Comparison of Relevant Aspects in Rainwater Harvesting Practice between Two Metropolises: Tokyo & Selangor

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1 Comparison of Relevant Aspects in Rainwater Harvesting Practice between Two Metropolises: Tokyo & Selangor A.R. Nafisah and J. Matsushita Division of Regional Environment System, Graduate School of Engineering, Shibaura Institute of Technology

2 OBJECTIVES OF THE STUDY 1. Investigate the welldeveloped RWH practice in Tokyo from several aspects 2. Compares Selangor s efforts on such aspects 3. Proposal of betterment for RWH practice in Selangor Mainly in Sumida City RELEVANT ASPECTS: Policy & planning Design Technological Social matters

3 BACKGROUND Per capita water consumption peaked in 1972, later steadily reduced after the introduction of Save Water Policy package in 1973 Per capita water consumption is in increasing trend needs measures such as taken by Tokyo to reduce the consumption

4 Category Total Save Water Policy Total Water Conserved (l/p/d) Remarks Demand side Save-water Type Flushing Toilet Device (SWTFTD) % (household with SWTFTD) x 49% (conservation rate) x 14% (water for toilet flushing from 351l/p/d consumption) Save-water Type Tap (SWTT) % (household with SWTFTD) x 25% (conservation rate) x 28% (water passing through tap from 351l/p/d consumption) Wastewater Recycling (WWR) & Rainwater Harvesting (RWH) 6.6 (WWR) (RWH) = 6.63 WWR= 85,400 m 3 /d (recycled amount) 12.9 mil RWH= 13,000 m 3 (total rainwater tank capacity) x 10 times usage/year 365 days 12.9 mil Awareness Campaign Under Investigation - Supply Side Leakage Reduction ,000m 3 /d (leakage reduced) 12.9 mil In-pipe Pressure Reduction Under Investigation - TOTAL 181 Effects from Save Water Policy Package in Tokyo Although RWH is not utilised much in Tokyo, there has been some serious investigation into the potential role that RWH could play in water supply, flood prevention and disaster mitigation strategies (J.Gould, 1999) In reality mainly this amount is for Sumida-ku. Thus, roughly about 1.8 l/p/d of water can be conserved if per head basis is calculated for Sumida-ku only.

5 History & Developments of RWH in TOKYO YEAR RWH HISTORY & DEVELOPMENTS 1983 RWH was introduced in Sumida-ku (model system is in the building for young children 1985 National Sumo Arena was completed with utilization of large scale RWH (1,000 m³ underground rainwater tank) 1988 Rojison a communal RWHS is installed in Mukojima area in Sumida Ward 1994 International Rainwater Conference was held (about 8,000 participants from 16 countries joined the conference) Sumida-ku formulate planning guidelines for RWH promotion - Subsidy system for rainwater tank was initiated - Mandatory system for RWH was established - People for Rainwater (PR) was established 1996 Network of local government (Rainwater Utilization Liaison Council ) to promote RWH is instituted: 125 local government joined the network International Association of Local Government awarded Sumida Ward for the best practice of RWH - Japan Business Association for Rainwater Utilization was set-up 2001 RWH Museum was opened in Sumida City (the world s first museum of its kind) 2005 Tokyo International Rainwater Conference was with Sumida Ward s coordination 2006 Sumida-ku formulates the Environmental Local Ordinance that stipulate RWH promotion in the basis of collaboration among stakeholders (developer, public, private) 2007 Sumida-ku formulate Environmental Planning in which RWH is stipulated as one of high priority measure 2008 The first congress of rainwater network was constituted

6 History & Developments of RWH in Selangor YEAR RWH HISTORY & DEVELOPMENTS 1998 Government state the interest in RWH after experiencing severe drought in Klang Valley 1999 Initial phase of RWH policy in Malaysia: the introduction of Guidelines for Installing a Rainwater Collection and Utilization System Ministry of Housing & Local Government prepared a cabinet paper to encourage government buildings to install rainwater collection & utilization system - National Hydraulic Research Institute of Malaysia (NAHRIM) was established to conduct research in all water hydraulic & water environment aspects including rainwater harvesting National Urbanization Policy (NUP) was formulated which emphasize on the use of alternative water resources including rainwater harvesting and water recycling. For the long term plan, it aims at installing RWHS in new government buildings and schools - the government announced to make rainwater harvesting mandatory to large buildings like factory, school or bungalow

7 RWH Policy & Planning Aspect Overview TOKYO Subsidy system Small Size Tank (less than 1cu.m) TANK SIZE Medium Size Tank (> 1cu.m to < 5cu.m) Large Size Tank/ Underground Tank (more than 5cu.m) SUBSIDY DETAILS 50% of the tank cost; maximum subsidy amount = 40,000 Maximum subsidy amount = 300,000 Maximum subsidy amount = 1 million Semi-Mandatory system For new building with floor areas > 10,000m², TMG encourages the owner to install RWHS. Previously, it was not mandatory (but not oppose by building owners). Only recently become mandatory. It leads to increasing number of RWH installation/utilization in Tokyo Registration system TMG execute registration system, wherein if the company is registered, they receive subsidy for installing RWH tank. Thus, organized database for the RWH implementation can be recorded for the purpose of research & developments and future reference

8 RWH Policy & Planning Aspect SELANGOR Overview (CONT D) There are no subsidy system, mandatory system or registration system

9 RWH Design Aspect Overview TOKYO Tank Design [ The Size of Storage Tank = Population in the Building x 50litre x 3 days ] Or [ The Size of Storage Tank = Roof Area x 1.5m (Average Rainfall in Tokyo) 12 months ] Harvested Water Quality Design For the quality of harvested rainwater, the design is based on the standard set by Tokyo Health Office. The measures includes on the existence of bacteria such as e-coli, chloride contains, the ph value, odour and turbidity of the water

RWH Design Aspect Overview SELANGOR For tank design (Tangki NAHRIM Software) NAHRIM had built-up the software as a guide in estimating the size of rainwater tank.

10 RWH Design Aspect Overview SELANGOR For tank design (Tangki NAHRIM Software) NAHRIM had built-up the software as a guide in estimating the size of rainwater tank. It can predict: amount of rainwater captured total rainwater volume delivered reliability of the system coefficient of rainwater utilization storage efficiency percentage time of tank empty Twenty years of rainfall data for different cities/towns throughout Malaysia are available in this software * While for harvested water quality, it is compared with World Health Organization (WHO) s standard

RWH Technological Aspect Overview TOKYO TMG encourage RWH product makers to manufacture ready made system - complete package system (easy installation

11 RWH Technological Aspect Overview TOKYO TMG encourage RWH product makers to manufacture ready made system - complete package system (easy installation & reduced cost) Remarkable advances in RWH technology in Tokyo complete RWH package system *Source: (accessed 20 th May 2009)

RWH Technological Aspect Overview SELANGOR (CONT D) The available technology for RWH in Selangor is still the separate subsystem An example of

12 RWH Technological Aspect Overview SELANGOR (CONT D) The available technology for RWH in Selangor is still the separate subsystem An example of RWH installation in Selangor separate system *Source: House.pdf (accessed 15 th May 2009)

13 RWH Social Aspect Overview TOKYO

14 RWH Social Aspect Overview SELANGOR (CONT D) There are no RW Museums, People for rainwater Or other social aspects measures taken such as being practiced in Tokyo

15 RESULTS AND DISCUSSION ASPECTS TOKYO SELANGOR Policy & Planning Subsidy System Registration System Mandatory System Guidelines for Installing a Rainwater Collection and Utilization System Design Tank Sizing (2 formulas) Harvested Rainwater Quality (standard set by Tokyo Health Office) Tangki NAHRIM (tank size) Harvested Water Quality (WHO standard) Technological Complete Package Tank System Separate Subsystems Social Matter Rainwater Museum Rainwater Awareness Programme for School Children People for Rainwater Rain Library Community s Involvements Consumer Education & Information to encourage RWH

16 CONCLUSION

17 THE END THANK YOU

Comparison of Relevant Aspects in Rainwater Harvesting Practice between Two Metropolises: Tokyo & Selangor

Comparison of Relevant Aspects in Rainwater Harvesting Practice between Two Metropolises: Tokyo & Selangor A.R. Nafisah* and J. Matsushita* * Division of Regional Environment System, Graduate School of