Optimal Stormwater audit stormwater quality and water sensitive urban design (WSUD) assets and stormwater harvesting infrastructure. Optimal have championed the need for auditing to benefit the industry and are sharing the outcomes through industry engagement, publications and training.

Auditing – Gross Pollution Traps, Trashracks and all Proprietary Devices

Optimal’s auditing team has extensive knowledge and understanding of gross pollution traps, trash racks, sediment traps, media filters, oil & grit separators, baffle traps, pollution nets, booms, basket & bags ie all proprietary device and soft engineered or WSUD assets.. Based on decades of product development, design, extensive field work and technical assessment we understand the strengths and weaknesses of these assets and provide unique insights on how to improve performance, optimise operation and environmental outcomes.

Through our auditing we identify asset condition, specification and rectification works needed to improve performance and optimise operating regimes to ensure best value. Often reasons for lack of performance can be readily identified and rectification carried.
Physical auditing is complimented with catchment mapping, characterisation and pollution modelling (MUSIC). Actual performance data such as weight dockets are compared with pollutant load estimates and gaps analysed.
Armed with valuable information and data customers feel empower with make better choices when planning for future water quality projects.

Information collated and questions answered in the audit includes:

  • Assets type and model
  • Asset specification and pollution storage volumes
  • Operation and maintenance, needs for monitoring, and triggers for maintenance
  • Performance expectation, ie how much should be collected and expected cleaning frequency
  • GPS positioning as well as detailed location information, and photos
  • Is the GPT or asset correctly specified eg oversized, undersized and suitable for the application
  • Do you know if your GPTs are actually operational (they can be non-operational before cleaning and non-operational after cleaning)
  • Do you have GPTs that are cleaned once or twice a year, but you don’t know if this is enough
  • Do you have sites with flooding, surcharging, litter complaints, odour issues, vermin problems, etc.
  • We can provide capacity building for Councils specific to their own devices if desired.

Optimal Stormwater understand operational and maintenance needs for stormwater infrastructure. Through our audit work we are able to tailor operation and maintenance for a whole of LGA or development for the best spend.




Auditing – Stormwater harvesting infrastructure

Optimal Stormwater provide physical, technical, and operational and process proving auditing of stormwater, groundwater and rainwater harvesting projects. Our operations teams conduct site investigations auditing of mechanical, process, electrical, automation and mechanical infrastructure.

If you have operational problems, we will identify the root cause and provide options and recommendation.

Most stormwater harvesting schemes include gross pollution traps or pollution exclusion offtakes. These critical assets need to be included in the audit because if these fail the scheme will fail prematurely.

Many harvesting projects we are engaged to audit require works. Deficiencies, rectification and optimisation of treatment process, equipment and operation will be reported, costed and implemented.

Auditing water quality through sampling and lab or local analysis to understand the process performance is also provided. Diagrams, photo graphic records, concepts and detailed advice accompanies our audit reports.

We are familiar with the governance and regulatory requirements for recycled water and will report level of compliance in relation to public health and environmental health. Where projects are ‘non-compliant’ or unsafe we will advocate upgrades to achieve water quality targets.
Plants will be recommissioned and new management and testing plans introduced. Water balance modelling is carried also carried out using metered data to calibrate to report against sustainability targets. Detailed reporting, risk assessment and process optimisation plans are prepared for each scheme
Based on auditing of over 40 stormwater harvesting schemes it is evident that the stormwater industry needs on-going training and support to develop more robust projects. Optimal is committed to supporting the industry transition to a more holistic understanding of the nature of sustainable stormwater harvesting.

Our auditing work is complimented by our other capabilities including operation, maintenance and design and construction of stormwater harvesting projects.

Auditing – WSUD and Waterways

Optimal Stormwater have the capability and equipment to audit waterways, ponds, wetlands, biofiltration and other water sensitive urban design assets. Much of our auditing of ‘structural assets’ requires visits to waterways so we value add our work with observation and recording of issues noted within waterways, ponds and biofiltration.

With increasing urbanisation waterways, creek and constructed WSUD assets are under enormous pressure and need to be audited, monitored and rectified if the intended environmental benefits are to be realised.

We have adopted the latest guideline for auditing of biofiltration including soil sampling and hydraulic conductivity (hc) testing. Our hc test rigs are setup within the filter and results used to calculate and report filtration rate.

Soil sampling is conducted and lab analysis and varying layer depth taken to understand the migration and capture performance for target pollutants. Improvements for the filter including amelioration of soils, landscape maintenance and flow management and improved gross pollution controls are reviewed.

Beyond this detailed analysis using the OEH creek rapid assessment methodology can be carried out and environmental health reported. Water quality (physical and chemical) are conducted. Creek stability, erosion hot spots and risk to utilities and private property are also on the radar during the audit.