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Case Study:
An Earth Observation Disaster Management System
to Monitor the Effects of the 1997 El Niņo in Peru

GeoSolutions Consulting provides expertise in the development of systems designed to aid the monitoring and management of the effects of natural disasters. The 1997/98 El Niņo weather event caused record levels of precipitation in many parts of the world, including Peru. The precipitation in Peru led to flooding along rivers, which resulted in the displacement of thousands of citizens. As a secondary consequence, the saturated hillsides became susceptible to landslides, which resulted in further losses of property and life.

Objectives:

The objective of this demonstration project was to evaluate geomatics technology as a management tool for risk management and natural hazard mitigation. Custom mapping enabled emergency response planning for two areas of Peru. As well as planning tools, the maps categorized risk for El Niņo related disasters. The success of this project demonstrated the essential role of Canadian geomatics and earth observation technology in disaster relief efforts.

Data Used:

  • Remotely Sensed Data - RADARSAT, LandSAT and IRS. Flood extents and DEMs were derived from RADARSAT scenes, collected during peak and post-flood periods. Classification of multispectral LANDSAT imagery provided land cover data for the Tumbes study area, and an IRS MSS scene was used to provide similar data for the Puno study area.
  • DEM - A DEM for the northern site (Tumbes) was generated from the topographic contour data. DEMs for the Puno site, were generated from RADARSAT data.
  • Statistical Data - Tables of data provided by INEI (Instituto Nacional De Estadistica E Informatica) were joined to corresponding geographic areas to build GIS coverages.
  • 1:100,000 Scale Base Mapping - Existing paper topographic maps were converted to digital format and entered into the GIS.

 


LandSAT 5TM Bands 7,5,3 October 6, 1997
RADARSAT image February 10, 1998

Work Flow:

  • Using base, statistical and other data, acquired from various sources, a SPANS GIS database was created.
  • The Remotely Sensed data was geographically referenced using PCI image registration tools.
  • A Digital Elevation Model (DEM) was derived for each of the study areas. From these DEMs, slope and aspect maps were created.
  • IRS and LandSAT images were classified and interpreted for each study area and integrated into the GIS.
  • GIS modelling techniques, based on geology, vegetation, bio-climactic, slope and aspect data produced a Landslide Hazard Prediction Map for the Puno study area.
  • In the Tumbes study area, a map of flood extents for February 1998 was defined using a combination of methods. The first step in the process was to use the LANDSAT image from October 1997, to digitize the Tumbes river boundary. The second step consisted of overlaying the February 1998 RADARSAT image on the DEM to digitize the flood extent boundary. To resolve any ambiguous zones of suspected flooding, another RADARSAT image from March 1998 was employed; this indicated whether the area was in a natural state of high-water or in a flood situation. The DEM was used to aid in the interpretation of the RADARSAT image in determining the flood extents.
IRS 1C LISS-3, Bands 4,3,2, April 17, 1998 with Base Data(Puno Study Area)

Flood Extent Mapping with Base Data and LandSAT image as background (Tumbes Study Area)

Overall Risk Map (Tumbes Study Area)

Overall Risk Map (Puno Study Area)

  • GeoSolutions Consulting Inc. modelled and presented various risk maps to demonstrate probable impacts of flood-related hazards. Risk maps were developed using varying methodologies and by combining different data sources: such as statistical data, interpretation of satellite data and topographic data.
  • Risk maps were developed to show: Risk of Flood Related Landslides To Transportation Networks (Tumbes), Risk of Landslides To Transportation Networks (Puno), Risk To Roads, Bridges And Railways, Risk by Landuse Classification, Risk by Population Density, Risk to Services, Risk to Structures and Overall Risk.
  • These maps were prepared for publication and presentation using PCI's ACE software.


Risk of Flood Related Landslides To Transportation Networks Overlayed with Flood Extents and LandSAT image

Visit an interactive web site, developed by PCI and hosted by NASA, that shows the Risk Maps (modelled by GeoSolutions) along with satellite imagery used in this project.

Click here to visit then Click on the link to the Peru El Niņo Application page to view the application.