Flood — Awareness — River

This dataset, created in June 2013, provides an indication of the likelihood of a flood occurring from Brisbane River inside the Brisbane City Council local government area. This layer contributes to the overall Flood Awareness Mapping for Brisbane City Council. River flooding happens when widespread, prolonged rainfall occurs over the catchment of a river. As the river reaches capacity, excess water flows over its banks, causing flooding. River flooding can occur hours after the rain has finished, depending on the location within the catchment. The extent of river flooding depends on the severity of the weather and the capacity of the river among other things. The impact on a home depends on how close it is to the river and the proximity to low lying areas. There are four different river flooding likelihood areas in Flood Awareness Map, namely High, Medium, Low and very low. The river flood High likelihood layer consists of the 5% Annual Exceedance Probability (AEP) (20 year Average Recurrence Interval (ARI)) flood extent. The extent was sourced from Brisbane River Catchment Flood Study (BMT, 2017) which was commissioned by State Government. The river flood Medium likelihood layer consists of the 1% AEP (100 year ARI) flood extent (outside high likelihood area). The extent was sourced from Brisbane River Catchment Flood Study (BMT, 2017) which was commissioned by State Government. The river flood Low likelihood layer consists of the 0.2% AEP (500 year ARI) flood extent (outside high and medium likelihood areas). The extent was sourced from Brisbane River Catchment Flood Study (BMT, 2017) which was commissioned by State Government. The river flood Very Low likelihood layer consists of the Extent of the 0.05% AEP (2000 year ARI) flood extent (outside high, medium and low likelihood areas). The extent was sourced from Brisbane River Catchment Flood Study (BMT, 2017) which was commissioned by State Government.本数据集于2013年6月编制，用于表征布里斯班市议会（Brisbane City Council）辖区内布里斯班河发生洪水的可能性，是布里斯班市议会整体洪水风险意识地图（Flood Awareness Mapping）的组成部分。 河洪通常因流域内出现大范围持续性降雨引发：当河道水位达到承载上限时，多余水量漫过堤岸，进而造成洪水。根据流域内位置的不同，洪水可能在降雨结束数小时后才会爆发。河道洪水的影响范围取决于气象灾害强度、河道容载能力等多重因素；而住宅受洪水影响的程度，则与其与河道的距离以及邻近低洼区域的程度直接相关。 本次洪水风险意识地图中共包含四类河洪可能性分区，分别为高、中、低以及极低概率区。高概率河洪图层对应年超越概率（Annual Exceedance Probability, AEP）5%（即平均重现期（Average Recurrence Interval, ARI）20年）的洪水淹没范围，该数据源自昆士兰州政府委托开展的《布里斯班河流域洪水研究》（BMT, 2017）；中概率河洪图层对应年超越概率1%（平均重现期100年）的洪水淹没范围（不含高概率区），数据同样源自上述研究报告；低概率河洪图层对应年超越概率0.2%（平均重现期500年）的洪水淹没范围（不含高、中概率区），数据来源同上；极低概率河洪图层对应年超越概率0.05%（平均重现期2000年）的洪水淹没范围（不含高、中、低概率区），数据来源亦为上述《布里斯班河流域洪水研究》（BMT, 2017）。