September 3, 2019
Water Industry Alliance Leading Edge Member, Tonkin, has recently been engaged by the City of Charles Sturt (Council) to prepare a stormwater management plan (SMP) for five major stormwater sub-catchments with a total area of 26 km squared, which will drain into West Lakes in Adelaide, SA. The project, jointly funded by Council and the Stormwater Management Authority (SMA), is part of Council’s commitment to prepare comprehensive and integrated stormwater catchment management plans for all major catchments within their areas to ensure environmentally, socially, economically and efficient management and use of Council’s stormwater resources.
The SMP will utilise the latest methods recommended in Australian Rainfall and Runoff 2019 and will build on significant work undertaken by Tonkin and others within the catchment over the last 20 years. The contents of the final SMP developed during this project will comply with the requirements of the SMA. The SMP will provide greater clarity to the extent of stormwater management related issues within the catchment and will provide Council with a framework for the sustainable management of water resources across the broader catchment.
The first stage of the project, which is currently underway, involves a comprehensive review of available information relating to the management of stormwater in the catchment. As part of the initial investigations, Tonkin is reviewing previous relevant studies that have been done, undertaking an assessment of the soil and ground water conditions, reviewing the environmental values of the receiving environment (West Lakes), and reviewing Council’s GIS data to define all of the stormwater assets within the catchment. An assessment of the potential changes to the level of development in the catchment and potential future climates will also be completed, with a focus on 2070.
Following completion of the initial investigations, Tonkin will undertake hydrologic and 2-D hydraulic modelling to prepare flood maps of the entire study area, taking into account the projected level of development and the likely impacts of climate change. Water quality modelling will also be undertaken to assess the impact of stormwater discharges on the water quality in West Lakes. The engineering models, combined with information provided by Council and other key stakeholders, will be used to define the key stormwater related problems in the catchment. Working with Council and other key stakeholders including the Natural Resources Management Board, Department for Planning, Transport and Infrastruture, Department for Environment and Water SES and users of the lake, Tonkin will develop a framework to guide the development of a set of sustainable stormwater management objectives. The models developed will then be used to scope opportunities to mitigate flood risk, improve water quality and to increase stormwater reuse in the Council area.