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Talking about restoring Lake Hayes – a model for the district?

Photo credit:  Destination Queenstown  Lake Hayes in Autumn

Otago Regional Council (ORC) Dunstan ward candidates Alexa Forbes and Richard Bowman have worked together to provide you with this look at the Lake Hayes restoration plan.  The pair have separate interests in the project – Richard is a long standing member of Friends of Lake Hayes and has a background in environmental management, and Alexa is chair of Infrastructure and councillor at Queenstown Lakes District Council – but both want to be elected to the regional council to drive exactly the sort of work that is happening at Lake Hayes across other catchments and issues in the district.  They each attended separate ORC drop-in sessions. 

ORC people set up their presentations covering 8 intervention options for the restoration of Lake Hayes at the Lake Hayes pavilion on August 13, ahead of a public submission process. So far, so business as usual.  What was different this time was that people attending were offered explanation and advice on the options – independent advice.  Those on hand to help included water scientist Dr Max Gibbs from NIWA, and independent lake scientist Dr Marc Schallenberg from Otago University.  ORC staff were also there to explain process and their views.  The independent scientists were happy to explain how each option might work and what their personal opinions were – freely offering their own recommendations when asked. So participants were able to walk away with a pretty good understanding of how to weigh up the interventions, what the costs and benefits where likely to be, and how they might make an informed submission.

After 20 minutes with NIWA Dr Gibbs, Alexa had a rough working idea of what was going wrong in Lake Hayes.

Lake Hayes phosphate cycle

This phosphorous/phosphate cycle is likely the major cause of the lake becoming eutrophic.  Concerns about the health of Lake Hayes have existed for half a century or more with the first algal bloom noted in 1969. An Otago Regional Council and Queenstown Lakes District Council management strategy  (1995) described the lake as eutrophic characterised as ‘anoxic, poor water clarity, frequent algal scums, fish deaths and insect pests’.

In around 2006 a new species of algae (Ceratium) appeared in the lake and this has caused much longer lasting blooms which resulted in an intense stratification of the lake. This involved a warm, algae rich layer at the surface down to a depth of 5-8 m deep. Beneath this was a dark, cooler deoxygenated, cooler layer down to the lake floor. This layering severely disrupted the habitat of brown trout and the population has declined since these events began. The blooms also gave the lake surface an unattractive brown hue and may have caused ‘hay fever-like’ symptoms to affect long distance swimmers. These blooms were the catalyst for starting the Friends of Lake Hayes which has been working for over 10 years now to find solutions to the water quality issues in the lake. In the last two years new water quality issues relating to Cyanobacteria algae blooms and E coli bacteria have caused the lake to be closed for water contact recreation for extended periods

Over the last two decades some, but too few, actions from the 1995 plan have been implemented (such as moving from sceptic tanks to reticulated sewerage) and the lake may have slowly begun to heal itself according to Dr Schallenberg.  However, there’s much that can be done and that needs to be done to protect the recreational and habitat values of the lake.  A monitoring buoy is finally in place and the information coming through will soon be on the ORC website for everyone to access.

Friends of Lake Hayes have been agitating for years to get that plan implemented, and to get monitoring in place.  Things have picked up quite a lot since Mayor Boult was elected and the agitation subsequently moving up a few political levels.

The consultation provided on the 13th was collaborative, inclusive and frankly, how consultation should and can be – bringing together the authority, the experts, the community groups, interested parties and general public. This is how we get evidence backed decision-making and informed public input.

The experts and council are back again on September 3 for those who missed it yesterday.  Note: that day is also closing day for submissions – they close at midnight September 3 so you’ll need to move quickly if you want to base your submission on what you learn at the consultation sessions.

Do some preparation work and learn more about the proposals here. The technical methods up for consideration are here . There’s a consultant’s overview report here. Technical methods such as flushing with augmented water, or chemically trapping the phosphates or withdrawing nutrient rich sediment are all explained in the technical report on the same page.  The consultation is asking people to decide which combination of technical methods are considered best.

For Alexa, option one, to monitor and evaluate, is the very least that should be done and it must be ongoing – the new business as usual.  Options two, three, four, five and six have a range of associated issues with high risks for low benefit in her opinion. Option seven, which includes withdrawing the nutrient rich water, seems the right balance, particularly if you can capture and reuse the phosphorous coming out of the lake and ensure adequate prevention of more phosphates entering the lake system.  She agrees with Richard that there is much more to be done on reducing the nutrient load entering the lake through soil.  Much of this work will rest with Queenstown Lakes District Council, advised by, and partnered with ORC and people who are observing the lake on a daily basis – Friends of Lake Hayes.

Richard is of the view that the main focus of restoration of Lake Hayes should be on reducing levels the phosphate, nitrate and bacteria entering the lake through an integrated catchment management programme. This could include riparian management (planting of banks and shading) in Mill Creek and its tributaries as well as building or re-instating wetlands to capture sediment and nutrients. Augmenting the flow of water into the lake using cool, clean surplus water from the Arrow Irrigation Scheme to help flush out resident nutrients from the lake is also a promising tool. Having a continuous monitoring buoy in the lake at last means that we can get a much better understanding of the algae blooms in the lake and what drives them. This information can be used to enable computer modelling to test the 8 various restoration strategies before implementing them and to monitor the performance of any methods that are tried. Current ecological studies of the food web in the lake may also provide new tools to help regulate the algae blooms when they are completed.

There are many living near the lake who also think that creating a larger outlet for the lake should be part of any solution. This was not specifically addressed in this consultation but is worth bringing into the discussion and may require including another agency, New Zealand Transport Agency, to implement.  It’s believed that widening the outlet would allow the lake to flush more easily in times of heavy rain and would have the added benefit of preventing some of the flooding that could allow unnecessary washing of phosphate laden soil particles into the lake.

Both Richard and Alexa see the drop-in sessions as a major step forward in ORC consultation.  Allowing ORC staff and their technical experts to engage directly with the affected community to find solution together seems the best use of everyone’s time and reources. Assuming this community collaboration model being tried at Lake Hayes works well then it can also be applied in other parts of the region to address a range of environmental problems.

The session also provided space for people who owned land in the area to discuss their ideas and concerns with each other, technical experts and scientists.  One couple were looking for information on the Friends of Lake Hayes project  to re-establish wetlands in the flood zone at the north end of the lake. They were keen to contribute land and effort to that project. The session also informed other risks to the catchment – such as the felling of Coronet Forest which is planned as part of wilding pine management.  One of the scientists pointed out the sediment that could be released during that harvest could be devastating for the Lake. This will need to be mitigated through comprehensive soil management measures. This illustrated how a holistic view of all systems is needed when decisions are taken.   Imagine how our waterways would be if such a consultative, inclusive approach was taken for every single catchment?

Richard and Alexa agree that this is what they want to see much more of from ORC. A collective, holistic approach where people can get together, understand the issue, then the options, then debate and discuss before putting forward their own submission into the process.  This is healthy democracy in action.

Contact:  Richard Bowman –, Alexa Forbes –

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