Deliverable 6.3 DEMO Insurance Value Assessment - PART 7: FRANCE - Brague Amandine Gnonlonfin, Guillaume Piton, Roxane Marchal, Muhammad Badar Munir, Z.X
Total Page：16
File Type：pdf, Size：1020Kb
Deliverable 6.3 DEMO Insurance Value Assessment - PART 7: FRANCE - Brague Amandine Gnonlonfin, Guillaume Piton, Roxane Marchal, Muhammad Badar Munir, Z.X. Wang, David Moncoulon, Alexandre Mas, Patrick Arnaud, Jean-Marc Tacnet, Ali Douai To cite this version: Amandine Gnonlonfin, Guillaume Piton, Roxane Marchal, Muhammad Badar Munir, Z.X. Wang, et al.. Deliverable 6.3 DEMO Insurance Value Assessment - PART 7: FRANCE - Brague. 2019, pp.267-428. hal-03027263 HAL Id: hal-03027263 https://hal.inrae.fr/hal-03027263 Submitted on 27 Nov 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution| 4.0 International License Deliverable 6.3 DEMO Insurance Value Assessment PART 7 FRANCE - Brague Pages: 267 - 428 Should you wish to use or refer to it, please cite as follows: Gnonlonfin, A., Piton, G., Marchal, R., Munir, M. B., Wang, Z.X., Moncoulon, D., Mas, A., Arnaud, P., Tacnet, JM., & Douai, A. (2019): “DELIVERABLE 6.3 DEMO Insurance value assessment report- Part 7: France – Brague DEMO”. EU Horizon 2020 NAIAD Project, Grant Agreement N°730497 Part 7: FRANCE – Brague 267 D6.3 DEMO Insurance Value Assessment Report Part 7: FRANCE – Brague NAIAD-GA nº 730497 INDEX Chapter 1. Preliminary elements of the economic assessment ............................................. 270 1.1 Framing the analysis .................................................................................................. 270 1.2 Define and describe scenarios and strategies ........................................................... 272 Chapter 2. Assessment of Life Cycle Cost and Opportunity Costs of NBS visions .................. 321 2.1 Introduction .............................................................................................................. 321 2.2 Methodology and data .............................................................................................. 321 2.3 Results ....................................................................................................................... 324 2.4 Discussion .................................................................................................................. 326 Chapter 3. Assessment of the impact of NBS visions on avoided damages ........................... 326 3.1 Introduction .............................................................................................................. 326 3.2 Methodology ............................................................................................................. 326 3.3 Results ....................................................................................................................... 340 3.4 Discussion .................................................................................................................. 343 Chapter 4. Economic valuation of co-benefits of NBS visions ................................................ 347 4.1 Introduction .............................................................................................................. 347 4.2 Methodology and Data ............................................................................................. 348 4.3 Results ....................................................................................................................... 356 4.4 Discussion .................................................................................................................. 358 Chapter 5. Integration of the economic assessment .............................................................. 359 5.1 Cost-Benefit analysis ................................................................................................. 359 5.2 Toward multicriteria analysis .................................................................................... 360 Chapter 6. Conclusion ............................................................................................................. 366 Annexes ............................................................................................................................... 373 Part 7: FRANCE – Brague 268 D6.3 DEMO Insurance Value Assessment Report Part 7: FRANCE – Brague NAIAD-GA nº 730497 Executive Summary The Brague River basin is a 68 km² catchment located along the French Mediterranean coast between the cities of Cannes and Nice. On 3rd Oct. 2015, the basin was severely hit by an extreme flash flood (time return was over 100 years). The basin very flat lowlands experienced numerous damages and casualties related to this flooding event. The several campsites located in these areas were closed by State decision because of the flood risk but dozens of houses remain at risk. The closing of the campsite opened a window of opportunity to redefine the economic activities of the valley and the river corridor in order to improve its life, landscape and environmental quality and to decrease the flood risk. Within the NAIAD project, several teams of researchers and experts in forest and river management, natural hazards (flood, erosion, wildfire), vulnerability and damage assessment, economy and decision aid gathered to perform an in-depth study of the Brague River catchment. More precisely, we studied its peculiarities, the potential efficacy and efficiency of flood protections measures based on green or grey measures, as well as their co-benefit. NBS flood alleviation strategies studied for the Brague catchment are a combination of both retention measures by small natural retention areas in the upper catchment, along with a widening of the river corridor in the lowlands enhanced by floodplain reconnection. Floodplain works consist in several measures as bed and bridge widening, forest corridor and wetlands restoration, and large woods debris management. They are integrated in a so-called “giving- room-to-the-river” strategy. Two levels of ambition, namely high and very high, are considered as well as a more classical grey scenario based on huge retention dams. This report presents the assessment of the Basin state in term of flood risk and river quality. Total costs of the three protection strategies were evaluated. Damage related to historical events and to theoretical floods with known return period were computed in the current and projects’ situation, thus enabling to compute mean annual avoided damage. The co-benefit related to NBS strategies were also evaluated using two different methods: transfer of values based on a meta-regression-analysis of values provided in other catchments and a contingent valuation performed locally through the interview of more than 400 peoples in the basin. The cost-benefit analysis demonstrates that costs are higher than the main benefit, i.e., avoided damage, but when including co-benefit the balance may reach higher benefits than costs for NBS strategies, though not for the grey solution. It worth being stressed that several intangible criteria, e.g., the improvement of the natural status of the river, are poorly captured by the monetary methods and a complementary multicriteria decision framework was developed to handle both tangible and intangible criteria. Keywords : flash floods, large woody debris, giving room to the river, protection measure efficacy, willingness to pay. Part 7: FRANCE – Brague 269 D6.3 DEMO Insurance Value Assessment Report Part 7: FRANCE – Brague NAIAD-GA nº 730497 Chapter 1. Preliminary elements of the economic assessment 1.1 Framing the analysis The aim of this report is to perform the economic assessment of Nature Based Solutions (NBS) in the Brague Demo. The Brague is a short river, 21-km long, of the Mediterranean coast with a flash flood regime. As the Mediterranean climate promote heavy rains in autumn, the floods of the Brague are often devastating and sometimes deadly. Over the period 1970-2015, the Brague caused fourteen natural disaster floods and eight deaths. For example, the insured damages of the October, 2015 flood mount to €50 million (Pengal et al., 2017). In this context, there is a need for additional measures to reduce flooding risks of the Brague. NBS are alternative measures or complementary to tradional grey ones to water related risks management (Graveline et al., 2017). It is worth noting that NBS is a ‘catch-all’ concept with multiple definitions (Albert et al., 2019; Nesshöver et al., 2017; Cohen-Shacham et al., 2016; Eggermont et al., 2015). The concept indeed encompases several ecosystem-based concepts (Nesshöver et al., 2017; Eggermont et al., 2015) of which Catchment Systems Engineering (CSE), Ecological Engeeneering (EE) or Natural Flood Management (NFM) (Table 1). CONCEPTS DEFINITION EXEMPLE OF MEASURES ECOLOGICAL ENGINEERING EE is defined as the design of Restoration of river systems, (EE) sustainable ecosystems that etc. integrate human society with Wetlands creation, its natural environment for Agro-ecological engineering, the benefit of both (Mitsch, Wastewater wetlands, 2012, p. 5) Bio-manipulation, Soil bioremediation CATCHMENT SYSTEMS CSE is an interventionist Drain barriers