DesignFlow

Stormwater Asset Management
WSUD Asset Management - Needs and Scope
Client: Healthy Waterway Partnership
Good design is important but must be coupled with effective construction, establishment and ongoing management in order to realise the potential benefits of that design. This is particularly important for vegetated stormwater management systems such as bioretention systems, wetlands and swales. A number of industry stakeholders, including local government and private consultants, have highlighted the lack of appropriate guidance and protocols on construction, establishment, asset transfer and ongoing maintenance as a major barrier to the successful implementation of water sensitive urban design.
The policy position in Queensland means that stormwater management is now, or will be in the near future, an element of all new development and infrastructure delivery. Evidence from local authorities indicates there is a wave of WSUD infrastructure making its way through the development approval and construction process. This 'WSUD Asset Wave' will soon make its way into Council, or other, ownership for operation, management and maintenance. DesignFlow was commissioned to identify the: The work was based on a comprehensive stakeholder consultation exercise with both high level managers through to the on-ground personnel completing maintenance work. The findings of the assessment were used to establish a project plan to deliver a comprehensive range of guidelines and tools that will assist and guide the management of WSUD assets from handover to ongoing maintenance (refer guidelines below).

 
Melbourne Water Maintenance Guidelines
Client: Melbourne Water
These guidelines were developed in close collaboration with Melbourne Water. The guidelines form part of Melbourne Water's Asset Management Package for stormwater treatment systems to assist Councils plan and implement best practice management of stormwater treatment systems. A broad range of Council stakeholders were consulted during the guideline development to ensure the content is relevant and presented in an accessible way. The guideline includes comprehensive asset inspection and maintenance forms that can be used by Council staff and maintenance contractors.  
Melbourne Water Maintenance Guidelines  

 
Maintaining WSUD Assets Guidelines
Client: Healthy Waterway Partnership
DesignFlow were the principal authors of the maintenance guidelines. The document provides practical and standardised maintenance advice to enable planning for and completion of maintenance of sediment basins, wetlands, bioretention systems and swales. The document defines performance indicators and provides recommended frequencies of inspection and routine maintenance tasks, practical reference tables, checklists and forms to use during inspections and maintenance. The document is the first of its kind in Australia and represents a starting point for everyone associated with managing WSUD assets.
 
Maintaining Vegetated Stormwater Assets  

 
Rectifying WSUD Assets Guidelines
Client: Healthy Waterways Partnership
DesignFlow were the principle authors of the rectification guidelines. The document provides guidance for rectifying common problems in sediment basins, swales, bioretention systems and constructed wetlands. The guideline addresses common problems in under-performing or failing systems, steps for identifying the cause of the problem, options available to rectify the problem, how to determine if a system is beyond repair and options for how to deal with systems that cannot be rectified.
 
Deemed to Comply  

 
Handing Over WSUD Assets Guidelines
Client: Healthy Waterways Partnership
DesignFlow were the authors of the asset handover guidelines. The document provides guidance on how to transfer vegetation stormwater assets from the constructing party, typically the developer, to the long-term owners and managers of the asset, typically the local authority or body corporate/manager, so that owners inherit assets that are functional properly and are meeting the design intent. It provides numerous handover options, information, processes and checklists to assist with each stage of the handover process. It covers swales, bioretention systems, constructed wetlands and sediment basins.
 
Deemed to Comply  

Gold Coast Stormwater Management Condition Assessments, QLD
Client: Gold Coast City Council
Gold Coast City is one of Australia's most rapidly growing areas. Accompanying this growth is development pressure and an increased population. In response to these pressures, Council has fostered and encouraged the use of best practice stormwater management systems which minimise the impact on waterways by removing pollutants and reducing the change in stormwater flows. As a consequence of encouraging WSUD through its planning scheme, Council now owns and maintains approximately 320 Council vegetated stormwater management systems. These systems have been recorded in Council's data and GIS register. The collection of this data has occurred through various approaches meaning the quality of the data is variable. Review of the existing stormwater management database by Council found the data does not reflect contemporary thinking in terms of water sensitive urban design and requires restructuring to allow informed decisions to be made around maintenance activities. DesignFlow were commissioned by Council to: A comprehensive and rapid condition assessment method was developed for the project which can be readily applied in any location.
 

 
Edinburgh Gardens Raingarden Rectification
Client: Melbourne Water/City of Yarra
DesignFlow was engaged by Melbourne Water to develop a rectification plan for the poor-performing Edinburgh Gardens raingarden. A holistic assessment by DesignFlow's engineers and ecologists revealed a number of design and construction issues for the raingarden, diversion infrastructure and gross pollutant trap. DesignFlow worked with all stakeholders to develop and implement a practical and cost effective rectification plan. Rectification works ensure the raingarden receives adequate flows and is protected from gross pollutants, the filter media has an appropriate drainage rate and untreated flows do not bypass the filtration system and enter the reuse tank.  

Edinburgh1  

 
Boroondara Asset Audit
Client: City of Boroondara
The construction and ongoing management of stormwater treatment assets is critical to ensure that they perform as intended and deliver the water quality benefits expected of them. Boroondara City Council engaged DesignFlow to undertake an audit of their existing WSUD assets which range from small tree pit systems through to large scale bioretentions. The audits looked at available design details and the corresponding on ground condition. An assessment was made on factors ranging from the planning, design, construction and maintenance of systems to assign condition scores and prioritise a range of rectification actions. Through workshops and on site field audit participation we were able to educate the relevant Council personnel on the critical aspects of system function to assist with future implementation and management.  

 
Sandhurst Crescent Sediment Basin Rectification
Client: Gold Coast City Council
Since construction, the sediment basin and flood storage at Sandhurst Crescent has proved difficult to maintain and has experienced scour and excessive weed growth. As a result, the system does not operate in accordance with the design intent and requires rectification. DesignFlow were commissioned by Gold Coast City Council to review the existing system and identify a practical rectification solution which allows cost effective management. A range of rectification options and associated costs were identified by DesignFlow, with Council with the final solution selected via a simple workshop session at the site.
 

 
Logan Rectification and Maintenance Advice
Client: Logan City Council
Council have recently initiated a project which will define the resource requirements and costs for rectifying and maintaining bioretention systems, swales and wetlands. It is based on case study sites where certain sites have been selected for rectification and maintenance. Council will carefully log all costs and resources required to complete this work. DesignFlow assisted Council select the case study sites, provided conceptual rectification advice and provided inspections forms for the purpose of maintenance.
 

 
Southport Broadwater Parkland WSUD Maintenance Advice
Client: Gold Coast City Council
Council have been actively managing the high profile wetland located in Southport Broadwater Parkland. A major management issue associated with the wetland is the large number of swamp hens which inhabit the wetland in unnaturally large numbers due to the available food in the parkland. This has resulted in a significant portion of the wetland vegetation being damaged. DesignFlow have been providing advice to Council regarding the management of the hens and re-establishment of the wetland vegetation.