Observed and urbanization-adjusted annual maximum peak discharge and associated urban fraction and precipitation values at USGS streamgage:
05530480 WILLOW CREEK AT ORCHARD PLACE, IL

Observed annual peak-flood magnitudes were adjusted to 2010 land-use conditions on the basis of panel data regression model with fixed effect analysis. The symbols presented in the figure are: "observed annual peaks", "adjusted annual peaks", and "fraction of urbanization in the watershed"

Legend for Graph

Water year Segment Discharge code Cumulative reservoir storage (acre-feet) Urban fraction Precipitation (inches) Observed peak discharge (ft3/s) Adjusted peak discharge (ft3/s) Exceedance probability
1955 1 7 0 0.156 3.790 782 1380 0.074
1957 1 7 0 0.186 3.379 1200 1920 0.020
1961 1 -- 0 0.254 2.033 322 619 0.656
1962 1 -- 0 0.277 0.180 310 591 0.698
1963 1 -- 0 0.299 1.605 126 317 0.958
1964 1 -- 0 0.322 1.141 210 433 0.886
1965 1 -- 0 0.345 0.185 184 390 0.925
1966 1 -- 0 0.368 2.173 692 1030 0.193
1967 1 -- 0 0.391 2.459 2100 2800 0.007
1968 1 -- 0 0.413 2.564 340 558 0.745
1969 1 -- 0 0.436 1.416 494 740 0.494
1970 1 -- 0 0.459 1.259 845 1150 0.143
1971 1 -- 0 0.481 1.616 366 551 0.752
1972 1 -- 0 0.504 1.830 1350 1710 0.034
1973 1 -- 0 0.526 0.899 718 936 0.265
1974 1 -- 0 0.548 0.791 494 661 0.601
1975 1 2 0 0.571 1.559 1070 1310 0.088
1976 1 -- 0 0.593 1.227 754 922 0.277
1977 1 -- 0 0.615 1.213 426 541 0.764
1978 1 -- 0 0.638 2.303 1680 1900 0.023
1979 1 -- 0 0.660 1.358 1010 1150 0.147