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

parameters were deemed 1 st order parameters. On the other hand, some parameters, such as
watershed deforestation or dominant soil hydrologic soil class, attempt to quantify the potential
for community flood risk. This concept is important to consider in applying the parameters in the
prioritization process. These parameters were deemed 2 nd order parameters.
The application of the prioritized data and methods developed for this project yields the ranking
of communities provided in the report; for communities with flood plain mapping presently and
for communities without flood plain mapping presently.
Assessing Need for Flood Forecasting / Flood Warning System
The objective of this task was to identify communities vulnerable to flooding that should be
considered for flood forecasting and/or flood warning systems. The task was completed through
a review of historical flood observations (i.e., the Flood Events Inventory) and existing flood
hazard and risk maps, combined with ancillary data on precipitation, topography, lifelines
(roads, bridges, etc.), and with census information on population densities, types, and fluxes.
The methodology used for this study generally consisted of identifying vulnerable communities
and subsequently assessing their susceptibility to direct and indirect effects of flooding. First,
potentially vulnerable communities were identified by reviewing the event frequency and
damage estimates contained in the updated Flood Events Inventory. After communities were
identified, the physical hazard for each community was assessed. The next step was to
determine each community‟s vulnerability to the direct effects of flooding (e.g., inundation).
Third, potential indirect effects, such as isolation, were assessed for each of the identified
communities. Finally, the results of each of the above steps are summarised in a decision
matrix, highlighting those communities most vulnerable to flooding.
The results of this assessment indicate that the communities that should receive the highest
priority for flood forecasting and warning systems include Corner Brook, Marystown, Placentia,
Codroy Valley, St. John‟s, Deer Lake and Stephenville. Corner Brook, St. John‟s, and
Stephenville are major population centers. Deer Lake is located in the Humber River
Watershed, and already has WRMD provided forecasting in place. Placentia and Marystown
are both located on the coast of Placentia Bay. These two towns, along with St. John‟s, Codroy,
and Stephenville are communities lying directly in hurricane storm tracks.
Those communities representing a medium priority include Badger, Belleoram, Carbonear,
Gander, Grand Bank, Hermitage-Sandyville, King‟s Point, Middle Arm, Mount Pearl, Rocky
Harbour, Rushoon, and Steady Brook. Some of these fall within the same watersheds as
communities included in the high priority grouping. Mount Pearl is located in the same
watershed as St. John‟s, while Steady Brook is located in the Humber River Watershed. A
number of these communities (Hermitage-Sandyville, Grand Bank, Belleoram, Rushoon, Middle
Arm, and Carbonear) were in the direct path of past hurricane tracks. Rocky Harbour may be
vulnerable to those storms tracking west of the island. Badger lies in the Exploits River
TA1112733
vii