, industrial, and agricultural water supplies in an environmentally sustainable manner by conserving, managing, reclaiming, or reusing water or wastewater or by treating wastewater in areas where existing or reasonably anticipated future water supply needs cannot be met. A total of $75 million was authorized for 2003 to 2005 to implement this section, but the federal contribution to each project was limited to no more than 50%.

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