Here you will learn about the adaptation approaches that can be used to reduce the impacts expected from climate change by the 2050s on flooding from streams, rivers and the sea, flooding from drainage systems and impacts on flood defence structures.

 

 

Flooding from rivers and the sea
Flooding from the rivers, streams and sea is generally pro-actively managed by the appropriate authorities as part of well-established flood risk management programmes.  These include long-term and strategic planning, flood warning systems, and the development and maintenance of appropriate flood risk management solutions.  A sixth of the region’s land is within the tidal or fluvial floodplain and more than 285,000 people are currently live in an area at risk.  There are around 1,700 km of flood defences, and £24 million is spent each year on the development of further defences.  In addition, more than 205,000 properties (70% of those at risk) are currently covered by the Environment Agency’s flood warning service (although not all of these are registered to receive warnings).

Typically, these activities inherently consider the likely effects of future climate changes and are planned to continue into the future as part of central government’s approach to flood risk management.

The Regional Flood Defence Committee and Environment Agency have various flood risk management projects scheduled in their current programme for implementation.  Of particular note are the following:

• The Humber Strategy – considering the future management of flood defences along the estuary, to continue the protection provided to 99% of inhabitants, and the development of managed realignment areas to create 1,000 hectares of additional inter-tidal habitat.
• Development of new strategies for flood management to return certain agricultural floodplain land in to washlands to provide increased protection to surrounding urban areas.
• Flood defence scheme through Leeds city centre to raise the current flood defences and provide additional upstream storage (£80 million, to start 2011).

There are many adaptation measures that should continue to be incorporated in this approach.  These include measures at a strategic planning level down to flood defence provision and forecasting significant events.

More detailed assessments incorporating detailed hydrological and hydraulic modelling could be used to identify the numbers of properties at risk under future climate scenarios.  This could also involve identifying the criticality and vulnerability of key public infrastructure (electricity, gas, water supply, sewage works, telecommunications, transport, schools) and producing improved regulations for their ongoing protection from flooding. The risks need to be considered cross-organisationally to identify key interdependencies. 

Improved regulation and guidance should be provided across all sectors for consideration of the impacts of flooding due to climate change.  Many regulators are not currently engaged in the debate on climate change and its inclusion in their requirements and recommended guidance, i.e.  OFWAT, Rail Regulator, Housing Corporation. 

Developments allowed within the flood plain corridor should continue to be tightly controlled and it may be necessary to relocate key industries and critical/vulnerable properties away from areas of potential flood risk, particularly in situations where it is inappropriate or unsustainable to provide defences.  The protection of properties and assets in the event of flooding should be determined, with top priority given to the protection of critical infrastructure and key access routes; followed by vulnerable populations; followed by flooding to residential property.

Existing flood defences should be maintained in locations where this is economically justified and, where necessary and cost-effective, improved to raise standards of protection.  More innovative and sustainable flood management approaches in some situations may provide a more effective solution.  This might include upstream storage of flood water and the further use of washland and managed realignment areas.  Partnership approaches and cross-sectoral responses to reduce potential flooding should be established, and these might provide multiple adaptation benefits, such as water stored in upland areas being used to fight potential fires caused by higher summer temperatures. 

Local land management changes in rural areas could be used to reduce rates of surface runoff, such as the provision of hedgerows and ditches and the lateral ploughing of fields along contours to reduce field runoff and the wash off of sediments and retain nutrients on the fields.  (The current Forestry Commission study in Pickering and other Natural England Higher Level Stewardship schemes are currently looking into these and other aspects).  The encouraged use of managed realignment areas also has benefits with flood waters bringing nutrients onto the fields.  Also the benefits of flood risk management through increased woodland creation up catchment or on the local flood plain should be considered, which may reduce flood risk and potential for channel erosion.

The future planning and management of caravan and camping sites, which are highly vulnerable to flooding impacts, should be improved as tourism increases.  Low volume sites are not currently subject to planning permission due to their temporary nature and sites are often placed at high flood risk near watercourses and the sea.

New developments should move away from lowest cost to more adaptable and sustainable developments, with the inclusion of sufficient resilience as necessary for the location.  Flood proofing and resilience for properties and homes such as raised electrics and raised sub-floors (for post-event draining) could be incorporated into designs.  Retrofitting older properties could be carried out during any refurbishment work. 

Also, new roads and railway sections could be constructed at raised levels (on stilts or viaducts) in flood prone areas.  Existing main routes already affected could be bypassed and then improved in a similar fashion.

Multi-agency response plans should be produced in order to co-ordinate responses during extreme events.  The availability of response units and equipment such as high volume pumps and boats could be improved.  Temporary or demountable flood defences could be made available to low impact areas frequently affected by flooding, with clear access routes permanently available for their installation.  All agencies should look at ways to educate the wider public and promote the development of flood resilience measures for properties at risk.

The maintenance of watercourse channels to remove vegetation and blockages should be increased in order to retain flow capacity, where this is economically justified.  Public campaigns could be used to reduce fly tipping and clear rubbish from watercourses, reducing flood impacts during flash summer events and increased winter rainfall.

Monitoring and flood warning particularly in upstream areas and on unpredictable permeable chalk catchments should continue to be improved upon to provide emergency warnings as much in advance as possible of flooding events.

Surface water/Drainage
New drainage schemes and improvements may often incorporate some consideration for climate changes based on current best practice guidance.  Existing systems, however, are generally managed in a more reactive sense, although drainage area plans produced by the water companies should highlight areas most likely to be at risk.  The key action that could be taken would be to assess all systems likely to affect large numbers of people based on local climate changes, rather than general guidance values, to determine future areas at risk. 

With respect to drainage systems, a clear co-ordinating framework between local government, water companies, the Highways Agency and the Environment Agency is required for managing the flood risk from surface water drainage.  (This is currently being developed to some degree through Surface Water Management Plans, Integrated Urban Drainage projects, and Water Cycle Studies).

Current design standards should be appropriate and locally relevant to accommodate future increases in rainfall and runoff.  The current planning requirements for new sewer designs are outdated.  Designs often use old rainfall data and are required to a 1 in 30-year standard.  Yorkshire Water often designs its new sewers in flood –prone areas to accommodate increased future flows.  Improvements across the drainage network should be strategically planned and implemented on a risk-based approach, although increasing pipe sizes across the entire network would clearly be impractical and investment would be better focussed on areas at greatest risk.  Drainage for new build developments should ideally follow sustainable drainage (SUDS) techniques to attenuate runoff at source, or where this is not appropriate incorporate additional capacity within their design.  Additionally, the capacity of existing systems should be improved where necessary to accommodate for predicted increases in rainfall.  

Downstream impacts from new drainage systems should be limited by designing the systems with over-sized pipe diameters and manholes to deliver a limited maximum appropriate outfall discharge, such as equivalent to normal greenfield runoff, as currently generally applied in the design of highways improvements.

Investment into the wider application of source control techniques should be encouraged to attenuate flow volumes earlier in the system and reduce downstream impacts on existing ageing sewer networks.  This would also have the added benefit of reducing the impacts of peak flood flows in problem watercourses.  There are ongoing questions over the practicability of implementing such methods which need to be resolved, due to ownership issues and planning policy guidance requiring increasing numbers of houses with less available space between.

Investigation of opportunities for the management of combined flooding from different sources, such as the recent Defra Integrated Urban Drainage pilot schemes, should be considered.  (There are two such schemes currently underway in Bradford and Garforth, Leeds).  The retrofitting of SUDS (sustainable drainage systems) should be incorporated for an overall reduction of urban runoff, again reducing peak flow impacts to downstream watercourses.  Opportunities to retro-fit existing infrastructure may be a costly solution, but could include the retrofitting of balancing tanks into historic drainage systems in known flood areas in order to accommodate excess flows when sewers reach capacity.

To counteract the effects of development creep, i.e. gardens being paved over, households across residential areas could be provided with water butts for collecting rainwater.  The public could be educated on the importance of SUDS, source control of flooding and the wider impacts of paving over garden areas.

Sufficient flood-proofing of infrastructure and equipment at Sewage Treatment Works and Pumping Stations should be provided to accommodate greater flows.  CSOs should be improved in key environmentally sensitive locations where increased spills are likely to have detrimental effects.  Outfall capacity should be improved, storage provision increased or pumping included at CSOs likely to be affected by climate changes due to sea level rise or raised flood depths.  The design of fluvial flood defences should consider the impacts of raised water levels on adjacent CSOs.

Remote vulnerable properties should be flood-proofed where improvements to drainage systems would be uneconomic. 

Where this is feasible, improvements could be made to the current flood warning systems, particularly in fast reacting catchments, to introduce new early warning systems specifically to deliver warnings in surface water flooding prone areas.

 

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| North Yorkshire | West Yorkshire | Humber | South Yorkshire |

 

Flooding from rivers and the sea
Flooding from the rivers, streams and the sea is generally pro-actively managed by the appropriate authorities as part of well-established flood risk management programmes.  These include flood warning systems, long-term and strategic planning, and the development and maintenance of appropriate flood risk management solutions.  Typically, these activities inherently consider the likely effects of future climate changes and are planned to continue into the future as part of central government’s approach to flood risk management.

Further detail on the adaptation responses that are proposed by the Environment Agency for the North Yorkshire area over the next (nominally) 100 years are presented in the local Catchment Flood Management Plan (CFMP) documents that have been produced by the Environment Agency: the Aire CFMP (including the Ribble), Yorkshire Ouse CFMP, Esk and Coastal Streams CFMP, and Derwent CFMP.  These documents are soon to be finalised and will be publicly available.

In particular, the following adaptation measures should continue to be incorporated in this strategic approach; however individual Local Authorities should look to develop their own adaptation and flood response plans in relation to all aspects of flooding to be more specific to their own requirements.

• Continue monitoring and flood warning for river and tidal events, particularly in upstream areas due to specific issues and the nature of flooding.
• Incorporate more detailed assessments of the numbers of properties at risk under future climate scenarios based on detailed hydrological and hydraulic modelling.
• Identify the criticality and vulnerability of key public infrastructure (electricity, gas, water supply, sewage works, telecommunications, transport, schools) and produce regulations for their protection from flooding.  (The Summer 2007 floods demonstrated how flooding to critical infrastructure can have much wider reaching impacts than the localised flooding itself).

(Many organisations rely critically on constant power supply.  The risks need to be considered cross-organisationally to identify key interdependencies.  Systems are only as strong as the weakest link and this may lie with another organisation or operator.)

• Ensure the continuing protection of important industries with specific defences and bunding to reduce the local flood risk.
• Relocate key industries/businesses and critical/vulnerable properties away from potential flood risk, particularly where it is inappropriate or unsustainable to provide defences.
• Provide improved regulation and guidance across all sectors for consideration of the impacts of flooding due to climate change.  Many regulators are not currently engaged in the debate on climate change, and its inclusion in their requirements and guidance, i.e. OFWAT, Rail Regulator, Housing Corporation. 
• Continue the tight control of developments allowable within the flood plain.
• Raise public awareness to the risk of flooding from all sources.  By increasing public awareness, the consequences of flooding may be reduced by encouraging different organisations and individuals to take appropriate steps to reduce the impacts of flooding. 
• Promote the flood warning service and encourage all properties at risk to register on Floodline Warnings Direct to ensure that they receive alerts in times of potential flooding.  (More than 205,000 properties, 70% of those at risk, are currently covered by the Environment Agency’s flood warning service, although not all of these are registered to receive warnings).
• Improvements to flood warning systems, specifically in fast reacting catchments.
• Production of multi-agency response plans, to co-ordinate responses during extreme events.  Effectively manage problems related to the potential isolation during flooding of emergency response co-ordination and rest centres are overcome to ensure delivery.
• Improve response units and equipment, and ensure clear access routes are kept available.  (In the North East, the fire service at Ashington has three high volume pumps [three times faster than conventional fire service pumps].  These were recently used in response to major regional flood events such as around Hull in summer 2007, and Carlisle in 2005).
• Promote the implementation of voluntary Flood Wardens to assist local responses during times of flooding.  This will help to reduce the risk to life and property through heightened community awareness and more rapid and effective response during flooding.
• Determine priorities for the protection of properties and assets in the event of flooding: priority to the protection of critical infrastructure and key access routes; followed by vulnerable populations; followed by flooding to residential housing.
• Establish partnership approaches and cross-sectoral responses to reduce potential flooding, for example the storage of water in uplands areas to fight potential fires caused by higher summer temperatures.
• Look for more innovative sustainable flood management approaches rather then traditional flood defences, such as allowing managed realignment areas and the upstream storage of flood water.
• Provide temporary or demountable flood defences available to low impact areas frequently affected by flooding. (In September 2008 demountable defences were successfully used to prevent flooding to an area in York.)  However, it is important to ensure access routes are always available for their installation.
• Increase maintenance of rivers for removal of vegetation and blockages to retain flow capacity, where this is economically justified.
• Ongoing public campaigns to reduce fly tipping and clear rubbish from rivers to reduce flood impacts during flash summer events and increased winter rainfall.
• Work in partnership to promote the improvement of flood resilience and flood proofing of ‘at risk’ buildings and provide individual property owners and businesses with useful information and advice.
• Make the most of opportunities for retrofitting flood proofing/resilience during the refurbishments of old housing stock, such as raised electrics and raised sub-floors (for post-event draining). 
• For new developments move away from lowest cost to most adaptable and sustainable developments, with the inclusion of sufficient resilience as necessary for the location.
• Develop new roads and railway sections at raised levels (on stilts/viaducts) in flood prone areas.  Consider such improvements and new bypasses for main routes already affected.
• Improve the future planning management of caravan and camping parks with increased tourism.  Low volume sites are not currently subject to planning permission due to their temporary nature.  Sites are often placed near watercourses/sea and are highly vulnerable to flooding impacts.
• Use changes in local land management in rural areas to reduce rates of surface runoff, such as the provision of hedgerows and ditches, and the lateral ploughing of fields along contours to reduce field runoff and the wash off of sediments, and retain nutrients on the fields.  (The current Forestry Commission study in Pickering and other Natural England Higher Level Stewardship schemes are currently looking into these and other aspects).

Surface water/Drainage
New drainage schemes and improvements typically incorporate some consideration for climate changes based on current best practice guidance.  Existing systems, however, are generally managed in a more reactive sense, although drainage area plans produced by the water companies should highlight areas most likely to be at risk.  The key action that could be taken would be to assess all systems likely to affect large numbers of people based on local climate changes, rather than general guidance values, to determine future areas at risk. 

For drainage systems:

• Determine a clear co-ordinating framework between local government, water companies, Highways Agency and Environment Agency for managing the flood risk from surface water drainage.
• All parties (Local Authorities, Water Companies, Environment Agency) to work in partnership to develop Integrated Urban Drainage (IUD) studies and Surface Water Management Plans (SWMP) to appropriately consider the combined risks of flooding from surface water and other sources.  These should incorporate the implications of climate change and identify management plans for the future maintenance of infrastructure.
• Implement flood warning systems specifically for surface water flooding.
• Ensure current design standards are appropriate, and locally relevant, to accommodate future increases in rainfall/runoff.  (Current planning requirements for new sewer design are outdated.  Designs often use old rainfall data and are required to a 1 in 30-year standard.  Yorkshire Water often include additional capacity within new sewers in known flood areas to accommodate for future climate changes).
• Strategically plan and implement system improvements across the network, although increased pipe sizes across the entire would clearly be impractical and investment would be better focussed on areas at greatest risk. 
• Include additional capacity for new build developments and into the existing system through network improvements to accommodate for predicted increases in rainfall.   
• Limit downstream impacts from new drainage systems by designing with over-sized pipe diameters and manholes to deliver a maximum appropriate outfall discharge, such as equivalent to normal greenfield runoff.  (This is currently often applied in areas of known flooding).
• Promote and increase investment into the wider application of source control techniques to attenuate flow volumes earlier in the system and reduce downstream impacts on existing ageing sewer networks.  This would also have the added benefit of reducing peak flood flows in problem watercourses.  (There are ongoing questions over the practicability of these methods, due to ownership issues and planning policy guidance requiring increasing numbers of houses with less available space between, which need to be resolved).
• Investigate opportunities for the management of combined flooding from different sources, such as the recent Defra Integrated Urban Drainage pilot schemes.  (Current nearby schemes in Bradford and West Garforth, Leeds, are to examine a range of approaches to develop more integrated urban drainage management strategies and closer collaboration between the different agencies.)
• Incorporate the retrofitting of SUDS (Sustainable Urban Drainage Systems) for an overall reduction of urban runoff.  Although, opportunities to retro-fit existing infrastructure may be limited and difficult, i.e. costly, to achieve. 
• Consider the retrofitting of balancing tanks into historic drainage systems in known flood areas to accommodate excess flows when sewers reach capacity.
• Provide households across residential areas with water butts for rainwater harvesting to counteract the effects of development creep, i.e. gardens being paved over. 
• Undertake public education for the importance of SUDS, source control of flooding, the community benefits of water butts, and the wider impacts of paving over garden areas.
• Ensure sufficient flood-proofing of infrastructure and equipment at sewage treatment works and pumping stations to accommodate greater flows.
• Flood-proof remote vulnerable properties where improvements would be costly. 
• Undertake improvements at CSOs in key environmentally sensitive locations where increased spills will have detrimental effects.
• Improve outfall capacity, storage provision or include pumping at CSOs most likely to be affected by climate changes (sea level rise or raised flood depths).  The design of fluvial flood defences should ensure to consider the impacts of raised water levels on adjacent CSOs.

 

top

Flooding from rivers and the sea
Flooding from the rivers and streams is generally pro-actively managed by the appropriate authorities as part of well-established flood risk management programmes.  These include flood warning systems, long-term and strategic planning, and the development and maintenance of appropriate flood risk management solutions.  Typically, these activities inherently consider the likely effects of future climate changes and are planned to continue into the future as part of central government’s approach to flood risk management.  Of particular note, the Environment Agency are currently progressing a scheme to raise the defences through Leeds city centre and provide additional upstream storage.  Work is estimated to cost in the region of £80 million and is expected to start in 2011.

Further detail on the adaptation responses that are proposed by the Environment Agency for the West Yorkshire area over the next (nominally) 100 years are presented in the local Catchment Flood Management Plan (CFMP) documents that have been produced by the Environment Agency: the Calder CFMP, Aire CFMP, and the Yorkshire Ouse CFMP.  These documents are soon to be finalised and will be publicly available.

In particular, the following adaptation measures should continue to be incorporated in this strategic approach; however individual Local Authorities should look to develop their own adaptation and flood response plans in relation to all aspects of flooding to be more specific to their own requirements.

• Continue monitoring and flood warning for fluvial flood events, particularly in upstream areas due to specific issues and the nature of flooding. 
• Incorporate more detailed assessments of the numbers of properties at risk under future climate scenarios based on detailed hydrological and hydraulic modelling.
• Identify the criticality and vulnerability of key public infrastructure (electricity, gas, water supply, sewage works, telecommunications, transport, schools) and produce regulations for their protection from flooding.  (The Summer 2007 floods demonstrated how flooding to critical infrastructure can have much wider reaching impacts than the localised flooding itself).

(Many organisations rely critically on constant power supply.  The risks need to be considered cross-organisationally to identify key interdependencies.  Systems are only as strong as the weakest link and this may lie with another organisation or operator.)

• Ensure the continuing protection of important industries with specific defences and bunding to reduce the local flood risk.
• Relocate key industries/businesses and critical/vulnerable properties away from potential flood risk, particularly where it is inappropriate or unsustainable to provide defences.
• Provide improved regulation and guidance across all sectors for consideration of the impacts of flooding due to climate change.  Many regulators are not currently engaged in the debate on climate change, and its inclusion in their requirements and guidance, i.e. OFWAT, Rail Regulator, Housing Corporation. 
• Continue the tight control of developments allowable within the flood plain.
• Raise public awareness to the risk of flooding from all sources.  By increasing public awareness, the consequences of flooding may be reduced by encouraging different organisations and individuals to take appropriate steps to reduce the impacts of flooding. 
• Promote the flood warning service and encourage all properties at risk to register on Floodline Warnings Direct to ensure that they receive alerts in times of potential flooding.  (More than 205,000 properties, 70% of those at risk, are currently covered by the Environment Agency’s flood warning service, although not all of these are registered to receive warnings).
• Improvements to flood warning systems, specifically in fast reacting catchments.
• Production of multi-agency response plans, to co-ordinate responses during extreme events.  Effectively manage problems related to the potential isolation during flooding of emergency response co-ordination and rest centres are overcome to ensure delivery.
• Improve response units and equipment, and ensure clear access routes are kept available.  (In the North East, the fire service at Ashington has three high volume pumps [three times faster than conventional fire service pumps].  These were recently used in response to major regional flood events such as around Hull in summer 2007, and Carlisle in 2005).
• Promote the implementation of voluntary Flood Wardens to assist local responses during times of flooding.  This will help to reduce the risk to life and property through heightened community awareness and more rapid and effective response during flooding.
• Determine priorities for the protection of properties and assets in the event of flooding: priority to the protection of critical infrastructure and key access routes; followed by vulnerable populations; followed by flooding to residential housing.
• Establish partnership approaches and cross-sectoral responses to reduce potential flooding, for example the storage of water in uplands areas to fight potential fires caused by higher summer temperatures.
• Look for more innovative sustainable flood management approaches rather then traditional flood defences, such as allowing managed realignment areas and the upstream storage of flood water.
• Provide temporary or demountable flood defences available to low impact areas frequently affected by flooding. (In September 2008 demountable defences were successfully used to prevent flooding to an area in York.)  However, it is important to ensure access routes are always available for their installation.
• Increase maintenance of rivers for removal of vegetation and blockages to retain flow capacity, where this is economically justified.
• Ongoing public campaigns to reduce fly tipping and clear rubbish from rivers to reduce flood impacts during flash summer events and increased winter rainfall.
• Work in partnership to promote the improvement of flood resilience and flood proofing of ‘at risk’ buildings and provide individual property owners and businesses with useful information and advice.
• Make the most of opportunities for retrofitting flood proofing/resilience during the refurbishments of old housing stock, such as raised electrics and raised sub-floors (for post-event draining). 
• For new developments move away from lowest cost to most adaptable and sustainable developments, with the inclusion of sufficient resilience as necessary for the location.
• Develop new roads and railway sections at raised levels (on stilts/viaducts) in flood prone areas.  Consider such improvements and new bypasses for main routes already affected.
• Use changes in local land management in rural areas to reduce rates of surface runoff, such as the provision of hedgerows and ditches, and the lateral ploughing of fields along contours to reduce field runoff and the wash off of sediments, and retain nutrients on the fields.  (The current Forestry Commission study in Pickering and other Natural England Higher Level Stewardship schemes are currently looking into these and other aspects).

Surface water/Drainage
New drainage schemes and improvements typically incorporate some consideration for climate changes based on current best practice guidance.  Existing systems, however, are generally managed in a more reactive sense, although drainage area plans produced by the water companies should highlight areas most likely to be at risk.  The key action that could be taken would be to assess all systems likely to affect large numbers of people based on local climate changes, rather than general guidance values, to determine future areas at risk. 

For drainage systems:

• Determine a clear co-ordinating framework between local government, water companies, Highways Agency and Environment Agency for managing the flood risk from surface water drainage.
• All parties (Local Authorities, Water Companies, Environment Agency) to work in partnership to develop Integrated Urban Drainage (IUD) studies and Surface Water Management Plans (SWMP) to appropriately consider the combined risks of flooding from surface water and other sources.  These should incorporate the implications of climate change and identify management plans for the future maintenance of infrastructure.
• Implement flood warning systems specifically for surface water flooding.
• Ensure current design standards are appropriate, and locally relevant, to accommodate future increases in rainfall/runoff.  (Current planning requirements for new sewer design are outdated.  Designs often use old rainfall data and are required to a 1 in 30-year standard.  Yorkshire Water often include additional capacity within new sewers in known flood areas to accommodate for future climate changes).
• Strategically plan and implement system improvements across the network, although increased pipe sizes across the entire would clearly be impractical and investment would be better focussed on areas at greatest risk. 
• Include additional capacity for new build developments and into the existing system through network improvements to accommodate for predicted increases in rainfall.   
• Limit downstream impacts from new drainage systems by designing with over-sized pipe diameters and manholes to deliver a maximum appropriate outfall discharge, such as equivalent to normal greenfield runoff.  (This is currently often applied in areas of known flooding).
• Promote and increase investment into the wider application of source control techniques to attenuate flow volumes earlier in the system and reduce downstream impacts on existing ageing sewer networks.  This would also have the added benefit of reducing peak flood flows in problem watercourses.  (There are ongoing questions over the practicability of these methods, due to ownership issues and planning policy guidance requiring increasing numbers of houses with less available space between, which need to be resolved).
• Investigate opportunities for the management of combined flooding from different sources, such as the recent Defra Integrated Urban Drainage pilot schemes.  (Current schemes in Bradford and West Garforth, Leeds, are to examine a range of approaches to develop more integrated urban drainage management strategies and closer collaboration between the different agencies.)
• Incorporate the retrofitting of SUDS (Sustainable Urban Drainage Systems) for an overall reduction of urban runoff.  Although, opportunities to retro-fit existing infrastructure may be limited and difficult, i.e. costly, to achieve. 
• Consider the retrofitting of balancing tanks into historic drainage systems in known flood areas to accommodate excess flows when sewers reach capacity.
• Provide households across residential areas with water butts for rainwater harvesting to counteract the effects of development creep, i.e. gardens being paved over. 
• Undertake public education for the importance of SUDS, source control of flooding, the community benefits of water butts, and the wider impacts of paving over garden areas.
• Ensure sufficient flood-proofing of infrastructure and equipment at sewage treatment works and pumping stations to accommodate greater flows.
• Flood-proof remote vulnerable properties where improvements would be costly. 
• Undertake improvements at CSOs in key environmentally sensitive locations where increased spills will have detrimental effects.
• Improve outfall capacity, storage provision or include pumping at CSOs most likely to be affected by climate changes (raised river flood depths).  The design of fluvial flood defences should ensure to consider the impacts of raised water levels on adjacent CSOs.

 

top

Flooding from rivers and the sea
Flooding from the rivers, streams and sea is generally pro-actively managed by the appropriate authorities as part of well-established flood risk management programmes.  These include flood warning systems, long-term and strategic planning, and the development and maintenance of appropriate flood risk management solutions.  Typically, these activities inherently consider the likely effects of future climate changes and are planned to continue into the future as part of central government’s approach to flood risk management.  Presently flood storage sites are being considered on the lower Ouse and Trent to allow flooding during high tides to reduce river levels elsewhere.

Further detail on the adaptation responses that are proposed by the Environment Agency for the Humber area over the next (nominally) 100 years are presented in the local Catchment Flood Management Plan documents that have been produced by the Environment Agency: the Derwent CFMP, Hull and Coastal Streams CFMP, and lower sections of the Trent CFMP, the Ancholme CFMP, and Lough Coastal Streams CFMP.  These documents are soon to be finalised and will be publicly available.

In addition the Environment Agency’s Humber Flood Risk Management Strategy document proposes adaptation management measures to cope with climate change increases in tidal levels into the future. It is likely to prove difficult to maintain the long lengths of fluvial defences along the estuary against rising sea levels into the future.  The Environment Agency is therefore proposing to not maintain some of the defences to allow certain areas to flood.  This creation of managed realignment areas also provides additional wetland creation which offsets the biodiversity loss due to coastal squeeze in the estuary with the rising sea levels.  The Environment Agency is currently identifying suitable coastal sites for managed realignment of the embankments to provide 1,000 hectares of additional inter-tidal habitat around the Humber.  With Government approval for £323million investment over the next 25 years, work has already been completed including flood storage schemes at Alkborough and Thorngumbald and defence improvements at Saltmarshe, Goole and north of Keadby.  Projects are also progressing at other locations including realignment schemes at Donna Nook, Skeffling and opposite Goole and further defence improvements at Kingston-upon-Hull, Brough, Halton Marshes, Swinefleet and North Killlingholme.

Along the coastline and the mouth of the Humber Estuary the Humber Estuary Shoreline Management Plan also considers the future effects of climate change and proposes management strategies.  The plan is currently being prepared and further information is available at: ‘www.hecag-smp2.co.uk’.

In particular, the following adaptation measures should continue to be incorporated in this strategic approach; however individual Local Authorities should look to develop their own adaptation and flood response plans in relation to all aspects of flooding to be more specific to their own requirements.

• Continue monitoring and flood warning for river and tidal events, particularly in upstream areas due to specific issues and the nature of flooding. 
• Incorporate more detailed assessments of the numbers of properties at risk under future climate scenarios based on detailed hydrological and hydraulic modelling.
• Identify the criticality and vulnerability of key public infrastructure (electricity, gas, water supply, sewage works, telecommunications, transport, schools) and produce regulations for their protection from flooding.  (The Summer 2007 floods demonstrated how flooding to critical infrastructure can have much wider reaching impacts than the localised flooding itsel

(Many organisations rely critically on constant power supply.  The risks need to be considered cross-organisationally to identify key interdependencies.  Systems are only as strong as the weakest link and this may lie with another organisation or operator.)

• Ensure the continuing protection of important industries with specific defences and bunding to reduce the local flood risk.
• Relocate key industries/businesses and critical/vulnerable properties away from potential flood risk, particularly where it is inappropriate or unsustainable to provide defences.
• Provide improved regulation and guidance across all sectors for consideration of the impacts of flooding due to climate change.  Many regulators are not currently engaged in the debate on climate change, and its inclusion in their requirements and guidance, i.e. OFWAT, Rail Regulator, Housing Corporation. 
• Continue the tight control of developments allowable within the flood plain.
• Raise public awareness to the risk of flooding from all sources.  By increasing public awareness, the consequences of flooding may be reduced by encouraging different organisations and individuals to take appropriate steps to reduce the impacts of flooding. 
• Promote the flood warning service and encourage all properties at risk to register on Floodline Warnings Direct to ensure that they receive alerts in times of potential flooding.  (More than 205,000 properties, 70% of those at risk, are currently covered by the Environment Agency’s flood warning service, although not all of these are registered to receive warnings).
• Improvements to flood warning systems, specifically in fast reacting catchments.
• Production of multi-agency response plans, to co-ordinate responses during extreme events.  Effectively manage problems related to the potential isolation during flooding of emergency response co-ordination and rest centres are overcome to ensure delivery.
• Improve response units and equipment, and ensure clear access routes are kept available.  (In the North East, the fire service at Ashington has three high volume pumps [three times faster than conventional fire service pumps].  These were recently used in response to major regional flood events such as around Kingston-upon-Hull in Summer 2007, and Carlisle in 2005).
• Promote the implementation of voluntary Flood Wardens to assist local responses during times of flooding.  This will help to reduce the risk to life and property through heightened community awareness and more rapid and effective response during flooding.
• Determine priorities for the protection of properties and assets in the event of flooding: priority to the protection of critical infrastructure and key access routes; followed by vulnerable populations; followed by flooding to residential housing.
• Establish partnership approaches and cross-sectoral responses to reduce potential flooding.
• Look for more innovative sustainable flood management approaches rather then traditional flood defences, such as allowing managed realignment areas and the upstream storage of flood water. 
• Consider the areas protected and effectiveness of current defences to allow effort and funding to be concentrated in areas that will provide most benefit, and allowing more rural areas to flood in a controlled way.
• Provide temporary or demountable flood defences available to low impact areas frequently affected by flooding. (In September 2008 demountable defences were successfully used to prevent flooding to an area in York.)  However, it is important to ensure access routes are always available for their installation.
• Increase maintenance of rivers for removal of vegetation and blockages to retain flow capacity, where this is economically justified.
• Ongoing public campaigns to reduce fly tipping and clear rubbish from rivers to reduce flood impacts during flash summer events and increased winter rainfall.
• Work in partnership to promote the improvement of flood resilience and flood proofing of ‘at risk’ buildings and provide individual property owners and businesses with useful information and advice.
• Make the most of opportunities for retrofitting flood proofing/resilience during the refurbishments of old housing stock, such as raised electrics and raised sub-floors (for post-event draining). 
• For new developments move away from lowest cost to most adaptable and sustainable developments, with the inclusion of sufficient resilience as necessary for the location.
• Develop new roads and railway sections at raised levels (on stilts/viaducts) in flood prone areas.  Consider such improvements and new bypasses for main routes already affected.
• Improve the future planning management of caravan and camping parks with increased tourism.  Low volume sites are not currently subject to planning permission due to their temporary nature.  Sites are often placed near watercourses/sea and are highly vulnerable to flooding impacts.
• Use changes in local land management in rural areas to reduce rates of surface runoff, such as the provision of hedgerows and ditches, and the lateral ploughing of fields along contours to reduce field runoff and the wash off of sediments, and retain nutrients on the fields.  (The current Forestry Commission study in Pickering and other Natural England Higher Level Stewardship schemes are currently looking into these and other aspects).

Surface water/Drainage
New drainage schemes and improvements typically incorporate some consideration for climate changes based on current best practice guidance.  Existing systems, however, are generally managed in a more reactive sense, although drainage area plans produced by the water companies should highlight areas most likely to be at risk.  The key action that could be taken would be to assess all systems likely to affect large numbers of people based on local climate changes, rather than general guidance values, to determine future areas at risk. 

For drainage systems:

• Determine a clear co-ordinating framework between local government, water companies, Highways Agency and Environment Agency for managing the flood risk from surface water drainage.
• All parties (Local Authorities, Water Companies, Environment Agency) to work in partnership to develop Integrated Urban Drainage (IUD) studies and Surface Water Management Plans (SWMP) to appropriately consider the combined risks of flooding from surface water and other sources.  These should incorporate the implications of climate change and identify management plans for the future maintenance of infrastructure.
• Implement flood warning systems specifically for surface water flooding.
• Ensure current design standards are appropriate, and locally relevant, to accommodate future increases in rainfall/runoff.  (Current planning requirements for new sewer design are outdated.  Designs often use old rainfall data and are required to a 1 in 30-year standard.  Yorkshire Water often include additional capacity within new sewers in known flood areas to accommodate for future climate changes).
• Strategically plan and implement system improvements across the network, although increased pipe sizes across the entire would clearly be impractical and investment would be better focussed on areas at greatest risk. 
• Increase pumping and storage provision (or reduce incoming flows) to balance against the increased effects of tide-locking of sewer system outfalls.
• Include additional capacity for new build developments and into the existing system through network improvements to accommodate for predicted increases in rainfall.   
• Limit downstream impacts from new drainage systems by designing with over-sized pipe diameters and manholes to deliver a maximum appropriate outfall discharge, such as equivalent to normal greenfield runoff.  (This is currently often applied in areas of known flooding).
• Promote and increase investment into the wider application of source control techniques to attenuate flow volumes earlier in the system and reduce downstream impacts on existing ageing sewer networks.  This would also have the added benefit of reducing peak flood flows in problem watercourses.  (There are ongoing questions over the practicability of these methods, due to ownership issues and planning policy guidance requiring increasing numbers of houses with less available space between, which need to be resolved).
• Investigate opportunities for the management of combined flooding from different sources, such as the recent Defra Integrated Urban Drainage pilot schemes.  (Current nearby schemes in Bradford and West Garforth, Leeds, are to examine a range of approaches to develop more integrated urban drainage management strategies and closer collaboration between the different agencies.)
• Incorporate the retrofitting of SUDS (Sustainable Urban Drainage Systems) for an overall reduction of urban runoff.  Although, opportunities to retro-fit existing infrastructure may be limited and difficult, i.e. costly, to achieve. 
• Consider the retrofitting of balancing tanks into historic drainage systems in known flood areas to accommodate excess flows when sewers reach capacity.
• Provide households across residential areas with water butts for rainwater harvesting to counteract the effects of development creep, i.e. gardens being paved over. 
• Undertake public education for the importance of SUDS, source control of flooding, the community benefits of water butts, and the wider impacts of paving over garden areas.
• Ensure sufficient flood-proofing of infrastructure and equipment at sewage treatment works and pumping stations to accommodate greater flows.
• Flood-proof remote vulnerable properties where improvements would be costly. 
• Undertake improvements at CSOs in key environmentally sensitive locations where increased spills will have detrimental effects.
• Improve outfall capacity, storage provision or include pumping at CSOs most likely to be affected by climate changes (sea level rise or raised flood depths).  The design of fluvial flood defences should ensure to consider the impacts of raised water levels on adjacent CSOs.

 

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Flooding from rivers and the sea
Flooding from the rivers and streams is generally pro-actively managed by the appropriate authorities as part of well-established flood risk management programmes.  These include flood warning systems, long-term and strategic planning, and the development and maintenance of appropriate flood risk management solutions.  Typically, these activities inherently consider the likely effects of future climate changes and are planned to continue into the future as part of central government’s approach to flood risk management.

Further detail on the adaptation responses that are proposed by the Environment Agency for the South Yorkshire area over the next (nominally) 100 years are presented in the local Catchment Flood Management Plan document that has been produced by the Environment Agency: the Don and Rother CFMP.  This document is soon to be finalised and will be publicly available.

In particular, the following adaptation measures should continue to be incorporated in this strategic approach; however individual Local Authorities should look to develop their own adaptation and flood response plans in relation to all aspects of flooding to be more specific to their own requirements.

• Continue monitoring and flood warning for river and tidal events, particularly in upstream areas due to specific issues and the nature of flooding. 
• Incorporate more detailed assessments of the numbers of properties at risk under future climate scenarios based on detailed hydrological and hydraulic modelling.
• Identify the criticality and vulnerability of key public infrastructure (electricity, gas, water supply, sewage works, telecommunications, transport, schools) and produce regulations for their protection from flooding.  (The Summer 2007 floods demonstrated how flooding to critical infrastructure can have much wider reaching impacts than the localised flooding itself).

(Many organisations rely critically on constant power supply.  The risks need to be considered cross-organisationally to identify key interdependencies.  Systems are only as strong as the weakest link and this may lie with another organisation or operator.)

• Ensure the continuing protection of important industries with specific defences and bunding to reduce the local flood risk.
• Relocate key industries/businesses and critical/vulnerable properties away from potential flood risk, particularly where it is inappropriate or unsustainable to provide defences.
• Provide improved regulation and guidance across all sectors for consideration of the impacts of flooding due to climate change.  Many regulators are not currently engaged in the debate on climate change, and its inclusion in their requirements and guidance, i.e. OFWAT, Rail Regulator, Housing Corporation. 
• Continue the tight control of developments allowable within the flood plain.
• Raise public awareness to the risk of flooding from all sources.  By increasing public awareness, the consequences of flooding may be reduced by encouraging different organisations and individuals to take appropriate steps to reduce the impacts of flooding. 
• Promote the flood warning service and encourage all properties at risk to register on Floodline Warnings Direct to ensure that they receive alerts in times of potential flooding.  (More than 205,000 properties, 70% of those at risk, are currently covered by the Environment Agency’s flood warning service, although not all of these are registered to receive warnings).
• Improvements to flood warning systems, specifically in fast reacting catchments.
• Production of multi-agency response plans, to co-ordinate responses during extreme events.  Effectively manage problems related to the potential isolation during flooding of emergency response co-ordination and rest centres are overcome to ensure delivery.
• Improve response units and equipment, and ensure clear access routes are kept available.  (In the North East, the fire service at Ashington has three high volume pumps [three times faster than conventional fire service pumps].  These were recently used in response to major regional flood events such as around Hull in summer 2007, and Carlisle in 2005).
• Promote the implementation of voluntary Flood Wardens to assist local responses during times of flooding.  This will help to reduce the risk to life and property through heightened community awareness and more rapid and effective response during flooding.
• Determine priorities for the protection of properties and assets in the event of flooding: priority to the protection of critical infrastructure and key access routes; followed by vulnerable populations; followed by flooding to residential housing.
• Establish partnership approaches and cross-sectoral responses to reduce potential flooding, for example the storage of water in uplands areas to fight potential fires caused by higher summer temperatures.
• Look for more innovative sustainable flood management approaches rather then traditional flood defences, such as allowing managed realignment areas and the upstream storage of flood water.
• Provide temporary or demountable flood defences available to low impact areas frequently affected by flooding. (In September 2008 demountable defences were successfully used to prevent flooding to an area in York.)  However, it is important to ensure access routes are always available for their installation.
• Increase maintenance of rivers for removal of vegetation and blockages to retain flow capacity, where this is economically justified.
• Ongoing public campaigns to reduce fly tipping and clear rubbish from rivers to reduce flood impacts during flash summer events and increased winter rainfall.
• Work in partnership to promote the improvement of flood resilience and flood proofing of ‘at risk’ buildings and provide individual property owners and businesses with useful information and advice.
• Make the most of opportunities for retrofitting flood proofing/resilience during the refurbishments of old housing stock, such as raised electrics and raised sub-floors (for post-event draining). 
• For new developments move away from lowest cost to most adaptable and sustainable developments, with the inclusion of sufficient resilience as necessary for the location.
• Develop new roads and railway sections at raised levels (on stilts/viaducts) in flood prone areas.  Consider such improvements and new bypasses for main routes already affected.
• Use changes in local land management in rural areas to reduce rates of surface runoff, such as the provision of hedgerows and ditches, and the lateral ploughing of fields along contours to reduce field runoff and the wash off of sediments, and retain nutrients on the fields.  (The current Forestry Commission study in Pickering and other Natural England Higher Level Stewardship schemes are currently looking into these and other aspects).

Surface water/Drainage
New drainage schemes and improvements typically incorporate some consideration for climate changes based on current best practice guidance.  Existing systems, however, are generally managed in a more reactive sense, although drainage area plans produced by the water companies should highlight areas most likely to be at risk.  The key action that could be taken would be to assess all systems likely to affect large numbers of people based on local climate changes, rather than general guidance values, to determine future areas at risk. 

For drainage systems:

• Determine a clear co-ordinating framework between local government, water companies, Highways Agency and Environment Agency for managing the flood risk from surface water drainage.
• All parties (Local Authorities, Water Companies, Environment Agency) to work in partnership to develop Integrated Urban Drainage (IUD) studies and Surface Water Management Plans (SWMP) to appropriately consider the combined risks of flooding from surface water and other sources.  These should incorporate the implications of climate change and identify management plans for the future maintenance of infrastructure.
• Implement flood warning systems specifically for surface water flooding.
• Ensure current design standards are appropriate, and locally relevant, to accommodate future increases in rainfall/runoff.  (Current planning requirements for new sewer design are outdated.  Designs often use old rainfall data and are required to a 1 in 30-year standard.  Yorkshire Water often include additional capacity within new sewers in known flood areas to accommodate for future climate changes).
• Strategically plan and implement system improvements across the network, although increased pipe sizes across the entire would clearly be impractical and investment would be better focussed on areas at greatest risk. 
• Include additional capacity for new build developments and into the existing system through network improvements to accommodate for predicted increases in rainfall.   
• Limit downstream impacts from new drainage systems by designing with over-sized pipe diameters and manholes to deliver a maximum appropriate outfall discharge, such as equivalent to normal greenfield runoff.  (This is currently often applied in areas of known flooding).
• Promote and increase investment into the wider application of source control techniques to attenuate flow volumes earlier in the system and reduce downstream impacts on existing ageing sewer networks.  This would also have the added benefit of reducing peak flood flows in problem watercourses.  (There are ongoing questions over the practicability of these methods, due to ownership issues and planning policy guidance requiring increasing numbers of houses with less available space between, which need to be resolved).
• Investigate opportunities for the management of combined flooding from different sources, such as the recent Defra Integrated Urban Drainage pilot schemes.  (Current nearby schemes in Bradford and West Garforth, Leeds, are to examine a range of approaches to develop more integrated urban drainage management strategies and closer collaboration between the different agencies.)
• Incorporate the retrofitting of SUDS (Sustainable Urban Drainage Systems) for an overall reduction of urban runoff.  Although, opportunities to retro-fit existing infrastructure may be limited and difficult, i.e. costly, to achieve. 
• Consider the retrofitting of balancing tanks into historic drainage systems in known flood areas to accommodate excess flows when sewers reach capacity.
• Provide households across residential areas with water butts for rainwater harvesting to counteract the effects of development creep, i.e. gardens being paved over. 
• Undertake public education for the importance of SUDS, source control of flooding, the community benefits of water butts, and the wider impacts of paving over garden areas.
• Ensure sufficient flood-proofing of infrastructure and equipment at sewage treatment works and pumping stations to accommodate greater flows.
• Flood-proof remote vulnerable properties where improvements would be costly. 
• Undertake improvements at CSOs in key environmentally sensitive locations where increased spills will have detrimental effects.
• Improve outfall capacity, storage provision or include pumping at CSOs most likely to be affected by climate changes (raised river flood depths).  The design of fluvial flood defences should ensure to consider the impacts of raised water levels on adjacent CSOs.

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