CRD – Coastal Sea Level Rise Risk Assessment
Total Page:16
File Type:pdf, Size:1020Kb
Attachment 1 to Appendix A Capital Regional District Coastal Sea Level Rise Risk Assessment Prepared by: AECOM 200 – 415 Gorge Road East Victoria, BC, Canada V8T 2W1 www.aecom.com January 2015 AECOM Capital Regional District Coastal Sea Level Rise Risk Assessment Statement of Qualifications and Limitations The attached Report (the “Report”) has been prepared by AECOM Canada Ltd. (“Consultant”) for the benefit of the client (“Client”) in accordance with the agreement between Consultant and Client, including the scope of work detailed therein (the “Agreement”). The information, data, recommendations and conclusions contained in the Report (collectively, the “Information”): • is subject to the scope, schedule, and other constraints and limitations in the Agreement and the qualifications contained in the Report (the “Limitations”); • represents Consultant’s professional judgement in light of the Limitations and industry standards for the preparation of similar reports; • may be based on information provided to Consultant which has not been independently verified; • has not been updated since the date of issuance of the Report and its accuracy is limited to the time period and circumstances in which it was collected, processed, made or issued; • must be read as a whole and sections thereof should not be read out of such context; • was prepared for the specific purposes described in the Report and the Agreement; and • in the case of subsurface, environmental or geotechnical conditions, may be based on limited testing and on the assumption that such conditions are uniform and not variable either geographically or over time. Consultant shall be entitled to rely upon the accuracy and completeness of information that was provided to it and has no obligation to update such information. Consultant accepts no responsibility for any events or circumstances that may have occurred since the date on which the Report was prepared and, in the case of subsurface, environmental or geotechnical conditions, is not responsible for any variability in such conditions, geographically or over time. Consultant agrees that the Report represents its professional judgement as described above and that the Information has been prepared for the specific purpose and use described in the Report and the Agreement, but Consultant makes no other representations, or any guarantees or warranties whatsoever, whether express or implied, with respect to the Report, the Information or any part thereof. Without in any way limiting the generality of the foregoing, any estimates or opinions regarding probable construction costs or construction schedule provided by Consultant represent Consultant’s professional judgement in light of its experience and the knowledge and information available to it at the time of preparation. Since Consultant has no control over market or economic conditions, prices for construction labour, equipment or materials or bidding procedures, Consultant, its directors, officers and employees are not able to, nor do they, make any representations, warranties or guarantees whatsoever, whether express or implied, with respect to such estimates or opinions, or their variance from actual construction costs or schedules, and accept no responsibility for any loss or damage arising therefrom or in any way related thereto. Persons relying on such estimates or opinions do so at their own risk. Except (1) as agreed to in writing by Consultant and Client; (2) as required by-law; or (3) to the extent used by governmental reviewing agencies for the purpose of obtaining permits or approvals, the Report and the Information may be used and relied upon only by Client. Consultant accepts no responsibility, and denies any liability whatsoever, to parties other than Client who may obtain access to the Report or the Information for any injury, loss or damage suffered by such parties arising from their use of, reliance upon, or decisions or actions based on the Report or any of the Information (“improper use of the Report”), except to the extent those parties have obtained the prior written consent of Consultant to use and rely upon the Report and the Information. Any injury, loss or damages arising from improper use of the Report shall be borne by the party making such use. This Statement of Qualifications and Limitations is attached to and forms part of the Report and any use of the Report is subject to the terms hereof. RPT-2015-01-26-CRD Coastal SLR Risk Assessment-60310678 FINAL.Docx AECOM Capital Regional District Coastal Sea Level Rise Risk Assessment RPT-2015-01-26-CRD Coastal SLR Risk Assessment-60310678 FINAL.Docx AECOM Capital Regional District Coastal Sea Level Rise Risk Assessment Executive Summary 1. Project Context. With global sea levels projected to continue rising, public and private assets and shoreline land uses across the Capital Regional District (CRD) have the potential to experience an increase in frequency and magnitude of periodic inundation events as well as permanent inundation. The Coastal Sea Level Rise Risk Assessment project has been developed as a first phase in CRD’s multi-year project to gather information to support future analysis and policy response for sea level rise (SLR) within the CRD. CRD is the first BC regional district to have completed mapping based on the draft provincial guidelines for floodplain mapping and intends to use the mapping and findings from this project to consult and provide feedback to the Province on the proposed guidelines, and planning for the impacts that SLR will have in the CRD region. Mapping based on provincial guidelines shows that any significant impacts from sea level rise will not be felt until 2050 or beyond, and advanced planning can be applied to help avoid or manage such impacts before they are realised. 2. Uses and Limitation. This project is the very first step to assess how the region’s shoreline may look 35, 85 and 185 years in the future. The mapping from this study considers static sea level rise, coupled with relatively extreme 1 in 500 year storm surge conditions, so while areas may be depicted within an inundation zone, this does not mean these areas will necessarily experience flooding due to sea level rise and storm surge in the future. Significant further analysis is necessary to fully understand what the effects of future sea level rise may be in these coastal areas. Establishing flood hazard boundaries is a responsibility of local government, and each municipality within the region will determine how they will respond to future sea level rise. Once future flood hazard area boundaries are established by municipalities, there are many tools that can be used to address sea level rise within these areas. These include planning and regulatory tools, land use change or restriction, structural tools including flood protection works, and non-structural tools such as soft armouring by wetland construction. Future work for specific locations should be used to confirm the data used and produced in this report. 3. Project Objectives. The primary purpose of this project was to identify and map areas that are vulnerable to SLR within the CRD. The secondary purpose was to understand the potential economic consequences of SLR, thereby providing information to support development of future policy and land use regulations. The technical scope of work to deliver these objectives was designed to align with the available project funding, and the mapping (Appendix A) and other data reporting (Appendix B) was focused on 24 key areas (“Sea Level Rise Focus Areas”) that were selected because of the relatively high levels of expected future inundation and / or the key community assets that are present in those areas. Three high-level case studies were developed to help identify the potential service disruption effects that could occur under sea level rise and storm surge conditions. These case studies were for transportation disruption (based on disruption to Highway 14 south of Shirley), local community disruption (in the Oak Bay Windsor Park residential area), and business disruption (in the Victoria Inner Harbour). 4. Approach to Mapping. The maps developed for the project show the anticipated future shoreline at high tide, and during storm surge conditions in 2050, 2100 and 2200. The mapping is based on the 2011 Province of BC Coastal Floodplain Mapping Guidelines and Specifications Report, and uses the recommended SLR levels for those time periods and 1 in 500 year storm surge conditions. A digital elevation model was developed for across the region, and then factors that will influence future sea levels were layered onto the model to give an estimation of the future shoreline. These factors include projections for static SLR, highest high water large tide (HHWLT) values collected from hydrological monitoring at over 30 sites across the region, vertical land elevation figures which address seismic activity, and the 1 in 500 year storm surge conditions. RPT-2015-01-26-CRD Coastal SLR Risk Assessment-60310678 FINAL.Docx Page i AECOM Capital Regional District Coastal Sea Level Rise Risk Assessment 5. SLR Focus Areas. Once maps were developed for the entire CRD coastline a workshop was run with the CRD Project Team to identify the key assets (e.g. key municipal infrastructure) that exist within the coastal areas that could be subject to flooding for the scenarios considered. This was used to help define SLR Focus Areas for a selection of areas with key assets and relatively high levels of expected future inundation. A set of 24 SLR Focus Areas were then defined and for each area maps were produced to show inundation levels for the different sea level rise scenarios (for 2050, 2100 and 2200, and with and without 1 in 500 year storm surge conditions). 6. Description of land and assets within each SLR Focus Area. Data were compiled to define land use, shoreline sensitivity to sea level rise, valuation of land and improvements, roads and presence of key public assets within the areas that would be flooded within the selected scenario of SLR in year 2100 plus the 1 in 500 year storm surge conditions.