Powerhouse Civil

Dumping. Another slip. The gravel below the high tide line.
Dumping. Another slip. The gravel below the high tide line.

I was looking for erosion sites when I saw Powerhouse Civil actually dumping material into Tamaki Estuary here. I will let Auckland Council know tomorrow.

UPDATE: (2 Weeks later) Rowan from By-Laws called me and is referring it to a pollution dept.

Zinc

Zinc contamination in sediment
Zinc contamination in sediment

I didn’t really get how zinc from galvanised roofs could be poisoning the estuary until I made this map. I found a presentation by Marcus Cameron which suggests that sites the source (the head of the estuary) are trending up (more zinc). At the same stormwater conference Judy Anne Ansen showed a pie chart on Industrial (Mt Wellington) zinc sources with about 80% attributed to roofs.

Marine report card for Tamaki is here:
http://stateofauckland.aucklandcouncil.govt.nz/marine-report-card/tamaki-estuary-reporting-area/

More in depth articles on the zinc problem here:
http://www.aucklandcouncil.govt.nz/EN/planspoliciesprojects/reports/technicalpublications/Pages/technicalreports2008.aspx
This one is the best SOURCE CONTROL OR TRADITIONAL BMPS? AN ASSESSMENT OF BENEFITS AND COSTS IN AUCKLAND CITY

My Questions/ Answered:

  1. How bad is zinc for the environment & what is it hurting? / 50% of organisms are expected to be affected
  2. Can we remove it without moving the mud?
  3. Is painting industrial roofs clearly the most effective fix? / Yes, tho storm water ponds can be great and they have other benefits