Question? About Depths


I have a 1D river model with 105 cells of varying lengths and widths. There are 17 inflows to the grid at different locations and an open outflow boundary governed by time series. I am comparing this model to a different 1D model called PCSWMM. PCSWMM uses irregular transect data to define cross-sections of a river similar to HEC-RAS. These transects also have access to flood plain. The cell widths in my 1D EFDC model are active channel widths ranging from 9m to 57m.

When I compare the results of the two models, I get a very good agreement for flows and velocities. R-square values for both these quantities are above 0.9. However, when I compare the depths of the two models, I see that EFDC computed depths are lower by approximately 1m. The timing of the peaks is good but there is a general offset of 1m between the data.

I am wondering if this is a calibration problem or is it because of the difference in the grid structure of the two models? Although velocities are in good agreement, will this difference in depths have impact on sediment and toxic modeling?

Thank you for your guidance!


Hi Sannan,

You are comparing two different types of model. EFDC is a hydrodynamic model and PCSWMM is a hydraulic model, so I am not sure we are comparing apples to apples here. So, the initial conditions you used on PCSWMM and EFDC might be different resulting in slightly different depths. Not sure how to advise you, but we are comparing two different models with different parameters controlling the results.