Modelling a residential catchment, an industrial catchment and a catchment under construction to evaluate the quality and quantity of stormwater discharges into a coastal salt water Lake

Abstract

Proposed developments within Lake Macquarie Council area are required by Council to manage their stormwater discharges to protect a local coastal salt water lake. Previous whole of catchment modelling indicated that for a small urbanised catchment near the coastline, council's stormwater quality management targets can be met when between 10 and 80% of the proposed development area is designed to control stormwater. It was also found that the area needed to be controlled reduces with increasing focus on impervious areas. Continuing research and modelling has been conducted focussing on a small residential catchment and an industrial catchment to develop local input parameters for stormwater management design in the catchment area. The recommended input parameters were also utilised in a large mixed catchment to determine if they are applicable on a larger scale. MUSIC was calibrated and validated using on-site collected data. The input parameters calibrated and validated in this modelling exercise have been made available to Lake Macquarie Council for use by those designing stormwater management systems for proposed developments. It was shown that the input parameters are suitable for lot scale, precinct and catchment scale modelling. The results of this modelling may also have application in other catchments.