12 December 2001
Storm Water Runoff and High Tide or Storm Surge. The orientation,
magnitude, and thickness of storm water runoff plumes are functions of the amount of
river discharge, wind speed, direction, and duration, local ocean currents due to tides
and surge, and local bathymetry. The runoff plume generally spreads out in a thin-layer
over a large area as it mixes with ambient seawater. As a river discharges along the
coast, the storm water runoff plume tends to spread in a longshore direction, parallel to
It is unclear as to whether or not dissolved and suspended plume
components spread similarly throughout the water column. Thus, sufficient turbulence
caused by river eddies or strong winds can cause particles to remain in suspension.
With time, as turbulence decreases, particles will come out of suspension and deposit
on the seafloor.
Coastal engineers should be aware that a coupling action between storm
water runoff dynamics coincident with high tide or storm surge would undoubtedly have
an effect on coastal project designs.
A lack of information covering this topic in the literature indicates that a
need exists to more closely study these phenomena by conducting in situ observation
and combining this data with analytical models to simulate the coupled effects. We
solicit any comments and information regarding this phenomenon.