Far field modeling of the Mamala Bay outfalls

The results of far field modeling of the wastefield formed by the Sand Isla nd, Honolulu, ocean outfall are presented. A far field model, FRFIELD, was coupled to a near field model, NRFIELD. The input data for the models were long time series of oceanographic observations over the whole water column including currents measured by Acoustic Doppler Current profilers and densi ty stratification measured by thermistor strings. Thousands of simulations were made to predict the statistical variation of wastefield properties aro und the diffuser. It was shown that the visitation frequency of the wastefi eld decreases rapidly with distance from the diffuser. The spatial variatio n of minimum and harmonic average dilutions was also predicted. Average dil ution increases rapidly with distance. It is concluded that any impact of t he discharge will be confined to a relatively small area around the diffuse r and beach impacts are not likely to be significant. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.