Scientific Investigations Report 2013–5187
AbstractThe U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency, determined annual exceedance probabilities for peak discharges occurring during the 2011 water year (October 1 to September 30) at streamgages in Vermont and selected streamgages in New Hampshire, western Massachusetts, and northeastern New York. This report presents the 2011 water year peak discharges at 145 streamgages in the study area and provides the results of the analyses of the 50-, 20-, 10-, 4-, 2-, 1-, and 0.2-percent annual exceedance probability discharges at 135 of the 145 streamgages. The annual exceedance probabilities for the 2011 water year peak discharges also are presented. Snowmelt and near record rainfall led to flooding across northern Vermont on April 27 and 28, 2011. At three streamgages with more than 10 years of record, the April rain event resulted in the peak discharge of record. At seven streamgages, the peak discharge resulting from this event had an annual exceedance probability less than or equal to 1 percent. In early May 2011, new peak stage records were set at two Lake Champlain gages with more than 100 years of record. At the Lake Champlain at Burlington, Vermont, gage, the water surface reached 102.79 feet (ft) (North American Vertical Datum of 1988 (NAVD 88)) on May 6, 2011, and at the Richelieu River (Lake Champlain) at Rouses Point, New York, gage, the water surface reached 102.75 ft NAVD 88. Record-breaking rainfall in late May produced additional flooding across northern Vermont on May 26 and 27, 2011. Four streamgages in northwestern Vermont recorded peak-of-record discharges as a result of this flooding. At three streamgages, the peak discharges from this event had an annual exceedance probability less than or equal to 1 percent. From August 28 to 29, 2011, Tropical Storm Irene delivered rainfall totals ranging from about 3 to more than 10 inches, which resulted in extensive flooding and new period-of-record peak discharges at 37 streamgages in the study area. The peak discharges as a result of Tropical Storm Irene had an annual exceedance probability of less than or equal to 1 percent at 36 streamgages. At 11 of these 36 streamgages, the annual exceedance probability of the peak discharges was less than or equal to 0.2 percent. |
First posted December 3, 2013
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Olson, S.A., and Bent, G.C., 2013, Annual exceedance probabilities of the peak discharges of 2011 at streamgages in Vermont and selected streamgages in New Hampshire, western Massachusetts, and northeastern New York: U.S. Geological Survey Scientific Investigations Report 2013–5187, 17 p., http://dx.doi.org/10.3133/sir20135187.
ISSN 2328-0328 (online)
Abstract
Introduction
Peak Discharge and Lake Elevation Data for Water Year 2011
Frequency Analyses
Lake Champlain Peak Elevations and Frequency Analyses
Summary
Selected References
Appendix 1. Location Descriptions of Streamgages and Lake Gages Used to Characterize 2011 Flooding in Vermont, Northern New Hampshire, Western Massachusetts, and Northeastern New York
Appendix 2. Peak Discharge or Stage Occurring in 2011 at Streamgages or Lake Gages Used to Characterize 2011 Flooding in Vermont, Northern New Hampshire, Western Massachusetts, and Northeastern New York
Appendix 3. Discharges for Selected Annual Exceedance Probabilities at Streamgages Used to Characterize Flooding in 2011 in Vermont, Northern New Hampshire, Western Massachusetts, and Northeastern New York