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

6.1.2 General Characterizations of Sub-regions
Communities within each Sub-region share important elements of each of the three linked
factors, such as elevation, soils, population, precipitation trends, and sea level rise impacts.
These similarities present common vulnerabilities and, in most cases, common solutions. Table
6-1 through Table 6-3 present generalized characteristics of each Sub-region using some of the
same priority factors developed in Task D – Assess Need for New / Updated Flood Risk
Mapping.
Specific for this section, the Priority Factors were calculated using the following methods.
Location Priority Factor is a function of the community‟s designation as a Riverine
Hazard community, its status as either coastal or riverine, and its elevation.
Communities that are classified as Coastal and lie at sea level, have a high Location
Priority Factor. Further, those communities classified as a Riverine Hazard that lie within
1,500 meters of a stream, have an even higher Location Priority Factor. As an example,
the community of Carbonear 1) is a coastal community at sea level and 2) lies
approximately within 1,500 meters of the stream (i.e., 1,148 meters). Therefore,
Carbonear has a Location Priority Factor of 2. In contrast, Brigus is also a Coastal
community but lies well above sea level (12 meters). Brigus also lies a distant 2,400
meters from the nearest stream. Taking into account both of these physical
characteristics, Brigus‟ Location Priority Factor is 0.
Soils Priority Factor is based on hydrologic soil groups. Soils with low runoff potential
ranked as “0”; soils with high runoff potential ranked as “4”. Soils data references the
Soil Survey Reports for Newfoundland and Labrador available from Agriculture and Agri-
Food Canada 28 . Detailed explanation of data fields is also provided through this website.
Slope Priority Factor is based on average slope of the watershed with “0” for slopes less
than or equal to 5%; “1” for slopes greater than 5% and less than or equal to 15%; and
“2” for slopes greater than 15%.
Drainage Density Priority Factors is a function of the drainage densities (linear distance
of streams divided by land area) where the density value equal to or less than the
average of 0.26 km/square km were assigned a priority factor of “0” and those above
that average were assigned “1”.
Then, within each Sub-region, an average was found for each individual Priority Factor. The
results shown on Table 6-1 are averages of all individual communities‟ priority factors within
each Sub-region. For example, the 12 communities categorized into the West-CB Sub-region all
had their own Location Priority Factor. GIS analysis quantified the status of each of the 12
28 http://sis.agr.gc.ca/cansis/publications/surveys/nf/index.html
TA1112733 page 134