Arbroath (Brothock Water) Flood Protection Scheme

Angus Council has awarded the contract for the Arbroath Flood Protection Scheme to Morrison Construction.

Arbroath (Brothock Water) Flood Protection Scheme – funded by Scottish Government and Angus Council – has been designed to reduce the risk of flooding from the Brothock Water, which runs through the coastal town, and provide a one in 200-year standard of protection.

It is a national priority project under the Flood Risk Management Strategy and has been developed in partnership with the Scottish Environment Protection Agency (SEPA).

The project had been due to start in May this year but, in common with almost all areas of the UK-construction sector, has experienced some delay as a result of the Covid-19 pandemic response.

Morrison Construction has been appointed following a tender evaluation process and is currently engaged in a detailed pre-start review of the £12 million project with a view to commencing work shortly. This review will ensure compliance with Covid-19 guidelines and working practices.

Communities Convener, Cllr Mark Salmond said: “I am delighted that we can confirm the award of the contract to Morrison Construction. The coronavirus pandemic has had a huge impact on our lives – at home and at work, and for leisure and industry. No section of our community has been left untouched by this emergency, but it will be good to see these works commencing soon.

“This provides some good news and certainty around the Arbroath Flood Scheme – a project that will undoubtedly have really positive outcomes for a large number of the town’s residents.”

Stephen Slessor, Regional Director for Morrison Construction, said :”Morrison Construction has a strong track record across the Environment sector and we look forward to starting work with the Scottish Government and Angus Council on this important scheme which will deliver long lasting benefits to the community.”

The scheme is focused on holding back flows in the catchment above Arbroath to reduce flows in Brothock Water thus protecting parts of the town that have suffered from flooding in the past and remain at risk from flooding.

It will remove 530 people and their properties from their current level of flood risk, preventing flood damage that averages at £840,000 each year. Once underway, the project will take approximately 18-months to complete.

The scheme builds on a successful partnership between Scottish Government, Angus Council and Morrison Construction which saw the delivery of the Brechin Flood Prevention Scheme, one of the biggest civil engineering projects ever undertaken in Angus at the time, and which provides a 1 in 200 years’ standard of defence against flooding.

Scheme proposals

The Arbroath Flood Protection Scheme has been developed to protect the town from flooding. The scheme is based on the concept of controlling the volume of flood water entering the Brothock during extreme flood conditions.

The key elements of the work are:

  • The construction of three flood storage areas at Brothock Meadows, St Vigeans and Hercules Den, using embankments and flow controls to retain flood water above the natural ground level. Water will only be stored in these flood areas during a flood event, with the purpose of controlling the flow/volume of water entering the Brothock in Arbroath. This will avoid the water breaching the banks.
  • Enhanced defences including a combination of new flood walls where there are no flood defences, or where existing defences are in poor condition, local raising of existing walls and some minor remedial works to existing walls.

Arbroath and the Brothock Water have historically suffered from flooding.

In 1987 a flood prevention scheme was constructed to limit over bank flows from the Brothock. After further flooding a study was carried out to identify the potential risk of flooding in Arbroath and this resulted in the Arbroath Flood Prevention Strategy. This strategy identified actions to reduce flood risk in the town and led to the development of the flood prevention scheme.

The scheme was developed under the Flood Risk Management (Scotland) Act 2009 and is funded by Scottish Government and Angus Council. This national priority project has been developed in partnership with Scottish Environment Protection Agency (SEPA).

The Arbroath Flood Protection Scheme (AFPS) will use a system of Flood Storage Areas (FSA’s) and improvements to the existing flood protection systems along the Brothock Water through Arbroath, to give a level of protection to its citizens and businesses that have been affected by previous floods.

The scheme has been designed to sustain a 1/200 year flood event. The term “1/200 year flood” is a term used to describe the probability of a flood of a certain level happening in a given year. Although unlikely, it is possible that 200 year flood events could happen within a month of each other.

This level of protection will reduce the risk of flooding for 530 people and their properties and protect against flood damage that averages at £840,000 each year.

The Arbroath scheme is ranked nationally as a priority project.

It was identified as an action under the Flood Risk Management Strategy and will be delivered between 2020 and 2022. More information on the strategy is available on the SEPA website (Tay Estuary and Montrose Basin Local Plan District).

Its inclusion in the strategy means it is likely the scheme received capital grant funding from the Scottish Government.

The scheme was promoted under the Flood Risk Management (Scotland) Act 2009. The act allows the council access to private land to construct flood defences.

We have liaised with all affected residents and landowners and will contact them again as necessary for the construction works.

As well as providing flood protection, the scheme has a number of additional environmental benefits:

  • the Brothock Water is known to flood and is included in SEPA’s flood map
  • there is rich vegetation/scrub and rough grassland along the Brothock Water that may provide suitable habitat for a range of species that could include European Protected Species
  • Brothock Water passes through two conservation areas, Arbroath Abbey to Harbour Area and St Vigeans
  • there are a number of residential properties adjacent to the Brothock Water within the study area
  • there are a number of scheduled monuments close to the proposed storage areas, namely St Vigeans symbol stones and Templeton, ring ditch and crop marks
  • there is likely to be impacts on agricultural land
  • there is likely to be a variety of bird species present in the area and the existing habitats may be suitable during the breeding bird season
  • there are a number of listed buildings within the vicinity of the proposed works
  • pedestrians will experience various viewpoints of the river provided by foot and road bridges

The Flood Risk Management (Scotland) Act 2009 (AFPS) introduced a new approach to flood risk management in Scotland.

The act introduces a more sustainable and modern approach to flood risk management, suited to the needs of the 21st century and to the impact of climate change.

It also creates a more joined up and co-ordinated process to manage flood risk at a national and local level.

The local plan will detail the implementation of actions to manage flood risk including flood protection schemes, which are the equivalent to the AFPS.

Responsibility for flood risk management planning falls in the main to the Scottish Environmental Protection Agency, local authorities and Scottish Water.

Residents can reduce the damage and disruption caused by flooding by being prepared.

For more information visit our Flooding Advice page.

Brothock Meadows Flood Storage Area

Operation no Description of operation

Operation 1 Brothock Meadows FSA General Arrangement

Operation 1 Brothock Meadows Plan and Sections

Operation 1 Brothock Meadows Details

Brothock Meadows flood storage area consists of a rock fill embankment with sheet pile cut off. The embankment will be grassed over its entire length. The dam crest will act as a multi stage spill arrangement. The downstream face and the initial apron will consist of grassed hollow concrete block to provide erosion protection. The conduit through the embankment will be a 900mm square reinforced box culvert. Baffles will be included within the culvert to hold natural bed gravels.

St Vigeans Flood Storage Area

Operation no Description of operation

Operation 2 St Vigeans FSA General Arrangement

Operation 2 St Vigeans Plan and Sections

Operation 2 St Vigeans Southern Embankment

St Vigeans flood storage area consists of a rock fill embankment with impermeable core and cut off. The embankment will be grassed over its entire length. The dam crest will act as a multi stage spill arrangement. The downstream face and the initial apron will consist of grassed hollow concrete block to provide erosion protection. The flow control structure consists of a short culvert section, total length 3m. The culvert section will span bank to bank and the culvert height will be approximately the height of the existing river training walls. The channel bed will be reinforced along the length of the flow control arrangement. A debris capture / trash screen will be located some distance upstream of the control structure to capture any large debris that could lead to the blockage of the control structure.Six box culverts 1.5m wide by 0.7m high will be installed through the railway embankment to connect the two parts of the Brothock Water floodplain that is intersected by the railway embankment.

 

Hercules Den Flood Storage Area

Operation no Description of operation

Operation 3 Hercules Den FSA General Arrangement

Operation 3 Hercules Den Embankment and Typical Section

Hercules den flood storage area consists of a grassed earth fill embankment along Park View. A short section of flood wall will provide an entrance to the park and support for a flood gate across the entrance. Ground levels adjacent to Kirkton Road will re-profiled to provide a consistent spill level and grassed. A new screen arrangement will be provided at the culvert inlet within Hercules Den to ease future maintenance.

Drainage for the playing fields will be improved to aid recovery following flood events and flood protection provided to the pavilion. A new debris screen arrangement will be provided at the culvert inlet within Hercules Den to ease future maintenance.

 

Operation no Description of operation
Operation 4 Remedial works to trash screen and erection of post and rail fence across to prevent debris from by-passing screen at upstream end of town.
Operation 5 Sheet piled wall with concrete cope and fence along the top. Maximum defence height of 1.0m. Wall length 20m.
Operation 6 Flood doors on existing gauging station building. Stilling well pipe to be extended above flood level within gauging station building. Short section of existing brick wall to be rendered to provide flood protection and new concrete cope added. Wall length 5.5m.
Operation 7, 8, 9

7. Existing reinforced concrete flood wall is to be raised by 260mm. Wall length 13m.

8. Existing reinforced concrete flood wall is to be raised by 200mm. Wall length 30m.

9. Existing reinforced concrete flood wall is to be raised by 160mm. Wall length 65m.

Operation 10 Existing reinforced concrete bridge parapet upstand to be raised by 330mm.
Operation 11, 12

11. Existing reinforced concrete flood wall next to scrap yard to be raised by 300mm. Wall length 55m.

12. Existing reinforced concrete flood wall next to business centre to be raised by 300mm. Wall length 30m.

Operation 13

Construction of reinforced concrete retaining wall behind existing masonry wall. Typical defence height 400mm. Defence length 13m.

Operation 14 Construct new brick wall to close flow path along access path. Regrade path to prevent ponding of water behind wall. Wall height 800mm and length approximately 2m.
Operation 15 Construct new brick wall to close flow path along access path. Regrade path to prevent ponding of water behind wall. Wall height 900mm and length approximately 2m.
Operation 16

Construction of reinforced concrete retaining wall behind existing masonry wall. Typical defence height 1.6m above protected ground and 900mm above existing defence level. Defence length 48.5m.

Operation 17 Construct block work walls within old openings to reinforce the existing brickwork.
Operation 18

Construction of reinforced concrete retaining wall behind existing masonry wall. Typical defence height 1.6m above protected ground. Defence length 23m.

Operation 19 Existing wall to have brick current brick infill replaced with sandstone blocks of the same dimensions as the existing sandstone elements of the wall. Defence length 30m.
Operation 20 Construction of reinforced concrete retaining wall with sheet pile cut off behind existing masonry wall. Typical defence height 1.6m above protected ground. Defence length 32m.
Operation 21 Existing parapet wall to be rendered to provide additional waterproofing. New cope to be added to the top of the wall. Defence length 11m.
Operation 22

Construct new flood defence wall consisting of brickwork wall with coping stone. Defence height 220mm and wall length 4.5m. Steel angle to be added along edge of concrete platform to provide additional defence. Length of angle along edge of platform 7m.

Operation 23 Construct new flood defence wall and fence.
Operation 24 New brick wall and coping stone. Wall length 3.6m.
Operation 25

Construct new flood defence wall consisting of brickwork wall with coping stone. Defence height 190mm and wall length 3m.

Operation 26

Grassed earth bund with sheet pile cut off. Maximum defence height 750mm. Wall length 42m.

Operation 27 New RC floodwall with sheet pile cut off. New hand railings along wall cope. Maximum defence height 600mm. Wall length 32m.
Operation 28, 29

28. Construct new RC flood wall. Maximum defence height 260mm above current ground level. Tie new wall to existing RC river training wall. Wall length 19m.

29. Construct new RC flood wall. New hand railings along wall cope. Maximum defence height 260mm above current ground level. Tie new wall to existing masonry river training wall. Wall length 18m. Provision of concrete footing to wall to prevent further scour.

Operation 30 Add steel angle to bridge parapet to increase standard of protection. Approximate length 18m.
Operation 31

No defence requirements – provision of step access into watercourse to allow access for future maintenance and new guardrail provided to protect the edge.

Operation 32, 1 of 2 Render existing masonry wall to provide additional waterproofing. Length of Wall 70m. Construct RC outer wall to existing masonry wall over 33m length.
Operation 32, 2 of 2  
Operation 33 New RC flood wall with masonry cladding Maximum height to river bed 2.44m, defence height 540mm. New pedestrian handrail included on top of the proposed wall. Wall length 11m.
Operation 34 Add steel angle to bridge parapet to increase standard of protection. Approximate length 17m.
Operation 35 Construct new brick wall to close flow path along access path. Regrade path to prevent ponding of water behind wall. Wall height 800mm and length approximately 2m.
Operation 36, 37

36. Glass flood barrier to be fixed over windows.

37. Block up boarded up window in cellar of public house.

Operation 38

Construct new RC flood wall. Inclusion of hand rail along the wall copes. Maximum defence height 460mm above current ground level. Tie new wall to existing masonry river training wall. Wall length 29m.

Operation 39 Extend existing wall across access stone steps. Infill behind wall with structural fill up to existing ground level.

Flood events are referred to in terms of their Annual Exceedance Probability (AEP). The AEP is a measure of the likelihood that a flood of a given magnitude will occur once or more within any given year. The AEP is expressed as either a “one in X” value (e.g. 1:200) or as a percentage (e.g. 1:200 equates to 0.5%).

The table below summarises the return periods discussed in this report, and the equivalent AEP of these events.

Return Period Annual Exceedance
Probability (AEP)
1 in 2 year (Q2) 50%
1 in 5 year (Q5) 20%
1 in 20 year (Q20) 5%
1 in 100 year (Q100) 1%
1 in 200 year (Q200) 0.5%
1 in 500 year (Q500) 0.2%
1 in 1000 year (Q1000) 0.1%

Brothock Meadows

Hercules Den

St Vigeans

Throughout the construction stages of the project we will endeavour to engage with the public to ensure we share the process of construction.

The contractor already has local involvement with the Arbroath Community in the form of sponsorship of the “Young Lichties” of Arbroath FC.

Working together, the contractor and Angus Council will coordinate information releases via social media and this website where we will keep you up to date with where we will be working and any disruptions that may be necessary.

We shall organise school visits to local primary and secondary school (dependant on Covid19 restrictions) to keep pupils informed of what we are doing and the dangers of construction sites.

The contractor shall help support and develop local employment through their new start employment opportunities and also support local suppliers.

These documents meet the requirements of the flood risk legislation and associated regulations.

As importantly, these documents seek to provide information on the proposed scheme to all those with an interest. They seek to answer questions that people may have as well as describing how to make an objection to the proposed scheme.

Further information on the scheme is available on our Arbroath (Brothock Water) pages or please contact us at arbroathflood@angus.gov.uk.

Index

  1. Scheme Notice

including details of:

  • powers conferred upon Angus Council by the Flood Risk Management (Scotland) Act 2009
  • location and times for inspection of scheme documents
  • how to make an objection
  • process to confirm or reject the proposed scheme.

Scheme Documents

including details of:

Objection Form

Requesting the information we need to treat your objection as valid.

4. Summary of supporting documents:

Arbroath Flood Strategy, Flood Risk and Management Options Report (March 2012)

See Appendix A of Development of Fluvial Flood Risk Strategy document which includes details of:

  • Options Appraisal
  • Economic Analysis

Consultation Report (July 2017) which includes details of:

  • Scheme origin
  • Arbroath Flood Strategy
  • Local Flood Risk Management Plan
  • Community engagement

Environmental Statement (August 2017) including details of:

Environmental Impact Assessment and Mitigation Measures:

Economic Assessment Report (September 2017) which includes details of:

  • Benefits-Cost Assessment

Development of Fluvial Flood Risk Strategy (May 2018) which includes details of:

  • Overview of Flood Risk in Arbroath
  • Objectives for managing local flood risk
  • Appendix A - 2012 Arbroath Flood Strategy, Flood Risk and Management Options Report

If further assistance is required for any aspect of the scheme documents, please email arbroathflood@angus.gov.uk.

For information on flooding alerts visit our flood warnings page.