Chapter 2C Main Ideas

1. Water Scarcity

Water stressed areas are those where there is water scarcity, water quality issues, or water is inaccessible. Much of the U.S. is under water stressed conditions due to water scarcity and agriculture needs for water have put increased pressure on available freshwater resources.

2. Strategies for Preventing Scarcity

Water scarcity can be combatted by increasing water supply through methods such as sand dams, groundwater recharge systems, and rainwater harvesting, or by decreasing the amount of water withdrawn. Methods for decreasing water withdrawals in agriculture include choosing an efficient irrigation type, choosing crops appropriate for the climate conditions, and maintaining healthy soils.

3. Water Quality Regulations

Water quality is regulated by the Clean Water Act of 1972, which prohibits point source pollution of waterways. However, most water quality contamination, including that from agricultural activities, is a result of nonpoint source pollution, which is not easily controlled or regulated.

4. Agricultural Impacts on Water Quality

Agricultural sources of water contamination include fertilizers and other nutrients, pesticides, animal feeding operations, livestock overgrazing, soil runoff, and excess irrigation. The impacts these contaminants have on water quality include cloudy water, poisoned water, pathogen filled water, and dead zones. The largest dead zone in the U.S. is in the Gulf of Mexico due to the influx of nutrients brought to this location from the Mississippi River, which has collected fertilizer and other nutrient runoff from much of the agricultural land across the central United States.

5. Strategies for Reducing Water Quality Impacts

Many of the strategies for reducing water quality impacts overlap with strategies for reducing water scarcity. Any method that reduces irrigation water will also lead to reduced runoff of agricultural contaminants. Reducing open soil areas, managing feedlots appropriately, creating riparian buffer zones, and monitoring and reducing nutrient application all reduce contaminant runoff.