This archive contains the code and other files to demonstrate the creation and application of an impulse-response emulator for process-based groundwater flow and transport models in MODFLOW/MT3D. This includes creating a synthetic modeling environment in MODFLOW/MT3D, using PEST++ to derive an impulse-response (A) matrix (as described in White et al., 2020), using this A matrix to create a groundwater transport emulator model, and providing a workflow to evaluate the performance of this emulator across a range of flow and transport model parameters.