Surface Water Flood Maps (FRM_FH_SURFACE_WATER_VELOCITY_M)

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.下述为地表积水洪涝（surface water flooding）灾害的各类概率场景： - 高概率：10年一遇重现期 - 中概率：200年一遇重现期 - 低概率：2080年代采用英国气候预测2009（UKCP09）高排放情景的200年一遇重现期叠加气候变化影响 地表积水灾害风险图涵盖以下内容（如可获取）： - 洪涝淹没范围 - 洪涝水深 - 适宜评估场景下的洪涝流速。流速仅在符合评估要求的场景下展示，其判定需结合输入数据可信度、建模方法与影响评估结果，当前将流速划分为4个等级区间。 本研究采用的气候变化情景，基于英国气候预测2009（UKCP09）针对2080年代高排放情景的95%分位数预测结果设定。中、低概率洪涝场景的选取参考了苏格兰规划政策中的重现期标准，而高概率场景则选取与近数十年实际观测到的洪涝事件特征相符的等级。