Complex OSD Systems at Parramatta, NSW
The files for this example, UPRCT Example 1 - Full Unsteady.drn and UPRCT Example 1a - Full Unsteady.drn are located in the folder C:\ProgramData\Drains among the Full Unsteady examples. If this folder is hidden, in File Explorer select the 'View' tab and tick the 'Show Hidden Items' box to make it visible.
The first example models an OSD system of the type at the top of the figure below, which was introduced in the 2005 On-Site Stormwater Detention Handbook of the Upper Parramatta River Catchment Trust. This has two orifice outlets in parallel, connecting to a common outlet pipe.
Accurate modelling can only be done with the special weir and orifices that are provided with the Full unsteady hydraulic model. Only one storage needs to be modelled. The results for the parallel outlets are shown below. With the ARR 2019 ensembles, the ones shown are all from different storms.
The results for the basin water levels are complex:
To examine events in more detail, we can select individual storms using the procedure described in Example S2. The file UPRCT EXample 1 - Full unsteady with individual storms.drn contains selected storms, and you can examine inflow - outflow hydrographs.
The associated example UPRCT Example 1a – Full unsteady.drn includes a simple re-arrangement that models orifice outlets in series, as shown at the bottom of the sketch of the basins. The results from this are shown in the output below.
Example P18 Parramatta Complex OSD.html
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