5.47. Once the scenarios have been developed, the corresponding assessments should be carried out. This is commonly undertaken using assessment models. An assessment model will be developed from the following components: @@- A conceptual model, which is a representation of the behaviour of the system that is suitable for the particular purpose of the assessment as defined in the context for the assessment: The conceptual model provides a description of the components of the system and the interactions between these components. It also includes a set of assumptions concerning the geometry of the system and the chemical, physical, hydrogeological, biological and mechanical behaviour of the system, consistent with the information and knowledge available. @@- A mathematical model, which is a representation of the features and processes included in the conceptual model using mathematical equations: The representation can vary in scope and complexity depending on the level of understanding of the phenomena or processes being modelled and the information and data available. The mathematical model can be used for performing quantitative analyses.@@- A computer code, which is a software implementation of the mathematical model that facilitates performance of the assessment calculations: The computer code may include numerical schemes for solving the equations in the mathematical model.