Integrating Northern Victoria's Daily Time Step Tributary Salinity Models

The Murray-Darling Basin Commission's (MDBC) Basin Salinity Management Strategy (BSMS) relates the mobilisation of salt from the landscape to the salinity levels in the rivers of the basin, evaluating salinity over a 25 year benchmark period. Five existing daily salt and water balance models of the Goulburn-Broken, Campaspe, Upper Loddon, Wandella Creek and Kerang Lakes systems have recently been revised and extended to cover the latest benchmark period. These models provide daily flow and salinity inputs to the MDBC's River Murray models. They have been used to establish current river salinity conditions and can be used for a wide range of possible future scenarios. These models previously existed as five stand alone models that had to be run in a complicated sequence. This paper describes the process of integrating three of the five models, greatly improving model interactions and significantly reducing run times. This Goulburn-Broken-Campaspe-Loddon model is now the largest daily flow and salinity REALM model ever built. In an interlinked river system such as in Northern Victoria, the daily models must also communicate in a specific sequence with River Murray models and the monthly Goulburn Simulation Model (GSM), which is used to assess Victoria's Cap compliance. As part of this process, daily model behaviour was reconciled against the monthly GSM and historical River Murray model inputs.