In the context of flood frequency analysis, what is the primary limitation of using the Gumbel (Extreme Value Type I) distribution when dealing with very extreme flood events, particularly in regions with significant historical outliers?
Question 2
When performing regional flood frequency analysis, what is the primary criterion for grouping gauging stations into a 'homogeneous region'?
Question 3
The 'risk' or 'reliability' of a hydraulic structure designed for a specific return period flood is defined as the probability that the design flood will be exceeded at least once during the structure's design life. If a culvert is designed for a 25-year flood and has a design life of 10 years, what is the risk of failure?
Question 4
What is the primary reason for using 'historical data' (information about floods outside the systematic record) in flood frequency analysis?
Question 5
Which of the following statistical tests is commonly used to assess the 'goodness-of-fit' of a chosen probability distribution to observed flood data?
