hydrogeologist

I apologise if this subject has been posted previously but I have searched an not found it!

I am trying to represent a shallow but extensive excavation (of aquifer material) to model the impact of its development on heads in the adjacent aquifer and surface water bodies (seasonal lakes) existing in the unconfined aquifer.

Groundwater levels in the aquifer decline to low levels in the dry season when the lakes also become dry and the mining takes place. During the wet season, groundwater levels rise and the lakes re-fill by lateral flow and direct recharge. The mine voids also become flooded in this same way (preventing mining - no dewatering is carried out).

However, evaporation is increased by creation of the mine voids, which also are likely to delay the overall groundwater level rise in the aquifer and delay the flooding of the seasonal lakes.

To model this, I intend to define the (non-flowing) lakes as very high conductivity and storage. Initially I wish to define the remaining areas with uniform aquifer properties and model steady state conditions before varying the nodal aquifer properties (to very high conductivity and storage, like the seasonal lakes) to simulate the growth/development of the mine void (over several years) and model its impact on groundwater levels and the levels in the lakes.

Can I assign time-variant nodal aquifer properties (conductivity, storage) in parts of the model?

Regards

Thomas