The Effect of Decentralized Rainwater Tank System The Effect of Decentralized Rainwater Tank System on the Reduction of Peak Runoffon the Reduction of Peak Runoff

- A case study at M village -- A case study at M village -Mooyoung Han*, Soyoon Kum*, Jeoungyoun Kim*, Jungsoo Mun** Mooyoung Han*, Soyoon Kum*, Jeoungyoun Kim*, Jungsoo Mun**

* * Department of Civil and Environmental Engineering, 35-517 Seoul National University, Daehak-dong, Department of Civil and Environmental Engineering, 35-517 Seoul National University, Daehak-dong, Kwanakgu, Seoul, 151-744, Korea Kwanakgu, Seoul, 151-744, Korea (E-mail: myhan@snu.ac.kr)(E-mail: myhan@snu.ac.kr)

** ** Senior Researcher, Plant Business Headquarters, Lotte Engineering & Construction, Seoul, KoreaSenior Researcher, Plant Business Headquarters, Lotte Engineering & Construction, Seoul, Korea

IntroductionIntroduction

This research was supported by a research fund (2Z03401) from Engineering Research Center at Seoul National University.

MethodologyMethodology

ConclusionsConclusions1) If rainwater tank is installed into existing urban drainage system, peak flow rate reduction effect is shown and inundation damage can be prevented.

2) Although total storage volume of rainwater tank is same, increment of tank number induces more peak flow rate reduction.

3) With disposition type of rainwater tank, peak flow rate reduction effect is change. In the case of research area, Upper-mid rainwater location is the most

effect placement.

Results and DiscussionsResults and Discussions

Need New water management paradigm!!

Pipe extension

Newly- Pipe laying

Large scale detention pond

High cost & energyuncertain, unsustainable

resident complain

Full!

peak flow max capacity≫

Building rooftop Drainage pipe

RainfallRainfall DrainageDrainage Current measures

& limitation

Types ofTypes ofCentralizationCentralization

Rainwater tankDetention basin

Runoff area

Time of concentration

Flow control

30 min ~ hours < 10 min

Detention Retention

10 ~ 100 ha < 1 ha

Concept of DRMS(Decentralized Rainwater Management System)

Input Output

Simulation

Governing Equation

Entry conditionsBoundary condition

1. Runoff Mode2. Sanitary Mode3. Hydraulics Mode

Meteorological data(Precipitation, Evaporation)

Catchment data(Catchment characteristics, Infiltration)

Channel data(Conduit characteristics)

Structure data(Retention tank, Weir, Orifice)

Hydrograph (Channel, Outfall)

Water level curve (Manhole, Channel, Retention tank)

Runoff volume velocity curve(Subcatchment, Conduit)

Flooding level, Area(Retention tank, Weir, Orifice)Extract data From ArcGIS

Case 1 2 3 4 5 6

㎥ × unit 0 3,000×1 1,500×2 1,000×3 750×4 600×5

Condition 1 : RST volume and unit ( Total volume : 3,000※ ㎥ )

Centralized Decentralized

Condition 2 : Location ( Application to real flooded area as priority)※

<Method of case selection>

M village, Suwon city, Gyeong-gi province, Republic of Korea

<Method of case selection>

CaseUpper-region

Mid-region

Down-region

11,000 ㎥

×30 0

2 01,000 ㎥

×30

3 0 01,000 ㎥

×3

41,000 ㎥

×11,000 ㎥

×11,000 ㎥

×1

51,800 ㎥

×1900 ㎥ ×1 300 ㎥ ×1

6 900 ㎥ ×11,800 ㎥

×1300 ㎥ ×1

7 300 ㎥ ×11,800 ㎥

×1900 ㎥ ×1

8 900 ㎥ ×1 300 ㎥ ×11,800 ㎥

×1

Case 5 : UWS (U-type) Case 6 : MWS-a (M1-type) Case 7 : MWS-b (M2-type) Case 8 : DWS (D –type)

Localized Heavy Rain

Floodin Rural Area

Floodin Urban Area

Overflowing Repeated Disaster

Localized Heavy Rain

Conventional Conventional SystemSystem

Localized Heavy Rain

Localized Heavy RainDecentralized Decentralized SystemSystem

Reduction of flow

Reduction of flow

Detention Infiltration & catchment facilities

Infiltration & catchment facilities

<Modeling results> <Modeling results>