CE 394K.2 Surface Water Hydrology
Homework #7 Frequency Analysis
Spring 1999
1. The attached Excel file Guadalupe.xls
(also Guadalupe.csv
in comma separated text form) contains the annual maximum flow (cfs) for
the Guadalupe River at Victoria for each water year (1 Oct - 30 Sept) from
1935 to 1997. These data are also stored in the LRC server
in \class\maidment\gishydro99\frequency. For these data:
-
Calculate the mean, standard deviation and coefficient of skewness for
the original data and for their logarithms to base 10.
-
Prepare a probability plot of the discharge as a lognormal distribution
assuming the Blom plotting formula for determining the exceedance probability
-
Using this distribution, estimate the 10-year and 100-year return period
discharges (cfs) for the Guadalupe River at Victoria.
-
The October 1998 flood of the Guadalupe River at Cuero is estimated to
be 394,000 cfs. How does that compare to your estimated 100 year
flow downstream at Victoria?
2. The attached Excel file Austin.xls
(also Austin.csv
in comma separated text form) contains the annual maximum daily precipitation
(in) recorded at Austin airport from 1931 to 1997. These data are
also stored in the LRC server in \class\maidment\gishydro99\frequency.
For these data:
-
Calculate the mean and standard deviation of the original data
-
Prepare a probability plot of the annual maximum daily precipitation (in)
as an extreme value type I distribution using the Gringorton plotting formula
-
Using this distribution, estimate the 10-year and 100-year return period
values for daily precipitation (in)
This assignment is due in on Tues, April 13