Trends in Nutrient and Soil Loss in Illinois Rivers, 1978–2017

Trends in Nutrient and Soil Loss in Illinois Rivers, 1978–2017 Scientific Investigations Report 2020–5041 U.S. Department of the Interior U.S. Geological Survey Cover photo. Winter sunrise over the Embarras River (03344000) near Fox Ridge State Park, Illinois (Photograph by Rebecca Meerdink). Trends in Nutrient and Soil Loss in Illinois Rivers, 1978–2017 By Timothy O. Hodson and Paul J. Terrio Scientific Investigations Report 2020–5041 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DAVID BERNHARDT, Secretary U.S. Geological Survey James F. Reilly II, Director U.S. Geological Survey, Reston, Virginia: 2020 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Hodson, T.O., and Terrio, P.J., 2020, Trends in nutrient and soil loss in Illinois rivers, 1978–2017: U.S. Geological Survey Scientific Investigations Report 2020–5041, 26 p., https://doi.org/ 10.3133/ sir20205041. ISSN 2328-0328 (online) iii Acknowledgments This report would not have been possible without the committed efforts of the personnel at the Illinois Environmental Protection Agency, U.S. Geological Survey, and the Illinois State Water Survey who collected and processed tens of thousands of water samples as part of the Ambient Water Quality Monitoring Network program. The authors also thank Gregg Good, Roy Smogor, Matt Short, Trevor Sample, and Missy Cain (all Illinois Environmental Protection Agency) for their assistance in compiling Ambient Water Quality Monitoring Network data and for providing their insights into its interpretation. v Contents Acknowledgments ........................................................................................................................................iii Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................1 Methods...........................................................................................................................................................4 Data Compilation ��4 Trend Analysis ��4 Trends in Nutrient and Soil Loss in Illinois Rivers, 1978–2017 ................................................................5 Phosphorus, 1978–2017 ........................................................................................................................5 Phosphorus, 2008–17 ��7 Nitrogen, 1978–2017..............................................................................................................................8 Nitrogen, 2008–17..................................................................................................................................8 Total Suspended Solids, 1978–2017 ...................................................................................................8 Total Suspended Solids, 2008–17 .......................................................................................................8 Synopsis and Implications of Trends in Nutrient and Soil Loss .............................................................8 Trends during 1978–2017 ......................................................................................................................8 Trends during 2008–17 ........................................................................................................................10 Summary........................................................................................................................................................11 References ....................................................................................................................................................11 Appendix 1 Ambient Water Quality Monitoring Network Monitoring Site Information ................15 Appendix 2 Supplementary Figures ......................................................................................................17 Figures 1. Map showing locations of Ambient Water Quality Monitoring Network water-quality monitoring sites ....................................................................................................3 2. Maps of changes in flow-normalized concentration, flux, and yield of total phosphorus, total nitrogen, and total suspended solids ........................................................6 3. Boxplots showing statewide change in nutrient and total suspended solids fluxes for each trend component ...............................................................................................7 4. Maps showing change in corn and soybean area and production, as well as population change, among counties in Illinois, 1978–2017 ....................................................9 Tables 1. Major river basins in Illinois, their farthest downstream Ambient Water Quality Monitoring Network identification, and the corresponding U.S. Geological Survey streamgage station number ..........................................................................................5 2. Change in flow-normalized yield for each major river basin ��7 vi Conversion Factors International System of Units to U.S. customary units Multiply By To obtain Area square kilometer (km2) 247.1 acre Mass gigagram (Gg) 1,000 metric ton (t) kilogram (kg) 2.205 pound avoirdupois (lb) metric ton (t) 1.102 ton, short [2,000 lb] metric ton (t) 0.9842 ton, long [2,240 lb] Application rate kilogram per hectare per year ([kg/ha]/yr) 0.8921 pound per acre per year ([lb/acre]/yr) Abbreviations AWQMN Ambient Water Quality Monitoring Network BBS block bootstrap CI confidence interval CQTC concentration-discharge trend component CRP Conservation Reserve Program CSP Conservation Security Program CWA Clean Water Act DP dissolved phosphorus EPA U.S. Environmental Protection Agency FN flow normalized HUC hydrologic unit code NO23 nitrate and nitrite PP particulate phosphorus QTC streamflow trend component TKN total Kjeldahl nitrogen TN total nitrogen TP total phosphorus TSS total suspended solids USGS U.S. Geological Survey Trends in Nutrient and Soil Loss in Illinois Rivers, 1978–2017 By Timothy O. Hodson and Paul J. Terrio Abstract Introduction Nutrient and soil loss, defined herein as the loss of Global population is projected to reach 9.8 billion by nutrients or soil to streams and other downstream receiving 2050 (United Nations, 2017). To feed this population, global waters, affect watersheds around the globe. Although agricultural production will need to increase by at least governments make large investments mitigating nutrient and 50 percent (Alexandratos and Bruinsma, 2012). The cost to soil loss through watershed management efforts, the efficacy society and the environment of such a dramatic increase is of these efforts is often difficult to assess, in part because far from certain, though it would be analogous, at least in streamflow variability obscures the effects. rate, to global trends in agricultural production during the late This study investigates the effects of watershed 20th century (Fuglie, 2010). management on nutrient and soil losses in the State of Illinois Increasing agricultural production is associated with during two periods: 1978 to 2017, and 2008 to 2017. The a variety of detrimental effects including habitat loss, former period provides an important test case for assessing increased greenhouse-gas emissions, soil erosion, and the efficacy of major Federal programs like the Clean Water nutrient pollution—defined as excess amounts of nitrogen Act and the Conservation Reserve Program at mitigating and phosphorus in aquatic systems (Brink and others, 1977; nutrient and soil loss, whereas the latter spans the years after Galloway and others, 2003; Montgomery, 2007; Reay and these policies were well established, thereby providing an others, 2012). Economic losses from soil erosion and nutrient assessment of whether these programs have kept pace with pollution already exceed tens of billions of dollars per year in ongoing trends in climate and watershed management. the United States and potentially hundreds of billions more The effect of interannual streamflow variability worldwide (Borrelli and others, 2017; Dodds and others, 2009; on long-term nutrient and soil loss trends was removed Eswaran and others, 2001; Noone and others, 2012). Although using an extension of the

Load more