Niwa’s water proposals taken on board: ORC

A DETAILED review of all of the Otago Regional Council’s lake and river water quality monitoring network has recommended changes be made to ORC practices, including in its three major alpine lakes.

The ORC commissioned Niwa to conduct the review last year to futureproof the programmes so they were fit for purpose in terms of the site network, monitoring variables and technology.

ORC resource science manager Dean Olsen said ‘‘part of the drive behind getting the report done was it was good to review practices from time to time, and another was because the 2017 amended National Policy Statement for Freshwater Management has established expectations from central government about local government water monitoring’’.

The ORC monitors water in nine lakes, including Wakatipu, Wanaka and Hawea.

The Niwa report recognised there were resourcing and logistical constraints on monitoring programmes that had led to the current mix of outlet and onlake monitoring sites.

The onlake monitoring of the alpine lakes had been monthly for two or three years, every 10 years. The report said: ‘‘In light of their very high regional (and national) values, and potential for change in condition, ongoing monthly sampling of open water sites on Lakes Wakatipu, Wanaka and Hawea is highly recommended.’’

The report also recommended deploying an automated monitoring buoy in each of those lakes.

Buoys with fixed sensor strings can record measurements down to the lakes’ maximum depths (maximum depth 384m) 24 hours a day, seven days a week all year round.

Dr Olsen said the ORC was already one year into a threeyear monthly monitoring programme of the three largest and deepest lakes.

‘‘We have now extended that out so that it is a perpetual part of our programme, as well as quarterly sampling of some of our shallower lakes.’’

He said the ORC had budgeted for deploying buoys in the 201828 Long Term Plan but Niwa had made it ‘‘quite clear’’ buoys were useful but did not replace a boat sampling programme, and ‘‘the greatest urgency was to establish that’’.

Dr Olsen said the ORC had taken all Niwa’s recommendations on board, had moved into discussions about funding and would shortly be taking a paper to the council that will outline the work.