Transport & Sustainability Committee
Agenda Item 71
Subject: Gully Cleansing Strategy Update 2024
Date of meeting: 6th February 2024
Report of: Executive Director Economy, Environment & Culture
Contact Officer: Name: David Fisher & Stacey Hollingworth
Email: David.fisher@brighton-hove.gov.uk & stacey.hollingworth@brighton-hove.gov.uk
Ward(s) affected: All
1.1 This report was requested via a Notice of Motion at Full Council on 14th December 2023 in response to political concerns about the number of blocked gullies and drains in the City.
1.2 The cost of providing the cyclical gully cleansing service more than doubled on the 1st November 2022 from £154k/year to £318k/year. The increase was the combined result of increasing costs across the industry, rising inflation, and the signing of a new NEC Highways Framework Contract. The previous contract had been in place for 8 years and no longer represented current market rates for the delivery of this service.
1.3 This report provides an update on how the previously approved Drainage Strategy has been implemented and how the risk-based approach has been applied to this service to ensure value for money and to ensure that it can continue to be delivered within existing revenue budgets. It also sets out the other factors that influence surface water and what actions are in place to address these challenges within existing budgets and resources across the relevant teams within the Council.
1.4 This report follows on from the approved Highways Asset Management Policy and Strategy 2023-2025 that set out the Drainage Strategy and the need to enhance the existing risk-based approach for gully cleansing using the latest condition data.
2.1 That Committee notes the change in the cleansing regime in response to increased costs within the industry as detailed in paragraphs 3.5 to 3.13 of this report.
2.2 That Committee notes the various factors that contribute to surface water flooding and the mitigation that is in place as set out in Appendix 1 of this report.
2.3 That Committee notes the drainage infrastructure maintenance backlog of £1.25 million as detailed in paragraph 4.2 of this report.
3.1 On 14th December 2023, a Notice of Motion was agreed at Full Council which resolved to:
“1) Have an officer report brought to the next Transport and Sustainability Committee outlining an action plan to improve and increase the clearing of blocked gullies and drains across Brighton and Hove, subject to funding.
2) Ensure that in the next update report to Transport and Sustainability committee, officers detail the approach to prioritising high-risk areas for regular clearance; the financial implications of the ongoing maintenance and clearing programme; and how the council will work collaboratively with Southern Water to alleviate pressure on the system through deployment of SuDS at strategic locations.”
3.2 The Council as the Local Highway Authority is responsible for draining the surface of the Highway for the benefit of the travelling public as standing surface water has the potential to:
· act as a lubricant which can reduce the effectiveness of tyre grip increasing stopping distance.
· increase the risk of aquaplaning and skidding on ponding water.
· contribute towards damage to the highway surface or sub-structure, so shortening the lifespan of the carriageway construction.
3.4 Cleansing gullies to remove accumulated silt is only one method for managing surface water on the Highway. Other key factors that significantly impact surface water drainage include:
· An increase in extreme rainfall events caused by climate change
· Leaves and detritus on top of the gully preventing water from flowing into the gully
· Increase in hard surfaces with insufficient drainage, from private land. e.g. driveways
· Construction and Commercial waste being discharged into the drainage system
3.5 In November 2022, the contract cost of cleansing gullies doubled from £154k/year to £318k/year which meant that the service had to be reviewed and the risk-based approach updated to ensure that the service could be delivered within the existing budgets. The budget for the delivery of cyclical gully cleansing is £154K per year. The budget for non-cyclical gully cleansing has historically been held within the wider Safety Maintenance budget and spends have varied annually depending on the needs of the network. Due to competing demands for the safety maintenance budget due to increased costs in all areas, the budget for non-cyclical gully cleansing will need to be capped and therefore the total available budget for both cyclical and non-cyclical gully cleansing is £230K/year.
3.6 The condition of gullies, including silt levels, is recorded at the time of cleansing which is undertaken by our Term Contractor and is recorded on their asset management system - Map16. We currently have over 10 years of historical data which has been used to carry out lifecycle planning analysis of our drainage assets. The desired drainage outcome is to ensure that efficiency and effectiveness are balanced appropriately to make the best use of limited budgets.
3.7 An effective risk-based approach based on good quality data is a requirement of the Well-managed Highway Infrastructure Code of Practice 2016 and allows the Council to focus maintenance budget on the higher priority assets which may pose a greater risk of flooding and disruption to road users.
3.8 In 2016, the Council commissioned Project Centre Ltd in collaboration with Metis Consultants Ltd to undertake a risk-based study of Brighton and Hove’s highway drainage assets. The study aimed to provide a prioritised list of road sections to incorporate into Brighton and Hove’s drainage cleansing and inspection regime for gully and soakaway assets.
3.9 The Council's policy at that time resulted in a cleansing schedule where most gullies were routinely inspected and cleansed every 18 months with 5230 gullies cleansed annually.
3.10 In 2023, the Council carried out further analysis of the condition of all drainage assets to ensure that the limited budgets could be managed efficiently and effectively.
3.11 The latest silt analysis provides a robust justification and scope to alter the current gully cleansing frequencies in line with available budgets. This shift allows more silt accumulation before the assets are cleaned without the risk of assets being blocked prematurely before their next cleanse date.
3.12 This means that gullies in the vicinity of properties that have historically been affected by surface water flooding will be cleansed twice a year compared to every 18 months under the old regime. Others will be cleansed annually, biennially or every four years based on historic silt data and the potential risk at each location. The prioritisation also takes into account high-risk flooding routes identified as part of the Climate Risk and Vulnerability Action Plan e.g. A270 Lewes Road and A23 will now be cleansed every 12 months. However, a further review will take place, if the report is approved, to ensure that the key risks and actions are incorporated into the gully cleansing programme.
3.13 The cost of delivering the updated cyclical gully cleansing programme is £164K including contract costs.
3.14 Appendix 1 details the current flood mitigation measures in place to manage the other significant causes of surface water flooding as referred to in paragraph 3.4 of this report.
Impact of Parked cars on the gully cleansing service
3.15 At Full Council on 14th December, Elected Members raised concerns about the potential impact of parked cars on our ability to cleanse gullies.
3.16 The latest data shows that only 8% of the network could not be cleansed as planned due to parked cars. Of the locations that were inaccessible due to parked cars, 1% were observed to be running with no problems, just over 2% were observed as being fully silted and 5% could not be visually checked. We currently manage this relatively small risk by allocating a proportion of the remaining budget (up to £5k/month) to carry out ad-hoc cleansing. Due to the monthly limit on this budget, ad-hoc cleansing can only take place in genuine emergencies.
3.17 A genuine emergency is defined as:
· Flooding of homes/premises not caused by extreme weather events.
· A genuine safety hazard to road/pavement users which is frequent and lasting (i.e. does not disappear within 48 hours of heavy rain ceasing).
3.18 Whilst high-risk areas are prioritised within the cyclical gully cleansing programme based on the available data, as the Highway Authority, we are unable to prevent flooding caused by extreme weather events and we are not responsible for the impact this has on properties that sit below the road level.
4.1 The current approach to gully cleansing is based on good-quality historical data on silt levels and represents the best balance of efficiency and effectiveness to make the best of the budget that is available. By improving the efficiency of the service we were able to improve the service by increasing the cleansing frequency of high-risk sites and reducing the frequency of low-risk sites based on the data available. We will continue to review new data as it is collected with our term contractor to ensure that the service continues to be optimised.
4.2 If additional funding was available, then this would be best used to clear the backlog of infrastructure maintenance including investigating and resolving blocked outlets (676 sites) and repairing broken/jammed gully grids (948 sites). The total cost to clear the maintenance backlog is estimated at £1.25m.
4.3 Additional funding could also be used to introduce a regular programme of leaf removal at the 61 high-risk sites throughout the winter period at a cost of £27K/year. See Appendix 1 for further details about the approach to leaf clearance.
4.4 The issue regarding parked cars impacting on gully cleansing is not unique to this Council. Local Authorities take different approaches but feedback from our term contractors across their range of clients suggests that none have found a solution that works effectively. In the past, along with other authorities, we have asked the contractor to attend up to three times for each location however experience has shown that the success rate of the three visits is low compared to the cost and mileage required to achieve this.
4.5 Notifying residents in advance of a gully cleansing visit and providing a car lifter would cost in the region of £1000/week which would be cost prohibitive and experience from other authorities suggests that notifications alone are unlikely to be effective.
4.6 The most cost-effective and sensible approach is therefore to take a risk-based approach and only revisit sites where there is a genuine issue using the ad-hoc cleansing budget referred to in paragraph 3.16.
4.7 Council Officers do however meet the term contractors regularly and are committed to continuing the discussions to identify additional actions that could be taken to further mitigate the impact of parked cars. Officers will also raise this issue at the next LCRIG South-East Gulley Monitoring Sub-Group meeting to discuss best practice and any new approaches within this area.
5.1 The maintenance of the drainage network is a statutory duty and therefore does not require consultation in the same way as the delivery of projects however we are fully committed to collaborating and learning from key organisations and partners. We also listen and respond to requests from the public and action them as appropriate.
5.2 The Council are members of the South-East 7 Alliance and the South-East Local Council Roads Innovation Group (LCRIG) and attend regular meetings with both organisations to share best practice and innovation with neighbouring authorities. The Council are also members of LCRIG South-East Gulley Monitoring Sub-Group which meet specifically to discuss approaches to maintaining and cleansing gullies.
5.1 The Council is the Lead Local Flood Authority as defined by the Floods and Water Management Act 2010. As part of this act, there is an expectation that a relevant authority must co-operate with other relevant authorities in the exercise of their flood and coastal erosion risk management functions. As such the Council meets with representatives from Southern Water for general coordination meetings as often as is practical and also has a close working relationship with the Catchment Engineer within Southern Water. This relationship is key when preparing for planned flood events. For example, when the trigger points were reached for Patcham flooding, the Catchment Engineer opened the covers to the sewer and reported back the water levels to the Flood Risk Management Team. They also provide information about the volumes in the stormwater sewer along the seafront. The Catchment Engineer has also recently attended a joint site meeting with the businesses of Preston Circus.
5.2 As recommended in the Climate Risk and Vulnerability Action Plan, we will continue to build collaboration with other local, regional and national stakeholders.
5.3 The Council takes part in the Annual National Highways and Transport Network Survey which consults local residents on all aspects of the City Transport Service. The latest results from 2023 showed 38% of respondents from Brighton and Hove were satisfied that drains were being kept clear and working which is a 10% decrease on the previous year and 2% lower than the national average. This drop in satisfaction suggests that the previous arrangement was not meeting expectations and therefore we will be able to monitor any change in opinion as a result of the updated approach when the 2024 results are released.
5.4 Resident can report drainage concerns via a form on the Council’s website where they will be responded to by the relevant team.
6.1 The Council takes a risk-based approach to the cleansing of gullies which is a requirement of the Well-managed Highway Infrastructure Code of Practice 2016. This approach allows the Council to focus the available maintenance budget on the higher priority assets which may pose a greater risk of flooding and disruption to road users.
6.2 Whilst it is acknowledged that parked cars do impact the Council’s ability to deliver the gully cleansing programme, the data shows that the overall risk is relatively small. This small risk is mitigated as part of an ad-hoc cleansing service that focuses on investigating and resolving emergency flooding issues that occur outside of the cleansing programme.
6.3 Gully cleansing is only one method for managing surface water on the Highway. Council Teams work together to mitigate these issues as much as possible within the budgets and resources available as detailed in Appendix 1.
6.4 There is however a £1.25m maintenance backlog of the drainage asset infrastructure. Should additional funding be made available in the future then this could be used to clear this backlog by investigating and resolving blocked outlets and repairing/replacing broken gully lids. Additional funding of £27K/year could also be used to fund a regular programme of leaf removal from high-risk gully locations during the winter period.
7.1 There are no direct financial implications arising from the recommendations of this report which is for noting. The risk-based approach is mitigating increased costs of providing gully cleansing to ensure the service can be delivered within existing revenue budgets. £0.100m is allocated within the Local Transport Plan Capital funding for drainage works in 2023/24. Any significant variation to budget will be reported as part of the council’s monthly budget monitoring process.
Name of finance officer consulted: John Lack Date consulted: 22/01/2024
7.2 This report is for noting and there are no direct legal implications arising from it as a result. However of general note is that the Council as local highways authority has a duty under the Highways Act 1980 to keep the highways in its administrative boundary in a condition that is safe and fit for purpose. Gully cleaning is one of the mechanisms used to achieve this.
Name of lawyer consulted: Katie Kam Date consulted 22/01/2024):
8.1 This report summaries the existing approach to drainage and therefore does not have any new Equality implications beyond what has already been reported as part of the Highway Asset Management Policy and Strategy in January 2023.
10.1 This report summaries the existing approach to drainage and therefore does not have any new sustainability implications beyond what has already been reported as part of the Highway Asset Management Policy and Strategy in January 2023.
Supporting Documentation
1. Additional Flood Mitigation Measures