I’m modelling a water body where I have measured the inflow and outflow. Setting up a flow boundary condition at one end of my model was straight-forward, but I’m confused on how to set the outflow at the other end. A flow boundary would lower the local water level too quickly and crash EFDC, so I think I want a hydraulic structure to control the outflow. How do I set it up properly? Can it be on the boundary of my grid? What are the ‘Head’ and ‘Flow’ columns in the table supposed to contain?
You may see an example of how to set up a hydraulic structure in several of our test cases on this website, eg Yen & Lee Test Case.
In your example the hydraulic structure boundary should be set on the most downstream cells, as in the test case above. The “head” and “flow” columns dictate the relationship between hydraulic head and flow at the structure.