Creative Commons Attribution 3.0 New Zealand
You may use this work for commercial purposes.
You must attribute the creator in your own works.
This dataset was first added to MfE Data Service on 11 Jan 2016.
ca65a8ec-6164-3b15-e22c-2860957ab194
eng
utf8
dataset
dataset
Environmental Reporting, Ministry for the Environment and Statistics New Zealand
Analyst
23 Kate Sheppard Place, PO Box 10362
Wellington 6143
New Zealand
Environmental.Reporting@mfe.govt.nz
distributor
2016-01-21
ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata
1.1
2193
Water clarity trends, 2009–2013
Water clarity is a measure of underwater visibility in rivers and stream. Water clarity can be reduced by the presence of fine particles like silt, mud or organic material in the water. This affects the habitat and feeding of aquatic life like fish and aquatic birds. Water clarity is an important indicator of the health of a waterway, and is also a consideration for recreational activities like swimming and wading.
This dataset relates to the "River water quality trends: clarity" measure on the Environmental Indicators, Te taiao Aotearoa website.
completed
Environmental Reporting, Ministry for the Environment and Statistics New Zealand
Analyst
23 Kate Sheppard Place, PO Box 10362
Wellington 6143
New Zealand
Environmental.Reporting@mfe.govt.nz
distributor
irregular
*.xml
Unknown
New Zealand
theme
ANZLIC Jurisdictions
Version 2.1
2008-10-29
http://asdd.ga.gov.au/asdd/profileinfo/anzlic-jurisdic.xml#anzlic-jurisdic
ANZLIC the Spatial Information Council
custodian
WATER
WATER-Quality
theme
ANZLIC Search Words
Version 2.1
2008-05-16
http://asdd.ga.gov.au/asdd/profileinfo/anzlic-theme.xml#anzlic-theme
ANZLIC the Spatial Information Council
custodian
Creative Commons Attribution 3.0 New Zealand by Ministry for the Environment
license
Creative Commons Attribution 3.0
copyright
Creative Commons Attribution 3.0 New Zealand by Ministry for the Environment
license
eng
utf8
environment
ANZMet Lite Country codelist
Version 1.0
2009-03-31
http://asdd.ga.gov.au/asdd/profileinfo/anzlic-country.xml#Country
ANZLIC the Spatial Information Council
custodian
nzl
https://data.mfe.govt.nz/layer/52685-water-clarity-trends-20092013/
dataset
dataset
Source:
NIWA
Method:
Water clarity is measured using a black disc the size of a soccer ball. The disc is placed in the water, and viewed through an underwater viewing box at increasing distances until the black disc disappears from sight. This provides a consistent measure of the greatest distance an object can be seen through the water (Davies–Colley, 1988).
NIWA have measured monthly water clarity consistently at 77 sites along 35 major rivers between 1989 and 2013. These 35 rivers drain about 50 percent of New Zealand’s land area. This long–term measurement data is particularly useful for tracking changes in water clarity over time (Ballantine and Davies Colley, 2014). Trends over shorter time periods can be assessed using regional council data. However, these monitored sites are not representative of the national river network because they tend to be located in more problematic areas.
The data was flow–adjusted before trend analysis, to remove the influence of variation in stream flow. Flow adjustment means the reported trends better reflect for the effects of controlling factors other than flow.
The accuracy of the data source is of high quality.
Reference:
Ballantine, DJ & Davies–Colley, RJ (2014). Water quality trends in New Zealand rivers: 1989–2009. Environmental Monitoring and Assessment, 186(3), 1939–1950.
Davies–Colley, RJ (1988). Measuring water clarity with a black disc. Limnology and Oceanography, 33(4), 616–623. Accessed 18 August 2015 from www.horizons.govt.nz.
Creative Commons Attribution 3.0 New Zealand by Ministry for the Environment
license
Creative Commons Attribution 3.0 New Zealand by Ministry for the Environment
license