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.本次提供的地表洪水（surface water flooding）灾害概率等级如下： - 高概率：10年一遇重现期（return period） - 中概率：200年一遇重现期 - 低概率：采用英国2009年气候投影（United Kingdom Climate Projection 2009，UKCP09）2080年代高排放情景下的气候变化影响，叠加200年一遇重现期的洪水事件 地表洪水灾害风险图（若可获取）将展示以下内容：洪水淹没范围、洪水水深，以及适宜场景下的洪水流速。流速的展示与否需视情况而定：其展示标准由输入数据可信度、建模方法与影响评估共同决定，当前流速被划分为四个等级区间进行展示。 本数据集采用的气候变化情景，基于UKCP09针对2080年高排放情景下的95%分位数预测结果确定。本次选取中、低概率洪水事件，是为了与苏格兰规划政策中采用的重现期标准保持一致；而高概率洪水事件的选取，则因其能够反映近数十年来实际观测到的洪水事件特征。