Integrating Water Quality Models in the High Level Architecture (HLA) Environment

HLA (High Level Architecture) is a computer architecture for constructing distributed simulations.It facilitates interoperability among different simulations and simulation types and promotes reuse ofsimulation software modules. The core of the HLA is the Run-Time Infrastructure (RTI) that providesservices to start and stop a simulation execution, to transfer data between interoperating simulations, tocontrol the amount and routing of data that is passed, and to co-ordinate the passage of simulated time amongthe simulations. The authors are not aware of any HLA applications in the field of water resourcesmanagement. The development of such a system is underway at the UFZ – Centre for EnvironmentalResearch, Germany, in which the simulations of a hydrodynamic model (DYNHYD), eutrophication model(EUTRO5) and sediment and micro-pollutant transport model (TOXI5) are interlinked and co-ordinated bythe HLA RTI environment. This configuration enables extensions such as (i) “cross-model” uncertaintyanalysis with Monte Carlo Analysis: time synchronisation allows EUTRO5 and TOXI5 simulations to bemade after each successive simulation time step in DYNHYD, (ii) information transfer from EUTRO toTOXI to compute organic carbon fractions of particulate matter in TOXI, (iii) information transfer fromTOXI to EUTRO to compute extinction coefficients in EUTRO and (iv) feedback from water qualitysimulations to the hydrodynamic modeling.