LENZ - Monthly water balance ratio

27 May 2010

This dataset was first added to LRIS Portal on 27 May 2010.

Monthly water balance ratio data layer used in the creation of Land Environments of New Zealand (LENZ) classification. The classification layers have been made publicly available by the Ministry for the Environment (see data.mfe.govt.nz/layers/?q=LENZ for to access these layers).

This layer differentiates between regions that have minimal water deficit, but vary markedly in the total amount of rainfall they receive. Based on a water balance model using monthly estimates of mean daily temperature, mean daily solar radiation, and mean rainfall. This layer is the annual average of the monthly ratios of rainfall to potential evaporation calculated using the method of Priestley and Taylor (1972). The resulting 100 metre layer (The temperature, solar radiation and rainfall layers were all 100m) was then interpolated to 25 metres using bilinear interpolation.

The climate station data used in the development of this climate surface were derived from summaries of climate observations published by the New Zealand Meteorological Service, using data collected over the period from 1950-1980 The data layer was derived from surfaces fitted to monthly data describing daily average temperature, daily solar radiation and monthly rainfall. The rainfall surface was fitted using NZMG coordinates, elevation, and a model describing relationships between topography and westerly winds. Having derived the 36 input climate layers, an empirical model was first used to calculate the monthly potential evaporation from the monthly estimates of solar radiation and temperature. These estimates of evaporation were then compared with the monthly rainfall estimates. To calculate the monthly water balance ratio, the ratio of rainfall to evaporation was computed for each month, and then the average of these twelve ratios was calculated.

Additional details such as the climate station locations used in the creation of the layer are defined in the attached LENZ Technical Guide.

Layer ID 48093
Data type Grid
Resolution 25.000m
Services Raster Query API, Catalog Service (CS-W), data.govt.nz Atom Feed



Creative Commons Attribution 3.0 New Zealand

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04 Aug 2017

This dataset was last updated on LRIS Portal on 04 Aug 2017.

This is a binary mask layer for the Earning Capacity Rental project - identifying all areas that by definition (forested or water body) will have BASE carrying capacity set to zero (0 SU/ha). All other areas are set to one (unity). The final BASE carrying capacity is derived by multiplying the result of the regression models by this binary mask leavibng model values either unchanged or reset to zero. For use with both Model 1 and Model 2.

Layer ID 48314
Data type Image/Raster
Resolution 25.000m
Services Raster Tiles Query API, Catalog Service (CS-W), data.govt.nz Atom Feed

Water Yield


Creative Commons Attribution-Noncommercial-No Derivative Works 3.0

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03 May 2018

This dataset was last updated on LRIS Portal on 03 May 2018.

This layer represents the net supply of water remaining after evapo-transpiration losses (mm/yr) as an indicator of water- flow regulation. Although this is a simplified view and does not consider low flows or flood flows, it permits national assessment with the use of a nationally applicable water-balance model (similar to the tier 1 approach in Kareiva et al. (2011)). WATYIELD (Fahey et al., 2010) models daily water transfers of rainfall, interception, evapotranspiration, and drainage associated with a soil profile. Input data to the model are daily rainfall and daily potential evapotranspiration (PET). Parameters required for the model included the fraction of intercepted rainfall, vegetation factors for transpiration, and total and readily available water holding capacity of the soil.

Layer ID 95385
Data type Grid
Resolution 100.000m
Services Raster Query API, Catalog Service (CS-W), data.govt.nz Atom Feed