Alaska Section, AWRA, NorthernRegion BrownBag Meetings
December 29, 2017 Do the 2016 USGS FloodPeak Regression Equations Systematically Over or UnderEstimate FloodPeak Discharge? James W. Aldrich, P.H., P.E.,
Arctic Hydrologic Consultants, Fairbanks, Alaska For more than 40 years, the USGS floodpeak regression equations have been used to design bridges, culverts and flood control measures at ungaged sites throughout Alaska. Updated approximately every 10 years, as our floodpeak database increased, the equations have provided an increasingly more accurate method of estimating floodpeak magnitude and frequency at ungaged sites. Although the equations are easy to use, there are important concepts that the users should understand regarding the development of the equations. Additionally, in 2016 a significantly different approach was taken in the development of the equations. This presentation will discuss some of the basic concepts that users of the regression equations should understand as well as present the results from a test of the new equations to determine if they systematically over or underestimate floodpeak discharge. Select Presentation Figures Figure 1. 2016 USGS Regression Equations Figure 2. Use of the 2016 USGS Regression Equations on the North Slope, Former Region 7 Figure 3. What Options are Available for Region 7? 2003 USGS Regression Equations? Figure 4. 50Year Flood Peaks Predicted with 2016 USGS Equations
