The Central Otago Environmental Society (COES) says the Otago Regional Council has come ‘perilously late to assessing both the degradation and over-allocation of Otago waterways’.

The Otago Regional Council (ORC) last month received a significant state of the environment report on river and lake water quality in the region. 

The report analyses the state and trends of freshwater over the period from 2000 to 2020.

The study reports on the state of water quality on a site-by-site basis, relative to nationwide targets specified in the National Policy Statement for Freshwater Management 2020. 

It also assesses water quality trends at each site where there is sufficient data, and across Otago as a whole.

Central Otago Environmental Society (COES) Chair Mike Riddell says the ORC has come “perilously late to assessing both the degradation and over-allocation of Otago waterways”. 

“A current case in point is the woeful state of the Manuherekia and her tributaries,” he says. 

“However, it is good to see that at long last some of the science is being commissioned by the ORC, and the vast majority of the data demonstrates what people concerned for the Central Otago environment have known for some time. 

“It is gratifying that the National Policy Statement for Freshwater Management 2020 (NPSFW) has galvanised the ORC to begin monitoring both the health and poor flows of many of our waterways. 

“COES has been represented on the Manuherkia Reference Group (a working group of the ORC) for some time now, and has consistently advocated for both the remediation of our rivers and the restoration of their natural flow. 

“Many of the problems are historical, and regulatory groups such as the ORC have been slow to address them. 

“Ordinary people are often bemused by the science, but they recognise the fact that something is drastically wrong with our rivers, and want to see them cleaned up. 

“We would like to encourage the ORC to continue taking Te Mana o the Wai seriously - not only through analysis but through fulfilling its responsibilities to be a guardian of our natural environment.”

ORC General Manager Strategy, Policy and Science Gwyneth Elsum says the information in the report was valuable for ORC and the wider community as it updates the knowledge of water quality across Otago.

“This report largely reflects the patterns we have seen in the past, which tell us that water quality is best in the headwaters and at higher elevations, but it suffers at sites in smaller, low-elevation streams that drain pastoral or urban catchments.

“That spatial pattern of water quality in Otago will inform the development of our new Land and Water Regional Plan, which divides the region by catchment into freshwater management areas.

“This information will also support ORC and the community to implement other water quality improvement initiatives,” Gwyneth says. 

The report considers 10 water quality variables and indicators at over 120 monitoring sites in Otago: 110 river sites, and 22 sites and depths at nine lakes.

The report does not analyse the drivers for water degradation trends, due to the lack of detailed information that ORC currently holds on land use and land management changes at a local or catchment scale. 

In the report, it states “there is a lack of detailed information held by Otago Regional Council on local or catchment scale land use change or land management practice changes. 

“This severely limits Council’s ability to comment on drivers of trends evident across Otago.”

ORC recently formed a new science team to develop its knowledge in this area.

The ‘State and Trends of River and Lake Water Quality in the Otago Region 2000-2020’ report can be viewed online here. 

The analysis in last month’s report will be repeated next year with data up until June 2022, to give ORC a clear baseline to evaluate the effectiveness of its upcoming Land and Water Regional Plan in the future.