William,

Perhaps the reason you are getting zero flow is that it appears that your tidal elevation fluctuates from -0.01 to 0.01. This very small difference may give zero flow. A recent model I completed has tides which fluctuate from 0.0' to 3.2' for a 2-yr storm event, and 5' to 8' for the 100-yr storm event. Check the tide tables in your area to get a feel for the proper range of fluctuation.

Andrew B. Scott, P.E.
ascott@RKKENGINEERS.COM