The Highly Erodible Land (HEL) system identifies land highly susceptible to mass-movement erosion using a combination of the erosion terrains derived from the NZLRI database, a 15‑metre digital elevation model (DEM) to determine topography, and land cover mapping. It considers the main forms of mass-movement erosion in New Zealand (landsliding, earth flows, and massive gullying).
Highly erodible land was defined as “land with the potential for severe erosion if it does not have protective woody vegetation” and was identified by:
The procedure produces five classes of HEL:
Because it uses the DEM to identify slopes, the HEL system is capable of higher spatial resolution than the NZLRI approach alone. At present the land cover map is derived from Ecosat (~2001), but this may be readily updated to 2008 using LUCAS. HEL was first piloted in the Manawatu–Whanganui region and forms the basis of their SLUI programme (http://www.mpi.govt.nz/environment-natural-resources/funding-programmes/slm-hill-country-erosion-programme/slmhce-project-sustainable-land-use-initiative). It was subsequently widened to include the whole of the North Island (Dymond et al, 2008), and now North Island regional councils use it for soil conservation planning. MAF also use it to evaluate regional council requests for soil conservation funds.
HEL identifies land that is highly erodible. It identifies steep land that is at risk of mass movement. It identified land that should be under forest to reduce the erosion risk..
|Latest Version||Version 1|
|State of Development||Released and final|
|Current Development Activity||None|
|Management Domains||Land, Natural Hazards, Freshwater|
|Intended End Users||Land managers, Policy makers|
|Steady State or Dynamic||Dynamic|
|Level of Integration||Environmental|
|Key Input Data||Land Cover Geology and soils. slope and elevation|
|Input Data Formats||Raster-format (Imagine)|
|Key Output Data||Erosion risk|
|Output Data Formats||Raster-format (Imagine)|
|Open/Closed Source||Open Source|
|Licence Type||Data licence|
|Licence Purchase Contact||
+64 6 353 4800 Landcare Research
Private Bag 11052 Manawatu Mail Centre Palmerston North 4442
|Operating Systems||MS Windows, Linux|
|User Interface||Graphical desktop|
|Ease of Use||Easy Just put in a land cover file and press run.|
|Use in Policy Process||Plan (Policy Formulation), Do (Policy Implementation), Check (Policy Evaluation), Review (Issue Identification)|
Dymond, John, Shepherd, James, Page, Mike (No date) Rollout of erosion models for regional councils. Report, Landcare Research, 37 pages.
|Support||No formal support, but you can ring John Dymond.|
|Programming Language||Imagine Spatial Modeller|
|Methods included for calibration and validation||Synthesis of published literature.|
|Methods included for managing uncertainty||Not Applicable. (At risk or not)|
|Keywords||erosion risk, land sliding, earth flow, gully erosion, sediment, land cover|
|Linkages to other Models|
Dymond JR, Ausseil A-G, Shepherd JD, Buettner L 2006. Validation of a region-wide landslide risk model. Geomorphology 74: 70–79. Dymond JR, Jessen MR, Lovell LR 1999. Computer simulation of shallow landsliding in New Zealand hill country. International Journal of Applied Earth Observation and Geoinformation 1(2): 122–131.