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：对应10年一遇重现期 - 中概率：对应200年一遇重现期 - 低概率：对应叠加气候变化影响的200年一遇情景，采用英国气候预估2009（UKCP09）的2080年代高排放场景 地表洪水危险性制图（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 - 适宜场景下的洪水流速 流速的展示需满足特定条件：其判定依据为输入数据、建模方法与影响评估的置信度水平，当前将流速划分为四个等级区间。 本次所用的气候变化情景，基于英国气候预估2009（UKCP09）针对2080年高排放场景的95%分位数预测结果设定。中、低概率洪水情景的选取，与苏格兰规划政策中采用的重现期标准保持一致；而高概率情景的选取，则反映了过去数十年间已观测到的洪水事件特征。