Multiregression analysis of the kinetic constants in ephemeral rivers: the case study of the Oreto river.

Profuse efforts have been committed to develop efficient tools to measure the ecological status of the receiving water body quality state. The recurrence to mathematical models as support tools for the receiving water body quality assessment can be an optimal choice. Indeed, mathematical models can allow to build-up the cause effect relationship between polluting sources and receiving water quality. Regarding the river water quality modelling, two different kinds of river can be single out: large and small rivers. In the modelling approach, the main differences between the two types of river are reflected in the model kinetic constants. Indeed, the main quality processes which control and govern the quality state (i.e. de-oxygenation and re-oxygenation process) play a differ rule. As a results, the application of model approaches as well as kinetic constants derived for large river, can lead to wide biases thus misevaluating the river quality state. The paper presents a study where a multiregression analysis was carried out for assessing relationships to be employed for the evaluation of the kinetics constants for small rivers. To accomplish such a goal, the kinetic constants derived by a previous application of a river water quality model applied to a real case study (Oreto river) were used. Such kinetics constants were employed for deriving new multiregression equations for the assessment of the kinetics constants for small rivers.