## Rainfall Intensity Equation Coefficient outside of Denver

## Rainfall Intensity Equation Coefficient outside of Denver

(OP)

I'm trying to develop an IDF curve for Craig, Colorado. I'm using the UDFCD Rational Method spreadsheet and have the appropriate 1-hour rainfall depths but I can't seem find the appropriate coefficients for the Rainfall Intensity Equation (a, b, and c). Is there an adjustment factor or a table somewhere based on zone?

## RE: Rainfall Intensity Equation Coefficient outside of Denver

https://hdsc.nws.noaa.gov/hdsc/pfds/

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com

## RE: Rainfall Intensity Equation Coefficient outside of Denver

## RE: Rainfall Intensity Equation Coefficient outside of Denver

create a x,y (scatter) chart

add a trend line

display the equation on the chart

ok, 3 mouse clicks

## RE: Rainfall Intensity Equation Coefficient outside of Denver

1, 0.103903, 0.313687

2, 0.128763, 0.305261

5, 0.177688, 0.291029

10, 0.226557, 0.279501

25, 0.307198, 0.264093

50, 0.379736, 0.253163

100, 0.462293, 0.242978

200, 0.555014, 0.233734

500, 0.694905, 0.222314

1000, 0.807472, 0.215545

DDF Coefficients calculated using PDF from NOAA for Craig, CO (ID 05-1928)

Inch = a0 x (minutes ^ a1)

Where a0 and a1 are the coefficients for year yr

Please verify before use.

See http://www.hydrocalc.com/beta/rain_ddf/main.html#

You can also convert the DDF to either IDF or to Hyetograph.

Thanks