History of Flood and Low Flow Events and Solutions Implemented

In the face of current and future climate change, various adaptation measures are necessary. These will need to be implemented through a variety of means including new ways of doing things; standards and laws (construction, land use planning, urban planning, environment, infrastructure, urban technical networks, etc.); the establishment of adaptation plans and actions at various levels (municipal, regional county municipality, watershed); and changes in warning systems.

However, before taking any such actions, it would be useful to know, analyze and understand the consequences of past and present events, as well as their links with associated weather conditions. To date, this information has not been compiled in a systematic and uniform manner by communities affected by these phenomena, not has it been centralized. This makes it difficult to establish regional profiles that indicate the potential vulnerabilities associated with climate change.

Build a database of flooding and low flow events for watersheds in a pilot area (south of the St. Lawrence River between Montréal and Lévis), including their impacts at different scales and associated weather phenomena.

• Identify needs and data sought by different users;

• Gather data from archives;

• Create the database (DB) and enter the data;

• Analyze the data, establish the first regional profiles of local sensitivities;

• Operationalize the DB and have it tested by some fifty users;

• Disseminate the information.

The project arose from requests made by several adaptation stakeholders (municipalities, provincial and federal ministries and departments) who, faced with the need to produce (or assist in the production of) local vulnerability profiles and to carry out risk analyses as part of adaptation plans, had few means at their disposal to go back in time and provide a history of natural disasters. Inspired by good practices such as the French national historical flood database (Base de Données Historiques sur les Inondations or BDHI), the work began with an inventory of data sources.

The development and validation of the database architecture in collaboration with multiple partners and potential users allowed its relevance to be confirmed. The final phase of this pilot project was the testing of the DB by a variety of stakeholders, an essential step that made it possible to precisely identify the positive and negative features of the DB and any issues to be addressed. The other advantage of the testing phase was that it showed the extent to which the list of fields of interest is extremely representative of the potential of such a database and of the expectations of future users, thereby confirming the relevance of AQUARISC.

AQUARISC makes it possible to produce a historical timeline of past events (Figure 1). Close to 2,000 floods and a hundred low flows occurring between 1642 and the present day were documented. In addition, the geolocation feature offers the advantage of identifying vulnerable areas that were the most affected by the listed events (Figure 2) and providing direct access to the data concerning these events.

Figure 1 : Timeline showing examples of events and anti-flood/low flow initiatives since the 17th century.

Figure 2 : Number of floods recorded in the study area from 1642 to 2016. All municipalities affected by flooding leading to significant damage are shown in blue. The darker the shade of blue, the greater the number of flood events experienced by the municipality.

One concrete application of the database is the production of event summary reports. These are automatically generated following a query, and cover all relevant data recorded in the database. This makes it possible to learn everything about event X at a given time Y. In addition to the ability to perform a variety of analyses, this application makes it easier to understand the interactions between weather conditions and impacts.

In the end, AQUARISC has proved to be a unique record of flood and low flow events in Québec. It is a novel and indispensable tool for anyone interested in the analysis of vulnerabilities related to flooding and low flows and in climate change adaptation strategies that have been implemented in the past

• Bibliothèque et Archives nationales du Québec (BAnQ)

• Centre d’expertise hydrique du Québec

• Chaire de relations publiques et communication marketing (UQAM)