"I would be surprised if it is in excess of $1.5m," Routhan said. "That to me is affordable. I know it's nice to have the Rolls Royce but the Rolls Royce is a dream.
"My preference is to build a new pond, put the sewage into the new pond, clear the other two out, fix the breach ... restore the systems we've got. The river protection will be a big cost but it's half done now (so) we've only got to finish it."
River engineer Mark Healey told the council a stopbank of at least 4m high would be needed on top of the existing height to protect the oxidation ponds, and said it would be important to maintain all stopbanks upstream of the current ponds.
However, Mayor Bruce Smith said regardless if they went with a treatment plant or oxidation ponds, protection work would still be needed.
"We have an obligation to the people who live opposite the 55kph corner and they've been sitting there for some time and every time it rains they're wondering if the Top 10 (Holiday Park) is going to be washed away. The school's there ... we have an obligation to do something about it, so no matter what happens with the ponds that's got to be protected," Mr Smith said.
The logic of combining the two was "quite compelling".
He asked for direction from councillors: "The issue is, do we go with ponds or do we go with a plant?"
Councillor Helen Lash, the Franz Josef community development officer, said she was concerned about long-term capacity. Up to 5000 people can be in Franz Josef on any given night in the peak season, and in five years that could climb to 7000.
She also questioned what consenting issues they might face under the Resource Management Act for ponds now and in the future.
Representatives of South Westland iwi Makaawhio were also present at the meeting and stated that they would not support the development of unlined sewerage ponds. They also did not support any untreated sewage going into the river or soaking pits that would go to the riverbed.
Tumuaki (manager) Susan Wallace said initially they had supported the mechanical plant because it was "future proof".
Cr Jane Neale was alone in voting in favour of the treatment plant, which would cost about $150,000 a year to run once commissioned, for the same reason.
However, Routhan said the cost for ratepayers was just too high, and Havill agreed: "I believe ponds are the way to go and everything is airy fairy unless we get a contractor to come in, give us a price to do the job, then we're on firm ground. If it's not acceptable then we have to look at other options."
The council was advised that both options could be under way by June next year, which would be acceptable to the timeframe set by the West Coast Regional Council, which has agreed to temporarily halt Environment Court proceedings over the current non-compliant state of the ponds.
- Hokitika Guardian