Seeking more (uncontaminated) water

by Jim Mikoz
There are two major issues to be dealt with if drilling for freshwater succeeds in finding a new aquifer under Wellington Harbour.

First: a new water treatment plant will have to be built before the water can be distributed into the Wellington water supply. That will cost a bit and a site will have to be found.

We already know, with the closure of the Buick Street water fountain, that water in the aquifer is contaminated. Has anyone tested the water at the Moore Wilson water fountain?

Unfortunately the ground water will always be contaminated because the springs under the Silverstream rubbish tip were never sealed, although Mayor Dowse asked the Council and Government for money to seal the tip after the road was built into the tip. This request was dismissed as the council said they had already spent five million dollars building the road. I received this information when I worked on the machinery building the road.

Before the new tip was built over the old tip and a resource consent was granted, chemicals and human waste solids were buried in holes in the tip – they would take only three days to travel into the Hutt River after heavy rain.

Research was carried out by DOC to determine what killed all aquatic life in the Hutt River. The dead fish and eels were collected by the council and DOC and were disposed of. They traced the kill to the chemicals buried in the Silverstream tip.

Stokes Valley people take their dogs for a swim upstream of the tip as the algae on the rocks downstream becomes poisonous in summer – but not above the tip.

And there’s another problem where the water enters the aquifer between Stokes Valley and the Taita Rock on the other side of the valley. The Regional Council have filled in the deep holes that were once there and made a series of rapids, thereby reducing the head of water above the aquifer and reducing the quantity of water entering the aquifer. This has reduced the flushing effect of the water traveling through the aquifer – the Wellington Harbour submarine fresh water springs have lost a massive amount of pressure since 1999 when I recorded the water coming off the spring and compared it with photos of the springs taken in 2015.

The Radio NZ report about drilling for water also mentions tapping into the aquifer in Porirua. The aquifer shingles extend into Porirua as millions of years ago there was a glacier that went from the Hutt Valley to Porirua. The large rocks found in the moraine from the glacier were extracted out of the John Ray Quarry on the Haywards and are now used as groynes in the Hutt River behind Taita.

Those building the Transmission Gully bridges will be able to tell you at what depth they found the aquifer water as some of their bridge piles have penetrated the aquifer. I hope they seal it off better than those who built the QueensGate carpark.

The other issue that will have to be addressed is that CentrePort have indicated they want to deepen and widen the shipping channels in the harbour narrows at the Falcon Shoals. That would penetrate the aquaclude and release ground water at a pressure and in quantities unknown. If they went ahead with dredging, this could reduce any water found to a trickle.

The Regional Council have already discovered how fragile the aquaclude is at the nine metre deep Falcon Shoals where the fast ferries blasted the seabed with their jet units as they passed over the area. I wrote to the council expressing concerns at the time, as after they passed over the area, you could see air bubbles coming to the surface for ages.

It was not until I drove into the wake of the fast ferries off the south coast and took photos from the image on my sounder that we could prove how the fast ferries blasted the seabed in 42 metres of water. This explained why the blue cod left the Sounds, as on average the water is only 20 metres deep and the mud lifted then smothered the cod’s food sources.

The ferries were taken out of service three months after I took the photos.

Jim Mikoz is president of the Wellington Recreational Marine Fishers Association.

 

6 comments:

  1. Anabel, 14. May 2017, 11:35

    After months of investigations, Wellington Water will not tell us the source of the aquifer contamination. Or what investigations were undertaken since February, from which they have provided no results.

     
  2. TrevorH, 14. May 2017, 14:45

    This is a really interesting and informative article, thank you. It deserves wider publication.

     
  3. Andy Mellon, 14. May 2017, 19:08

    Great article. Very interesting. Definitely seems like a lack of transparency and communication with respect to our region-wide water supplies at the moment.

     
  4. Mark Shanks, 15. May 2017, 7:06

    Thanks Jim. Practical knowledge and genuine information through observation is a rare commodity these days in a world of ex-spurts. WW haven’t told us anything because they don’t know, yet it’s very convenient for them to blame the November earthquake.

     
  5. Geoff Henry, 16. May 2017, 22:06

    Our problem has always been, and continues to be, that our governance bodies pay firms of contracting engineers massive sums for reports which say what their paymaster wants them to say. The engineers don’t have the practical knowledge of what’s actually happening in the water. Jim’s views are based on a long history of practical observation. Bugger the academics…. lets get back to practical realities!

     
  6. D Seitz, 17. May 2017, 17:36

    Thanks for publishing this. The author has a strong reputation on various environment issues and seems both willing and able to demonstrate his assertions. I rarely see them challenged. There is something wrong with a bureaucracy which apparently ignores or at very least refuses to engage with people with practical experience and sound knowledge based on observation and records.

     

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