# Modeling an infiltration trench in SEEP/W

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Posts: 3

Hi! I'm working with SEEP/W with a student licence, trying to model an infiltration trench used as BMP to reduce stormwater runoff, but I have some doubts:

1. I'm not sure about the correct BC for my problem, in particoular if I should use the "potential seepage face review" along the sides of the trench or not;
2. I don't understand how to interpret the results in terms of water rate and water flux, that I would like to compare with the values I estimated by calculations.

Thanks to everyone that could give me some advices.

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• Posts: 5
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Hi Arianna, good questions.

1. It depends on what you're modeling. If your water level is steady, you can just use a head boundary condition and don't need the seepage face review. However, if you're performing a transient analysis, you may need the potential seepage face to model changing water levels. I've attached a writeup about this case. You can find the model and more examples here:https://lms.seequentlearning.com/learner_resource_list
2. For calculating flow values, we recommend using water rate. The water rate is per meter out of plane, so you can multiply the water rate given by GeoStudio by the length of your trench to estimate the seepage.

I hope this helps.

• Posts: 3
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Thank you for the answer! I'm modeling rainfall as a costant flux above the edge of my trench, so maybe I don't need the seepage face review.

• Posts: 2
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Hi,

I am modeling some drainage trenches and wondering the same thing.

Does a trench get the drainage BC or not?

It changes the flow value by a lot if you assume the trench to be a drainage BC

• Posts: 4
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Hi,

I think you should try for modeling an infiltration trench in SEEP/W you should use the potential seepage face boundary condition along the sides if you expect seepage to occur at those boundaries….

This helps simulate realistic flow conditions. To interpret results compare the water rates and fluxes from SEEP/W with your calculated values by checking if the simulated infiltration rates align with your expected rates considering factors like soil properties and trench dimensions.

Thanks😊

• Posts: 3
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SawyerMosier did you model also a drain inside the trench? And if you did, which boundary condition did you apply to it?