Estimation of peak discharge quantiles for selected annual exceedance probabilities in Northeastern Illinois.

Details

• Creators:
  Over, Thomas M. ; Saito, Riki ; Veilleux, Andrea G. ; Sharpe, Jennifer ; Soong, David ; Ishii, Audrey
• Corporate Creators:
  Geological Survey (U.S.) ; United States. Department of the Interior
• Corporate Contributors:
  Illinois. Department of Transportation. Bureau of Materials and Physical Research ; United States. Federal Highway Administration
• Subject/TRT Terms:
  Drainage Basins Flood Frequency Floods Land Use Peak Discharge Peak Discharge Estimation Regionalization Regression Analysis Spatial Analysis Streamflow Streamflow Statistics StreamStats Urbanization Web Applications

  More +
• Publication/ Report Number:
  FHWA-ICT-16-013
• Resource Type:
  Tech Report
• Geographical Coverage:
  Illinois ; United States
• Corporate Publisher:
  Illinois Center for Transportation
• Abstract:
  This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10,
  
  0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based
  
  on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set of equations was developed through a
  
  temporal analysis with a two-step least squares-quantile regression technique that measures the average effect of changes in the urbanization
  
  of the watersheds used in the study. The resulting equations can be used to adjust rural peak discharge quantiles for the effect of urbanization,
  
  and in this study the equations also were used to adjust the annual maximum peak discharges from the study watersheds to 2010 urbanization
  
  conditions.
  
  The other set of equations was developed by a spatial analysis. This analysis used generalized least-squares regression to fit the peak discharge
  
  quantiles computed from the urbanization-adjusted annual maximum peak discharges from the study watersheds to drainage-basin
  
  characteristics. The peak discharge quantiles were computed by using the Expected Moments Algorithm following the removal of potentially
  
  influential low floods defined by a multiple Grubbs-Beck test. To improve the quantile estimates, generalized skew coefficients were obtained
  
  from a newly developed regional skew model in which the skew increases with the urbanized land use fraction. The drainage-basin
  
  characteristics used as explanatory variables in the spatial analysis include drainage area, the fraction of developed land, the fraction of land
  
  with poorly drained soils or likely water, and the basin slope estimated as the ratio of the basin relief to basin perimeter.
  
  This report also provides: (1) examples to illustrate the use of the spatial and urbanization-adjustment equations for estimating peak discharge
  
  quantiles at ungaged sites and to improve flood-quantile estimates at and near a gaged site; (2) the urbanization-adjusted annual maximum
  
  peak discharges and peak discharge quantile estimates at streamgages from 181 watersheds including the 117 study watersheds and 64
  
  additional watersheds in the study region that were originally considered for use in the study but later deemed to be redundant.
  
  The urbanization-adjustment equations, spatial regression equations, and peak discharge quantile estimates developed in this study will be
  
  made available in the web-based application StreamStats, which provides automated regression-equation solutions for user-selected stream
  
  locations. Figures and tables comparing the observed and urbanization-adjusted peak discharge records by streamgage are provided at
  
  http://dx.doi.org/10.3133/sir20165050 for download.
  
  
• Format:
  PDF
• Funding:
  R27-144
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:c2d6fba6a5d949169791c833603054f4afbcb74799c059b561efe001856453bd
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31071/dot_31071_DS1.pdf
• File Type:
  [PDF - 7.57 MB ]