Hydrogeology. Kevin M. Hiscock

Fig. 1.12 Trends in water abstractions (fresh and saline) by water use category and total (fresh and saline) abstractions in the United States from 1960 to 2000 (Solley et al. 1998 and Hutson et al. 2004).

      (Sources: Adapted from Solley, W.B., Pierce, R.R. and Perlman, H.A. (1998) Estimated use of water in the United States in 1995. United States Geological Survey Circular 1200, 71 pp; Hutson, S.S., Barber, N.L., Kenny, J.F. et al. (2004) Estimated use of water in the United States in 2000. United States Geological Survey Circular 1268, 46 pp.)

The abstraction of fresh and saline water in the United States from 1960 to 2000 as reported by Solley et al. (1998) and Hutson et al. (2004) is shown in Fig. 1.12. The estimated total abstraction for 1995 is 1522 × 10⁶ m³ day⁻¹ for all offstream uses (all uses except water used instream for hydroelectric power generation) and is 10% less than the 1980 peak estimate. This total has varied by less than 3% since 1985. In 2000, the estimated total water use in the United States is 1544 × 10⁶ m³ day⁻¹. Estimates of abstraction by source indicate that during 1995, total fresh surface water abstractions were 996 × 10⁶ m³ day⁻¹ and total groundwater abstractions were 293 × 10⁶ m³ day⁻¹ (or 23% of the combined freshwater abstractions). The respective figures for 2000 are 991 × 10⁶ m³ day⁻¹ and 316 × 10⁶ m³ day⁻¹, with 24% of freshwater abstractions from groundwater.

      Total water abstraction for public water supply in the United States in 2000 is estimated to have been 163 × 10⁶ m³ day⁻¹, an 8% increase since 1995. This increase compares with a 7% growth in the population for the same period. Per capita public water supply use increased from about 678 L day⁻¹ in 1995 to 683 L day⁻¹ in 2000, but is still less than the per capita consumption of 696 L day⁻¹ recorded for 1990.

The two largest water use categories in 2000 were cooling water for thermoelectric power generation (738 × 10⁶ m³ day⁻¹ of fresh and saline water) and irrigation (518 × 10⁶ m³ day⁻¹ of freshwater). Of these two categories, irrigation accounts for the greater abstraction of freshwater. The area of irrigated land increased nearly 7% between 1995 and 2000 with an increase in freshwater abstraction of 2% for this water use category. The area irrigated with sprinkler and micro‐irrigation systems has continued to rise and now comprises more than half of the total. In 2000, surface water was the primary source of irrigation water in the arid West and the Mountain States and groundwater was the primary source in the Central States. California, Idaho, Colorado and Nebraska combined accounted for one‐half of the total irrigation water abstractions. California and Idaho accounted for 40% of surface water abstractions and California and Nebraska accounted for one‐third of groundwater abstractions. In general, groundwater abstractions for irrigation have increased significantly. In 1950, groundwater accounted for 23% of total irrigation water, while in 2000 it accounted for 42%.

      1.7.3.1 Management and protection of groundwater resources in the United States

      Groundwater management in the United States is highly fragmented, with responsibilities shared among a large number of federal, state and local programmes. At each level of government, unique legal authorities allow for the control of one or more threats to groundwater, such as groundwater contamination arising from municipal, industrial, mining and agricultural activities.

      Beginning with the 1972 amendments to the federal Water Pollution Control Act, and followed by the Safe Drinking Water Act 1974, the federal government’s role in groundwater management has increased. The introduction of the Resource Conservation and Recovery Act (RCRA) 1976 and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) 1980, established the federal government's current focus on groundwater remediation. With these acts, the federal government has directed billions of dollars in public and private resources towards cleaning up contaminated groundwater at ‘Superfund’ sites, RCRA corrective action facilities and leaking underground storage tanks. In 1994, the National Academy of Sciences estimated that over a trillion dollars, or approximately $4000 per person in the United States, will be spent in the next 30 years on remediating contaminated soil and groundwater.

      The approach to groundwater protection at the federal level has left the management of many contaminant threats, for example hazardous materials used by light industries (such as dry cleaners, printers or car maintenance workshops), to state and local government authorities. Other groundwater threats, such as over‐abstraction, are not generally addressed under federal law, but left to states and local governments to manage.

      In 1984, the US Environmental Protection Agency (USEPA) created the Office of Ground Water Protection to initiate a more comprehensive groundwater resource protection approach and to lead programmes aimed at resource protection. Such programmes include the Wellhead Protection and Sole Source Aquifer Programs, which were established by Amendments to the Safe Drinking Water Act 1986. The Wellhead Protection Program (WHPP) encourages communities to protect their groundwater resources used for drinking water. The Sole Source Aquifer Program limits federal activities that could contaminate important sources of groundwater.

      State groundwater management programmes are seen as critical to the future achievement of effective and sustainable protection of groundwater resources. In 1991, the USEPA established a Ground Water Strategy to place greater emphasis on comprehensive state management of groundwater as a resource through the promotion of Comprehensive State Ground Water Protection Programs (CSGWPPs) together with better alignment of federal programmes with state groundwater resource protection priorities (USEPA 1992).

      1.7.4 Groundwater abstraction in China

The rapidly growing economy of China, with about 20% of the world’s population but only about 5–7% of global freshwater resources, has a high demand for groundwater. Groundwater is used to irrigate more than 40% of China's farmland and supplies about 70% of drinking water in the dry northern and north‐western regions, with the past few decades having seen groundwater extraction increase by about 2.5 × 10⁹ m³ a⁻¹ to meet these needs. Consequently, groundwater levels below the arid North China Plain have dropped by as much as 1 m a⁻¹ between 1974 and 2000 (Qiu 2010). Further discussion of the significance of groundwater leading to economic development in the rural and expanding urban areas underlain by the Quaternary Aquifer of the North China Plain is presented in Box 1.5.

      Currently, the largest threat to sustainable water supplies in China is the growing geographical mismatch between agricultural development and water resources. The centre of grain production in China has moved from the humid south to the water‐scarce north over the past 30 years, as southern cropland is urbanized and more land is irrigated further north. As the north has become drier, increased food production in this region has largely relied on unsustainable overuse of local water resources, especially groundwater. Wasteful irrigation infrastructure, poorly managed water use, as well as fast industrialization and urbanization, have led to a serious depletion of groundwater aquifers, loss of natural habitats and water pollution (Yu 2011).

To provide more sustainable management of groundwater resources, China needs