Issues of Water Quality and Quantity in Agriculture
Agustina Beseda -‐ Roa Elbizri -‐ Karen Mahrous -‐ Nesmarie Negron Introduction A major challenge to global agricultural production is to meet the growing demands of increasing population and changes in diets while maintaining valuable resources and limiting pollution and degradation to the environment (OECD, 2012). Water pollution, the limitations on the availability of clean water, and the demand for elaborate irrigation structures are some of these important challenges that must be addressed. Ceres sites unsustainable water use as one of the top three threats to corn production in the United States (Barton & Clark, 2014). Unsustainable water use comprises two main threats to agricultural production, water quality and availability of usable water. Several technologies, management techniques and government, market and consumer practices exist to encourage farmers to adopt more sustainable agricultural practices, and in turn, alleviate the challenges associated with water use and quality in the agriculture sector. Sustainable management of water in agriculture is critical to increase agricultural production and to ensure that waters maintain other designated uses. There are several regulations and policies in place at both the federal and state level to address water quality and quantity issues related to agriculture irrigation. 1.0 Water Quality In addition to water being depleted from existing aquifers at an increasing rate for irrigation, the quality of water sources is compromised due to inefficient farming practices. Although circumstances vary greatly, agriculture is often cited as the leading source of water pollution (OECD, 2012). Agricultural practices cause pollutants to enter the water stream through various processes including dissolving (leaching), soil erosion and sediment (runoff), and through gaseous release (volatilisation) (OECD, 2012). In the U.S., corn production is one of the largest pollutants of water sources. Because of the importance placed on and the demanding market for corn in the U.S., it uses the most fertilizer of any U.S. crops. As an illustration of this, in 2010, corn production in the U.S. used 9.5 million tons of nitrogen, phosphorous, and potash (Barton & Clark, 2014). The nitrogen run-‐off from these cornfields is the largest contributor to pollution in the Gulf of Mexico. The “dead zone” is a portion of the Gulf that is as large as the state of Connecticut and is completely hypoxic. The dead zone is caused by run-‐off from agricultural chemicals and waste that flows through the Mississippi River Basin into the Gulf of Mexico. Figure 1 below shows the massive reach of the Gulf of Mexico dead zone, which is one of the largest dead zones in the world.
Figure 1. Gulf of Mexico Dead Zone as of July 2013
Source: Rabalais & Turner, Louisiana State Universities Marine Consortium, Sponsored by NOAA, Center for Sponsored Coastal Ocean Research.
Sources of water pollution, and the cause of dead-‐zones all over the world like the one in the Gulf of Mexico, can be attributed primarily to agricultural activities. As the demand for agricultural intensification increases and arable land resources decrease, the use of chemicals becomes more engrained in the agricultural process. These chemicals can have varying effects from causing hypoxia in bodies of water to contaminating drinking and irrigation water. And because of the limited regulation on agricultural run-‐off in the U.S., the burden to clean the water streams is placed on the industries affected by the pollution, such as fisheries and water utilities. The USDA estimates that the cost of removing nitrates from drinking water is approximately $4.8 billion per year and is paid largely by the utilities. The effects of nutrient pollution from agricultural practices also reaches aquatic ecosystems, fisheries and other commercial uses, recreational activities and, of course, human health. Figure 2 shows the sources of water pollution from agricultural activities. The harm caused by fertilizers and other agricultural chemicals can be mitigated by using best practices for chemical application and run-‐off management. According to the USDA, only 34% of corn acres are farmed using these best practices. Some of these practices include not over-‐applying fertilizers and applying at the right time during the growing season (Barton & Clark, 2014). Additionally, longer crop rotations, cover-‐cropping, and use of man-‐made wetlands on farmlands could not only reduce run-‐off and the use of fertilizers, but also reduce the need for pesticides and preserve soil health. Figure 2. Agricultural Pollutants.
Source: OECD, “Agriculture and Water Quality: Sources, Trends, Outlook and Monitoring” 2012
2.0 Water Quantity Development Needs Given population and income growth, it is widely expected that the agricultural sector will have to expand the use of water for irrigation to meet rising food demand; at the same time, the competition for water resources is growing in many regions. (Scheierling, Treguer, Booker, Decker, 2014). Every country has a relatively fixed amount of internal water resources, defined as the average annual flow of rivers and aquifers generated from precipitation. Over time, this internal renewable supply must be divided among more and more people, eventually resulting in water scarcity (FAO, 1993). The following graphic shows the water availability per capita by region from 1950 to 2000:
Figure 3. Water Availability per Capita by Region
Water Availability Per capita by Region Per Capita *000m3
120 Africa
100 80
Asia
60
La3n America
40
Europe
20
North America
0 1950
1960
1970
1980
2000
Graph created with information from source: N.B. Ayibotele. 1992. The world's water: assessing the resource. Keynote paper at the ICWE, Dublin, Ireland. http://www.fao.org/docrep/003/t0800e/t0800e0a.htm
Most countries facing chronic water scarcity problems are in North Africa, the Near East and sub-‐Saharan Africa. Countries with less than 2,000 cubic meters per capita face a serious marginal water scarcity situation, with major problems occurring in drought years. By the end of the 1990s, water availability is expected to fall below 2,000 cubic meters per capita in more than 40 countries. In many countries, while scarcity is less of a problem at a national level, serious water shortages are causing difficulties in specific regions and watersheds. Notable examples include northern China, western and southern India and parts of Mexico. (FAO, 1993). The following image shows the water scarcity situation globally. The most critical areas are indicated in blue; while in light blue the areas approaching physical water scarcity. Figure 4. Global Water Scarcity
Source: World Water Development Report 4. World Water Assessment Programme (WWAP), March 2012.
Given the critical importance of water to individuals, economies, and societies, water stress can lead to significant political and social tensions. Competition for limited water resources can create tensions among different users within a country, and also between countries (World Savvy, 2009). International water conflicts are related to a wide range of other socio-‐political tensions, such as border disputes or mega-‐projects such as dams and reservoirs, environmental problems, or political identity (Tamas, 2003). Overall, the relationship between water and agriculture is dichotomous. On one hand, agriculture has an important role on global water crises. Two basic facts are critical for understanding this role. First, the agricultural sector is by far the largest user of water (Scheierling, Treguer, Booker, Decker, 2014). Worldwide, irrigated agriculture accounts for about 70 percent of total freshwater withdrawals (Molden, 2007). An estimated 20 percent of cultivated land is irrigated, accounting for 40 percent of total agricultural production (Rosegrant et al., 2009), and, second, water use in agriculture also tends to have relatively low net returns as compared to other uses (Young, 2005). On the other hand, the global water crisis is contributing to an unprecedented global agricultural crisis. The availability of irrigation water is a major factor in this regard, especially when other factors, such as the impacts from climate change, are also taken into account (World Bank, 2012). Climate change is expected to account for about 20 percent of the global increase in water scarcity. Countries that already suffer from water shortages will be hit hardest. The impact of a changing climate will affect not only bulk water availability but also worsen extremes of drought and floods (UN Water, 2007). Risks Climate change can affect both supply and demand for water in agriculture. Water supply can be directly impacted by climate change through changes in rainfall patterns, and indirectly, through changes in water compartments such as surface water, groundwater, snow and glaciers that can be used for the purpose of agricultural water withdrawals, including irrigation and livestock. Water demand by agriculture can also be modified due to changes in cropping and livestock system for adaptation purposes and changes in crop water requirements driven by climatic variables such as high temperatures and winds. Therefore, climate change can affect not only water availability, but also can modify crop water requirements (OECD, 2014). Another challenge that agriculture has to face is how to best support stakeholders in managing their water demands in a context of increasing competition and interdependence. The indiscriminate use of a purely economic approach risks overemphasizing monetary expressions of value at the expense of environmental and social values (UN Water, 2007). Market According to the OECD Environmental Outlook to 2050 (OECD, 2012), the baseline scenario projects a 55% increase in global water demand, from 3,500 cubic
kilometers in 2000 to 5,500 cubic kilometers in 2050, most of this increase comes from manufacturing, electricity and domestic use (OECD, 2014). Most countries rely on a mix of market policies and direct government interventions to manage water resources. Each system has its own advantages and disadvantages. While the private market has the potential to produce the maximum private-‐valued bundle of goods and services, the public sector also plays an important role. Public actions incorporate a broader range of social goals than the private sector There is a major discrepancy in the cost of the water in the world (Water.org). For example, in EU, water for municipal uses, including connected industries, commercial and tourist purposes is sold at full financial cost, while irrigation water is sold at 50% of the full financial cost (European Commission, 2012). And, on the other hand, agriculture is often unable to compete economically for scarce water. Cities and industries can afford to pay more for water and earn a higher economic rate of return from a unit of water than does agriculture (FAO, 1993). 3.0 Market Solutions There are a number of potential solutions for improving agricultural water management, thereby controlling the quantity of water used for irrigation, and reducing the adverse impact of irrigation and other farming practices on the quality of nearby water bodies. Farm Level At the farm level, many innovations have reduced the need for chemical input, which affect the water quality of nearby water bodies via runoff. The organic or biological farming movement is stirring farmers away from synthetic chemicals and fertilizers and more towards crop rotation, mulching, and cover cropping, and integrated pest management. Crop rotation avoids depleting soil nutrients, and similar to other less invasive tillage practices, it leaves varying amounts of crop residue or mulch on the soil, which increases the amount of organic matter in the soil and reduces the need for synthetic fertilizers that otherwise may be excessively applied and end up in runoff. Another biological farming method is cover cropping, whereby the soil is covered with clover, vetch and other nitrogen-‐fixing plants in order to enhance soil health without the use of synthetic fertilizers (UNEP, 2010). Similarly, in order to reduce the application of pesticides, which may also end up in nearby water bodies due to runoff, farmers are applying integrated pest management (IPM) techniques. Through IPM, particular farming practices and beneficial insects are used to control pests instead of chemical pesticides. These farming practices include watching crops closely to remove diseased or damaged crops, using mechanical methods to remove pests such as using traps and tillage to disrupt reproduction and breeding of pests, and using natural controls such as beneficial insects and fungi to control pests. In some cases, chemical pesticides may be used, but they are specific to a particular type of pest, and are thus applied in smaller amounts in comparison to broad-‐spectrum pesticides (US EPA, 2014).
Finally, reducing the total amount of water that is applied to the farm reduces water stress and decreases the leaching of nitrates from fertilizers as well as other chemicals into water bodies. Improved irrigation technologies such as drip irrigation and other micro-‐irrigation methods can aid in reducing the amount of water applied to the crops on the farm. One such micro-‐irrigation system is trickle irrigation, also referred to as drip irrigation. Trickle irrigation is “a low-‐pressure system, which places water slowly and directly in the root zone of the desired plant or crop, increasing the efficiency of the water applied.” Trickle irrigation can reduce water use by 30 to 70 percent compared to more traditional means of irrigation, such as overhead sprinklers. Similarly, micro-‐sprinkler irrigation systems “distribute water uniformly to a crop via low volume, low pressure output devices that control the rate of water output.” The advantages of this irrigation system include water conservation, energy efficiency, area between crop rows remains drier facilitating spraying and harvesting, and reduced labor (Harrison, 2012). There are also certain technologies, associated with precision farming, that farmers are able to currently use to determine precisely and control the amount of water that is applied to crops, therefore reducing the total amount of water used on the farm. These technologies include remote sensors on aircrafts and satellites, which assess numerous growing conditions, including which crops are thriving and don’t require additional water versus ones that should be watered, hence eliminating wide-‐spread, untargeted irrigation. GPS systems also allow farmers to map field boundaries, roads, irrigation systems, and problem areas in crops. This allows farmers to install irrigation systems precisely where the crops are located and turn them on only in locations where needed. Variable rate technologies are also devices mounted on tractors and programmed to control the amount of water dispersed based on the information received from the remote sensors and GPS systems (NOAA, 2013). Basin Level At the basin level, control methods should be in place for inevitable agricultural runoff. The types and locations of different land uses should be considered to protect the water quality, as steep slopes, for example, facilitate runoff of water along with other sediments and agricultural chemicals. Contour farming and terracing can be used by farmers to reduce erosion and runoff from agricultural lands. These two methods are particularly critical in areas with steep slopes. Another solution related to water quantity at the basin level has to do with the collective water management districts that many farmers receive their water from. These organizations can provide services to farmers that facilitate the transformation of their irrigation systems into more efficient ones. For example, in order to install a drip irrigation system, water must be delivered through pressurized pipes; however, most water is usually delivered to farmers via open canal systems, and water delivery organizations would have to update their infrastructure to give farmers the option to switch to more efficient irrigation technologies. These water delivery organizations also hold the responsibility to track water use as well as water quality, and to intervene when necessary (UNEP, 2010).
National and State Level In addition to setting standards as well as developing and enforcing policies for agricultural practices, as previously mentioned, nations and states can help farmers implement innovative practices through technical outreach, assistance and training. This can be done through training government staff and, in turn farmers, on techniques to reduce adverse effects on water quality, such as the implementation of biological and integrated pest management as well as other methods to reduce erosion and runoff of chemicals into water bodies. Governments can also provide financial incentives for farmers to adopt farming techniques that are less water intensive. These financial incentives include providing grants and loans for farmers to upgrade infrastructure and install more efficient irrigation systems, such as drip irrigation (Governing Institute, 2013). Consumer Level Consumer and investor pressure on the private sector can also be a means to change water practices. This pressure may be in the form of boycotts of crops from certain farms, as well as media campaigns that publicize the poor water practices of companies and their suppliers, including farmers, and places them under the spotlight to address their poor water management practices. Market Level Certain existing market level mechanisms help achieve water quality through water pollution charges and water quality trading. Water pollution charges require that polluters pay for their discharges based on the quantity and type of pollutants discharged. These fees will eventually encourage farmers to invest in treatment technologies and other water pollution reduction techniques, which will cost them less than paying the fee for polluting. It is important that the charge be sufficiently high to create an incentive for polluters (GWP, 2012). Water quality trading is another market level approach, which allows polluters with high-‐abatement costs to pay polluters with low-‐abatement costs in order to reduce the discharge of certain pollutants. In order to encourage trading, a water quality policy must be present, and a cap must exist on the concentration of pollutants allowable in a water body. Trading is allowed between any two point and nonpoint sources of water pollution that are in the same watershed (US EPA, 2014). For example, in the Lake Taupo Trading Program in New Zealand, allowable nitrogen runoff has been allocated on an acre-‐basis, and farmers that want to increase their nitrogen use must purchase credits from other farmers in the basin. Care must be taken with such trade systems, however, to ensure that pollution trading will not lead to high concentrations of pollutants in poor and minority communities if the cost of pollution abatement is correlated with income or race (UNEP, 2010). 4.0 Policy and Regulation Policy on Water Quality
The water quality policy in the U.S. is primarily framed around the Clean Water Act (CWA) passed in 1972, which authorized the U.S. Environmental Protection Agency (EPA) to address water quality by reducing pollution and protecting its uses such as fishing, swimming, and aquatic life. The federal level sets the standards and states are primarily responsible for establishing the policies for meeting those standards (Reimer, 2012). The CWA Section 319 program is the primary federal mechanism for addressing nonpoint sources in the U.S., which include pollution from agricultural activities. Under Section 319, states, territories and tribes receive grant money that supports activities including technical assistance, financial assistance, education, training, technology transfer, demonstration projects and monitoring to assess the success of specific nonpoint source implementation projects (EPA, 2014). At the federal and state levels of policy, the US has largely chosen to address water pollution from agriculture through voluntary programs, which support farmers in installing best management practices (BMPs) (EPA, 2014). The National Water Quality Initiative is the most recent federal and state effort to address irrigation water pollution. The United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS), the EPA, and state water quality agencies collaborated to select high-‐priority watersheds in each state. These priority watersheds will receive targeted financial and technical assistance to improve water quality through conservation systems (USDA, 2013). As indicated in Figure 5 below, there has been an overall increase in payment policies that are supported by technical advice to farmers (OECD, 2012). While there have been documented successes of these voluntary programs, some states have decided that the voluntary measures are insufficient, and have opted to regulate water pollution stemming from crops fields (Perez, 2011). For example, Delaware, Maryland and Virginia passed regulations requiring nutrient management plans after 1997 Chesapeake fish kills were linked to nutrient pollution from crop fields resulting in improvements in nutrient reduction (Perez, 2011). In addition, the California Environmental Protection Agency, through the Irrigated Lands Regulatory Program (ILRP) regulates discharges from irrigated agricultural lands by issuing waste discharge requirements or orders, which contain conditions requiring water quality monitoring of receiving waters and corrective actions when impairments are found. The number of acres of agricultural land enrolled in the ILRP is about six million acres (California EPA, 2014).
Figure 5. Trends in the U.S. Agri-‐environmental Conservation Payments: 1985-‐2012
Policy on Water Quantity Nearly 85% of U.S. irrigated water, which comes primarily from groundwater sources, is used in 17 western states (Reimer, 2012). Most of the irrigated water in the western United States is developed and delivered by the U.S. Bureau of Reclamation and state departments of water resources, both of which have contractual relationships with irrigation districts (water user associations) that represent groups of farmers (Wichelns, 2010). The irrigation districts collect fees from their members, in return for providing water delivery services. Water rights are determined, issued, and managed by state governments and in most western states, water rights are defined in conjunction with land ownership. Some states, like Nebraska, require Natural Resource Districts (NRDs) to develop groundwater management plans that identify ways each NRD will regulate groundwater uses (University of Nebraska-‐Lincoln, 2014). Other states, however, do not regulate how much groundwater famers withdraw, giving exemptions for groundwater permits when used for irrigation (Washington State Department of Ecology, 2014). Groundwater supply policy is primarily driven by states, with federal leadership and funding supporting state actions. These policies and programs to promote improve management include public incentive programs, such as cost sharing and technical assistance for water conservation measures and the development of water conservation plans. The cost sharing programs are provided by the USDA’s Environmental Quality Incentives Program (EQIP), U.S. Department of the Interior’s
Bureau of Reclamation as well as state and local governments and require water conservation plans to qualify for funding (Aillery and Gollehon, 2012). Nationally, irrigation practices accounted for roughly a quarter of total EQIP funding obligations ($5.7 billion) from 2004 to 2010 (USDA, 2013). Some of the water policy reforms being evaluated to improve water management in irrigated agriculture include quantity-‐based regulation, price-‐based regulation, transferable water use permits and conservation subsidies (Moore, 1991). It is argued that because irrigated water demand is slightly inelastic, prices would have to increase significantly to change consumption behavior and the substitution of groundwater supplies may further limit the effectiveness of the public water-‐pricing policy on conservation (Aillery and Gollehon, 2012). Studies have indicated that behavior is dictated by water prices in some water districts and water supply in other districts (Moore, 1991). Therefore, the USDA Economic Research Service argues that water-‐pricing policy would be more effective alongside other programs to effect technology and crop production behavior. Water transfers are market provisions for the sale of water rights or temporary lease of water (Aillery and Gollehon, 2012) Some states have assisted farmers in obtaining water during droughts by creating centralized “water banks” in which buyers and sellers can exchange information and conduct transactions (Wichelns, 2010) For example, hundreds of water transfers occur in California between agricultural water users in the same basin to help address water supply shortages (California Department of Water Resources, 2014). 5.0 Conclusions Farmers should determine the water management techniques that best fit the needs of their farms as well as reduce the use of surplus water and decrease the adverse effect of their agricultural practices, including irrigation and cultivation, on the water quality of surrounding water bodies. While there are many programs in place to address both water quality and quantity issues related to irrigation, there are limitations which prevent any single policy from providing the economic efficiency and environmental effectiveness needed to conserve water. Therefore using a mix of policy instruments to address water quality and quantity issues in agriculture is more likely to be successful (OECD, 2012).
Works Cited Barton, B., & Clark, S. E. (2014). Water & Climate Risks Facing U.S. Corn Production. Ceres. A Ceres Report. Moore, M. R. (1991). The Bureau of Reclamation's New Mandate for Irrigation Water Conservation: Purposes and Policy Alternatives. Water Resources Research, Vol 27, No 12, 145-‐155. National Oceanic and Atmospheric Administration. (2014, June 15). Agriculture. Retrieved from http://www.gps.gov/applications/agriculture/ OECD. (2012). Agriculture and water quality: Sources, trends, outlook and monitoring. In OECD, Water Quality and Agriculture, Meeting the Policy Challenge. OECD Publishing. OECD. (2012). Executive Summary. In OECD, Water Quality and Agriculture, Meeting the Policy Challenge. OECD Publishing. Osteen, C., Gottlieb, J., & Vasavada, U. (2012). Agricultural Resources and Environmental Indicators. United States Department of Agriculture. Perez, M. (2011). Regulating Farm Non-‐Point Source Pollution: The Inevitability of Regulatory Capture and Conflict of Interest? World Resources Institute. Rabalais, N., & Turner, R. (2013). Gulf of Mexico Hypoxia. Louisiana Universities Marine Consortium. Louisiana State University. Reiner, A. (2012). U.S. Water Policy: Trends and Future Directions. National Agricultural and Rural Development Policy Center. Scheierling, S. M., Treguer, D. O., Booker, J. F., & Decker, E. (2014). How to Assess Agricultural Water Productivity? World Bank Group. World Bank Group. Retrieved July 2014, from http://www-‐ wds.worldbank.org/external/default/WDSContentServer/IW3P/IB/2014/0 7/28/000158349_20140728161059/Rendered/PDF/WPS6982.pdf United Nations. (2007). Coping with water scarcity. Challenge of the twenty-‐first century. . UN Water. Retrieved August 2014, from http://www.fao.org/nr/water/docs/escarcity.pdf United Nations. (2014). UN Water. Retrieved from www.un.org/waterforlifedecade United Nations Environment Programme. (2010). Clearing the Water: A Focus on Water Quality Solutions. UNEP. United States Department of Agriculture, Economic Research Service. (n.d.). Retrieved from http://www.ers.usda.gov/topics/farm-‐practices-‐ management/irrigation-‐water-‐use/background.aspx#.U-‐JMHfldWcI. United States Environmental Protection Agency. (2014). Pesticides: Regulating Pesticides. Retrieved from http://www.epa.gov/oppbppd1/biopesticides/whatarebiopesticides.htm United States Environmental Protection Agency. (2014). Water Quality Trading. Retrieved from http://water.epa.gov/type/watersheds/trading.cfm
Washington State Department of Ecology. (2014). Find out if your project is exempt from a water right permit. Retrieved from http://www.ecy.wa.gov/programs/wr/comp_enforce/gwpe.html Water.org. (n.d.). Water Facts: Economics. Retrieved from http://water.org/water-‐ crisis/water-‐facts/economics/ Wichelns, D. (2010). Agricultural Water Pricing: United States. OECD. World Savvy Monitor. (2009, November). Water, Politics, and Conflict: Overview. Retrieved from http://worldsavvy.org/monitor/index.php?option=com_content&view=artic le&id=721&Itemid=1210 Young, R. A. (2005). Determining the Economic Value of Water. RFF Press.