Question
Hello Brigitte,
I work for a small natural history museum and we have a small
pond behind the museum. The pond seems healthy (and is very
popular with visitors) but since August or so I have had to refill it
every 3 days or so because the water levels go down too quickly.
We don't appear to have a leak (there is not wet area around the
pond on dry days) There are cat tails and grassses and Iris and
arrowhead, and lilies in the pond, is it possible that the plants
are taking up all that water? The pon is about 8 feet by 6 feet
and is about 4 feet deep in the middle but much more shallow
on the sides.
-Thank you for your help,
Betsy Bennett
curator
The Nature Museum at Grafton, Vermont

Answer
Hello Betsy!
Ponds can lose quite a bit of water every day in the hot summer months (even more so if it is windy).
You did not say how much water you have to top off and if there is a water feature like a fountain and/or waterfall which can increase water loss.