Site Allocations DPD Strategic Flood Risk Report

Cornwall Local Plan: Site Allocations DPD

Strategic Flood Risk Report

Appendix 6

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Contents

Appendix 6 – Exception Tests: Harbourside Car Park and Wherrytown, Penzance ...... 3 SFRA2: Harbourside Car Park (Mixed Use) (PZ-M1) ...... 6 SFRA2: Wherrytown (Mixed Use) (PZ-M3) ...... 14

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Appendix 6 – Exception Tests: Harbourside Car Park and Wherrytown, Penzance

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1. Introduction This appendix sets out the Exception Test to two sites as part of the Site Allocations DPD Strategic Flood Risk Assessment:  Harbourside Car Park, Penzance;  Wherrytown, Penzance. In addition, Appendix 7 sets out the Par Docks Sequential and Exception Test document.

The Exception Test provides a method of managing flood risk while still allowing development to occur to meet wider sustainability objectives. The test is only applied for areas with substantial flood zone 2, 3a and 3b, where the sequential test was unable to identify appropriate alternative sites.

The exception test for each site has been conducted at a strategic level for the Site Allocations document and is split into two parts as follows:

 Part (a) wider sustainability benefits  Part (b) safe development

The site profiles SFRA2 information, sequential test and Exception Test information should be made available to developers for masterplanning, applications and site specific flood risk assessments (FRA’s) to help ensure that they are able to satisfy the requirements for the Exception Test at the detailed design stages.

2. Sites Two of the sitesARCHIVED requiring the Exception Test are located in Penzance and one is located in Par. The Exception Test is set out for the two Penzance sites here; the Exception Test for Par Docks is set out in Appendix 7.

2.1 Harbourside Car Park, Penzance Part A: Wider Sustainability Benefits The 2 ha harbour side car park is located within the town centre area. It is proposed as a mixed use siteEVIDENCE for retail, leisure and employment with some residential on upper storeys.

At the time of applying the exception test The Mounts Bay Shoreline Management study presents emerging options for strategic sea and flood defence solutions along Penzance waterfront which would apply to the Harbour Car Park. It is therefore assumed that the preferred solution will be incorporated and or influence any proposal. DOCUMENT

The Sustainability Appraisal concluded the following:  The site has good links to the strategic transport network, and is adjacent to the main line railway station and bus station in comparison to other sites around the urban area.

 Development of this mixed use allocation is to include retail and employment provision, so would improve access to and provision of additional services and facilities and therefore provide employment opportunities

The established Vision and Objectives for Penzance which is set out within the strategy for the town include the following:  To re-establish the status of Penzance’s Town Centre - strengthen, improve and extend the quality of the offer.  To develop cohesive harbour and waterfront strategies for Penzance and Newlyn that enhance the harbour offer  To become West Cornwall’s premiere tourist destination

 Provide services and economic opportunities to support a wide hinterland  Offer a range of equitable housing opportunities  Support a thriving economy, based primarily on the marine, creative, leisure, retail and tourism industries;  Address the predicted changes in sea conditions due to climate change.

Penzance Town Centre like many faces a challenge in retaining its role as a vibrant retail, commercial centre for the community and town. Modern retailers struggle to find larger footprint stores within Cornwall’s historic town centres and often look at easier to develop out of town retail options which further threaten the health and vitality of centres. The location of the harbour car park, sitting within the town centre, on the waterfront therefore provides a unique regeneration opportunity for Penzance to provide space for retail and commercial uses, restaurants and cafes in an attractive waterside location with the potential to increase footfall and expenditure to the existing centre, by providing a focal point and destination for residents and visitors to the town. It is considered that due to a lack of suitable and available alternative locations, if the harbour car park was unable to be redeveloped for these regeneration uses then the risk would be further decline through reduced footfall and expenditure within the town from both residents and visitors.

This context is recognised and supported by Penzance Town Council who are preparing a Neighbourhood Plan which focuses on improving the town centre and waterfront regeneration opportunities including a particular emphasis around regenerating the harbour side car park.

There is also an aspiration to deliver a waterfront cycle route from Marazion to Newlyn, the delivery of whichARCHIVED can also support the delivery of improved flood resilience measures for the conurbation. In addition, the aspiration is to ensure this route has various ‘nodes’ which act as points from which people can access / depart the cycle network. The Harbour Car park is recognised as one of the most important sites as it will deliver part of the cycle route, plus act as the most important node, as it is adjacent to the transport interchange and the node can help attract people using the route into the town centre.

Summary EVIDENCE The Harbourside car park is considered to be a key waterside regeneration opportunity site within the town, within the existing town centre area. It is considered that attractive waterfront uses will provide significant social and economic benefits to the town in line with the vision, objectives of the long term strategy for the Town, as identified in the Sustainability Appraisal. DOCUMENT Conclusions The above demonstrates that the wider sustainability benefits of developing the site significantly outweigh flood risk and the first part of the Exception test is passed.

Part B Safe Development The second part of the Exception Test requires that development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere and where possible reducing flood risk elsewhere. The Council considers that the information set out in the Harbour car park SFRA2 site profile demonstrates both strategic and specific considerations and solutions in relation to the site, including the emerging conclusions of the ‘Mounts Bay Shoreline Management Strategy’, to enable the site allocation to meet the requirements of part b of the exception test.

overall. The Council in consultation with the Environment Agency will assess any submissions against the above criteria.

SFRA2: Harbourside Car Park (Mixed Use) (PZ-M1)

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Flood ZoneEVIDENCE 2 The site is within Flood Zone 2 Flood Zone 3a The site is within Flood Zone 3a Flood Zone 3b Not within site Critical Drainage Areas Whole site falls within the Penzance Critical Drainage Area Shoreline Management Final flood outline @ 2055 with flood zone 3 affects Plan designation most of the site. DOCUMENTProjected coastline erosion @ 2055 (with prevention) seems not to affect the site. Projected coastline erosion @ 2055 (without prevention) does affect the northern part of the site and southern boundary.

Epoch 1: Hold the Line Epoch 2: southern part of site: Hold the Line; northern part of site: Managed Realignment Epoch 3: southern part of site: Hold the Line; northern part of site: Managed Realignment Surface water flooding The site is entirely within a Critical Drainage Area. map Part of the northern portion of the site is likely to experience surface water flooding Hazard Maps Show significant risk across the site in relation to tidal flooding from wave overtopping, due to a combination of extreme high tides and extreme 6

weather events during a 1 in 200 years event, if the site remains undefended. During such events waves would overtop the harbour wall and move around the flat site area at a velocity and depth that would be an extreme hazard on around 60% of the site with a significant hazard on the remaining area, with water then receding back to the sea. Factoring in climate change the hazard map indicates that there would be extreme hazard on around 95% of the site. Hydrology assessment This site is currently a seafront car park for of site’s surface water Penzance. Any development of the site would have issues to provide future-proofed sea defences and flood storage.

How to address flood risk issues as integral part of developing the site

Issues to be addressed

Site specific – Tidal flooding, surface water flooding, flood storage and coastal erosion. The shoreline management plan sets out that this flood risk 3 site will suffer from coastal erosion at its northern part and southern boundary of the site (without prevention) by 2055. It also recognises that hold the line at the southern boundary is appropriate due to its use. ARCHIVED The Hazard maps for the sites show that the specific hazard is from wave overtopping with subsequent water moving around and then receding back to the sea. The southern and eastern half of the site, undefended, shows an extreme hazard which would be dangerous for all in a 1 in 200 year event; this increases to cover almost all of the site area factoring in the climate change scenario.EVIDENCE Due to the nature of the hazard however there would be several hours warning in place before such significant events occurring.

This hazard will need to be taken into account as integral to any detailed development of the site.

PresentDOCUMENT ground level is around 3.5-3.8 m.OD. 1 in 200 tidal level (Flood Zone 3) is presently 3.5 m.OD, potentially rising to 4.5 m.OD through 100 year planning horizon.

Solutions and Policy recommendations

The existing harbour wall currently offers some protection to storm surges and waves. Any development of the site would have to provide enhanced future- proofed harbour wall sea defences around the southern and eastern seaward perimeters of the site at an appropriate height. For example such a defence could include an inner and outer wall to enable overtopping waves to then drain 7

away to the sea; however this will be a key consideration at any detailed design stage of development proposals.

There needs to be an element of flexibility in considerations due to need to incorporate the emerging long term solutions and recommendations in the ‘Mounts Bay Shoreline Management Strategy’ which will be relevant to this site. Any site proposals will need to consider, incorporate and contribute to the preferred strategic sea flood defence solution.

Under consideration at the time of writing is an ‘outer harbour breakwater’ which if feasible and deliverable as a project would create an adequate sea defence for the site and wider area over the medium and long term.

Any finished levels above 4.5 m.OD should be outside tidal flood zone. However, there is still a residual risk of wave overtopping and therefore a need to provide additional raised defences on seaward sides of development

Raising of ground levels would not increase flood risk elsewhere as the nature of the risk is wave overtopping with water then receding back to the sea and not elsewhere.

Floor levels will be established in any detailed design scheme but must be above surrounding ground level to enable water move around without entering buildings e.g. as a guide around 0.3 metres. ARCHIVED Flood resilient internal finishes should be considered i.e. services/wiring above set heights and internal safe refuge provided.

Ground level low impact areas of the site such as public realm and footpaths should be designed to be ‘floodable’ during extreme flood events.

ResidualEVIDENCE uses should only be on upper floors of any development.

Safe access and egress routes during a tidal flooding event will need to be provided along the western boundary of the site on to Wharf Road, Albert Street and Station Road – Albert St and Station Rd in particular are both outside of the (undefended) hazard area and are of a height to ensure they would not flood. TheDOCUMENT junction onto wharf road shows a low hazard and this location should be considered for the safe access route from the site in flood events, such a route may need to be raised on entering the site. Specific design of the safe access and egress will need to be undertaken at the detailed development design stage. Careful planning of the development, any overland flow pathways and flood management measures will be required.

A flood warning and evacuation plan must be developed and Cornwall Councils Emergency Planning Team must be consulted during any detailed design proposal.

Due to the nature of the hazard which is a combination of extreme high tides and extreme weather events there will be several hours flood warning before significant events to enable necessary measures to be implemented as part of a site flood warning and evacuation plan.

There is a multi-agency emergency plan for Penzance which will be updated to 8

reflect any new development of this site.

The site drains to tidal waters so water quality will need to be of the highest standard for amenity and biodiversity interests. Site management must ensure no negative impacts on water quality during construction and use.

Surface water drainage will need to be designed in accordance with the SUDS principles and standards set out in the Drainage Guidance for Cornwall to ensure surface water run-off from development is managed appropriately, so that flood risk is not increased.

Sequential Test The majority of the site is Flood Zone 3a.

Proposals for mixed use on this site do not comply with the Sequential Test, which would see the majority of the site as being suitable for only water compatible uses1 and/or essential infrastructure, or more vulnerable uses subject to an Exception Test.

It would not be possible for the proposed development to be built outside of flood zone 3a. Consideration of alternative sites in line with the sequential test has been undertaken as set out ARCHIVEDbelow.

Consideration of Alternative sites have been considered and it has alternative sites not been possible for suitable alternative sites to be identified in line with wider sustainability planning objectives. Appendix 4 sets out a map of EVIDENCEall sites considered and a table listing the reasons why sites were discounted

Exception Test The Exception Test has been applied and the Council considers that the wider sustainability planning objectives outweigh the flood risks in relation to the site. This information can be viewed DOCUMENTin Appendix 3. It is considered that the above information also satisfies part 2 of the exception test. A site specific flood risk assessment will be required by applicants to meet requirements of the Exception Test which will be assessed by the Council in consultation with Environment Agency.

1 Where such uses are designed and constructed to ensure that the Flood Zone remains operational and safe for users in times of flood; there is no loss of floodplain storage; and, water flow is not impeded or flood risk increased elsewhere. 9

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2.2 Wherry Town, Penzance Part A: Wider Sustainability Benefits The 0.5 ha Wherry Town site is proposed as a mixed use site for retail, leisure or employment with some residential on upper storeys. It is currently contains a small supermarket and car park but is soon to be vacant, It is a prominent and visible waterside location on Penzance’s promenade.

At the time of applying the exception test The Mounts Bay Shoreline Management study presents emerging options for strategic sea and flood defence solutions along Penzance waterfront which would apply to the Wherry Town site. It is therefore assumed that the preferred solution will be incorporated and or influence any proposal.

The Sustainability Appraisal concluded the following:  The proposed allocation is for mixed uses and development of the site would improve access to and provision of additional services and facilities as well as employment opportunities.

 Proposed development would deliver a good quality façade on to Western Promenade Road and it is recognised as a key opportunity to create a hub / stopping point which would have a positive effect on tourism

The established Vision and Objectives for Penzance which is set out within the strategy for the town include the following:  To utilise the setting of Mount’s Bay and promote and develop the leisure, business and natural ARCHIVEDassets available within Mount’s Bay to increase its attractiveness  To develop cohesive harbour and waterfront strategies for Penzance and Newlyn that enhance the harbour offer  To become West Cornwall’s premiere tourist destination  Provide services and economic opportunities to support a wide hinterland  Offer a range of equitable housing opportunities  Support a thriving economy, based primarily on the marine, creative, leisure, retail and tourismEVIDENCE industries;  Address the predicted changes in sea conditions due to climate change.

The soon to be vacant Wherry Town plot is located on the promenade between Penzance and Newlyn. The promenade is a key waterfront leisure route for residents and visitors, including families, pedestrians and cyclists, providing views of the wider Penzance bay area to St Michaels MountDOCUMENT and beyond. Terrace development lines the promenade route behind and fronting the main road; development is a mix of residential, hotels, commercial, public houses and cafes. The current vacant wherry town plot is soon to be vacant providing an unsightly gap in the built fabric along the promenade route. Its redevelopment for commercial uses would enable an attractive redevelopment improving the character of the local area and acting as part of the wider regeneration of the promenade route linking Marazion to the east with Newlyn in the west.

It is considered that due to the site is soon to be vacant there is an ongoing risk in this area along the promenade in that it would continue to appear in a condition of decline discouraging further investment, to the detriment of the local economic and social conditions in the Wherrytown area linking Penzance and Newlyn.

This context is recognised by Penzance Town Council who is preparing a Neighbourhood Plan which focuses on improving the town centre and waterfront regeneration opportunities including Wherrytown.

Summary The Wherry Town site is considered to be a key waterside regeneration opportunity site within the town. It is considered that attractive waterfront uses will provide significant social and economic benefits to the town in line with the vision, objectives of the long term strategy for the Town, as identified in the Sustainability Appraisal. Furthermore it is considered that if left vacant and undeveloped it will be a gap in the existing built fabric in a prominent and visible waterside location on Penzance’s promenade, which is a key thoroughfare through the town.

Conclusions The above demonstrates that the wider sustainability benefits of developing the site significantly outweigh flood risk and the first part of the Exception test is passed.

Part B Safe Development The second part of the Exception Test requires that development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere and where possible reducing flood risk elsewhere. The Council considers that the information set out in the Wherrytown SFRA2 site profile demonstrates both strategic and specific considerations and solutions in relation to the site, including the emerging conclusions of the ‘Mounts Bay Shoreline Management Strategy’, to enable the site allocation to meet the requirements of part b of the exception test.

However a site specific flood risk assessment will be required by applicants demonstrating that safe access routes to and from the site avoiding higher risk areas, and that development will be safe withoutARCHIVED increasing flood risk elsewhere and, where possible, will reduce flood risk overall. The Council in consultation with the Environment Agency will assess any submissions against the above criteria.

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SFRA2: Wherrytown (Mixed Use) (PZ-M3)

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Flood Zone 2 The site is within Flood Zone 2 Flood Zone 3a The site is within Flood Zone 3a Flood ZoneEVIDENCE 3b Not within site Critical Drainage Areas Whole site falls within the Penzance Critical Drainage Area Shoreline Management Final flood outline @ 2055 with flood zone 3 Plan designation affects most of the site. Projected coastline erosion @ 2055 (with prevention) seems not to affect the site. DOCUMENTProjected coastline erosion @ 2055 (without prevention) does affect the southern part of the site.

Surface water flooding Part of the southern portion of the site is likely to map experience surface water flooding Hazard Maps Show significant risk across the site in relation to tidal flooding from wave overtopping, due to a combination of extreme high tides and extreme weather events during a 1 in 200 years event, if the site remains undefended. During such events waves would overtop the harbour wall and move over the promenade area opposite and main road before entering the site area and moving around, at a velocity and depth that would be an extreme hazard on around 20% of the southern site area and adjoining the sites western boundary over the 14

stream, with a significant hazard on the remaining area bar a raised area at the middle of the site where there is a low/no hazard, with water then receding back to the sea. Factoring in climate change the hazard map indicates that there would be extreme hazard on around 80% of the site. Hydrology assessment of This site is entirely within Flood Zones 2 and 3a. site’s surface water issues How to address flood risk issues as integral part of developing the site

Issues to be addressed

Site specific – Tidal flooding, surface water flooding, flood storage and coastal erosion. SMP2 states that the northern part of the site will not be defended from the 2nd epoch onwards.

The Hazard maps for the sites show that the specific hazard is from wave overtopping with subsequent water moving over the main road into the site then receding back to the sea. A southern part of the site, undefended, shows an extreme hazard which would be dangerous for all in a 1 in 200 year event; this increases to cover around 80% of the site area factoring in the climate change scenario. Due to the nature of the hazard however there would be several hours warning in place before such significant events occurring. This hazard will need to be takenARCHIVED into account as integral to any detailed development of the site. The stream to the sea sits next to the western boundary of the site at a lower level.

1 in 200 tidal level (Flood Zone 3) is presently 3.5 m.OD, potentially rising to 4.5 m.OD through 100 year planning horizon, and between 5.2 to 5.3 mAOD for a 1 in 200 year plus climate change event. SolutionsEVIDENCE and Policy recommendations

The SMP2 is currently undergoing review, it currently states that the northern part of the site will not be defended from the 2nd epoch onwards, however there is a wider shoreline management strategy which sets out solutions and recommendations – to the north of the site the rail line and station will be defended. DOCUMENT Any development of the site would have to incorporate some form of future- proofed sea defences at the southern seaward perimeter of the site at an appropriate height; this will be a key consideration at any detailed design stage of development proposals.

Any finished levels above 4.5 m.OD should be outside tidal flood zone. 15

However, there is still a residual risk of wave overtopping and therefore a need to provide additional raised defences on seaward sides of development

Raising of ground levels would not increase flood risk elsewhere as the nature of the risk is wave overtopping with water then receding back to the sea and not elsewhere.

Floor levels will be established in any detailed design scheme but must be above surrounding ground level to enable water move around without entering buildings e.g. as a guide around 0.3 metres.

Flood resilient internal finishes should be considered i.e. services/wiring above set heights and internal safe refuge provided.

Ground level low impact areas of the site such as public realm and footpaths should be designed to be ‘floodable’ during extreme flood events.

Residual uses should only be on upper floors of any development.

Safe access and egress during a flooding event can be provided towards the northern eastern corner of the site, careful planning of the development, any overland flow pathways and flood management measures will be required. Specific design of the safe access and egress will be undertaken at the detailed development design stage. ARCHIVED A flood warning and evacuation plan must be developed and Cornwall Councils Emergency Planning Team must be consulted during any detailed design proposal.

There is a multi-agency emergency plan for Penzance which will be updated to reflect any new development of this site. EVIDENCE Due to the nature of the hazard which is a combination of extreme high tides and extreme weather events there will be several hours flood warning before significant events to enable necessary measures to be implemented as part of a site flood warning and evacuation plan.

TheDOCUMENT site drains to tidal waters so water quality will need to be of the highest standard for amenity and biodiversity interests. Site management must ensure no negative impacts on water quality during construction and use.

Sequential Test The majority of the site is Flood Zone 3a.

Proposals for mixed use on this site do not comply with the

Sequential Test, which would see the majority of the site as being suitable for only water compatible uses2 and/or essential infrastructure, or more vulnerable uses subject to an Exception Test. It would not be possible for the proposed development to be built outside of flood zone 3a. Consideration of alternative sites in line with the sequential test has been undertaken as set out below. Consideration Alternative sites have been considered and it has not been of alternative possible for suitable alternative sites to be identified in line sites with wider sustainability planning objectives. Appendix 4 sets out a map of all sites considered and a table listing reasons why sites were discounted Exception Test The Exception Test has been applied and the Council considers that the wider sustainability planning objectives outweigh the flood risks in relation to the site. It is considered that the above information also satisfies part 2 of the exception test. A site specific flood risk assessment will be required by applicants to meet requirements of the Exception Test which will be assessed by the Council in consultation with Environment Agency. The Exception Test for the site can be viewed in Appendix 3.

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2 Where such uses are designed and constructed to ensure that the Flood Zone remains operational and safe for users in times of flood; there is no loss of floodplain storage; and, water flow is not impeded or flood risk increased elsewhere. 17

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2.3 Par Docks The Exception Test document can be viewed in Appendix 7 The ExceptionEVIDENCE Test has been satisfied

3 Conclusion The Council considers that all three sites pass both parts of the Exception Test.

Site specificDOCUMENT FRA will be required by applicants. The Council in consultation with the Environment Agency will assess any submissions.