Data Lookup
Precipitation Frequency
ISWS Bulletin 75, Table 7 (Northeast Section)
Rainfall Depth:
-- inches
Recommended Huff Quartile: 3rd
Curve Number Lookup
SCS Curve Numbers by Land Cover and Soil Group
| Soil Group A | Soil Group B | Soil Group C | Soil Group D |
|---|---|---|---|
| -- | -- | -- | -- |
Time of Concentration Calculator
Kerby-Kirpich Method
Overland Flow (Kerby Equation)
Channel Flow (Kirpich Equation)
Overland Time:
-- min
Channel Time:
-- min
Total Tc:
-- min
Quick Reference
Common 24-Hour Precipitation (NE Illinois)
| Return Period | Depth (in) |
|---|---|
| 2-year | 4.33 |
| 5-year | 5.39 |
| 10-year | 6.26 |
| 25-year | 7.36 |
| 50-year | 8.25 |
| 100-year | 9.21 |
Huff Quartile Selection
| Storm Duration | Quartile |
|---|---|
| ≤ 6 hours | 1st Quartile |
| 6 - 12 hours | 2nd Quartile |
| 12 - 24 hours | 3rd Quartile (Default) |
| > 24 hours | 4th Quartile |