Evaporation Concern

I have a question about pond/stream evaporation for any seasoned pond owners
out there.

My pond is about 23'x23'x24 inches deep with a 63 foot stream. The width of
the water in the stream is about 14 inches. The stream bed is small river
pebbles.

Temps have been in the 70-80's in the day and 50's at night with a low-med
humidity. No rain during this period

I don't understand what the water level in the pond goes down about 1/4-1/2
inch in about 2 days. I had thought I had a leak, but now not sure, since
there is no water near the ground level anywhere. Though the local water
table is very very low, due to no rain for the past 45 days.

Can I assume that since the water is traveling over the river pebbles which
may increase surface area, can I be losing some much water and have to
replace it often?

Anyone out there with the same pond/stream specs also experience a loss of
water?

Steve