Author(s): Induka Werellagama; Gregory De Costa; Binil Davis
Linked Author(s):
Keywords: Coastal reservoir; Drinking water; Climate change; Water storage; Civil defense
Abstract: In New Zealand, some cities must impose water restrictions in the summer. In the event of a disaster like an earthquake, the water supply pipelines may rupture and water supply to main cities can be disrupted up to one month. To give reliability to the water supply, several large reservoirs are used. There are consenting issues, including the residents’ fear of dam failure, leading to another disaster. This concept paper looks at the viability of storing fresh water in the coast, in a coastal reservoir for two cities Wellington and Christchurch. A coastal reservoir is usually placed at the estuary of a stream or a river, storing freshwater. Modern examples of large sea-reservoirs include the saltwater intrusion barriers in Singapore, Adelaide (Australia), China and in Netherlands. The advantage of a coastal reservoir is that the total cost of the reservoir is much less than an upstream reservoir, with no land being inundated. The dam can be flushed (if required) easily. Also, the environmental consequences of a dam rupture (if any) are lesser. If membrane technologies like Reverse Osmosis (RO) are considered for water treatment, it is more viable to treat with fresh waters from a coastal reservoir, than doing RO with full strength sea water. This paper reviews dam building methods from literature. If a Wellington or Christchurch trial is successful, building similar reservoirs can be investigated for other cities like Whakatane (where saltwater intrusion is an issue) or even for Auckland which has water shortages/ restrictions in summers.
Year: 2020