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.本次提供的地表积水洪涝（surface water flooding）概率分级如下： - 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，叠加气候变化影响的200年一遇重现期 地表积水洪涝风险地图（如可获取）将展示以下内容： - 淹没范围 - 淹没水深 - 适宜场景下的洪水流速。洪水流速的展示需满足判定条件：将综合考量输入数据可信度、建模方法及影响程度进行判定，当前流速分为四个等级进行展示。 本数据集所采用的气候变化情景，基于英国气候预测2009（UKCP09）针对2080年高排放情景下95%分位数的预测结果设定。本次选取中、低概率洪涝事件，是为与《苏格兰规划政策》中采用的重现期标准保持一致；而高概率洪涝事件的选取，则基于近数十年间已观测到的实际洪涝事件特征。