A simple modelling approach for water quality: the example of an estuarine impoundment.

With the increasing development of water quality standards for all forms of water bodies and all forms of their uses, there is a greater need for models that can predict water quality in relation to these standards. This paper proposes an empirical method based on logistic regression techniques that deliver probabilities that given quality standards are met (i.e. water above or below the given standard). This technique is applied to data from a saline intrusion barrage (River Wansbeck, Northumberland, England) to predict low water quality events on the basis of UK water standards. The approach accurately classifies the overwhelming majority of pollution events that are caused by processes internal to the system. Misclassification can be ascribed to external processes, such as combined sewer outfalls. The general applicability of this method is compared to physically-based models.