Q1: In a catchment area covering 100 km 2 , the average annual precipitation observed at five rain gauge stations is as under:
Station
Precipitation (mm)
1
600
2
1200
3
800
4
600 400
5
Find the number of additional rain gauge stations and also the rain gauge density if permissible error is
10%.
Q2: The give table is a record precipitation from a recording gauge for a storm in a big city for a period between midnight and 11:15 A.M. on the same day. For the data given calculate rainfall intensity (in/hr) as shown in the table. Also develop the rainfall hyetograph and mass curves. Find the maximum intensity rainfall for the gauge in in/hr.

Q: 1.19 (Hydrology and Floodplain Analysis by Bendient) A small urban watershed has four rainfall gauges as shown in the figure below. Total rainfall recorded at each gauge during a storm event is list in the table. Compute the mean areal rainfall for this storm using (a) arithmetic mean (b) Thiessen method.

Q4: The design storms used as input in any hydrologic model for drainage design or flood modeling can be derived from Intensity-Duration-Frequency (IDF) curves as shown below for Houston Texas.
In the above curve; a) 100 yr, 2 hr storm corresponds to ___________ in/hr rain intensity. b) 10 yr, 24 hr storm equals _____________ in/hr or _______________ inch in 24 hrs. c) What is the return period of a storm that recorded 3.1 in/hr for 2 hours in Houston? d) What amount of rain (in) would have to fall in a 6 hr period to be considered a 100-yr storm in
Houston? e) What is the return period of a storm that lasts one hour and records 3.5 in of rainfall? f) Develop and plot a 6-hr, 100-yr storm design rainfall using 1-hr time step. Assume the maximum hourly value occurs between hours 3 and 4.
Q5: What is the probability that at least one 50-year flood will occur during the 30-yr lifetime of a flood control project?
Q6: What is the probability that the 100-yr flood will not occur in 10 yr?
Q7: What is the probability that the 100-yr flood will occur in 100 years?