Agenda item

To discuss flood risk management with representatives of Thames Water and the Environment Agency

The Director of Environment, Culture and Communities introduced the item by reminding members about the Council’s Flood Risk Management Strategy. The Emergency Planning Manager summarised the Council’s role in partnership with external agencies. Bracknell Forest experienced fewer flooding incidents than nearby boroughs, and priority was given to protecting residential dwellings and highways.

Jeanne Capey and Melanie Ward of the Partnership & Strategic Overview Team at the Environment Agency (EA) gave a presentation on Flood Risk Management.

The Risk Management Authorities were: the EA, Lead Local Flood Authority, District council/Unitary Authority, Internal Drainage Boards, Water Companies, and the Highways Authority.

The role of the EA was to take a strategic overview of flooding and support and co-operate with other risk management authorities in carrying out their functions; Support partnerships at both a strategic and operational level; and Develop a national FRM strategy for flood risk management.

Strategic Partnerships brought together Risk Management Authorities, Strategic leadership, and were important in delivering FWMA requirements and allowing organisations to be efficient and effective.

The EA would develop a National Strategy for Flood and Coastal Risk Management in England; provide a framework for the work of all flood and coastal erosion risk management authorities; set out the long-term objectives for managing flood and coastal erosion risks and the measures proposed to achieve them; and encourage more effective risk management by enabling people, communities, business and the public sector to work together.

Risk management authorities had powers and responsibilities to manage flood risk and work with others to improve the river environment in England and Wales. The EA, local authorities and internal drainage boards were all risk management authorities. The work of risk management authorities often affected riparian owners and people who lived nearby.

The EA had powers and responsibilities to maintain and improve main rivers throughout England and Wales. They also had a responsibility to manage flood risk from main rivers and the sea. Lead Local Flood Authorities had powers to manage flood risk from ordinary watercourses, surface water and groundwater.

Land owners with land adjoining a watercourse had certain rights and responsibilities. In legal terms they were a 'riparian owner' and responsibilities included: maintaining river beds and banks; allowing the flow of water to pass without obstruction; and controlling invasive alien species such as Japanese knotweed.

The main rivers in Bracknell Forest were the Cut which ran along the North and its smaller tributaries, the Bull Brook in the centre of Bracknell and the Blackmoor Stream on the border in North Ascot. Also, the River Blackwater in Sandhurst at the South of the border. There were historic records of main river flooding from the Cut in 1947, 1974 and 1981 and The River Blackwater in 1947.

The EA routinely considered dredging and other types of watercourse management, such as de-silting and vegetation removal, to reduce flood risk. Work was undertaken where it was: Technically sound, economically viable, and environmentally acceptable and sustainable.

Watercourses were checked yearly by the Asset Inspection and Enforcement team, and they would then highlight any issues to us to inform the land owners. The EA did not own any assets in Bracknell Forest. The EA’s priority was to maintain the existing conveyance of the main rivers and where possible increase its efficiency. This would be undertaken through an annual programme of bank and in-channel weed clearance and the removal of obstructions.

The EA had compiled Communities at Risk packs for West Berkshire Local Authorities. The Bracknell Forest pack included a summary of the fluvial flood risk within Bracknell Forest. It showed how the amount of fluvial flood risk compared throughout Bracknell Forest and the other Local Authority areas in Berkshire. It also highlighted the key areas of risk. The risk of flooding in Bracknell Forest had been assessed by the EA as low.

The EA had to produce and publish flood risk information by 22 December 2013 to meet the requirements of the Flood Risk Regulations, which was essentially updating the way the EA published its information. Regulations required the EA to produce ‘hazard’ and ‘risk’ maps of where gets wet, the extent, depth or level, flow or velocity; Maps of what gets wet, receptors such as people and infrastructure; and the sources of water, for example, rivers & sea, reservoirs, and surface water (in Flood Risk Areas).

In response to Members’ questions, the following points were noted:

• Clearer copies of the images used in the presentation were requested by the Chairman and would be provided to panel members.
• The Bull Brook did not feature in the presentation as it was not designated as a main river.
• Hydromorphological status referred to the status of a river.

Keith Herbert, Field Services Manager, Mark Dickinson, Development Planning Manager, and Hilary Murgatroyd, Local / Regional Government Liaison from Thames Water gave a presentation on Managing Flood Risk in Bracknell Forest.

Thames Water:

• Was the UK’s largest water and wastewater services provider;
• Had 14 million customers;
• Had 4,500 employees;
• On average of 2,600m litres of drinking water were supplied each day;
• Had 100 water treatment works;
• Had 350 sewage works treating over 4 billion litres per day;
• Had 66,500 miles of sewer, 2,530 pumping stations and 1.2 million manholes.
• Covered areas between Reading, Swindon, Oxford, and Banbury. It also covered Guildford, and London, but other water companies covered areas in between such as Basingstoke, Luton and Stevenage.

Thames Water was appointed under the Water Industry Act 1991 to be responsible for sewerage and had a duty to provide public sewers and to clean and maintain them, and a duty to provide and extend sewerage systems. There are three types of sewer: Foul water sewers, Surface water sewers, and Combined sewers. Foul water sewers carried water that had been used for cooking, washing and from toilets, to the sewage works. Surface water sewers carried water from roofs, some roads and other hard standing areas and returned it to a watercourse. Combined sewers carried both (mostly in London).

Types of Flooding included Hydraulic Flooding caused as a result of incapacity within the network and normally linked to excessive rainfall events, and Operational Flooding caused as a result of operational failures such as sewer blockages sewer collapses or pumping station failures.

It was important that customers reported incidents to 0845 920 0800. Operations would be undertaken to investigate and determine the cause; flooding events of less than 1 in 10 would be prioritised; and a scheme to reduce risk of flooding was designed, 1:30. The cost and benefit of the scheme would be calculated and where it met regulatory requirements the scheme could be built.

The network in Bracknell Forest was relatively new and sustainable urban drainage was the approach undertaken. Retention (balancing ponds) in Bracknell Forest attenuated the flow during flash flooding and released rain water slowly. Thames Water had recorded just 68 property floodings in the borough, which was not regarded to be a significant level.

Sewerage issues in the Bracknell Forest area included: operational use of balancing ponds and common problems were silt, vandalism, responsibilities under the Reservoir Act, ownership and usage disputes, algae, and grounds maintenance.

Thames Water were operating a ‘Bin It Don’t Block It’ campaign. 75% of sewer flooding was caused by blockages in the sewer. Inappropriate items included: fat and oil, wet wipes, sanitary items, nappies, kitchen roll, food waste, incontinence products, colostamy bags, cotton wool, cotton buds, razor blades, tights, plasters and bandages, condoms, dental floss, medicines and tablets, engine oil, chemicals and paint.

In response to Member’s questions, the following points were noted:

• In Bracknell there was a low level of complaints made regarding sewage issues.
• The flow in balancing ponds should be fairly consistent or not at all. Balancing ponds were inspected every three months but not the flow specifically. There were not many blockages on the surface water network, they were mainly from silting or collapses.
• All flooded properties received priority and the same response to flooding issues.
• The Lead Flood Authority would call on partners when needed and colleagues would work together on an operational basis.
• If people were unsure as to who to contact regarding a flooding issue, they could contact their local council or councillor and be pointed in the right direction, for example, the Environment Agency dealt with main rivers.
• The team at Thames Water were fully engaged in the planning process from extensions to larger developments. They commented regularly on housing developments but did not have statutory consultee status. Thames Water covered 93 local authorities.
• The Environment Agency commented on flood risk and surface water risk.
• There had been vandalism problems and a project had been introduced where signage had been erected at the balancing ponds to try to improve the situation. The aim was to resolve problems with the balancing ponds as quickly as possible. The community could proactively manage the ponds themselves if they wished.

Councillor Kensall referred to a report he had produced concerning the Bull Brook, and raised three issues in that regard:

·         There were concerns about the ownership and responsibility of the Hydro Break and Trash Screen at the Letcombe Square crossing. Thames Water representatives described their routine inspection and maintenance arrangements and undertook to arrange for this part of the watercourse to be cleared again.

·         Councillor Kensall referred to the dry balancing pond and connecting water culvert, saying that the culvert was clogged with years of debris, silt, soil, long grass and trees. The bed of the dry balancing pond appeared to him to have risen by at least one metre and was also now clogged with tangled undergrowth and trees. He requested Thames Water to dig out and clear the connecting water culvert as soon as possible and to conduct a survey to establish the capacity of the dry pond area. Thames Water agreed to conduct a survey of the dry pond area.

·         Councillor Kensall drew attention to the final trash screen where the stream returned to the surface water sewage system as being on Network Rail land, and asked about ownership, responsibility, and access to this area. The Council's Drainage Officer informed the Panel that he was arranging a separate meeting with all relevant agencies to discuss the issues raised about The Bull Brook Stream.

The Chairman thanked the representatives from the Environment Agency and Thames Water for their presentations.