There is a nomograph program located at
http://www.kcmmb.org/FAQ/faq-default.htm which is used for determining the
evaporation rate from concrete to determine when protective measures need to
be taken to prevent drying shrinkage cracks. The nomograph is a zip program
which is downloaded and installed on your computer. The inputs are
atmospheric temperature, relative humidity, concrete temperature (pond
temperature) and wind velocity. The output is in pounds per square foot per
hour. Using average high and low temperature, average humidity and wind
velocity you could compute the 24 hour evaporation loss. A loss of 1 pound
per square foot would translate to about 1 1/2 inches.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html
"Keith Nuttle" wrote in message
...
I live in central Indiana, and we have experienced daytime temperatures
between 75 and 90 degrees with dew points of 55 to 65 degrees.

My pond has about 120 square feet of surface area.

Can someone give me an estimate, in gallons, of the evaporation during a
day.