Surface Water Flood Maps (FRM_FH_SURFACE_WATER_VELOCITY_L)

The following probabilities are available for surface water flooding: - High - 10 year return period - Medium - 200 year return period - Low - 200 year return period plus climate change using the UKCP09 high emissions scenario for the 2080s.The surface water hazard maps show (where available): - Flood extent - Flood depth - Flood velocities where appropriate. 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 bandsThe climate change scenario has been defined by United Kingdom Climate Projection 2009 (UKCP09) predictions for 2080 high emissions 95%ile predictions. Medium 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.本次提供的地表洪水（surface water flooding）概率分级如下： - 高概率：重现期10年一遇 - 中概率：重现期200年一遇 - 低概率：基于2080年代英国2009年气候预测（UKCP09）高排放情景下的气候变化修正的200年一遇洪水 地表洪水危险地图包含以下内容（如可获取）： - 洪水淹没范围 - 洪水水深 - 适宜场景下的洪水流速 流速的展示需结合实际场景判定，其判定依据为输入数据可信度、建模方法与影响程度，当前将流速划分为四个等级进行呈现。 本研究采用的气候变化情景，基于英国2009年气候预测（UKCP09）中针对2080年代高排放情景的95%分位数预测结果设定。 中、低概率洪水事件的选取，为与苏格兰规划政策中采用的重现期标准保持一致；而高概率洪水事件的选取，则参考了近数十年间已观测到的实际洪水事件特征。