Flood Risk and Vulnerability Analysis Project - Atlantic Climate ...

Watershed boundaries were created by referencing the drainage network and watershed
topography. Only areas upstream of the community were included. This was further
interpreted as areas upstream of the downstream limit of the existing flood plain
mapping.
The watersheds were digitized as polygons.
Where watershed lines were coincident, the lines were digitized as the same line and
copied to the other appropriate layer(s).
Watersheds along shorelines of waterbodies and/or coastlines did NOT use these
features as the edges of polygons as shorelines and coastlines are prone to significant
changes in water features.
Feature codes are compliant with those defined in Feature Codes – Flood Risk Mapping
document provided by WRMD.
The geo-referenced digital map layers for the watersheds are provided, as a deliverable
of this project, as ESRI Shapefiles and as AutoCAD R2000 DWG Files. All digital files
are provided in provincial MTM projections (NAD83).
3.3 C3 - Land Cover Classification
3.3.1 Introduction
To support flood risk assessment, a land cover classification was conducted in 39 community
flood watersheds across the island of Newfoundland in Labrador, Canada. Seven (7) land cover
classes (excluding an eight “unclassified” class comprised of ice, clouds and shadows) were
classified from 10-meter resolution, 4-band multispectral SPOT imagery captured between 2005
and 2010. Additionally, two (2) land cover change classes, deforested areas due to
development and other deforested areas were derived from Earth Observation for Sustainable
Development of Forests (EOSD) data which was generated from 30-meter Landsat satellite
imagery from the year 2000. The resulting nine (9) classes of land cover represent both time
periods and were summarized for each of the 39 watersheds. The data was used as an input to
hydrologic models described in the main body of this report. This section documents the
imagery and data sources provided to AMEC, the imagery classification methods, the results,
and provides recommendations for future similar studies.
3.3.2 Imagery and Data Sources
The inputs to the land cover classification were 2010 SPOT satellite imagery, 2000 EOSD data,
and ancillary GIS data such as watershed and municipal boundaries. Approximately 90% of the
watersheds were in UTM Zone 21, but the eastern watersheds are in Zone 22. Vector data was
provided in the MTM projection and was reprojected to matching UTM zones from respective
SPOT images.
TA1112733
34