Buoyant plumes are characterized by a distinct contrast in properties
between plume and ambient water. An understanding of their physics is
crucial for interdisciplinary study of estuarine and coastal regions
because discharge flow is often a source of nutrients, biological
species, sediment, and toxic contaminants. This book investigates the
nature of physical processes associated with near field buoyant plumes,
and describes the relationship between processes. Two field sites, one
thermal plume in Massachusetts, USA, and the Merrimack River plume,
Massachusetts, USA are studied. Observed mixing in the near-field of the
thermal plume is driven by bottom friction. The industrial plume studied
here is dynamically similar to larger geophysical plumes, but differs in
important aspects that can be fully characterized by the initial aspect
ratio of the discharging plume. Estimates of three non-dimensional
parameters, which represent mixing, spreading, and the bulk Richardson
number, suggest that a quadratic relationship exists between mixing and
spreading for the river plume. Estimates also yielded time scales for
turbulence evolution that are consistent with values in literature.