Client: Centrum Town Planning
Afflux Consulting was asked by Gilmac Pty Ltd to prepare a stormwater management plan suitable for the development of a hay storage and processing facility on Charlton – St Arnaud Rd, St Arnaud. The investigated discussed the impact of development on flow regimes and outlines stormwater management strategies to reduce flood risk, manage stormwater quality and avoid environmental degradation to the region. It demonstrated that with careful attention to stormwater management, this development can meet North Central CMA and Council requirements and proceed to the next stages. Specifically, this report provided advice on:
- Site Hydrology – Applying Australian Rainfall and Runoff (ARR2016) standards.
- Flood Safety – TUFLOW modelling to demonstrate likely flood impacts.
- Water Quality requirements.
- Drainage capacity checks.
- Best management practice stormwater targets.
The site was subject to large external catchments which had not previously been mapped.
Various hydrological methods were used to estimate peak flows. The results showed that flows expected through the site ranged from 35.4 – 98.2m³/s. RORB model was ultimately reconciled to the RFFE peak flow of 73.65m³/s and applied to the TUFLOW modelling. The resulting engineering items were recommended:
- The development to allow external flows to pass through the site.
- Swale for drainage and nutrient treatment. To be located along the northern and southern facility of ~2000m.
- Facility be placed 300mm above the flood levels as defined in the report.
Key Features and Innovations:
- Minimising the impact of a large industrial facility on the existing environment and flow regime.