The Management of Beijing Urban Floods
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2013 大高雄治水論壇 The Management of Beijing Urban Floods 北京都市水患研究與防治對策 Ni, Guangheng （倪广恒） Department of Hydraulic Engineering, Tsinghua University, China Contents ∗Water Resources in Beijing ∗Urban Floods in Beijing ∗Management of Urban Floods ∗Flood Resilience in Beijing Contents ∗Water Resources in Beijing ∗Urban Floods in Beijing ∗Management of Urban Floods ∗Flood Resilience Beijing Taking the contour of 100m as the borderline separating into mountain and plain. Total number of calculation elements: 31 北京市水系圖 Water system map in Beijing Evaluation of Water Resources in Beijing ——Basic Statistic ∗ Total area：16,800km2 ∗ North Haihe River catchment：1,4581km2 ∗ South Haihe River catchment：2,219km2 ∗ District/ County: 18 ∗ Urban area：4 ∗ Suburb： 14 ∗ Water Resources third-class region: 2 ∗ North Haihe River Tributaries: 3 ∗ Beisi River Lower Reaches ∗ Beisan River Mountain Basin ∗ Region from Cetian Reservoir to Sanjiadian in Yongding River Basion ∗ South Haihe River Tributaries：2 ∗ Daqing River Dianxi Plain ∗ Daqing River Mountain Basin Evaluation of Water Resources in Beijing ——Precipitation, Evapotranspiration, Sediment ∗ Mean annual precipitation （year 1956 ~ year 2000）: ∗ 584.7mm（10 sites） ∗ Mountain： 576.9mm; Plain： 597.2mm; ∗ Trend: decreasing ∗ Aridity Index: 1.2~2.5 ∗ Significantly decreased trend in sediment yield ∗ Since 1980, Precipitation decreased and flood rarely took place ∗ The effect of Water conservancy projects on sediment detention ∗ The effect of Water and Soil Conservation Evaluation of Water Resources in Beijing ——Surface Water Resources ∗ Based on runoff data from 22 hydrological stations ∗ Total： 1.772 billion m3 ∗ Mountain：1.159 billion ∗ 0.613 billion m3 m3Plain： ∗ Inflow：1.606 billion m3（decreased trend） ∗ Yongding River, Chaobai River, Jiyun River ∗ Juma River is in the boundary, so inflow of the river is considered as passing water ∗ Outflow: 1.415 billion m3 (clean water and wastewater) ∗ Beiyong River,Yongding River, Chaobai River, Jiyun River ∗ Outflow of Juma River is considered as passing water Evaluation of Water Resources in Beijing ——Groundwater Resources ∗ ∗ ∗ ∗ ∗ Divided into plain, intermountain basin and mountain Using 11 water balance calculation regions Plain：2.289 billion m3 Mountain (Effective infiltration from precipitation )：1.095 billion m3 Repeated (double calculated)： 0.825 billion m3 ∗ Infiltration replenishment of the mountain side ∗ Infiltration replenishment of surface water based on base-flow in plain area ∗ Total groundwater resources： 2.289+1.095-0.825=2.559 billion m3 Evaluation of Water Resources in Beijing ——Long Term Water Consumption Pattern 总用水量 农业用水 工业用水 生活用水 人口 1600 70 1400 60 1200 50 用水量(亿m3 ) 1800 1000 40 800 30 600 20 400 10 200 0 1985 1990 1995 2000 年份 2005 0 2010 人口(万人) 80 Evaluation of Water Resources in Beijing ——Ground Water Elevations Total Water Resources in Beijing ∗ Surface water resources： 1.772 billion m3 ∗ Groundwater resources： 2.559 billion m3 ∗ Total water resources： 3.739 billion m3 ∗ Repeated part： 0.592 billion m3 Wrs per capita: 6833m3/person 205m3/person 17.72 37.39 25.59 Contents ∗Beijing and Water ∗Urban Floods in Beijing ∗Management of Urban Floods ∗Flood Resilience Beijing Urban Floods in Beijing ∗ 清代北京水灾记载较详细，堪称“特大”的有5次。 ∗ 分别是顺治十年（1653年），康熙七年（1668年）， 嘉庆六 年（1801年），光绪十六年（1890年）和十九年 （1893年）。 ∗ ∗ ∗ ∗ ∗ August, 1959 August, 1963 July, 2004 June, 2011 July, 2012 ∗ ∗ Direct economic loss: 11.64 billion RMB 79 death Flood in July 2004, Beijing Flood in July 2012, Beijing Flood in July 2012, Beijing Damage of the 7.21 Flood ∗Flood peak at Juma River of Fangshan = 2570 m3/sec ∗Inundated sites = 63, maximum depth = 6m ∗Houses, roads, bridges, hydraulic structures Heavy Rainfall ∗ Long duration ∗ 9:00 July 21st – 4:00 July 22nd ∗ Heavy intensity ∗ Maximum 541 mm (RP = 500yrs) ∗ Maximum in urban area 328 mm (RP = 100yrs) ∗ Over whole Beijing 170mm ∗ Over central urban area 215mm Impact of Climate Change? Impact of Urbanization? 1985 2005 Urbanization: Increased Ratio of Impervious Area Urbanization: Social & Economical Development Population (104) Population GDP (108RMB) GDP Inadequate Urban Flood Management ∗ Lower standard of sewerage system ∗Most parts, 1-3yrs return period, 36-45mm/hr ∗Limited areas, 5yrs return period, 56mm/hr ∗New York 10-15yrs; Tokyo 5-10yrs ∗ Separated regulation of rivers, lakes and drainage Inadequate Urban Flood Management Inundation at Flyovers Xinxing Brg Sewer Lianhua Brg Channel 莲花池 Inundation at Flyovers Xinxing Brg Sewer Lianhua Brg Inundation Channel 莲花池 Inundation Locations Contents ∗Beijing and Water ∗Urban Floods in Beijing ∗Management of Urban Floods ∗Flood Resilience Beijing Small Watershed Management 封(封禁治理) 第一道防线 第一道防线 调(结构调整) 调(结构调整) 护村坝 护村坝 农户改厕 沟道治理 绿化 移(生态移民) 沟道治理 农村环境整治 农户改厕 补(生态补偿) 农村环境整治 垃圾处置 垃圾处置 第二道防线 第二道防线 梯田整修 清(清理河道) 清(清理河道) 污水处理 污水处理 农路工程 护地坝 工程 护地坝 第三道防线 第三道防线 节(节水灌溉) 节(节水灌溉) 育(保育植被) 育(保育植被) 树盘工程 树盘工程 治(河岸带治理) 保(恢复河道景观) 保(恢复河道景观) 农路 On-site Infiltration/Storage Facility ∗Pervious pavement ∗Lower grass land ∗Green roof ∗Infiltration trench ∗Retarding storage On-site Facilities Green Roof Effect in Runoff Reduction Forecasting and Warning System 天气预报 ∗ 国家防汛抗旱指挥部 ∗ 北京市防汛抗旱指挥部办公 室 ∗ 北京市水务局 ∗ 北京市气象局 ∗ 北京市交通局 洪涝灾害 防汛突发事件 Ⅳ-一般-蓝 Ⅲ-较大-黄 Ⅱ-重大-橙 Ⅰ-特别重大-红 出现降雨 实时雨情 Contents ∗Beijing and Water ∗Urban Floods in Beijing ∗Management of Urban Floods ∗Flood Resilience Beijing Master Plan of Flood Management Model Structure & Equations The top layer is two-dimensional grid network representing various urban landscapes (runoff generation areas); The middle and bottom layers are one-dimensional street network and sewer network, respectively; The side layer is one- dimensional ditch/river network. THUmodel ( TsingHua Urban model) Model Structure & Equations Richards equation: Diffusive wave model of 2D Saint-Venant equation: Dynamic wave model of 1D Saint-Venant equation: Weir, sluiced gate equation for exchange flux between street and sewer nodes: Model Application in Beijing Model Application in Beijing Model Application in Beijing Impact of Urbanization on Rainfall UCM (Urban Canopy Model) z za Princeton ROof Model PROM Ta Ta Ta HR Green Roof zR TR2 Hcan Ordinary Roof TR1 TW1 GR,i Tcan zT GW,i Ti TW2 soil heat storage Asphalt TG1 TG2 Concrete w TG3 Grass r Wang, Z., Bou-Zeid, E., & Smith, J. A. (2011), Sun et al (2012). h High Resolution Rainfall Estimation and Forecasting Towards Smart System of Urban Flood Management High Resolution Rainfall Estimation and Forecasting Thanks for your kind attention!
