Development of a Physically-based Sediment Transport Model for Green
Bay, Lake Michigan
Abstract
Green Bay is a large freshwater estuarine system that drains one-third
of the Lake Michigan basin. The International Joint Commission
designated southern Green Bay as an area of concern (AOC) in the 1980s
due to ecosystem degradation including eutrophication, harmful algal
blooms (HABs), hypoxia, lost or altered habitat, and reduced water
quality. Restoration studies have found excessive nutrient loading and
release of toxic materials, primarily produced in farmlands and
industrial units, to be major drivers of Green Bay
environmental/ecological issues. The Green Bay geomorphology and
restricted mixing is a barrier to the efficient transport of sediments
(as well as the accompanying nutrients and contaminants), acting as a
retention basin for Lake Michigan. The purposes of this research were
to: a) use the existing database of hydrodynamic, wave, and sediment
field data to develop a three-dimensional (3D) predictive model of
sediment transport in Lake Michigan, with an emphasis in Green Bay; b)
use the sediment transport model to contribute to understanding
ecological and environmental problems in the bay, and to recommend
long-term solutions to those problems; and c) analyze summer patterns of
circulation, wave action, current and wave-induced bottom shear stress,
thermal structure, and sediment transport in Lake Michigan, with special
attention to Green Bay.