Perth Surface Water Management Plan
Perth and Kinross Council · 27 May 2026
Back to Climate Change and Sustainability Committee — 27 May 2026 and its agenda
Text extracted from the council's PDF. Layout and reading order may differ from the original.
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Our vision is a Perth and Kinross where everyone can live life well, free from poverty and inequality ___________________________________________________________________ Committee or Board: Climate Change & Sustainability Date of Meeting: 27 May 2026 Report Title: Perth Surface Water Management Plan Report Number: 26/146 Report Author: Gavin Bissett, Engineer, Flooding Team Organisational Lead: Fraser Crofts, Strategic Lead – Environment and Infrastructure ___________________________________________________________________ 1. Purpose 1.1 The purpose of this Report is to summarise the findings and outcomes of the Council’s ‘Perth Surface Water Management Plan (SWMP)'. The report highlights that no viable surface water flood protection schemes have been identified but makes recommendations on other measures that should be taken forward where opportunities for collaboration with other projects exist. 1.2 Sections 1. Purpose 2. Recommendations 3. Background/Context 4. Main Issues 5. Proposals 6. Conclusion 7. Impact Value Assessment 8. Appendices 2. Recommendations It is recommended that the Committee: 2.1 Notes the completion of the Perth SWMP as required by the Tay Flood Risk Management Plan and Local Flood Risk Management Plan.
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2.2 Approves the recommendations of the Perth Surface Water Management Plan, which state that whilst no viable surface water flood protection schemes have been identified, some measures have been found that should be taken forward where opportunities for collaboration with other projects exist. This also includes emphasising, and where possible, supporting the uptake of property flood resilience measures. 2.3 Notes that public engagement has been undertaken to disseminate the findings of the SWMP. 2.4 Notes the requirement to monitor, review and update the Perth SWMP in Cycle 3 (2028-2034). 3. Background/Context 3.1 Under the Flood Risk Management (Scotland) Act 2009, SEPA and lead local authorities published their Cycle 1 Flood Risk Management (FRM) Strategies and Local FRM Plans in December 2015 and June 2016 respectively. These documents set out a range of actions that SEPA and responsible authorities took to manage and, where possible, reduce the risk of flooding over a six- year period. 3.2 The (then) Environment Committee approved the content and publication of the Cycle 1 Tay Local FRM Plan on 1 June 2016 (Report 16/241 refers). The (then) Environment and Infrastructure Committee subsequently approved the content of an Interim Report on the progress made in implementing the Cycle 1 Local FRM Plans on 23 January 2019 (Report 19/16 refers). 3.3 SEPA and lead local authorities published updated Cycle 2 FRM Plans and Local FRM Plans in December 2021 and December 2022 respectively for the six-year period from 2022 to 2028. The Climate Change & Sustainability Committee approved the content and publication of the Cycle 1 Final Report and Cycle 2 Tay Local FRM Plan on 19 December 2022 (Report 22/307 refers). The Climate Change & Sustainability Committee subsequently approved the content of an Interim Report on the progress made in implementing the Cycle 2 Local FRM Plans on 10 November 2025 (Report 25/300 refers). The published documents can be viewed at the following link: http://www.pkc.gov.uk/frmplans 3.4 The published FRM Plans and Local FRM Plans identify various flood studies as a means of further improving the understanding of flood risk in certain locations. The plans identified a Surface Water Management Plan (SWMP) for Perth. The purpose of this study was to build on the significant level of previous investigations regarding surface water flood risk in Perth, and to explore what further action would be required to manage surface water flood risk in Perth and set this out in a plan. Actions could then be identified and assessed against technical, economic and acceptability factors to determine feasibility. Any feasible actions could then be implemented as part of a flood protection scheme.
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3.5 The 2009 Act provides local authorities with discretionary powers to promote flood protection schemes. Only those flood schemes which have been included in the published FRM Plans, the Local FRM Plans and the national priority list are taken forward in the subsequent 6-year period. 3.6 Although public authorities are expected to take a proactive role in managing and, where achievable, lowering flood risk, the primary responsibility for avoiding or managing flood risk still remains with land and property owners. The 2009 Act does not alter this. Individuals, businesses and communities must, therefore, play a critical role in making themselves more resilient and helping to reduce the impact of flooding. 4. Main Issues 4.1 Perth is located in the River Tay catchment within Potentially Vulnerable Area (PVA) 02/08/12. 4.2 The primary sources of potential flooding in Perth are from fluvial (river) and pluvial (surface water) flooding. Fluvial flooding was mitigated through the construction of the Perth Flood Prevention Scheme (PFPS) in 2001 to primarily protect areas of Perth from the River Tay, Perth Town Lade and River Almond. The PFPS was considered, at that time, to have a 1 in 250- year standard of protection. The PFPS also includes flood protection measures at Almondbank, Craige Burn, three flood storage ponds at Broxden, and two reservoirs located at South Inch Park and North Muirton. 4.3 The term surface water flooding is often used to describe the complex interaction of many sources of flooding as a result of rainfall run-off flowing overland, exceedance of small urban watercourses (including culverted watercourses) or artificial drainage systems (e.g. combined sewer), and groundwater. 4.4 In December 2021, consultant engineers, Amey Consulting Ltd were engaged to carry out a SWMP for Perth. 4.5 Amey’s investigations involved extensive data gathering and analysis, consultations, topographic surveys, a hydrological assessment, hydraulic modelling, an environmental desk study, an options study, an economic appraisal and the production of final reports. 4.6 This work built on the numerous existing investigations into surface water flood risk across Perth. This included the Perth Integrated Catchment Study (ICS) carried out by Scottish Water in partnership with PKC, and more targeted investigations at areas of known risk (such as Feus Road and Bridgend), as well as the recent Craigie Burn flood protection study. The existing integrated hydraulic flood model developed as part of the Perth ICS (and updated for the Craigie Burn flood protection study) was reviewed and updated in line with the latest approaches for surface water modelling enabling the best available representation of the surface water risk at a city- wide scale.
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4.7 The SWMP analysed the integrated flooding mechanisms affecting Perth and a series of flood maps were produced. This work provided a detailed understanding of surface water flood risk across Perth. As part of this, areas of highest surface water flood risk across this city were highlighted (referred to as ‘flooding hotspots’). A total of 60 hotspots were identified. A plan showing the location of these is provided in Appendix 1. 4.8 The SWMP hydraulic model identified that pluvial flooding accounts for approximately 22% of the flood risk across Perth. A total of 405 properties are potentially at risk from surface water flooding during a 1 in 30-year flood event (the flood event with a 3.33% chance of occurring in any one year). In future, for this same magnitude of event, the number of properties is estimated to increase to 1,041 properties due to the effects of climate change. A total of 1,217 properties are potentially at risk during a 1 in 200-year flood event (the flood event with a 0.5% chance of occurring in any one year). In future this is estimated to increase to 2,198 properties due to the effects of climate change. 4.9 The 60 flooding hotspots cover the majority of properties identified at risk of surface water flooding across Perth. For the modelled 1 in 30-year flood event (the flood event with a 3.33% chance of occurring in any given year), 369 of the 405 properties identified at risk are contained within a flooding hotspot (91% of the total properties). During the modelled 1 in 200-year flood event (the flood event with a 0.5% chance of occurring in any given year), 988 of the 1,217 properties identified at risk are within a flooding hotspot (81% of the total properties at risk during this event). 4.10 In managing flood risk, the Council is required to have regard to the economic, social and environmental impact of its actions. The Scottish Government’s guidance recommends that decision making in flood risk management should be supported by an options appraisal. 4.11 An options appraisal includes a cost-benefit analysis and other techniques to determine whether a flood protection scheme meets its objectives, is sustainable and represents best value for money. In general, the cost of flood damage avoided over time must be greater than the cost of building the flood defences, i.e., they must achieve a benefit/cost ratio of greater than 1.0. 4.12 Due to the high number of ‘hotspots’ identified, Amey carried out a screening exercise to identify those areas within which there was a realistic chance of identifying viable measures to manage surface water flood risk. This screening exercise selected 29 of the initial 60 hotspots for further multi- criteria assessment ahead of options appraisal. The multi-criteria assessment identified 14 (of the 29) flooding hotspots that had the highest potential to identify viable surface water management measures. 4.13 Areas that have been subject to separate investigations (previous or ongoing) were also screened out. This included areas such as Bridgend, Cavendish Avenue/Gray Street, Feus Road and Marshall Place.
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4.14 An initial long list of high-level options to manage the risk of flooding were considered in the context of each flooding hotspot. Amey undertook an iterative assessment to refine this for more detailed consideration. A long list of 18 options was selected (refer to Appendix 2 for details). 4.15 This long list was assessed through a further multi-criteria (technical, environmental and economic) appraisal to produce a preferred short-list of 10 options which were assessed in further detail. Table 1:Short list summary table Option No Location Option 1 Dupplin Road and Annat Road Disconnection & SUDS 2 Fields near Murray Royal Greenspace Attenuation 3 Connacher Bank retirement living Surface Water conveyance route 5a Oakbank Rd and Cherrybank Grove Disconnection 5b Perth Academy Disconnection and SUDS 7 Millenium Park Greenspace attenuation 12a Rannoch Road (between Newhouse Road and Letham Road roundabouts) Disconnection 12b Rannoch Road (between Letham Road and Unity Terrace roundabouts) Disconnection 13 Whitefriars Industrial park Disconnection / SUDS 14 Dewars Centre/Perth leisure pool Disconnection / SUDS 4.16 The final short list of potential options, together with the estimated costs and benefit/cost ratios, is provided in Appendix 2. 4.17 Further detailed assessment of the 10 short-listed options identified that only two options were considered feasible, both economically and in terms of overall benefit. These were the disconnection and SuDS options at Whitefriars Industrial Park (option 13) and Dewars/Perth leisure pool site (option 14). 4.18 Option 13 had an estimated capital cost of £0.412m with a benefit/cost ratio of 3.4. Option 14 had an estimated capital cost of £0.221m and a benefit/cost ratio of 2.2. No standard of protection can be attributed to these options and the benefit is measured in the overall reduction in annualised average flood damages within the area. Wider benefits of removing surface water from the combined sewer network would also be realised. 4.19 Due to the nature of the recommended options, it has been identified that the best delivery mechanism for these would be through future development opportunities at each site.
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4.19 A means to control delivery is through the next iteration of the local development plan (LDP3), through site specific developer requirements associated to development allocations and through Green-Blue Network mapping and guidance. 4.20 The option at Dewars/Perth leisure pool was initially identified as an opportunity to utilise the significant greenspace at the site in its current form/use. The more recent, and ongoing, wider discussions regarding the future use/redevelopment of this site do not alter these conclusions. There is ongoing dialogue with the Council’s Property section and their drainage and flood risk consultants regarding the future of the site to ensure that flood risk benefits are realised. 4.21 The hydraulic model for the SWMP suggests that much of the main trunk sewers running through Perth are affected by a lack of capacity, leading to significant flooding at vulnerable points where manholes are particularly shallow, or where sewer pipes are (relatively) undersized or have a low gradient. This is a common issue in urban areas due to the historic approach of using one ‘combined’ sewer system to deal with both foul and surface water. Prior to the legal requirement of SuDS for new developments, this approach increased pressure on these systems, and more recently, climate change has become the main factor in reducing the relative capacity of sewer systems. Due to the limited areas across the city to store surface water above ground, particularly around the areas of highest risk, alleviating this risk typically requires significant infrastructure upgrades to enable storm flows to be drained. These measures are prohibitively expensive and often face technical challenges (spatial constraints and conflicts with buried utilities). Scottish Water are required to undertake assessments of sewer flood risk, as a prescribed action within the Tay Local FRM Plan and in line with their duties under section 16 of the Flood Act. 4.22 The SWMP highlights a number of ongoing projects/proposals which will help manage overall surface water flood risk in Perth, namely ongoing Scottish Water investment projects at Feus Road, Cavendish Avenue and Bells Sports Centre. The Council has developed a detailed design for flood protection works at Bridgend, but this is currently on hold due to delays in funding of Cycle 2 schemes as a result of the ongoing discussions between Scottish Government and CoSLA. 4.23 The SWMP also recommends other non-structural actions that align with on- going actions to manage flood risk under the Tay Local FRM Plan. This includes ensuring local and national planning policies are applied with regards to surface water management in new developments. 4.24 The SWMP advises that property flood resilience measures are an effective tool to improve the overall flood resilience of the city. It recommends the uptake of these measures by property owners in areas of surface water flood risk, with a preference for passive measures (e.g. flood doors, automatic air brick covers etc) due to the speed at which surface water flooding can occur.
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This recommendation is in line with the recently published National Flood Resilience Strategy. As part of the 2026-27 budget, the Council has approved initial funding to support a Property Flood Resilience Grant that residents will be able to apply for to assist with the costs of installing appropriate measures at their property. 4.25 In order to disseminate the findings of the SWMP, and to outline how flood risk is being managed in the area, a newsletter summarizing the work was published on the Council’s consultation hub (https://consult.pkc.gov.uk/communities/perthswmp) during the period 1 October to 30 October 2025. The consultation period allowed residents to view the draft outputs from the SWMP, speak directly to council officers, design consultants and other agencies such as Scottish Water and Scottish Flood Forum. Residents were encouraged to provide feedback on the surface water management plan recommendations. 4.26 A community drop-in session was held at the Dewar’s Centre on 29 January 2026. The community drop in event was attended by approximately 30 people, although only 14 people recorded their attendance via a sign in sheet. The majority of attendees had previously submitted online feedback and took the opportunity to follow up directly with Officers. It should be noted that six attendees were from areas out with the Perth SWMP study area and advised that they attended to better understand the process in advance of another SWMP that was being carried out for their locality. 4.27 The feedback received during the consultation events or through submitted comment forms covered a range of topics including the study methodology, options appraisal and recommendations, as well as around existing maintenance arrangements, new development and Scottish Water infrastructure. 4.28 A ‘Question & Answer’ report addressing the main comments raised during the consultation period was disseminated to all respondents and is available to view on the Consultation Hub (https://consult.pkc.gov.uk/communities/perthswmp). The comments raised were relevant and informative but did not fundamentally alter the conclusion and recommendations of the SWMP. 4.29 SWMPs should be monitored, reviewed and updated to align with the six-year Flood Risk Management planning cycle. The next update is likely to be required in Cycle 3 (2028-2034). 5. Proposals 5.1 The SWMP does not recommend any standalone proposals and identified collaborative opportunities that should be explored at the relevant time through LPD3 and planning applications as they come forward to provide surface water flood risk benefits.
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The mechanisms for this will likely be through site specific requirements associated to development allocations and Green-blue network mapping and guidance. 6. Conclusion 6.1 This report provides an update on the outcome of the Perth Surface Water Management Plan (SWMP). 6.2 A surface water management plan was identified for Perth within the Tay Flood Risk Management Plan and Local Flood Risk Management Plan. The Council engaged consulting engineers, Amey Consulting Ltd, to deliver the SWMP. 6.3 The Council’s consulting engineers have not identified a feasible flood protection scheme to manage areas at surface water flood risk in Perth. However, the SWMP identified two areas where a significant reduction in economic flood damages can be achieved through surface water separation from the combined sewer and retrofitting SuDS. The potential redevelopment of sites at Dewar’s and Whitefriars provides the opportunity to realise the identified benefits. 6.4 The SWMP reiterates the benefit of property flood resilience measures, recommending further uptake by residents in areas at risk of flooding, in line with the Scottish Government’s National Flood Resilience Strategy. The Council has recently approved funding for a Property Flood Resilience Grant that will support residents with the costs of installing appropriate measures. 6.5 The SWMP also builds on and aligns with the Flood Risk Management Actions centred on Community Engagement (i.e. sharing of information and advice) and Community Resilience Groups (i.e. those community led groups supported by the Council to develop resilience and flood protection on a local scale). 7. Impact and Value Assessment This report has been classified as being an operational report and as such does not require a full Impact and Value Assessment. 8. Appendices - Appendix 1: Perth SWMP 0.5% AEP flood map and hotspots - Appendix 2: Perth SWMP Options