Developing a conceptual model for water accounting in peri-urban catchments

摘要: Water accounting, ie identifying, quantifying and reporting information of water flow in a system, is the first step towards formulating productive and sustainable water management strategies in a region. This requires a significant effort of monitoring, collecting and modelling hydro-meteorological information over both spatial and temporal scales. A number of catchment water balance models developed in Australia and overseas are capable of estimating runoff, evapotranspiration, and streamflow generated from rainfall received in a catchment. However, most existing catchment water balance models do not account for potable water supply, wastewater discharges and surface and groundwater extractions, and yet these components of surface water cycle significantly modify streamflow in peri-urban catchments such as the South Creek catchment in Western Sydney. The South Creek catchment, the main focus of this study, covers an area of around 625 km2 in gently undulating plains and low hills of Western Sydney. It is a typical example of a peri-urban catchment with urban development over nearly 20% of the land area, and agriculture activities over nearly 17% of the land area. The urban areas in the catchment are serviced with potable water supply from dams outside the catchment, and there are five sewage treatment plants which discharge treated effluent into the South Creek and its tributaries. There are also annual access entitlements to extract water from surface water and groundwater sources mainly for irrigation purposes.In this paper, we describe the development of a simple conceptual water balance model to account for rainfall, runoff …