Subscribe to RSSAnother High Tide This Week
Road users are being reminded that there is a risk of flooding on a section of the Northwestern Motorway because of unusually high tides in the Waitemata Harbour later this week.
High tides of up to 3.4m – about 0.4 metres higher than normal – will occur from Wednesday to next Monday.. Tides like this occur in Auckland every six to seven years.
The NZTA says the area on the Northwestern Motorway most likely to be affected is the causeway across the Waitemata harbour between the Patiki Road Interchange and the Rosebank Road bridges.
The cycleway beside the highway will be flooded, and the NZTA is advising cyclists to try to avoid using it 90 minutes either side of the high tide mark.
‘It is unlikely the motorway itself will be affected, unless weather conditions like strong winds have an impact on the tides,” said the NZTA’s State Highways manager for Auckland, Tommy Parker. “There is a traffic management plan to re-direct traffic away from the causeway if there is flooding.”
The NZTA is planning to raise the causeway by 1.5 metres and increase the width of the motorway to provide extra lanes as part of the Western Ring Route development.
Related Posts
- Unusual High Tides Threaten Auckland Motorway
- Auckland Cyclists Warned About High Tides!
- Next Week’s Motorway Closures
- Next Week’s Motorway Closures
- Next Week’s Motorway Closures
Recent Posts
Your Latest Comments
6 Comments
Does anyone know what this 7 year cycle is? I have searched around some, but can’t find why there would be such a cycle?
does this mean that spring is on its way! (Hope so)
See attached tide tables for Auckland. These are relatively high tides however there are plenty of high 3.5m and 3.6m tides throughout the year so they are not really special. These values are predicted only and can change with weather patterns. As an example 1mb in pressure = 1cm in height. I believe standard is around 1015mb
http://www.linz.govt.nz/docs/hydro/tidal-info/tide-tables/maj-ports/Auckland/pdf/2010.pdf
Have never really understood why they have not installed stopbanks along the causeway ?
The 3.6 a few months ago didn’t go on the roads, except for a short patch in Tamaki Drive, so I don’t think a 3.4 will cause any issues unless combined with very high winds pushing up some big waves.
This whole 6 to 7 year cycle thing has been mindlessly repeated by journalists since the first tidal flooding this year.
I have no idea where they came up with the idea from.
The tides have a high low cycle of 12 hours due to the earths rotation. On top of that there is a monthly cycle depending on the relative position of the sun and the moon as the moon revolves around earth. On top of that there is also a monthly cycle caused by the eccentricity of the moons orbit around the earth. There is also probably a yearly cycle caused by the earth’s eccentricity around the sun but this is going to be pretty negligable.
So we get spring tides every two weeks or so, when the high tide corresponds to either a full or new moon.
We get slightly higher spring tides every few months when the high tide corresponds to a full or new moon when the moon is at perigee. And we might get an even more slightly higher high tide once a year when the high tide corresponds to a new or full moon when the moon is at perigee and the earth is at perihelion (this is over summer for NZ).
And as people have already mentioned, the atmospheric pressure and wind direction can have quite noticeable effects on the tide height. In the extreme case of a cyclone, the sea level can raise almost 2m above normal.
So yea, every few months this flooding will take place, just like it has done every few months for as long as I can remember, and just like it will continue every few months into the future.
Its nice the transit agency has started warning people about it, but im not sure why they are treating it like a crazy weird thing that is happening this year and this year only.
If you are conspiracy-minded, you could say they are doing it to drum up support for the causeway works / widening