Depletion and Conservation of Natural Resources - Erosion

Erosion is the process in which the materials of the Earth's crust are worn and carried away by wind, water, and other natural forces. The destruction of forests and native grasses has allowed water and wind greater opportunity to erode the soil. Changes in river flow and seepage from human technology have shifted the runoff patterns of water and the sediment load of rivers that, in turn, deposit into lakes and oceans. Erosion has become a problem in much of the world in areas that are overfarmed or where topsoil cannot be protected, such as on coasts, which are often overdeveloped.

Coastal Erosion

In Evaluation of Erosion Hazards, a study prepared for the Federal Emergency Management Agency in April 2000, the H. John Heinz III Center for Science, Economics, and the Environment, a nonprofit research organization, found that approximately 25 percent of structures within 500 feet of the U.S. coastline will suffer the effects of coastal erosion within 60 years. Especially hard hit will be areas along the Atlantic and Gulf of Mexico coasts, which are expected to suffer 60 percent of nationwide losses.

The nation's highest average erosion rates—up to six feet or more per year—occur along the Gulf of Mexico. The average erosion rate on the Atlantic coast is two to three feet per year. A major storm can erode 100 feet of coastline in a day. The Heinz Center estimates that roughly 10,000 structures are within the estimated ten-year erosion zone closest to the shore. This does not include structures in the densest areas of large coastal cities, such as New York, Chicago, Los Angeles, and Miami, which are heavily protected against erosion.

The powerful effects of erosion were dramatized by the predicament of the Cape Hatteras lighthouse in North Carolina. When it was constructed in 1870 the lighthouse was 1,500 feet from the shore. By 1987 the lighthouse stood only 160 feet from the sea and was in danger of collapsing. In 1999 the National Park Service, at a cost of $9.8 million, successfully moved the lighthouse back 2,900 feet.

Erosion of beaches on the East Coast is becoming a more serious problem as development inches closer to the ocean. The Army Corps of Engineers has been rebuilding eroded beaches since the 1950s. The federal government pays 65 percent of the cost of beach rebuilding, with states and local governments paying the remaining 35 percent. Many experts, however, believe that beach replenishment is a futile effort and that funds could be better spent elsewhere.

Soil Erosion and Agriculture

Agricultural lands are the principal source of eroded soil. According to the U.S. Department of Agriculture (USDA), approximately 20 percent of the nation's land is set aside for cropland. Three-quarters of this land is actively used to grow crops for harvesting. The remainder is used for pasture or is idled for various reasons. This would include cropland enrolled in the Federal Conservation Reserve Program (CRP). (See Figure 9.7.)

Demands on the Earth to feed growing populations and changes in the Earth's landscape caused by human activities have speeded up soil erosion. Soil erosion has increased to the point where it far exceeds the natural formation of new soil, and experts consider the problem to be of epidemic proportions. According to Excessive Erosion on Cropland, 1997 (2000) the USDA's Natural Resources Conservation Service found that 108 million acres were eroding excessively.

FARMING PRACTICES.

Agriculture depends primarily on the top six to eight inches of topsoil. Fields planted in rows, such as corn, are most susceptible to soil runoff. In 2002 corn comprised 22 percent of total acres used for crops in the United States. Cover crops, such as hay, provide more soil cover to hold the land. Hay crops accounted for 17 percent of total acres used for crops in 2002. (See Figure 8.3 in Chapter 8.)

FIGURE 9.7
Land use, 1997

Historically, when most of the topsoil was lost farmers would abandon the land. Now, however, farmers continue to plow the soil, even when it consists of as much subsoil as topsoil. It costs more money to produce food on such land than on land where topsoil is present. Farmers often use more fertilizer to make up for the decreasing productivity of the soil, and that, in turn, adds to environmental pollution.

The GAO estimates that about 28 percent of the nation's cropland is highly erodible. The states with the highest percentage of highly erodible cropland are New Mexico (90 percent), Arizona (81 percent), and Colorado (77 percent). In absolute terms Texas and Montana have the most erodible land. The amount of erosion has declined in past decades. The USDA attributes the decline to the CRP, which pays farmers to take land out of production for ten years, and to the Conservation Compliance Program. As part of the 1985 Farm Act (PL 99-198), the Conservation Compliance Program was initiated as a major policy tool. To be eligible for agricultural program benefits, farmers must meet minimum levels of conservation on highly erodible land.

ENVIRONMENTAL QUALITY INCENTIVES PROGRAM.

Congress, under the 1996 Farm Bill (PL 104-127), authorized the Environmental Quality Incentives Program (EQIP) to address agriculture's natural resource and environmental problems. It is a flexible, voluntary, and effective conservation program that allocates millions of dollars each year to farmers' conservation efforts. EQIP was reauthorized in the Farm Security and Rural Investment Act of 2002 (Farm Bill).

Under EQIP the USDA provides assistance to family-sized farms and ranches for up to 75 percent of the cost of certain environmental protection practices, such as grassed waterways, filter strips, manure management facilities, capping abandoned wells, and wildlife habitat enhancement. The USDA may also offer incentive payments to encourage producers to apply such land management practices to the use of nutrients, manure, irrigation water, wildlife, and integrated pest management.