## CALCULATING PMF FOR DAM ANALYSIS

## CALCULATING PMF FOR DAM ANALYSIS

(OP)

I NEED TO CALCULATE A 25% PMF (PROBABLE MAXIMUM FLOOD) FOR AN EXISTING EARTHEN DAM. I AM USING A 1991 VERSION OF VHEC-1. I AM ABLE TO CALCULATE THE PMF BUT CAN'T FIGURE OUT HOW TO ACQUIRE THE DATA FOR THE 25%. ANY HELP IS GREATLY APPRECIATED.

## RE: CALCULATING PMF FOR DAM ANALYSIS

The NFF program is available free from USGS.

Russ Faust

Salem, OR, USA

## RE: CALCULATING PMF FOR DAM ANALYSIS

## RE: CALCULATING PMF FOR DAM ANALYSIS

Russ Faust

Salem, OR, USA

## RE: CALCULATING PMF FOR DAM ANALYSIS

## RE: CALCULATING PMF FOR DAM ANALYSIS

By taking 25% of the total rainfall and then subtracting the losses, you will end up with less effective rainfall.

In my experience, the PMF is calculated and then design may be based on a fraction of this number. This is generally a requirement of the jurisdictional agency responsible for dam safety.

## RE: CALCULATING PMF FOR DAM ANALYSIS

## RE: CALCULATING PMF FOR DAM ANALYSIS