MIKE SHE Public Data Catalog¶

New Zealand¶

Version: 0.1 test template
Purpose: Country-specific public dataset catalog for building simple to advanced MIKE SHE models
Region: New Zealand (North Island, South Island and nearby islands)

Quick Start¶

Minimum Public Datasets for Recharge Modelling with MIKE SHE (New Zealand)¶

If your objective is to calculate distributed groundwater recharge (without simulating groundwater flow or rivers), only five dataset categories are required.

The datasets below cover the whole of New Zealand and provide an excellent starting point for building a physically based recharge model. Most are free under CC BY 4.0; access conditions for gridded climate data are noted below.

MIKE SHE Input	Dataset Type	Recommended Dataset	Spatial Availability	Why recommended
Topography (DEM)	Gridded	LINZ national elevation data – LiDAR 1 m DEM where available, NZ 8 m DEM elsewhere	New Zealand	National LiDAR now covers most of the country at 1 m, with the 8 m DEM as a seamless national fallback for defining slopes, drainage pathways and overland-flow gradients.
Land Cover	Vector / gridded	Land Cover Database (LCDB)	New Zealand	Standard national land-cover map with several epochs since 1996, suitable for assigning vegetation types, impervious areas and overland-flow parameters.
Soil Hydraulic Properties	Vector	S-map where available Fundamental Soil Layers (FSL) for full coverage	S-map: most productive land FSL: New Zealand	S-map provides soil layering, drainage class, saturated hydraulic conductivity and water retention for each soil sibling. FSL fills gaps in hill and high country at a coarser level.
Precipitation	Gridded	NIWA Virtual Climate Station Network (VCSN) for daily, long-term modelling ERA5-Land as a fully free hourly alternative	New Zealand	VCSN is the national standard daily climate grid (~5 km) interpolated from station data. Check NIWA access and licence conditions, especially for commercial use. ERA5-Land is freely available but coarse for New Zealand's steep rainfall gradients.
	Time Series	CliFlo (NIWA National Climate Database) Regional council rainfall networks	Nationwide (station-dependent)	Recommended whenever reliable local rain-gauge observations are available. Regional councils often operate denser networks than the national database.
Meteorological Forcing / Potential ET	Gridded	NIWA VCSN	New Zealand	Provides daily Penman and Priestley-Taylor PET together with temperature, vapour pressure, solar radiation and wind speed in one spatially consistent product.
	Time Series	CliFlo Regional council climate stations	Nationwide (station-dependent)	Appropriate when complete local meteorological observations or calculated PET time series are available. These data can be assigned directly to climate zones or used to calculate potential evapotranspiration within MIKE SHE.

Optional Improvements¶

Dataset	Purpose
OpenTopography – New Zealand LiDAR	Direct access to LiDAR point clouds and DEM tiles
Irrigated land area (MfE)	Mapping of irrigated areas
MODIS MCD15A3H	Dynamic Leaf Area Index (LAI)
Sentinel-2	Verification and updating of land-cover maps
MODIS MOD16 / SSEBop	Validation of simulated actual evapotranspiration (OpenET does not cover New Zealand)
Regional council lysimeter data	Direct validation of drainage / recharge (e.g. Canterbury)
SMAP	Regional soil-moisture validation

Recommended Workflow¶

Download the LINZ LiDAR DEM (or the NZ 8 m DEM where LiDAR is missing).
Delineate the model domain and prepare the terrain model.
Download LCDB for the simulation period and assign MIKE SHE vegetation classes.
Download S-map and FSL and derive soil hydraulic parameters.
Choose your meteorological forcing:
Option A (recommended): Use NIWA VCSN for a fully gridded daily model setup, supplemented by ERA5-Land where hourly forcing is needed.
Option B: Import precipitation and meteorological observations from CliFlo or regional council stations directly into MIKE SHE.
Let MIKE SHE calculate evapotranspiration internally using the selected vegetation and soil parameters.
Check simulated drainage against lysimeter data where available.
Export the distributed groundwater recharge for use in MODFLOW, FEFLOW, or other groundwater models.

1. Introduction for advanced data sources¶

1.1 Purpose¶

This document summarizes public datasets that can be used to construct a physically based MIKE SHE model for New Zealand.

The catalog is organized according to the typical MIKE SHE model-building workflow rather than only by dataset type. It covers datasets for:

terrain and overland flow
land cover and vegetation
meteorological forcing
potential and actual evapotranspiration
snow and glaciers
rivers, lakes, and wetlands
soil and unsaturated-zone parameterization
groundwater and hydrogeology
water takes, irrigation, and water management
calibration and validation

1.2 Intended Use¶

This catalog is intended for:

rapid screening models
regional water-balance models
groundwater recharge and nitrate leaching studies
surface-water / groundwater interaction studies, including braided rivers and spring-fed streams
irrigation and water-allocation assessments
flood and catchment studies
applied MIKE SHE model setup

1.3 General Notes for New Zealand¶

National datasets from LINZ and the Ministry for the Environment (MfE) are generally released under CC BY 4.0. Some Manaaki Whenua – Landcare Research and NIWA products (e.g. S-map, VCSN) have their own licence terms, which may restrict commercial use. Always check before use.
NIWA and GNS Science were merged into Earth Sciences New Zealand in 2025. Some portals and links may move as a result.
The national datum is NZGD2000, and models typically use NZTM2000 (EPSG:2193). The national vertical datum is NZVD2016; older data may refer to local vertical datums.
Most groundwater, streamflow, and water-take data are held by the regional councils and unitary authorities (see Section 22), not by national agencies.
Engagement with iwi and hapū is an integral part of freshwater projects, and mātauranga Māori can be an important source of catchment knowledge.

2. Hydrological Characteristics of New Zealand¶

2.1 Climate¶

New Zealand covers very strong climatic gradients over short distances:

temperate maritime climate with prevailing westerly airflow
extreme west–east rainfall gradient across the Southern Alps, from several metres per year on the West Coast to around 350 mm per year in Central Otago
subtropical climate in Northland
drought-prone eastern regions (e.g. Hawke's Bay, Canterbury, Marlborough)
ex-tropical cyclones and atmospheric rivers causing extreme floods (e.g. Cyclone Gabrielle, 2023)
seasonal snow and glaciers in the Southern Alps and central North Island volcanoes
climate variability linked to ENSO and the Southern Annular Mode

2.2 Topography¶

Major topographic settings include:

Southern Alps and steep mountain catchments
Canterbury Plains with braided rivers and large alluvial fans
Taupō Volcanic Zone and central North Island volcanic plateau
Waikato and Hauraki lowlands with extensive peat soils
intermontane basins of Otago and Marlborough
coastal plains (e.g. Heretaunga, Manawatū, Waimea)
steep, erodible hill country on the east coast of the North Island

2.3 Major Hydrological Challenges¶

Important New Zealand modelling challenges include:

nitrate leaching from intensive agriculture and long groundwater lag times
losing braided rivers that recharge major gravel aquifers
spring-fed lowland streams depending on groundwater
irrigation expansion and water allocation limits
flash floods, landslides, and sediment in steep catchments
peat subsidence and drainage in lowland areas
seawater intrusion in coastal aquifers
snowmelt and glacier contributions in alpine catchments
highly permeable volcanic soils and ignimbrites
nutrient loads to lakes (e.g. Lake Taupō, Rotorua lakes)

2.4 Major Aquifer Systems¶

Important aquifers include:

Canterbury Plains gravel aquifers (including the Christchurch–West Melton system)
Heretaunga Plains aquifer system (Hawke's Bay)
Wairau Aquifer (Marlborough)
Waimea Plains aquifers (Tasman)
Waiwhetū Artesian Aquifer (Hutt Valley, Wellington)
Taupō Volcanic Zone ignimbrite aquifers (e.g. Rotorua)
Auckland volcanic field basalt aquifers
Arthur Marble Aquifer and Te Waikoropupū Springs (Tasman, karst)
Ruataniwha Basin (Hawke's Bay)
Southland and Otago alluvial aquifers

3. Recommended Dataset Stack¶

Component	Recommended Dataset	Alternative Dataset	Importance
DEM	LINZ LiDAR 1 m DEM	NZ 8 m DEM (LINZ), Copernicus GLO-30	★★★★★
Land cover	LCDB	ESA WorldCover	★★★★★
Land use / irrigation	MfE land use and irrigated land	Regional council mapping	★★★★☆
LAI	MODIS MCD15A3H	Sentinel-2 derived LAI	★★★★☆
Precipitation	NIWA VCSN	CliFlo, regional councils, ERA5-Land	★★★★★
Climate forcing	NIWA VCSN	ERA5-Land	★★★★★
Potential ET	NIWA VCSN	CliFlo stations	★★★★★
Rivers	River Environment Classification (REC2)	LINZ Topo50 hydrography	★★★★★
Lakes / wetlands	FENZ (DOC)	LINZ Topo50, LCDB	★★★★☆
Soil	S-map	FSL / NZLRI	★★★★★
Hydrogeology	GNS Science geological maps and aquifer data	MfE aquifer boundaries	★★★★★
Groundwater heads	Regional councils (Section 22)	LAWA	★★★★★
Water takes	Regional council consent and metering data	MfE national summaries	★★★★☆
Streamflow calibration	Regional councils / NIWA hydrometric network	LAWA	★★★★★
Actual ET validation	MODIS MOD16	SSEBop, eddy-covariance sites	★★★☆☆
Recharge validation	Regional council lysimeters	Groundwater age dating (GNS)	★★★★☆
Soil moisture validation	CliFlo soil moisture sites	SMAP	★★★☆☆

4. Terrain Model¶

4.1 Purpose in MIKE SHE¶

Terrain data are required for:

model surface elevation
overland-flow gradients
surface-storage controls
catchment delineation
river network verification
floodplain and wetland connectivity

4.2 Dataset Comparison¶

Dataset	Coverage	Resolution	Format	MIKE SHE Suitability	Advantages	Limitations	Recommendation
LINZ LiDAR DEM	Most of New Zealand	1 m	GeoTIFF	Primary DEM	High accuracy, bare-earth, national programme	Survey dates vary by region; large volumes	★★★★★
NZ 8 m DEM (LINZ)	New Zealand	8 m	GeoTIFF	Regional models and gap filling	Seamless national coverage	Derived from contours; less accurate on flat land	★★★★☆
OpenTopography NZ	LiDAR survey areas	1 m / point cloud	LAZ / GeoTIFF	Custom DEM processing	Point clouds available	Processing required	★★★★☆
Copernicus GLO-30	Global	30 m	GeoTIFF	Backup DEM	Consistent coverage	Coarse for steep terrain	★★☆☆☆

4.3 Typical Preprocessing¶

reproject to NZTM2000 and check vertical datum (NZVD2016)
clip to model domain plus buffer
merge LiDAR survey tiles and fill gaps with the 8 m DEM
condition channels and remove culvert and bridge artefacts
resample to model grid
compare drainage paths with REC2 streams
smooth only where needed for numerical stability

4.4 Quality Checks¶

confirm river channels follow topographic lows
check braided river beds, which change after floods
check stopbanks (levees) and drainage channels on lowland floodplains
check peat areas for subsidence since the LiDAR survey date
compare derived catchments with REC2 catchments

5. Surface Water¶

5.1 Rivers¶

Dataset	Coverage	Format	MIKE SHE / MIKE 1D Use	Advantages	Limitations	Recommendation
River Environment Classification (REC2)	New Zealand	Vector GIS with topology and attributes	River network, catchments	National river network with classification and flow statistics	Requires simplification for hydraulic routing	★★★★★
LINZ Topo50 hydrography	New Zealand	Vector GIS	Rivers, lakes, drains	Official topographic mapping	Less topology than REC2	★★★★☆
HydroRIVERS	Global	Vector GIS	Fallback	Global consistency	Too coarse for New Zealand	★☆☆☆☆

5.2 Lakes and Reservoirs¶

Dataset	Use	Recommendation
FENZ (Freshwater Ecosystems of New Zealand)	Lakes, rivers and wetlands with ecological attributes	★★★★☆
LINZ Topo50	Lake polygons	★★★★☆
Hydropower operators and regional councils	Storage levels for hydro lakes	★★★★☆

5.3 Wetlands and Springs¶

Potential sources:

FENZ wetlands (DOC)
LCDB wetland classes
regional council wetland and spring mapping
Sentinel-1 SAR and Sentinel-2

Wetland and spring data are useful for groundwater-dependent ecosystem studies, spring-fed stream baseflow, and surface storage parameterization.

5.4 Typical Preprocessing¶

simplify river network
remove minor branches not relevant at model scale
identify losing and gaining reaches (especially braided rivers)
align river network with DEM
define cross-sections or approximate channel geometry
define river-bed conductance
include drains, stopbanks and hydro schemes where relevant
assign river boundary conditions

6. Land Cover and Vegetation¶

6.1 Purpose in MIKE SHE¶

Land cover and vegetation define:

interception
evapotranspiration parameters
root depth
crop coefficients
Manning roughness
irrigation zones
impervious areas
surface detention/storage behavior

6.2 Dataset Comparison¶

Dataset	Coverage	Resolution	Format	MIKE SHE Use	Advantages	Limitations	Recommendation
LCDB	New Zealand	~1 ha minimum mapping unit	Vector	Primary land-cover zones	National standard with several epochs since 1996	Does not separate dairy from sheep and beef pasture	★★★★★
MfE land use and irrigated land	New Zealand	Vector	Vector	Irrigation zones and land use	Identifies irrigated areas	Snapshot years only	★★★★☆
ESA WorldCover	Global	10 m	Raster	Alternative land-cover map	High resolution	Generic global legend	★★★☆☆
Dynamic World	Global	10 m	Cloud / Earth Engine	Recent land-cover dynamics	Near-real-time	Requires postprocessing	★★★☆☆

6.3 Vegetation Datasets¶

Parameter	Dataset	Use	Recommendation
LAI	MODIS MCD15A3H	Seasonal LAI time series	★★★★☆
NDVI	Sentinel-2 / Landsat	Pasture growth and crop seasonality	★★★★☆
Root depth	LCDB classes + literature	Root-depth assignment	★★★☆☆
Crop coefficient	FAO-56	Pasture and crop ET parameterization	★★★★☆

6.4 Typical Preprocessing¶

reclassify LCDB classes into MIKE SHE vegetation zones
overlay irrigated land maps to separate irrigated and dryland pasture
separate exotic plantation forest, indigenous forest, scrub, tussock, and pasture
consider harvest cycles in plantation forests for long simulations
assign LAI curves or seasonal LAI maps
assign roughness values for overland flow

7. Meteorological Forcing¶

7.1 Precipitation¶

Dataset	Coverage	Resolution	Temporal Resolution	MIKE SHE Use	Advantages	Limitations	Recommendation
NIWA VCSN	New Zealand	~5 km	Daily	Primary rainfall forcing	National standard, long record	Access and licence conditions; underestimates alpine rainfall	★★★★★
CliFlo	Station network	Point	Daily / hourly / sub-hourly	Station forcing and bias correction	Free, long records	Uneven coverage in mountains	★★★★☆
Regional council rain gauges	Regional	Point	Sub-hourly	Event forcing	Dense local networks	Different portals per council	★★★★★
ERA5-Land	Global	~9 km	Hourly	Backup forcing	Free, hourly	Too coarse for orographic gradients	★★☆☆☆

7.2 Climate Variables¶

Variable	Recommended Dataset	Alternatives	MIKE SHE Use
Air temperature	NIWA VCSN	CliFlo, ERA5-Land	ET, snow/rain distinction, snowmelt
Wind speed	NIWA VCSN	CliFlo	Penman-Monteith / Shuttleworth-Wallace
Vapour pressure / humidity	NIWA VCSN	CliFlo	Vapour-pressure deficit
Solar radiation	NIWA VCSN	CliFlo, NASA POWER	ET energy term
Potential ET	NIWA VCSN (Penman, Priestley-Taylor)	CliFlo	PET forcing or validation

7.3 Potential ET¶

Dataset	Coverage	Resolution	Temporal Resolution	Use	Recommendation
NIWA VCSN	New Zealand	~5 km	Daily	Distributed PET	★★★★★
CliFlo	Station locations	Point	Daily	Local PET time series	★★★★☆

7.4 Snow and Glaciers¶

Snow and ice are important in the Southern Alps, the Kaikōura ranges, and on the central North Island volcanoes.

Dataset	Use	Recommendation
NIWA Snow and Ice Network	Alpine snow observations	★★★★☆
NIWA end-of-summer snowline survey	Glacier mass-balance context	★★★☆☆
MODIS Snow Cover	Snow extent validation	★★★★☆

8. Soil Data¶

8.1 Purpose in MIKE SHE¶

Soil data control:

infiltration
water retention
evapotranspiration limitation
recharge generation and nitrate leaching
capillary rise
soil-water storage
runoff generation

8.2 Dataset Comparison¶

Dataset	Coverage	Resolution	Parameters	MIKE SHE Use	Advantages	Limitations	Recommendation
S-map	Most productive land	1:50,000 or finer	Functional horizons, Ksat, water retention, drainage class, profile available water	Primary UZ parameterization	Designed for water and nutrient modelling	Incomplete in hill and high country; licence terms apply	★★★★★
Fundamental Soil Layers (FSL)	New Zealand	1:50,000 to 1:63,360 (NZLRI)	Drainage, profile available water, texture classes	Gap filling	National coverage	Class-based, less detailed	★★★★☆
NZLRI	New Zealand	1:50,000 to 1:63,360	Land units, rock type, slope	Soil and land context	National coverage	Old survey	★★★☆☆
SoilGrids	Global	250 m	Global soil properties	Backup	Easy access	Poorly suited to volcanic and stony soils	★★☆☆☆

8.3 Required Soil Parameters¶

Typical MIKE SHE soil parameters include:

saturated hydraulic conductivity
residual water content
saturated water content
van Genuchten alpha
van Genuchten n
field capacity
wilting point
bulk density
soil layering and stone content

8.4 Typical Preprocessing¶

use S-map functional horizons as MIKE SHE unsaturated-zone layers
fit van Genuchten parameters to S-map water retention values
fill gaps with FSL classes
pay special attention to stony, shallow soils on gravel plains (very high recharge)
treat allophanic and pumice soils (volcanic) separately
resample or rasterize to model grid
check unrealistic Ks values
calibrate sensitive parameters against lysimeter drainage, groundwater heads, and runoff

9. Hydrogeology¶

9.1 Purpose¶

Hydrogeologic data are required for:

defining aquifer boundaries
defining model layers
hydraulic conductivity zones
storage zones
specific yield
groundwater boundary conditions
conceptual groundwater model development

9.2 Dataset Comparison¶

Dataset	Coverage	Use	Advantages	Limitations	Recommendation
GNS Science geological mapping (QMAP)	New Zealand	Geological framework	National 1:250,000 geology	Requires hydrogeological translation	★★★★☆
MfE aquifer boundaries	New Zealand	Aquifer extents	National overview	Generalized	★★★★☆
Regional council aquifer models and reports	Regional	Local aquifer geometry and properties	Most detailed information	Format and access vary	★★★★★
GLHYMPS	Global	Permeability screening	Useful fallback	Too generalized	★☆☆☆☆

9.3 Conceptual Model Recommendations¶

For New Zealand, special attention should be paid to:

highly permeable gravel aquifers with rapid recharge and short response times
losing braided rivers as major recharge sources
spring lines where groundwater re-emerges on lowland plains
confined coastal gravel aquifers and seawater intrusion
volcanic ignimbrite and pumice aquifers with long groundwater ages
karst systems (e.g. Arthur Marble Aquifer)
fault-controlled flow in tectonically active regions
thin soils over fractured greywacke in hill country

10. Groundwater Data¶

10.1 Initial Heads and Monitoring Wells¶

Dataset	Coverage	Use	Advantages	Limitations	Recommendation
Regional council well databases (Section 22)	Regional	Groundwater levels, bore logs	Most complete source	Different portals and formats	★★★★★
LAWA	New Zealand	Groundwater quantity and quality summaries	Nationally consistent overview	Summary level	★★★★☆
GNS National Groundwater Monitoring Programme	New Zealand	Long-term groundwater quality and age	Consistent national sites	Mainly water quality	★★★☆☆

10.2 Water Takes and Pumping¶

Dataset	Coverage	Use	Advantages	Limitations	Recommendation
Regional council consent databases	Regional	Consented takes, locations, rates	Detailed	Consented ≠ actual use	★★★★☆
Water metering data	Regional	Measured takes (telemetered for larger takes)	Actual use	Access via councils	★★★★☆
MfE	New Zealand	National water-take summaries	Consistent	Aggregated	★★☆☆☆

10.3 Boundary Conditions¶

Boundary Type	Source	Comment
Coastal boundary	Coastline and sea level	Important for confined coastal aquifers
River boundary	REC2, regional council flow data	Braided river losses need special care
Spring discharge	Regional council spring gauging	Drain boundaries in MIKE SHE
No-flow boundary	Mountain fronts, basement contacts	Must be justified conceptually
Pumping wells	Regional council consents	Major uncertainty in irrigated areas

11. Water Management¶

11.1 Relevant Processes¶

Water management is often central in New Zealand models:

irrigation (especially Canterbury, Otago, Hawke's Bay, Marlborough)
groundwater and surface-water takes under allocation limits
minimum flows and flow regimes
hydropower schemes (e.g. Waitaki, Waikato, Clutha)
land drainage and flood protection schemes
managed aquifer recharge (e.g. Canterbury)
nutrient limits and farm environment plans

11.2 Regulatory Framework¶

freshwater is managed under the Resource Management Act 1991 (currently under reform)
the National Policy Statement for Freshwater Management (NPS-FM) sets national direction, including limits and Te Mana o te Wai
regional plans set allocation limits, minimum flows, and nutrient rules
Water Conservation Orders protect selected water bodies (e.g. Te Waikoropupū Springs)

11.3 Dataset Sources¶

Topic	Dataset / Agency	Use
Water takes	Regional councils	Consents and metered use
Irrigated areas	MfE irrigated land	Irrigation zones
Allocation limits	Regional plans	Scenarios and zonation
National environmental reporting	MfE / Stats NZ	Context and trends

12. Remote Sensing Products¶

Dataset	Coverage	Resolution	Use	Recommendation
MODIS MOD16	Global	500 m	Regional actual ET validation	★★★☆☆
SSEBop	Global	~1 km	Actual ET validation	★★★☆☆
Sentinel-2	Global	10 m	Land cover, irrigation mapping, vegetation dynamics	★★★★★
Sentinel-1 SAR	Global	10 m	Flood extent under cloud cover	★★★★☆
Landsat	Global	30 m	Long-term land cover and ET support	★★★★☆
SMAP	Global	Coarse	Soil moisture (limited in steep terrain)	★★☆☆☆
MODIS Snow Cover	Global	500 m	Snow extent	★★★★☆
ECOSTRESS	Selected coverage	~70 m	Plant water stress	★★☆☆☆

Frequent cloud cover limits optical remote sensing in many regions; SAR is often more reliable for flood mapping.

13. Calibration Datasets¶

13.1 Recommended Calibration Targets¶

Target	Dataset	Use	Recommendation
River discharge	Regional councils / NIWA hydrometric network	Streamflow calibration	★★★★★
Spring-fed stream flows	Regional council gaugings	Baseflow and groundwater discharge	★★★★★
Groundwater heads	Regional council monitoring wells	Saturated-zone calibration	★★★★★
Drainage / recharge	Regional council lysimeters	Direct recharge validation	★★★★★
Groundwater age	GNS tritium and age-tracer data	Flow paths and residence times	★★★★☆
Actual ET	MODIS MOD16 / eddy-covariance sites	ET plausibility	★★★☆☆
Soil moisture	CliFlo / regional council sites	UZ validation	★★★☆☆
Snow	NIWA Snow and Ice Network / MODIS	Alpine catchments	★★★☆☆

13.2 Recommended Calibration Strategy¶

A robust New Zealand MIKE SHE model should avoid calibration against only discharge. Recommended targets are:

river discharge, including losing reaches of braided rivers
spring-fed stream flows and baseflow
groundwater heads in representative wells
lysimeter drainage where available
groundwater ages to constrain flow paths and lag times
irrigation takes where relevant

14. Typical MIKE SHE Workflow¶

Define modelling objective and domain.
Download and preprocess the LINZ LiDAR DEM.
Delineate catchments and surface drainage.
Build river network from REC2.
Prepare land cover from LCDB and irrigated land maps.
Assign vegetation parameters from MODIS MCD15A3H and literature.
Prepare precipitation from NIWA VCSN and regional council gauges.
Prepare climate forcing and PET from NIWA VCSN.
Prepare soil properties from S-map and FSL.
Build hydrogeological layers from GNS mapping and regional council aquifer models.
Import initial groundwater heads from regional council databases.
Add consented and metered water takes.
Couple rivers and groundwater, with particular care for braided rivers and springs.
Calibrate discharge, spring flows, and groundwater heads.
Validate recharge against lysimeters and groundwater ages.
Document assumptions and uncertainties.

15. Minimum Dataset Package¶

For a simple screening model:

Model Element	Dataset
DEM	NZ 8 m DEM or LiDAR DEM
Land cover	LCDB
Precipitation	NIWA VCSN
Climate forcing	NIWA VCSN
Potential ET	NIWA VCSN
Rivers	REC2
Soils	S-map / FSL
Aquifers	MfE aquifer boundaries
Streamflow	Regional council / LAWA
Groundwater heads	Regional council

16. Recommended Dataset Package¶

For a professional regional MIKE SHE model:

Model Element	Dataset
DEM	LINZ LiDAR 1 m DEM
Sub-daily precipitation	Regional council gauges + CliFlo
Climate forcing	NIWA VCSN
Land cover	LCDB + Sentinel-2 checks
Irrigation	MfE irrigated land + regional council consents
Soils	S-map
Hydrogeology	Regional council aquifer models + GNS mapping
Groundwater heads	Regional council monitoring
Water takes	Regional council consents and metering
Recharge validation	Lysimeters + groundwater age data
Actual ET	MODIS MOD16 / SSEBop

17. Premium Dataset Package¶

For high-quality consulting, regulatory, or research models, add:

Dataset Type	Possible Source	Purpose
LiDAR point clouds and river bathymetry	LINZ / OpenTopography / regional councils	Channel and floodplain geometry
Rain radar	MetService / regional councils	Event-scale rainfall
Metered water-take records	Regional councils	Pumping stress refinement
Regional groundwater models	Regional councils / consultants	Aquifer layering and parameters
Pumping tests	Council records / consultant reports	Hydraulic conductivity and storage
Hydro scheme operations	Hydropower operators	Regulated river boundaries
Farm-scale soil and nutrient data	Farm environment plans / OVERSEER-type assessments	Nitrate leaching and recharge quality
Age-tracer data	GNS Science	Lag times and flow paths

18. Dataset Comparison Table Template¶

Use this table for adding new datasets.

Dataset	Coverage	Spatial Resolution	Temporal Resolution	Time Period	Format	API / Access	License	MIKE SHE Use	Advantages	Limitations	Recommendation
											★☆☆☆☆

19. Data Preparation Checklist¶

Terrain¶

[ ] DEM downloaded
[ ] DEM projected to NZTM2000 and checked against NZVD2016
[ ] DEM clipped
[ ] LiDAR gaps filled
[ ] drainage paths checked

Surface Water¶

[ ] REC2 network downloaded
[ ] river network simplified
[ ] losing and gaining reaches identified
[ ] springs identified
[ ] hydro schemes and drains included
[ ] boundary conditions assigned

Land Cover and Vegetation¶

[ ] LCDB downloaded for simulation period
[ ] classes reclassified
[ ] irrigated areas defined
[ ] forest harvest cycles considered
[ ] LAI assigned
[ ] rooting depths assigned

Weather¶

[ ] VCSN access and licence confirmed
[ ] precipitation downloaded
[ ] regional council gauges added
[ ] climate variables downloaded
[ ] PET checked
[ ] snow parameters defined where relevant
[ ] model forcing files prepared

Soil¶

[ ] S-map and FSL downloaded
[ ] van Genuchten parameters fitted
[ ] soil layers harmonized
[ ] stony and volcanic soils checked
[ ] unrealistic values checked

Groundwater¶

[ ] aquifer boundaries defined
[ ] regional council aquifer models requested
[ ] initial heads interpolated
[ ] water takes added
[ ] boundary conditions defined

Calibration and Validation¶

[ ] discharge gauges selected
[ ] spring flows selected
[ ] groundwater wells selected
[ ] lysimeter data obtained where available
[ ] groundwater age data obtained where available
[ ] calibration and validation periods defined

20. References and Official Data Portals¶

21. Notes on Uncertainty¶

Important uncertainties for New Zealand MIKE SHE models include:

orographic precipitation gradients poorly captured by gauges and grids
alpine precipitation and snowmelt
braided river losses and river-bed conductance
very high and variable conductivity of gravel aquifers
soil hydraulic parameters for stony and volcanic soils
irrigation timing and actual water use
groundwater lag times for nitrate
land-use change (dairy conversion, forestry harvest)
changing river beds after floods
limited satellite ET validation due to cloud cover and steep terrain
aggregation from fine datasets to model-grid resolution

A defensible model should document dataset choices, preprocessing assumptions, calibration strategy, validation results, and known limitations.

22. Regional Council Data Sources¶

In New Zealand, regional councils and unitary authorities hold most groundwater, streamflow, rainfall and water-take data. Most provide an environmental data portal, a well or bore database, and a consents search on their websites.

Region	Council	Key Aquifers / Hydrological Focus
Northland	Northland Regional Council	Coastal sand and basalt aquifers, subtropical storms
Auckland	Auckland Council	Volcanic field basalt aquifers, urban stormwater
Waikato	Waikato Regional Council	Lake Taupō, Waikato River hydro, peat lowlands
Bay of Plenty	Bay of Plenty Regional Council	Rotorua lakes, ignimbrite aquifers
Gisborne	Gisborne District Council	Poverty Bay flats aquifers, erodible hill country
Hawke's Bay	Hawke's Bay Regional Council	Heretaunga Plains and Ruataniwha aquifers
Taranaki	Taranaki Regional Council	Volcanic ring plain, dairy
Manawatū-Whanganui	Horizons Regional Council	Manawatū plains, dairy nutrient management
Wellington	Greater Wellington Regional Council	Waiwhetū Artesian Aquifer, Wairarapa aquifers
Tasman	Tasman District Council	Waimea Plains, Arthur Marble Aquifer, Te Waikoropupū Springs
Nelson	Nelson City Council	Urban catchments
Marlborough	Marlborough District Council	Wairau Aquifer, viticulture irrigation
West Coast	West Coast Regional Council	Extreme rainfall, flood hazard
Canterbury	Environment Canterbury	Canterbury Plains gravel aquifers, braided rivers, lysimeters
Otago	Otago Regional Council	Central Otago basins, irrigation
Southland	Environment Southland	Alluvial aquifers, dairy nutrient management