The New Zealand Landslide Database (NZLD) has been established to save lives, and help infrastructure owners and planners understand landslide risk – New Zealand’s “forgotten natural hazard”.
To manage the risks from landslides it is essential to have a comprehensive landslide database (“landslide inventory”). Without this consolidated, consistent and quality assured landslide inventory any efforts to assess spatial landslide hazard or risk will be limited. Landslide hazard assessments are greatly enhanced if they include information on the magnitude, encompassing the distribution, type, density, size and impacts of landslides, and temporal frequency of past landslide events. The on-going capture of landslide records provides the magnitude and temporal frequency of landslide activity and its relationship with terrain types and individual triggering events, and this increases the reliability of landslide hazard and risk assessment (Rosser et al., 2017).
Jointly funded and managed by The Earthquake Commission (EQC) and Auckland Council, the database is modelled on the successful New Zealand Geotechnical Database and provides a central repository to catalogue landslide information from councils, Crown entities and geotechnical consultants.
A key feature of the database is it’s online, cross-organisation structure that allows landslide data to be easily entered in a single location by all the relevant organisations.
EQC chief resilience and research officer Jo Horricks said the project, initiated by Auckland Council, would become an important tool for future planning.
“It’s about reducing risk so New Zealand is more disaster resistant – a big part of that is building in the right areas. We think of earthquakes and volcanoes, but landslides tend to be the forgotten natural hazard.”https://www.stuff.co.nz/national/123584266/landslide-database-established-to-save-lives-from-the-forgotten-hazard
GNS Science research has identified around 1800 fatalities from landslides over the past 160 years, which is significantly more than earthquakes casualties over the same period, and that landslides cost the country an average of $250-$300 million each year.
Contributing bodies GNS Science, KiwiRail, Waka Kotahi and Auckland Council already hold large amounts of information on slips, and it is expected that other groups and authorities would contribute over time. The NZLD allows data from across the different institutions to be standardised and could also be used to predict landslides.
“This will give us a much better understanding of vulnerable land, which is the deciding factor for damage from natural hazards. To build more resilient buildings, we need to know where landslides exist and where they may occur in the future,” says Horrocks.https://www.geplus.co.uk/news/new-zealand-developing-national-landslide-database-07-12-2020/
Governance and operational management
The database is co-funded by EQC and Auckland Council, and managed on a day-to-day basis by Auckland Council. It was developed and is currently hosted by Beca, operating as supplier to Auckland Council.
The database is governed by a set of key stakeholders, with the responsibility to ensure that it is used appropriately, well maintained and structured in a way that makes it valuable for all their stakeholder organisations:
- Auckland Council – Ross Roberts
- EQC – Natalie Balfour
- GNS Science – Sally Dellow
- KiwiRail – Daniel Rodriguez
- Waka Kotahi (NZTA) – Stuart Finlan
The following members of the technical working group provided highly valuable advice during design and development of the database:
- Alex Kelly (Auckland Council)
- Brenda Rosser (GNS Science)
- Rosie Tate (GNS Science)
- Steve Raynor (Tauranga City Council)
- Susan Tilsley (Beca)
- Tracy Howe (University of Auckland / Auckland Council)
The steering group providing technical input during database development included those listed above, as well as Chris Massey (GNS Science), Claudia Harford (Auckland Council), David Barrell (GNS Science), Kiran Saligame (MBIE), Lukas Janku (KiwiRail), Phil Mourot (Waikato Regional Council), Roger Fairclough (NZ Landslides Steering Group) and Warren McLuckie (Beca).
The database comprises two individual elements:
- A public reporting tool, to allow anyone to submit key information about landslides for review. This is a simple form designed for use by anyone to collect the basic information required for decision-making by experts. It can be accessed here: https://landslidespublic.beca.digital/
- The main database, containing detailed information about each landslide. This is accessible only to registered users, with the intent being that these are limited to Professional Engineering Geologists (PEngGeol) or others with similar levels of understanding about landslides. Registered users can access it here: https://app.facilitytwin.com/
Each landslide has its own unique identifier, and a table of core metadata. Additional data can be added to this over time. A basic schematic of the structure is shown below:
Key features of this database include:
Only physical attributes of the landslide are recorded, to avoid hosting confidential information. The Landslide ID can be used within organisations to link the landslide to this confidential information.
- The master dataset for each landslide isn’t linked to a location. This allows a landslide to be added even when its location isn’t precisely known, as is commonly the case when a landslide is first reported. This eliminates the issue of landslide features being arbitrarily mapped even when the data doesn’t support detailed mapping.
- Mapping can be added and changed over time as more information becomes available, or as the landslide evolves.
- A history is recorded showing how the data has changed over time.
- Reports, sketches, photographs etc. can be attached to the record.
- Ground investigation data can be entered into the New Zealand Geotechnical Database and represented in this database.
- The mapping can be provided as a Web Map Service into client organisations to show the landslide inventory within internal systems.
- A quality assurance process is built into the database.