Otago Fish & Game chief executive Ian Hadland said contaminated stormwater from the neighbouring Alpha Series subdivision stormwater holding pond has been discharging into Bullock creek for at least five years.
The stormwater management system was ‘‘found not to be fit for purpose’’, he said.
In the past week, Otago Fish & Game and the Queenstown Lakes District Council have reached an agreement for an easement across the Otago Fish & Game private land to enable the transfer of stormwater.
‘‘Urban development that causes silt to enter fish-spawning grounds is never acceptable ... Fish & Game is pleased the council has looked at the wider Bullock Creek catchment and its headwaters in the development of their stormwater management proposal,’’ Mr Hadland said.
Alpha Series developer Allan Dippie did not believe the flooding of Bullock Creek and the wetlands was a result of his subdivision development.
‘‘Any development above Bullock Creek must not add additional stormwater flows to this natural pre-development flow ... New development must retain or dispose of all stormwater that is generated over the natural pre-development flow.
‘‘This is what each stage of the Alpha Ridge subdivision does and this is why each stage has been consented and approved by council,’’ Mr Dippie said.
Mr Hadland agreed the catchment size was largely unchanged and rainwater still fell as it usually did.
However, ‘‘the developer fails to acknowledge the change to the discharge of that water following subdivision into hard surfaces — it travels to the receiving environment much quicker and is typically of poorer quality,’’ Mr Hadland said.
Friends of Bullock Creek secretary Roger Gardiner said the community group had been informed of mitigation plans for the stormwater issues, ‘‘but we are neither supporting nor opposing the proposed plans as we do not have the expertise to assess the environmental or social implications of such plans’’.
‘‘We believe wider community engagement will be required before implementation,’’ he said.
Wanaka ward councillor Niamh Shaw said an urgent solution to address stormwater runoff through Bullock Creek was ‘‘clearly needed’’ and the negotiations with Fish & Game to secure an easement agreement was just one facet of that.
‘‘Council has prepared a preliminary system design, which should be approved early next week, after which we will engage with interested and affected parties.’’
She said many residents had also contacted her about how council planned to avoid similar stormwater issues in the future.
‘‘Council’s engineering department was working on a catchment management plan to understand areas prone to flooding — now and in a climate-changed future — which will enable the strategy and performance team to ensure better stormwater outcomes.’’
