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Unformatted text preview: Virginia Tech Department of Civil and Environmental Engineering CEE 5734 Urban Hydrology and Stormwater Management Homework #1: Introduction to the Rational Method Solutions 1. Compare/contrast average recurrence interval (ARI) and annual exceedance probability (AEP). 1. Describe each briefly with an emphasis on both similarities and differences between the two perspectives. Response: I have excerpted from the NOAA documentation - see next page. This describes the differences between these two perspectives and what each perspective entails. b. For the Blacksburg location, plot both ARI and AEP IDF curves for all durations up to 1 day for all return periods reported. c. Use the graphs created in Problem 1b to address how ARI and AEP differ Response to parts b and c: Plots are shown on the following pages. Differences are so small as to be impossible to see. A spreadsheet differencing (ARI-AEP) was created (see table following). Note that (ARI-AEP) !0 for all durations and return periods meaning that ARI is always greater than or equal to AEP for a given return period and duration. Differences are greatest for smaller return periods and for shorter durations. Excerpt below taken from: http://www.nws.noaa.gov/oh/hdsc/PF_documents/Atlas14_Volume2.pdf 3.2. Terminology; Partial Duration and Annual Maximum Series This publication adopts the terminology average recurrence interval (ARI) and annual exceedance probability (AEP) presented in Australian Rainfall and Runoff (Institute of Engineers, Australia, 1987) which in turn is based on Laurenson (1987). NOAA Atlas 14 is based on the analysis of annual maximum series data with the results converted to represent estimates based on partial duration series. The results for these two types of series differ at shorter average recurrence intervals and have different meanings. for these two types of series differ at shorter average recurrence intervals and have different meanings....
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This note was uploaded on 12/24/2011 for the course CEE 5734 taught by Professor Moglen during the Spring '11 term at Virginia Tech.
- Spring '11