12 Jun 2015

Wellington Council urged to tackle flooding problem

3:35 pm on 12 June 2015

A Wellington man who moved his business after it was repeatedly flooded is urging the council to address the city's flooding issue once and for all.

Streetsoundz owner Krisna Magan (left) estimates the flooding has caused more than $100,000 in damage.

Krishna Magan moved his audio business after it was flooded for a third time in May. Photo: RNZ / Alexander Robertson

A draft report commissioned by the city's water network contains two options for upgrading the central city's drainage systems.

The cheaper option is a new pump station, and the more expensive a large culvert the length of Kent and Cambridge Terraces from the Basin Reserve.

Krishna Magan moved his car audio business, StreetSounds, away from the Basin Reserve after it flooded for a third time in May.

He said he wanted the council to follow through on one of those solutions.

"It's put us in a really awkward position. We've had to move out. We own the building; we're still paying the rates, near $20,000 a year," he said.

"As far as I know, the problem isn't being looked at and it hasn't been sorted."

According to a copy of the draft report, obtained by Radio New Zealand News, upgrading Wellington's water network to better cope with flooding could cost between $24 and $45 million.

Commuters wait in vain for news at Wellington Railway Station.

The Wellington Railway Station was temporarily closed by flooding in May. Photo: RNZ / Shannon Gillies

The Newtown Catchment Stormwater Upgrade Study was instigated after severe flooding in 2013, during which fire crews had to pump water out of some buildings near the Basin Reserve.

The same area was again flooded during storms in April and May this year.

The draft report, carried out by the construction and engineering firm Jacobs, looked at six options to upgrade the water network to reduce flooding risk.

It then focussed on the two most viable options.

The first is building a pump station on Kent Terrace near Courtenay Place. That comes with a $24.1 million price tag.

The second, which the report calls the most effective, is a $44.8 million culvert running the length of Kent and Cambridge Terraces.

One of the flooded rooms at Duckworth Lewis Accomodation Basin Reserve, Wellington where 30 tenants were evacuated from the building.

One of the flooded rooms at Duckworth Lewis Accommodation Basin Reserve, where 30 tenants had to be evacuated from in April. Photo: RNZ / Alexander Robertson

It said that the culvert also best addressed the existing undersized network near the Basin Reserve.

While the pump station would provide much the same result in terms of mitigating floods in outlying suburbs, it would not have as much impact around the Basin, the report claimed.

Firefighters pumping out a flooded carpark in Newtown, Wellington.

Wellington firefighters have previously had to pump water from flooded buildings, including this carpark in Newton. Photo: RNZ / Alexander Robertson

The study noted that while the culvert would cost nearly twice as much as a new pump station, the cost of the latter could go up based on the design details and ongoing maintenance costs.

It also explored the option of daylighting - either completely or partially exposing the waterways from the Basin Reserve to the ocean.

It discussed shifting Kent Terrace towards the centre of the road, and opening up the Waitangi Stream alongside.

"Kent Terrace could then become a green park with walkways, bridges, trees, hospitality... allowing the community to connect with Waitangi Stream and the adjacent area."

"Planting adjacent to the stream would enhance aquatic life. In addition, this park could become a valuable secondary flowpath for network overflows."

It said while daylighting could be a feasible option, no specific modelling into the idea had been done.