No single remedy exists for preventing overflow from the Pleasant Point sewer system into the Opihi River, according to a Timaru District Council report.
On June 27, the ponds were filled to capacity through high groundwater levels, so 600 cubic metres of treated oxidation pond effluent was discharged into the Opihi.
The ongoing problem has been monitored and will continue to be so, according to council water services operations engineer Judy Blakemore.
Action by the council so far included metering the outlet to the Pleasant Point pump station and ponds themselves.
Also, smoke-testing private sewer plumbing in the area of State Highway 8 and west of Tengawai Rd, Pleasant Point, was completed on July 16.
"No direct stormwater entry to the sewer was found, although there are several low gully traps."
Plumbers had been commissioned to rehabilitate some manholes. An assessment had been completed and site work was scheduled to start in early August.
Proposed action to be heard at today's community development committee meeting includes continuing the close monitoring and analysis of the water table level and flows, extending the scope and scale of smoke testing, manhole repairs and pipe CCTV work, and to prepare an action plan and budget as a result of CCTV work.
"There is not one item that will provide a remedy to the over-full ponds and the only realistic option was used in order to avoid creating a much large issue. The net effect on the Opihi River was minimal," Blakemore said.
- The Timaru Herald