UZF with SFR2 vs UZF with RIV/DRN

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aliyya tirangga

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Jan 1, 2026, 10:42:50 PM (13 days ago) Jan 1
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Happy New Year everyone,

I hope you are all doing well. I have noticed that in many documentations, examples, and tutorials, the UZF package is commonly used together with SFR2 to represent the surface water network.

Given that SFR2 requires relatively complex input and detailed stream network data, I would like to ask:

1. Is it conceptually still acceptable to replace SFR2 with simpler boundary packages such as RIV, DRN, and/or GHB when using UZF, provided that streamflow routing itself is not a key objective of the model?

2. In cases where the simulated water table rises above the land surface (or model top), UZF seems to reject part of the recharge. Is this “surface leakage/rejected recharge” physically interpreted as surface runoff/ponding, or is it purely a numerical mechanism to maintain stability?

My main concern is to maintain conceptual consistency while modeling the unsaturated–saturated flow processes, without introducing the additional complexity of full streamflow routing if it is not necessary for the study objectives.

Any clarification or best-practice recommendations would be greatly appreciated.

Thank you in advance.

Richard Winston

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Jan 2, 2026, 4:47:09 PM (12 days ago) Jan 2
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1. If streamflow routing is not required, you can use simpler boundaries.
2. Rejected recharge can be routed to SFR, but if that doesn't happen, rejected recharge is removed from the simulation. 


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