Often times we will end up having two different bathymetry data sources and we would like to know how different those data sources are. Eventually, we will use those data to create bathymetry in EFDC model.
EFDC model allows an easy comparison between bathymetry at two different models.
For example, we will use an EFDC model of Ohio River which can be downloaded from EFDC Explorer website
Step 1: Load the model bottom elevation from “Viewing options”
Step 2: In the next step what we are going to do is change the bottom elevation of this model and then reduce the bottom elevation by 1 m at all cells.
Go to “Grid & General” and Under bottom Elev. Adjustments enter the value of additive factor to -1.
Step 3: Save the model with a new name “OhioRiver_newbathymetry”.
Step 4: Now, we have two models: a) Previous Ohio River model and b) OhioRiver_newbathymetry
Step 5: When you are in “OhioRiver_newbathymetry”, go to Comparison Data under Post Processing Options, then click “Load Comparison Model”. The following will pop up:
Then go a head and click yes. It would say “Bad or missing Surface Water Levels (i.e. EE_WS)! then click ok. Then the following window will pop up:
Click on the browse button and find your previous model. IN my case it was “EFDC_MOdel_04” that was downloaded from “EFDC Explorer” website. After loading the model, click on Enable Model Comparisons.
Step 6: Go to View Plan and press “Alt-M”. Then we will see that the bottom differences would be -1 as follows.
Similarly, you can use different data sources to create separate models and do the comparison on bathymetry.
Let me know if you have any better solution for comparing bathymetry through comments.