Georges River Flood Data April 28th - May 1st, 1988

This report details the flood gauging operation undertaken on 30th April, 1988 and\r\npresents the data collected for the Georges River catchment, Sydney.\r\n\r\nThe Georges River catchment area is approximately 960 square kilometres and is\r\nshown in Figure 1.1. The main arm of the river begins its course near the Cataract\r\nDam, and exits into Botany Bay. The main channel is joined throughout its course\r\nby minor streams and creeks. The Woronora River catchment also drains into the\r\nGeorges River.\r\n\r\nThe catchment area comprises a large part of the south western urban area of the\r\ncity of Sydney, and the floods that have occurred in the catchment have at times\r\ncaused significant damage to property.\r\n\r\nTo rationalise future development of the area in the face of potential flood threats,\r\nvarious numerical and physical models have been developed by both the University\r\nof N.S.W. Water Research Laboratory, and the Public Works Department's Manly\r\nHydraulics Laboratory. The success of the models in predicting the flooding\r\ncharacteristics of various flood events depend upon collecting specific flood data\r\nover a series of floods for model calibration and verification. To this end, all known\r\ninformation regarding previous floods has been documented (Ref. 1 and 4), but\r\nthere is a need for more comprehensive flood data, especially for major floods.\r\n\r\nManly Hydraulics Laboratory (M.H.L.) was requested by the Department's Coast\r\nand Rivers (C&R) Branch to co-ordinate and undertake flood monitoring at various\r\nsites over the area which is being modelled. These monitoring sites appear in Figure\r\n1.2. Previous reports (Ref. 1 and 4) detail the results of gauging of earlier floods\r\nundertaken in 1978, 1983 and 1986.\r\n\r\nFlood gauging on the 30th April, 1988 was carried out by personnel from the\r\nDepartment's M.H.L. and C&R.\r\n\r\nThe general extent of the flooding 12 hours after the peak can be seen in Plates 1 4.\r\n\r\nThe current metering lines, flood gauge locations and automatic recorder locations\r\nfrom which data was collected are as follows:\r\ni) Current metering/gauge observations at:\r\n\r\n1. East Hills Footbridge\r\n2. Mountbatten Bridge\r\n3. Lansdowne Bridge\r\n\r\nii) Automatic recorders located at:\r\n\r\n1. Milperra Bridge\r\n2. Cutler Road, Lansvale\r\n3. Scrivener Street, Warwick Farm (* This recorder malfunctioned during the flood event.)\r\n4. Liverpool Weir\r\n5. Prospect Creek, Lansdowne

本报告详述了1988年4月30日开展的洪水测报（flood gauging）作业，并展示了悉尼乔治河汇水区（Georges River catchment）的采集数据。

乔治河汇水区总面积约960平方公里，如图1.1所示。该河干流发源于卡塔拉克特大坝（Cataract Dam）附近，最终注入博特尼湾。干流全程沿途汇入多条小型溪流与河沟。沃罗诺拉河汇水区亦向乔治河汇水。

该汇水区覆盖悉尼市西南城区的大片区域，区内历次洪水均曾对沿岸财产造成严重损失。

为在潜在洪水威胁下合理推进本区未来开发，新南威尔士大学水利研究实验室（University of N.S.W. Water Research Laboratory）与公共工程部曼利水力实验室（Manly Hydraulics Laboratory, M.H.L.）已共同开发了多款数值与物理模型。上述模型对各类洪水过程洪灾特征的预测精度，取决于能否针对多场洪水采集针对性数据以完成模型率定与验证。为此，研究人员已将已知的历次洪水相关资料整理归档（参考文献1与4），但仍需获取更全面的洪水数据，尤其是大型洪水的相关资料。

公共工程部海岸与河流分部（Coast and Rivers Branch, C&R）委托曼利水力实验室（M.H.L.）统筹并开展研究区内各监测站点的洪水监测工作，相关监测站点分布如图1.2所示。此前的报告（参考文献1与4）已详述了1978年、1983年及1986年开展的早期洪水测报成果。

1988年4月30日的洪水测报作业由公共工程部曼利水力实验室与海岸与河流分部的工作人员共同完成。

洪峰出现12小时后的洪水波及范围概况见附图1至4。

本次采集数据所涉及的现行测流断面、洪水监测站点及自动记录仪布设点位如下：
i) 测流/水位监测点位：
1. 东山希尔步行桥（East Hills Footbridge）
2. 蒙巴顿大桥（Mountbatten Bridge）
3. 兰斯当大桥（Lansdowne Bridge）
ii) 自动记录仪布设点位：
1. 米尔佩拉大桥（Milperra Bridge）
2. 兰斯维尔卡特勒路（Cutler Road, Lansvale）
3. 沃里克农场斯克里夫纳街（Scrivener Street, Warwick Farm）* 该记录仪在本次洪水事件中发生故障。
4. 利物浦堰（Liverpool Weir）
5. 兰斯当展望溪（Prospect Creek, Lansdowne）