For a catchment area, Intensity – duration – frequency (IDF) curve and depth – area – duration (DAD) curve are drawn.
Which of the following statement is true for these curves when duration of the storm is increased?
1
Both DAD and IDF curve shifts inward
2
DAD curve shifts inward but IDF curve shift outward
3
Both DAD and IDF curve shift outward
4
IDF curve shift inward but DAD curve shifts outward