Economic evaluation of the potential impacts of the erosion of Quebec’s maritime coasts in a context of climate change
Research report submitted to Ouranos
Under the direction of
Pascal Bernatchez, Ph.D.
May 2015
PRODUCTION TEAM
Management and research Pascal Bernatchez, Ph. D. Coastal geomorphology and remote sensing Project manager Professor and Chairholder, Research Chair in Coastal Geoscience Laboratoire de dynamique et de gestion intégrée des zones côtières (LDGIZC) (coastal zone dynamics and integrated management laboratory) Biology, chemistry and geography department Université du Québec à Rimouski (UQAR) Email: [email protected]
Research team Steeve Dugas, B.Sc., Research Professional, LDGIZC, UQAR Data processing and analysis, geomatics, writing Christian Fraser, M.Sc., Research Professional, LDGIZC, UQAR Data analysis, writing Laurent Da Silva, M. Sc., Economist, Ouranos Economic research, processing and analysis and writing Maude Corriveau, M.Sc., Research Professional, LDGIZC, UQAR Data processing and validation Nicolas Marion, B.Sc. student, UQAR Data processing (transfer of assessment roll parcels) Mia Charette, B.Sc. student, UQAR Data processing (Transfer of assessment roll parcels) Tessa Parisé, B.Sc. student, UQAR Data processing (Transfer of assessment roll parcels) Caroline Côté, Master’s degree (DESS) student, UQAR Data processing (Transfer of parcels identifying railways)
Collaborators François Morneau, M. Sc., Scientific Coordinator, Ouranos Manon Circé, M. A., Senior Economist, Ouranos Xavier Mercier, M. Sc., Economist, Ouranos Claude Desjarlais, M. Sc., Senior Economist, Consultant, Ouranos Ursule Boyer-Villemaire, M. Sc., Oceanographer, Consultant, Ouranos Susan Drejza, M. Sc., Research Professional, LDGIZC, UQAR
Complete reference Bernatchez, P., Dugas, S., Fraser, C. and Da Silva, L. (2015). Economic evaluation of the potential impacts of the erosion of Quebec’s maritime coast in a context of climate change. Coastal Zone Dynamics and Integrated Management Laboratory, Université du Québec à Rimouski. Report submitted to Ouranos, 45 p. and appendixes.
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ACKNOWLEDGEMENTS
This study was undertaken with the financial support of Natural Resources Canada, the Green Fund under the 2013-2020 Climate Change Action Plan and Ouranos. We would like to thank the ministère des Affaires municipales et de l’Occupation du territoire du Québec (MAMOT) (Quebec Municipal Affairs and Land Occupancy Ministry), the RCMs (Regional County Municipalities) and the municipalities for their property assessment rolls and cadastral data.
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SUMMARY
This study is the first economic assessment of the potential impact of coastal erosion on Quebec maritime infrastructures in the context of climate change, if no new adaptation measures are implemented and those already in place are not maintained. All buildings, roads and railways were identified using high-resolution mapping and they were assigned a value of exposure to erosion between now and 2065. The calculation of exposure is based on two parameters: 1) the probable rate of shoreline or coastline migration anticipated for each homogeneous geomorphological unit and 2) a safety margin that varies depending on coast characteristics.
This economic evaluation was performed in constant 2012 dollars, based on assessment rolls and costs from past projects. Thus, the value of exposed buildings was estimated from the adjusted property value for the same reference year, 2012. The property value considers the marketplace, but slightly underestimates the real value. For roads and railways, the replacement value of these infrastructures, as well as protection works, was given priority. These estimates provide a scope of potential losses and not an accurate assessment of the amounts that must be invested over the next 50 years to maintain and replace infrastructure at risk.
The area under study covers 3220 km of coastline and includes 16 regional county municipalities (RCM) spread out between the Bas-Saint-Laurent, the Côte-Nord, the Gaspésie and the Îles-de- la-Madeleine. The results of the study indicate that 5426 buildings throughout the territory will be exposed by 2065 if no adaptation measures are implemented and existing works are not maintained, keeping a safety margin of at least 5 metres from the coastline. The value of these buildings, in 2012 dollars, is $732 million. There are also 294 km of roads and 26 km of railways that will be exposed by 2065, representing a value of $776 million. The potential economic loss for the period between 2015 -2064, i.e. the next 50 years, is estimated at $1.5 billion.
In terms of buildings exposed to erosion, residential buildings will be those mainly affected, representing 83% of the value of all buildings exposed by 2065. In the Bas-Saint-Laurent administrative region, the number (41%) and value (53%) of buildings potentially exposed by 2065 are the highest in maritime Quebec. In terms of the number of buildings, the most markedly affected RCM is Manicouagan on the Côte-Nord, while the RCM of Rimouski-Neigette has the highest total value.
An overview of transport infrastructure threatened by erosion indicates that exposed municipal and local roads dominate with 154 km, closely followed by national roads with 138 km. However, the estimated cost to maintain or replace exposed national roads is much higher, i.e. 60% of the total value of transport infrastructure exposed to coastal erosion by 2065. In the Gaspésie – Îles-de-la-Madeleine administrative region, the length (54% of the coastline) and value (79% of the total) of potentially exposed transport infrastructure by 2065 are by far the highest in maritime Quebec, specifically in the RCM of La Haute-Gaspésie.
Lastly, the results of this study highlight the importance of preventive management of coastal risks that would significantly limit the costs associated with coastal erosion.
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TABLE OF CONTENTS
Production team ______ii
Acknowledgements ______iii
Summary ______iv
Table of contents ______v
List of figures ______vi
List of tables ______vii
List of appendices ______vii
1 Introduction ______1 1.1 Coastal erosion ______1 1.2 Mandate and objectives ______1 1.3 Study area ______2
2. Methodology ______3 2.1 Future coastal change scenarios ______3 2.1.1 Recent climatic and oceanographic conditions ______3 2.1.2 Coastal change patterns and delineation of homogeneous geomorphological units ______4 2.1.3 Choosing probable migration rate ______5 2.1.4 Coastal protection works ______6 2.1.5 Coasts that accumulate sediments ______9 2.2 Mapping of exposed elements ______9 2.2.1 Point data processing: buildings and land ______9 2.2.2 Linear data processing: roads and railways ______10 2.3 Calculation of exposure ______11 2.4 Safety margin ______12 2.4.1 Margin proposed for buildings ______12 2.4.2 Margin proposed for roads and railways ______12 2.5 Economic evaluation of exposed elements ______13 2.5.1 Economic evaluation principles ______13 2.5.2 Property assessment of buildings ______13 2.5.3 Value of replacing or moving roads and railways ______14 2.5.4 Property assessment of developed and undeveloped land ______18 3. Overview of the exposure of buildings, roads and railways in maritime Quebec __ 19 3.1 General overview ______19
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3.2 Buildings ______21 3.3 Roads and railways ______30 3.4 Discussion on the exposure of roads ______36
5. Conclusion ______38
References ______39
LIST OF FIGURES
Figure 1. Location of the study area ______2 Figure 2. Equation used to calculate the exposure of buildings, land and transport infrastructure to coastal erosion (modified from Fraser et al., 2014a, b, c; Drejza et al., 2014a, b) ______11 Figure 3. Spatial distribution of costs related to the exposure of buildings, land areas and transport infrastructure in maritime Quebec by 2065 ______20 Figure 4. Number of buildings exposed to coastal erosion by 2065 in maritime Quebec, with and without safety margins ______21 Figure 5. Value of buildings (land included) exposed to coastal erosion by 2065 in maritime Quebec, with and without safety margins ______21 Figure 6. Number of buildings exposed by 2025, 2045 and 2065 for maritime Quebec, with and without safety margins ______22 Figure 7. Value of buildings (land included) in 2025, 2045 and 2065 for maritime Quebec, with and without safety margins ______22 Figure 8. Number of buildings exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins ______23 Figure 9. Value of buildings exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins ______23 Figure 10. Number of buildings exposed (land included) in 2025, 2045 and 2065 by administrative region, including the safety margin ______24 Figure 11. Value of buildings exposed (land included) in 2025, 2045 and 2065 by administrative region, including the safety margin ______24 Figure 12. Number and value of buildings (land included) exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins ______27 Figure 13. Number of buildings exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins ______28 Figure 14. Value of buildings (land included) exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins ______28 Figure 15. Value of buildings (land included) exposed to coastal erosion by 2065 including the safety margin, in maritime Quebec ______29 Figure 16. Length of roads and railways exposed to coastal erosion by 2065 for maritime Quebec, with and without safety margins ______30 Figure 17. Estimated cost of roads and railways exposed to coastal erosion by 2065 for maritime Quebec, with and without safety margins ______30
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Figure 18. Length of roads and railways exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins ______31 Figure 19. Estimated cost of roads and railways exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins ______31 Figure 20. Length and estimated cost of roads and railways exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins ______33 Figure 21. Length of roads and railways exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins ______34 Figure 22. Estimated cost of roads and railways exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins ______34 Figure 23. Overview of the exposure of roads and railways by 2065 including the safety margin, for each RCM in maritime Quebec ______35
LIST OF TABLES
Table 1. Data available to establish coastal change scenarios, Côte-Nord* ______7 Table 2. Data available to establish coastal change scenarios, Bas-Saint-Laurent, Gaspésie and Îles-de-la- Madeleine* ______8 Table 3. Building classes ______10 Table 4. Classes of linear infrastructure ______10 Table 5. Safety margins width ______12 Table 6. Average replacement cost in 2012 dollars (CAN) per metre by type of infrastructure and by municipality ______16 Table 7. Examples of unit costs for linear infrastructure and coastal protection works ______17 Table 8. Overall picture of the exposure of buildings, undeveloped land and transport infrastructure in maritime Quebec by 2065 with and without safety margins ______20 Table 9. Comparison of the results of this study on the exposure of national highways with the study by Drejza et al. (2014) ______36
LIST OF APPENDICES
Appendix 1. Table showing value of total discounted losses from 2015 to 2065 _ Erreur ! Signet non défini. Appendix 2. Chronological overview of building types (land included) exposed to coastal erosion by 2065 for each RCM, with and without safety margins ______45 Appendix 3. Overview of transport infrastructure exposed to coastal erosion by 2065 for each RCM, with and without safety margins ______51
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1 INTRODUCTION
1.1 Coastal erosion
Recent scientific literature confirms the importance of climate change-related coastal erosion and the vulnerability of coastal communities throughout the planet (IPCC, 2013; Dalrymple, 2012; USGS, 2012; Moser et al., 2012; Marchand, 2010; Allison et al., 2009; Harvey and Nicholls, 2008; Lozano et al., 2004). Quebec’s coasts are not exempt from this trend (Drejza et al., 2014a, b; Bernatchez and Fraser, 2012; Bernatchez et al., 2008; Bernatchez and Dubois, 2004). In Quebec, coastal communities and various levels of government have always been reactive rather than proactive in dealing with this hazard. The lack of knowledge on coastal hazards and the lack of tools for development, prevention and the selection of adaptation strategies are the primary reasons given by coastal communities and land managers to explain this attitude. (Bernatchez et al., 2008; Drejza et al., 2011; Friesinger and Bernatchez, 2010). In 2006, the Government of Quebec implemented the Cadre de prévention des principaux risques naturels (Framework for the prevention of primary natural hazards), which facilitated the improvement of risk-related knowledge and the analysis and implementation of solutions (Gagné, 2013).
In recent years, several Quebec regions were surveyed and studied to assess historical shoreline change and to project future change. On the Côte-Nord, these data were used to determine initial coastal erosion risk zoning (Dubois et al., 2006; Bernatchez et al., 2012b, c, d, e). In Chaleur Bay and Îles-de-la-Madeleine, the data collected were also used to study building and infrastructure exposure to coastal erosion and the development of a coastal development planning tool (Fraser et al., 2014a, b, c). Lastly, the improved knowledge on coastal hazards helped to assess the exposure of national roads to coastal erosion and submersion in eastern Quebec (Drejza et al., 2014a, b).
However, until now, there was no overall picture of the exposure of buildings and transportation infrastructure to coastal erosion for maritime Quebec as a whole. Consequently, no assessment of the potential costs caused by shoreline erosion had been conducted to date. That being said, buildings and road and rail infrastructure have already been affected by coastal erosion in most coastal communities. This information is crucial for decision making in terms of managing coastal issues. This study thus provides an overall picture of the coastal erosion situation and the issues involved, along with short-, medium- and long-term projections.
1.2 Mandate and objectives
The mandate of the Laboratoire de dynamique et de gestion intégrée des zones côtières (LDGIZC) (Coastal Zone Dynamics and Integrated Management Laboratory) at Université du Québec à Rimouski (UQAR), in collaboration with the Ouranos team, is to perform an economic evaluation of the potential losses in buildings, undeveloped land and transport infrastructure (roads and railways) related to coastal erosion in maritime Quebec, if no new adaptation measures are implemented and existing measures are not maintained. This mandate is part of a research project on the economic assessment of climate change impacts and the cost-benefit analysis of climate change adaptation options in coastal areas in Quebec and the Atlantic provinces.
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The specific objectives of the LDGIZC mandate are:
determine the most likely coastal change scenarios by 2065 based on current knowledge surrounding coastal dynamics; determine the exposure of buildings, undeveloped land and transport infrastructure (roads and railways) to coastal erosion based on three time horizons (2025, 2045 and 2065) with and without safety margins; estimate the economic value of anticipated losses in collaboration with Ouranos.
1.3 Study area
The study area includes the administrative regions of the Côte-Nord (excluding Anticosti Island), the Bas-Saint-Laurent and Gaspésie/ Îles-de-la-Madeleine. These regions of maritime Quebec are the best documented in terms of historical and recent coastal change (Tables 1 and 2). In total, the area covers more than 3220 km of coastline and covers 16 RCMs (figure 1).
Figure 1. Location of the study area
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2. METHODOLOGY
2.1 Future coastal change scenarios To meet the first objective of determining probable coastal change scenarios, the method is based on analyzing recent climatic and oceanographic conditions, dividing the coast into homogeneous geomorphological units based on coastal change patterns, and then selecting probable migration rates for each of these units. Specifications regarding protection structures and coast that accumulate sediments are mentioned.
2.1.1 Recent climatic and oceanographic conditions
Since the late 1980s, a significant warming in average annual temperatures has been observed, especially in winter temperatures (Bernatchez et al., 2008). For example, the rise in winter temperatures for the period of 1987-2006 was 2.63°C in Sept-Îles, 2.71°C in Gaspé and 3.34°C in Îles-de-la-Madeleine (Bernatchez et al., 2008). This increase in temperatures is similar to that expected in the coming decades. For this reason, it is estimated that the speed of coastal migration during the period covering the late 1980s to today is representative of future coastal change, at least for the coming decades.
This temperature warming has different consequences on coastal dynamics, including the acceleration of cryogenic processes, reduced ice cover, increased damage associated with storms and a rise in relative sea level. First, it promotes the erosion of fine-granulated sediment cliffs through cryogenic processes (Bernatchez and Dubois, 2008; Bernatchez et al., 2011). Modeling of the frost wave and resulting erosion processes shows that the elevated retreat rates measured over the last period are expected to continue in the future, albeit without accelerating (Bernatchez et al., 2014).
Another important consequence of global warming is the reduction of ice cover in the Lower Estuary and Gulf of St. Lawrence during the winter (Senneville et al., 2014). Monitoring by the Canadian Ice Service (CIS), already shows that the percentage of ice cover for the cumulative total decreased from 13.9% in the period from 1968-1998 to 8.5% during the period of 1998- 2013 (Canadian Ice Service, 2014). Forecasts obtained for some study sites on the Côte-Nord and Îles-de-la-Madeleine indicate that the number of days during which the ice foot is complete and protects the coast from wave action will decrease by around 38 to 53 days, if we compare the period 1981-2010 to the projected period of 2041-2070 (Senneville et al., 2014). Moreover, all indications suggest that this trend is already underway: for the period 2008-2012, the number of days during which the ice foot was complete was sometimes even lower than what is predicted for the 2055 horizon.
This decrease in the coastal ice increases the length of time that the coast is exposed to hydrodynamic agents. Consequently, the coast is likely to be exposed to a greater number of storm events. However, the direct consequences of the reduced ice cover on shoreline retreat rates have rarely been quantified until now. The only results available to us indicate that in Îles- de-la-Madeleine, periods of low freeze-up correspond to periods marked by reduced beach widths and subsequent coastline retreat (Bernatchez et al., 2008). The reduced ice cover could therefore be responsible for a significant part of the recent increase in beach sediment deficit
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(Bernatchez and Dubois, 2004). This beach sediment deficit, in turn, could explain the significant increase in the number of storm events that damaged the coast between 2000 and 2010 (Bernatchez et al., 2012a).
Lastly, the period from 1987 to today has seen a significant acceleration in relative sea level rise in the north-eastern United States and eastern Canada (Boon, 2012). This acceleration has also been recorded in Quebec, in the Gulf of St. Lawrence (Bernatchez et al., 2013). This is thus not a local phenomenon, as it is following the upward trend of global sea level rise (Vermeer and Rahmstorf, 2009). The trend of global sea level rise has also increased from 1.7 ± 0.2 mm/year between 1900 and 2009 (Church and White, 2011) to 3.2 ± 0.5 mm/year between 1993 and 2011 (Rahmstorf et al., 2012). Moreover, the Gulf of St. Lawrence region is amongst world regions where the trend of sea level rise has been the highest (Slangen et al., 2014).
2.1.2 Coastal change patterns and delineation of homogeneous geomorphological units
Applying coastal change projections involves excellent preliminary knowledge of coastal hydro- sedimentary dynamics at the local level. To obtain accurate projections, they must be calculated based on homogeneous geomorphological units that reflect similar physical characteristics. These units are similar to Lee and Clark’s (2002) cliff behaviour units, which are cliff sections with similar geology and hydrodynamics. Unit characteristics are defined by coast type, lithological and stratigraphic composition, shoreline migration rates and coastal change patterns. The identification of homogeneous geomorphological units must also take into account the limits of hydro-sedimentary cells and the direction of sediment transport by longshore drift. The coastline of maritime Quebec has thus been divided into homogeneous geomorphological units to which coastal change projections are applied for different time horizons up to 2065.
The analysis of coastal change at high temporal and spatial resolution performed in recent years by the LDGIZC and the UQAR coastal geoscience research chair has shown that different patterns of coastal evolution exist along the coasts of maritime Quebec, particularly because of the diversity in the types of coastlines and their high lithostratigraphic variability. This high geodiversity of coastal systems in maritime Quebec consequently results in a large number of erosion processes, amounting to more than 20 (Bernatchez and Dubois, 2004). While cliff retreat mechanisms have been well quantified thus far, (Bernatchez, 2003; Bernatchez et Dubois, 2008; Corriveau, 2010; Boucher-Brossard, 2013; Bernatchez et al., 2011b; Bernatchez et al., 2014), this has not been the case for low sandy coasts (beach terrace, spit, dune, tombolo, barrier beach).
Low sandy coasts are genetic forms of coastal accumulation. They develop from a succession of advances and retreats over time, and retreats are often associated with storm events (Bernatchez and Dubois, 2004). The change outcome for a given period can therefore be negative (erosion), positive (accumulation and progradation) or stable. Even if the measurement of the shoreline is stable for a given period, this does not necessarily mean that the shoreline is not dynamic and did not move during that time interval. Analyses of the historical rate of shoreline change have revealed different patterns of change. The pattern of change may be cyclic, where alternating periods of retreat and advance maintain a rather stable sediment
4 budget, one that is even positive in some cases. This is particularly the case in certain areas of Natashquan (Bernatchez et al., 2012b), Sept-Îles (Bernatchez et al., 2012c) and Îles-de-la- Madeleine (Bernatchez et al., 2010). For other areas where longshore drift is significant and virtually unidirectional, shoreline migration is seen in a saw tooth pattern, where retreat and advancement points move over time in the direction of sediment transport (Bernatchez et al., 2008). Other sectors record strong shoreline retreat during storms, which is completely offset by accumulations after only a few years, so that the budget remains rather stable over time. This is particularly the case in several areas of the south shore of the St. Lawrence. Detailed analysis of each coastal system is therefore important in order to delineate homogeneous geomorphological units that conform to the coastal change patterns and the dynamic of the area.
2.1.3 Choosing probable migration rate
For each homogeneous geomorphological unit, choosing the most likely migration rate must be based on projected climatic and oceanographic conditions. In maritime Quebec, several studies have been conducted since the 2000s and have been used to calculate a probable rate of shoreline or coastline migration for much of the territory (Dubois et al., 2006; Bernatchez et al. 2008, Bernatchez et al., 2010; Bernatchez et al., 2012b, c, d, e; Bernatchez et al., 2013; Drejza et al., 2014a, b; Fraser et al., 2014a, b, c). Each rate was selected based on knowledge at the time regarding the speed and evolutionary mechanisms in each sector. The calculation methods therefore differ from one region to the next as they changed with the advancement of scientific knowledge. In addition, data on the rate of coastal change are not available for all of Quebec’s maritime coasts. The combination of various information sources was therefore needed in order to attribute the most probable migration rate by 2065 to the homogeneous geomorphological units (table 1 and 2). The choice of the data source used to assess future economic losses was made in the following order of priority:
1- Presence of recent coastal change data (≈1990 to present) (15% of coasts covered); 2- Presence of data derived from the coastal erosion monitoring network of the LDGIZC (2000- 2012) when the density of measuring stations is high within a single homogeneous segment (20% of coasts covered); 3- Presence of historical coastal change data (42% of coasts covered); 4- Use of the mean measurement per coast type from monitoring stations in a homogeneous region (e.g. Chaleur Bay, Côte-Nord) between 2000 and 2012 (24% of coasts covered).
The diversity of data sources did not make it possible to distinguish the contribution of climate change for each rate of retreat. However, based on the knowledge acquired (Section 2.1.1), it is reasonable to believe that the shoreline migration values measured during the recent period are largely the result of climate change and these values are likely to persist between now and 2065. The recent period was therefore readily chosen in at least 58% of coasts (case numbers 1, 2 and 4). In case number 3, where historical data were available, the recent period was chosen for the most part, but an earlier period was also prioritized based on the coastal change pattern that would best represent expected conditions with climate change (often the period where rates were highest). We thus assume that probable scenarios all take disturbances due to climate change into account.
A probable rate was determined for 65% of the coasts in the study (2096 km). The probable rates expected for these coasts will help to project future change for each homogeneous
5 geomorphological unit by 2025, 2045 and 2065 and thus identify exposed infrastructure. The other 35% (1123 km) have no rate of retreat or safety margin. These are the granitic coasts of the Côte-Nord and port areas that are considered stable.
2.1.4 Coastal protection works
The probable rate is based on historical change of each homogeneous geomorphological unit with or without protection works. Thus, when works in place for a few decades have stabilized the coastline, the probable rate can be zero or very low. If work is recent and historical change measurements have recorded retreats, a probable retreat rate will be projected even if protection work is in place. In fact, the working assumption is that no new adaptation measures are put in place and existing measures are not maintained. It is therefore possible for buildings or infrastructure located in an area with protection works to be considered as exposed in the short, medium or long term. The actual exposure date will depend on design quality and works maintenance. Where transport infrastructure is concerned, it is assumed that the necessary resources are available to maintain service, whether the optimal strategy is to reinforce the protection or move the infrastructure.
These methodological choices were made because it is impossible to ascertain the degree of maintenance of existing works beyond a reasonable doubt. In addition, as observed during the storm of December 6, 2010, even recent protection works in good condition can be completely damaged and retreats of several metres can be measured (Quintin et al., 2013). Moreover, during this storm, retreat behind the protection structures was similar and sometimes greater than seen in areas without protection works (Quintin et al., 2013). These works can be repaired or rebuilt or even abandoned, leaving the coast to evolve naturally. Lastly, the choice of considering some infrastructure as potentially exposed, even if it is currently bordered by protection works, brings to light the importance of maintaining these works and can also help to guide managers in terms of land use planning.
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Table 1. Data available to establish coastal change scenarios, Côte-Nord*
Places Probable scenario Periode (method) References CÔTE-NORD Maximal mean erosion rate 1931 to 1996 (photos) or Dubois et al., 2006 Tadoussac to baie des Îlets-Jérémie 2000-2005 (measuring stations) S1 (historical shoreline change rate) or 1950 to 1996 or 2006 (photos) Bernatchez et al. 2012b From baie des Îlets Jérémie to S2 (mean of historical shoreline change rates Papinachois (Innus) for a 10-15 year period). From Papinachois to Ragueneau Mean maximal erosion rate 1931 to 1996 (photos) or Dubois et al., 2006 River 2000-2008 (measuring stations) S2 (mean of retreat rates for the most active 2001-2008 (photos) or Internal documents (LDGIZC) From Ragueneau River to Chute-aux- period) Outardes 2000-2008 (measuring stations) Mean migration rate of measuring stations in 2000-2012 (measuring stations) Internal documents (LDGIZC) Estuary of rivière aux Outardes (Les the sector or regional mean of measuring Modified data from Bernatchez, 2003 and Dubois et al. , 2006 Buissons) stations by type of coast in the region (2000- 2012) From pointe du Bout to Baie-Saint- S2 (mean of retreat rates for the most active 1931 to 2008 (photos) Internal documents (LDGIZC) Ludger (Pointe-aux-Outardes) period) Modified data from Bernatchez, 2003 From Baie-Saint-Ludger to pointe S2 (mean of retreat rate for the most active 1931 to 2007 (photos) Internal documents (LDGIZC) Lebel (Pointe-Lebel) period) Modified data from Bernatchez, 2003 Internal documents (LDGIZC) From Baie-Comeau to Rivière- Maximal mean erosion rate 1931 to 1996 (photos) or Modified data from Dubois et al., 2006 Brochu 2000-2008 (measuring stations) Rivière Brochu S1 (historical shoreline change rate) or 1931 to 2005 (photos) Bernatchez et al. 2012c S2 (mean of historical shoreline change rates measured in a 3-14 year period) S1 (historical shoreline change rate) or 1931-2006 (photos) Bernatchez et al. 2008 Gallix and Ste-Marguerite S2 (mean of retreat rates for the most active period) From Val-Marguerite to pointe du Maximal mean erosion rate 1931 to 1996 (photos) or Dubois et al., 2006 Poste 2000-2005 (measuring stations) S1 (historical shoreline change rate) or 1931 to 2005 (or 2006 for Mani- Bernatchez et al. 2012c From pointe du Poste to rivière Utenam) (photos) Moisie S2 (mean of historical shoreline change rates measured in a 3-14 year period) From Moisie River to Matamek Maximal mean erosion rate 1931 to 1996 (photos) ou Dubois et al., 2006 River 2000-2005 (measuring stations) From Matamek River to Rivière-au- S2 (Mean of retreat rates for the most active 1975-76 à 2005 (photos) Internal documents (LDGIZC) Bouleau period) Modified data from Dubois et al., 2006 S2 (mean of retreat rates for the most active 1975-1976 or 1987-1989 to Internal documents (LDGIZC) Rivière-au-Tonnerre period) 2005 (photos) or Modified data from Dubois et al., 2006 2000-2008 (measuring stations) S2 (mean of retreat rates for the most active 1975-1976 or 1989 to 2005 Internal documents (LDGIZC) Saint-Jean River period) (photos) or Modified data from Dubois et al., 2006 2000-2008 (measuring stations) S1 (historical shoreline change rate) or 1948 to 2005 (photos) Bernatchez et al. 2012e From Saint-Jean River to Romaine S2 (mean of historical shoreline change rates River measured in a 6-19 year period). S2 (mean of retreat rate for the most active 1989 à 2005 (photos) or Internal documents (LDGIZC) From Romaine River to Havre-St- period) Modified data from Dubois et al., 2006 Pierre village 2000-2008 (measuring stations) S2 (mean of retreat rates for the most active 1933-2005 (photos) or Internal documents (LDGIZC) Havre-St-Pierre village period) Modified data from Dubois et al., 2006 2000-2008 (measuring stations) S2 (mean of retreat rates for the most active 1933-2005 (photos) or Internal documents (LDGIZC) Est of Havre-St-Pierre village to Baie- period) Modified data from Dubois et al., 2006 Nickerson 2000-2008 (measuring stations) Regional mean migration rate of measuring 2000-2012 (measuring stations) Internal documents (LDGIZC) Baie Nickerson to pointe stations by type of coast in the region (2000- Pashashibou (Aguanish) 2012) S2 (mean of retreat rates for the most active 1933-2005 (photos) or Internal documents (LDGIZC) Pointe Pashashibou to Natashquan period) Modified data from Dubois et al., 2006 River 2000-2008 (measuring stations) S1 (historical shoreline change rate) or 1930 to 2005 (photos) Bernatchez et al., 2012b Natashquan River to pointe du S2 (mean of historical shoreline change rates Vieux poste measured in a 8 - 19 year period)
* S1, S2 and S3 reference scenarios previously developed in the studies cited and represent the most optimistic to the most pessimistic, respectively.
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Table 2. Data available to establish coastal change scenarios, Bas-Saint-Laurent, Gaspésie and Îles-de-la- Madeleine*
Places Probable scenario Periode (method) References BAS-SAINT-LAURENT-GASPÉSIE-ÎLES DE LA MADELEINE Mean migration rate of measuring stations in 2005 to 2012 (bornes) Internal documents (LDGIZC) From La Pocatière to quai de Pointe- the sector or regional mean of measuring au-Père stations by type of coast in the region (2005- From quai de Pointe-au-Père to S22012) (mean of historical shoreline change rates 1948-50 to 2012 (photos) Internal documents (LDGIZC) Matane for the 1992-1993-2012 period). S2 (mean of historical shoreline change rates 1938-1939 to 2012 (photos) Internal documents (LDGIZC) Matane to quai de Tourelle for the 1992-1993-2012 period). Mean migration rate of measuring stations in 2002 to 2012 (measuring stations) Internal documents (LDGIZC) the sector or regional mean of measuring From Tourelle to Penouille stations by type of coast in the region (2002- 2012) S2 (mean of historical shoreline change rates 1948 to 2010 (photos) Bernatchez et al., 2013 Penouille for the most representative future change period, 1993-2010). Mean migration rate of measuring stations in 2004 to 2012 (measuring stations) Internal documents (LDGIZC) the sector or regional mean of measuring Baie de Gaspé stations by type of coast in the region (2004- 2012) S2 (mean of historical shoreline change rates 1948 to 2010 (photos) Bernatchez et al., 2013 Sandy Beach for the most representative future change period, 1993-2010). Mean migration rate of measuring stations in 2004-2012 Internal documents (LDGIZC) Sandy Beach to Pointe-St-Pierre the sector or regional mean of measuring (Percé) stations by type of coast in the region (2004- 2012) S2 (mean of retreat rates of the most active 1931 to 2001 (photos) Bernatchez et al., 2008 period between 1931 and 2001) or From pointe St-Pierre to cap Barré S3 (mean of retreat values higher than the mean of retreat rates of the most active period between 1931 and 2001) S2 (mean of historical shoreline change rates 1931 to 2013 (photos) Internal documents (LDGIZC), Projet ACA From cap Barré to cap Blanc for the most representative future change 2014, modified data from Bernatchez et al. 2008 period 1992-2013) S2 (mean of retreat rates for the most active 1931 to 2001 (photos) Bernatchez et al. 2008 period between 1931 to 2001) or From cap Blanc to cap d'Espoir S3 (mean of retreat values higher than the mean of retreat rates for the most active period between 1931 et 2001) Mean migration rate of measuring stations in 2004 to 2012 (measuring stations) Internal documents (LDGIZC) the sector or regional mean of measuring From cap d'Espoir to Shigawake stations by type of coast in the region (2004- 2012) S1 (historical shoreline change rate) or 1934 to 2007 (photos) Internal documents (LDGIZC) S2 (mean of retreat rates for the most active 2005-2010 (measuring stations) From Shigawake to Cascapédia River period between 1934 and 2007) or mean of measuring stations (2005-2011) S1 (historical shoreline change rate) or 1934 to 2001 or 2007 (photos) Internal documents (LDGIZC) From rivière Cascapédia to Pointe-à- S2 (mean of retreat rates for the most active 2005-2011 (measuring stations) la-Garde period between 1934 to 2007) or measuring stations mean (2005-2011) From Pointe-à-la-Garde to Pointe-à- Regional mean migration rate of measuring 2004 to 2012 (measuring stations) Internal documents (LDGIZC) la-Croix (bridge) stations by type of coast (2004-2012) S1 (mean of historical change rate) or 1963 à 2008 (photos) Internal documents (LDGIZC) S2 (mean of retreat rates or historical shoreline 2005 to 2010 (measuring stations) Îles de la Madeleine change rates for the most active period according to the lenght of periods)
* S1, S2 and S3 reference scenarios previously developed in the studies cited and represent the most optimistic to the most pessimistic, respectively.
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2.1.5 Coasts that accumulate sediments
Coastal segments can sometimes have a positive balance in the long term. This does not exclude the fact that they can occasionally retreat during a storm event. Thus, in these areas, infrastructure at a lesser distance than the safety margin (see section 2.5) was all considered as being exposed by 2015 and is therefore included in the 2025 horizon. 2.2 Mapping of exposed elements
Prior to calculating the exposure of infrastructure to erosion, significant data processing work was needed to confirm the position of the infrastructure. The approach used is strongly inspired by Fraser et al. (2014a, 2014b).
2.2.1 Point data processing: buildings and land
The assessment roll was used to identify buildings and land areas, as well as to obtain the type of use and property value. Using the most recently available aerial orthophotos, each centroid on the graphic register located within 150 m of the coast was moved to the seaward side of the buildings, so as to be located at the point closest to the coastline. When the image resolution allowed, the reference scale was 1:500, and when the resolution was less precise, points were moved based on a scale of 1:2000. Oblique photos taken by helicopter in September 2010 by the LDGIZC at UQAR were also used to obtain greater precision. The identification and use of the buildings were validated using graphic registers provided by each of the RCMs, with the exception of the Manicouagan RCM, the city of Port-Cartier in the RCM of Sept-Rivières, the RCM of Minganie, Rocher-Percé (except the area from L’Anse du Nord to Cap Blanc) and in the city of Matane in the RCM of Matanie.
Many secondary buildings and other buildings not inventoried in the 2010 assessment roll data were indexed on the images and then incorporated into the database. Because secondary buildings were not specifically identified in the assessment roll database, their value is included in that of the main building on the same grounds. The type of use of other non-inventoried buildings is unknown; they therefore have no associated property values. This inventory of secondary buildings was not performed consistently throughout the entire territory. The data are thus presented for illustrative purposes only. For the purposes of the study, five building classes were defined (table 3). Undeveloped land is also identified using the centroid point of the graphic register. These points were not moved and are thus located in the centre of each territory.
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Table 3. Building classes
Buildings classes Description and codes associated to the assessment roll
Include all main and secondary residences, as well as rental buildings (1000 to Residential 1990). Include manufacturing industries (2000 to 3999), exploitation and extraction of Industrial natural resources, such as agriculture, mines, hunting and fishing (8000 to 8900). Commercial Include all commercial buildings (5000 to 5999). Include transportation, communication and public service buildings (4000 to 4990), service buildings, for example, financial services, business, health Services services or staff (6000 to 6999), as well as recreational, leisure and cultural heritage buildings (7000 to 7990). Include buildings added manually when the points were moved. They can Undetermined represent new constructions or secondary buildings.
2.2.2 Linear data processing: roads and railways
Linear infrastructure included in this study includes provincial highways, municipal and local roads, as well as railways (table 4). Roads and railways were extracted from the Quebec Topographic Database (BDTQ). Using the latest aerial and satellite imagery, the plots were then edited to run along the seaward side of the infrastructure. In some cases, they were manually digitized so that the plot would be up to date. This digitizing was done according to the same criteria in Section 2.2.1, namely 1: 500 or 1: 2000 based on the quality of the imaging. Once all of the plots were validated, segmentation was done to obtain segments of 10 m. Bridges and port infrastructures were excluded from the analysis.
Table 4. Classes of linear infrastructure
Classes of linear Description infrastructure This is highway 20 that runs along the south shore of the St-Lawrence Freeway River. Include highway 132 that runs along the coast of Bas-Saint-Laurent and National highways Gaspésie, highway 138 in the Côte-Nord and highway 199 in Îles-de-la- Madeleine. Include paved and unpaved roads under municipal jurisdiction, private Municipal and local roads roads and other non-specified roads. Railways used for passengers and goods transportation in Bas-Saint- Railways Laurent and Gaspésie, and the industrial railroad in Baie-Comeau in the Côte-Nord.
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2.3 Calculation of exposure
For each point representing a building or terrain and for each line representing a 10-metre segment of linear infrastructure, the closest distance to the shoreline or coastline was calculated automatically using a feature in ArcGIS software. Manual validation was then performed. Exposure is based on two parameters: 1) the probable rate of shoreline or coastline migration estimated for each homogeneous geomorphological unit (see Section 2.1) and 2) the safety margin attributed according to various criteria (see Section 2.5). All of the data presented in this report take these two parameters into consideration.
The projected future migration rate is the most probable rate taking recent climate changes into account. The equation used to calculate building exposure in number of remaining years in a safe zone is shown in Figure 2. This is done by measuring the distance between the element and the current shoreline or coastline, subtracting the safety margin and dividing the difference by the probable annual migration rate to obtain the number of years before the element is exposed. Building exposure is then presented based on 3 time horizons: 2025 (short term), 2045 (medium term) and 2065 (long term).
Number of years Distance between Probable before the element the element and the Safety annual shoreline or margin will be exposed migration coastline rate
Figure 2. Equation used to calculate the exposure of buildings, land and transport infrastructure to coastal erosion (modified from Fraser et al., 2014a, b, c; Drejza et al., 2014a, b)
As explained in Section 2.1.3, coastal change data are not available for the same periods in all regions. Therefore, the most recent coastline values vary between 1996 and 2013 (table 1 and Table 2). All of the buildings or infrastructure located at a lesser distance than the safety margin are considered exposed as of 2015. The same applies for all buildings or infrastructure for which the exposure calculation results in a year of exposure prior to 2015. Between 1996 and 2015, however, it is possible that retreat was controlled by protection work, or that the building or infrastructure has since been moved, which may overestimate the number and value for 2015.
When a short road or railway segment that is considered non-exposed based on the calculations is located between two exposed segments, smoothing was done to include this segment in exposed infrastructure. This is often the case with portions of beach terraces that vary in width in front of the infrastructure, thus varying the distance used to calculate exposure. Operationally and technically speaking, repairing or rebuilding a road without considering the adjacent segments that are still close to the shoreline or the coastline is unlikely. It was therefore considered appropriate to standardize areas where exposure is intermittent.
Sometimes a building or infrastructure is sometimes located directly on the face of the cliff, i.e. in front of the coastline used to calculate the distance. In these rare exceptional cases, the
11 distance between the coast and the infrastructure is negative. This is why the infrastructure in this situation is automatically considered as being exposed by 2015 and therefore included in the 2025 horizon.
2.4 Safety margin
2.4.1 Margin proposed for buildings
A safety margin was used in the exposure calculation to reflect potential coastline retreat during storm events that can result in losses. Due to the importance of the length of shoreline to analyze, fixed margins were selected based on three principal coast types. The margins are five metres for low-lying coasts, ten metres for mobile and rocky cliffs, and 15 m for mobile cliffs with a clay unit (table 5). The margin of 15 m serves to take into account the magnitude of the largest retreat associated with landslides in clay soils. The width of the margins was defined based on the minimum strip of land needed to safely intervene when infrastructure is in imminent danger. For comparison, the results obtained without using safety margins are also presented in this report.
Table 5. Safety margins width
Coast type Width of the safety margin (m) Low-lying coasts (less than 5 m of height) 5 Cliffs (5 m of height or more) 10 Clay cliffs 15
2.4.2 Margin proposed for roads and railways
A 5-metre safety margin was added to the edge of the transport infrastructure equipped with protective works in the calculation of anticipated losses. This decision was made because maintenance or replacement work on these protection works and/or roads will undoubtedly be needed by 2065. Manual validation was performed in order to include transport infrastructure equipped with a protection structure against coastal erosion, even for segments located at a distance greater than 5 metres from the coastline, but situated between two road segments located less than 5 metres away. Operationally speaking, it would be illogical to perform replacement work on discontinuous segments. For comparison, the results obtained without using safety margins are also presented in this report.
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2.5 Economic evaluation of exposed elements
Having the mapping and year of exposure of each element exposed to coastal erosion, the next step was to perform an economic evaluation of these elements. This assessment is primarily based on the economic principles shown below. Estimating the value of elements exposed over 50 years was performed separately for buildings, transport infrastructure and developed and undeveloped land.
2.5.1 Economic evaluation principles
There are three starting assumptions that frame the economic evaluation performed for this study. The first is the choice of the monetary unit. It was decided that constant 2012 dollars be used. The second assumption concerns the study period and estimation intervals. Evaluation of the value of potential losses resulting from buildings and land being exposed to erosion by 2065 was estimated on an annual basis, as the year of exposure was known (see Section 2.4). In the case of transport infrastructure, because the year of exposure is not precisely known, all exposed infrastructure by 2065 was considered overall and replacement costs were evenly distributed throughout the entire period, i.e. 50 years (from 2015 to 2064 inclusively). The final assumption concerns the discount rate used to take the temporal distribution of infrastructure exposure into account. Because the losses are realized at different times during the study period, the dollar value of annual losses should be brought to a common time basis. Discounting is therefore applied to compare monetary flows that occur at various points in time. Discounting is based on the fact that people generally prefer to enjoy their money immediately rather than enjoy the same amounts later on in time.
Moreover, selecting a discount rate is an aspect that proves to be complex. The preferred rate to compare the present to the future varies from person to person and fluctuates considerably over time depending on social, environmental and economic events. The time horizon of the study also must be taken into account. As a general rule, in a study on an intergenerational scale such as this (50 years), a rate between 3 and 7% is recommended (Dupras et al., 2013). This rate should be expressed in real terms, i.e. excluding inflation. Considering these factors and the discussions that persist in the literature, it is preferable to perform a sensitivity analysis by varying the discount rate. As this study is part of the regional economic evaluations funded by Natural Resources Canada, the discount rate used is consistent with the guiding principles established for the entire project, i.e. 4%, with a sensitivity analysis at 2% and 6%.
2.5.2 Property assessment of buildings
The economic evaluation of buildings is based on the use of property assessment rolls by the municipalities, updated every three years based on observed market values. Although property assessments are still considered inferior to the market value of land holdings in several municipalities, they are still the most reliable source available for evaluation. Therefore, in terms of this evaluation, it can be assumed that the estimate of potential losses in buildings represents a minimum value.
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The property value data were provided by the Ministry of Municipal Affairs and Land Occupancy (MAMOT). These data are taken from the 2010 assessment roll for all municipalities except the municipalities of the RCM of Kamouraska, the RCM of Rimouski-Neigette and the municipality of Sainte-Anne-des-Monts. For these latter municipalities, the 2014 assessment roll was used.
In order to evaluate the losses in 2012 dollars, property data were adjusted to the 2012 value, regardless of the year of origin. In Quebec, when a new assessment roll comes into force, the values shown reflect prevailing market conditions 18 months prior to the effective date. For example, if an assessment roll comes into force on the 1st of January, 2014, the values entered on the assessment roll were established based on property market conditions as of the 1st of July 2012. Furthermore, assessment rolls in Quebec are prepared on the basis of a three-year cycle that is not standardized throughout the province. Considering these two factors, the property values obtained for this study represented market conditions observed between the 1st of July, 2006 and the 1st of July 2012, depending on the case.
In order to bring these values to market conditions in July 2012, adjustments were made based on the year of the assessment roll. First, in the case of values taken from real estate assessment rolls dating back to 2010, the adjustment was made using a factor corresponding to the rate of increase in the average value of evaluation units in each municipality between the 2010 and 2014 rolls. This adjustment factor was calculated using MAMOT property assessment roll data (MAMOT, 2014) and was used to transpose values from 2010 rolls to 2014 roll values. Next, the new values obtained underwent a second adjustment to bring them to July 2012 market conditions, due to the difference between the roll filing date and the reference date of the values observed in the housing market. To accomplish this, the 2014 comparative factor calculated by the MAMOT was used (see www.mamrot.gouv.qc.ca/evaluation- fonciere/proportions-medianes-des-roles/description). This factor is constructed by calculating the ratios between actual sale prices and the evaluation values for the same year and the MAMOT then uses the median of these ratios as the adjustment factor.
2.5.3 Value of replacing or moving roads and railways
Estimating potential losses in terms of transport infrastructure essentially consists of assessing the replacement cost of the infrastructure affected by coastal erosion. Thus, the value of damage to transport infrastructure is calculated based on the replacement cost per kilometer and by type of infrastructure (railway, freeway, national highway, municipal road and private road), taking into account the geographical situation and existing or necessary coastal protection for each segment (see Table 5).
The replacement value of linear infrastructure is not uniform along plots. Each segment has various characteristics and constraints that influence costs, and the economic evaluation has attempted to take the specificities of the different types of coasts into account. When moving an infrastructure was less expensive than protecting it, this became the preferred option and expropriation costs were added. Thus, it is generally less costly to move a national road corridor on the Côte-Nord than on the Gaspésie since most of the territory is on public land and developed areas are not very dense. When the land expropriation costs are very high, such as on the Gaspésie, the maintenance and protection of the road corridor in its current location is the optimal solution.
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In order to establish a fair assessment of construction costs, i.e. coastal protection works and various categories of road infrastructure (national, local, municipal, access road), a review was performed of recently completed technical reports for various projects in the regions covered by the study (Table 6). Unit costs, i.e. per linear metre or kilometer were identified for each type of works. In addition, consultations with engineers from the project departments of various regional branches of Quebec’s ministry of transportation served to estimate the overall costs for each of the regions. Only the unit rates shown in bold in Table 6 were used for the purposes of the evaluation. Generally speaking, these unit costs represent an average of the costs of major works carried out by Quebec’s ministry of transportation, and in some situations, the cost of work carried out recently were also used.
In fact, in each region of Quebec, construction costs are influenced by the quantity, proximity and quality of materials available. On the Côte-Nord, the higher number of quarries with the requisite materials (geological granite formations) explains why unit rates are generally lower. In Chaleur Bay, the scarcity of sources of heavy, non-brittle stone increases costs by a factor of three compared to those on the Côte-Nord, mainly due to the long transportation distances. This lack of proper stone supply is particularly acute in Îles-de-la-Madeleine, where it is necessary to transport heavy stone from Nova Scotia.
Average unit replacement costs by type of infrastructure were developed using mapping of vulnerable segments in each municipality. In addition to integrating the variability of material costs by region, these unit costs were estimated by taking the main characteristics of vulnerable infrastructure into account (soil type, coast type, need for protection or displacement, etc.). These unit costs are presented in Table 6 by type of infrastructure. They were then multiplied by the length of the segments exposed within the study horizon in order to obtain the economic value of anticipated impacts.
Lastly, the overall estimated costs for the replacement and protection of transport infrastructure were revised upward by 15% to cover costs related to engineering studies and site monitoring.
It is important to emphasize that the evaluation performed provides a general idea of estimated replacement costs and not actual costs. No engineering study on the vulnerable segments was performed to obtain detailed costs. Moreover, given the length of the segments studied, i.e. 10 metres, it is likely that the costs have been underestimated. In fact, the replacement of exposed segments situated between unexposed segments sometimes requires the replacement of entire segments of transport infrastructure. Although this possibility was taken into account by smoothing segments in certain cases, it was impossible to systematically identify all cases where unexposed segments should also be replaced or protected, due to the scale of the analysis. For all of these reasons, the estimates presented in this report should not be used as a reference for forecasting expenses related to the maintenance of transport infrastructure in a given region.
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Table 6. Average replacement cost in 2012 dollars (CAN) per metre by type of infrastructure and by municipality
Bas-Saint-Laurent Gaspésie/Îles-de-la-Madeleine Côte-Nord Municipality National Municipal Unidentified Highway 20 Railway Municipality National Municipal Unidentified Railway Municipality National Municipal Unidentified Railway Baie-des-Sables 1000 800 800 - - Bonaventure 2500 1000 800 - Aguanish 1000 250 250 - Cacouna 1000 800 800 - - Cap-Chat 1000 1000 800 - Baie-Comeau 1000 5000 0 4000 Grand-Métis 1000 800 800 - - Caplan 1500 1000 800 10000 Baie-Johan-Beetz 1000 250 250 - Grosses-Roches 1000 800 800 - - Carleton-sur-Mer 3000 2000 1500 10000 Baie-Trinité 1000 250 50 - Kamouraska 1000 800 800 - - Cascapédia–Saint-Jules 1000 800 800 - Chute-aux-Outardes 1000 250 50 - La Pocatière 1000 800 800 - - Chandler 1500 1500 1000 5000 Colombier 2000 250 50 - Les Méchins 1000 1000 800 - - Cloridorme 4500 800 800 - Essipit 1000 250 50 - L'Isle-Verte 1000 500 800 - - Escuminac 2000 1500 800 - Forestville 1000 2500 50 - Matane 3000 1000 800 - - Gaspé 2000 2000 1500 2000 Franquelin 1000 0 50 - Métis-sur-Mer 1000 800 800 - - Gesgapegiag 1000 800 800 - Godbout 1000 2500 50 - Mont-Joli 1000 800 800 - - Grande-Rivière 1500 800 800 2500 Havre-Saint-Pierre 1000 250 1000 - Notre-Dame- 1000 800 800 - 5000 Grande-Vallée 1000 800 800 - Les Bergeronnes 1000 250 50 - des-Neiges Notre-Dame- 1000 800 800 - - Grosse-Île 1000 250 50 - Les Escoumins 1000 250 1000 - des-Sept-Douleurs Notre-Dame- 1000 250 1000 - - Hope 1500 1000 800 - Longue-Pointe-de-Mingan 3500 250 250 - du-Portage Rimouski 1000 800 800 - 1500 Hope Town 1500 1000 800 - Longue-Rive 1000 250 50 - Rivière-du-Loup 1000 1000 1000 5000 - La Martre 2000 800 800 - Maliotenam 1000 250 50 - Les Îles-de-la- Rivière-Ouelle 1000 1000 800 - - 4000 4000 4000 - Mingan 1000 250 50 - Madeleine Saint-André 1000 800 800 - - Maria 5000 3000 2000 - Natashquan 1000 250 50 - Saint-Denis 1000 250 800 - - Marsoui 4500 800 800 - Pessamit 1000 250 50 - Sainte-Anne-de- 1000 800 800 5000 - Mont-Saint-Pierre 5000 800 800 - Pointe-aux-Outardes 1000 1000 50 - la-Pocatière Sainte-Félicité 1000 1000 800 - - New Carlisle 1000 1000 800 5000 Pointe-Lebel 1000 2000 50 - Sainte-Flavie 1000 800 800 - - New Richmond 2000 2000 1000 10000 Port-Cartier 1000 500 250 - Sainte-Luce 1000 800 800 - - Nouvelle 1500 1000 1500 - Portneuf-sur-Mer 1000 1000 50 - Saint-Fabien 1000 800 800 - - Paspébiac 1000 1000 800 5000 Ragueneau 1000 1000 50 - Saint-Germain 1000 50 800 - - Percé 3500 800 800 2000 Rivière-au-Tonnerre 1000 250 250 - Saint-Simon 1000 800 800 - - Petite-Vallée 1000 800 1000 - Rivière-Saint-Jean 3500 250 50 - Saint-Ulric 1000 1000 800 - - Pointe-à-la-Croix 1000 250 1500 - Sept-Îles 1000 250 1000 - Trois-Pistoles 1000 800 800 - - Port-Daniel - Gascons 1500 1000 1000 2000 Tadoussac 5000 5000 1000 - Rivière-à-Claude 4500 800 1000 - TNO Lac-Jérôme 1000 250 50 - Sainte-Anne-des-Monts 1000 1000 1000 - Uashat 1000 250 50 - Sainte-Madeleine-de- 4500 800 1000 - la-Rivière-Madeleine Sainte-Thérèse- 1000 800 800 - de-Gaspé Saint-Godefroi 1500 800 250 - Saint-Maxime-du- 5000 800 800 - Mont-Louis Saint-Siméon 2500 1000 800 10000 Shigawake 1500 800 250 - TNO Rivière- 1000 800 800 - Saint-Jean
Note: The "unidentified" category does not only include gravel access roads. In some municipalities, these are municipal roads that have not been adequately classified and that may require protection works in addition to replacement.
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Table 7. Examples of unit costs for linear infrastructure and coastal protection works
Unit costs* Sources and Region Types of work Variants Territory Retained unit costs references** Côte-Nord 900 mm; MTQ Baie-Comeau, Ballasting 1 K $ / linear meter Côte-Nord 3 m h Services projets 900 – 1000 mm; Ballasting 4 K $ / linear meter Tadoussac Génivar (2012a) 4 m h 900 – 1000 mm; Ballasting 5,1 K$ / linear meter Sept-Îles Project Ropars Inc (2007) 75 $ m3; 7 m high Pointe-aux- Ballasting 900 – 1000 mm 1,3 K$ / linear meter TDA (2011) Outardes Concrete seawall 3,6 m high 5 K$ / linear meter Tadoussac Génivar (2012a) Beach d50 25 mm- 7,5 m 4 K $ / linear meter Tadoussac Génivar (2012a) replenishment beach Break water 2 K $ / linear meter Longue-Rive BPR & Ropars (2008) Rock mattress 200 $ / linear meter Tadoussac Génivar (2012a) Unpaved Flat land, access Research team secondary Mean value 250 $ / linear meter road (minimum estimation municipal road foundation) Gravel road Research team without 50 $ / linear meter Loose flat land estimation foundation National road MTQ -Baie-Comeau, Smooth terrain 2 M / km Côte-Nord construction Services projets National road MTQ -Baie-Comeau, Difficult 3,5 M / km Côte-Nord construction Services projets Acquisition of MTQ -Baie-Comeau, Displacement 1,5 M / km Côte-Nord private land Services projets Manicouagan Municipalité de Pointe- Main municipal Mean value 650 K $/ km Pointe aux aux-Outardes (2006) road Works completed in local roads Outardes on sandy surfaces in 2006. Basse- Rough terrain with 3,5 M$/ km on gravel Cost increased MTQ -Baie-Comeau, Côte-Nord rare materials X 3 for all the Services projets Basse-Côte- Nord Bas-Saint- Ballasting d50 600 mm 450 $ / linear meter Ste-Luce Sainte-Luce Municipality Laurent plan concept; (2011) General description of a Rock quantities vary classic rip-rap proposed to according to the terrain. residents Sheet piling 3 K $/ linear meter Ste-Luce Génivar (2012b) Ballasting D5- 1000 mm 58$ per cubic meter Matane Ropars (2012b) National road Rough terrain 3 M $/ km General costs MTQ, Direction des per unit Projets Ballasting 53 m3/ m 52 $ / linear meter Grosse Roche Ropars (2012a) Exposed zone Maintenance of 38 add sub- 52 $ / linear meter Grosse Roche Ropars (2012a) ballast calibrated ballast National road Smooth terrain 2 M$ / km General costs MTQ, Service des projets per unit Haute- Raising of the Raising 1,05 M$ / km Haute-Gaspésie MTQ Service des projets Gaspésie route Ballasting D5- 1000 mm 58$ per cubic meter Ste-Anne-des Ropars (2013a) Monts
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Unit costs* Sources and Region Types of work Variants Territory Retained unit costs references** Chaleur Concrete seawall 5 M $/ linear meter Bonaventure MTQ (cost per unit of Bay with deflector the wall) d50 900 mm 3 M$ / km Gaspésie MTQ New Carlisle, Ballasting Services projets Îles-de-la- 4 K $ du linear meter Imported rocks Roche, Ropars inc and Ballasting Madeleine (N.S.) Groupe Lasalle (2011) Ballasting with big 8 K $ / linear meter Imported rocks Roche, Ropars inc and rocks (N.S.) Groupe Lasalle (2011) 300 K /150 m 2 K $ linear meter IDM – works IDM Municipality Riprap completed in 2013 5,2 k linear meter IDM estimated Roche, Ropars inc and Riprap costs Groupe Lasalle (2011) All the 50 M $ / 13 km 3,8 M $ / km Preliminary Mégantic (preliminary Railway regions estimation estimation project estimation) 6,3 M $ / km International projects, Railway Source: internet * The estimate of unit costs is mainly based on the cost of materials (transported) and their implementation. Expropriation costs are not included in these values. These estimates represent a general idea of the overall costs for each type of work in each region. ** Additional references consulted: BPR, Ropars and DDA, 2014; Ropars, 2010, Ropars, 2012c, Ropars, 2013b, Magazine Constas- Infrastructures, 2010.
2.5.4 Property assessment of developed and undeveloped land
In the case of developed land, the assumption is that when a main building is affected, the land associated with the building is considered non- buildable and thus loses all of its value on the market. The property value of the land is therefore always included in the value associated with each main building lost. This assumption is considered acceptable at this scale of analysis even if in some cases a residual value could be attributed to portions of land for uses other than habitation.
With regard to undeveloped land, the assumption is that there is loss of land when the centroid of the land is affected. Because the centroids on the graphic registers provided by the MAMOT are located in the centre of undeveloped lands, the land value of undeveloped land is considered null when around 50% of the land is eroded. Here again, there is potentially a slight overestimation considering that the non-eroded portions of undeveloped land can retain their value for purposes other than habitation. However, this overestimation is offset by land area losses were less than 50% of the land was affected and these were not included in the estimate.
Lastly, considering that the graphic registers obtained from the MAMOT do not cover the entire territory of study, a comprehensive calculation of land areas lost annually could not be done.
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3. OVERVIEW OF THE EXPOSURE OF BUILDINGS, ROADS AND RAILWAYS IN MARITIME QUEBEC
3.1 General overview
The problem of coastal erosion has long been known in maritime Quebec, but no overall assessment of the exposure of buildings, land and transport infrastructure had been made to date at such a precise degree of resolution. These preliminary results reflect the erosion process and its severity, which can vary spatially depending on the particularities of each homogeneous geomorphological unit. Although coastal erosion cannot be fully attributed to climate change, the figures presented here reflect processes exacerbated by global warming. The accelerated rise in relative sea level, reduced ice cover on the St. Lawrence and the increased frequency of winter thaw have the effect of changing coastal dynamics of low-lying coasts and cliffs and amplify coastal erosion in sensitive areas.
In total, more than 1.5 billion dollars in buildings, land and transport infrastructure will be affected by coastal erosion from 2015 to 2065 (table 8), if no adaptation solutions are implemented. Discounted to 4%, this amount represents 827 million in 2012 dollars (Appendix 1). In detail, this represents 4848 residential, 184 service, 158 commercial, and 38 industrial buildings, and 198 buildings of undetermined use, for a total value of $732 million (table 8). Close to 320 km of road and rail segments will be exposed during the same period. More specifically, this represents 154 km of municipal roads, 138 km of national roads, 3 km of highway and 26 km of railways with a total value of $776 million. In addition, there are 1346 undeveloped land areas that will be eroded by at least 50% by 2065. These land areas have a value of $15.5 million based on the property assessment adjusted to 2012 dollars (table 8). The economic values discounted at 2%, 4% and 6% are presented in Appendix 1 (see Section 2.5.1 for explanations).
The map in figure 3 provides a visual of the spatial distribution of the values obtained. Costs were observed to be higher on the southern coast of St. Lawrence than on the northern coast. The RCM of Haute-Gaspésie shows the highest value of potential losses ($294 million) followed by the RCMs of Rimouski-Neigette ($131 million), Avignon ($111 million), Îles-de-la- Madeleine ($107 million), Rocher-Percé ($104 million) and Rivière-du-Loup ($96 million). Despite their vast coastal territory, the value of exposed infrastructure in the RCMs of Haute-Côte-Nord and Minganie is lower.
Sections 3.2 and 3.3 provide a more precise picture by type of building and infrastructure.
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Table 8. Overall picture of the exposure of buildings, undeveloped land and transport infrastructure in maritime Quebec by 2065 with and without safety margins
Number or length (km) of Total economic value exposed elements (millions $)* Without With margin Without With margin margin margin Residential buildings 3521 4848 436,3 609,7 Industrial buildings 28 38 11,5 13,1 Commercial buildings 96 158 26,1 61,9 Service buildings 126 184 28,5 47,1 Buildings with undetermined use 125 198 Not available Not available TOTAL Buildings 3896 5426 502,4 731,8 Undeveloped land 919 1346 9,7 15,5 Highway (km) 2,6 2,9 14,9 16,6 National highway (km) 103,4 137,5 379,1 467,8
Municipal and local roads (km) 111,2 153,7 126,0 181,2 Railways (km) 19,1 25,7 79,6 109,9 TOTAL Roads and railways (km) 236,3 319,7 599,7 775,6
GENERAL TOTAL (millions $) 1111,8 1522,9 * 2012 dollars. See values with discount rates of 2%, 4% and 6% in Appendix 1
Figure 3. Spatial distribution of costs related to the exposure of buildings, land areas and transport infrastructure in maritime Quebec by 2065
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3.2 Buildings
The overall picture including safety margins indicates that 5426 buildings will be exposed by 2065 if no adaptation solution is implemented, for a total cost estimated at $732 million (table 8). The residential use class largely dominates the picture with 4848 buildings exposed. Of these, 2225 are cottages or secondary homes, with a total value of $219 million. The total value of residential buildings (land included) is $610 million, or 83% of the value of all buildings exposed by 2065. Buildings of undetermined use (198), service buildings (184), commercial buildings (158) and industry (38) represent 11% of exposed buildings. They share $122 million, i.e. 17% of the total value (figure 4 and 5). For more details on the types of buildings, Appendix 2 presents a series of tables to compare the data with and without safety margins, for each RCM in maritime Quebec.
n = 5426
Figure 4. Number of buildings exposed to coastal erosion by 2065 in maritime Quebec, with and without safety margins
Figure 5. Value of buildings (land included) exposed to coastal erosion by 2065 in maritime Quebec, with and without safety margins
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The temporal distribution of the number of buildings exposed and associated losses in the short, medium and long term shows that coastal erosion is a major problem in maritime Quebec. The biggest challenge will be to manage the problem in the short-term. In fact, in the next 10 years, 2568 buildings (Figure 6), or 47% of all buildings exposed by 2065 could be affected. If nothing is done, the value of losses could amount to $355 million by 2025 (Figure 7). If the trend continues, 1521 new buildings with a total estimated value of $191 million will be exposed between 2025 and 2045 while 1337 more ($185 million) will be added between 2045 and 2065. If the increase in the number of buildings exposed and their value decreases slightly in the medium and long term, the challenges remain significant as the number of buildings affected could easily double between 2025 and 2065 and reach an estimated sum of $732 million in cumulative losses (figure 6 and 7).
Figure 6. Number of buildings exposed by 2025, 2045 and 2065 for maritime Quebec, with and without safety margins
Figure 7. Value of buildings (land included) in 2025, 2045 and 2065 for maritime Quebec, with and without safety margins
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The Bas-Saint-Laurent will be the most affected region, with a total of 2210 buildings exposed by 2065 at an estimated cost of $384 million (figure 8 and Figure 9). The high population density in coastal areas and the presence of major economic centres like La Pocatière, Rivière-du-Loup, Rimouski and Matane, means that development pressure along the coasts is higher than in the other two study areas. Conversely, population scattered throughout a vast coastal territory explains in part why there are a smaller number of buildings exposed in the regions of the Côte- Nord and Gaspésie/Îles-de-la-Madeleine. Nevertheless, 1810 buildings valued at $184 million will be exposed by 2065 on the Côte-Nord, while in Gaspésie/Îles-de-la-Madeleine, 1406 buildings valued at a total of $163 million will be exposed by 2065 (figure 8 and 9).
n = 5426
Figure 8. Number of buildings exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins
Figure 9. Value of buildings exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins
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In a short-term perspective, the problem is the most significant in the Bas-Saint-Laurent. In fact, 1268 buildings totalling $222 million will be exposed to erosion by 2025 in this region (figure 10 and 11). If the trend continues, 536 new buildings with a total estimated value of $91 million will be exposed between 2025 and 2045, while 406 more with a total value of $72 million will be added between 2056 and 2065. This means that in 2065, the figures may be doubled compared to 2025 and reach more than $384 million in accumulated losses (Figure 11). In the Gaspésie and Îles-de-la-Madeleine, the number of buildings and their value are relatively significant by 2025, and also tend to diminish for the periods to follow (Figures 10 and 11). Cumulatively, the number and value of buildings could double by 2065, increasing from 698 to 1406 buildings for a total value of $163 million (Figure 10 and 11). On the Côte-Nord, more consistency is seen between the three time horizons (Figure 10). With 602 buildings identified as potentially exposed, at a value of $49 million by 2025, the cumulative number could triple by 2065, when 1810 buildings at a value of $184 million may be exposed.
Figure 10. Number of buildings exposed (land included) in 2025, 2045 and 2065 by administrative region, including the safety margin
Figure 11. Value of buildings exposed (land included) in 2025, 2045 and 2065 by administrative region, including the safety margin
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Figure 12 shows the details of the types of buildings exposed by 2065 for each of the three regions of maritime Quebec. In addition, Figures 13 and 14 provide a comparison of the 16 RCMs by showing the number and value of the buildings exposed in each, and the map in Figure 15 shows the spatial distribution.
In the Bas-Saint-Laurent, 96% of buildings exposed and 87% of the losses are associated with residential buildings (Figure 12). The other classes, such as industrial, commercial, and service buildings, and buildings of undetermined use, only represent 13% of the estimated value for the same period, i.e. a total value of $49 million. It should be noted that the residential buildings in this area consist mainly of 1134 secondary homes, compared to 878 primary residences. The RCM of Rimouski-Neigette has the highest number of exposed buildings (527) and the highest loss value ($96 million) (Figures 13 and 14). The RCM of Les Basques has the 2nd highest number of buildings exposed, with 456. However, the value of these is estimated at close to $40 million, which ranks this RCM last among those at this level in the Bas-Saint-Laurent. The RCM of Matanie stands out in terms of commerce. In fact, 15 buildings representing a total value of over $24 million are found here (Appendix 2).
On the Côte-Nord, the picture is proportionally similar to the Bas-Saint-Laurent. Here, 94% of exposed buildings and 93% of losses are associated with residential buildings (Figure 12). The other classes, such as industrial, commercial, and service buildings, and buildings of undetermined use, only represent 7% of the estimated value for the same period, i.e. a total value close to $13 million. Here, however, the number of primary residences (915) is higher than secondary homes (626). Buildings exposed on the Côte-Nord are mainly concentrated in the RCMs of Manicouagan and Sept-Rivières (figure 15). In fact, the RCM of Manicouagan ranks 1st among maritime Quebec RCMs for the number of buildings exposed by 2065, with 740. It also ranks 5th in terms of total value of losses with more than $61 million. The RCM of Sept-Rivières ranks 3rd in Quebec for the number of buildings exposed, at 505, and ranks 2nd in value of losses, with a total of $76 million. The same two RCMs also stand out in terms of service type buildings exposed by 2065. In this case, 51 service buildings (5% of buildings) will potentially be exposed by 2065 in both RCMs, representing a total of nearly $10 million in losses (Appendix 2). The presence of the two main cities of the Côte-Nord (Baie-Comeau and Sept-Îles), the intensity of retreat rates in these two regions and the presence of large areas of clay cliffs partly explain this finding. The other two RCMs, the Haute-Côte-Nord and Minganie, have diametrically opposed results. These two RCMs rank 14th and 15th out of the 16 RCMs in terms of loss values (Figures 13 and 14). Low land use as a result of low population in these two RCMs explains this result.
In the Gaspésie and Îles-de-la-Madeleine, residential class buildings dominate, but not as sharply as in the other two regions (Figure 12). However, 72% of the buildings exposed and 63% of the losses are associated with the residential sector. As on the Côte-Nord, primary residences dominate with 561 compared to 365 secondary homes. Industrial, commercial and service buildings and buildings of non-specific use represent 28% of the number of buildings exposed and 37% of the value of estimated losses for the same period. The total of these four categories amounts to a total value of $60 million, which is equivalent to the other two regions combined in terms of value. The exposed buildings are spread out relatively evenly in each RCM, except in the RCM of Haute-Gaspésie where only 121 buildings will potentially be exposed by 2065 (figure 14). This is almost two times less than in each of the four other RCMs in the region. Thus, Haute- Gaspésie has the lowest losses to coastal erosion of the 16 RCMs in maritime Quebec, i.e. approximately $9 million by 2065 (figure 14). The low population in this MRC, combined with
25 high development constraints due to the rugged terrain and the presence of long embankments of coastal road between the small municipalities in this sector partly explain this finding. In terms of commercial and service buildings, the RCM of Côte-de-Gaspé is the most affected with 47 buildings exposed by 2065 (Appendix 2). Potential losses are estimated at $18 million. The RCM of Rocher-Percé has 48 commercial and service buildings potentially exposed by 2065, at a total of near of $13 million. In Îles-de-la Madeleine, there are 39 commercial and service buildings exposed in the same period, with losses estimated at $9 million. There are also 8 industrial buildings exposed by 2065, with a value close to $5 million. Thus, 69% of the commercial, service and industrial buildings in Gaspésie/Îles-de-la-Madeleine potentially exposed by 2065 are found in these three RCMs. Lastly, 181 buildings of undetermined use are recorded in this region. These are mostly secondary buildings located on the same grounds as a main building with its own property assessment, or to recent construction without a property assessment and without a type of use. For these reasons, no value was given to them and, consequently, their number is indicated only for information purposes.
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Figure 12. Number and value of buildings (land included) exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins
27
Figure 13. Number of buildings exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins
Figure 14. Value of buildings (land included) exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins
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Figure 15. Value of buildings (land included) exposed to coastal erosion by 2065 including the safety margin, in maritime Quebec
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3.3 Roads and railways
The overall picture including safety margins indicates that 320 km of infrastructure (294 km of roads and 26 km of railways) will be exposed by 2065, representing a total cost of $775.6 million. The municipal and local roads exposed dominate with 154 km, closely followed by national roads with 138 km (
figure 16). However, the estimated cost of exposed national highways is significantly higher at $468 million compared to $181 million for municipal and local roads (Figure 17). To a lesser extent, 3 km of Highway 20 will be exposed by 2065, at a cost of close to $17 million. Railways account for 26 km of exposed segments, which represents a potential cost of $110 million. For additional details on types of infrastructure, Appendix 3 presents a series of tables that compare the data with and without safety margins for each RCM in maritime Quebec.
Figure 16. Length of roads and railways exposed to coastal erosion by 2065 for maritime Quebec, with and without safety margins
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Figure 17. Estimated cost of roads and railways exposed to coastal erosion by 2065 for maritime Quebec, with and without safety margins
Gaspésie/Îles-de-la-Madeleine is the most affected region with a total of 172 km of roads and railways exposed (figure 18), for a cost of $609 million (Figure 19). The national highway that runs along the north of the Gaspésie and the railway in Chaleur Bay are mainly responsible for these high figures. The Bas-Saint-Laurent region is next, with a total length of 88 km of infrastructure and a cost of $109 million. The Côte-Nord comes in third, but nevertheless includes 60 km of exposed infrastructure at a total estimated cost of $58 million.
Figure 18. Length of roads and railways exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins
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Figure 19. Estimated cost of roads and railways exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins
Figure 20 shows the types of infrastructure exposed by 2065 for each of the three regions in maritime Quebec In addition, Figures 21 and 22 provide a comparison of the 16 RCMs by showing the length and value of the exposed infrastructure in each, and the map in Figure 23 shows the spatial distribution.
In the Bas-Saint-Laurent, municipal and local roads dominate with close to 65 km of roads exposed at a cost of nearly $62 million (Figure 20). These roads are well spread out throughout the territory. Highway 132 ranks second with 17 km for a total cost of $23 million; the exposed segments are primarily located in the RCMs of La Mitis and La Matanie (Appendix 3). The Bas- Saint-Laurent is the only region in which a freeway is exposed. The 3 kilometers of freeway exposed are located in Rivière-du-Loup and La Pocatière, and represent an estimated cost of nearly $17 million (Appendix 3). The exposed railway entails a cost of $8 million and is located in Rimouski-Neigette (3 km), and includes two other small segments in Notre-Dame-des-Neiges and Rimouski.
On the Côte-Nord, the exposure of Highway 138 entails the highest cost by 2065, with more than $29 million for nearly 20 km of highway (Figure 20). Municipal and local roads follow closely with an estimated cost of $ 26 million, but represent twice the distance with 40 km of road. The roads exposed on the Côte-Nord are primarily located in the RCMs of Haute-Côte- Nord and Manicouagan (Figures 21 and 22). Lastly, the exposed railway includes a small 500 m segment at Baie-Comeau and represents an estimated cost of just over $2 million (Appendix 3).
In the Gaspésie and Îles-de-la-Madeleine, national highways largely dominate, with more than 100 km of exposed segments for an estimated cost of $416 million (Figure 20). The RCM of Haute-Gaspésie comprises the majority of national highway segments exposed, reaching 61 km for an estimate cost of close to $274 million (Appendix 3). The road linking Sainte-Anne-des- Monts and Sainte-Madeleine-de-la-Rivière-Madeleine thus represents the most exposed economic challenge in maritime Quebec. Highway 132 is also exposed at several locations that are well spread out elsewhere in the Gaspésie. In Îles-de-la-Madeleine, 10 km of Highway 199 is exposed, representing a cost of $42 million (Appendix 3).
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Municipal and local roads also represent a significant challenge in the Gaspésie and Îles-de-la- Madeleine with 50 km of exposed segments for an estimated cost of $93 million (Figure 20). In Îles-de-la-Madeleine alone, there are more than 8 km of municipal and local roads for a cost of close to $36 million (Appendix 3). In the Gaspésie, the RCM of Avignon has the greatest length of exposed municipal and local roads at close to 12 km, for an estimated cost of $21 million (Appendix 3). Several other small segments are well spread out elsewhere in the territory. The railway comprises nearly 22 km of exposed segments at an estimated cost of $99 million, making this another significant challenge in the Gaspésie. The RCM of Rocher-Percé alone comprises 12 km and the other 12 km are sparsely distributed throughout Chaleur Bay and Gaspé Bay (Appendix 3).
The RCM of Haute-Gaspésie stands out sharply with 71 km of exposed transport infrastructure at an estimated cost of close to $285 million (figure 22). This high figure is due to the presence of Highway 132 that runs along the coast. Chaleur Bay also draws attention, as potential losses in the RCMs of Avignon, Bonaventure and Rocher-Percé are estimated at $206 million (figure 22). The RCM of Avignon is at the top with a total estimated cost of $81 million. Îles-de-la- Madeleine is also among the most affected RCMs with an estimated cost of nearly $78 million by 2065 (Figure 22).
Overall, on figure 21, we see that the RCMs of Haute-Gaspésie, Manicouagan and Rocher-Percé stand out in terms of the length of exposed infrastructure, with 71 km in the first case and 27 km in the other two. However, in terms of replacement value, the RCMs of Haute-Gaspésie, d’Avignon and of Îles-de-la-Madeleine take the lead with estimated costs of $285 million, $81 million and $78 million respectively (figure 22). Lastly, the RCMs of Sept-Rivières and La Mitis are the least affected in terms of estimated losses, with costs of $4 million and $11 million, respectively.
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Bas-Saint-Laurent 70 64.5 70 61.5 60 60 49.1 50 50 46.5 40 40
30 30 22.7 17.1 14.9 16.6 20 10.1 20 12.8 6.5 8.3
Lenght of exposed 10 2.6 2.9 2.9 3.6 10
infrastructures (km) Value exposedof 0 0 Highway 20 National highways Local and municipal Railway infrastructure (millions $) Highway 20 National highways Local and municipal Railway roads roads Without safety margin With safety margin Without safety margin With safety margin
Côte-Nord 50 35 2.9 39.5 30 40 21.6 2.6 29.3 25 30 20 19.5 14.7 15 20 14.1 10 10 2.3 0.2
Lenght exposedof 5 infrastructures (km) 0.5 0.5 Value exposedof 0 0 National highways Local and municipal roads Railway infrastructure (millions $) National highways Local and municipal roads Railway
Without safety margin With safety margin Without safety margin With safety margin
Gaspésie - Îles-de-la-Madeleine 120 500 100.9 416.0 100 400 79.2 344.7 80 300 60 49.7 200 40 32.8 21.6 6.5 93.4 99.4 15.7 100 7.1
Lenght exposed of 20
infrastructures (km) Value exposedof 0 0 Routes nationales Local and municipal roads Railway infrastructure (millions $) National highways Local and municipal roads Railway
Without safety margin With safety margin Without safety margin With safety margin
Figure 20. Length and estimated cost of roads and railways exposed to coastal erosion by 2065 for each region of maritime Quebec, with and without safety margins
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Figure 21. Length of roads and railways exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins
Figure 22. Estimated cost of roads and railways exposed to coastal erosion by 2065 for each RCM in maritime Quebec, with and without safety margins
35
Figure 23. Overview of the exposure of roads and railways by 2065 including the safety margin, for each RCM in maritime Quebec
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3.4 Discussion on the exposure of roads
As mentioned in the introduction, the exposure of national highways to coastal erosion and submersion in Eastern Quebec was evaluated by Drejza et al. (2014b). This study, carried out in collaboration with the Quebec Ministry of Transportation, shows that 109 km of national highways will be exposed to coastal erosion by 2060. For the same territory, this study shows that 140 km of national highways (including Highway 20) will be exposed by 2065 (Table 8). Although the horizon differs by 5 years, the difference of more than 30 km raises questions. In addition, the results differ among regions, being higher in the Bas-Saint-Laurent and in the Côte- Nord, and much lower in Gaspésie/Îles-de-la-Madeleine (Table 9).
Table 9. Comparison of the results of this study on the exposure of national highways with the study by Drejza et al. (2014)
This study Drejza et al. (2014) Exposed national highways by 2065 Exposed national highways by 2060 Length (km) Length (km) Bas-Saint-Laurent 19.9 31.2 Kamouraska 0.3 2.1 La Matanie 7.4 14.3 La Mitis 5.0 8.1 Les Basques 0.0 0.0 Rimouski-Neigette 2.9 1.8 Rivière-du-Loup 4.3 4.9 Côte-Nord 19.5 30.5 La Haute-Côte-Nord 4.8 8.8 Manicouagan 6.9 9.9 Minganie 6.7 9.7 Sept-Rivières 1.1 2.1 Gaspésie/Îles-de-la-Madeleine 100.9 47.3 Avignon 8.2 8.0 Bonaventure 8.5 8.1 La Côte-de-Gaspé 7.0 1.8 La Haute-Gaspésie 61.0 14.4 Le Rocher-Percé 6.0 4.9 Les Îles-de-la-Madeleine 10.2 10.1 Total for the East of Quebec 140.3 109.0
Several methodological factors may explain these differences. First, the large difference seen in the RCM of la Haute-Gaspésie and, to a lesser extent, for the RCM of Côte-de-Gaspé depends on two factors. The first is that the entirety of Highway 132 that runs along the foot of the cliffs in the northern Gaspésie was considered exposed in this study, as the highway cannot be moved and existing protection works will have to be maintained. Second, because this sector has had protection works in place for a long time, no probable rate was calculated in the study by Drejza et al. (2014b) and therefore only a single extreme retreat event1 was considered in the
1 In this report, a “single extreme event retreat” refers to a maximum retreat measured for the same type of coast during a significant storm event
37
calculation of exposure. Thus, 491.7 km of roads located along a 500 m strip of coast have undetermined exposure in the study by Drejza et al. (2014b) due to the absence of coastal erosion data. For example, for the RCMs of Haute-Gaspésie and Côte-de-Gaspé, more than 75% of the roads located along the 500 m strip have no data. In the current study, in the absence of data for a given segment, a probable rate was nevertheless calculated using LDGIZC monitoring stations between 2000 and 2012, based on an average per type of coast in a homogeneous region. These segments represent 24% of the coasts (See section 2.1.3). It is therefore plausible that the length of exposed road would be longer compared to the study by Drejza et al. (2014b).
In the regions of the Bas-Saint-Laurent and the Côte-Nord, the situation is reversed: the results of this study are lower than Drejza et al. (2014b) (Table 9). The main reason is the difference between the safety margins used in the two studies, particularly with respect to beach terraces. Drejza et al. (2014b) used a single extreme retreat event for each type of coast, specific to each region. These data were measured following storm events as part of the coastal erosion monitoring system of the UQAR’s Laboratoire de dynamique et de gestion intégrée des zones côtières (Coastal Zone Dynamics and Integrated Management Laboratory). In the Bas-Saint- Laurent, these retreat values vary between -8.4 m and -12.8 m for beach terraces that make up 42% (206 km) of the coasts in the region. On the Côte-Nord, the single extreme retreat event measured is 12.05 m for beach terraces, which make up 18% (306 km) of the coasts. All of the road segments located within this margin are therefore considered exposed. In the current study, because the territory covered was not limited to road infrastructure, a fixed margin of 5 m was established for all low-lying coasts (see Section 2.5.1), which greatly reduces the length of road exposed. In the RCMs of La Mitis and La Matanie, the significant difference in exposed road in the two studies is linked to the presence of Highway 132 that runs along the ocean on the beach terraces. The probable rates are low in this sector and the difference in the width of the safety margin in the two studies has a significant impact on the length of road exposed.
The last factor that may explain the difference in the length of exposed road in the two studies is the segment length used to calculate exposure, which is 10 m in this study and 100 m in the study by Drejza et al. (2014b). Thus, when a portion of a 100 m segment is affected, the entire section is considered exposed. Considering that there is 1250 km of national highway at less than 500 m from the coast in Eastern Quebec, the difference in the length of road segments exposed to erosion between the two studies is relatively low.
38
5. CONCLUSION
This study is the first economic evaluation of the potential impact of coastal erosion in maritime Quebec in the context of climate change. The overall assessment by 2065 indicates a cost of $1.5 billion in 2012 dollars, taking current buildings ($732 million), land ($15.5 million) and transport infrastructure ($776 million) into account. The accelerated pace of coastal erosion, particularly on the Côte-Nord, and especially the densely built-up environment constructed close to the shoreline or the coastline in the Bas-Saint-Laurent, explain the scope of the problem to a large extent. The analysis highlights the importance of the exposure of buildings in the short term, which in several regions represent nearly 50% of all buildings exposed by 2025, less than ten years from now. Residential buildings represent by far the most significant values at risk in all regions, representing 83% of all buildings exposed by 2065. However, in Gaspésie-Îles-de-la- Madeleine, many commercial and service buildings are also exposed.
The results on the exposure of buildings, land and transport infrastructure are based on a high- resolution analysis, but given the size of the territory (3220 km of coastline) and the large amount of data processed (more than 5400 buildings exposed and more than 31 000 segments of transport infrastructure), uncertainty remains. In addition, the method used to analyze historical change and determine probable rates varies by studied region and data on coastal change are not available everywhere. Some extrapolations based on regional averages had to be made in some places in order to cover the whole territory. Nevertheless, rigorous validation of the data was performed to minimize these potential errors.
The economic analysis followed a rigorous method. The value of buildings and land was established from the property value adjusted to the market for the year 2012. The estimated replacement costs for roads and railways were adapted to each local context to better reflect potential costs than an extrapolated average. In addition, engineering and site supervision costs of 15% were added to the replacement costs for transport infrastructure in order to best reflect reality. While the study does not consider future construction that could be added to the exposed elements, it also does not take into account the potential establishment of coastal protection structures that may limit coastal retreat and thus reduce the exposure of buildings and infrastructure. The figures presented in this study thus reflect a sound estimate of future damage. In a more comprehensive study on the vulnerability of coastal communities to coastal hazards in the context of a changing climate, it will be necessary to take into account impacts associated to other hazards (submersion and landslides) and also to assess all of the indirect and non-material costs of social, environmental and economic impacts.
Lastly, this study provides a strong argument in favour of the preventive management of coastal risks, which would significantly limit the costs associated with coastal erosion. The implicit assumption of this analysis is that it will not be possible to build new infrastructure in areas exposed to coastal erosion by 2065. In the absence of such a policy, the total value of exposure will potentially be much higher. The issue of coastal risks should be approached using integrated coastal zone management, which takes into account regional planning, risk management and mitigation, regulatory framework, socio-economic development, and environmental monitoring of all of Quebec’s maritime coasts.
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Appendix 1. Table showing value of total discounted losses from 2015 to 2065
Undiscounted data 2 % Discount Rate 4 % Discount Rate 6 % Discount Rate With margin With margin With margin Without margin With margin Buildings (land included) 731 782 948 $ 562 704 997 $ 470 261 556 $ 244 432 522 $ 415 957 687 $ Undeveloped land 15 513 931 $ 11 687 933 $ 9 699 374 $ 4 705 647 $ 8 586 710 $ Roads 665 615 252 $ 426 687 040 $ 297 416 490 $ 232 354 408 $ 222 416 299 $ Railway 109 948 326 $ 70 481 446 $ 49 128 149 $ 35 588 217 $ 36 739 392 $ TOTAL 1 522 860 457 $ 1 071 561 415 $ 826 505 569 $ 517 080 793 $ 683 700 087 $
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Appendix 2. Chronological overview of building types (land included) exposed to coastal erosion by 2065 for each RCM, with and without safety margins
Table 1. Chronological overview of building types exposed by 2065 for each RCM in the Bas-Saint-Laurent region (with safety margin)
Residential Industrial Commercial Services Undetermined TOTAL No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) Bas-Saint-Laurent 2130 335.0 11 3.2 40 33.9 26 12.2 3 0 2210 384.4 Kamouraska 302 63.5 4 2.2 3 1.4 5 1.8 314 68.9 2015 to 2025 97 22.4 1 0.5 1 0.4 1 0.2 100 23.4 2025 to 2045 91 18.0 0.0 1 0.2 1 0.7 93 18.8 2045 to 2065 114 23.1 3 1.8 1 0.8 3 1.0 121 26.7 La Matanie 162 16.8 1 0.0 15 24.4 8 1.0 186 42.2 2015 to 2025 97 10.5 1 0.0 14 21.6 5 0.7 117 32.7 2025 to 2045 36 3.4 0.0 1 2.8 1 0.0 38 6.2 2045 to 2065 29 2.9 0.0 0.0 2 0.3 31 3.2 La Mitis 351 56.3 1 0.2 10 4.1 1 0.1 363 60.7 2015 to 2025 217 33.6 1 0.2 9 4.0 1 0.1 228 37.9 2025 to 2045 74 11.8 0.0 1 0.1 0.0 75 11.9 2045 to 2065 60 10.8 0.0 0.0 0.0 60 10.8 Les Basques 456 40.0 3 0.2 0.0 2 0.1 3 0 464 40.3 2015 to 2025 307 28.2 2 0.2 0.0 1 0.0 1 0 311 28.4 2025 to 2045 91 6.8 0.0 0.0 1 0.1 92 6.9 2045 to 2065 58 5.0 1 0.0 0.0 0.0 2 0 61 5.0 Rimouski-Neigette 527 95.6 1 0.2 11 3.9 5 6.6 544 106.3 2015 to 2025 339 58.6 1 0.2 5 2.2 2 0.4 347 61.4 2025 to 2045 102 18.9 0.0 3 0.8 3 6.1 108 25.9 2045 to 2065 86 18.1 0.0 3 0.9 0.0 89 19.0 Rivière-du-Loup 332 62.9 1 0.3 1 0.2 5 2.7 339 66.0 2015 to 2025 162 35.2 1 0.3 0.0 2 2.3 165 37.8 2025 to 2045 100 15.8 0.0 0.0 0.0 100 15.8 2045 to 2065 70 11.9 0.0 1 0.2 3 0.3 74 12.4
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Table 2. Chronological overview of use types for buildings exposed by 2065 for each RCM in the Bas-Saint-Laurent region (without safety margin)
Residential Industrial Commercial Services Undetermined TOTAL No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) Bas-Saint-Laurent 1580 248.4 9 3.2 19 9.5 16 10.5 3 0 1627 271.6 Kamouraska 235 49.6 4 2.2 3 1.4 4 1.5 0 246 54.7 2015 to 2025 81 19.0 1 0.5 1 0.4 1 0.2 0 84 20.0 2025 to 2045 98 19.5 0.0 1 0.2 1 0.7 0 100 20.3 2045 to 2065 56 11.1 3 1.8 1 0.8 2 0.6 0 62 14.3 La Matanie 53 4.5 0.0 4 3.7 2 0.3 0 59 8.4 2015 to 2025 29 2.3 0.0 3 0.9 2 0.3 0 34 3.4 2025 to 2045 22 2.0 0.0 1 2.8 0.0 0 23 4.8 2045 to 2065 2 0.2 0.0 0.0 0.0 0 2 0.2 La Mitis 156 23.6 1 0.2 3 1.0 0.0 0 160 24.8 2015 to 2025 119 17.2 1 0.2 3 1.0 0.0 0 123 18.5 2025 to 2045 31 5.1 0.0 0.0 0.0 0 31 5.1 2045 to 2065 6 1.2 0.0 0.0 0.0 0 6 1.2 Les Basques 386 33.6 2 0.2 0.0 2 0.1 3 0 393 33.9 2015 to 2025 260 23.7 2 0.2 0.0 1 0.0 1 0 264 23.8 2025 to 2045 91 6.5 0.0 0.0 1 0.1 0 92 6.6 2045 to 2065 35 3.4 0.0 0.0 0.0 2 0 37 3.4 Rimouski-Neigette 471 84.7 1 0.2 9 3.5 4 6.0 0 485 94.4 2015 to 2025 329 56.9 1 0.2 5 2.2 2 0.4 0 337 59.8 2025 to 2045 104 19.8 0.0 3 0.8 2 5.6 0 109 26.2 2045 to 2065 38 8.0 0.0 1 0.4 0.0 0 39 8.4 Rivière-du-Loup 279 52.5 1 0.3 0.0 4 2.6 0 284 55.4 2015 to 2025 140 29.9 1 0.3 0.0 2 2.3 0 143 32.6 2025 to 2045 102 16.5 0.0 0.0 1 0.2 0 103 16.7 2045 to 2065 37 6.0 0.0 0.0 1 0.1 0 38 6.1
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Table 3. Chronological overview of use types for buildings exposed by 2065 for each RCM in the Côte-Nord region (with safety margin)
No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) Côte-Nord 1700 171.7 4 1.4 27 1.8 65 9.6 14 0 1810 184.4 La Haute-Côte-Nord 281 21.3 0.0 3 0.7 8 0.3 292 22.4 2015 to 2025 162 12.1 0.0 2 0.4 5 0.2 169 12.7 2025 to 2045 68 5.2 0.0 1 0.3 0.0 69 5.5 2045 to 2065 51 4.1 0.0 0.0 3 0.1 54 4.2 Manicouagan 692 55.1 2 0.4 19 0.5 17 5.4 10 0 740 61.4 2015 to 2025 222 14.1 1 0.2 2 0.0 4 1.2 2 0 231 15.5 2025 to 2045 257 21.9 0.0 13 0.4 5 1.0 5 0 280 23.3 2045 to 2065 213 19.1 1 0.2 4 0.1 8 3.2 3 0 229 22.6 Minganie 262 22.9 2 1.0 3 0.4 6 0.2 273 24.4 2015 to 2025 76 6.5 2 1.0 3 0.4 2 0.0 83 7.9 2025 to 2045 89 7.3 0.0 0.0 1 0.0 90 7.4 2045 to 2065 97 9.0 0.0 0.0 3 0.2 100 9.2 Sept-Rivières 465 72.4 0.0 2 0.2 34 3.6 4 0 505 76.2 2015 to 2025 99 11.5 0.0 0.0 17 1.4 3 0 119 12.9 2025 to 2045 184 28.3 0.0 1 0.2 8 0.9 1 0 194 29.4 2045 to 2065 182 32.6 0.0 1 0.0 9 1.3 192 33.9
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Tableau 4. Chronological overview of use types for buildings exposed by 2065 for each RCM in the Côte-Nord region (without safety margin)
Residential Industrial Commercial Services Undetermined TOTAL No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) Côte-Nord 1290 127.5 4 1.4 24 1.4 50 4.7 12 0 1380 135.0 La Haute-Côte-Nord 190 13.1 0.0 3 0.7 6 0.3 0 199 14.1 2015 to 2025 126 8.8 0.0 2 0.4 5 0.2 0 133 9.4 2025 to 2045 54 3.7 0.0 1 0.3 0.0 0 55 4.0 2045 to 2065 10 0.6 0.0 0.0 1 0.0 0 11 0.6 Manicouagan 515 38.8 2 0.4 17 0.5 12 2.3 8 0 554 42.0 2015 to 2025 206 12.8 1 0.2 2 0.0 3 0.6 2 0 214 13.6 2025 to 2045 223 19.0 1 0.2 13 0.4 6 1.1 5 0 248 20.7 2045 to 2065 86 7.0 0.0 2 0.0 3 0.6 1 0 92 7.6 Minganie 212 18.8 2 1.0 2 0.1 4 0.1 0 220 19.9 2015 to 2025 75 6.5 2 1.0 2 0.1 2 0.0 0 81 7.6 2025 to 2045 89 8.1 0.0 0.0 0.0 0 89 8.1 2045 to 2065 48 4.2 0.0 0.0 2 0.1 0 50 4.3 Sept-Rivières 373 56.9 0.0 2 0.2 28 2.0 4 0 407 59.1 2015 to 2025 88 9.5 0.0 0.0 16 1.4 3 0 107 11.0 2025 to 2045 181 28.4 0.0 1 0.2 7 0.5 1 0 190 29.1 2045 to 2065 104 19.0 0.0 1 0.0 5 0.0 0 110 19.0
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Table 5. Chronological overview of use types for buildings exposed by 2065 for each RCM in the Gaspésie/Îles-de-la-Madeleine region (with safety margin)
No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) Gaspésie/ 1018 102.9 23 8.5 91 26.1 93 25.4 181 0 1406 163.0 Îles-de-la-Madeleine Avignon 244 25.5 1 0.1 4 3.1 4 0.4 54 0 307 29.1 2015 to 2025 136 13.4 0.0 1 0.4 3 0.4 29 0 169 14.2 2025 to 2045 65 7.4 0.0 2 2.4 1 0.1 11 0 79 9.9 2045 to 2065 43 4.6 1 0.1 1 0.3 0.0 14 0 59 5.0 Bonaventure 139 20.5 2 0.5 11 3.3 13 2.3 73 0 238 26.7 2015 to 2025 54 8.3 1 0.0 6 2.6 7 1.0 39 0 107 11.9 2025 to 2045 41 4.2 1 0.5 4 0.7 4 1.0 26 0 76 6.4 2045 to 2065 44 8.1 0.0 1 0.1 2 0.3 8 0 55 8.4 La Côte-de-Gaspé 169 15.1 4 1.4 24 8.7 23 9.2 2 0 222 34.4 2015 to 2025 86 7.1 2 0.9 17 6.4 16 8.0 1 0 122 22.4 2025 to 2045 45 4.9 2 0.5 4 0.9 1 0.0 52 6.4 2045 to 2065 38 3.1 0.0 3 1.4 6 1.2 1 0 48 5.6 La Haute-Gaspésie 100 6.0 3 0.7 13 2.0 5 0.7 121 9.3 2015 to 2025 30 1.6 1 0.5 5 0.6 1 0.0 37 2.7 2025 to 2045 27 1.3 1 0.1 4 0.7 2 0.5 34 2.5 2045 to 2065 43 3.2 1 0.1 4 0.7 2 0.2 50 4.2 Le Rocher-Percé 196 20.6 5 1.2 20 6.5 28 6.2 7 0 256 34.4 2015 to 2025 82 8.2 4 1.1 14 4.8 21 3.5 4 0 125 17.6 2025 to 2045 57 6.0 1 0.0 4 1.4 3 0.4 3 0 68 7.9 2045 to 2065 57 6.3 0.0 2 0.2 4 2.4 63 8.9 Les Îles-de-la-Madeleine 170 15.3 8 4.6 19 2.6 20 6.6 45 0 262 29.0 2015 to 2025 82 6.2 3 2.4 13 1.6 14 5.4 26 0 138 15.6 2025 to 2045 59 5.3 1 1.5 1 0.1 2 0.1 10 0 73 7.1 2045 to 2065 29 3.7 4 0.7 5 0.8 4 1.0 9 0 51 6.3
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Tableau 6. Chronological overview of building types exposed by 2065 for each RCM in the Gaspésie/Îles-de-la-Madeleine region (without safety margin)
Residential Industrial Commercial Services Undetermined TOTAL No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) No. of build. Value (M$) Gaspésie- 651 60.4 15 6.9 53 15.2 60 13.4 110 0 889 95.8 Îles-de-la-Madeleine Avignon 174 18.0 1 0.1 3 2.8 3 0.4 37 0 218 21.3 2015 to 2025 113 10.7 0.0 1 0.4 3 0.4 23 0 140 11.5 2025 to 2045 52 6.3 1 0.1 2 2.4 0.0 10 0 65 8.8 2045 to 2065 9 1.0 0.0 0.0 0.0 4 0 13 1.0 Bonaventure 86 10.6 1 0.0 7 1.5 12 2.1 43 0 149 14.3 2015 to 2025 37 5.0 1 0.0 3 1.0 7 1.0 22 0 70 7.0 2025 to 2045 31 3.1 0.0 3 0.4 4 1.0 19 0 57 4.6 2045 to 2065 18 2.4 0.0 1 0.1 1 0.1 2 0 22 2.6 La Côte-de-Gaspé 75 5.9 2 1.3 17 6.4 10 4.4 0 104 18.0 2015 to 2025 45 3.6 1 0.8 12 4.5 9 4.4 0 67 13.2 2025 to 2045 23 1.9 1 0.5 3 0.7 0.0 0 27 3.0 2045 to 2065 7 0.4 0.0 2 1.3 1 0.0 0 10 1.8 La Haute-Gaspésie 56 2.9 2 0.5 7 0.7 2 0.2 0 67 4.3 2015 to 2025 19 1.0 1 0.5 4 0.4 1 0.0 0 25 1.9 2025 to 2045 26 1.2 1 0.1 3 0.2 0.0 0 30 1.5 2045 to 2065 11 0.7 0.0 0.0 1 0.2 0 12 0.9 Le Rocher-Percé 118 11.2 4 0.9 12 2.7 22 3.4 1 0 157 18.2 2015 to 2025 64 5.5 3 0.9 7 1.2 18 3.1 0 92 10.6 2025 to 2045 45 4.8 1 0.0 5 1.5 3 0.4 1 0 55 6.8 2045 to 2065 9 0.8 0.0 0.0 1 0.0 0 10 0.9 Les Îles-de-la-Madeleine 142 11.9 5 4.0 7 1.0 11 2.8 29 0 194 19.8 2015 to 2025 73 5.4 3 2.4 6 0.8 7 1.9 19 0 108 10.6 2025 to 2045 57 5.1 1 1.5 1 0.1 2 0.1 8 0 69 6.9 2045 to 2065 12 1.3 1 0.1 0.0 2 0.8 2 0 17 2.3
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Appendix 3. Overview of transport infrastructure exposed to coastal erosion by 2065 for each RCM, with and without safety margins
With safety margin Without safety margin Lenght (km) Total cost (M$) Lenght (km) Total cost (M$) Bas-Saint-Laurent 88.1 109.0 64.7 80.7 Kamouraska 15.1 15.1 14.4 14.3 Highway 20 0.3 1.7 0.3 1.4 Municipal 14.8 13.4 14.1 12.9 National 0.0 0.0 0.0 0.0 La Matanie 13.7 18.0 5.9 7.8 Municipal 6.3 6.5 2.1 2.1 National 7.4 11.5 3.9 5.7 La Mitis 11.0 11.3 6.1 6.5 Municipal 5.9 5.5 2.6 2.4 National 5.0 5.8 3.5 4.1 Les Basques 10.6 12.2 9.6 10.5 Railway 0.5 2.9 0.4 2.0 Municipal 10.1 9.3 9.2 8.5 Rimouski-Neigette 22.3 23.7 16.0 17.1 Railway 3.1 5.3 2.6 4.5 Municipal 16.2 14.9 12.4 11.4 National 2.9 3.4 1.0 1.2 Rivière-du-Loup 15.4 28.7 12.5 24.5 Highway 20 2.6 14.9 2.3 13.4 Municipal 11.1 11.9 8.6 9.2 National 1.7 2.0 1.6 1.9
With safety margin Without safety margin Lenght (km) Total cost (M$) Lenght (km) Total cost (M$) Côte-Nord 59.6 57.8 43.9 38.6 La Haute-Côte-Nord 11.5 13.9 7.1 6.0 Municipal 6.7 6.9 4.3 1.6 National 4.8 7.0 2.8 4.4 Manicouagan 26.9 22.8 22.0 17.6 Railway 0.5 2.3 0.5 2.3 Municipal 19.5 12.5 16.0 9.0 National 6.9 7.9 5.5 6.3 Minganie 14.2 17.1 9.8 12.2 Municipal 7.5 4.2 4.8 2.3 National 6.7 12.9 5.0 9.9 Sept-Rivières 7.0 4.0 5.0 2.7 Municipal 5.8 2.7 4.3 1.8 National 1.1 1.3 0.8 0.9
With safety margin Without safety margin Lenght (km) Total cost (M$) Lenght (km) Total cost (M$) Gaspésie/Îles-de-la-Madeleine 172.1 608.8 127.7 480.4 Avignon 21.5 80.9 9.7 39.3 Railway 1.7 19.4 1.5 16.8 Municipal 11.6 21.2 5.6 9.9 National 8.2 40.3 2.6 12.6 Bonaventure 16.8 56.5 10.8 33.2 Railway 3.3 27.6 2.0 15.0 Municipal 5.0 5.7 3.5 3.5 National 8.5 23.1 5.4 14.6 La Côte-de-Gaspé 18.0 41.0 10.3 22.5 Railway 4.6 10.7 3.3 7.6 Municipal 6.3 10.2 4.7 7.7 National 7.0 20.1 2.3 7.3 La Haute-Gaspésie 71.3 284.7 64.5 274.2 Municipal 10.3 10.9 6.5 6.7 National 61.0 273.8 58.0 267.5 Le Rocher-Percé 26.6 68.1 18.0 47.5 Railway 11.9 41.7 8.9 31.5 Municipal 8.6 9.6 5.9 6.4 National 6.0 16.8 3.2 9.6 Les Îles-de-la-Madeleine 18.0 77.6 14.3 63.7 Municipal 7.8 35.8 6.7 30.6 National 10.2 41.8 7.6 33.1
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