At Groundwater Week 2020, Reed Maxwell presents this year’s NGWA Darcy Lecture, which focuses on groundwater and the water cycle. Maxwell directs the Integrated GroundWater Modeling Center (IGWMC) at Princeton, where he is also a professor in Civil and Environmental Engineering (CEE) and the High Meadows Environmental Institute. On episode 18 of Drilling In-Site, we talk groundwater modeling and how it affects drillers.