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Major benefits as well as costs in rivers clean up

17 Nov 2015

Healthy Rivers Wai Ora



A new report outlines how there will be extensive benefits as well as costs from work to restore and protect the health of the Waikato and Waipa rivers under the Healthy Rivers: Plan for Change/Wai Ora: He Rautaki Whakapaipai project.

And a second report, following peer review of earlier modelling, shows that at least some initial steps towards restoring and protecting the rivers can be taken “relatively cheaply” and with a manageable economic impact.

“These reports outlining the gains to be made under various river improvement scenarios, plus the modelling of potential financial impacts of change, are key bits of information that will help the Health Rivers/Wai Ora project move forward,” said Bill Wasley, the independent chair of the multi-sector Collaborative Stakeholder Group (CSG) working on river health solutions.

“For example, it is encouraging to see that we can potentially at least make a start on the journey towards our goals without having too much economic impact.

“Our challenge over coming months will be to use this new data - and the feedback we’ve had from recent public workshops and a survey - to develop a recommended change to the Waikato Regional Plan so that we can better improve the rivers, taking into account the expected pluses and minuses of different courses of action.

“This is leading edge stuff nationally being carried out right here in the Waikato and we’re determined to get the best possible solution that works for our region and the environment. We stress again that the models are just that, they are not suggested outcomes, and making improvements in water quality is expected to be achieved over time, not in one king hit,” said Mr Wasley.

The first report – the Integrated Assessment Baseline and Scenarios – outlines expected benefits of making change and includes data on potential financial costs. New features of this report include evaluation of the impacts of changes on a range of Māori, environmental, social and economic indicators.

Integrated Assessment Baseline and Scenarios again looks at five river health protection scenarios:

  • Scenario 1: Making both rivers swimmable and fishable everywhere (equivalent to meeting the legally binding Crown-iwi Vision and Strategy for the rivers)
  • Scenario 2: No further degradation and improving to minimum acceptable states
  • Scenario 3: Some general improvement for swimming, taking food and healthy biodiversity
  • Scenario 4: No further degradation
  • ‘Stepping stones’ to achieving Scenario 1 over time.

Some of the report’s examples of river health benefits under each scenario include:

  • Scenario 1: Better overall water clarity, less sickness-causing bacteria and improvements in ecosystem health. Also, better knowledge of swimming places and increased recreation use, as well as reductions in pest weeds and fish, and improvements in edible food.
  • Scenario 2: Better clarity, mostly in the lower parts of both rivers, and bacteria reductions, and some improvement in ecosystem health, as well as better knowledge of swimming places and increased recreation use, reductions in pest weeds and fish, and improvements in edible food.
  • Scenario 3: Better clarity generally supporting an increase in swimming suitability and less bacteria. Better knowledge of swimming places and increased recreation use, as well as reductions in pest weeds and fish, and improvements in edible food.
  • Scenario 4: No clarity or bacteria improvements, and no benefits to ecosystem health. Better knowledge of swimming places and extra recreation use.
  • ‘Stepping stones’ (10, 25, 50 and 100 per cent over time): Improving trends for clarity, bacteria, pests and ecosystem health from 10 per cent step. Also improvements in edible food from 25 per cent step.

The costs outlined in Integrated Assessment Baseline and Scenarios are similar to those identified in the media release issued by the project in September (See

At the top end of estimates, under water quality scenario one, a potential was identified for multi-billion dollar regional gross domestic product (GDP) reductions over coming decades in discounted present day terms. That is based on an annual regional GDP reduction of $630 million (equivalent to about three per cent of regional GDP) in present day terms.

“What the confirmed estimates clearly show is that costs are potentially very substantial over time and illustrate the complexity of the issues Health Rivers/Wai Ora is grappling with. The figures take no account of river health protection measures being phased in over time, as is expected will happen,” Mr Wasley said.

“The good news in the second modelling report is that making a start – and making some substantive progress – can be done relatively cheaply. The second modelling report sets out the cost of progressive steps towards scenario one, which is considered to meet the Vision and Strategy. Getting 10 per cent of the way might reduce the actual profits of land use by around three per cent a year, while getting a quarter of the way there would cost around seven per cent.”

Beyond this, with the cheaper options already used up, further improvements become more expensive, Mr Wasley said. Getting half way to scenario one could reduce annual profits by a quarter, and getting three quarters of the way there could reduce them by half.

“The CSG’s challenge now is to sift through all this evidence and advice, along with the input we’ve had from the public, to come up with a sound, science-based recommendation for a regional plan change in the new year.”

The two new reports and an earlier economic modelling report are available online at: