Guest Column | January 17, 2017

Reducing Water-Food Nexus Pressures In America


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:

  • Reduce loss and misuse
  • Optimize water use by ensuring reasonable allocation between various users while considering downstream users, both human and natural
  • Facilitate major financial and infrastructural savings
  • Reduce stress on water resources by reducing unsustainable consumption levels
  • Reduce water quality degradation

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:

  1. Facility A — for example, a wastewater treatment plant — needs to meet nutrient limits for its water quality permit, and therefore water quality trading is one option
  2. To reduce nutrients in the watershed, Facility A pays Farmer B to do a variety of things — for instance, reduce fertilizer used, plant stream-side buffers with trees, or keep livestock manure from getting into the waterways — with each conservation practice verified
  3. Nutrient reductions are quantified as credits — one credit equal to one pound of nutrient reduction, for example — which are then reviewed and approved by a regulatory agency
  4. Facility A can then use those credits to meet permit requirements


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: