River Flood Maps (FRM_FH_RIVER_VELOCITY_L)

These maps have been produced to meet SEPA’s duty to publish flood hazard maps as set out in the Flood Risk Management (Scotland) Act 2009. The maps show where there is a risk of flooding from the sea, from rivers and from surface water.The following probabilities are available for river flooding: - High - 10 year return period - Medium - 200 year return period - Low - 1000 year return period and 200 year return period plus climate change using the UKCP09 high emissions scenario for the 2080s.The river hazard maps show (where available): - Flood extent - Flood depth - Flood velocities where appropriate. The climate change scenario has been defined by United Kingdom Climate Projection 2009 (UKCP09) predictions for 2080 high emissions 95%ile predictions. Velocity is presented, where appropriate; this is determined by considering the confidence in input data, modelling method and impact. It is currently represented as one of four bandsMedium and low probability flood events were selected for consistency with return periods used in Scottish Planning Policy, whereas the high probability was chosen as it is reflective of observed events experienced over the last few decades.本批洪水危险性地图的编制，旨在履行苏格兰环境保护局（Scottish Environment Protection Agency, SEPA）依据《2009年洪水风险管理（苏格兰）法案》所规定的发布洪水危险性地图的法定职责。这批地图展示了海洋、河流以及地表径流引发的洪水风险区域。针对河流洪水，共提供以下不同概率等级的洪水危险性数据： - 高概率：10年一遇重现期 - 中概率：200年一遇重现期 - 低概率：1000年一遇重现期，以及基于2080年代英国气候预估2009（UKCP09）高排放情景的200年一遇重现期叠加气候变化影响的场景。 河流洪水危险性地图（如可获取）将展示以下信息： - 洪水淹没范围 - 洪水水深 - 适当时机的洪水流速。 本次采用的气候变化情景，基于英国气候预估2009（UKCP09）针对2080年代高排放场景下的95%分位数预测结果设定。适当时机将展示洪水流速，该流速的确定需综合考量输入数据可信度、建模方法以及影响评估结果。目前流速被划分为四个等级之一。本次选取中、低概率洪水场景，是为了与苏格兰规划政策中采用的重现期标准保持一致；而高概率场景的选取，则是为了反映近数十年来实际观测到的洪水事件特征。