RFI - Attachment F - Engineering Report

Evaluation of Gully Pit Inlet Litter Control Systems– Brisbane City Council and Gold Coast City Council


                3. TEST RESULTS AND OBSERVATIONS



                3.1      36mm horizontal bar.


                Testing was undertaken to determine the effect on hydraulics and capture
                performance of the lip in line gully inlet with a bar placed horizontally
                across the inlet. The modified litter sample was used for this test and was
                added to the gutter at an approach flow of 25L/s. The flow rate was
                increased up to 320L/s and amounts of litter retained on the inlet were
                observed at each increment. “Sag” results, calculated as depth at inlet, are
                shown in Figure 3.


                Test results and observations:


                Litter Capture Performance.
                The table below shows percentages of litter added that is retained on the
                grate or by the bar for varying approach flow.

                               SLOPE            APPROACH             % LITTER
                                                 FLOW L/s            RETAINED
                                                    25                  100
                                  1%                85                  88
                                                   243                  82
                                                   320                  76

                                                    25                    88
                                  4%                60                    82
                                                    120                   76
                                                    180                   18
                                                    320                   18

                                                    25                    94
                                 12%                60                    30
                                                    240                   30
                                                    320                    6




                Urban Water Resources Centre               7             University of South Australia