Use of multi-resolution, three-dimensional hydrodynamic and water-quality models to assess response to nutrient load reductions in Barnegat Bay-Little Egg Harbor estuary, New Jersey, USA

A coupled three-dimensional hydrodynamic water-quality model has been applied to Barnegat Bay-Little Egg Harbor Estuary, a shallow, back-barrier lagoon located along the central New Jersey coastline. The study aims to enhance understanding of phytoplankton dynamics and nutrient cycling and to quantify estuarine response to potential nutrient load management strategies. The model was calibrated with data from Spring and Summer of 2012 and adequately reproduced spatiotemporal water-quality variability, distribution patterns, trends, and gradients throughout the system. The calibrated model was used to run scenarios for evaluating estuarine response to various nitrogen load reduction intensities. Model results show that geographically focused, variable nitrogen reductions can mitigate the effects of eutrophication and promote improvements in water quality. This study illustrates the role of modeling in developing informed management strategies, highlights complex, nonlinear responses of estuarine environments to anthropogenic influences, and demonstrates how models can be used to develop adaptive, location-specific nutrient management practices.