Email An independent reviewer will be asked to investigate whether the backflow of sewage into Palmerston North's Escort Gr during the weekend's flooding could have been prevented. City council water and waste services manager Rob Green said the storm had created a series of problems for the systems, and he was keen to see if an outsider could identify ways it could have been handled better.
The cleanup in the street is continuing, with two flooded and contaminated cars towed away, and council crews helping residents decontaminate their properties. The sewage-laden floodwater did not go through any houses, but it went underneath some. Resident Denise Jarden said a couple of inches of smelly sludge was left under her house, and she did not envy the worker who was heading under the floor to clean up and disinfect.
Jarden said while the council crews working in the street had been heroes for residents, she was still looking for someone to take responsibility for what happened and make sure residents could replace damaged gear and belongings, such as her son's motorbike gear.
Green said the problem began on Saturday morning after torrential rain overloaded stormwater systems. The surplus wastewater arriving at the Totara Rd treatment plant which could not be coped with was spilled directly into the Manawatu River from Saturday lunchtime for about 24 hours. The emergency discharge had been reported to Horizons Regional Council. Green said problems developed quickly during the massive storm. Stormwater had started ponding in low-lying Escort Gr, unable to drain into the stormwater retention area at the Totara Rd Pony Club, which was full, which in turn could not be discharged to the Mangaone Stream while it was running so high.
Infiltration of the sewerage network sent huge volumes of wastewater to the treatment plant, which could not cope with the inflow. The gates closed to control the amount going in, and a valve was manually adjusted to release the excess directly to the river. Some time during that process, wastewater had backed up and the pressure popped at least one manhole cover.
