If the recurrence interval of a stream is 8.3 years, then the probability of flooding on this stream is: To determine the probability of flooding on a stream with a given recurrence interval, we use the formula: = 1 P= N 1 Where: P is the probability of flooding in any given year N is the recurrence interval (in years) Given that the recurrence interval of the stream is 8.3 years, we can calculate the probability of flooding as: = 1 8.3 P= 8.3 1 0.1205 P0.1205 So, the probability of flooding on this stream is approximately 0.1205, or 12.05%