1. The term “100-year storm” refers to a theoretical event known as the 1% annual exceedance probability (AEP) storm. The 1% AEP storm is severe enough that it has a 1% chance of being equaled or exceeded in any given year and therefore an average recurrence interval of 100 years according to the U.S. Geological Survey.
2. A 25-year storm has a 4% chance of being equaled or exceeded in any given year and therefore an average recurrence interval of 25 years.
3. ICLR. CAT Hotsheet. August 19 Ontario Storm aka “Freaky Friday.” Toronto Ontario:Institute for Catastrophic Loss Reduction (19 Aug 2005). Available: http://www.iclr.org/images/Hotsheet_August_19_storm.pdf [accessed 15 Nov 2011].
4. NACWA AMWA. Confronting Climate Change: An Early Analysis of Water and Wastewater Adaptation Costs. Englewood CO:CH2M HILL Inc. (2009). Available: http://www.nacwa.org/images/stories/public/2009-10-28ccreport.pdf [accessed 15 Nov 2011].
5. NDWAC. Climate Ready Water Utilities. Final Report of the National Drinking Water Advisory Council. Washington DC:National Drinking Water Advisory Council (2010). Available: http://water.epa.gov/drink/ndwac/climatechange/upload/CRWU-NDWAC-Final-Report-12-09-10-2.pdf [accessed 15 Nov 2011].