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.本次地表积水洪涝（surface water flooding）数据集包含以下概率等级情景： - 高概率：10年一遇重现期 - 中概率：200年一遇重现期 - 低概率：采用2080年代英国气候预估2009（UKCP09）高排放情景叠加气候变化影响的200年一遇重现期情景 地表积水洪涝风险图（若可获取）将展示以下内容： - 淹没范围 - 淹没水深 - 适宜场景下的淹没流速。流速是否予以展示，需结合输入数据可信度、建模方法及影响评估综合判定，当前流速共分为四个等级进行呈现。 本数据集采用的气候变化情景，基于英国气候预估2009（UKCP09）针对2080年高排放情景的95%分位数预测结果定义。 本次选取中、低概率洪涝情景，旨在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为贴合近数十年来实际观测到的洪涝事件特征。