Experience and Lessons Learned in utilizing geo-referenced - PDF document

Experience and Lessons Learned in utilizing geo-referenced information in DRM Country Presentation Sri Lanka Kumari M . Weerasinghe Senior Scientist National Building Research Organisation Sri Lanka

§ Floods NATURAL HAZARDS IN SRILANKA § Landslides and mass movement s § Drought § Cyclones § Coastal erosion § Subsidence and erosion § Ground settlements § Tsunami § Earthquake Geo-referenced information are utilized in various ways for disaster Risk reduction and sustainable development in the country • Studying the distribution of landslide potential in the central highlands of Sri Lanka and landslide hazard zonation mapping • Identify the areas subjected to flooding and preparation of flood inundation maps • Study and map the areas subjected to – costal erosion – Sea level rise – Tsunami inundation • Predict and map the areas subjected to agricultural drought • M apping cyclone paths and areas subjected to wind hazard • and many more

Among the International Cooperation received over the years… • Sri Lanka was selected as a Pilot Country for implementation of the 5 year Action Plan (2012-2017) formulated by the UNESCAP for developing the capacity of the countries in the region to use space technology applications for Sustainable Development and Disaster Risk Reduction. • Sri Lanka was also selected as one of the first two pilot countries to implement the UNESCAP project on Regional Cooperative M echanism for Drought M onitoring and Early Warning . As a result, S ri Lanka was able to participate in various capacity building programmes organized under the blessings of UNESCAP • Use of M ulti GNSS information in Disaster Risk Reduction, held in Bangkok, Thailand 2012 • Sub-regional training on “ Development of geo referenced information system for disaster risk management held in Dehradun, India from 26 th – 29 th August, 2013 • Capacity building programme on space technology and GIS application for disaster risk reduction, held in Seoul, Korea from 28th October to 17th November, 2013.

Availability of geo-referenced information • National hazard profile (www.hazard.lk) • National Risk profile (www.riskinfo.gov.lk) • Landslide hazard zonation maps (www.nbro.gov.lk) Cabinet decision has been taken for Development of National Spatial Data sharing Infrastructure (NSDI) The thematic areas of Disaster M anagement and Environmental M anagement are selected for the pilot project Drafting the spatial data infrastructure road map for the thematic area DM was commenced in mid M ay, 2014 and is expected to be completed by the end of July 2014. Testing the road map as a model, fine-tuning it, and using as a basis for building the NSDI will be implemented subsequently. Visualizing NSDI SLS DI is viewed as the technology, policies, standards, human resources and related activities necessary to collaborate, acquire, process, distribute, use, maintain and preserve spatial data throughout all levels of government, private and and citizens for efficient service delivery

Steps towards a National SDI Utilizing geo-referenced information on landslides disaster risk reduction and Experience and Lessons Learned

In the past majority of landslides occurred due to natural causes In 1986, a comprehensive study on landslides was implemented by the government In 1990, 5 year long Landslide Hazard Zonation M apping project was implemented with the technical and financial support of UNDP for Identification of landslide potential and landslide disaster risk reduction At the inception, M aps were intended to be used as a tool for development planning

Preparation of Landslide Hazard zonation maps Field Digitizing of Statistical analysis (Aerial Photo / ABMP Transferring to evaluate and maps and geology maps) verification data to base attribute assign weights maps and maps • Landslide distribution map additional • Engineering Geological map data • Hydrology map Integration of collection • Material distribution map (overburden deposits) weighted maps and • Geomorphological map preparation of (landform map) hazard zonation • Landuse and management map Calibration with map actual landslide map and field checking Research on further Preliminary hazard zonation improvements map • zonation techniques • integration of run-out zone of landslides Cartographic • Map presentation methods preparation • Data base developments Final Landslide Hazard Final Landslide Hazard Zonation M ap Zonation M ap www.nbro.gov.lk

Recommended Land Use Practices for Different Landslide Hazard Zones Landslides not likely to occur (expect for flood plains) Landslides can be expected Landslides most likely to occur

Degree of Reliability of Predicted Landslide Hazard 1:50000 scale maps are published in www.nbro.gov.lk 1:10000 scale maps are issued on request M aps are being utilized by both government and private sector organizations for disaster impact assessments and development planning Accuracy levels were considered as sufficient for originally intended use of the hazard maps RESEARCH ON APPLICATION OF DETERMINISTIC SLOPE STABILITY EVALUATION TOOL - SINMAP Output of the participation in Mini Project 2006/ 2007 at AIT

Total Statistics Moderately Quasi Lower Upper Stable Defended Total Stable Stable Threshold Threshold Area (km 2 ) 89.30 10.20 13.50 28.30 9.60 2.00 153.70 % Area 58.10% 6.64% 8.78% 18.41% 6.25% 1.30% 100.00% No of Landslides 6 0 2 8 7 6 29 % Landslides 20.69% 0.00% 6.90% 27.59% 24.14% 20.69% 100.00% Landslide Density 0.07 0.00 0.15 0.28 0.73 3.00 0.19 Predicted reliability 72.41% Indicate instability Indicate marginal instability Issues while utilizing landslide hazard zonation maps for development planning • High hazardous zones are already occupied • Growth of population • Availability of suitable land is limited for relocation and also for future development • Sociological and political issues related to relocation

Based on the lessons learned, national approach on landslides disaster risk reduction has been reformulated landslide early warning Structural and/or non structural Mitigation of landslide risk Awareness among communities on living with landslides Landslide hazard zonation mapping EW Model NBRO DOM Landslide early warning message is issued by NBRO EW is disseminated through DMC and Media Step 1 - Issuance of Landslide early warning at national level

National level landslide warning is issued at three levels Approximate rainfall threshold values Landslide watch 75 mm/ day Landslide Alert 100mm/ day Be Prepared for 75 mm/ hour or 120mm/ day Evacuation

Increasing trend of manmade landslides

Step 2 - Government’s intervention by enactment of new regulation in the year 2011 Builder Implement const ruction by landslide adhering t o the sit e specific early warning recommendations and guidelines Government’s Structural and/or non structural regulation Obtaining landslide clearance prior to Mitigation of landslide risk approval of all construction in landslide prone areas Awareness among communities on NBRO living with landslides Performing site specific investigations Identification of landslide hazard potential Landslide hazard zonation mapping With the new regulation, demand for landslide hazard maps was increased General public also started to utilize the maps Problems were faced in interpretation of hazard potential by the non technical map users 1. Resolution of the map (presently available at 10 m and 50 m accuracy ) was not sufficient in borderline cases 2. Difficulty in demarcating hazard zonal boundaries on the actual ground, if printed maps are used 3. Lack of access to and/ or knowledge in using GIS software for using the maps in digital form 4. Inabilit y to identify t he possible adverse impacts due to hazard potentials in upslope areas 5. Lack of t echnical knowledge to ident ify the threats due to active and/or dormant landslides locat ed in the upper slopes 6. Overlooking the increase in t he severity of hazard potential due to haphazard ground modifications

Problems were faced in interpretation of hazard potential by the non technical map users contd… Even w hen the maps are used in digital form, misinterpretations occur when boundaries of several hazard zones cross a plot of land Example: Land parcel A – Belongs to a single hazard zone represented by the color yellow. Land parcel B – Belongs to two hazard zones interpreted by colors orange and yellow Land parcel C – Belongs to four hazard zones interpreted by colors green, yellow , orange and red In the case of land parcels B and C hazard potential may possibly be interpreted to the advantage of the user. A Web based tool was developed and proposed as a solution to minimize misinterpretation of hazard maps.

Information from the landslide hazard zonation maps, map of slope angle ranges, map of sub catchments and past landslides were considered . User Select ion of District Select ion of Admin Division Select ion of Grama Niladhari Division Select ion of Land Parcel Number