1. Ni, Guangheng （倪广恒） Department of Hydraulic Engineering, Tsinghua University, China The Management of Beijing Urban Floods 北京都市水患研究與防治對策 2013 大高雄治水論壇

2. ∗ Water Resources in Beijing ∗ Urban Floodsin Beijing ∗ Management of Urban Floods ∗ Flood Resilience in Beijing Contents

3. ∗ Water Resources in Beijing ∗ Urban Floodsin Beijing ∗ Management of Urban Floods ∗ Flood Resilience Beijing Contents

4. Taking the contour of 100m as the borderline separating into mountain and plain. Total number of calculation elements: 31

5. 北京市水系圖 Water system map in Beijing

6. ∗ Total area ： 16,800km 2 ∗ North Haihe River catchment ： 1,4581km 2 ∗ South Haihe River catchment ： 2,219km 2 ∗ 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 ——Basic Statistic

7. ∗ 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 ——Precipitation, Evapotranspiration, Sediment

8. ∗ Based on runoff data from 22 hydrological stations ∗ Total ： 1.772 billion m 3 ∗ Mountain ： 1.159 billion m 3 ∗ Plain ： 0.613 billion m 3 ∗ Inflow ： 1.606 billion m 3 （ 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 m 3 (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 ——Surface Water Resources

9. ∗ Divided into plain, intermountain basin and mountain ∗ Using 11 water balance calculation regions ∗ Plain ： 2.289 billion m 3 ∗ Mountain (Effective infiltration from precipitation ) ： 1.095 billion m 3 ∗ Repeated (double calculated) ： 0.825 billion m 3 ∗ 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 m 3 Evaluation of Water Resources in Beijing ——Groundwater Resources

10. 0 200 400 600 1000 40 800 1200 1400 1600 1800 0 1010 2020 3030 5050 6060 7070 8080 1985 1990199520002005 2010 人口 ( 万人 ) 用水量 ( 亿 m 3 ) 总用水量 农业用水工业用水生活用水人口 Evaluation of Water Resources in Beijing ——Long Term Water Consumption Pattern 年份

11. Evaluation of Water Resources in Beijing ——Ground Water Elevations

12. ∗ Surface water resources ： 1.772 billion m 3 ∗ Groundwater resources ： 2.559 billion m 3 ∗ Total water resources ： 3.739 billion m 3 ∗ Repeated part ： 0.592 billion m 3 Wrs per capita: 6833m 3 /person 205m 3 /person Total Water Resources in Beijing 17.72 25.59 37.39

13. ∗ Beijing and Water ∗ Urban Floodsin Beijing ∗ Management of Urban Floods ∗ Flood Resilience Beijing Contents

14. ∗ 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 Urban Floods in Beijing

15. Floodin July 2004, Beijing

16. Floodin July 2012, Beijing

18. ∗ Flood peak at Juma River of Fangshan = 2570 m 3 /sec ∗ Inundated sites = 63, maximum depth = 6m ∗ Houses, roads, bridges, hydraulic structures Damage of the 7.21 Flood

19. ∗ Long duration ∗ 9:00 July 21 st – 4:00 July 22 nd ∗ Heavy intensity ∗ Maximum 541 mm (RP = 500yrs) ∗ Maximum in urban area 328 mm (RP = 100yrs) ∗ Over whole Beijing 170mm ∗ Over central urban area 215mm Heavy Rainfall

20. Impact of Climate Change?

21. 19852005 Impact of Urbanization?

22. Urbanization: Increased Ratio of Impervious Area

23. GDP Population Popu l a t i on ( 10 4 ) G D P ( 10 8 R M B) Urbanization: Social & Economical Development

24. ∗ 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

26. Sewer Xinxing Brg Lianhua Brg Inundation at Flyovers Channel 莲花池

27. Inundation at Flyovers Sewer Xinxing Brg Lianhua Brg 莲花池 Channel Inundation

28. Inundation Locations

30. ∗ Beijing and Water ∗ Urban Floodsin Beijing ∗ Management of Urban Floods ∗ Flood Resilience Beijing Contents

31. Small Watershed Management 封 ( 封禁治理 ) 移 ( 生态移民 ) 补 ( 生态补偿 ) 第一道防线 调 ( 结构调整 ) 沟道治理 护村坝 农村环境整治 农户改厕 垃圾处置 第二道防线 清 ( 清理河道 ) 污水处理 农路 工程 护地坝 第三道防线 节 ( 节水灌溉 ) 育 ( 保育植被 ) 树盘工程 保 ( 恢复河道景观 ) 节 ( 节水灌溉 ) 补 ( 生态补偿 ) 移 ( 生态移民 ) 封 ( 封禁治理 ) 农户改厕 污水处理 垃圾处置 农路工程 农村环境整治 沟道治理 调 ( 结构调整 ) 护村坝 梯田整修 护地坝 树盘工程 清 ( 清理河道 ) 育 ( 保育植被 ) 保 ( 恢复河道景观 ) 第三道防线 第一道防线 第二道防线 绿化 治 ( 河岸带治理 )

32. ∗ Pervious pavement ∗ Lower grass land ∗ Green roof ∗ Infiltration trench ∗ Retarding storage On-site Infiltration/Storage Facility

33. On-site Facilities

34. Green Roof Effect inRunoff Reduction

35. ∗ 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 Forecasting and Warning System 出现降雨 实时雨情 天气预报 Ⅳ - 一般 - 蓝 Ⅲ - 较大 - 黄 Ⅱ - 重大 - 橙 Ⅰ - 特别重大 - 红 洪涝灾害 防汛突发事件

36. ∗ Beijing and Water ∗ Urban Floodsin Beijing ∗ Management of Urban Floods ∗ Flood Resilience Beijing Contents

37. Master Plan of Flood Management

38. 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

39. 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 Structure & Equations

40. Model Application in Beijing

43. Impact of Urbanization on Rainfall

44. UCM (Urban Canopy Model) TR2TR1TR2TR1 zTzT soil heat storage r w TW2TW2 TG1TG2TG3TG1TG2TG3 TW1TW1 T can h G R,i G W,i TiTi Wang, Z., Bou-Zeid, E., & Smith, J. A. (2011), Sun et al (2012). AsphaltGrass Concrete PROMTaTaPROMTaTa TaTa HRHR H can z R z a z Green Roof Ordinary Roof Princeton ROof Model

45. High Resolution Rainfall Estimation and Forecasting

46. Towards Smart System of Urban Flood Management High Resolution Rainfall Estimation and Forecasting

47. Thanks for your kind attention!