Kia ora Kevin

Thank you for your email. We acknowledge receipt of your OIA request below.

We will respond as soon as possible and no later than Monday 19 August 2024, being 20 working days after the day your request was received. If we are unable to respond to your request by then, we will notify you of an extension of that timeframe.

Ngā mihi
Sarah

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Kia ora Kevin

We have transferred part of your request to GNS as the information to which your request relates, namely the last question relating to vertical rise, is not held by us but is believed to be held by is believed to be more closely connected with the functions of GNS.

In these circumstances, we are required by section 14 of the OIA to transfer your request.

You will hear further from GNS concerning that part of your request.

Ngā mihi
Sarah

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Kia ora Kevin,

We accept the partial transfer request from NIWA for the last question relating to vertical rise from and acknowledge receipt of your OIA request below.

We will respond as soon as possible and no later than Wednesday 11 September 2024, being 20 working days after the day your request was received by GNS Science. If we are unable to respond to your request by then, we will notify you of an extension of that timeframe.

Ngā mihi,
Trinita

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Kia ora Kevin

 

Please find responses to your request below.

 

 

1.      A sea level buoy has recently been deployed in Westport.

We understand WCRC has already responded to you on this matter.

 

2.      I am requesting correspondence about the level measuring equipment
that was used for previous recordings.

The chart at the beginning of the recent publication 'West Coast Region
Coastal Hazards mapping methodology shows plots for Charleston and
Westport.

This NIWA and WCRC booklet is dated 29 April 2024.

Could you please provide copies of the correspondence pertaining to those
two sites?

I am seeking info on the data gathering, site maintenance, site
calibrations and the compensation methods applied.

ie, How the data was obtained, how it was checked and then what
atmospheric and sea pressures, temperatures and tidal factors were
subsequently applied.

[1]A graph with red and blue lines Description automatically generated

The figure above is the one you refer to. It summarises the mean sea level
from several tide gauges on the South Island. Data is presented in annual
means (averaged value for the year but years with less than 80% of data
coverage were rejected) and vertically shifted to an arbitrary common
datum of Mean Sea Level for 2000 (so all gauges are at 0.0 for the year
2000) for visualisation purposes.

 

The Lyttelton data is from Stats NZ coastal sea level database. You can
find original data here
[2]https://www.stats.govt.nz/indicators/coa...). This
dataset has been corrected for atmospheric pressure and quality
controlled. See details here:
[3]https://environment.govt.nz/assets/publi....

 

The Charleston data is from the NIWA-operated Charleston gauge (site
92899). No atmospheric pressure correction was applied. The pressure
sensor is a Paroscientific, and is part of a bubbler system using
compressed nitrogen. The recorder is a Campbell CR10 with cellphone
telemetry, recording every 5 minutes to a resolution of 1 mm. NIWA
Greymouth team operated the sensor from Sept 1997 until June 2011, with
audited data. The whole-of-record data review document is attached. LINZ
has operated the gauge since 2015.

 

The Jacksons Bay data is from the Australian Bureau of Meteorology (BoM)
Database from 1998 to 2012 for site 186299 (12 min data) and, from 2013 to
2023, for site IDO70014 (1 min data).  No atmospheric pressure correction
was applied to the BoM data.

 

The Westport data is from the Port archive data as provided to us.
Questions as to whether any atmospheric pressure corrections were applied
or how data has been quality controlled would have to go to the Port.

 

3.      The same document refers to LiDAR measurements.

Could you please advise what vertical changes have been detected in the
Buller coastal region over the past decades ?

I have heard from a local surveyor that a rise in ground level has been
recorded.

This would be by a number of measuring techniques so I am interested in
the rate of rise and the method used.

 

We have transferred this part of your request to GNS, as it is not
information we hold.

 

Please note, under section 28(3) of the Act, you have the right to seek an
investigation and review by the Ombudsman of this decision.

 

Ngā mihi

Sarah

 

 

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Dear Kevin,

Please find attached the response from GNS Science to your Official Information Act request transferred in part by NIWA.

Anna Jellie (she/her)
General Counsel
GNS Science Te Pῡ Ao
D +64 4 570 4736
1 Fairway Drive, Avalon
Lower Hutt, New Zealand
http://www.gns.cri.nz/

This email may contain legally privileged information. No privilege is waived or lost by any mistransmission.

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