Two freshwater lobby groups based in Wanaka are up in arms about the Queenstown Lakes District Council’s proposal to defer a $6 million stormwater upgrade budget until 2030.

Friends of Bullock Creek and the Guardians of Lake Wanaka are calling for the council to do the Stone St stormwater project next year, as originally planned, and to increase the budget to $10 million.

Their submissions to the council’s draft annual plan claim the Roy’s Bay stormwater catchment has been mismanaged for several years, leaving the spring-fed Bullock Creek and Lake Wanaka vulnerable to ongoing pollution and damage.

Investing now would prevent another seven years of degradation, and the extra $4 million would ensure the work was done in an expedient and robust manner, the Friends say.

Wanaka’s Stone St stormwater budget is among $106.4 million worth of projects to be deferred so the council can settle historic leaky homes claims, address climate change, cope with ongoing fall out from the Covid pandemic and increase staff wages.

The decision to defer projects had been made during ‘‘very difficult economic conditions’’ to reduce next year’s capital expenditure from $293 million to $202 million, the draft annual plan states.

However, the budget is still $34 million more than proposed for year three of the 10-year plan that was approved in 2021, which will result in an average annual rate increase of 13.6%.

But the Friends contend the council is as liable for Bullock Creek contamination as it is for leaky homes.

‘‘The reality of this deferral is that it is effectively trading off past generation’s financial liability against . . .at least another seven years of stormwater contamination of Roy’s Bay and the creeks within the catchment,’’ Friends of Bullock Creek committee member Nancy Latham said in the submission.

The Friends contend groomed slopes for urban development have removed the ability of the environment to filter and treat contaminated stormwater before it reaches freshwater bodies.

The Friends have reminded the council it was was issued an abatement notice by the Otago Regional Council for contaminated water that entered the Bullock Creek and its wetlands.

The Guardians of Lake Wanaka submission by chairman Don Robertson said a proposed pathway for stormwater runoff from the Alpha Series development would go into a sump in an area of shallow groundwater, a few metres away from the springs that feed Bullock Creek.

‘‘This means that all or most of the stormwater . . . will inevitably flow into Bullock Creek and into the lake at Roy’s Bay,’’ Mr Robertson said.

Stormwater would be expected to include a range of contaminants, including heavy metals, nutrients, herbicides and bacteria, he said.

The groups have been raising concerns about Bullock Creek since at least 2015.

The council has not started working ona proposed diversion through the Wanaka Showgrounds. That was supposed to begin last September.

The council’s annual plan hearing has been scheduled for May 23, with adoption scheduled on June 29.