Bristol Avon Flood Strategy - supporting evidence

Closed 20 Dec 2020

Opened 5 Oct 2020

Overview

Bristol City Council, supported by the Environment Agency, began technical modelling work in 2010 to better understand the risk of flooding from the River Avon to the city. The Central Area Flood Risk Assessment investigated flood risk from the River Avon to central Bristol. The risk of this increases as the impact of climate change causes the sea levels to rise and peak river flows to increase.

Following 2014 Cabinet approval, the Council has been working with the Environment Agency and other partners to create a vital long-term strategy for managing the River Avon flood threat. Below presents all the supporting evidence.

File  Document Name  Purpose
SOC (UPDATED) 2020 Bristol Avon Flood Strategy

The Strategic Outline Case sets out the long-term plan to better protect homes and businesses in Bristol and neighbouring communities from River Avon flooding and enhance the river for all.

Updated with minor technical amendments and with Environment Agency approval.

SOC Appendix A 2020 Bristol Avon Flood Strategy - Key Plans 2020 Bristol Avon Flood Strategy key plans.
SOC Appendix B 2020 Bristol Avon Flood Strategy - Flood Maps 2020 Bristol Avon Flood Strategy flood predictions in the absence of investment for flood events with a different chance of occurring, and with different allowances for the impact of climate change. 
SOC Appendix C 2020 Bristol Avon Flood Strategy – Indicative Defences by Reach 2020 Bristol Avon Flood Strategy plans showing the potential extent of defences, subject to consultation and design.
SOC Appendix D 2020 Bristol Avon Flood Strategy – Placemaking Opportunities Report 2020 Bristol Avon Flood Strategy report builds on work to date to explores the potential aspirational opportunities for placemaking and wider benefits.
SOC Appendix E 2020 Bristol Avon Flood Strategy – Shortlist Options Summary Appraisal 2020 Bristol Avon Flood Strategy Shortlist Qualitative Appraisal Table summarises the strategic options appraisal from the 2017 study.
SOC Appendix F 2020 Bristol Avon Flood Strategy  – Phase 1 Build Out Priority Assessment 2020 Bristol Avon Flood Strategy assessment to prioritise the build order for discrete elements of Phase 1.
SOC Appendix G 2020 Bristol Avon Flood Strategy  – Updates to proposed defences 2020 Bristol Avon Flood Strategy report summarising the proposed defences assumed for strategic budget estimates. The report builds on the 2017 study.
SOC Appendix H 2020 Bristol Avon Flood Strategy  – Economic Appraisal Technical Report 2020 Bristol Avon Flood Strategy report outlining the economic appraisal for a Strategic Outline Case for the Bristol Avon Flood Strategy.
SOC Appendix I Bristol Flood Strategy Overview of Flood Modelling An overview of the flood modelling to support the Strategy.
SOC Appendix J Bristol Flood Strategy Initial Whole Life Carbon Assessment An initial whole-life carbon assessment to support the SOC.
0.1 Bristol’s Historic Tidal Flood Chronology Chronology of tidal flooding in Bristol (historical records between 1483 and 1990).
0.2

Heritage Assessment

Documents key aspects of the historic environment along the river corridor. Identifies the opportunities that the historic landscape presents in terms of making a quality resilient place for the future.
0.3 New Cut Greenway Place Concept An initial proof of concept place vision from Netham Lock to Entrance Lock on both sides of the New Cut. Provides detailed analysis, including the definition of character areas and opportunities and constraints diagrams.
0.3.1 Green Infrastructure Valuation Estimate Indicative value and long-term beneficial impact of green infrastructure from Netham Lock to Entrance Lock on both sides of the New Cut.
1.0 (UPDATED) Non-Technical Summary for the Strategic Environmental Assessment Addendum

Non-technical summary of environmental report prepared to identify, describe and evaluate the likely significant effect of the Bristol Avon Flood Strategy on environmental factors; suggest measures by which any adverse effects could be mitigated; make recommendations to improve the environmental performance; and provide an opportunity for statutory consultees and interested parties to offer views on any aspect of the SEA process.

Updated with amendments following consultation.

1.1 (UPDATED) Strategic Environmental Assessment Addendum

An update to the Strategic Environmental Assessment (SEA) Environmental Report previously prepared in 2017. The Addendum largely builds on the 2017 SEA to consider updates to the preferred option.

Updated with amendments following consultation.

1.1 App B Statement to Inform an Appropriate Assessment

An update to the Strategic Environmental Assessment (SEA) Environmental Report.

Report to inform the assessment of the potential for effects on European Sites from the implementation of the proposed works, as required by Regulation 63 of the Habitats Regulations.
1.1 App C Preliminary WFD Assessment

An update to the Strategic Environmental Assessment (SEA) Environmental Report.

Assessment to identify potential impacts that could cause deterioration in the ecological status of a water body or that could prevent the water body from meeting its WFD objectives.
1.1.1 Consideration of Coastal Habitat Loss Technical Note Technical note specifically provides consideration of coastal squeeze and habitat loss in relation to this the proposed works of this amended Strategy.
1.2 Strategic Environmental Assessment: Environmental Report

Strategic Environmental Report prepared to support the 2017 Study into strategic approach to manage tidal flood risk to Bristol.

Bristol City Council chose to subject the plans to Strategic Environment Assessment on a voluntary basis so that we could better understand any impacts of the proposed strategy.
2.1

2017 Tidal Flood Strategy

2017 Study into strategic approach to manage tidal flood risk to Bristol. The study followed the Environment Agency’s strategic appraisal process whereby the technical, economic, environmental and social merits of a range of strategic options were assessed. The study established preliminary strategic approach design, economic appraisal, environmental appraisal and strategic environmental assessment information.
2.2.1 2017 Tidal Flood Strategy - Baseline Review Briefing Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Sets out the key findings from an initial review of previous work. It also sets out the project and option appraisal objectives and highlights the key baseline information required.
2.2.1.1 2017 Tidal Flood Strategy - Hydraulic Modelling Review Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Presents the findings of a hydraulic model review. Assessed the suitability of the existing model.
2.2.1.2 2017 Tidal Flood Strategy – Defacto Flood Defence Investigation Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Details a visual condition assessment to estimate of the likely depth of water that identified buildings, walls and other raised structures can resist.
2.2.1.3 2017 Tidal Flood Strategy - Environmental Baseline Review Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Desk-based review of environmental data. Report also identifies potential key constraints or opportunities [Note Appendix D excluded as confidential data].
2.2.2 2017 Tidal Flood Strategy - Long List Options – Briefing Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Sets out the long list of options and next steps in the options appraisal process. Each strategic option outlines a sequence of measures to be implemented in the short, medium and long term.
2.2.2.1 2017 Tidal Flood Strategy - Economic Baseline Briefing Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Economic appraisal of the potential flood damages associated with no remedial works / maintenance to the existing river and harbour assets.
2.2.2.2 2017 Tidal Flood Strategy - Options Identification and Environmental Appraisal Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. A high-level environmental appraisal of 39 long list strategic options.
2.2.2.3 2017 Tidal Flood Strategy – Preliminary Highway Impact Assessment Supporting evidence for 2017 Study to assess disruption and monetary impact of River Avon flooding to the Bristol highway network.
2.2.3 2017 Tidal Flood Strategy - Short List Options Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Describes the process by which the long list of 39 options were narrowed to a short list of eight strategic options.
2.2.3.1 2017 Tidal Flood Strategy - Hydraulic Modelling Report (Short Listing Phase) Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Details the model build, methodology and baseline results.
2.2.3.2 2017 Tidal Flood Strategy - Defacto Defences, Pill and Shirehampton updates Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Describes improvements to defacto defence and Pill / Shirehampton flood risk. The impact of the updates on the flood modelling extent is presented.
2.2.3.3 2017 Tidal Flood Strategy - Second Avon Crossing Preliminary Investigation Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. High-level feasibility study and transport cost benefit analysis to test the opportunity for a second bridge crossing of the River Avon near M5 to test synergies with barrier (or barrage) flood risk management options.
2.2.3.4 2017 Tidal Flood Strategy – River Avon Tidal Power Preliminary Investigation Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Preliminary high-level desktop study into opportunity for tidal power from the Avon working in conjunction with the potential barrier (or barrage) flood risk management options.
2.2.4 2017 Tidal Flood Strategy - Preferred Option Selection Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Describes the process by which the short list of eight strategic options was appraised to identify a preferred approach.
2.2.4.1 2017 Tidal Flood Strategy - Economic Appraisal (preferred option phase) Briefing Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Presents the methodology and results of the economic assessment.
2.2.4.2 2017 Tidal Flood Strategy - Hydraulic Modelling Report (Option Phase) Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Report explaining the flood risk in the study area, dominated by tidal events. Develops and refines do-something options to support the economic case.
2.2.4.3 2017 Tidal Flood Strategy - Options Identification and Environmental Appraisal Addendum Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Addendum to addresses changes since the Options Identification and Environmental Appraisal Report.
2.2.4.4 2017 Tidal Flood Strategy - Pre-scoping (for EIA) Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. A Pre-Scoping report to provide a framework for the future Environmental Impact Assessment process and precedes a formal request to the determining authority, BCC, for an opinion on whether the project is deemed ‘EIA Development’ or the expected scope of the EIA (a ‘Scoping Report’).
2.2.5 2017 Tidal Flood Strategy - Preferred Option Development Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Documents an additional phase of works to assist with the development of the preferred option to support the Strategy.
2.2.5.1 2017 Tidal Flood Strategy - Outline Design Briefing Report Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Describes the methodology and assumptions used to develop the preferred option budget estimates.
2.2.5.2 2017 Tidal Flood Strategy - Additional Hydraulic Modelling (Preferred Option Development Phase) Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Additional modelling to refine the Preferred Option including fluvial benefits for lower return periods, residual risk from defence overtopping, breach/failure of lock gates and detriment.
2.2.5.3 2017 Tidal Flood Strategy - Economic Appraisal Update Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. A further economic appraisal study including quantifying the benefits associated with the phasing of the chosen option.
2.2.5.4 2017 Tidal Flood Strategy – Financing Baseline Technical Note Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Summarise the findings of additional economic testing and Partnership Funding Assessment.
2.3 2017 Tidal Flood Strategy – Outline Funding Strategy Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Sets out the proposed approaches to identifying potential funding sources and contributions, as well as the type and timing.
2.4 2017 Tidal Flood Strategy – Residual Risk Technical Note Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Residual risk associated with the Preferred Strategic option with respect to the National Planning Policy Framework. 
2.4.1 2017 Tidal Flood Strategy – Defence Breach Modelling Technical Note Supporting evidence for 2017 Study into strategic approach to manage tidal flood risk to Bristol. Additional modelling involves assessing residual risk as a result of a breach in the proposed defences along the River Avon.

 

 

Areas

  • All Areas

Audiences

  • All residents

Interests

  • Environment