Aquitard Consolidation: Spatial Diffusion Solver

This is the 2D companion to the 3D Land Subsidence simulator. Where the 3D version treats the entire clay aquitard as a single lumped block that reacts to head decline instantaneously, this simulator solves Terzaghi's real 1D consolidation diffusion equation across the clay's depth, resolved at 41 independent nodes, each carrying its own bilinear elastic/inelastic storage history. Because the diffusivity collapses once virgin (inelastic) compaction begins, the aquitard's interior can lag years behind the sand aquifers on either side — exactly the delayed and residual compaction hydrogeologists document in real over-pumped basins, and something a single-number lumped model cannot show. Watch the live depth profile diffuse inward from both drainage boundaries, compare instantaneous head decline against lagging land subsidence in the history chart below, and check how much subsidence is already "committed" even if you freeze the pump right now.