Hikuwai peaks at nearly 9m

Motorists coming into the city yesterday morning had to drive to the conditions as hours of consistent rainfall led to surface flooding and debris washing up over State Highway 35 at Makorori. Picture by Liam Clayton

More rain, more flooding, more slips and road damage and more misery for Gisborne-East Coast residents suffering from one of the wettest years in recent memory.

The weekend brought another deluge, courtesy of a turbulent and slow-moving weather system that parked itself off the coast, dumping on an already saturated district and adding to the fix-it list.

The district council had to open the sewage discharge valves again, to release the pressure in the stormwater system, and has warned against activities in the Turanganui river and city beaches, and the taking of seafood.

There is surface flooding everywhere. A slip near Otoko has partially blocked State Highway 2 through the Waioeka Gorge, and more road damage has been added to the list accumulated through cyclones Hale and Gabrielle.

As of yesterday, 13 local roads remain closed, while 43 are listed with weather damage.

After another two days of steady rain, the region’s rivers are flood-swollen again — the Hikuwai River at Tolaga Bay peaked at nearly 8.9 metres.

Inland from Gisborne the Waikohu River hit a peak of 7.9m, the Wharekopae River 6.2m and the Waipaoa rose to 5.6m.

At the East Cape end of the district the past few days have seen rainfall totals climbing towards the 200mm mark, while near Gisborne. the gauge at Pouawa recorded over 113mm in one 24 hour period.

The soil everywhere has turned to slop, and during the lightning storm trees came down, with one farmer discovering a large gum tree had smashed the front of a three-bay shed.

With the latest downpour, Gisborne has had approaching double its normal June rainfall, and the whole district has had more than twice its normal full year’s dose of rain.

Yesterday an orange rain warning was still in place, with MetService forecasting a further 30 to 50mm on top of what had already fallen, and  saying further thunderstorms were possible.

MetService meteorologist Dan Corrigan says unfortunately another system is likely to bring more of the wet stuff on Thursday and Friday — a prolonged period of wet weather to northern and eastern parts of the North Island especially the Coromandel Peninsula, Bay of Plenty and Gisborne.

“The accumulation of rain over several days in these already sodden areas could cause surface flooding and activate slips regardless of whether warning amounts of rain occur.

“There is moderate confidence rainfall amounts will reach warning criteria for Tairawhiti/Gisborne from Wednesday to Saturday.”

Sewage discharge valves opened to cope with ‘large amounts of rainwater’

Heavy rain in the city on Saturday night forced the council to open the emergency sewage discharge valves, with raw wastewater still flowing into the city river system yesterday.

Some parts of the city received nearly 100mm of rain in 24 hours at the weekend.

“Our wastewater system has been flooded with large amounts of rainwater draining from residential properties into the sewer, causing some pump stations to be put under pressure,” the Gisborne District council said online.

“To relieve this pressure and prevent sewage from overflowing back into homes and on to roads, causing a significant potential health risk on properties in the city, we opened the emergency sewer valve at Gladstone Road Bridge into the Turanganui River on Saturday night (June 17).

“The discharge is highly diluted with rainwater, but there’s still a risk to health.”

Temporary warning signs are installed along the affected rivers and beaches.

“We advise no fishing, gathering shellfish or water activities in rivers and beaches until at least five days after the valve is closed and warning signs are removed.

“We seriously consider all options before we open the overflow valves and discharge wastewater into our city’s rivers,” the council said.

“It’s only done when it’s absolutely necessary and only in the areas with issues in the network. The decision to open the valves is left until the absolute last minute when there’s no other option.

“We will notify the public when the discharge has stopped.”