台灣下水道協會首頁 - 슬라이드 1 SESSION/2.pdfInvestment for Storm water pipelines are significantly lower compared to that for sanitary drain pipelines (Last 5year 6.2

July 2013

2 Status of Sewerage

3 Sewerage Policy against Urban Flooding

4 Implementation Status of Sewerage Maintenance Projects to cope with Flooding

5 Anticipated Effect

1 Change of rainfall pattern according to Climate change

2/28


<Annual ave. Precipitation> <Dry season> <Rainy season>

Anticipated 22% increase in precipitation in 2100 vs 2010

<Trend of past precipitation >

Rainy season-increase in precipitation, Dry season- decrease in precipitation

Deepening of seasonal deviation of precipitation & continuous increase in precipitation

Anticipated continuous increase in precipitation in the future

increase in surface effluent during flood season

• increase in surface effluent flow during flood season

※ Seoul : 502 thousand ㎥/day in 1960’s → 2,990 thousand ㎥/day in 2000’s

Approx. 500% Increase

Due to increase in impermeable area, surface effluent in Urban area is not infiltrated and is intensively flow to Downstream In short period of time

Approx. 603% increase

• Increase in impermeable area

rate

※ Seoul: 7.8% in 1960’s → Over 47% in 2000’s

Impermeable area rate

Land impermeable area rate

Road impermeable area rate

Imperm

eable

are

a

rate

Year

Surf

ace e

fflu

ent

flow

in f

lood

season(0

00m

3/d

ay)

Daily average of surface effluent flow in flood season – Increase by 2,488 thousand m3

Month

ly a

vera

ge p

recip

itation(m

m) Target:

Nationwide

3/28


Case of urban flooding according to climate change

Localized heavy Rainfall which is exceed existing frequency of rainfall has been occurred frequently by Weather Anomaly

<Occurrence trend of rainfall over max 50mm/hr and 300mm/day)

구 분 ‘50~’60 ‘60~’70 ‘70~’80 ‘80~’90 ‘90~’00 ‘00~’08

Number of Occurrence Over max 50mm/hr

8 11 32 66 86 111

Number of Occurrence Over max 300mm/day

0 1 7 14 20 18

4/28

Heavy rainfall in metropolitan area (September 2010)

-Amount of Heavy rainfall is 259.5 ㎜ in 21. Sep. (from pm 1 to pm 4:20) : exceed frequency of rainfall 100 years

Unprecedented localized heavy rainfall after finishing rainy season during the short term at the middle area (July 26~28. 2011) ※ the amount of precipitation (588mm) during 3 days(7.26~28) in Seoul is the highest record since weather observation carried (From 1907)

Annual amount of rainfall is increased, but the number of occurrence and average duration time of rainfall is decreased ⇒ Localized heavy rainfall is increased

Occurrence frequency of localized heavy rainfall(over 80mm per a hour) is increased 1.7times from 22 days in 1970’s to 37 days in 2000’s

History of Sewerage Policy

※ Afterwards – General measure for clear water supply in 1993, General measure for water management in 1996 and General measure for 4 major rivers water management in 1999

※ Feasibility study on nationwide sewer maintenance during 2002-2004 [1 sewer spot per every 8.6m showed defects)

1966 Enacted the Sewerage Act (The 1st construction of Cheonggyecheon Wastewater Treatment Plant in 1976 with daily capacity of 150 thousand tons)

1989 Established general measure for the supply of clear water (Jointly by ministries concerned with supervision by Prime Minister’s Office)

1994 Transferred sewerage works from Ministry of Land, Infrastructure and Transport to Ministry of Environment

2002 Proclaimed ‘the 1st year for Sewer pipeline maintenance’, Start to implement sewer maintenance projects

2005 Commenced BTL (Build-Transfer-Lease) project for sewer pipeline maintenance, Implemented expansion of upstream sewerage for multi-purpose dam

2007 Entirely amended Sewerage Act (Consolidated the Wastewater and Excreta Act and the Sewerage Act. Implemented on Sept. 28, 2007)

2010 Implemented a four-river refurbishment project , T-P treatment facility installation, rainwater detention storage facility installation

2012 Implemented integrated management of sewerage facilities, urban flooding prevention measure, water reuse


5/28

Sewerage supply service rate


Sewer pipeline distribution rate

8.5%(’86) ⇒ 37.0%(’87) ⇒ 52.6%(’96) ⇒ 85.5%(’06) ⇒ 90.9%(’11)

48.3%(’86) ⇒ 49.5%(’87) ⇒ 62.6%(’96) ⇒ 71.2%(’06) ⇒ 73.4%(’11)


0

20

40

60

80

100

0

5,000

10,000

15,000

20,000

25,000

30,000

'86 '87 96 '06 11

(%)(천톤/일) 하수도 보급률

시설용량(천톤/일)보급률(%)


Facility capacity (ton/day)

supply rate

(ton/day)

0

20

40

60

80

100

0

30,000

60,000

90,000

120,000

150,000

180,000

'86 '87 '96 '06 '11

(%)(연장:Km) 하수관거 보급률

계획연장(km)시설연장(km)보급률(%)

Sewer pipelines Supply rate

Planned total length (km)

Facility total length (km)

(total length: Km)

supply rate

6/28


Status of rainfall management

Rainfall storage and infiltration facility is called different name according to purpose, type and related Act, but the facilities have a similliar function

organization Rainfall management

facility Object Act and Regulaltion

Ministry of Environment

Sewer pipeline Wastewater detention Storage facility

Prevention of flooding and improvement of water quality by drainage & storage of rainfall

Sewerage Act, Sewerage facility standard

Non-point source reduction facility

Improvement of water quality by rainfall infiltration and storage

Water Quality and Ecosystem Conservation Act

Rainfall use facility Storage of rainfall using for residential water Promotion of and support for water reuse Act

Buffer storage facility Prevent water pollution accident in industry complex caused by rainfall and wastewater outflow using temporary storage

Nakdong-river water basin special Act

National Emergency Management

Agency

Rainfall outflow reduction facility

Prevention of disaster by rainfall infiltration and storage

Prevention of natural disaster Act

Ministry of Land, Infrastructure and Transport

Drainage way, rainfall pump station, retarding basin, storage basin

Prevention of Flooding River Act, River plan standard

7/28

1. Background & Problems Water control ability is weaken due to

deteriorated Storm water Conduit function Major cause for flooding – Internal water flooding

Rapid increase of damage from flooding

(백억원)

Increase more

than 226%

Bigger damage from internal water flooding (73%) due

To insufficient sewer pipeline capacity than damage

from overflow of external water (27%)

Flooding area was reduced, damage amounts shows rapidly increasing trend (620 bil. won in 1990’s ➡ 2,100 bil. Won in 2000’s (226%)

< Distribution by flooding

cause >

< Flooding area & Damage amount Trend >

(Internal/external water

flooding ratio)

Storm water conduits are deteriorated

Pipelines defects


Elapsed year Total length of pipelines (km)

Over 30 years

Less than 20-30 years


Less than 15 years

Over 30 years

Less than 15 years



External

Internal

Lowland

Others Storm water

exclusion system problem

Lack of capacity for pipeline (11%)

Insufficient drainage capacity

(14%)

River level surge (14%)

Street drainage (13%)

Insufficient cross section of drain (7%)

Insufficient drainage facility (6%)

(Internal water flooding classification)

62

210

0

50,000

100,000

150,000

200,000

250,000

-

100

200

300

400

500

600

700

800

900

1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009

피해액

(백억원

)

침수피해액 10년이동평균

Dam

age a

mount (1

0 b

illion w

on)

Flooding damage amount

10 years moving average

(10 billion won)

Protruded joint conduit Conduit damage & crack Bent conduit

Conduit sediment Other conduit passing Sedimentation

8/28

Over 226% increase

Insufficient investment for Sewer pipelines Improvement

Investments have been made from 1997 For Sewer pipelines improvement project, but it has been Relatively smaller than that for Sewerage treatment facilities

1. Background & Problems

Out of total length of newly installed sewer pipelines, the ratio of storm water pipelines installation is as low as 6%.

Category Sanitary

drain pipelines

Combined pipelines

Storm water

pipelines Length

(km) 13,823 (67%)

5,620 (27%)

1,197 (6%)

<Nationwide sewer pipelines installation status (2001~2011)>

Investment for Storm water pipelines are significantly lower compared to that for sanitary drain pipelines (Last 5year 6.2 ~ 9.2%)

amount invested for sewer pipelines improvement projects (2006~2010) >

3 Sewerage Policy against Urban Flooding In

vestm

ent budget (N

ational tr

easury

, hundre

d m

illion w

on)

sewer pipeline maintenance, national treasury

Wastewater treatment facility installation, national treasury

Investm

ent ra

tio (

%)

Filthy water conduit

Confluent conduit

Storm water conduit

Total length

Investm

ent fo

r pip

elines

(hundre

d m

illion w

on)

Sto

rm w

ate

r pip

elines investm

ent ra

tio

Filthy water conduit Storm water conduit Storm water investment ratio

9/28


2. Solutions

Localized heavy rains are frequently occurring but the design capacity for Sewer pipeline does not properly reflect it.

※Maximum hourly precipitation in Seoul in July 2011: 113 mm ↔ Drainage capacity: Sewer 65 ~ 75 mm, Drainage pump station 65 ~ 88 mm

Design to efficiently prevent flooding is insufficient, and inefficient operation between Sewerage facilities without organic connections

※ In the design method for sewerage for area prone to floods, insufficient consideration

for water control capability for sewer pipelines, detention storage facilities and

pump station

※ Even though pump station’s discharge capability is sufficient, rainwater cannot be

immediately flow Into retarding basin due to insufficient capacity of sewer pipelines

and thus flooding damage is occurred.

A. Expansion of sewerage to get rid of the areas prone to flood

B. Application of State-of-the-art Design/Operation technique

10/28

Reorganization of sewerage facility standard to cope with the increase in the intensity

of precipitation and the number of days for localized heavy rain is required


2. Solutions

Difficult to make judgment on the ability to cope with urban flooding with existing

Sewer pipelines Distribution rate (Facility extension / Expanded plan) index.

C. Improvement of Flood Damage Prevention System

11/28

A. Expansion of sewerage to get rid of the areas prone to floods

Period 2013 ~ 2022 (10 years)

Target 총 264개소(폐수:144, 하수:120)

Facility

92 areas prone to flood nationwide (Treatment area unit)

Sewer pipelines, detention storage facility, rainwater pump station

Investment

Target

Category Flood criteria Investment targets

1st stage

(2013-2017)

Metropolitan

City ․ Flooded for over 8 times ․ 3 cities, 5 unit areas

City, County ․ Flooded for over 6 times ․ 19 cities & countries, 22 unit areas

2nd stage

(2018-2022)

Metropolitan

City ․ Flooded for 4~7 times ․ 3 cities, 5 unit areas

City, County ․ Flooded for 2~5 times ․ 48 cities & countries, 60 unit areas

< Sewerage Investment Target>

Plan

Ove

rvie

w

1st stage: Flooded for over 8 times in Metropolitan cities, flooded for over 6 times in cities and counties 2nd stage: flooded for 4~7 times in Metropolitan cities flooded for 2-5 times in cities and counties


3. Detail improvement plan

12/28 ※ Number of times for flooding is sewer treatment area unit, and it also indicates th number of times for flood damage for the past 10 years (2001-2011)

Investment ratio for Sanitary drain pipelines Vs Rainwater pipelines

- Current : Sanitary drain water 80% : storm water 20% (2012)

- Plan : Sanitary drain water 60% : storm water 40% (2022)

Funding Plan


Filthy water

conduit

Rainwater

conduit

(6,823 hundred million won)

(1,681 hundred million won)

Filthy

water

conduit

Rainwate

r conduit

Rainwate

r conduit

Rainwate

r conduit 2012 year 2017 year 2022 year

Sanitary

Drain water

Rain water

20%

Sanitary

Drain water

Rain water

Sanitary

Drain water Rain

water

13/28

A-1 Storm water pipelines expansion

In line with the reinforcement of sewer pipelines Installation standard for the prevention of urban flooding, improve sewer pipeline

< improve sewer drain capability >

Reinforce Sewer pipelines installation standard (April, 2011)

: 5~10 years → 10~30 years

Installation of large scale main pipeline for each drainage area as a part of multi-regional flood prevention measure covering a number of administrative districts

<Example of multi-regional sewerage

maintenance > Introduced the concept of basin

sewerage for multi-regional sewerage management in the

Sewerage Act

Installation of detour pipeline to supplement insufficient flow load of existing sewer pipelines

< Concept of detour pipeline to prevent flooding >

Newly install detour pipeline as much as the shortage of sewer pipeline by

utilizing existing pipeline (Introduce simulation technique)


Insufficient sewer drain capability

Expand diameter of pipelines, Increase sewer drain capability

Basin sewerage(New)

River River

Sewerage

Flooded area

Sewerage

Flooded area

River River

Overflow

Detour conduit

Wastewater detention storage facility

14/28

Underground detention storage facility

Rainwater in excess of sewer pipeline Capacity is temporarily stored underground tank

※ Demonstration project : Guri city( in 2006-2008), Saemangeum detention storage facility ( in 2010-2013)

Tunnel type detention storage facility

installation for the replacement of sewer pipeline in inner city area Installation at the area where underground detention storage Facility is difficult to install

Wastewater detention storage facility: Currently 22 places(8,000㎥) → By 2022 187 places(5 million㎥)

Reinforce treatment of sewage overflow and reuse of detention storage rainwater

※ Demonstration project : Sinwol area in Seoul (2011-2015, 121.6 million USD)`


A-2 Expand Wastewater Detention Storage Facility

linked treatment

linked treatment

15/28

Increase the capacity of pump station interlocking with sewer pipeline Rainwater pump

station

Relay pump station

construction of Relay pump station when it is inevitable to secure fast drainage and drainage capacity in existing pump station

< Insufficient capacity of Pump Station>

< Replace with large capacity pump>

< Newly construct additional pump station>

※ Pump Station: Currently 476 places → 81 places to be replaces or expanded by 2022


A-3 Expansion of Rainwater Pump Station

16/28

< Concept of Simulation technique to cope with flooding >

Develop site-specific technique by applying dual drainage system simulation to cope with flooding with simultaneous modeling for the outflows of surface water and sewer pipeline together

After demonstration test(2012-2015) at 6 cities(including Seocheon-gun) depending on the size of city and the type of sewer pipeline, and then expand nationwide afterwards

Field test

B-1 Application of Simulation technique to cope with Flooding


B. Application of State-of-the-art Design/Operation technique

Development of technique

<Past state of flooding > <application of expanded diameter for sewer pipeline>

< application of sewer pipeline + Detention storage facility + pump station >

flood level

flood level

Trunk conduit capacity increase

Trunk conduit capacity increase

Rainwater storage tunnel


Improvement of pump station

17/28

B-2 Introduction of sewer pipeline network control system (Real Time Control)

Establish network for automatic control of sewerage facility (sewer pipeline-detention storage facility-pump station- wastewater treatment plant)

Networking

At the time of precipitation, sewer pipeline , detention storage facility, pump station sensors are automatically monitored by central control center of Sewerage Treatment Plant Central control center monitors and controls sewer pipeline, pump station and detention storage facility

Management System

Store the only storm water which is in excess of sewer pipeline capacity in the detention storage facility

Change of counter-flooding mode in summer season (June ~ September)

Operation of water quality mode in winter season, spring and autumn

Initial storm water with high density should go through detention storage before discharging to river.


18/28


Weather forecast equipments

Weather information

Storm water pipeline

Water level gauge

Wastewater treatment plant

Wastewater detention storage

facility

pump station

River linked treatment

Concept of sewer pipeline network control

system

Central control center

19/28


• Upward adjustment of probability years considering the location of major facilities, area of drainage area and economy (5-10 years → 10~30 years)

sewer pipeline

• Together with the adjustment of probability years for sewer pipeline, adjust the probability years for Pump station as well (30~50 years)

Storm water pump station

Comparison of Probability years by counter-flooding facility River: 100~200 years for national rivers including 4 major rivers / 50 ~ 80 years for regional rivers Sewerage: 10 years for branch sewer pipeline / 30 years for main sewer pipeline (For past , 5 years for branch and 10 years for main sewer pipeline), 30~50 years for storm water pump station

<Existing> Focused on

sanitary transfer

<Future> Focused on Rainwater drainage

role Change

• Increase in investment for storm water sewer pipeline improvement to prevent urban flooding instead of increase in sanitary drain pipeline (Expand up to 40%)

Change of the direction for sewer pipeline policy

< concept of sanitary drain pipeline improvement >

C-1. Reinforcement of Sewerage facility standards

C. Improvement of policy against flood Damage

20/28


Major contents of priority

control area for sewerage

maintenance

Overview of Priority Control Area

Definition of Priority Control Area

The area designated by the Minister of Environment among the areas which have the possibility of deteriorating water quality of water basin or have the possibility of flood damage to occur or actual flood damage area

C-2. Introduction of Sewerage Priority Control Area Designation System

Counter-measures

▪ Establish sewerage maintenance measures (1 year after the announcement by the Minister of Environment)

▪ Scope of designation: Drainage area or sub-drainage area ※ In case whole sub-drainage area is not eligible to apply priority control area, the area covered by the application only

Scope of designation

Designation criteria

Application for

designation

▪ Application (local government) → Designationㆍ Announcement (Ministry of Environment)] ※ Document to be submitted: Application for Priority control area designation

▪ Actual flooded area (or possible area) from overflow of sewage

▪ Actual flooded area (or possible area) due to defective sewer pipeline

▪ Water quality deteriorated area(or possible area) due to overflow

of sewage

21/28


Procedures for designation

Minister of Environment designated as priority control area for the area which has the possibility of flood damage and water quality deterioration(or their possibility)

Minister of Environment designates at the request of the mayor of local government

Establish maintenance measures

mayor of local government establishes sewerage maintenance measures when designated as a priority control area

Budget support

Minister of Environment supports budget required for the implementation of sewerage maintenance measures

Release of designation

Minister of Environment releases the designation when the reason for designation was not satisfied

Designation of priority Control Area (Article 4-3 of the Sewerage Act)

Contents included in the maintenance

measures

1. Objective of sewerage maintenance, performance period, and plan for expansion, maintenance and management of sewerage

2. Status of precipitation and flood damage, and status of sewerage maintenance

and its problems

3. Connectivity with other plans

4. Annual investment plan and funding plan

5. Other items announced and acknowledged to be necessary by Minister of Environment

Establishment of Sewerage Maintenance Measures (Article 1-4 of Enforcement Decree of the Sewerage Act)

22/28


Rainwater Use Facility

Installation of rainwater reuse facility at the buildings with a certain size is obligated pursuant to the law concerning the promotion of water reuse (Implemented in June 2011)

C-3. Expansion of Rainwater Use Facility Installation

- Roof area: Over 2,400 m2 → Over 1,000 m2 - Target facility : Athletic facilities → Public work facility, public offices were added ※ Capacity of rainwater use facility : Currently 54 thousand m3 → 460 thousand m3

in 2020 (Increase by 8.5 times)

< Rainwater using method> < Rainwater use facility of Sangam World-cup Park in Seoul>

23/28


1. Sewerage Maintenance Project for the prevention of Urban Flooding (2012)

• 「Government’s joint measures on disaster management to cope with climate change (Dec. 9, 2011) • Selection of demonstration project target area (Feb. 24, 2012): 6 places including Bucheon city • Carried out demonstration project design work (Feasibility study plan May 2012., Basic design· implementation design, Jan.-July 2013)

Major sequence of Implementation

Project cost for model project area

Category demonstration project cost (million USD)

Total Kimhae city Bucheon city Andong city Cheonan city Boseong-gun Seocheon-gun

Grand total 230.0 36.3 44.1 40.9 33.7 31 44.0 Central

government budget

161.0 25.4 30.9 28.6 23.6 21.7 30.8

Local government budget 69.0 10.9 13.2 12.3 10.1 9.3 13.2

Characteristics of maintenance

Sewer pipeline Pump station Detention storage facility

Metropolitan area Separated Sewer area sewer pipeline maintenance Expand pump station

Metropolitan area Combined Sewer area construction of Wastewater tunnel Semi-basement household arrangement

Medium-size city area Separate sewer area(planned) Simultaneous arrangement of rainwater and filthy water New construction of pump station

Medium-size city area Separate sewer area storm water pipeline maintenance New detention storage facility construction

Small-size city area Separate sewer area storm water pipeline maintenance

Small-size city area Combined Sewer area Combined Sewer maintenance New construction of pump station

24/28


Overview of Project

<Mimetic diagram> Anticipated Effect

• Possible to reduce flood damage at upstream and downstream areas

• To cope with occurrence frequency of rainfall increase from 10 year to 30 year (hourly 45 mm → 94 mm)

•Elimination flooding in the area around Gangseo and Yangcheon-dong

• By minimizing the incurrence of combined sewer overflow (CSOs), provide pleasant waterfront space through the improvement of river water quality of Anyang River

Purpose of Project

• Install a deep drainage tunnel to solve insufficient capacity of main sewer pipeline of Mok-dong rainwater pump station so that flooding in upstream and downstream is prevented by fast outflow upstream rainwater to pump station

Size of Project

• Detention storage capacity: 150,000㎥, Diameter of conduit: 7.5m, Length: 3.38km, Underground depth: 35~40m

Total Project Cost

• 121.6 million USD (National treasury 30.4 million USD, local government budget 91.2 million USD)

2. Sinwol deep drainage tunnel project in Seoul

inflow of rainwater

Securing of discharge capability

25/28

5 Anticipated Effects

Elimination of Areas prone to flooding through the expansion of sewerage

< Prospect of Area prone to Flooding>

< Reinforcement of Rainwater Elimination function of Seoul (Probability years 50 years)>

Reinforcement of the Role of Sewerage for the prevention of flooding

Pro

ne t

o f

lood

Flo

od p

ossib

ility

Metropolitan City General city and gun

2012 year 2017 year 2022 year

Precipitation effluents 26,103 Thousand tons

sewer pipeline

Others

Wastewater detention storage

facility

Pump Station

River

Pump Station

sewer pipeline

Tunnel type detention storage

facility


Underground detention storage facility

Flood discharge

26/28

하수처리시설

Arrangement of houses in lowland

Drainage pump facility maintenance

sewer pipeline Maintenance

General type detention storage facility

Deep tunnel type Wastewater detention storage facility

Pressure pipe

filthy water conduit

4 Anticipated Effects

Preparation of space for urban live that is safe from flooding

Semi-basement building

Dispersal type Wastewater

treatment plant

Rainwater use facility

Lowland semi-basement house Rainwater

flooded facility

Pump station

River sewer

pipeline


Wastewater treatment facility

Conduit sinkage

Conduit damage

Soil sedimentation

Conduit deformation

Internal defective

maintenance

Water control capability

restoration

Insufficient water control capability

Expansion of conduit diameter

Water control capability

restoration

Wastewater in excess of

capacity

Inflow conduit

Connected treatment

(at the time of blackout)

Temporary storage


27/28

Thank you!

28/28

台灣下水道協會首頁 - 슬라이드 1 SESSION/2.pdfInvestment for Storm water pipelines are significantly lower compared to that for sanitary drain pipelines (Last 5year 6.2

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