CABINET – 1 July 2014 EXECUTIVE SUMMARY OF AGENDA ITEM 8 Report title: River Avon Strategic Flood Defence Wards affected: City Centre wards - Southville, Bedminster, Windmill Hill, Brislington West, Lawrence Hill, Easton, Cabot, Ashley, Clifton Strategic Director: Barra Mac Ruairi, Place Report Author: Alistair Cox, Service Manager Strategic Transport RECOMMENDATION for the Mayor’s approval: 1. Subject to funding being available The Strategic Director – Place be given delegated authority to progress the next phase of design and assessment work for the River Avon Strategic Flood Defence in a budget envelope of up to £600,000 for all costs associated with the five different work packages. . Key background / detail: a. The main threat from flooding to the centre of Bristol is from a tidal event along the River Avon. This threat would be further exacerbated when the impact of climate change is taken into consideration, this full impact occurring by 2100; b. Further design work is required to determine which of two options would be the appropriate solution; i) A rising barrier in the River Avon downstream of the Clifton Suspension Bridge; ii) Walls along the River Avon from the entrance to the Floating Harbour along the River Avon (New Cut) between Underfall Yard and Netham lock. These walls could be up to 2m in height, for short lengths (at low points), but would be significantly lower where ground levels are higher. There would be no requirement to construct walls around the Floating Harbour. c. There are significant concerns with the option of walls along the River Avon, in the manner described above, as this may be successful in flood defence but in terms of the success of the city, specifically it may be inappropriate in terms of access to the river for local communities, wider public and visitors to Bristol as well as being negative in terms of economic, environmental and heritage considerations. It could also restrict future development opportunities through the severance it creates. A barrier is not considered to have the same impact on Bristol. d. Key details: i) In the short term the existing threat of flooding is to; Cumberland Road/Avon Crescent; Bathurst Basin; St Phillip’s Marsh. The first two locations are being addressed by works being provided as part of the Metro Bus route from Ashton Vale to Temple Meads. Further analysis is being carried out to assess in detail the impact to St Phillip’s Marsh. ii) In the medium term (5 -20 years) maintenance and upgrade of existing Harbour Assets is required to maintain a standard of flood protection. This will be focussed on developing an Asset management plan for Harbour
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CABINET – 1 July 2014 EXECUTIVE SUMMARY OF AGENDA ITEM 8 Report title: River Avon Strategic Flood Defence Wards affected: City Centre wards - Southville, Bedminster, Windmill Hill, Brislington West, Lawrence Hill, Easton, Cabot, Ashley, Clifton Strategic Director: Barra Mac Ruairi, Place Report Author: Alistair Cox, Service Manager Strategic Transport RECOMMENDATION for the Mayor’s approval: 1. Subject to funding being available The Strategic Director – Place be given
delegated authority to progress the next phase of design and assessment work for the River Avon Strategic Flood Defence in a budget envelope of up to £600,000 for all costs associated with the five different work packages. .
Key background / detail: a. The main threat from flooding to the centre of Bristol is from a tidal event along the
River Avon. This threat would be further exacerbated when the impact of climate change is taken into consideration, this full impact occurring by 2100;
b. Further design work is required to determine which of two options would be the appropriate solution;
i) A rising barrier in the River Avon downstream of the Clifton Suspension Bridge;
ii) Walls along the River Avon from the entrance to the Floating Harbour along the River Avon (New Cut) between Underfall Yard and Netham lock. These walls could be up to 2m in height, for short lengths (at low points), but would be significantly lower where ground levels are higher. There would be no requirement to construct walls around the Floating Harbour.
c. There are significant concerns with the option of walls along the River Avon, in the manner described above, as this may be successful in flood defence but in terms of the success of the city, specifically it may be inappropriate in terms of access to the river for local communities, wider public and visitors to Bristol as well as being negative in terms of economic, environmental and heritage considerations. It could also restrict future development opportunities through the severance it creates. A barrier is not considered to have the same impact on Bristol.
d. Key details:
i) In the short term the existing threat of flooding is to;
Cumberland Road/Avon Crescent;
Bathurst Basin;
St Phillip’s Marsh. The first two locations are being addressed by works being provided as part of the Metro Bus route from Ashton Vale to Temple Meads. Further analysis is being carried out to assess in detail the impact to St Phillip’s Marsh.
ii) In the medium term (5 -20 years) maintenance and upgrade of existing Harbour Assets is required to maintain a standard of flood protection. This will be focussed on developing an Asset management plan for Harbour
Assets to move from reactive a basis of investment to a more informed data led process
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AGENDA ITEM 8
BRISTOL CITY COUNCIL CABINET
1 July 2014
REPORT TITLE: River Avon Strategic Flood Defence Ward(s) affected by this report: City Centre wards - Southville, Bedminster, Windmill Hill,
Brislington West, Lawrence Hill, Easton, Cabot, Ashley, Clifton Strategic Director: Barra Mac Ruairi, Place Report author: Alistair Cox, Service Manager Strategic Transport Contact telephone no. 0117 922 2357 & e-mail address: [email protected] Purpose of the report: The purpose of the report is to inform the Mayor of the current and future risks from flood events along the River Avon and to seek approval to commence development of mitigation measures.
RECOMMENDATION for the Mayor’s approval:
1. Subject to funding being available, the Strategic Director, Place be given delegated authority to progress the next phase of design and technical assessment work for the River Avon Strategic Flood Defence in a budget envelope of up to £600,000 for all costs associated with the five different work packages.
The proposal:
2. The Flood and Water Management Act 2010 places a statutory duty on Bristol City Council to act as Lead Local Flood Authority (LLFA). In discharging this duty Bristol City Council has lead responsibility for managing the risk of flooding from surface water, groundwater and watercourses. A number of studies have been undertaken since 2010 to assess the threat of flooding to Bristol, ie. the likelihood and the impact of flooding from these sources.
3. The conclusion of the main study, the Central Area Flood Risk Assessment (CAFRA), was that the main threat from flooding to the centre of Bristol was from a tidal event along the River Avon. This threat would be further exacerbated when the impact of climate change is taken into consideration, this full impact being predicted to occur by the year 2110. An example of the impact of a tidal surge along the River Avon occurred on the 3rd January 2014 resulting in the deployment of the City‟s flood barrier on Avon Crescent in Cabot Ward (See Appendix 1 for photograph of deployed
barrier). The event on the 3rd January, and subsequent events in both February and March, caused some disruption to services. It should be noted that the magnitude of these events is significantly less than the events we need to be planning and preparing for. With the threat of climate change and sea level rise, the events of the 3rd January 2014 could start to occur many times every year. Appendix 2 and 3 provide details of predicted significant flood events, both in the current day and into the future, taking into account the impact of climate change.
4. The threat of flooding in the short term (0-5years) is at three points;
a. Cumberland Road/Avon Crescent – This is being addressed by works being provided as part of the MetroBus route from Ashton Vale to Temple Meads.
b. Bathurst Basin/Commercial Rd - This is also being addressed by works being provided as part of the MetroBus route from Ashton Vale to Temple Meads.
c. St Phillips Marsh – Further analysis is being carried out to identify in more detail exactly which properties, both residential and business, are likely to be affected by current flood threat.
5. In the medium term (5 - 20 years) maintenance and upgrade of existing harbour assets is required to maintain a standard of flood protection. This will be focused on developing an asset management plan for harbour assets to move from a reactive basis of investment to a more informed data-led process. This work is under way.
6. In the longer term (20+ years) a strategic flood defence for the River Avon is required to mitigate climate change impacts. In autumn 2013 officers commenced a high level strategic options feasibility study to understand more clearly what might be the appropriate form of strategic flood defence to mitigate the risk of a tidally dominant flooding event occurring along the River Avon. The conclusion of this piece of work is that there are two potential solutions namely:
A rising barrier in the River Avon downstream of the Clifton Suspension Bridge;
Walls along the River Avon from the entrance to the Floating Harbour along the River Avon (New Cut) between Underfall Yard and Netham lock. These walls could be up to 2m in height, for short lengths (at low points), but would be significantly lower where ground levels are higher. There would be no requirement to construct walls around the Floating Harbour.
There are significant concerns with the option of walls along the River Avon, in the manner described above as, whilst this may be successful in flood defence, it could have a highly detrimental effect on the success of the city. Specifically this option may be unsuitable in maintaining access to the river for local communities, wider public and visitors to Bristol as well as being negative in terms of economic, environmental and heritage considerations. It could also restrict future development opportunities through the severance it creates. A barrier is not considered to have the same impact on Bristol
At this time there are no firm proposals as to what a rising barrier or walls might look like or where they might be located. In order to move this project to the next stage we need to carry out detailed investigatory and development work over the next 18 months. This work will identify which option is the most appropriate mitigation and will lead to further detailed design work. The further investigatory and development work required is as follows;
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Hydraulic model refinement;
Economic assessment, hydraulic option modelling and outline design;
Environmental Impact Assessment;
Habitat Regulations Assessment scoping, assessment and consultation;
Ground and geotechnical investigations. It is not intended to let these work packages as one single contract as the conclusions of one work stream will inform the next. Each work package will need to be reviewed and scrutinised with partners and stakeholders e.g. Environment Agency, Natural England, Wessex Water as well as others. The work will therefore be phased and packaged as a series of separate smaller contracts. Whilst the main emphasis of the expenditure in the next phase of works will be on developing the options for the rising tidal barrier, additional work is required on the option of walls to ensure it is fully considered as part of any future Cabinet decision.
It is estimated this will cost up to £600k. Approximately £469k has already been identified for the first phase of this work, meaning that if the recommendation is agreed the first phase can be completed in any event and subsequent work could be commissioned without the need for a further report to the Mayor and Cabinet, but only if the necessary funding were forthcoming.
7. The estimated cost of economic loss resulting from flood damage, caused by a 1 in
200 annual chance flood event (the event scenario used to assess planning applications) occurring in the central area of Bristol is of the order of £160 million (at today‟s prices). This cost covers damage to properties, businesses, including disruption to travel networks, impact on emergency services or other civil amenities e.g. hospitals. This cost is estimated to increase to approximately £800 million (at today‟s prices) when the impact of climate change is taken into account if no action is taken over the next 100 years. Both of the above figures do not include any provision for the impact on inward business investment if a strategic flood defence is not progressed and in the worst case a significant event happens. This cost is impossible to quantify but will be significantly higher than both the above figures by several orders. It is estimated that approximately 1,000 properties are currently at risk of flooding from the above event scenario (1 in 200 annual chance) with this rising to approximately 4,000 properties when climate change is taken into account.
8. Development opportunities in the central area of Bristol, within the Environment Agency Flood Zone (See Appendix 4), are restricted due to the current predicted threat of flooding. The Environment Agency, who are a statutory consultee on all planning applications in a Flood Zone, currently object to any planning applications for development comprising residential proposals at ground floor level within the Flood Zone area (inclusive of climate change) covering central Bristol. The precise cost of this restriction on development is impossible to predict accurately. However the estimated cumulative added-value, over the next 25 years, to Bristol‟s economy from proposed development within the areas currently at risk of flooding in central Bristol is estimated to exceed £9 billion at today‟s prices.
9. The Sustainable Development and Scrutiny Commission at their meeting on the 19th
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February 2014 noted the two options that are being progressed with respect to mitigating flood risk resulting from tidal surge along the River Avon.
Consultation and scrutiny input: a. Internal consultation:
Mayor Briefing Jan 2013; Assistant Mayoral Briefing July 2013; Assistant Mayor Briefing 9th December 2014; Sustainable Development and Transport Committee, annual Flood update report, most recent 14th February 2014; Assistant Mayor Briefing 3rd February 2014
b. External consultation: Consultation has taken place regarding the options work undertaken to date with Risk Management Authorities, as defined by the Flood and Water Management Act. To date this has been with the Environment Agency and Wessex Water as well as Natural England. Other options considered: As part of the Avon Strategic Flood Defences Feasibility Study, our consultants undertook a high-level options scoping assessment, to consider all potential options for flood mitigation. The consultants were tasked to „scope out‟ the unfeasible options that would not meet the main study objective, which was to mitigate the tidal flood risk from the River Avon, inclusive of climate change. Examples of options that were scoped out are as follows:
Using the Floating Harbour to store tidal flood water - Discounted as this is not likely to be feasible to mitigate the climate change flood scenario due to the volumes of water that would enter the Harbour;
Increasing River Avon channel capacity through dredging and channel widening - Discounted as this doesn‟t mitigate tidal flooding and would be unfeasible given the impact on the public realm;
Upstream storage on the River Avon to attenuate river flows - Discounted as this would not mitigate tidal flooding. However, this could be considered in the future as part of the overall strategy to mitigate flooding in Bristol depending on the outcomes of future design work.
A number of options were also recommended that do not meet the study objectives (mitigate tidal flooding) in full themselves but should be incorporated as part of wider flood risk management initiatives that will still help to reduce flood risk to the city centre, which have in turn been included within the City Council‟s draft Local Flood Risk Management Strategy. Such options include;
Improve flood forecasting, warning and planning to maximise the amount and accuracy of flood warnings issued to enable resilient communities;
Encourage catchment management initiatives such as sustainable drainage, green infrastructure and vegetation planting to help mitigate water flows through the catchment and reduce reliance on hard infrastructure.
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Risk management / assessment:
FIGURE 1 The risks associated with the implementation of the (subject) decision :
No. RISK
Threat to achievement of the key objectives of the report
INHERENT RISK
(Before controls)
RISK CONTROL MEASURES
Mitigation (ie controls) and Evaluation (ie effectiveness of mitigation).
CURRENT RISK
(After controls)
RISK OWNER
Impact Probability
Impact Probability
1. Place Directorate will not have sufficient resources to progress with the design work
Med Low Work will be led by officers with appropriate support and resources provided through existing Framework contracts
Low Low Strategic Director, Place
2. Funding streams identified are unable to deliver
Med Med Work streams can be reduced to comply with the available level of funding
Low Low Strategic Director, Place
3. Creates an expectation with stakeholders and wider public that a Strategic Flood Defence is going to be delivered soon
Med Med Consultation with stakeholders and wider public through design work will manage this expectation
Low Med Strategic Director, Place
FIGURE 2 The risks associated with not implementing the (subject) decision:
No. RISK
Threat to achievement of the key objectives of the report
INHERENT RISK
(Before controls)
RISK CONTROL MEASURES
Mitigation (ie controls) and Evaluation (ie effectiveness of mitigation).
CURRENT RISK
(After controls)
RISK OWNER
Impact Probability Impact Probability
1 The future risk of flooding to the central area of Bristol when impact of climate change is included will not be addressed
High High In the short and medium term, up to 20 years, mitigation measures are being provided but nothing would be planned for longer term when impact climate change is taken into account
Med High Strategic Director, Place
2 Both the current and future (when climate change impacts) economic prosperity of central Bristol (including part of the Enterprise Zone) would continue to be limited because of the risk of flooding. This also restricts the type of development that can occur i.e. limiting residential opportunities.
High Med None planned as only a commitment to delivery of a Strategic Flood Defence for the River Avon would mitigate this risk.
High Med Strategic Director, Place
3 The reputation of Bristol being open for inward business investment as well our reputation with other Risk Management Authorities e.g. Environment Agency may be undermined if no long term strategy is seen to be being developed
High Med None planned as only a commitment to delivery of a Strategic Flood Defence for the River Avon would mitigate this risk
High Med Strategic Director, Place
Public sector equality duties: Before making a decision, section 149 of the Equality Act 2010 requires that each decision-maker considers the need to promote equality for persons with the following “protected characteristics”: age, disability, gender reassignment, pregnancy and maternity, race, religion or belief, sex, sexual orientation. Each
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decision-maker must, therefore, have due regard to the need to: i) eliminate discrimination, harassment, victimisation and any other conduct prohibited under the Equality Act 2010. ii) advance equality of opportunity between persons who share a relevant protected characteristic and those do not share it. This involves having due regard, in particular, to the need to: - remove or minimise disadvantage suffered by persons who share a relevant protected characteristic. - take steps to meet the needs of persons who share a relevant protected characteristic that are different from the needs of people who do not share it (in relation to disabled people, this includes, in particular, steps to take account of disabled persons' disabilities); - encourage persons who share a protected characteristic to participate in public life or in any other activity in which participation by such persons is disproportionately low. iii) foster good relations between persons who share a relevant protected characteristic and those who do not share it. This involves having due regard, in particular, to the need to tackle prejudice and promote understanding. The central area of Bristol along the River Avon is at risk of significant flooding along the River Avon and so this could have an impact on residents of Bristol and so needs to be resolved from a health and safety point of view. It is identified that during significant flooding events there is disruption with access to public services which can have a disproportionate effect on certain equalities groups. However, it is important to realise and understand the importance of inclusion and stakeholder engagement. As a result, we can fully understand the difficulties and concerns of individuals from equalities communities as service users and also from service providers. As it has not been possible to complete a full Equalities Impact Assessment as the scheme is significantly undefined in terms of physical form or location it will mean that as the scheme develops that a review will need to be undertaken and a full Equalities Impact Assessment will need to be considered and completed. Advice given by Jane Hamill, Equalities Advisor Date 1st May 2014 Eco impact assessment This proposed design work will generate very minor impacts such as physical works including borehole and ground work investigations, and associated travel. These impacts are unlikely to be significant and no mitigation is proposed. Any future works arising from the studies would be likely to generate very significant environmental impacts. These would be subject to a future Cabinet report, Bristol Core Strategy Planning Policies and – depending on the scale of the works – a statutory Environmental Impact Assessment. There are no significant environmental impacts arising from this proposal.
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Advice given by Steve Ransom, Environmental Performance Programme Co-ordinator Date 30th April 2014 Resource and legal implications: Finance a. Financial (revenue) implications: Confirmed that the following reserves;
DEFRA Grant analysis code BE068 £298,673;
Highway Fees analysis code BE064 £170,645; can be used for the work detailed in this cabinet report. Advice given by Mike Allen, Strategic Finance Partner Date 30th April 2014 b. Financial (capital) implications: Currently there are no capital implications for this project as the work required is to carry out further design work only in order to be able to identify what the appropriate Strategic Flood Defence would be and where it might be located. A further report to Cabinet will be required following this work. However at this time we estimate the order of likely costs associated with the delivery of a Strategic Flood Defence for the River Avon could be in excess of £100 million. Advice given by Mike Allen, Strategic Finance Partner Date 30th April 2014 Comments from the Corporate Capital Programme Board: Please see comment above under Finance item b. Advice given by Mike Allen, Strategic Finance Partner Date 30th April 2014 a. Legal implications: The Council is a Lead Local Flood Authority and as such the Mayor (and/or those he arranges to act in this behalf) is a Flood Risk Management Authority for the area. This brings the duty (i.e. “must do”) to develop, maintain, apply and monitor a strategy for local flood risk management in its area. The recommendation in this report seeks authority from the Mayor to enable steps to be taken towards achieving these statutory obligations as regards the River Avon. There are specific scrutiny responsibilities (i.e. support to the decision making process by way of review and recommendation) in relation to the management of flood risk and in Bristol these responsibilities are undertaken by the Sustainable Development and Transport
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Scrutiny Commission. If the recommendation is agreed the services may only be procured in accordance with the Council‟s Financial Procedure Rules in part 4 of its constitution, including in compliance with the procurement regulations Advice given by Pauline Powell, Team Leader-PT &R for Service Director-Legal
Services Date 30th April 2014 d. Land / property implications: The Council owns a large number of properties which would be affected by a tidal surge. For operational property there would be disruption to service delivery. For investment property there would be a loss of value particularly whilst development opportunities are restricted as per para 7. Adoption of a Strategic Flood Defence would provide clarity and restore confidence in property decision making. Advice given by Ian Smith, Project Leader Date 3rd February 2014 e. Human resources implications:
There are a number of strands to this work, such as, geotechnical and ground investigations, further flow modelling, Environmental Impact Assessment. In order to effectively deliver this work, the Council is likely to use a number of consultants, who would be engaged through an existing Consultancy Framework. There are no redundancy or redeployment implications.
Advice given by Mark Williams, Service Manager People Strategy Date 6th February 2014 Appendices: Appendix 1 – Photo of Flood Defence Barrier deployed at Avon Crescent 3rd January 2014; Appendix 2 – Plan showing current predicted extent of flooding from tidal surge along River Avon in 2014; Appendix 3 – Plan showing future predicted extent of flooding from tidal surge along River Avon when impact of climate change is taken into account; Appendix 4 – Plan showing current Environment Agency Flood Zone designations for central Bristol. Access to information (background papers): Central Area Flood Risk Assessment Summary report – http://www.bristol.gov.uk/page/planning-and-building-regulations/strategic-flood-risk-assessment-sfra Consultant‟s Report River Avon Strategic Flood Defence – http://www.bristol.gov.uk/page/planning-and-building-regulations/strategic-flood-risk-assessment-sfra
