Management of Auckland's water supply lakes reviewed
Recently, NIWA reviewed aspects of raw water management for the ten lakes supplying Auckland’s water.
Watercare Services Limited, which operates the lakes, has extensive and well documented operational procedures for water collection, treatment, and water quality monitoring. The water consistently meets the required drinking water standards, but there have been a number of complaints in recent years about its taste or smell. Watercare has quickly located the source and taken remedial action on each occasion.
NIWA’s brief was to recommend improvements to the lakes monitoring programme and raw water management, taking into account the risks and benefits. We looked, firstly, at the historic lakes monitoring dataset and the current monitoring and sampling programme. Secondly, we identified likely causes of ‘taste and odour’ incidents and factors which help predict when such incidents are likely to occur. Thirdly, we reviewed the current raw water management programme, including aeration, lake inspection and reporting, and abstraction levels.
Each week, NIWA now looks at what each lake is doing, based on Watercare’s monitoring, and provides guidance on how to manage the mix of abstractions that go into the water treatment station.