Slope-Area Method Could Not Converge Error

[jsmith22]

Hello All,

I am getting the following warning: “Slope-Area method could not converge on a starting water surface elevation within the specified number of trails. The program used critical depth as the starting water surface elevation”

This is causing my water surface to default to critical depth, which gives inaccurate results for the rest of the modeled reach.

See attached image for an image of the resulting profile plot. The profiles that default to critical are giving me much lower WSE than is expected. Flows both above a below a certain range do not have this error and result in a profile that looks more like what I was expecting.

My downstream boundary condition is set to Normal Depth S = 0.00082. This slope is based on the approximate channel slope of the downstream reach.

I have tried to research this error, but have been unable to find much about it. Does any one have any suggestions for way to troubleshoot this issue? I have tried increasing the normal depth slope slightly and it hasn’t eliminated this problem.

Thanks,
Joey

[cameron]

What do your cross-sections near the downstream boundary look like?

[jsmith22]

My cross sections throughout the reach are all very similar with a relatively large main channel and overbank floodplains that are inundated at 100-year flow event.

See below for an image of the downstream most cross section

[Author]

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