Estimate of eleven components of the national and regional water balance of New Zealand.

The National Institute of Water and Atmospheric Research Ltd (NIWA) has been commissioned by the Ministry for the Environment to estimate 11 components of the national and regional water balance of New Zealand for each of the 20 years from 1 July 1994 to 30 June 2014. This information is for use by Statistics New Zealand in a set of annual national water accounts they are developing, as part of a set of environmental accounts for New Zealand. Specifically, this work is a contribution to the Water Physical Stock Accounts. The data were analysed to summarise the water stock accounts of New Zealand and the 16 regions administered by regional councils or unitary authorities,using a combination of direct measurement and modelled data. The average annual precipitation across the country was 550,000 m3/year (equal to over nine times the volume of Lake Taupo), a reduction from previous years’ calculations. Roughly 20% of this evaporates before reaching the coast, leaving an average of 440,000 million m3/year. There is substantial variation in this water flux from year to year due to a range of climatic factors. Changes in storage – lakes, soil moisture, snow, and ice – represent very small components of the annual water balance. Use of water for hydroelectric power generation represents a significant portion of the nation’s freshwater resource, equating to 36% of the total freshwater flows, but this figure includes multiple use of water within the same catchment. Water fluxes at the regional scale vary depending on the region’s size as well as the spatial variability in the delivery and movement of water. The West Coast receives the largest portion of precipitation – 26% of the national total – and possesses 30% of the nation’s freshwater flow. Nelson City, due to its small size, accounts for the smallest portion in both cases. Canterbury accounts for the greatest portion of hydro-generation water use (mainly for the Waitaki scheme), followed by Waikato. Data are for 11 water balance components: 1. Precipitation 2. Inflows from rivers (regional scale only) 3. Evapotranspiration 4. Abstraction by hydro-generation companies 5. Discharges by hydro-generation companies 6. Outflows to sea from surface water 7. Outflows to other regions (regional scale only) 8. Net change in lakes and reservoirs 9. Net change in soil moisture 10. Net change in snow 11. Net change in ice
 
Citation proposal
Christian Zammit (NIWA) - Andrew Willsman (NIWA) - Roddy Henderson (NIWA). .
 

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Date ( Creation )
2015-06-16T04:55:00
Date ( Revision )
2015-06-16T04:55:00
Purpose
This work contributes to the New Zealand Water Physical Stock Accounts. The report summarises the water stock accounts for the whole of New Zealand and 16 regions administered by regional councils or unitary authorities. 
Credit
Collins, D., Zammit, C., Willsman, A., Henderson, R. (2015). Surface water components of New Zealand’s National Water Accounts, 1995-2014. NIWA CLIENT REPORT No: CHC2015-013. NIWA Project: MFE15501. p. 15. Funding from the Ministry for the Environment. 
Status
Completed  

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Spatial representation type
Vector  
Topic category
  • Inland waters
Description
New Zealand 
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S
E
W


TimePeriod
1994-07-01T00:00:002014-06-30T00:00:00 
  • Water Balance, national, regional, surface water components.
NIWA Project Codes
  • MFE15501
Use limitation
Data are obtained from many sources: national databases, regional councils, NIWA. Contact NIWA point-of-contact (email details above) in the first instance. 
Other constraints
The 11 components are estimated by a combination of direct calculation from measurements, spatial mapping/modelling, and hydrological modelling. Thus data comes from a combination of national databases, regional councils, unitary authorities and NIWA. 
Use limitation
Data are obtained from many sources: national databases, regional councils, NIWA.Contact NIWA point-of-contact in the first instance. 
Classification
Restricted  
Title
Collins, D., Zammit, C., Willsman, A., Henderson, R. (2015). Surface water components of New Zealand’s National Water Accounts, 1995-2014. Prepared for Ministry for the Environment. March 2015. NIWA CLIENT REPORT No: CHC2015-013. NIWA Project: MFE15501. p. 15. 
Association Type
Larger work citation  
Language
English  
OnLine resource

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OnLine resource

MFE15501, Water Accounts Update

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Metadata identifier
b5e76268-5abc-6b4a-60f7-a5e8a0d56521

Language
English  
Character encoding
UTF8  

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Dataset  
Date info ( Creation )
2015-06-17T16:26:06
Title
ISO 19115-3 
 
 

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