Surface Water Flood Maps (FRM_FH_SURFACE_WATER_EXTENT_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. The 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.

本次可获取的地表洪水概率分级及对应情景如下：
- 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年一遇情景。

地表洪水危险性地图可提供以下内容（视情况提供）：
- 洪水淹没范围
- 洪水水深
- 适宜场景下的洪水流速。

本数据集所用的气候变化情景，依据英国气候预测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、低概率洪水事件，以匹配苏格兰规划政策中采用的重现期标准；而高概率洪水事件的选取，则反映了近数十年来实际观测到的洪水事件特征。