GROUNDWATER FLOW AND CONTAMINANT MIGRATION IN THE BRUNSWICK GROUP (NEWARK BASIN)
A 28-day aquifer test conducted in Roseland Borough, Essex County, New Jersey presents insights to groundwater flow characteristics in the Brunswick Group of the Newark Basin. The test was conducted in the Towaco Formation, which exhibits typical bedrock structure of the sedimentary deposits of the Brunswick Group. The results of this aquifer test could not be interpreted by standard analytical methods because of fracture control on groundwater movement. Pumping response models based on ideal, leaky, vertically or horizontally anisotropic aquifers are insufficient to explain observed drawdown patterns. An empirical approach to interpreting the test data supports the concept that groundwater flow is controlled by bedding zones. Vertical fractures are regionally less significant, but are locally important because they provide leaky conduits between the bedding planes. Groundwater flow through bedding zones explains the strong connection between wells along strike withdrawing water from the same bedding zone, and why these aquifers, which are often unconfined at the surface, always behave as confined aquifers at depth. This conceptual groundwater flow model, and its impact on contaminant migration, can be applied to similar sedimentary deposits.