Hospital reservoir needs repairs

Wellington Hospital is confident its 2.5 million-litre reservoir will stand up to a significant earthquake, despite the decades-old tank nearing the end of its anticipated lifespan.

A detailed seismic assessment from 2017, released under the Official Information Act, has shown that while repairs were made 10 years ago to extend the reservoir’s life, that time is now up.

One of the main concerns raised in the report, which had yet to be addressed, was that the concrete floor slab was not structurally fixed to the foundation, but rather ‘‘locked into place by geometry’’.

However, Capital & Coast District Health Board (CCDHB) corporate services general manager Thomas Davis said work was set to get under way in the new year.

‘‘Planning work scheduled for early 2019 – as well as progress on the Prince of Wales reservoir – will likely inform our further planning around water resilience and investment in our reservoir.’’

The 2008 report forecast the reservoir’s functional life to end between 2018 and 2023, giving the health board a window of opportunity to work on suggested repairs and other life-extending work, including seismic shut-off valves. Davis said that new resilient pipe work connections and valving, designed to meet a 1:500-year earthquake resilience objective, was being installed as part of the hospital’s current programme of works.

‘‘Further investment in strengthening in the event of a 1:2500-year event may be considered at a later date.’’

The questions raised about the reservoir’s future come in the wake of concerns revealed by Stuff, about the state of the hospital’s generators, which are supposed to kick in if mains power is out. One expert gave the generators a one-in-four chance of not running at all but CCDHB said its generators would work.

In August, the health board was also forced to reveal its response plan for what would happen at the hospital if such a magnitude-7.4 quake were to strike.

Discussed in that plan was ‘‘extremely limited’’ water supply in the first three weeks postquake. The plan said it would be six months before reliable, treated water was fully restored.

The hospital’s expected water woes mean that, immediately after a big quake, water would not be used for hand washing.

When it was crucial, the ‘‘two bowl’’ method had to be used – one bowl for washing and another for rinsing, with water only being changed when necessary, and only if there was enough of it.

‘‘Further investment in strengthening in the event of a 1:2500-year event may be considered.’’ CCDHB corporate services GM Thomas Davis