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.本次公开的地表洪水概率分级如下： - 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）高排放情景下的气候变化影响修正后的200年一遇重现期 地表洪水危险性地图将展示（如可获取相关数据）以下内容： - 洪水淹没范围 - 洪水水深 - 适用场景下的洪水流速 流速的展示需视实际情况而定，其展示与否需综合考量输入数据可信度、建模方法与影响评估结果，当前流速被划分为四个等级之一进行呈现。 本数据集采用的气候变化情景基于英国气候预测2009（UKCP09）针对2080年高排放情景的95%分位数预测结果。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规范保持一致，而高概率洪水事件的选取则反映了近数十年间实际观测到的典型洪水事件特征。