ni, guangheng （倪广恒） department of hydraulic engineering, tsinghua university, china

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

∗ 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

Contents

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

∗ 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

——Basic Statistic

∗ 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

∗ Based on runoff data from 22 hydrological stations∗

Total ： 1.772 billion m3∗ Mountain ： 1.159

billion m3∗ Plain ： 0.613 billion

m3∗ 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 ——Surface Water

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——Groundwater

Resources

0

200

400

600

100040

800

1200

1400

1600

1800

0

10

20

30

50

60

70

80

1985 1990 1995 2000 2005 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

Evaluation of Water Resources in Beijing ——Ground Water

Elevations

∗ 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

Total Water Resources in Beijing

17.72

25.59

37.39

∗ Beijing and Water

∗ Urban Floods in Beijing

∗ Management of Urban Floods

∗ Flood Resilience Beijing

Contents

∗ 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

Flood in July 2004, Beijing

Flood in July 2012, Beijing

Flood in July 2012, Beijing

∗ Flood peak at Juma River of Fangshan = 2570 m3/sec∗ Inundated sites = 63, maximum depth = 6m∗ Houses, roads, bridges, hydraulic structures

Damage of the 7.21 Flood

∗ 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

Heavy Rainfall

Impact of Climate Change?

1985 2005

Impact of Urbanization?

Urbanization: Increased Ratio of Impervious Area

GDP

Population

Pop

ulat

ion

(104 )

GD

P (1

08 RM

B)

Urbanization: Social & EconomicalDevelopme

nt

∗ 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

Inadequate Urban Flood Management

Sewer

Xinxing Brg

Lianhua Brg

Inundation at Flyovers

Channel 莲花池

Inundation at Flyovers

Sewer

Xinxing Brg

Lianhua Brg

莲花池Channel

Inundation

Inundation Locations

∗ Beijing and Water

∗ Urban Floods in Beijing

∗ Management of Urban Floods

∗ Flood Resilience Beijing

Contents

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 )

∗ Pervious pavement∗ Lower grass land∗ Green roof∗ Infiltration trench∗ Retarding storage

On-site Infiltration/Storage Facility

On-site Facilities

Green Roof Effect in Runoff Reduction

∗ 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

∗ Beijing and Water

∗ Urban Floods in Beijing

∗ Management of Urban Floods

∗ Flood Resilience Beijing

Contents

Master Plan of Flood Management

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 Structure & Equations

Model Application in Beijing

Model Application in Beijing

Model Application in Beijing

Impact of Urbanization on Rainfall

UCM (Urban Canopy Model)

TR2 TR1

zT

soil heat storage

rw

TW2

TG1 TG2 TG3

TW1

Tcanh

GR,i

GW,i

Ti

Wang, Z., Bou-Zeid, E., & Smith, J. A. (2011), Sun et al (2012).

Asphalt GrassConcrete

PROM

Ta

Ta

Ta

HR Hcan

z R

z a

z

Green Roof Ordinary Roof

Princeton ROofMod

el

High Resolution Rainfall Estimation and Forecasting

Towards Smart System of Urban Flood Management

High Resolution Rainfall Estimation and Forecasting

Thanks for your kind attention!