Shape and Initial Dilution of Sand Island, Hawaii Sewage Plume

Environmental Properties of Coastal Waters in Mamala Bay, Oahu, Hawaii, at the Future Site of a Seawater Air Conditioning Outfall

“…Studies of a buoyant sewage treatment plume dilution in Mamala Bay showed that the plume generally remained trapped below 40 m, but had a complex structure, including variable shapes and patchiness that was probably driven by variations in physical conditions such as current speed, shear, water column stratification, and internal tides (Petrenko et al, 1998). Similar complexity can be expected in this sinking plume.…”

“…Given the amount of nutrients being upwelled to the photic zone, the variety of physical factors that may influence the SWAC plume's shape in Mamala Bay, and the observations of increased chlorophyll a in the treated sewage plumes, we recommend expanding the environmental monitoring program during SWAC operation. The operational monitoring plan must be well resolved temporally and spatially because the way the plume will spread is not understood and is likely to be variable according to changing physical conditions (Petrenko et al, 1998). An increase in nutrient concentrations above the compensation depth will likely result in changes in primary production rates and ultimately in plankton biomass.…”

Geostatistical Prediction of Ocean Outfall Plume Characteristics Based on an Autonomous Underwater Vehicle

“…When taking the kriging variance into account, in the 2m map the plume may be identified by the regions where salinity is less than 35.48psu and in the 4m map by the regions where salinity is less than 35.57psu. The plume exhibits a considerably more complex structure than the compact shape of the classical picture of the buoyant plume and is as patchy as in previous studies [4][5][6]. The small plume-related anomalies in the local salinity of Figures 9 and 10 are evidence of the rapid mixing process.…”

A multi-objective genetic algorithm applied to autonomous underwater vehicles for sewage outfall plume dispersion observations

“…Several tasks for sewage outfall plume dispersion observations in ocean are performed in order to measure the particles' concentration. The observed plume patchiness can be due to one or a combination of factors [1][2][3] which include: variations in currents and stratification during time intervals; internal tides due to the outfall; limitations of sampling in terms of resolution of time and space and inadequate number of critical variables. A rapid sampling is then expected to reduce time and space variability.…”