Water balance error when saving each timestep

[visr]

check_water_balance_error runs on saveat, by default once per day. We support writing output for each timestep with

[solver]
saveat = 0

For e.g. the HWS model this fails the water balance check at t=0, whereas it works even with a tiny saveat = 1 second.

┌ Error: Too large water balance error
│   id = Basin #1340
│   balance_error = 84387.34177215189
│   relative_error = 2.0
└ @ Ribasim d:\repo\ribasim\Ribasim\core\src\callback.jl:317

Perhaps the check should be disabled for saveat = 0? One workaround now is to set large water balance tolerances:

[solver]
saveat = 0
water_balance_abstol = 1e30 # optional, default 1e-3
water_balance_reltol = 1e20 # optional, default 1e-2

Also I see that currently we fail the check if both the absolute and relative tolerance is exceeded. Shouldn't this be either?

[Huite]

Shouldn't this be either?

Indeed, should be either.

[visr]

This may also be related to the water balance error the iMOD Coupler team sees when running the backwater model with groundwater exchange through BMI. #1896 may already help with this.