I certainly prefer Rick's approach of taking 2/3 power of both sides.
Not sure why he has two variables, where I have one. Perhaps Rick
has given this more thought than I have.

I thought you might like to use this formula in the future for other
weirs... the odds that the length of every weir you will deal with in
the
future will be 936 is pretty slim<g, so I used a variable for that
term.
The remainder of your simplifications is fine... I didn't simplify the
constants because you didn't in your original posting.

Y'mean the OP, not "you" (in response to my posting).

Yes, the OP... sorry, I lost track of who I was responding to.

Yup, you gave this more thought than I did. I did not pay attention to
the initial posting by the OP. I simply jumped in the middle, where the
OP had replaced "L" with 936.

Actually, the OP did not replace L with 936... he hard-coded the 936 in, but
in a later posting explained that this was a length. I then generalized this
to a variable L so that he could calculate other weirs in the future using
the same formula.

Rick