Why are my storm estimates so low in Pondmaker?

Hello,

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Hello Tim,

This is likely related to some user notifications that you are getting when you compute the predevelopment cases. If you compute the 1-yr predevelopment scenario, you see that you have user notifications related to calculated and interpolated peak flows being greater than the default value of 1.5%. When this occurs, the reported flows may be different from what they should be. For instance, a peak may be occurring between time steps. The end results of this is that the results will be a little off from what you might expect.

Here is a support solution on this issue:

http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/7598.catchment-user-notification-about-the-difference-between-the-calculated-peak-flow-vs-interpolated-peak-flow-being-greater-than-1-5

This can often be resolved by using a smaller output increment. For instance, I set the output increment in the calculation options to 0.05 hours. When I run PondMaker again, the results are better.

I would recommend trying to find the right balance of results and computation run time to try to minimize this. You can see improved results using the output increment of 0.05 hours. Lower values still might yield even better results.

Please let me know if you have any questions on this.

Regards,
Scott

Hello Tim,

This is likely related to some user notifications that you are getting when you compute the predevelopment cases. If you compute the 1-yr predevelopment scenario, you see that you have user notifications related to calculated and interpolated peak flows being greater than the default value of 1.5%. When this occurs, the reported flows may be different from what they should be. For instance, a peak may be occurring between time steps. The end results of this is that the results will be a little off from what you might expect.

Here is a support solution on this issue:

http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/7598.catchment-user-notification-about-the-difference-between-the-calculated-peak-flow-vs-interpolated-peak-flow-being-greater-than-1-5

This can often be resolved by using a smaller output increment. For instance, I set the output increment in the calculation options to 0.05 hours. When I run PondMaker again, the results are better.

I would recommend trying to find the right balance of results and computation run time to try to minimize this. You can see improved results using the output increment of 0.05 hours. Lower values still might yield even better results.

Please let me know if you have any questions on this.

Regards,
Scott