Hydro Planner - a linked modelling system for water quantity and quality simulation of total water cycle

This paper describes a software tool called Hydro Planner, being developed as part of CSIRO's Water for a Healthy Country National Research Flagship Program. The main purpose of Hydro Planner is to enable urban water planners and managers to adopt a systems approach to obtain an improved understanding of how water, wastewater and stormwater systems interact with each other and with natural water systems in terms of water, contaminant and nutrient flows at city and regional scale. Hydro Planner can assist development of regional water allocation, river management, land development and urban water supply/demand strategies by allowing practitioners to assess implications of a variety of water management and land development options by considering the influence of factors such as climate change, population growth and technological changes. The aim of this paper is to describe conceptual design and implementation aspects of Hydro Planner. The modelling approach adopted in Hydro Planner utilises E2 model integration framework (www.toolkit.net.au/e2) to link models that can simulate various components of total water cycle in an urban context. The component models included in Hydro Planner support continuous simulation of runoff and constituent generation from water supply and urbanised catchments, urban and environmental water needs, supply system behaviour such as reservoir storage levels and demand shortfalls and routing of both flows and constituents through a stream network down to the tidal limits in estuaries. Hydro Planner is being developed with a view toward generic integration of these components. Our aim is to provide an integrated modelling system of the total water cycle in any given urban area through linking of component models of a complexity appropriate to the questions being addressed and the available data and knowledge. Hydro Planner consists of seven modules: (1) catchment module - supports linking of models that can simulate constituent and runoff generation processes from supply catchments; (2) water supply module - supports linking of models that can simulate water supply system behaviour; (3) consumption module - supports linking of models that can simulate urban water consumption; (4) stormwater module - supports linking of models that can simulate stormwater and associated constituent generation and routing process; (5) wastewater module - supports linking of models that can simulate wastewater and associated constituent generation and routing processes; (6) receiving water module-supports linking of models that can simulate flow and constituent routing through a stream network; and (7) integration module - supports translation and computation of input/output data between modules and the Graphical User Interface. The E2 framework contains component models needed for the catchment and receiving water modules. Hydro Planner adds models to support the remaining modules. Implementation of Hydro Planner is currently in progress. At present, catchment, water consumption, water supply and receiving water modules are nearing completion. The water consumption module provides functionalities to access Water Services Association's End Use Model and the water supply module provides functionalities to communicate with the REALM model. The catchment module supports a number of rainfall/runoff models and constituent generation models. The receiving water module supports a number of routing models. Currently, a case study is underway using Benalla water supply system, to test functionalities of catchment, water consumption, water supply and receiving water modules of Hydro Planner. The test case study is used to assess: potential impacts of 2030 climate change scenarios; and the potential impacts of changing end water use behaviours. The test case considers the effect of climate change, population growth and various demand and supply side management options on the supply system performance such as system yield and the quality of water in Ryans Creek.