See Answers to you question below (in parentheses)

Timed closure closes or opens when the corresponding head is reached. To
avoid slamming it shut, you specify the maximum rate of closure ORATE.

In head dependent, the gate position varies linearly between the heads
specified. If it is at the closed head, gate is close. If it is at the
open head, gate is open. If elevation is 1/2 way between, the gate is
1/2 open. So you see, the "position" of the gate depends on the head.
Again, an orate is specified to avoid rapid fluctuations.

Again, I don't have a whole lot of time. IF you could send the latest
file and your interface for Version 4.4H, I'll try to look at it again
(I think I deleted your previous email). If you could send me a file
that is somewhat simplified and maybe uses a ramp hydrograph on the K1,
K2, K3 lines that would be better.....

Charles I. Moore, P.E.
MOORECI@CDM.COM