The Otago Regional Council (ORC) report on states and trends of freshwater in Otago has revealed increasing levels of E.coli and declining health of the Manuherekia (Manuherikia River). 

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

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

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.

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.

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 our knowledge of water quality across Otago. (Continue reading below).

Advertisement

“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 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. 

“This is likely to be addressed by requirements in the NPSFM 2020, which requires that freshwater is managed in an integrated way that considers the effects of the use  and  development  of  land  on  a  whole-of-catchment  basis,  including  the  effects  on  receiving environments.”

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 this 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.