Power giant Contact is caught up in a gooey mess at Cromwell in Central Otago.
Following a protest, the near-$6b company acknowledges it could be doing more to work with interest groups over the management of Lake Dunstan, the huge body of water formed by the Clyde Dam, 23km upstream. It has also called in external experts to reassess its waterway management plan.
Sludge washed from the Kawarau River (fed by the Shotover) is mounting up to the Cromwell foreshore, silt islands have formed, logs litter waterways and the invasive plant pest lagarosiphon must be cleared regularly from the lake.
In a region famous for pristine rivers and lakes, the sludgy mess is preventing use of the foreshore for swimming and boating.
The Clutha River was dammed at Clyde as part of the Think Big programme of the late 1970s and was opened in 1992.
Growing frustration with the management of Lake Dunstan flared at the weekend with a protest timed to coincide with the high profile opening of a cycle trail that runs along the western side of the Clutha River.
Protest group Save Our Lake Dunstan (Sold) says Contact has responsibilities to operate the dam but also act as good corporate citizen.,
When the dam and formation of the lake was planned, commitments were made by the government at the time and the operators of the hydro dam that Cromwell would have and be able to use Lake Dunstan for recreation, said a group spokesman, Brendon Urlich.
"We now understand that with the slowing of the flow of the river that sediment and the deposit of silt is inevitable (this was never explained at the time). We are not asking for remediation of the silt working its way down the river to Cromwell, we are simply asking that Contact Energy maintain key recreational parts of the lake such as the around Old Cromwell ."
Urlich has a property above the foreshore and says it is a water quality issue.
"We watch tourists attempt to swim in the area and quickly exit when they realise how terrible the area is. It is embarrassing. We feel that Contact Energy is putting profits before people — their neighbours deserve better," said Urlich.
Boyd Brinsdon, head of hydro generation for Contact Energy, said the company undertook
a range of activities which include: the removal of driftwood in the Kawarau Arm, monitoring the lake bed for sediment build-up, providing access for water takes, installing and maintaining safety signage, monitoring archaeological sites, and managing the bed levels of the Bannockburn and Lowburn inlets.
"We are committed to managing the effects of our hydro-generation activities on the landscape and visual amenity of the Kawarau Arm. We acknowledge that we can do more and we will work through this as part of the consultation under way at the moment."
He said Contact's obligations were around mitigating the adverse effects of generation activities on Lake Dunstan (and the wider Clutha catchment) in line with the conditions of resource consents granted by the Otago Regional Council.
"We take these consent conditions seriously, and this includes preparing a landscape and Visual Amenity Management Plan setting out how we will manage the effects of our hydro-generation activities on the bed of the Kawarau Arm of Lake Dunstan."
As part of this process, the company consults with the Central Otago District Council (CODC) and Otago Regional Council (ORC) and sets out a programme of activity.
"We are under way with reassessing the plan for the second time since it was created back in 2009. We've engaged external experts for this reassessment and have provided the draft plan to the CODC and ORC for consultation.
The plan would be up for discussion and debate. It is involved in consultation with the community through the councils and also the Lake Dunstan Charitable Trust and others.
"There is more community engagement with the plan and consent obligations than when we last reassessed the plan in 2014, and we welcome this."
While it has not met Sold, Brinsdon said he was keen to do so.
"We would welcome the opportunity to sit down and explain our perspective and better understand their concerns."
Sold's Urlich said individual members who had been in touch with Contact had received just generalised statements about corporate responsibility and the group was open to meet the company.
"We ask that Contact comes with a plan for action. We also ask that Contact has open forums and communication to the public to hear the voices of their neighbours."
He said the communication to date was via the councils "which filter and numb the real frustrations and anger of the public".
The people of Cromwell were "in the dark "and this must change.
Central Otago District mayor Tim Cadogan said the council "does not have a set view" on silting, the result of about one million cubic metres of mud being washed into Lake Dunstan.
''The amount of silt that comes down each year apparently equates to the amount of concrete in the Clyde Dam so trying to stop it is pretty much like trying to hold the tide back. It is an unfortunate reality that the beautiful arm of the lake, created by the building of the dam, is going to be taken away by the consequences of the building of the dam and eventually become more like a braided river.''
The cost of dredging the silt out would be ''phenomenal'' given the amount that comes down and then there was the very real question of where millions of tonnes of wet silt would be put.
''Also I'm aware that Contact Energy is required to develop a landscape and visual amenity plan for the bed of the Kawarau Arm to address the adverse effects associated with its activities.''
Cadogan said the council was a party to the development of this plan.