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From: Kyle A W. <kyl...@ut...> - 2019-05-14 01:56:28
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Hi all, I've been getting very unrealistically high depth/stage values in the upstream end of my model domain, and I'm not sure how to figure out what is causing it. Currently, my model is a river delta with one upstream channel (constant discharge inlet + reflective BC inside an upstream lake) and a downstream bay with a constant tidal water level set by a nearby tide gauge (Dirichlet BC). Even for flows significantly lower than bankfull discharge, the water is spilling out of the channel and flooding the surrounding landscape in places that definitely do not normally flood. This happens even if I make the bed completely frictionless, increase the grid resolution, or start with different initial conditions. Is this something anybody else has experienced, and do you have any ideas for how I might fix it? The only ideas I have left are that it is perhaps related to (1) the datum (I am using NAVD88 in the vertical, which I believe differs from the one assumed by the model, but I wouldn't expect that to matter much over a few km), (2) slope limiting (which I don't understand well, but it is a very flat landscape), or (3) the flow algorithm (too diffusive?). I've attached pictures of the depth and a quiver plot of the flow velocities for context. Happy to send the code if helpful. Thanks & best regards, -- Kyle *----------------------------------------------------------------------------------------* *Kyle Wright* The University of Texas at Austin Department of Environmental & Water Resources Engineering |