Global Warming Effects Around the World

Indianapolis, IN, USA

Top Impact

Freshwater (Extreme wet)

Other Impacts

People (Health)

People (Costs)

Flood-related disaster

Flood–related disasters have become yearly events in Indiana. Sewage systems overflow, homes flood, belongings are destroyed, and the risks of intestinal illnesses rise among people exposed to contaminated floodwater.1

Key Facts

Indiana has seen severe flooding from heavy precipitation every year but one since 2001 (data available through 2011). That flooding has caused extensive property damage,2 including to two hospitals.3 Heavy rainfall and large amounts of runoff can overwhelm combined sewage and wastewater systems, sending untreated raw sewage mixed with storm water directly into area waterways.4 That increases the odds that people exposed to the water could contract severe diarrhea and other gastrointestinal illnesses.4,5,6

  • In Indianapolis, close to 8 billion gallons (30.3 billion liters) per year of combined sewage and storm water are dumped into local rivers and streams, primarily after it rains.7
  • Extreme rainfall events in the Midwest have been linked to an extremely concentrated flow of moist air in the atmosphere from the Gulf of Mexico and Caribbean Sea.8,9
  • More than half of all reported US outbreaks of waterborne disease from 1948–1994 occured after heavy precipitation events—storms that rank in the top 10 percent.4

Details

The Midwest faced more than a 30 percent increase in the number of very heavy rainfall events—storms with more than 4 inches (102 millimeters) of rain—during the twentieth century.10 Much of that increase occurred during the last three decades of that century.11 In a 2012 study, researchers from over 60 countries found rising evidence of human influence on the water cycle.12 For example, they noted that the warmer temperatures from increased levels of heat–trapping gases have led to an increase in humidity—as warmer air holds more moisture.13,14 More water in the atmosphere when storms pass through can lead to heavier rainfall.

In Indiana, the federal government has declared a disaster area stemming from severe storms or flooding every year but one between 2001 and 2011.2 In 2008, large portions of the state received more than 12 inches (305 millimeters) of rain in June. Martinsville, just south of Indianapolis, received more than 20 inches (500 millimeters) of rain that month.15 Federal officials declared 39 counties disaster areas. Two hospitals had to be evacuated because of extensive flood damage, thousands of homes and businesses were damaged, and some 1.4 million acres (5,600 square kilometers) of farmland had to be rehabilitated.3

In April 2011, flooding occurred again when southern Indiana received 5 to 8 inches (127 to 203 millimeters) more rain than normal for the month, with heavy rains continuing through May and June in some areas.16 Then, in July, central Indiana had up to 8 inches (203 millimeters) less rain than normal for that month.17 A more extreme water cycle—with intense rain and then dry periods—is an example of what meteorologists have already observed as the climate changes.18 They expect this trend to continue as the climate changes further.18

Across Indiana, more than 100 communities have combined sewage19 and storm water systems, which on average days can treat all sewage and storm water drainage. However, heavy rainfall or snowmelt can exceed the capacity of the systems, which are designed to discharge excess sewage and storm water directly into local waterways.

In Indianapolis, close to 8 billion gallons (30.3 billion liters) per year of combined sewage and storm water are dumped into local rivers and streams, primarily after it rains.7 Because of this problem, the city has agreed to upgrade its sewer and storm water system and expand its capacity.7

Combined sewage and storm water may overflow into nearby rivers and streams when Indianapolis receives as little as a quarter–inch of rain.7 The city's long–term plans call for reducing these overflows from 45 to 80 events a year to 2 to 4. However, engineers used historical averages from 1950 to 2003 to design the new system,20 noting that actual overflows would depend on the weather each year.7 Because extreme rain has already become more likely given climate change,11 will the new system be large enough?

Milwaukee has already made similar upgrades to its sewer and storm water system, but has found that it cannot handle very heavy precipitation. In 2008, for example, more than 3.5 billion gallons (13.2 billion liters) of sewage and storm water flowed directly into Lake Michigan from the Milwaukee system after heavy rain.21

Such contaminated water can contain more than 100 types of pathogenic bacteria, viruses, and parasites, which can cause many types of gastrointestinal diseases, including nausea, vomiting, and acute diarrhea.22 Many studies have shown the connections between flooding and disease.

For example, in one study of reported US outbreaks of waterborne disease over 45 years, researchers found that more than half occurred after heavy precipitation events—those that ranked in the top 10 percent.4

In a study at a children's hospital in southeastern Wisconsin, doctors found an 11 percent increase in emergency department visits by children because of gastrointestinal illness after rainfall.6 That rainfall ranged from 0.01 to 2.76 inches (0.2 to 70.1 millimeters), with a median of 0.23 inch (5.8 millimeters).6 The doctors recommended better monitoring of water quality, improved sewage control, and boil water alerts when necessary.6

The turbidity—or cloudiness—of water usually increases during heavy storms. Studies in Milwaukee, Philadelphia, and Atlanta have shown a relationship between greater turbidity and gastrointestinal illness.23,24,25

Part of a Larger Pattern

Where does all that rain come from? Spring downpours and flooding in the Midwest, including the Ohio River Valley, fit the pattern of an extremely concentrated flow of moist air in the atmosphere.8,9Such a pattern occurs when warm, moist air from the Caribbean and the Gulf of Mexico moves north into the Great Plains jet. When that warm, moist air meets cold air from the north, extreme storms occur.

Meteorologists have observed this pattern during large–scale flooding in the Midwest in late spring and summer in 1993, 2008, 2010, and 2011.26,27,8,9 That is, rising water temperatures in the Caribbean28 can affect weather in the Midwest.8

What the Future Holds

When researchers took a closer look at how climate may change in the Midwest, they found that annual precipitation might rise 10 to 15 percent by the end of this century, compared with amounts at the end of the twentieth century.29 Seasonal distribution of the water really matters. Winter and spring could bring much higher precipitation, while summer is likely to see less rainfall than in the past. Spring precipitation may increase 25 to 30 percent, for example, depending on the amount of heat trapping emissions we release into the atmosphere.29

That annual precipitation amount is also more likely to come in the form of heavy rain, or in other words, dry periods punctuated by torrential rain or heavy snowfall. In Indianapolis, the amount of precipitation within a 24–hour period could rise by about 30 percent by the end of this century.29

Both the timing and the amount of rainfall affect the risk of flooding. If an area receives 10 inches of rain in the course of a spring, that may be fine. However, if those 10 inches fall during just a few days, the area may be in trouble. Not all watersheds are the same, and heavy rainfall does not always translate into flooding. However, climate change is increasing the risks of flooding from extreme rainfall in areas such as Indiana and the Ohio River Valley.30

Studies of precipitation extremes help engineers who design buildings, bridges, and sewage systems determine the needed capacity, height, and strength. Frequent extremes pose a greater concern than those that occur less often.

We must adapt to the fact that very heavy rain or snow events are becoming more common. Clearly, the time has come to develop smart planning and engineering solutions to cope with extreme events.

At the same time, we must reduce our heat trapping emissions and develop energy sources and transportation methods that do not rely on fossil fuels—to help avoid even larger increases in heavy rain that could cause damaging flooding and waterborne diseases.

Credits

Endnotes

  1. Photograph used with permission of Mandie Bailey. Online at http://www.flickr.com/photos/26406090@N05/2560370974/. Accessed August 23, 2012.
  2. Federal Emergency Management Agency. 2011. Disaster search: Indiana–Disaster type: Any. Washington, DC. Online at http://www.fema.gov/femaNews/disasterSearch.do?action=Main.
  3. Morlock, S.E., C.D. Menke, D.V. Arvin, and M.H. Kim. 2009. Flood of June 7–9, 2008, in Central and Southern Indiana. Open File Report 2008–1322. Reston, VA: U.S. Geological Survey. Online at http://pubs.usgs.gov/of/2008/1322/.
  4. Curriero, F.C., J.A. Patz, J.B. Rose, and S.Lele. 2001. The association between extreme precipitation and waterborne disease outbreaks in the United States, 1948–1994. American Journal of Public Health 91(8):1194–1199. Online at http://www.ncbi.nlm.nih.gov/pubmed/11499103.
  5. Atherholt, T.B., M.W. LeChevallier, W.D. Norton, and J.S. Rosen. 1998. Effect of rainfall on giardia and cryptosporidium. Journal of the American Water Works Association 90(9):66–88. Online at http://www.mendeley.com/research/effect-of-rainfall-on-giardia-and-cryptosporidium/.
  6. Drayna, P., et al. 2010. Association between rainfall and pediatric emergency department visits for acute gastrointestinal illness. Environmental Health Perspectives 118(10):1439–1443; doi:10.1289/ehp.0901671. Online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957926/?tool=pubmed.
  7. Citizens Energy Group. 2011. Combined sewer overflow. Indianapolis, IN: Online at http://www.citizensenergygroup.com/Wastewater/CSO.aspx.
  8. Dirmeyer, P.A., and J.L. Kinter. 2010: Floods over the U.S. Midwest: A regional water cycle perspective. Journal of Hydrometeorology 11:1172–1181; doi:10.1175/2010JHM1196.1. Online at http://journals.ametsoc.org/doi/abs/10.1175/2010JHM1196.1.
  9. National Climatic Data Center. 2011. Spring 2011 U.S. climate extremes. National Oceanic and Atmospheric Administration. Silver Spring, MD. Online at http://www.ncdc.noaa.gov/special-reports/2011-spring-extremes/.
  10. Groisman, P.Y., R.W. Knight, and T.R. Karl. 2001. Heavy precipitation and high streamflow in the contiguous United States: Trends in the twentieth century. Bulletin of the American Meteorological Society 82:219–246; doi:10.1175/1520–0477(2001)082<0219:HPAHSI>2.3.CO;2. Online at http://journals.ametsoc.org/doi/abs/10.1175/1520-0477%282001%29082%3C0219%3AHPAHSI%3E2.3.CO%3B2.
  11. Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore. 2004. Contemporary changes of the hydrological cycle over the contiguous United States: Trends derived from in situ observations. Journal of Hydrometeorology 5:64–85; doi:10.1175/1525–7541(2004)005<0064:CCOTHC>2.0.CO;2. Online at http://journals.ametsoc.org/doi/abs/10.1175/1525-7541%282004%29005%3C0064%3ACCOTHC%3E2.0.CO%3B2.
  12. Intergovernmental Panel on Climate Change. 2012. Managing the risks of extreme events and disasters to advance climate change adaptation (SREX). A special report of Working Groups I and II of the Intergovernmental Panel on Climate Change. C.B. Field, V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.–K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley, eds. Cambridge, UK, and New York, NY: Cambridge University Press. Online at http://ipcc-wg2.gov/SREX/.
  13. Santer, B.D., et al. 2007. Identification of human-induced changes in atmospheric moisture content. Proceedings of the National Academy of Sciences; doi:10.1073/pnas.0702872104. Online at http://www.pnas.org/content/104/39/15248. As cited in: Intergovernmental Panel on Climate Change. 2012. Managing the risks of extreme events and disasters to advance climate change adaptation (SREX). A special report of Working Groups I and II of the Intergovernmental Panel on Climate Change. C.B. Field, V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley, eds. Cambridge, UK, and New York, NY: Cambridge University Press. Online at http://ipcc-wg2.gov/SREX/.
  14. Willett, K.M., N.P. Gillett, P.D. Jones, and P.W. Thorne. 2007. Attribution of observed surface humidity changes to human influence. Nature, 449:710–712; doi:10.1038/nature06207. Online at http://www.nature.com/nature/journal/v449/n7163/abs/nature06207.html. As cited in: Intergovernmental Panel on Climate Change. 2012. Managing the risks of extreme events and disasters to advance climate change adaptation (SREX). A special report of Working Groups I and II of the Intergovernmental Panel on Climate Change. C.B. Field, V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.–K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley, eds. Cambridge, UK, and New York, NY: Cambridge University Press. Online at http://ipcc-wg2.gov/SREX/.
  15. National Climatic Data Center. 2008 Midwestern U.S. floods. National Oceanic and Atmospheric Administration. Asheville, NC. Online at http://www.ncdc.noaa.gov/special-reports/2008-floods.html.
  16. National Weather Service, Advanced Hydrologic Prediction Service. 2011. Archive April, May, and June 2011: Departure from normal precipitation, Indiana. Silver Spring, MD. National Oceanic and Atmospheric Administration. Online at http://water.weather.gov/precip/.
  17. National Weather Service, Advanced Hydrologic Prediction Service. 2011. Archive July 2011: Departure from normal precipitation, Indiana. Silver Spring, MD. National Oceanic and Atmospheric Administration. Online at http://water.weather.gov/precip/.
  18. harin, V.V., and F.W. Zwiers. 2000. Changes in the extremes in an ensemble of transient climate simulations with a coupled atmosphere–ocean GCM. Journal of Climate 13:3760–3788; doi:10.1175/1520-0442(2000)013<3760:CITEIA>2.0.CO;2. Online at http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%282000%29013%3C3760%3ACITEIA%3E2.0.CO%3B2.
  19. Indiana Department of Environmental Management. 2005. Indiana's approach to combined sewer overflow compliance: Workplan for CSO long term control plan review and implementation. Indianapolis, IN. Online at http://www.in.gov/idem/files/cso_workplan.pdf.
  20. Indianapolis Department of Public Works. 2006. Raw sewage overflow long term control plan and water quality improvement report. Indianapolis, IN. Online at http://www.citizensenergygroup.com/Wastewater/LongTermControlPlan.aspx.
  21. Milwaukee Metropolitan Sewerage District. 2008. Storm update. June 20. Online at http://v3.mmsd.com/NewsArchives.aspx.
  22. Rose, J.B., P.R. Epstein, E.K. Lipp, B.H. Sherman, S.M. Bernard, and J.A. Patz. 2001. Climate variability and change in the United States: Potential impacts on water– and foodborne diseases caused by microbiologic agents. Environmental Health Perspectives 109(Supplement 2):211–221. Online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240668/pdf/ehp109s-000211.pdf.
  23. Morris, R.D., E.N. Naumova, R. Levin, and R.L. Munasinghe. 1996. Temporal variation in drinking water turbidity and diagnosed gastroenteritis in Milwaukee. American Journal of Public Health 86(2). Online at http://ajph.aphapublications.org/cgi/content/abstract/86/2/237.
  24. Schwartz J., R. Levin, and K. Hodge. 1997. Drinking water turbidity and pediatric hospital use for gastrointestinal illness in Philadelphia. Epidemiology 8(6):615–620. Online at http://www.ncbi.nlm.nih.gov/pubmed/9345659.
  25. Tinker, S.C., Tinker, S.C., C.L Moe, M. Klein, W.D. Flanders, J. Uber, A. Amirtharajah, P. Singer, and P.E. Tolbert. 2010. Drinking water turbidity and emergency department visits for gastrointestinal illness in Atlanta, 1993–2004. Journal of Exposure Science and Environmental Epidemiology 20(1):19–28; doi:10.1038/jes.2008.68. Online at http://www.nature.com/jes/journal/v20/n1/abs/jes200868a.html.
  26. Dirmeyer, P.A., and K.L. Brubaker. 1999. Contrasting evaporative moisture sources during the drought of 1988 and the flood of 1993. Journal of Geophysical Research 104(19):383–19,397. Online at http://www.agu.org/pubs/crossref/1999/1999JD900222.shtml.
  27. Dirmeyer, P.A., and J.L. Kinter III. 2009. The Maya: Late spring floods in the U.S. Midwest. Eos, Transactions, American Geophysical Union 90:101–102. Cited in: P.A. Dirmeyer and J.L. Kinter III. 2010. Floods over the U.S. Midwest: A regional water cycle perspective. Journal of Hydrometeorology 11:1172–1181; doi:10.1175/2010JHM1196.1 Online at http://journals.ametsoc.org/doi/abs/10.1175/2010JHM1196.1.
  28. Jury, M. 2011. Long–term variability and trends in the Caribbean Sea. International Journal of Oceanography. Article ID 465810; doi:10.1155/2011/465810. Online at http://www.hindawi.com/journals/ijog/2011/465810/.
  29. Hayhoe, K., J. VanDorn, V. Naik, and D. Wuebbles. 2009. Climate change in the Midwest projections of future temperature and precipitation. Cambridge, MA: Union of Concerned Scientists. Online at http://www.ucsusa.org/assets/documents/global_warming/midwest-climate-impacts.pdf.
  30. Hirsch, R.M., and K.R. Ryberg. 2012. Has the magnitude of floods across the USA changed with global CO2 levels? Hydrological Sciences Journal 57(1)1–9; doi:10.1080/02626667.2011.621895. Online at http://www.tandfonline.com/doi/abs/10.1080/02626667.2011.621895.
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