On Sat March 4 I photographed the ice level under the bridge:
The question is how deep would the water have been if I had been able to measure the depth when the Creek had been so covered with ice?
So on Sun April 2 I measured the various levels of concrete under the bridge, that water level, and the depth of water at my "standard" position = 36cm.
The ice appeared at this marke
The difference between the "45"cm ice mark and the "86"cm mark is 41cm, and the depth under the bridge is 36cm so the depth of the Creek to form the layer of ice on Sat Mar 4 must have been 77cm.
I can now determine the depth from the water level on the side of the bridge - at least until the stream dry up.
W O B