Frequency Analysis”
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OFFICE OF PUBLIC WORKS FLOOD STUDIES UPDATE PROGRAMME WORK-PACKAGE WP-2.2 “FREQUENCY ANALYSIS” Appendix 4 Department of Engineering Hydrology & The Environmental Change Institute National University of Ireland, Galway September 2009 Appendix 4A1 6011 RIVER FANE @ MOYLES MILL Annual Maximum Floods 1957 to 2004.(no missing years) A1 A (km 2)= 234.00 N= 48 Year AMF(m 3 /s) Moments PWM L-Moments 1957 12.34 Mean 15.856 M100 15.856 L1 15.856 L-Cv 0.113 1958 21.07 Median 15.390 M110 8.825 L2 1.795 L-Skew 0.089 1959 15.39 Std.Dev. 3.195 M120 6.210 L3 0.161 L-Kur 0.074 1960 14.20 CV 0.202 M130 4.819 L4 0.134 1961 15.70 HazenS. 0.812 1962 13.39 30 1963 18.84 6011 RIVER FANE @ MOYLES MILL 1964 19.49 EV1 25 1965 18.14 1966 18.84 20 1967 13.39 winter peak 1968 15.39 15 1969 13.56 1970 10.94 AMF(m3/s) 10 1971 13.39 1972 10.90 1973 13.31 5 2 5 10 25 50 100 500 1974 14.37 1975 11.29 0 EV1 y 1976 19.13 -2-1 0 1 2 3 4 5 6 7 1977 11.68 30 1978 26.36 LO2 1979 16.91 25 1980 17.14 1981 17.04 20 1982 17.04 1983 19.35 15 1984 11.98 AMF(m3/s) 1985 12.49 10 1986 14.20 FANE CATCHMENT 1987 15.16 5 1988 15.45 2 5 10 25 50 100 500 1989 12.74 0 1990 14.88 -6 -4 -2 0 2 4 6 8 1991 19.03 Logistic reduced variate 1992 12.87 1.5 1993 14.88 LogNormal 1994 16.89 1.4 1995 19.99 1996 15.16 1.3 1997 15.73 1998 14.88 1.2 1999 17.49 1.1 2000 19.51 log10(AMF) 2001 19.35 1 2002 19.67 2003 11.98 0.9 2004 18.10 2 5 10 25 50 100 500 0.8 -3 -2 -1 0 1 2 3 4 Normal N(0,1) y COMMENTS 1. Medium skewness 2. No summer peak was observed in the AM series 3.Linear Score (subjective) :EV1=4, LO2=2, LN2=3 *For Explanation of Scores and Codes see in Introductory Page 4.Shape Codes (subjective) :EV1=L2, LO2=U1, LN2=L2 6013 RIVER DEE @ CHARLEVILLE WEIR Annual Maximum Floods 1975 to 2004.(no missing years) A1 A (km 2)= 307.00 N= 30 Year AMF(m 3 /s) Moments PWM L-Moments 1975 18.07 Mean 27.808 M100 27.808 L1 27.808 L-Cv 0.157 1976 20.36 Median 27.365 M110 16.090 L2 4.372 L-Skew 0.019 1977 15.76 Std.Dev. 7.475 M120 11.469 L3 0.084 L-Kur 0.012 1978 40.00 CV 0.269 M130 8.943 L4 0.052 1979 37.70 HazenS. 0.100 1980 37.20 45 1981 35.23 6013 RIVER DEE @ CHARLEVILLE WEIR 1982 24.18 40 EV1 1983 29.43 35 1984 33.78 30 winter peak 1985 22.80 summer peak 1986 19.64 25 1987 26.84 20 1988 18.76 AMF(m3/s) 15 1989 32.61 1990 30.09 10 1991 27.05 5 2 5 10 25 50 100 500 1992 21.10 1993 35.71 0 EV1 y 1994 29.65 -2-1 0 1 2 3 4 5 6 7 1995 41.84 45 1996 22.61 LO2 40 1997 34.26 1998 27.47 35 1999 18.58 30 2000 34.74 25 2001 23.38 2002 31.91 20 AMF(m3/s) 2003 16.24 15 2004 27.26 10 5 2 5 10 25 50 100 500 0 GLYDE & DEE CATCHMENT -6 -4 -2 0 2 4 6 8 Logistic reduced variate 1.7 LogNormal 1.6 1.5 1.4 1.3 1.2 log10(AMF) 1.1 1 0.9 2 5 10 25 50 100 500 0.8 -3 -2 -1 0 1 2 3 4 Normal N(0,1) y COMMENTS 1. Low positive skewness 2. The 4th highest peak comes out as a summer peak 3.Linear Score(subjective):EV1=2, LO2=3, LN2=4 *For Explanation of Scores and Codes see in Introductory Page 4.Shape Codes(subjective):EV1=D1, LO2=S1, LN2=L2 6014 RIVER GLYDE @ TALLANSTOWN Annual Maximum Floods 1975 to 2004.(no missing years) A1 A (km 2)= 270.00 N= 30 Year AMF(m 3 /s) Moments PWM L-Moments 1975 15.49 Mean 22.557 M100 22.557 L1 22.557 L-Cv 0.149 1976 19.86 Median 21.460 M110 12.956 L2 3.355 L-Skew 0.224 1977 15.30 Std.Dev. 6.045 M120 9.321 L3 0.751 L-Kur 0.121 1978 39.40 CV 0.268 M130 7.357 L4 0.406 1979 24.64 HazenS. 1.306 1980 24.13 45 1981 32.39 6014 RIVER GLYDE @ TALLANSTOWN 1982 23.63 40 EV1 1983 30.62 35 1984 30.62 winter peak 30 1985 17.70 summer peak 1986 18.54 25 1987 21.23 20 1988 16.87 AMF(m3/s) 15 1989 25.15 1990 25.15 10 2 5 10 25 50 100 500 1991 17.70 5 1992 16.97 1993 28.63 0 EV1 y 1994 22.65 -2-1 0 1 2 3 4 5 6 7 1995 33.30 45 1996 21.84 LO2 40 1997 19.46 1998 15.30 35 1999 19.86 30 2000 23.63 25 2001 20.76 2002 18.12 20 AMF(m3/s) 2003 16.07 15 2004 21.69 10 2 5 10 25 50 100 500 5 0 GLYDE & DEE CATCHMENT &DEE GLYDE -6 -4 -2 0 2 4 6 8 Logistic reduced variate 1.7 LogNormal 1.6 1.5 1.4 1.3 1.2 log10(AMF) 1.1 1 0.9 2 5 10 25 50 100 500 0.8 -3 -2 -1 0 1 2 3 4 Normal N(0,1) y COMMENTS 1.Linear Score (subjective) :EV1=4, LO2=2, LN2=3 2.Shape Codes (subjective) :EV1=L1, LO2=U1, LN2=L2 *For Explanation of Scores and Codes see in Introductory Page 6025 RIVER DEE @ BURLEY BRIDGE Annual Maximum Floods 1975 to 2004.(no missing years) A1 A (km 2)= 176.00 N= 30 Year AMF(m 3 /s) Moments PWM L-Moments 1975 12.53 Mean 18.322 M100 18.322 L1 18.322 L-Cv 0.088 1976 16.66 Median 18.690 M110 9.968 L2 1.614 L-Skew -0.071 1977 12.80 Std.Dev. 2.854 M120 6.895 L3 -0.114 L-Kur 0.185 1978 20.04 CV 0.156 M130 5.293 L4 0.299 1979 20.49 HazenS. -0.331 1980 18.21 30 1981 17.90 6025 RIVER DEE @ BURLEY BRIDGE 1982 16.86 EV1 25 1983 18.74 1984 18.53 20 1985 18.64 1986 13.91 winter peak 15 1987 19.28 summer peak 1988 17.69 AMF(m3/s) 10 1989 19.06 1990 19.06 1991 19.72 5 2 5 10 25 50 100 500 1992 14.97 1993 18.96 0 EV1 y 1994 19.17 -2-1 0 1 2 3 4 5 6 7 1995 23.46 30 1996 18.64 LO2 1997 16.76 25 1998 21.04 1999 14.68 20 2000 23.57 2001 19.61 15 2002 22.76 AMF(m3/s) 2003 14.48 10 2004 21.44 5 2 5 10 25 50 100 500 0 GLYDE & DEE CATCHMENT &GLYDEDEE -6 -4 -2 0 2 4 6 8 Logistic reduced variate 1.5 LogNormal 1.4 1.3 1.2 1.1 log10(AMF) 1 0.9 2 5 10 25 50 100 500 0.8 -3 -2 -1 0 1 2 3 4 Normal N(0,1) y COMMENTS 1.Negative skewness 2.Linear Score (subjective) :EV1=2, LO2=4, LN2=3 3.Shape Codes (subjective) :EV1=D1, LO2=L2, LN2=S1 *For Explanation of Scores and Codes see in Introductory Page 6026 RIVER GLYDE @ ACLINT BRIDGE Annual Maximum Floods 1959 to 2004.(no missing years) A1 A (km 2)= 144.00 N= 46 Year AMF(m 3 /s) Moments PWM L-Moments 1959 12.30 Mean 13.867 M100 13.867 L1 13.867 L-Cv 0.177 1960 23.89 Median 12.297 M110 8.161 L2 2.456 L-Skew 0.240 1961 10.99 Std.Dev. 4.434 M120 5.949 L3 0.590 L-Kur 0.092 1962 12.30 CV 0.320 M130 4.731 L4 0.227 1963 15.50 HazenS. 1.051 1964 24.12 30 1965 18.61 6026 RIVER GLYDE @ ACLINT BRIDGE 1966 15.50 EV1 25 1967 22.99 1968 20.21 20 1969 10.19 1970 10.33 winter peak 15 1971 9.54 summer peak 1972 8.57 AMF(m3/s) 10 1973 14.16 1974 12.90 5 1975 9.12 2 5 10 25 50 100 500 1976 10.69 1977 8.85 0 EV1 y 1978 22.33 -2-1 0 1 2 3 4 5 6 7 1979 12.60 30 1980 17.66 LO2 1981 18.61 25 1982 10.33 1983 14.32 20 1984 14.99 1985 11.44 15 1986 10.77 AMF(m3/s) 1987 16.92 10 1988 7.51 1989 14.82 5 2 5 10 25 50 100 500 1990 17.66 1991 12.90 0 GLYDE & DEE CATCHMENT &DEE GLYDE 1992 11.51 -6 -4 -2 0 2 4 6 8 1993 18.81 Logistic reduced variate 1994 11.96 1.5 1995 21.46 LogNormal 1996 10.55 1.4 1997 12.00 1.3 1998 10.33 1.2 1999 10.40 2000 10.48 1.1 2001 11.29 1 2002 14.65 log10(AMF) 2003 8.95 0.9 2004 11.86 0.8 0.7 2 5 10 25 50 100 500 0.6 -3 -2 -1 0 1 2 3 4 Normal N(0,1) y COMMENTS 1.Convex upwards pattern leading to a flattening out at the upper end of the EV1 probability plot 2.Linear Score(subjective):EV1=3, LO2=1, LN2=2 3.Shape Codes(subjective):EV1=S1, LO2=S2, LN2=S2 *For Explanation of Scores and Codes see in Introductory Page 6070 RIVER MUCKNO L.