Newsletter and Technical Publications
<Proceedings of the International Symposium on Efficient Water Use in Urban
Areas
- Innovative Ways of Finding Water for Cities ->
B. Session 2: Harvesting and Utilisation of Rainwater
Moderator: Mr. John H. Neate, Strategies for Change, Canada
Rapporteur: Mr. Makoto Fujita, Associate Programme Officer, UNEP-IETC
Presenters:
(1) Prof. Adhityan Appan, Nanyang Technological University, Singapore
(2) Mr. Klaus W. König, Professional Association for Water Recycling and
Rainwater Utilisation, Germany
(3) Dr. Makoto Murase, Chief of Environmental Protection Section, Sumida City
Government, Japan
The “Harvesting and Utilisation of Rainwater” session addressed a wide
range of case studies, including applications in villages and large cities at
the household, community and institutional / commercial facility levels. Various
issues were presented, including: planning and design of rainwater
collection and utilisation systems; water quality and regulatory aspects;
costs and innovative financing alternatives; public acceptance;
and institutional barriers. The session also emphasised the need for
integrated approaches to improve water resource management leading to the
establishment of a more resilient, autonomous hydrological cycle at the local
level.
Key Points Presented:
Planning & Design
- Urban catchment integration is an important aspect of rainwater collection
and utilisation.
- Rainwater collection and utilisation are effective flood control
strategies.
- Rainwater collection and utilisation schemes are optimal when implemented
in conjunction with water demand management, as well as measures to enhance
aquifer recharge.
- A decentralised water supply system is more flexible and resilient than
conventional, centralised systems.
- Measures should be taken to establish autonomous water systems that
are not dependent on water resources outside a given watershed.
- The incorporation of dual mode systems and adequate storage are key
considerations.
- Smaller rainwater catchment systems are excellent additions when integrated
with existing conventional water supply systems.
- The standardisation of systems and equipment design can significantly
enhance the implementation of rainwater collection and utilisation.
- Durability and reliability of infrastructure and equipment are also key
considerations.
Water Quality & Regulatory Aspects
- Water quality is a significant but manageable issue; particular care must
be taken to ensure that potable water is not negatively affected by proposed
rainwater utilisation schemes.
- World Health Organisation (WHO) Guidelines should be considered in
any proposed rainwater utilisation scheme.
- Research and development related to rainwater quality should continue.
Costs & Financing Alternatives
- With rising water prices, the economics of rainwater utilisation are often
very attractive, particularly if the system is designed and built properly.
- The economic benefits of rainwater utilisation and savings in water
consumption are often greater for institutional investments (like airports,
schools, etc.).
- To lower the overall costs of rainwater collection and utilisation, simple
roof water collection systems may be preferable.
- Innovative approaches are needed to finance rainwater collection and
utilisation systems.
- Appropriate subsidisation of users may in some cases accelerate the
implementation of rainwater collection and utilisation.
Public Acceptance & Institutional Barriers
- Public awareness and education are essential in order to improve
acceptance of rainwater collection and utilisation.
- Efforts should be made to change public perception of water from being
viewed as a nuisance to being viewed as an asset.
- Metering both potable water and rainwater utilisation can create awareness
of these valuable resources.
- Demonstration projects are key for improving public acceptance and
assisting in the removal of institutional barriers.
- It should be recognised that in some cases existing water providers may be
threatened by rainwater collection and utilisation options, particularly
where excess capacity already exists.
- To promote rainwater utilisation, basic policies, implementation
strategies, technology development and networking are required.
Session Recommendations:
- Rainwater collection and utilisation should be viewed as an
effective flood control strategy.
- Rainwater collection and utilisation schemes should be implemented
in conjunction with water demand management, as well as measures to
enhance aquifer recharge.
- Measures should be taken to establish autonomous water systems that
are not dependent on water resources outside a given watershed.
- Smaller rainwater catchment systems should be integrated with
existing conventional water supply systems where possible.
- Particular care must be taken to ensure that potable water is not
negatively affected by proposed rainwater utilisation schemes.
- World Health Organisation (WHO) Guidelines should be considered in
any proposed rainwater utilisation scheme.
- Research and development related to rainwater quality should be
supported and encouraged.
- Innovative approaches should be sought to finance rainwater
collection and utilisation systems.
- Public awareness and education are essential to improve acceptance
and implementation of rainwater collection and utilisation.
- Demonstration projects should be undertaken to improve public
acceptance and assist in removing institutional barriers.
- To promote rainwater utilisation, basic policies, implementation
strategies, technology development and networking are required.
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