Design of discharge policies for multiple effluent sources and returning pollutants scenarios in a branching estuary

Validity of a moving boundary finite element model for salt intrusion in a branching estuary

“…Bikangaga and Nassehi [10] have proposed a number of discharge policies for effluent release in the estuary considering both single and multiple sources. Passone et al [12] have enhanced the accuracy of these discharge programmes through inclusion of the effects of returning pollutants and flow reversal in the estuary. However, moving boundary models for the estuary to look specifically into the effects of its branches are rare in the literature.…”

“…These will enable development of more realistic effluent discharge policies for the estuary. The Upper Milford Haven estuary falls in a general class of estuary known as 'ria' and is characterised by a network of narrow and branching channels with a V-shaped cross section [12,30]. The width to depth ratio is considered to be moderate.…”

“…In the present case, the simulations are carried out with initial values of discharge equal to zero, depths equal to the elevation of the bed at each node and salt concentration equal to 25 ppt. Similar initial conditions for these variables were also used by Nassehi and Williams [28], Bikangaga and Nassehi [10], Kafai and Nassehi [19] and Passone et al [12] for studying salinity/contaminants distribution in the Upper Milford Haven estuary.…”

“…(see, Fig. 1 and [12] for details) and choosing a range of values for the friction coefficient, i.e., 0.01-0.05. Then we optimise the friction coefficients by comparing observed and computed water levels in the estuary.…”

“…The technique eliminates a number of limitations of the existing schemes for moving boundary problems and is capable of generating computationally efficient results, as demonstrated later. One important practical application of the inclusion of the moving variable domains in the simulation tools for the estuarine transport processes [10][11][12] is that they allow more accurate design of effluent discharge policies for estuaries. The validity of the present scheme is tested against field measurements for salinity levels in the Upper Milford Haven estuary, a branching estuary in Wales, UK.…”