“…Groundwater quality remains a critically important problem impacting the worlds water resources. Several papers explore better ways to understand the progress of remediation efforts through improved confidence (Brouwers et al ), data assimilation (Ross and Andersen ), and the use of non‐Fickian transport techniques (Burnell et al ). Groundwater transit time links all these concepts together and Abrams and Haitjema () explore the role that aquifer geometry plays in water age and flow paths.…”