The purpose of the study described in this supplement of Chapter A (Supplement 4) is to construct, simulate, and calibrate a groundwater-flow model that represents the hydro-geologic framework and related groundwater-flow conditions described by Faye (2012) and Faye et al. (2013) within the vicinity of the Hadnot Point–Holcomb Boulevard (HPHB) study area, U.S. Marine Corp Base (USMCB) Camp Lejeune (Figure S4.1). Multiple variants of the groundwater-flow model were constructed and are described herein. The models simulate groundwater-flow conditions in the Brewster Boulevard, Tarawa Terrace, and Upper and Middle Castle Hayne aquifer systems from January 1942 to June 2008. Much of the discussion and analyses described herein parallel and partially duplicate methods and approaches described in similar reports of groundwater-flow investigations at Tarawa Terrace (TT) and vicinity by Faye and Valenzuela (2007). Model results were eventually used within several contaminant fate and transport models described by Jones et al. (2013) and Jang et al. (2013) for the historical reconstruction of finished-water3 concentrations within the service areas of the Hadnot Point and Holcomb Boulevard water treatment plants (HPWTP and HBWTP, respectively). This supplement focuses on the description of groundwater-flow model geometry, boundaries, hydraulic properties, calibration, and sensitivity analyses.
