1A) (3 points) The total precipitation for the month of August (P_{AUG}) in Groton for a 10 year period was as follows. What is the highest volume (inches) of precipitation in August to be expected in a 20 year period? (Use the arithmetic/probability graph paper or modify the Excel spreadsheet, both available at http://environmentalet.org/env245.) ANSWER: 4.01 inches.
Rank |
p |
z-value |
P_{AUG} (in) |
1 |
0.05 |
-1.64485 |
3.92 |
2 |
0.15 |
-1.03643 |
3.49 |
3 |
0.25 |
-0.67449 |
3.27 |
4 |
0.35 |
-0.38532 |
3.07 |
5 |
0.45 |
-0.12566 |
2.71 |
6 |
0.55 |
0.125661 |
2.52 |
7 |
0.65 |
0.38532 |
2.43 |
8 |
0.75 |
0.67449 |
1.85 |
9 |
0.85 |
1.036433 |
1.46 |
10 |
0.95 |
1.644854 |
1.38 |
2) A storm contributes 2.5 inches of runoff to a 5 acre parking lot.
Depth = volume/area:
The flow rate would probably decrease as the depth of water in the basin decreased.
3) (2 points) What is the maximum intensity of rainfall (in inches per hour) lasting 50 minutes, expected in Harford, CT, once during a ten year period? (Use an IDF curve for Hartford).
2.0 inches per hour. See IDF curve.