The following questions refer to Figure, the IDF curve for Houston, Texas.(a) What is the...

The following questions refer to Figure, the IDF curve for Houston, Texas.

(a) What is the return period of a storm that recorded 3.1 in./hr for 2 hr in Houston?

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(b) What amount of rain (in.) would have to fall in a 6-hr period to be considered a 100-yr storm in Houston?

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(c) What is the return period of a storm that lasts 1 hr and records 3.5 in. of rainfall?

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(d) Develop and plot a 6-hr, 100-yr storm design rainfall using 1-hr time steps (see Fig.). Assume the maximum hourly value occurs between hours 3 and 4.

(i) Find the rainfall intensity for a 1-hr duration and plot the rainfall intensity in in./hr between the hours of 3 and 4 on a bar graph.

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(ii) Then, find the rainfall intensity for a 2-hr duration; multiply the intensity by the duration of rain to get the volume. Plot the difference between the 2-hr duration volume and the 1-hr duration volume for hour 2 to 3 on a bar graph.

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(iii) Continue in the same way for the 3-hr duration, plotting the new intensity to the right of the maximum (hour between 4-5). (Find the 3-hr volume and subtract the 2-hr volume.)

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(iv) Then, find the rainfall intensity for a 6-hr duration and the respective volume. Plot the remaining volume (6-hr minus 3-hr) over the 3 hr, assuming equal distribution between them, with two bars to the left and one to the right of the maximum (time intervals 0-1, 1-2, and 5-6).

Figure

Intensity-duration frequency curves for Houston, TX.

Fig.

(a) The unsaturated parcel of air at each elevation is colder than its surroundings. The atmosphere is stable with respect to unsaturated, rising air.

(b) The lifted, saturated air parcel is warmer at each elevation than its surroundings. The atmosphere is unstable with respect to saturated, rising air.