FAQs

• Water that originates from rain or storm events. Stormwater can soak into the soil, be stored on the land surface in ponds, puddles and dams, evaporate, or contribute to surface runoff.
• Stormwater can cause problems downstream when peak events cause flooding. It can also be a source of pollution when litter, sediment, nutrients and chemicals are washed into waterways.
• Managing stormwater, minimising hard surfaces along with careful landscaping can help to slow the movement of stormwater and improve environmental outcomes.

A Stormwater Management Plan (SMP) is a strategic planning document which aims to address existing stormwater problems within a catchment, or catchments, and identify opportunities for providing a range of benefits through a multi-objective planning process. This multi-objective planning includes consideration of flood risk, protection of water quality and opportunities for stormwater reuse.

The Stormwater Management Plan will provide the framework for a coordinated, multi-objective approach for the management of stormwater within the study area. It will support catchment scale stormwater planning to ensure adequate consideration of flood mitigation, water quality and reuse opportunities.  

The Stormwater Management Authority (SMA), through the implementation of the Local Government (Stormwater Management) Amendment Act 2007, is charged with the responsibility of working with councils to facilitate stormwater management planning and to allocate state funding to projects in collaboration with Councils and other funding bodies. Its establishment was a key element of an agreement between the South Australian Government and Local Government Association on the management of stormwater within the state. The agreement outlines the responsibilities for stormwater management and aims to support catchment scale stormwater planning to ensure adequate consideration of flood mitigation, water quality and reuse opportunities.

A key element of the SMA’s Strategic Plan is to identify the need for, and then drive the development of Stormwater Management Plans across South Australia. 

The Stormwater Management Authority (SMA) has identified the area encompassing Aldgate, Bridgewater and Crafers as ‘medium’ priority for the development of a stormwater management plan (SMP). The SMA notes that although the area is generally not prone to flooding, stormwater quality is of concern as the area drains to natural watercourses, and ultimately to Mount Bold Reservoir.

While flooding of private property (outside of major creeks) is not a wide-spread issue across the study area, there are a number of specific locations where the capacity of key infrastructure and/or flooding of private property are of concern to the Adelaide Hills Council (Council). The combined effects of future development within the catchment and increases in rainfall intensity, associated with climate change, may exacerbate this flooding in future.

Council has engaged a consultant called Tonkin to prepare a Stormwater Management Plan for the townships of Aldgate, Bridgewater, Crafers and Stirling – all of which are located within the Upper Onkaparinga Catchment. 

Council will engage key stakeholders and the community to ensure they can contribute to the planning and development of the Stormwater Management Plan.

These stakeholders will include:

• Community groups and Businesses in townships and interested community members
• Adelaide Hills Council Elected Members
• Environment Protection Authority 
• Stormwater Management Authority 
• State Emergency Services
• Department Environment and Water - Flood Management Team 
• Hills and Fleurieu Regional Landscape Board

The intent of a stormwater management plan (SMP) is to set out strategies, actions and programs that can be implemented to work towards achieving Council’s objective of “stormwater management, asset and development planning and risk management.”

A SMP seeks to ensure that stormwater management is addressed on a total catchment basis with the relevant natural resources management (NRM) board, various local government authorities and state government agencies responsible for the catchment working together to develop, implement and fund a coordinated and multi-objective approach to the management of stormwater for the area.

The SMP will provide a template for consistent management of stormwater within the town, aimed at addressing existing problems and capitalising on opportunities for providing a range of benefits through multi-objective planning. The plan will be used as the basis for developing budgets and allocating state support funds (matched by the Council) across the study area.

The Stormwater Management Plan (SMP) will be developed in accordance with the Stormwater Management Authority’s Stormwater Management Planning Guidelines (2007), which provides a framework to ensure consistency in the planning and implementation of projects and measures across the state.

The guidelines state that the SMP must:

• Identify the objectives and outcomes for management of stormwater in the catchment, as defined by Council and the Landscape Board.
• Clearly define the area covered by the plan.
• Describe all known existing stormwater assets within the catchment.
• Through the use of modelling, historical records and technical investigations, identify stormwater management problems and opportunities, including flooding risk, water quality and reuse potential.
• Based on the outcomes of the investigations, identify strategies (structural and non-structural) to meet the specified management objectives for the catchment.
• Determine capital and maintenance (including recurring) costs associated with the management strategies and how those costs will be apportioned between councils and government agencies if relevant.
• Assess the benefits to be gained by implementation of the proposed management strategies.
• Prioritise the proposed strategies and identify a timeframe for implementation.
• Assign responsibility for implementing the strategies and meeting any costs.
• Provide a plan for communication / consultation of the strategy.

The process will include a large amount of data collection and analysis, followed by detailed computer modelling to predict the risk of flooding under a range of varying rainfall conditions. These models will be used to produce flood inundation maps, as well as estimating the likely pollutants that are transported within the stormwater runoff. Field work will be undertaken to map the condition of the watercourses within the study area, including identifying the presence of exotic species.

Results of the modelling and analysis will be used to develop a list of management strategies to be developed. These strategies will be tested for effectiveness and the costs for implementation will be estimated.

The study area for this Stormwater Management Plan is located entirely within the Adelaide Hills Council region. It stretches between the Mount Lofty Summit at the western end and the Onkaparinga River passing through Mylor at the eastern end, capturing a total area of approximately 27.8 km2. It covers the full extent of the four townships, from west to east (i.e. upstream to downstream): Crafers, Stirling, Aldgate and Bridgewater.  

The predominant land use within the study area is residential (including rural residential). While these developed areas occupy a large portion of the study area, they are considered low-density and comprise a considerable amount of green space.

• Nuisance or minor local flooding
• Major flooding that puts property at risk
• Stormwater hazards that pose a risk to the safety of people
• Watercourse health issues such as unstable banks or weed infestations.

For any maintenance concerns, such as blocked pits, street sweeping, or drain cleaning, please report them via:

• Email mail@ahc.sa.gov.au
• Complete our online feedback form
• Call (08) 8408 0400
• Post to PO Box 44, Woodside SA 5244
• Visit a Council customer service office

Further information can also be found here: Resident Service Standards and Complaints (ahc.sa.gov.au)