TUFLOW Message 3991: Difference between revisions
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|type=[[WARNING]]
|message_desc=Numerical solution has resulted in a negative depth at specified location. This indicates that the model is unstable or unhealthy in this area.
|suggestions=Import the messages layer in to your GIS package. Check for the number and time at which these warnings occur. A few warnings at a single location or timestep in the simulation are not normally an issue. Persistent warnings however warrant further investigation. Check the following: <br>
* Depth discharge curve for Q pits;<br>
* Incorrect bed levels upstream or downstream;<br>
* A large change in cross-sectional area;<br>
* Very steep channel entering a gently or adverse grade channel;<br>
* Sudden change in flow area (for example a culvert width entered in mm not m, 1200mm rather than 1.2m);<br>
* Issues with 1D/2D linking (incorrect use of Z flag on culvert inlet / outlet);
* Too high a timestep; and<br>
* Too small a nodal area.<br>
|discussion_page=* [[Talk:TUFLOW Message 3991|Discuss Message 3991]]
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