CE 374K Hydrology Homework Assignment on
Flood Frequency
Analysis
The attached spreadsheet guadalupe.xls and comma separated file guadalupe.csv
contain the annual maximum discharges of the
The data for 1935 to 1998 are plotted below. In October 1998, an enormous flood occurred
on the
(1) Plot a graph of all the data, including the flows in 1999 and 2002.
(2) Estimate the return period of annual maximum discharges which exceed 30,000, 40,000, 50,000, and 60,000 cfs directly from the data by looking at the recurrence interval between flows exceeding those magnitudes in the data from 19352002.
(3) Take the logs to base 10 of the data and calculate their mean, standard deviation and coefficient of skewness for the data from 1935 – 1998, and also including the last four years of data, i.e. 19352002.
(4) Estimate the 100
year flood on the
This assignment is due on Tuesday April 27
Annual
Maximum Discharges of 




Date of
Occurrence 
Year 
Peak
Discharge (cfs) 

1935 
38500 

1936 
179000 

1937 
17200 

1938 
25400 

1939 
4940 

1940 
55900 

1941 
58000 

1942 
56000 

1943 
7710 

1944 
12300 

1945 
22000 

1946 
17900 

1947 
46000 

1948 
6970 

1949 
20600 

1950 
13300 

1951 
12300 

1952 
28400 

1953 
11600 

1954 
8560 

1955 
4950 

1956 
1730 

1957 
35300 

1958 
58300 

1959 
10100 

1960 
23700 

1961 
55800 

1962 
10800 

1963 
4100 

1964 
5720 

1965 
15000 

1966 
9790 

1967 
70000 

1968 
44300 

1969 
15200 

1970 
9190 

1971 
9740 

1972 
58500 

1973 
33100 

1974 
25200 

1975 
30200 

1976 
14100 

1977 
54500 

1978 
12700 

1979 
19300 

1980 
11600 

1981 
105000 

1982 
18500 

1983 
10900 

1984 
3280 

1985 
10600 

1986 
13700 

1987 
83400 

1988 
3900 

1989 
4280 

1990 
5230 

1991 
17000 

1992 
61500 

1993 
17700 

1994 
13300 

1995 
39600 

1996 
9760 

1997 
32700 

1998 
20600 

1999 
466000 

2000 
6220 

2001 
39300 

2002 
71700 