River Flood Maps (FRM_FH_RIVER_VELOCITY_M)

These maps have been produced to meet SEPA’s duty to publish flood hazard maps as set out in the Flood Risk Management (Scotland) Act 2009. The maps show where there is a risk of flooding from the sea, from rivers and from surface water.The following probabilities are available for river flooding: - High - 10 year return period - Medium - 200 year return period - Low - 1000 year return period and 200 year return period plus climate change using the UKCP09 high emissions scenario for the 2080s.The river 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. 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 bandsMedium 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.本批洪水危险性地图（flood hazard maps）系为履行苏格兰环境保护署（Scottish Environment Protection Agency, SEPA）的法定职责编制，符合《洪水风险管理（苏格兰）法案2009》（Flood Risk Management (Scotland) Act 2009）中关于发布洪水危险性地图的要求。本地图展示了海洋、河流及地表径流引发的洪水风险分布区域。 针对河流洪水，本次数据集提供以下不同概率等级的图层： - 高概率：10年一遇重现期（return period） - 中概率：200年一遇重现期（return period） - 低概率：1000年一遇重现期（return period），以及叠加2080年代英国气候预估2009（UK Climate Projections 2009, UKCP09）高排放情景气候变化影响的200年一遇重现期场景 河流洪水危险性地图将在数据可用时展示以下内容： - 洪水淹没范围（flood extent） - 洪水水深（flood depth） - 适宜场景下的洪水流速（flood velocities） 本次采用的气候变化情景基于英国气候预估2009（UKCP09）针对2080年高排放场景的95%分位数（95%ile）预测结果。洪水流速图层仅在适宜场景下提供，其生成需综合考量输入数据可靠性、建模方法及影响效果，当前分为四个等级进行展示。 本次选取中、低概率洪水场景，以匹配《苏格兰规划政策》中采用的重现期标准；而高概率场景的选取则基于近数十年间实际观测到的洪水事件特征。