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----- Original Message -----
From: Rogelio M. Espinosa
To: hydrologymodel@...
Sent: Monday, June 11, 2007 7:37 AM
Subject: [hydrologymodel] daily rainfall data from non-recording gage

dear members;

I am trying to develop an IDF for our locality using probability analysis.
However, i have this problem on rainfall data. the only data available is
daily rainfall depths and duration for about 25 years taken from a non
recording gage. In developing the IDF, one has to obtain the average
rainfall intensities for time increment windows of 15 min , 20 min , 30
min, 45 min, 60 min and up to 72 hrs (either on annual series or partial
series basis ) and treat these with probability analysis using appropriate
models. My problem is how to get the average rainfall intensities for time
increment windows enumerated above with data on non-recording gage. What i
know is that it would be very much easier if you have outputs from a
pluviometer. In the absence of data from recording gages , Is it safe to
say that these average intensities can be computed by merely dividing
rainfall duration ( say t= 5.0 min ) from rainfall depth (say d = 10 mm )
and consider the quotient ( i = 120 mm / hr ) as part of time increment
window of 5 min? if so, what about for rainfall duration not within the
time increment windows?

any suggestion / s will be greatly appreciated . .

Thnk you and more power.

rogelio m. espinosa
College of engineering & technology
western mindanao state university
zamboanga city, philippines
telefax no: 062-991-9365