The role of rainwater tanks in reducing vulnerablity during land and water related emergencies

Wellington is extremely vulnerable to large earthquakes since it is bisected by large active faults and isolated in terms of supply lifelines. The potential for loss of water and food supplies is real and could render large areas uninhabitable for weeks to months. The purpose of this study was to explore the options for the installation of rainwater tanks in critical areas in the Wellington Region before and after a damaging earthquake. The importance of securing emergency water after a large earthquake is indisputable and this study was especially concerned with the applicability of roof water harvesting as a sustainable alternative water supply option.

The study had the following specific objectives:

• To explore the benefits of installing rainwater tanks.
• Identify likely areas to site rainwater tanks.
• Identify logistical implications for transporting and installing rainwater tanks.
• Identify technical issues including cost estimates of tanks.
• To examine community needs, perceptions and expectations.
• To examine security of supply issues.
• Identify minimum water treatment requirements.

Roof-collected rainwater can contribute significantly to a sustainable water strategy in times of disasters like earthquake, when the lifelines of centralised water infrastructures are compromised. The strategic placement of rainwater tanks at accessible sites presents several advantages to affected communities – not least that the critical lifeline of water is immediately available for emergency response.