open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi everybody, I’m working at the regional scale on the pertuis charentais ( France ) with a focus into the marina of La Rochelle. The resolution is 2km offshore to ~6m into the marina. For the moment i work in 3D, with tide data (fes 2014) and meteorology (U,V,pressure varying in time and space).
The problem is that, in the marina , the low tide isn’t well reproduced during spring tides (tide range > 4 m) , while 5 km offshore the signal corresponds to the reality. I have a kind of asymmetry, with an offset of the low tide (~1H30) and and offset in the height (~ 1-1m5) which is quite sizable…. Concerning high tide i do not have any problem.. According to the battery of test that i realized i think the problem mainly comes from the fact that the are is very shallow water and we have a lot of tidal flats.

The test that had a few or no influence onto the low tide asymmetry :
- Modifying law of bottom friction
- Raising or lowering number of bottom smoothings
- Raising or lowering number of vertical levels
- Modifiying turbulence model
- Raising of lowering velocity diffusivity
- Non hydrostatic mode
- Minimal value for depth
- Option for the treatment of tidal flats
- Treatment of negative depths
- Modifiying the grid resolution
- Scheme for advection of velocities = 3,4
- Threshold for viscosity correction on tidal flats => when = 2 , can improve around 20cm the low tide level
- Raising of lowering bottom friction around the area => when = 0.001 for manning , it can improve around 20cm the low tide level

In fact, it’s only when i remove tidal flats around the marina , that i can expect a good reproduction of the tide.
So, if you have any advices, or if you had the same kin of problem in a very enclosed area with a lot of tidal flats, i need your help !

ps: i joined a casfile with typical parameters that i use (concerning the scheme for advection of velocities 14 and 13 the modle is not working, maybe it comes from here but i cant solution it ...

Ok, problem solved
In fact, the problem comes from the fact that i didn't use the option CALIBRATE THE SEA LEVEL which is essential to define the mean sea level at your study site...
I was 3m under my Mean sea level, and, in my study area, because i have a lot of tidal flats discovered during spring tides, the space allocated for the decreasing tide was very small ( a channel with 20m width maximum ) so that's why i didn't have enough space to empty the semi enclosed basin...