delta-temperature (dt) for GWE

[VeloVolant]

Following a recent discussion on the google MF group, I would like to be able to assign a delta-temperature (dT) between pumping and injection (geothermal) wells (PW and INJ), a bit like what does the CTS package. a dT is very common e.g. when using a heat exchanger such as a heat pump, and is crucial for estimating the feasibility of geothermal projets, because of (1) the risk of the dT recycling from INJ -> PW and (2) of the thermal plume and its impact on existing geothermal installations and sometimes on other "groundwater users".
One dt should be attached to one or several PW with various rates, feeding a single exchanger with a single dT (constant or transient), and the INJ may also be several with various rates. The feflow "open loop" module is a good example of what such function should be able to do.

[emorway-usgs]

A quick note that this is related to discussion #1314.

@VeloVolant, for the time being, the API version of MODFLOW might be a good option for you, similar to what White et al. (2023) did, but for GWE instead of GWT.

[emorway-usgs]

Linked to this discussion on the MODFLOW Development Plans Wiki.