Modelling in-stream water quality in LOIS

The requirements of the Land–Ocean Interaction Study (LOIS) to model a large number of river systems are considered and an approach outlined that is compatible with data availability and LOIS objectives. The functionality of software to assist data preparation and model application is discussed and compared with the existing QUASAR model. The underlying rationale behind the development of a new software suite, QUESTOR, is described. As an example, the application of QUESTOR to the modelling of the River Wharfe is presented. This includes the method used to define the extent of the network to be modelled and the ways in which tributaries, industrial discharges and abstractions were to be represented. Model calibration procedures are discussed and model validation results presented.