Development of an Integrated Profiling System for Field Studies of Plumes in the Marine Environment
Authors: McDowell S.E. , Albro C.S. 
Published: October 2008

INTRODUCTION

The transport and fate of manmade pollutants released in the marine environment are greatly affected by the myriad advective and mixing processes that characterize a specific receiving-water region. Predictions of the horizontal transport of pollutants can be made from a combination of point-wise (Eulerian) current measurements, drifter (Lagrangian) trajectories, and hydrodynamic modeling of various combinations of wind, tidal, and low-frequency driving forces. Nevertheless, these analyses represent only predictions of the movement of particles; the small-scale mixing processes, which greatly affect pollutant transport and dispersion, cannot be adequately resolved by the current measurements or models alone. This is especially true in estuaries and coastal regions where irregular topography, intense water column stratification, and aperiodic forcing from the wind contribute to a complex and dynamic environment. Accurate, quantitative analyses of pollutant transport and mixing in these dynamic regions can be made only from high-resolution field measurements of the three-dimensional and time-varying behavior of the pollutant in the receiving-water environment.

As Federal and State regulations on pollutant discharge in the marine environment continually tighten, there is growing need for improved quality and cost effectiveness of pollution-monitoring surveys in the coastal ocean. The design of these surveys differs greatly on account of the varying pollutants being released, the physical characteristics of the receiving environments, and the monitoring requirements imposed by the regulations. As discussed below, the sampling requirements for these surveys may vary, but they share a common need for measurement systems that provideAccurate, in situ measurements from a variety of sensorsHigh-resolution measurements achieved from rapid, continuous sampling while under way or profiling on-stationIntegrated navigation for continuous recording and display of vessel position, integrated with sensor dataReal-time display of measurement data so that the survey chief can monitor data quality as well as alter the survey plan if necessary to adjust to dynamic conditionsCollection of large-volume water samples from all depths in the water column for use in postsurvey analysis of chemical and biological constituentsComputerized data archiving and sample tracking system for management of digital data and custody of water samplesEase of handling and operation on vessels of all sizes Using these functional requirements as design criteria, Battelle Ocean Sciences engineers and marine scientists developed a shipboard measurement system, the Battelle Ocean Sampling System (BOSS), for high-resolution surveying of plumes from nearshore industrial discharges, municipal sewage outfalls, produced-water discharges from offshore production platforms, and a variety of ocean dumping activities. With the BOSS, the evolving, three-dimensional structure of these plumes can be mapped in real-time, using data from the subsurface sensors in conjunction with high-resolution vessel navigation data. Profile data and continuous water samples can be collected during vertical profiling or horizontal towing from vessels of all sizes. This innovative profiling system can greatly improve the quality, resolution, time efficiency, and cost effectiveness of water quality surveys as demonstrated on government and industrial projects.