Surface Water Flood Maps (FRM_FH_SURFACE_WATER_VELOCITY_H)

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.本次公开的地表洪水（surface water flooding）概率等级如下： - 高概率：10年一遇重现期（return period） - 中概率：200年一遇重现期 - 低概率：基于2080年代英国2009年气候预测（UKCP09）高排放情景，叠加气候变化影响的200年一遇重现期洪水 地表洪水灾害图（surface water hazard maps）将展示（如可获取）以下内容： - 洪水淹没范围 - 洪水水深 - 酌情展示洪水流速（Flood velocities）。流速是否予以展示，需综合考量输入数据可信度、建模方法与影响后确定，当前流速被划分为四个等级之一。 本数据集所采用的气候变化情景，基于英国2009年气候预测（UKCP09）针对2080年高排放情景的95%分位数（95%ile）预测结果。中、低概率洪水事件的选取标准，与苏格兰规划政策中采用的重现期保持一致；而高概率洪水事件的选取，则贴合近数十年来实际观测到的洪水事件特征。