The Otago Regional Council has reviewed the "many" wastewater discharge consent applications it has processed in the past 10 years, identifying 20 significant consents totalling $232 million, the largest being the Dunedin City Council's $120 million Tahuna waste treatment plant and outfall.
Other local body consents totalled about $59 million and industry consents $38 million.
Council resource management director Selva Selvarajah said in a report considered by the regulatory committee yesterday the council had been successful in improving discharges due to policy direction in the water plan, applicants co-operation, the high technical knowledge of treatment systems and an "outcome and principal-based approach" by council staff.
"It has been a marathon effort."
Chief executive Graeme Martin said there had been "tough times" but he hoped the council's collaborative, effects-based approach had been "consistent and fair" to achieve the outcomes which the council should be "proud of".
Chairman Stephen Woodhead agreed it had not "plain sailing", with some applicants historically receiving "shoddy advice" and as a result having systems that did not deliver.
However, "we had to hold the line" and as a result the decrease in ecoli levels in discharges was "absolutely staggering", he said.
Cr Duncan Butcher said in the early days some sewerage systems were "diabolical", allowing raw sewage to flow into the Clutha River.
"It took us a long time for district councils to agree, given the capital costs."
The regional council's approach of giving local bodies a transition period while investigating and implementing new systems worked, he said.
Now, the council had to look at how its new water quality plans would affect those consents.
Cr Louise Croot said it had taken much time and staff work to tighten up the conditions of consents, especially in the case of the skifield consents.
