What is St Austell Resilient Bay Regeneration (StARR) project?


    The StARR project aims to manage flood risk in the area. It consists of different measures to help store and manage the flow of water through the Par River catchments to make it an even better place to work and live. For an overview of the whole programme and progress updates please see the StARR project web page at: www.cornwall.gov.uk/starrproject



    Do you have evidence that we need this project?

    Yes, flooding has occurred within the area since records began in the early 1900s.  A comprehensive study has been carried out to investigate the impact of flooding based on more frequent storms and the impact of climate change.


    A community survey undertaken by the St Blaise Neighbourhood Plan identified flooding as a key issue within the area.  A public engagement event was  held in April 2018. Feedback from the event demonstrated support for the project, with 88% of attendees stating they would support investment to reduce the majority of flood events, knowing there will be short term disruption during the construction phase.



    Where does the main flooding happen?

    The table below shows the flooding events and locations:

    DateLocationsCause
    2017Station Road, Par Lane, St. Blazey Road, St Andrews Road, Par Station
    Rainfall
    Dec 2012

    River flooding affected 23 properties in Station Road, Snowlands and Par Sands Caravan park.

    A390 and retail park also affected.
    2 watercourses breached their banks. It was the wettest year on record in England
    Nov 2010

    River and surface water flooding affected 55 properties in St. Blazey, the petrol station, roads and 124 properties at Par Moor

    Eden Project flooded
    Extreme rainfall, run off from hills and roads, high river flows, blocked streams and culverts.
    June 2009River flooding affected 3 properties on Station Road and Rebecca Close.
    River channel blocked with undergrowth
    Sept 1990Surface water flooding affected 2 properties in Doubletrees
    Defective highway drainage
    Jan 1982
    Surface water flooding affected 9 properties in Station Road
    High water table and poor drainage
    Sept 1976Surface water flooding affected 10 properties in Fore Street, Middleway and Brooks Corner
    Blocked drainage system
    Feb 1974River and tidal flooding affected roads, the railway and 70 properties in par lane and Station Road
    Tide locking of Par River and feeder streams.
    1852River flooding caused the bridge and several properties to collapse and flooded other properties in St Blazey
    Very heavy rain and river overtopped.


    What is the source of the flooding?

    Par and St Blazey are prone to 3 types of flooding:

    Surface Water flooding – when rainwater doesn’t drain away through the drainage systems or soak into the ground and lies on or flows over the ground.

    River Flooding – “fluvial” flooding occurs when excessively heavy or prolonged rainfall causes a river or stream to exceed its capacity and overtop its banks.

    Tide-locking – flooding occurs when a high tide causes water to back-flow up the Par River, St Blazey Stream and Polmear Stream, particularly when flow levels in those watercourses are high due to intense or prolonged rainfall in the catchment.

    How big is the problem in the area?





    Why are Par and St Blazey so prone to flooding?

    Many of the homes, businesses and infrastructure of the towns sit in the bed of a former estuary. The natural river has also been raised up and split in two to drain through the town in the form of the River Par and Treffry Canal which adds to the flood risk.  Mining waste has built up and raised the level of the ground.

    a) Historic causes:

    This map from 1539-40 shows how the original river estuary extended up to Luxulyan.  The river was already silting up by the 16th century due to historic tin mining and this was exacerbated by large scale mining and china clay quarrying in the 19th century. Par was built on the silted up river bed and St Blazey on sea sand.  Station Road lies on the old river bed and the site of Par Green was once a saltwater fish pond. Another legacy of mining and china clay quarrying is that many of the watercourses in the area were altered by diversion and mine drainage.

    b) Local flood causes within Par and St Blazey:




    c) Catchment-wide flood causes

    The Par River catchment collects water across a large area (see blue line on map below) from Roche and Bugle in the west and as far north east to the A30 near Bodmin.  Activity across the whole catchment affects the flow and quality of water in local streams and rivers. For instance, vertical ploughing of hilly fields can cause flooding and water quality problems further downstream.


    d) The perched watercourse: section showing flood risk from perched watercourses





    Which areas are at risk?

    Find the flood risk for your area on this Government map

    You can use the drop-down arrow at the top left of the mapping page to see the risk from rivers and the sea, surface water and reservoirs.

    Does a "one in 20" year flood event only happen once in 20 years?

    A “one in 20” year event has a statistical chance of happening once in 20 years on average, or rather a 5% probability of happening in any given year. Theoretically, this could happen next year or in 20 years’ time. It could happen more often or less often, but has a 5% or 1 in 20 likelihood of happening in any one year. These statistics are based on past measurements and do not take into account a moving baseline due to climate change.

    Is the risk of flooding increasing


    Flooding has been happening in this community for a long time. Flood defences installed since the 1970s have reduced the risk, but only for 1 in 5 and 1 in 20 year flood events. Parts of the existing system are ageing, close to capacity and at risk of failure. 


    Climate change is increasing the likelihood of more extreme rainfall events, coastal storms and sea level rise. Our coastline is also changing due to natural erosion. Over the next 100 years Par Beach is projected to retreat inland by 100m. “Managed Realignment” will be needed at Par Docks by 2025 to adapt to sea level rise and by 2055 at Par Sands to adapt to coastal erosion. See the Cornwall and Isles of Scilly Shoreline Management Plan.


    Is climate change making the flooding worse?

    Yes.  Cornwall Council declared a climate emergency in January 2019. Climate change is causing more intense storms, rising sea levels and extreme flooding. Cornwall is particularly susceptible to flood risk and coastal erosion. You can read more on Cornwall Council's climate change website.

    My property has never flooded, why is this scheme needed?


    Many of the homes, businesses and infrastructure of the towns sit in the bed of a former estuary. The natural river has also been raised up and split in two to drain through the town in the form of the River Par and Treffry Canal which adds to the flood risk.


    There is an existing flood defence scheme in place in the town which is working to keep your home from being flooded – this includes flood banks, walls, sluice gates and reservoirs. However, that scheme is now getting old and in need of maintenance. In addition, the risk of flooding has increased in some places, so the existing scheme needs to be updated. This is happening as part of the StARR Project.


    Some assets are in poor condition, for example a section of the stone wall that contains the Par River slumped at Ponts Mill in the summer of 2019 and was repaired by Cornwall Council and the Environment Agency.  Another section of wall that contains the Par River and supports the railway line collapsed in early November 2019 causing significant disruption; emergency repair work was carried out by Network Rail.

    Historically this area has flooded, with the last major event taking place in 2010.

     

    There will also be a significant review and upgrade of the highways and surface water management system (ie drains) as part of the Cornwall Council side of the project.



    Will this prevent future flooding of my home/business?

    The StARR project aims to reduce flood risk in the short term but the risk of flooding can never be fully removed.



    What is being done to prevent new developments from increasing flood risk?


    The Flood and Water Management Act 2010 requires Sustainable Drainage Systems. Developers must demonstrate a drainage strategy for their developments that does not increase the current rate of field runoff, up to and including a 1 in 100 year event.


    In addition, the area west of St Blazey is a “critical drainage area” (CDA), meaning any new developments upstream of the CDA must be designed to avoid any harmful downstream impacts and, preferably, to reduce the risk.


    Under Section 106 of the Water Industry Act 1991, all home owners can have foul and surface water from their property connected to the public sewerage system. Before South West Water will grant permission to discharge to the combined sewer they review the hydraulic capacity of the combined sewerage network and require building control approval. 

    How will StARR reduce the risk of flooding?

    Flood risk can be managed (but never fully prevented) by slowing down and controlling the flow of water through the catchment. Due to the complexity of the area the StARR project will use a number of different methods to help achieve this. These include:


    a)     Use of green spaces to temporarily store water during extreme rainfall.


    b)     Slowing water down by routing it through vegetation (contour tree planting, rain gardens).


    c)      Reinstating low spots to enable water to follow its natural course.


    d)    Removing barriers between the river and its natural floodplain.

    e)  Changing existing flood infrastructure.

    f)   Keeping watercourses, drainage features and the combined sewer network free from blockages.


    How many properties will be better protected in Par and St. Blazey?

    The StARR project aims to reduce flood risk to over 450 homes and businesses in Par and St. Blazey. The project will also repair existing defences which help to protect many more.


    Will this be a benefit to me?

    The community of Par & St Blazey will have improved flood protection contributing to the potential for economic growth.  Furthermore, key transport infrastructure will be better protected as a result of the works such as the A390 and rail network. 

    Why doesn’t the Environment Agency do more dredging?

    Dredging is an important part of our river maintenance programme. We consider each location carefully and do it where we know it will make a difference. Understanding where dredging will and won’t reduce flood risk is key. 


    Dredging is unlikely to be effective in isolation, but it can be part of a solution involving multiple interventions.  The document below gives more information about the practice of dredging:

    Floods and dredging report





    How do you know what is being proposed will work?

    We use consultants to help us produce the evidence needed.

    They use:

    1)     ground measurements and measure the river flow

    2)     reports and photographs from previous flood events

    3)     computers to predict where the water will go


    Is this a long-term solution?

    No, this project only aims to provide a short to medium term solution of about 25 years.

    Cornwall Council will commission a consultant to produce a long-term plan for the area in consultation with representatives of the community, such as those who have developed the Neighbourhood Plans.

    Will the project make a difference to our home insurance?

    This answer is being reviewed.

    Will the project make a difference to our house price?

    We cannot guarantee that house prices will be affected.


    Who is involved and who is leading the project?

    The partners are Cornwall Council, the Environment Agency, South West Water, Westcountry Rivers Trust and the University of Exeter

    Cornwall Council and the Environment Agency are leading the project.  Cornwall Council is responsible for developing the surface water elements (on the highway) as well as the upper catchment elements and the Environment Agency is responsible for the main river elements of the project.


    What about South West Water?


    South West Water are one of our delivery partners within the project and are making a contribution towards the overall cost.  


    How does this fit with regeneration proposals for the area?

    We are working with local Neighbourhood Plan groups to look at the long-term plans for the area. 


    Who is responsible for managing flood risk?

    Who

    What they are responsible for

    Cornwall Council

    Ordinary watercourses (e.g. Prideaux Stream), surface water from roads, pavements and groundwater.

    Environment Agency

    Main rivers (e.g. Par River, St Blazey Stream), reservoirs and the sea.

    South West Water

    Public sewers

    Landowners

    Have legal duties to keep watercourses on or next to private land clear.

    Property owners

    Private drainage systems

    Everyone

    Within flood risk areas and in the upper catchment is responsible for reducing runoff on their land or property and for keeping drains and sewers free from blockage.


    What is natural flood management?

    To be added

    How much will the project cost?

    The overall budget allocated from the project in £32m.Some funds are allocated for future maintenance.


    How is the project being funded?

    Funding has come from a number of sources. £7.8 Million of funding from the England European Regional Development Fund (ERDF), £10.8m from the UK Government Department for the Environment, Food and Rural Affairs (DEFRA) Growth Funds, £12m of Flood Defence Grant in Aid, the University of Exeter, South West Water and a £2m match funding contribution from Cornwall Council.

    How have you decided what has been included in these proposals?


    Over the last few years there have been extensive hydraulic modelling, surveying and ground investigations taking place within the area which are helping to inform the final design. 


    What will the schemes look like?


    Generally, all schemes will improve the storage, drainage and management of water through the catchment area.  This is achieved by refurbishing existing assets on the main river, creating new attenuation features, re-naturalising floodplains, re-profiling the highway to divert surface water and planting trees to improve drainage.


    Landscape Architects will be involved to ensure the measures will enhance the landscape, taking account of the natural and historic value of the area.


    The project has been going on for the last 5 years; why is this taking so long?

    Projects of this scale and complexity using multiple funders take a significant amount of time to develop and deliver.  There are a number of different delivery partners involved and each must have an input in order to progress the project.  Funding had to be secured to deliver the works meaning the project had to stop and start as funding was released.


    When will the work start and when will it end?

    Work is planned to begin this summer, 2020.

    The project is due for completion in 2023.

    What will happen next?

    For Cornwall Council’s work, design consultants Cormac Solutions Ltd (CSL) and their partners, Aecom, have submitted 2 of the 3 urban infrastructure planning applications and are developing the detailed design for each of the schemes.  Some of the project measures are more complex than others, therefore it is likely that the local infrastructure works will be developed and started on site first, with the more complex major schemes being developed later.  The Environment Agency have submitted their planning application for the main river work and are now preparing the contract documents. 

    Construction work to strengthen the river bank at Ponts Mill will start in August 2020.

    I have additional information on a past flood event/ecology/cultural heritage; how can I share this with you?

    The majority of local information has already been gathered from community groups and previous consultation events and we believe that we are addressing the known issues that fall within the scope of this phase of works.  However, if you wish to send us any further photographs or information to keep as part of the historical records, please send information by email to starr@cornwall.gov.uk


    starr@cornwall.gov.uk


    How can I share my views about the proposals?

    Members of the public and/or community representatives contributed to:


    • a pre-funding public engagement event (held in April 2018)
    • a post-funding public engagement event (held in June 2019)
    • a pre-planning consultation event (held in November 2019) – a community working group helped to shape what the infrastructure schemes could look like at each site.

    You will also be able to share your views:

    Can I object to the proposals?


    Yes, the majority of the proposals will need full planning permission and will therefore be presented formally as part of the planning application.


    Is this not just a waste of money?

    We know that the community is at flood risk and therefore it is the duty of Cornwall Council and the Environment Agency to investigate how to manage flood risk. All works are procured under EU law to ensure best value for money. Not taking action will result in increasing costs to taxpayers for repairing flood damage to public infrastructure.


    How can I have my say in the Environment Agency’s proposals for the river?

Kilhallon

    1. What are the sources of flooding around Kilhallon?

    There are three primary sources of flooding in the Kilhallon area:

    • Groundwater comes up through the ground due to soil conditions being mainly granular and as such permeable
    • Surface water from the steep-sided valley with limited flood routes to the river, and
    • River (fluvial) flooding from the Treffry Canal when levels rise to a point to overtop the bank.

    2. Why are you raising the flood defences along the Treffry Canal when there have never been any instances of flood water overtopping the existing canal bank and we don’t suffer flooding from it?

    While there may not have been any flooding from the Treffry Canal in the past, making best use of capacity across the watercourses in the Par and St Blazey area is one of the ways the project is helping increase flood resilience. The wider proposals will enhance the existing flow regime maximising the rivers’ capacity in times of flood. Where economically viable we are promoting raising defences with an outcome of better protecting 72 more residential properties in the town. Wider proposals to increase flood resilience by improving or raising other sections of flood defence sometimes require localised improvements elsewhere. This helps reduce flood risk for the community at large and ensure potential for flooding isn’t displaced from one area to another. The effects of climate change add further pressure to the ability to deal with flooding in the future.

    Unfortunately, hydraulic modelling of the wider proposals over winter 2019/20, showed an increase in flood risk from the Treffry Canal to the properties at Kilhallon. As this is increase is legally unacceptable, we have been reviewing the options to mitigate increased flood risk in Kilhallon.

    We approached and met the residents of Kilhallon to raise this issue and present early indicative solutions following the modelling results. Since then we have refined our designs as shown on the attached drawings. Specifically, we plan to raise the Treffry Canal defence height on the fence line between Environment Agency owned land and private landowners’ gardens at Kilhallon.

    The main focus on this developing design is to limit the use of piling works along the length. The reason for us reviewing the design in this way has been following our consultation with the residents and listening to their concerns. The change from the sheet piled solution has two main advantages:

    • reducing the number of trees needing removing to provide works access, as we will have more flexibility to work around as many existing trees as possible (the original sheet piling works would need a wide, straight access track next to the pile line, whereas an access track to build a wall with concrete foundation is a lot more flexible to work around obstructions)
    • removing sheet piling removes the underground sheet pile wall, that may affect groundwater flow paths.

    3. Is the Treffry Canal depth limited by the A390 road bridge deck clearance?

    The culvert under the A390 St Austell Road (Bridge Street) effectively acts as a control structure but is not the only parameter dictating river depths. 

    4. Will the proposed sheet piling, designed to reduce the risk of flooding from the Treffry Canal, worsen ground and surface water flooding by preventing it draining from the east? If not, why?

    As mentioned in the answer to question 2, ongoing design development has removed the majority of the originally proposed sheet piling works to mitigate this risk. The current proposals use a combination of measures, including: sections of sheet piling, precast concrete wall, masonry wall, bespoke Flex MSE products and flood gates to reduce the risk of future canal bank overtopping. The existing open channels, drains, clack valves and pump that help remove groundwater and surface water flow from the east will remain.

    5. What is the maintenance regime for the existing pump?

    The pump is routinely maintained and serviced by the Environment Agency to keep it fully operational. It is also linked to the Environment Agency’s Flood Incident telemetry system to raise the alarm if not working, independent of water levels.

    6. Can we have a bigger pump?

    Replacing the existing pump is not a cost-effective solution to the relatively low risk posed by groundwater and surface water flooding. The project’s funding is targeted where the main areas of flood risk and benefit can be realised. In general, flood resilience measures are moving away from underground, piped and pumped solutions due to the relatively high maintenance costs and ongoing burden. Lots of StARR’s measures are therefore focussed on surface-level measures and techniques requiring little maintenance, with ‘buried solutions’ and mechanical equipment only used as a last resort.

    7. Why can’t you just maintain the existing highway drainage and prevent flooding?

    We can never realistically prevent flooding, just reduce its frequency and extent and impact.

    All roads which Cornwall Council are the highway authority for are maintained in accordance with the Highway Maintenance Manual (HMM). The section of road and gullies which we’re aware residents kindly volunteer to try and keep clear from debris in Kilhallon is the U6142205. This is designated as a Class 5a Minor Access Road. Details of the formal maintenance regime and more information can be found at: https://www.cornwall.gov.uk/transport-and-streets/roads-highwaysand-pavements/highway-maintenance/ 

    Anyone can report a highways drainage issue of flooding on the highway at: https://www.cornwall.gov.uk/transport-and-streets/roads-highways-and-pavements/highwaymaintenance/drainage-and-flooding-on-the-highway/ 

    Risk management authorities already work in partnership with community flood groups to help manage and reduce flood risk, including from blocked gullies, culverts and trash screens (typically metal grids covering pipes, culverts and watercourses). Although not part of StARR’s scope we would like to work more with the flood group and wider community to identify local areas of concern and develop plans for enhancing flood resilience, particularly in extreme events.


    8. Why are you chopping down trees?

    The new scope of works further reduces the amount of tree felling required, compared to the original sheet piled solution. Any tree removal still required will only be necessary for construction and future maintenance access.

    9. What are the next steps?

    We are currently confirming costs for the increased scope of works and seeking funding, without which we cannot proceed. Assuming we secure funding, the design process will start in the new year (2021). We will be developing this design throughout spring / summer 2021 and will engage the community at appropriate points during its development. The proposed construction would start in winter 2021/22.

White House Farm area

    1. Basis of flood prevention/flood resilience scheme should be to protect existing flood plains and residents not to put them at greater risk

    The primary aim of this project is to reduce flood risk. The ethos is to not worsen flood risk to properties and we cannot legally do this. The safeguard for this is the Planning Process.

    Reconnecting watercourses to natural flood plains is a recognised technique in working with natural processes and natural flood management to reduce flood risk. It is this principle which we are aiming to develop in the flood plain fields near White House Farm. Whilst this may increase the amount of wet ground typically found in the fields compared to existing, the overall flood risk will be less.

    Through further developing an earlier concept design, we aim to demonstrate that residents will not be put at greater risk from flooding through our proposals. However, we are still in the early stages of Developed Design and need to work our way through the remaining key stages:

    • ongoing Developed Design
    • Submit Planning Application
    • Technical (Detailed) Design
    • Planning Application determined
    • Construction start

    2. Why remove 13 million gallons of existing flood water storage on land north of Aberdeen Close & Rebecca Close?

    We propose to look at a range of culvert inlet levels to optimise the point at which water from the River Par enters the flood plain, whilst balancing this with the implications of triggering the Reservoirs Act. Essentially, the principle is that water will remain in the Par River until it rises sufficiently to the invert level allowing water to flow into the flood plain field, utilising this additional storage. Water levels will then drop in the field as the Par River lowers and water drains out.

    3. Details of forthcoming planning application have not been consulted on with local councils or displayed as part of public consultation process prior to submission

    The planning applications for individual measures in the StARR project are being submitted at different times. The planning application for the White House Farm measures was due to be submitted on 3 July 2020, therefore providing sufficient time to further engage with landowners, the public and statutory consultees at the appropriate time. In the meantime, we may need to request access to land for surveys etc. to help us develop and refine these proposals. We are grateful for cooperation in helping us to do this.

    4. Natural flood attenuation to north of A390 should be available when overtopping of Par River occurs

    See Questions 1 and 2. Reconnecting the Par River to the flood plain will help achieve natural flood attenuation.

    5. Removal of existing flood bank would permanently flood the floodplain which would then not be available for flood storage, resulting in flood water overtopping the Par River downstream (précised).

    See Questions 1 and 2. Various iterations of the proposals are being investigated to demonstrate the impact before designs are progressed to the Technical (Detailed) Design stage. The works at White House Farm are part of a package of interventions being carried out and must be viewed as part of the whole. The Environment Agency is also carrying out defence improvements along the Par River. As noted above, it would be an offence to put any additional properties at risk downstream and the aim of this scheme is to reduce flood risk.

    6…it is an offence to remove flood storage because if you do it moves water along and results in flooding elsewhere… scheme contradicts EA/CC flood protection policies.

    The range of measures across the StARR Project complement each other with some:

    • slowing the flow of water higher up the catchment
    • storing water temporarily, before
    • slowly releasing it further downstream.

    The White House Farm proposals primarily act as a temporary storage facility.

    7. CC has a role to ensure that any scheme fulfils the original objectives which is a flood prevention scheme. Wetland removes flood storage and CC led scheme should not include the loss of any flood storage or removal of existing flood protection.

    See Question 6. Reconnecting watercourses to natural flood plains is a recognised technique in working with natural processes to reduce flood risk. It is this principle which we are aiming to develop in the flood plain fields near White House Farm. Whilst this may increase the amount of wet ground typically found in the fields compared to existing, the overall flood risk will be less.

    The increased amount of typically wet ground and generally fluctuating water levels, may have a positive overall effect on wildlife but this is a potentially secondary benefit of the measure.

    8. Existing network of waterways have been neglected leading to flooding problems.

    We acknowledge the ongoing need to maintain existing watercourses, the costs involved in continuing to do this and challenging financial circumstances for maintaining authorities. Part of the StARR Project’s ethos is to develop sustainable ways of managing flood water, avoiding subterranean infrastructure, promoting self-cleaning channels and reducing the need for maintenance wherever possible. Please contact Cornwall Council if you have concerns over any existing watercourses.

    9. Where are the original StARR concepts: manage rising sea levels, improve bathing water quality, create large storage ponds, alignment & roll back of dunes, optimise existing flood storage areas, use existing infrastructure (eg quarries) to store water

    The StARR Project aims to deliver a number of overarching aspirations, some of which form specific outputs that need to be met for the £34m funding we have successfully applied for.

    Whilst substantial, this is significantly less than the project’s original c.£80m budget to deliver the type of aspirations and concepts as set out in the early supporting ‘bidding’ documentation (e.g. the infographic and visualisation). We have therefore had to scale back the proposals to meet the funding available and that we’ve been able to secure. All this needs to continually satisfy our partners’ business cases, funding conditions, outputs and deliver reduced flood risk to the community. The current measures are a balance of those meeting the principles of slow, store and release referred to in Question 6.

    We will update the supporting documentation as the project progresses to better reflect the measures being developed and funded. Monitoring and evaluation will be undertaken to ensure the outputs are achieved. Whilst some specific proposals have been scaled back, many of the principles referred to are being delivered by measures such as:

    Managing the impact of rising sea levels caused by climate change:

    • a Masterplan is being commissioned to set out the needs and aspirations in the wider area beyond the life and flood resilience nature of the project
    • Asset improvement along the main river being progressed by the EA
    • Par Beach Management Plan helping to restore healthy dune system (taken forward by Cornwall Council outside the scope of the StARR Project)


    Improve bathing water quality:

    • reducing silt from watercourses
    • improved infiltration and remediation through natural flood management measures such as tree planting
    • improved land management practices through the work undertaken by Westcountry Rivers Trust


    Create large storage features on open land:

    • measures proposed north and south of Aberdeen Close 
    • Burrows Centre
    • Trenovissick Road
    • Edgcumbe Terrace


    Optimising flood storage areas:

    • Lower Molinnis near Bugle
    • White House Farm