Flood recurrence and probability graphs like the one shown below rely on historic records.The predictions for severe floods on graphs like this one are supported by few data points because data for such graphs have generally not been collected longer than a century.What effect would urbanization have on the reliability of using this kind of graph to calculate the frequency and severity of major floods?
A) an underestimation of severe flood hazard
B) an overestimation of severe flood hazard
C) Urbanization would probably not affect the reliability of estimating severe flood hazard using this graphic predictive technique.

Question

Flood recurrence and probability graphs like the one shown below rely on historic records.The predictions for severe floods on graphs like this one are supported by few data points because data for such graphs have generally not been collected longer than a century.What effect would urbanization have on the reliability of using this kind of graph to calculate the frequency and severity of major floods? 
A) an underestimation of severe flood hazard 
B) an overestimation of severe flood hazard 
C) Urbanization would probably not affect the reliability of estimating severe flood hazard using this graphic predictive technique.

Quizplus · Accepted Answer

Urbanization generally leads to increased runoff due to construction of impervious surfaces such as roads, buildings, and parking lots. This increased runoff can lead to more frequent and severe flooding events. Therefore, using historical data from before urbanization may underestimate the frequency and severity of floods in urban areas.

Flood Recurrence and Probability Graphs Like the One Shown Below