By Robert C. Brears
Agricultural production is one of the most important sectors of the U.S. economy, contributing more than $300 billion to the country each year. When food service and other agriculture-related industries are included, this figure rises to over $750 billion. Crops grown across the country are not only critical for food security in the U.S., but also around the world; for instance, U.S. farms supply almost 25 percent of all grains (wheat, corn, rice, etc.) on the global market. However, the U.S. is likely to experience water shortages due to a variety of factors, including climate change and population and economic growth. In fact, a recent U.S. Government Accountability Office report indicates that 40 of 50 state water managers expect shortages in some portion of their states under average conditions in the next 10 years.
Agricultural impact on water quantity and quality
Already, agriculture is the largest user of ground and surface water in the U.S., accounting for around 80 percent of the nation’s consumptive water use and over 90 percent in many Western states. At the same time, agriculture is one of the largest sources of nonpoint source pollution in the U.S., impacting rivers, streams, and lakes as well as wetlands and groundwater supplies. Fertilizer and animal manure, both rich in nitrogen and phosphorus, are the primary sources of nutrient pollution from agricultural sources. Overall, excess nutrients can cause harmful algal blooms — overgrowth of algae in water — harming public health, creating dead zones in water, increasing water treatment costs, and impacting industries dependant on clean water.
Demand management to reduce water-food nexus pressures
To reduce water-food nexus pressures, water managers can implement demand management strategies to balance rising demand for limited, and often variable, supplies of good quality water, where demand management involves the better use of existing water supplies before plans are made to further increase supply. Demand management promotes water conservation during times of both normal conditions and uncertainty through changes in practices, cultures, and people’s attitudes towards water resources. Demand management aims to:
Pricing irrigation water in California
The Central California Irrigation District (CCID), which is one of the largest irrigation districts in the Central Valley and serves over 1,600 farms across more than 143,000 acres of farmland, has initiated new tiered water rates over the seven-month summer block of April 1 to October 31 (Table 1).
Table 1. Central California Irrigation District’s tiered water rates
Water quality trading in the Ohio River Basin
The Ohio River Basin Water Quality Trading Pilot Project is a first-of-its-kind interstate program that spans Ohio, Indiana, and Kentucky to evaluate the use of trading by industries, utilities, farmers, and others to meet water quality goals while minimizing costs. The water quality trading program, a market-based approach to achieving water quality goals, allows permitted discharges to generate or purchase pollution-reduction credits from another source. The premise of the water quality trading program is that:
With agricultural production already accounting for the majority of water consumption in the U.S. and water scarcity likely to affect nearly every state, water-food nexus pressures are likely to intensify in the coming decades. At the same time, agricultural production impacts the availability of good-quality water for other users. To reduce water-food nexus pressures, water managers can use a variety of demand management tools, such as pricing water to encourage conservation. At the same time, water managers can use a variety of demand management tools, including water quality trading, to reduce agricultural impacts on water quality.
About the Author
Robert C. Brears is the author of Urban Water Security (Wiley). Urban Water Security argues that, with climate change and rapid urbanization, cities need to transition from supply-side to demand-side management to achieve urban water security.
Image credit: "Delaware agriculture irrigation" University of Delaware Carvel REC © 2014, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/