1、Green roofsRain gardensSwalesPermeable pavement绿色屋顶雨水花园植草沟渗透铺装Can the combined effect of many small facilities capturing small runoff volumes reduce flood risk?将很多降低小雨径流量的小型设施结合起来能够减少雨洪风险吗？将很多降低小雨径流量的小型设施结合起来能够减少雨洪风险吗？Background 背景介绍Methodology overview 方法概述Results 结果Conclusions 结论Objective:Estimate
2、 flood damages avoided by nationwide implementation of GI for new development and redevelopment目的：针对新开发和再开发的土地广泛地应用绿色基础设施来控制雨洪并估计因此而避免的雨洪损失Rationale:Smaller runoff volume leads to smaller floodplains and thus fewer flood damages合理性：径流量越小，洪泛区越小，所以雨洪损失越小Capture and retain on site a large number of sto
3、rms捕获并原位滞留大量的暴雨Xth percentile storm:The event whose precipitation depth is greater than or equal to X%of all storm events over a given period of record第X百分位的暴雨是指：在给定的记录期间，降雨深度大于等于所有降雨事件的X%的降雨事件The retained volume must be infiltrated,evapotranspired,or harvested for beneficial use滞留的径流必须通过渗透，蒸腾或者回用来处
4、理掉Evaluate 20 watersheds with and without GI对20个汇水区在增设绿色基础设施前后的情况进行评估Estimate monetary flood damages for each scenario估测每种情形下的雨洪损失（以货币形式计）Benefits=flood damages without GI flood damages with GI收益=没有绿色基础设施时的雨洪损失-有绿色基础设施时的雨洪损失Scale results nationwide衡量全国范围的结果BackgroundMethodology overviewResultsConclu
5、sionsSample of 20 large watersheds(1500 to 8000 km2)20个大汇水区的样本（1500到8000平方公里）Publicly available datasets公共可用的数据集Peak flows from stream gage records水标尺记录的峰流Water surface elevations from hydraulic modeling来自水利模型的水面标高Monetary damage estimation using the Hazus model用Hazus模型估算的货币形式的损失Regression analysis
6、to extrapolate to other watersheds用回归分析外推其他汇水区的情况Streamflow records from the US Geological Survey(USGS)河川流量记录来自美国地质勘探局USGS National Elevation Dataset(NED)(10-meter digital elevation model,DEM)美国地质勘探局国家高程数据集（NED）（10m的数字高程模型，DEM）Stream topology from the National Hydrography Dataset by the USGS河流地质特征来自
7、国家水文数据集National Land Cover Dataset(NLCD)developed by a consortium of 10 US Federal agencies10个美国联邦机构联合开发的国家土地覆盖数据集STATSGO2 soils by the US Natural Resources Conservation Service美国自然资源保护服务机构的STATSGO2土壤数据Economic activity from the US Census Bureau美国人口统计局的经济活动Economic growth projections from the Integr
8、ated Climate and Land Use Scenarios(ICLUS)model,developed by the US Environmental Protection Agency来自综合气候和陆地使用情况模型的经济增长预测，该模型由美国环保署开发1.Hydraulic modeling to estimate flood depths with and without GI用水利模型来估计增设绿色基础设施前后的洪流深度2.Estimate monetary damages with and without GI估计两种情况下的经济损失3.Damages avoided=Da
9、mages without GI Damages with GI可避免的损失=不设绿色基础设施的损失-设置绿色基础设施之后的损失Atkins Rapid Flood Delineation(RFD)modelAtkins的快速洪流划分（RFD）模型High speed hydraulic profile calculation(6,000 miles per CPU hour)高速水利剖面计算（每个CPU小时可以计算6000英里）Depth grids深度网格模型Physical Damage物理损失Economic Loss经济损失Social Impacts社会影响Shelter requ
10、irements需要避难所Displaced households很多家庭流离失所Population exposed to scenario floods,earthquakes,and hurricanes遭遇洪水，地震和飓风的人口数量 US Federal Emergency Management Agency(FEMA)model for estimating potential losses from disasters美国联邦紧急事务管理署模型用来估计灾害所带来的潜在损失 GIS-based基于GIS的方法-10-50510152025300%20%40%60%Flooding d
11、epth(ft)Percent Structural DamageVulnerability CurveOne-story house,no basementBackgroundMethodology overviewResultsConclusionsMiddle James,without GIUpper San Antonio,without GIAverage Annualized Losses(AAL)=area under damage curve年平均损失（AAL）=损失曲线以下的面积Middle James,without GIUpper San Antonio,without
12、 GIDamages avoided100-year eventno GI不设置绿色基不设置绿色基础设施情况下，础设施情况下，100年一遇的年一遇的降雨事件降雨事件100-year eventwith GI设置绿色基础设置绿色基础设施情况下，设施情况下，100年一遇的年一遇的降雨事件降雨事件2-year eventno GI不设置绿色基不设置绿色基础设施情况下，础设施情况下，2年一遇的降雨年一遇的降雨事件事件2-year eventwith GI设置绿色基础设置绿色基础设施情况下，设施情况下，2年一遇的降年一遇的降雨事件雨事件Year 2040 development(2011 dollars
13、)Optimistic Year 2040 development(2011 dollars)Neutral Year 2040 development(2011 dollars)Conservative Regression of damages avoided vs.watershed properties将可避免的损失和汇水区特征进行回归分析Value of assets exposed to floods遭受洪水灾害的资产价值Climate气候Future urban development forecast未来城市发展预测Avoided losses in 2040=$730 mil
14、lionPresent value(2020-2040)=$5 billionAvoided losses in 2040=$330 millionPresent value(2020-2040)=$2.3 billionAvoided losses in 2040=$110 millionPresent value(2020-2040)=$0.8 billionWhen applied watershed wide,GI contributes to flood resilience by reducing在汇水区规模上，绿色基础设施有助于洪水恢复，主要是减少了以下一些参数Peak flow
15、s for flood events洪流事件的峰流量Flood elevations洪水高程Flood damages洪水损失A relatively small volume of runoff captured can noticeably reduce damages for all flood events绿色基础设施捕获的径流量相对少但是能够显著减少所有洪水事件带来的损失GI is necessary for water quality and stream health设置绿色基础设施对于水质和河川的健康很有必要GI adds community resiliency and environmental protection绿色基础设施增加了社区的恢复力以及环境的保护力GI reduces future government expenditures and protects existing investments in flood control绿色基础设施减少了政府将来的支出并且保护了在洪水控制方面现有的投资Need to improve messaging about the link between runoff volume reduction and flood damage avoidance有关减少径流量和避免洪水损失之间链接的信息有待提高
