Soil Resistance Update

[mitchute]

In the Beier model, the soil resistance Rs includes the time parameter. This could be the time since the beginning of the simulation or the time since the previous flow rate change. Or perhaps something else.
A couple of suggestions:

• Investigate performance with both applied.
• Investigate using the line-source expression given for the first, say, 24 hours, then inferring this value from the previous temperature response.
• Iterate to solve for the value, but it's unclear now how this would work.

However, first, we need to know how sensitive the flow correction factor is to this parameter.