How do I determine the 25-year 24-hour storm depth?

Find your project location on the Mean Seasonal Isohyet Map that can be found at the Hydrology Standards link (below) and determine the mean seasonal rainfall for your site. Then, use the 25-year Precipitation Duration-Frequency-Depth Curve found at the same link. Find 24-hours (1-day) on the x-axis, go up parallel to the y-axis on the graph to the mean seasonal rainfall for your site. Go horizontal parallel to the x-axis to the y-axis to read off the rainfall depth for the 25-year 24-hour storm.

Hydrology Standards

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1. How do I obtain GIS information?
2. How are Area of Benefit (AOB) fees determined?
3. How do I become a vendor?
4. How do I calculate the Flood Control flow data point? Do I need to know the post development design flows for my project?
5. How do I contact an inspector?
6. How do I determine the 25-year 24-hour storm depth?
7. How do I find out how much my Area of Benefit (AOB) fees will be for my project?
8. How do I get a vesting tentative map for my development project?
9. How do I get an encroachment permit?
10. How do I get permission for my contractor and I to temporarily use land owned by the County or Flood Control District?
11. How do I obtain a title report on my property?
12. How do I report hazardous material spills or dumping?
13. How do I report debris in creeks?
14. How do I report debris on private property or a vacant lot?
15. How do I report the lack of garbage services?
16. How do I report unresolved garbage/recycling collection company complaints?
17. How do I record a final map?
18. How do I transfer title to my child or another person?
19. How will I know which number is the streetlight pole number?
20. How do I report a train that appears to be stuck and blocking a railroad crossing for an extended period of time?