Landslide Risk Management in Norway

JTC1-TR3, Napoli, 17 November 2015

Outline

A few words about Norway Types of landslides in Norway Climatic and demograhic changes Landslide risk management Research Natural legislation and policy Crisis preparedness Norway

•Area: 300.000km2 •Population: 5.2 mill. •N-S: ca. 2000km •West coast and north, high mountains, deep valleys, fjords, etc.

•NB! Large rural areas. Few cities and many single dwellings.

Some facts - geohazards

• Last 150 years: >2000 deaths from geohazards in Norway • Snow avalanches (1550 deaths), rock-, clay- and debris slides (450 deaths) • Most slides have a meteorological trigger • Extreme precipitation events, snowmelt • 3-4 large catastrophes (>20 fatalities) per 100 years • Frequency, intensity and location of slides may change in a future climate Landslide hazard in Europe

SafeLand, Jaedicke et al., 2013

Landslide hazard and risk in Norway

-Snow avalanches -Rock slope failures -Water-triggered landslides Deaths Landslide types -Quick clay slides Distribution of deaths due to slides 1900-2010

Sogn og Fjordane 1900 Nordland Troms 1910 Møre og Romsdal 1920 Hordaland Finnmark 1930 Oppland Sør-Trøndelag 1940 Telemark Vest-Agder 1950 Nord-Trøndelag Rogaland 1960 Buskerud Snøskred 1970 Oslo Snøskred Steinskred Aust-Agder 1980 Steinskred Ø stfold Løsmasseskred Løsmasseskred Hedmark 1990 Undervannsskred Undervannsskred Vestfold Isnedfall Isnedfall Akershus 2000

0 50 100 150 200 0 50 100 150 Antall drepte i skred per fylke 1900-2010 Antall drepte i skred per tiår 1900-2010

Landslide types

Snow avalanche (not discussed more) Rock slides/falls Water-triggered slides (Debris flows/slides) Quick clay slides Rock slides 175 fatalities in 3 large accidents, 1905, 1934, 1936.

Fatalities caused by the tsunamis, not the rockslide itself.

Many large unstable rock slopes in Norway, only few are monitored.

Unstable rock slopes in Norway • Troms: 117 unstable slopes • Sogn & Fjordane: 23 unstable slopes • Møre & Romsdal: 22 unstable slopes Fallnesfjellet, Skibotn. I. Henderson, NGU • Much of the country still not mapped. • Many unstable slopes are periodically monitored, but only few are continuously monitored. Kassen ved • NGU and ‘Åknes-Tafjord Bandak. Beredskap’ (NVE) play R. Hermanns, NGU important roles in mapping and monitoring Cont. monitored Åknes, mountains 2015 Volume ca. 50 mill m3 Movement 2- 15cm/year

Section for rock slides, NVE

Storfjorden (Å knes) • Narrow fjord with steep hillsides • Maximum depth more than 700 m • Fjord heads in the inner part of the fjord are the most critical locations – Largest amplification – Most people live here • In summer thousands of tourists • Arrival times after slide release – Hellesylt, 4-5 min – Geiranger, 10 min – Tafjord, 12 min New movie: ‘Bølgen’ (The Wave), released September 2015.

‘Mannen’ The “Veslemannen” Event, fall 2014 Veslemannen Volume: 120 000 – 180 000 m3

From L.H.Blikra, NVE Inverse velocity – timing of landslide

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0.5 Press conference 15:00, 28 October

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0 27/10/14 0:0027/10/14 12:0028/10/14 0:0028/10/14 12:0029/10/14 0:0029/10/14 12:0030/10/14 0:00 From L.H.Blikra, NVE

October 29: Less precipitation than forecast, colder weather with snow. Reduced velocity.

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0 27/10/14 0:0027/10/14 12:0028/10/14 0:0028/10/14 12:0029/10/14 0:0029/10/14 12:0030/10/14 0:00 From L.H.Blikra, NVE Water-triggered slides

Ca. 125 fatalities in debris flows / slides last 150 years

Debris slide, City of Bergen 2005 • Landslide caused by heavy rain (and human activity). • 4 Fatalities • After 2005, City of Bergen hired 3-4 geologists. • Started program of regional suceptibility mapping. • Followed up with detailed mapping of all ”hot” areas. • Based on the mapping, starts program of mitigation to secure dangerous areas. Notodden station, July 2011, excess surface water due to blocked drainage

Quick clay slides

•Large populations live in quick clay areas •Last 100 years mainly released by human activity •River and stream erosion is also important •Rare, large events with potentially large consequences. •150 fatalities last 150 years Rissa slide 1978

Climate changes

Annual precipitation

Annual precipitation in Norway, 1900-2013 (% of ”normal” (1961-1990)) Expected change next 100 years: Continued increase, and increase in number and intensity of ”extreme events” NB! Large regional variation and uncertainties. Klima 2100

Report launched in September 2015. Describes past climate, and prospects coming climate changes, and effects. Updated down-scaling of IPCC AR5 report.

Demograhic changes (SafeLand) Landslide risk management

Mapping Building codes Detailed hazard and risk analyses for building purposes Risk mitigation measures

Managing risk: Mapping of hazards

Different levels and scales • National level; Susceptibility maps (1:50 000). Do not include probability. Covers whole country. • Municipality level: Overall land use planning (1:5000 – 1:20 000). Includes probability according to P & B act. • Detailed land use planning: 1:5000. Includes probability according to P & B act. • Individual buildings: 1:1000. Includes probability according to P & B act. What are the hazard maps used for?

Identify the extent of slide and avalanche problems for a municipality Plan new areas for buildings and other infrastructure ─ Ensure safe localisation In critical situations (e.g. in periods of extreme precipitation) ─ Safe areas ─ Which houses are safe? ─ To where, locally, can people be evacuated. Prioritizing of mitigation measures ─ Risk assessment ─ Which houses need mitigation first?

Mitigation strategies for geohazards; Risk reducing measures.

1. Good land use planning! 2. Proper and enforced building codes and good construction practice. 3. Construction of physical mitigation measures, such as dams, and barriers, catching nets, terrain modifications, etc. 4. Establishment of early warning systems 5. Establishment and maintenance of network of escape routes, safe places, etc. 6. Ensure public awareness and a community preparedness; build up competence regionally and locally. 7. Build up and maintain a functioning society; health, education, communication, transport, rescue and relief, etc., etc. Physical mitigation measures Purpose: • To prevent slide release • Stop landslides or lead them into areas where they do less or no damage • Design and construct buildings to withstand slide forces. • Move buildings (planned or existing) to safer places.

Mitigation measures; sometimes massive! Preventing rock fall or rock slide release

Dams for rockfall and debris slides Catching dam

“Plough dam” Dam with energy absorbing material for rock fall.

Levees for snow avalanches and debris slides

Received snow avalanches 6 times last winter. Debris flow protection along creeks and ravines

With sedimentation basins

Quick clay mitigation; engineering solutions (support constructions and geometry changes)

Anchored retaining wall

Quick clay

These are measures which the Bedrock municipality may enforce to allow building. The stability must be improved, and the Relief - counterfill engineer defines the best measure.

Quick clay Monitoring systems, Å kneset:

Surface movements(InSAR, tensiometers, Radar) Deformations in boreholes Pore pressure / water table Seismic activity, Weather station, Total stations. Lasers, etc.

Early warning centre: in operation 24 / 7

Alarm tresholds criteria based on: • Total displacements • Velocity in defined time periods • Acceleration • Treshold values need to be defined and updated

• Sirens in all the villages located in the tsunami hazard zone • Phone messages • Evacuation procedures and routes • The police is responsible for the evacuation RESEARCH ACTIVITIES – INTERNATIONAL CENTRE for GEOHAZARDS

A Norwegian Centre of Excellence established in 2003 by the Reseach Council of Norway

10 years duration

Budget : ~ NOK 20 – 25 mill. / year (including in-kind contribution of partners, Contribution from Research Council of Norway = NOK 12 mill. / year)

Research activities (Norway) Project Duration Coordinator Partners Funding/Budget Research topic Climate and 2007- The Norwegian NPRA and more than 10 NPRA Effect of climate Transport 2013 Public Roads Norwegian institutions. change on the road and Administration rail network. (NPRA)

GeoExtreme 2005- ICG/NGU/ Bjerknes Centre, NRC/1 mill EUR Relationships between

2008 NGI Norwegian Meteorological climate scenarios and landslides in

Institute (met.no), Centre for Norway, assessment of social-

International and economic consequences of future

Environmental Research landslide. (CICERO) InfraRisk 2010- ICG/NGI Met.no, CICERO, The Institute of NRC/1 mill. EUR Impact of extreme

2013 Transport Economics (TØ I), National weather events on

Emergency Planning College (NUSB), Norwegian infrastructure.

The Norwegian Rail Administration

(JBV), NPRA Natural 2012- NPRA NVE, JBV NIFS/5.5 mill EUR Reduce vulnerability hazards – infra- 2015 and prevent accidents structure for and injuries caused by floods and slides landslides, avalanches (NIFS) and floods. Klima2050 2015- SINTEF SINTEF, NTNU, NGI, NRC/25 mill EUR Climate related risks 2022 MetNo, BI + state and private on buildings and partners infrastuctures Research activities (EU)

Project Duration Coordinator Partners Funding/Budget Research topic SafeLand 2009- ICG/NGI 27 European EC FP7/ Landslide risk 2012 organisations (universities, 8.8 mill EUR assessment and national geological surveys, management in Europe a private institutions) changing climate and demographic perspective. Matrix 2010- GFZ NGI, and 11 other EC FP7/4 mill EUR Multihazard risk 2013 (Germany) European organisations assessment. Intact 2014- TNO NGI, and 11 other EC FP7/3.5 mill Natural hazards and 2017 (Netherlands) European organisations EUR critical infrastructure.

RCN: Center for Research Based Innovation: ‘Klima 2050’

• Risk reduction through climate adaptation of buildings and infrastructure

• 5 scientific partners, 15 industry partners. Lead by SINTEF • 8 years; 2015-2023 • Total budget NOK 221 mill. WP3 on landslides – Knowledge gaps to be filled by Klima 2050 Consistent and verifiable procedures for mapping landslide risk at local or regional scale Accurate methods for the vulnerability assessment of critical infrastructure (incl. multi- and cascading hazards) Reliable local/regional early warning systems Reliable geomechanical models Environmentally friendly methods for slope stabilization Cost-effective and sustainable methods for protection works Relevant procedures for managing landslide risk at various levels (national, county, municipality)

Regulation and policy issues - actors

The Norwegian Water Resources and Energy Directorate (NVE) The Norwegian Directorate of Civil Protection (DSB) Municipalities, counties Road and railway authorities (SVV, JBV) Private consultants Regulation and policy issues - activities

Legal framework Mapping Land use planning Protection measures Warnings

National legislation concerning natural hazards in Norway Planning- and building act ─ § 25: Coverage: ─ Building areas ─ Agricultural areas ─ Public traffic areas ─ Hazard areas: …areas that because of potential for avalanches, slides or flooding, or other specific danger, are not allowed to be developed, or can only be developed under special conditions concerning safety ─ §68: Building ground. Environmental conditions ─ An area can only be built upon if there is sufficient safety against danger or considerable disadvantage because of natural- or environmental conditions.The municipality may forbid building, or put forward special requirements for the use of areas mentioned above. The Plan and Building Act

LandslideSlide Definition of acceptable Annual hazard for buildings probability with different functions (Return period) 10-2 (1/100) Based on probability

For new buildings, after 10-3 1985. Most buildings (1/1000) are older! 2 x 10-4 (1/5000)

Organization and responsibility The municipality: Responsible for ensuring that all necessary investigations have been carried out prior to any building or other development. Responsible for reinforcement of the Planning and Building Act.

The County administration: Can stop building projects, even if approved by the municipality.

The government: Directorate for Water and Energy (Ministry of Energy): Responsibility for making plans and priorities for hazard and risk mapping, establishment of mitigation measures, landslide and avalanche warning, etc. Provides funding for mapping and mitigation.

Directorate for Civil Protection and Emergency Planning: Responsible for preparedness and safety at all levels. Natural hazards recently included. Excercises. Crisis preparednes – four principles (DSB)

Subsidiarity: Lowest possible organisation level, i.e. municipality. Similarity: Organisation as during normal circumstances. Responsibility: Organisation responsible under normal circumstances also responsible during a crisis. Cooperation: Authorities, agencies and other stakeholders must seek cooperation with each other.

Crisis preparedness

Emergency preparedness Regional warnings (run by NVE) Early warning large rockslides (run by NVE) Test scenarios (quick clay slides, large rock slides) Summary and conclusions

• Norway has frequent problems related to natural hazards, causing economic loss and loss of lives. • National legislations provide the necessary instruments to prevent much damage. The problem is that they are not always followed. • The planning and building act, if used properly, is efficient, but many houses were already built in hazardous terrain before the law appeared. • Hazard (and risk) mapping is an important tool in all municipalities, and are important for land use planning, preparedness for acute situations, design of infrastructure, etc. • Physical mitigation measures are important but not always sufficiently prioritized. They are expensive, and unfortunately it is often easier to get funds for mitigation after an accident has happened! • Large tsunamigenic rock slides are the biggest potential catastrophes in Norway. Mitigation measures for these are mostly monitoring and early warning. • Public awareness and a community preparedness, as well as competence at all levels (individual, local, regional, national) are perhaps the most important and effective measures!

Thank you for your attention!