Reed Maxwell

Reed Maxwell
Director, Integrated GroundWater Modeling Center
Princeton University
Department of Civil and Environmental Engineering, High Meadows Environmental Institute
Fields of interest
Hydrologic impacts and feedbacks under climate change
Description of scientific projects
My research is interdisciplinary in nature and is focused on the development and application of numerical models to investigate a range of water-related questions. My interests span a variety of hydrology, water resources and water quality topics including: surface water and the terrestrial hydrologic cycle; interactions of the land-surface, surface water and groundwater, and the atmosphere. The application of numerical models to water resources problems, with their inherent complications, is difficult. Because of this, I develop models that draw on novel numerical methods and parallel or high-performance computing. My work is collaborative and I pursue lines of inquiry that transcend scientific and disciplinary boundaries by using models to understand and bridge scales and processes. The hydrologic cycle is composed of a number of coupled processes, yet it is seldom treated as such. Often models are developed in a compartmentalized manner that follows scientific and disciplinary boundaries and ignores important process interplay. In an effort to provide a more integrated approach, I have led the development of a suite of unique, fully coupled models of the hydrologic cycle. These models simulate the cycling and movement of water and contaminants at watershed and larger scales. This has involved coupling land surface models, which have traditionally been highly parameterized, with more so-called process-based vadose and groundwater models. Relaxing some of the more limiting assumptions involved in the parameterizations in land surface models necessitated the development of a whole new class of coupled models. Additionally, I have led the development of fully-coupled groundwater-to-atmosphere models. These efforts have resulted in a number of models (ParFlow, PF.CLM, PF.ARPS, PF.WRF) that more accurately represent fluxes of water in the terrestrial environment. Model results have shown significant interplay between groundwater and land-surface energy processes that persist into the lower atmosphere. These simulation platforms can be combined with my Lagrangian transport code to simulate watershed transport and residence times which may be used to understand watershed scaling. I have also used these models to diagnose watershed response and feedbacks to a changing climate and have shown that the hydrologic cycle responds as one complete, coupled system and components often oversimplified in previous analysis, such as groundwater, play an important role.