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Flood forecasts are determined by examining past occurrences of flooding events, determining recurrence intervals of historical events, ... The extrapolations of recurrence intervals are then to forecast the future probability of a flood of a given discharge. The probability (P) of an flood with recurrence interval T is ;
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serc.carleton.edu/quantskills/methods/quantlit/floods.h...
serc.carleton.edu/quantskills/methods/quantlit/floods.html
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How is peak flow determined? ... Even though you may never have heard of "recurrence interval", it may be familiar to you. When a major flood occurs, you might have heard that the stream stage reached the "100-year flood level". This means that a flood of that magnitude has a 1 in 100 chance of occuring in any year.
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ga.water.usgs.gov/edu/qafloods.html
ga.water.usgs.gov/edu/qafloods.html
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Instead of the term "100-year flood" a hydrologist would rather describe this extreme hydrologic event as a flood having a 100-year recurrence interval.
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ga.water.usgs.gov/edu/100yearflood.html
ga.water.usgs.gov/edu/100yearflood.html
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Existing 50-, 100-, or 500-year recurrence interval flood flows are determined statistically for a specific site on a river, and serve as a planning tool for emergency response officials — they do not reflect actual forecast flood discharges.
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wa.water.usgs.gov/projects/pugethazards/urbanhaz/Mappin...
wa.water.usgs.gov/projects/pugethazards/urbanhaz/MappingNWS.htm
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The flood elevation profile (the elevation of the flood along the length of a stream) for the 100-year flood is determined using a hydraulic model.
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wa.water.usgs.gov/pubs/ofr/floodgis/
wa.water.usgs.gov/pubs/ofr/floodgis/
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Recurrence interval (R) for each flood is determined using the formula - R = (N + 1)/M. ... Therefore, if your R-value = 20, the recurrence interval would be referred to as a 20-year flood. But, if a 20-year flood did occur, don’t think it would be another 20 years before another flood that size would occur!
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wapi.isu.edu/envgeo/EG3_rivflood/eg3_rivers.htm
wapi.isu.edu/envgeo/EG3_rivflood/eg3_rivers.htm
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From this analysis a recurrence interval can be determined and a probability calculated for the likelihood of a given discharge in the stream for any year. The data needed to perform this ... From the best-fit line, one can determine the discharge associated with the a flood with a recurrence interval of say 10 years.
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www.tulane.edu/~sanelson/geol204/floodhaz.htm
www.tulane.edu/~sanelson/geol204/floodhaz.htm
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How is the recurrence interval for a flood determined? How may new data affect the flood-frequency curve? Floods have recurrence intervals, which means the time between each flood. ... The recurrence interval is determined by calculating the annual peak discharge, adding 1 to the number of years of record, and then dividing...
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www.associatedcontent.com/article/212307/floods.html?al...
www.associatedcontent.com/article/212307/floods.html?all=1
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Alaska snow and weather information ... When high water stages are determined from a flood frequency analysis, the impacts listed for the applicable stages will be the recurrence interval associated with that level and a qualifier to assess the quality of the recurrence interval estimate.
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aprfc.arh.noaa.gov/resources/docs/floodterms.php
aprfc.arh.noaa.gov/resources/docs/floodterms.php
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