Abstract
Slow-moving Hurricane Isaac affected the northern gulf coast between August 28th and August 31st, 2012. Previous studies of the event reported on the hydrometeorology of the event across southeast Louisiana and southern Mississippi. This report provides an in-depth examination and analysis of a suspected rainfall extreme in the New Orleans, Louisiana metropolitan area. Event analysis for most natural watersheds involves examination of river discharge data and the modeling of infiltration to infer watershed-average rainfall. New Orleans is unique because its topography does not allow for runoff, and rainfall must be pumped out of the city. A methodology is proposed which uses data from pumping records as a proxy for streamflow out of the New Orleans watershed. A hydrologic model was created to estimate runoff by modeling infiltration using the Green & Ampt method. Modeled runoff was compared to runoff inferred from pumping records to validate rainfall estimates. Modeled runoff was within 1% of the runoff inferred from pumping records; this strongly suggests that a relatively extreme amount of rain—exceeding the 100 year (1% annual chance) event—did occur over parts of New Orleans during Hurricane Isaac.
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Acknowledgments
The authors acknowledge the following individuals and organizations for supporting this work. Dr. Jeff Masters and Shaun Tanner from WeatherUnderground for helping obtain private weather station data; Daryl Herzmann and the Iowa Environmental Mesonet from Iowa State University for providing processed NMQ/Q2 radar precipitation data and daily NWS COOP observer reports; the New Orleans Sewerage and Water Board for providing access to city’s pumping records and daily rainfall data; and staff and management at the LMRFC for their support and inputs to this work.
Thank you to the journal editors and reviewers who volunteer their time. Their review and comments have helped to improve the quality of this article.
References
ArcGIS [Computer software]. Environmental Systems Research Institute, Redlands, CA.
Community Collaborative Rain, Hail and Snow Network. (2015). 〈www.cocorahs.org〉 (Feb. 10, 2015).
Green, W. H., and Ampt, G. A. (1911). “Studies on soil physics, 1, The flow of air and water through soils.” J. Agric. Sci., 4(1), 1–24.
Harris, A., and Hossain, F. (2008). “Investigating the optimal configuration of conceptual hydrologic models for satellite-rainfall-based flood prediction.” IEE Geosci. Remote Sens. Lett., 5(3), 532–536.
Interagency Performance Evaluation Task Force. (2006). “Performance evaluation of the New Orleans and southeast Louisiana Hurricane protection system.” U.S. Army Corps of Engineers, Washington, DC.
Knight, D. B., and Davis, R. E. (2009). “Contribution of tropical cyclones to extreme rainfall events in the southeastern United States.” J. Geophys. Res., 114(D23).
Lincoln, W. S., et al. (2013). “2012 southeast Louisiana and southern Mississippi flooding due to Hurricane Isaac.” National Weather Service, Slidell, LA.
National Weather Service. (2015). 〈water.weather.gov/precip/〉 (Feb. 10, 2015).
Sewerage and Water Board New Orleans. (2015). 〈gosserp.com〉 (Feb. 10, 2015).
U.S. Army Corps of Engineers Hydrologic Engineering Center. (2005). “Hydrologic modeling system (HEC-HMS) user’s manual, version 3.5.” Davis, CA.
Wundermap. (2015). 〈www.wunderground.com/wundermap/〉 (Feb. 10, 2015).
Information & Authors
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Published In
Journal of Hydrologic Engineering
Volume 21 • Issue 9 • September 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Apr 20, 2015
Accepted: Nov 4, 2015
Published online: May 6, 2016
Published in print: Sep 1, 2016
Discussion open until: Oct 6, 2016
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