Flood — Awareness — Overland Flow — Overall — 1 Percent Annual Chance

This dataset, created in June 2013, provides an indication of areas subject to overland flow flooding inside the Brisbane City Council local government area. The overall overland flow layer consists of the 1% Annual Exceedance Probability (AEP) (100 year Average Recurrence Interval (ARI)) flood extent sourced from the Citywide Creek and Overland Flow Path mapping study (GHD, 2017). High impact area: In high impact areas, overland flow is almost certain to occur during a single lifetime (70 years). An event of this size or larger has a 5% chance of occurring in any year. The overland flow is generally unsafe for people, vehicles and buildings. Medium impact area: For the majority of medium impact areas, overland flow is very likely to occur during a single lifetime (70 years). An event of this size or larger has a 2% chance of occurring in any year. The overland flow is generally unsafe for people, vehicles and buildings, however these hazards are experienced less frequently than in high impact areas. Low impact area: For the majority of low impact areas, overland flow is likely to occur during a single lifetime (70 years). An event of this size or larger has a 1% chance of occurring in any year. The overland flow is generally safe for people, vehicles and buildings; however, certain areas can experience greater hazards.本数据集于2013年6月编制完成，用于标识布里斯班市议会（Brisbane City Council）管辖范围内易发生地表径流洪水的区域。整体地表径流图层采用了源自全市溪流与地表径流路径测绘研究（GHD，2017）的1%年超越概率（Annual Exceedance Probability, AEP，即100年平均重现期（Average Recurrence Interval, ARI））洪水淹没范围数据。高影响区域：该区域内，地表径流在单个人类生命周期（70年）内几乎必然发生。此类及同等或更大规模的洪水事件，每年发生概率为5%。该区域的地表径流通常会对人员、车辆及建筑物构成安全威胁。中影响区域：该区域内的多数地段，地表径流在单个人类生命周期（70年）内极有可能发生。此类及同等或更大规模的洪水事件，每年发生概率为2%。该区域的地表径流通常同样会对人员、车辆及建筑物构成安全隐患，但灾害发生频率低于高影响区域。低影响区域：该区域内的多数地段，地表径流在单个人类生命周期（70年）内大概率发生。此类及同等或更大规模的洪水事件，每年发生概率为1%。该区域的地表径流通常对人员、车辆及建筑物较为安全，但部分区域仍可能遭遇较高等级的灾害风险。