Do you have any stream records or other agencies collecting rainfall data.  Rainfall intensity is based on amount per time.  If alll you have is daily totals you have amounts per day and from that you can find a mean daily intensity by dividing the amount by 24 hours as the daily mean intensity.  The actual instantaneous intensity may be expressed as amount per hour typically.  The value of various types of recording raingages by weighing or tipping bucket is you can express instantaneous intensities in finer time periods, such as 5 minute intervals with some systems, oreven finer if desired.  But to some degree, there should be some relationship between rainfall intensity and streamflow that might be teased out, such as working the unit hydrograph approach backward from gauged streamflow discharge rate to rainfall intensity.  If you have recording well level data, that too might be useful if you start measuring rainfall amount at frequent intervals and calibrate to streamflow rates and well water level change.  After you have some calibration period you may be surprised that you can estimate it.

From daily rainfall one cannot find the rainfall intensities. For this one should have rainfall data from self recording rainfall instrument.

Rainfall intensity is not always uniform. For instance it might begin to rain at 7.00 am when it is of high intensity and after five minutes it can subside and eventually it intensifies. it might not be easy to determine the intensity of rainfall directly from the rainfall amount. 

by the Green-Ampt infiltration modelling, one can convert the cumulative rainfall into intensity of rainfall for the particular duration. 

Please read the linked materials.

http://www.brighthubengineering.com/hydraulics-civil-engineering/58958-calculating-design-rainfall-intensity-for-use-in-the-rational-method/

Or 

Check the following thread

https://www.researchgate.net/post/How_to_calculate_rainfall_intensity

dear Ronald,

From daily rainfall, one cannot find the rainfall intensities. but may be you can determine intensity(approximately), if you know the common storms time in the close area have the same hydrologic properties.