Heron Park to be sole research site
UWA and the Task Force have decided to focus on Heron Park as their primary field site, rather than utilise several sites as first planned. They believe Heron Park to be the ideal study site and plan to continue monitoring as different development activities (i.e. utilities, drainage, road construction, landscaping and house construction) roll out across the site. Continuing for a second season at Heron Park will also allow a larger range of storms to be monitored.
The focus of this research is currently on the collection of winter rainfall and sediment transport data. Additional storm monitoring data from 2 additional storm events have been captured since October 2017.
Quantifying and modelling TSS
Fraser’s work continues to focus on quantifying the TSS concentration present upstream and downstream of various construction activities and then modelling the TSS discharge caused by those activities per unit of area.
The fieldwork methodology that was developed was to record water level and turbidity observations at 5-minute intervals at each monitoring station. Water level has been recorded so the hydrodynamics of the channel can later be modelled to determine flowrate in the channel.
Turbidity has been used as a surrogate parameter for TSS concentration. TSS concentration and flowrates in the channel will be used to determine the mass of TSS coming into the channel carried by stormwater runoff between the two monitoring stations.
Laboratory analysis/sediment transport model
Laboratory analysis of stormwater samples has involved water samples being analysed for TSS concentration, using vacuum filtration as per the standard method 2540 D.
UWA’s sediment transport numerical model will allow them to test different scenarios at different sites (e.g. different soil types, wind regimes, housing types).
Results and conclusions to date
The emerging relationship between TSS and turbidity has been analysed. Clear trends can be seen in the relationship between TSS and Turbidity however more data needs to be collected in conditions where the turbidity is above 200 NTU.