John Doherty, Ph.D., is the 2019 Groundwater Foundation Darcy Lecturer. He is also the author of the PEST suite of software. Doherty has worked in the water industry as both a geophysicist and a modeler in a career spanning more than 40 years. He has been employed by government, academic, and consulting institutions, and presently runs his own company, Watermark Numerical Computing of which he is the sole employee.