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Here you will learn about the impacts expected from climate change by the 2050s on flooding across the region. This includes assessments of:
Over recent years there have been an increasing number of extreme rainfall and flooding events that seem to occur on a more frequent basis. Within the North East region major recent river flooding in areas, such as Hexham in January 2005, as well as numerous surface water and sewer flooding problems, such as that caused by the intense rainfall that hit South Shields, Washington and Newcastle in June 2005, show the likely consequences of flooding within the region and how important it is to tackle problems before the situation worsens. Outside of the region, there have been several major flooding events in recent years. In January 2005 approximately 2,000 properties (including the police station and council offices) were flooded across Carlisle and surrounding areas when heavy rainfall over an extended period caused the River Eden to break its banks and overtop flood defences. This caused in excess of £250m of damage to local properties and the fatality of two elderly residents, as well as leaving 40,000 properties without power. Then in summer 2007 the worst flooding seen in decades hit areas around York and Humberside, as well as the Midlands, Gloucestershire and South East. Flooding affected an even greater number of properties (about five times as many) than had been flooded during the previous major events that had occurred during the autumn of 2000, when serious flooding struck similar areas. Flooding claimed the lives of several people, over 55,000 homes and businesses were flooded across England and Wales, totalling an approximate £3 billion in insured losses alone, and key critical utilities were affected. Water supplies to 140,000 homes in Gloucestershire were cut off for up to two weeks, and almost 300 schools in Yorkshire and Humberside suffered damage. May to July 2007 was the wettest period since records began in 1766. The ground became saturated during May and early June followed by several periods of extreme rainfall, with some locations experiencing up to a month’s rainfall falling in a few hours. This led to widespread flooding across England and Wales. Intense rainfall produced some of the highest river levels on record and extensive flooding from the rivers Don, Severn and Thames, as well as widespread surface water flooding, notably around York and Humberside. Two-thirds of the properties were flooded due to the overwhelming of drains or sewers by the heavy, intense rainfall. In specific incidents, on 15 June 2007 dozens of houses and business were flooded throughout North Yorkshire, in Harrogate, Catterick Garrison, Colburn and Bedale, and had to be pumped out, five schools were flooded, in Filey, Burnestone (near Bedde), Coppice Valley (near Harrowgate) and Hackness (near Scarborough), the A1 at Catterick was closed in both directions, East Coast Main Line trains were significantly delayed, and a 1km section of the C77 road in Weardale was washed away by high flood flows. On 20/21 July 2007, flooding wreaked havoc to several villages across Teesdale and North Yorkshire. Near Scotch Corner flash floods resulted in waist-deep water gushing through the centre of villages resulting in flooded homes, demolished walls and torn up tarmac in Gilling West, Melsonby, The Green, Oswin Grove and High Street. The extensive flooding events of summer 2007 also showed the importance and criticality of key utility infrastructure, as water treatment works and electricity sub-stations were impacted which then affected significantly greater numbers of the surrounding population. As well as residents, many organisations rely heavily on constant power and water supply to support the local population, which highlights the criticality of these services to the wider community than that directly affected by flooding. The Government instigated a review into the summer 2007 floods. The Pitt Review reports observations on the extents and impacts of the flooding, and makes recommendations for the regulation and organisation of flood risk management, the management of surface water flooding and drainage, emergency response to extreme events and the identification and protection of critical infrastructure. The Environment Agency also produced a Review of 2007 Summer Floods which also makes further recommendations for improvements. Looking to future flooding impacts associated with a changing climate, conclusions from the Office of Science and Technology’s Foresight Flood and Coastal Defence report estimate that at a national level the risk of flooding from rivers and the sea will at least double by the 2080s, and could increase by up to 20 times. The number of people at a high risk of flooding in the UK could rise from 1.5 million to between 2.3 and 3.5 million over this period, with the cost of flooding rising from the current £1 billion a year to between £1.5 billion and £21 billion. This clearly represents a significant threat to the lives of many communities and the way the country operates as a whole. Following sections assess how flooding may affect the region by the 2050s, based on the projected climate changes.
The north east region covers an area of approximately 8,700 km2. The region is characterised by high upland and steep, fast-flowing streams in the Cheviots and Pennines in the west, gentler valley slopes and wider natural floodplains in the central areas, falling towards a rugged coastline where the land meets the North Sea in the east. The general landfall in the area is from west to east. Land uses across the region vary from undeveloped rural areas and agricultural land in extensive fell and moorland areas, to forested hillsides, to heavily urbanised and developed areas within major city centres. The significant rivers in the region, from south to north, are the River Tees, River Wear, River Derwent, River Tyne, River Wansbeck, River Coquet and River Tweed. There are numerous smaller tributaries to these main rivers across the region and several other coastal streams which discharge directly into the North Sea. The main conurbations in the region are the cities of Newcastle, Sunderland, Durham, Middlesbrough, and the main towns of Darlington, Hartlepool, Stockton-on-Tees, Alnwick and Berwick-upon-Tweed. Within the region, previous major flooding has occurred along the length of the River Tyne, particularly around Hexham, Corbridge and Haltwhistle, along the River Wear between Crook and Chester-le-Street, on the River Tees from Darlington to the Tees Estuary and on the River Till around Wooler. Coastal flooding has occurred at Blyth and Hartlepool and along the Berwick-upon-Tweed coastline.
Impacts A recent paper from Newcastle University concluded that recent trends in the UK are consistent with the climate projections which suggest an increase in the frequency and intensity of heavy rainfall. It showed that there has been a change in the timing of extreme rainfall with the majority now occurring during the autumn months. The paper also determined that the magnitude of recent extreme rainfall events has increased two-fold over parts of the UK since the 1960s, and that intensities previously experienced every 25 years now occur at approximately 6 year intervals. The various mechanisms and sources of flooding across the North East will be vulnerable to the following effects of climate change. Flooding from rivers and the sea
Flood defences
Surface water/Drainage Historically, urban sewer systems have been designed to carry the combined flows of household waste and rainwater. For the last 30 years, however, drainage systems have generally been constructed to carry these flows separately, although combined drainage systems are still common in older areas, some dating back to Victorian times. This legacy means that the vast majority of the existing sewer network in the urban locations will comprise predominantly combined sewer systems. Foul sewers become overloaded during large rainfall events leading to the flooding of properties and roads. Blockages within the system due to general debris are also prevalent and can exacerbate problems or lead to additional flooding. More extensive, and higher risk, flooding problems are typically related to river or tidal flooding, although, as the events of summer 2007 have shown, localised flooding from foul and surface water sewers or directly from surface water runoff can be equally as devastating and often more numerous. Surface water flooding events typically occur with a fairly high frequency, but are generally of relatively low impact. Flooding incidents are commonly isolated and highly localised problems, and although prevalent and recurrent in many areas, particularly affect steeper upland areas and steep urbanised areas. In addition, direct flooding from surface water runoff can occur where drainage provision is insufficient or non-existent, when rainfall directly runs off from the surrounding ground and does not issue from a watercourse and is not able to enter a local drainage system (often referred to as unconnected flooding). Surface runoff can be a significant cause of flooding, especially across urban areas and the steeper upland areas. Foul and surface water drainage systems potentially are vulnerable to the following effects of climate change:
As the previous recent major events have shown (York in 2000, Carlisle in 2005, York, Hull, Humberside, etc in summer 2007) the impacts of flooding to the population and country’s assets can be severe. The major impacts to the community are:
From our discussions with various organisations within the region, one of greatest threats posed by the weather on social wellbeing in the region was determined to be the serious potential for disruption to transport networks, as we have experienced with previous events. Also, the likelihood for vulnerable people and communities left without electricity, heating or water due to the flooding of critical infrastructure (as occurred during the summer 2007 floods). With regards to our flood defences, the maintenance of watercourses and the management of flood risk across the region, key impacts will include:
| Northumberland | Tyne & Wear | County Durham | Tees Valley |
The sub-region of Northumberland covers an area of approximately 5,078km2. The main towns in the sub-region include Rothbury, Alnwick, Berwick-upon-Tweed, Wooler, Blyth, Cramlington, Seaton Delaval, Morpeth, Ponteland, Hexham, Corbridge, Ashington, Bedlington and Newbiggin-by-the-Sea.
The main rivers within the region are the River Aln, River Coquet, River Blyth, River Tyne, River Tweed and River Wansbeck.
The current Environment Agency Flood Zones indicate the areas within the Northumberland sub-region that are potentially at risk of flooding from rivers or the sea. Significant potential flooding is shown along much of the River Tyne and its main tributaries. Most extensive is the potential flooding along the Tyne valley affecting areas around Hexham, and downstream past Corbridge and towards Prudhoe and Wylam. Upstream of Hexham there is significant potential flooding shown along the South Tyne, affecting areas from Haltwhistle through to Haydon Bridge. Also on the River North Tyne there is significant potential flooding shown along much of its length, particularly affecting areas between Lanehead and Bellingham. In addition, there is potential flooding shown on the River Rede around Otterburn.
Significant potential flooding is shown in the River Till catchment, notably at its confluence with the River Glen to the north of Wooler. Potential flooding is also shown upstream along the Glen back as far as Westnewton. Most of the potential flooding here will only affect rural areas, although towns and properties may be affected in Fenton, Doddington, Euart Newtown, Coupland, and Lanton, as well as Wooler. Potential flooding is also shown along much of the length of the River Breamish, affecting places such as Powburn, Brandon, East Lilburn and Chatton.
Potential flooding into the district from the southern banks of the Tweed is also apparent. This affects much of the length of the Tweed, and those towns situated close to it, such as Wark, Cornhil-on-Tweed, Norham, Horncliffe and of course Berwick itself. Significant potential flooding is shown along the River Pont around Stamfordham and Fenwick, as well as around Ponteland. On the River Wansbeck there is significant potential flooding shown in Morpeth, as well as further upstream towards Middleton, although most of this potential flooding only affects rural areas. On the River Blyth there is some significant potential flooding shown, but again only affecting rural areas. Most of the potential flooding from rivers in Northumberland will only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. Potential tidal flooding is an issue along significant lengths of the Northumberland Coast. These are notably along the lower coastal stretches of the sub-region. The predicted tidal flooding at Budle Bay, near Holy Island, are extensive and stretch from Warren Mill and Easington up to Haggerston and Goswick in the north. There is also significant coastal flooding at the mouths of the River Aln at Alnmouth and River Coquet at Warkworth. Potential significant tidal flooding is also indicated at Beadnell Bay, Druridge Bay, Newbiggin and Blyth.
Tidal flooding at the lower end of many of the coastal streams along the Northumberland coastline also affects several locations. In the south of the region, East Sleekburn and Blyth are significantly affected, with the Port and Power Station within the indicative extents of potential tidal flooding. Newbiggin and Cambois are also at risk.
Previous reports of significant flooding events within Northumberland include: Tynedale, 19/20 July 2007 – Heavy torrential rain and flash floods across Tynedale, affecting properties in Haydon Bridge, Bardon Mill, Hexham, Henshaw and Haltwhistle. Belford, 3 July 2007 - Flooding from the main watercourse due to insufficient channel capacity. Haltwhistle/Greenhead June 2007 – Elderly residents evacuated from homes as flooding up to 8 inches when drainage system unable to cope with heavy rainfall. Greenhead drains unable to cope, flooding village. Hexham Races were abandoned. Hexham/Tynedale, January 2005 – Extensive flooding from River South Tyne and River Tyne. Water main in Hexham burst, leaving 10,000 households without water for several days. The same event affected many areas around the River Wear.
Wooler, 13 August 2004 – flooding from the main river due to the channel capacity being exceeded. The same event also affected extensive areas of Tynedale. Ponteland, 6 November 2000 - Flooding from main river due to exceeded channel capacity led to extensive flooding along A696.
River South Tyne, River Tyne, 31 January 1995 - Extensive flooding along the river. Ponteland, 15 January 1978 - Extensive flooding from main river from Berwick Hill to Prestwick. Hexham/ Corbridge, January 1955 – overtopping of river defences led to extensive flooding along the River Tyne. Blyth – Major tidal flooding has previously occurred. Due to the low-lying, basin-shaped topography, the town is particularly at risk of flooding from the sea. Northumberland contains around 135 km of flood banks, 5.5 km of flood walls and 2 km of other defences with 22 other raised defences. There are few river flood defences provided within rural areas of Northumberland due to the small number of people at risk. In Alnwick there are defences provided around Rothbury and Holystone on the Coquet, and near High Newton.There are significant river flood defences across the Berwick-upon-Tweed district. These are mostly provided along the Rivers Till and Glen to the north and west of Wooler. There are further defences upstream on the River Breamish around East Lilburn, Wooperton and Old Bewick. There are several stretches of river flood defences across Castle Morpeth. There are significant flood defences in Ponteland and Morpeth providing protection to these towns from river flooding. In addition there are extensive lengths of flood defence embankments downstream of Ponteland through predominantly rural areas. There are several river flood defences provided within Tynedale, notably along the River Tyne around Hexham and Corbridge, and intermittent sections on the River North Tyne from Falstone down to Bellingham, with further sections downstream near Wark and Park End. There are some short sections of defences on the River South Tyne around Haydon Bridge and Haltwhistle, and defences along the River Rede around Rochester, Horsley and Otterburn. There are defence embankments provided along some of the coastal streams protecting areas of historic flooding, at Haggerston, Goswick and Cheswick, and towards Elwick. Foul and separate surface water drainage systems are spread extensively across Northumberland and will be typically small contained systems serving each of the local communities. The specific individual drainage systems across the sub-region are numerous. Typically, foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. In these rural areas the foul/combined systems will be inter-linked, possibly via pumping, between small villages to a single local treatment works. There are 174 sewage treatment works and 198 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, many of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage, from within a village or group of properties and discharge directly into local watercourses or the sea. In more constrained historic urban areas, surface water systems may often be linked to discharge into the foul/combined system. There is significant risk of flooding from surface water sources within the various urban centres across the sub-region, particularly in Ponteland, where significant previous flooding has occurred.
Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk across the sub-region:
Our discussions with various organisations within the sub-region highlighted the risk to caravan parks and camping sites. Several caravan parks are known to be at risk of flooding from rivers or coastal erosion. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed by the Environment Agency as having a medium level of flood vulnerability. The Environment Agency also has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. The table below shows the vulnerable populations across the Northumberland sub-region:
Regarding transport networks, the following sections of the road and rail system within Northumberland are likely to be affected by flooding:
There are several fords across watercourses within the upland rural areas and these can become significantly dangerous to cross when river levels are high following heavy rainfall. This poses a serious hazard on smaller watercourses in the upland areas that might not be accounted for here.
Flooding incident records for the sewer and drainage systems within Northumberland indicate the following locations to be at risk of flooding from the sewer system:
In addition, it is known that in the order of 120 properties in Ponteland were affected by a combination of watercourse and localised surface water flooding in November 2000. Approximately 50 of these are thought to have flooded due to surface water problems. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of current problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore only limited information is available. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded, especially in rural areas. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across Northumberland. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms, with a greater increase shown with the more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the sub-region. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in the upland areas of the district will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground, particularly in upland areas. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys in the upland areas are likely to be most susceptible. These upland areas already experience higher levels of rainfall, and more severe storms, throughout the year. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
The Tyne & Wear sub-region covers an area of approximately 550 km2. Tyne & Wear contains the major conurbations of Newcastle upon Tyne, Gateshead and Sunderland. The main rivers in the sub-region are the River Tyne and River Wear.
The River Tyne forms the boundary between Newcastle upon Tyne and North Tyneside to the north, and Gateshead and South Tyneside to the south. This is a considerably sized river, having joined flows from the Rivers North and South Tyne together off the Cheviots and the North Pennines, and discharges significant flow volumes during periods of heavy rainfall. The Tyne discharges into the North Sea at Tynemouth and is tidally affected throughout the sub-region.
The River Wear cuts through Sunderland district, passing Washington to the south before flowing through the centre of Sunderland city to its discharge into the North Sea. The Wear discharges significant flow volumes during periods of heavy rainfall and is tidally affected along its full length through the sub-region.
Other significant rivers in Tyne & Wear include the River Derwent, River Team and River Don. The current Environment Agency Flood Zones indicate the areas within Tyne & Wear that are potentially at risk of flooding from rivers or the sea. The flood zones show significant potential flooding in Tyne & Wear occurs at the River Tyne and the lower end of the River Derwent, at its confluence. The main areas affected are around Ryton, Blaydon and the Metro Centre. There is also more extreme potential flooding shown from the River Team as it passes through Gateshead and at its confluence with the Tyne. Most of the potential flooding is likely to affect open fields and flood plain areas around Ryton, although properties situated at a low level near the rivers are likely to be affected. There is extensive potential flooding near Ponteland from the River Pont, although it is not thought that this affects any properties. North and South Tyneside show minimal potential flooding from the Tyne, although certain small areas near Willington and North Shields show some potential flooding. Some potential flooding is also shown around Longbenton, associated with potential flooding from the Ouseburn affecting discharges from the local tributary. The confluence of the River Don with the Tyne at Jarrow also shows limited potential flooding. Along the Wear there is minimal potential flooding shown within the sub-region, except for some minor potential flooding in the centre of Sunderland and around Fatfield. The key potential flooding in urban areas is likely to be associated with bridges and culverted sections of the watercourse where flows become constrained and is likely to impact on roads and local properties. Flood zones in coastal areas of Tyne & Wear indicate that the rugged coastline generally provides good defence to the adjacent towns against potential tidal flooding. Newcastle, May/June 2005 – areas of Heaton, Walker Fawdon and Cradlewell suffered extensive flooding during extreme rainfall events. Water gushed into houses in Woodlands Park, North Gosforth due to inadequate drainage. Flooding in Benton and High Heaton due to a lack of drainage gullies and gulley blockages. South Shields, June 2005 – numerous road closures after flash flooding. Water and debris flooded homes, pubs and businesses. South Shields, Summer 2004 – roads closed as drains were unable to cope with heavy rainfall. Gateshead, April 2004 – flash flooding on roads led to closures. There are around 3 km of formal river flood defences under Environment Agency responsibility such as embankments within Tyne & Wear. More than 1.5 km of these defences are found in the Sunderland area, on minor watercourses near Castletown and around Fence Houses. Flood defences are located on the Ouseburn at Longbenton, around West Boldon and Hebburn and Whickham and on the Derwent to the west of Whickham near Chopwell. Quay walls along the River Tyne provide limited flood protection to local areas such as the Fish Quays at North Shields, South Shields and the NewcastleGateshead Quayside, although there has been previous know tidal overtopping of these structures. These quay walls are under the responsibility of the local authorities. Coastal defences are provided along the coastline at North Tyneside and parts of South Tyneside to protect against tidal flooding and erosion. Foul and separate surface water drainage systems are spread extensively across the urban areas within the district with various interconnected systems discharging to treatment works and into local watercourses. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems will be inter-linked, possibly via pumping, to a single local treatment works. There are 32 sewage treatment works and 170 sewage pumping stations within the sub-region. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, some of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system. There are significant risks of urbanised flooding from surface water sources within the sub-region, where the large areas of impermeable surfaces produce significant volumes of runoff following intense rainfall events that overwhelm the local drainage systems. Significant previous flooding has been reported in areas of Newcastle Gateshead, Jarrow, South Shields and Whitley Bay. There is no mapping currently available of potential areas at risk, however the data that is available is discussed in the following, Impacts, section.
Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk across the sub-region:
The residential impacts to the local population have been determined. Residential properties are classed by the Environment Agency as having a medium level of flood vulnerability. The Environment Agency also has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. The table below shows the vulnerable populations at risk across the Tyne & Wear sub-region:
Regarding transport networks, following sections of the road and rail system within the Tyne & Wear sub-region are likely to be affected by flooding:
Flooding incident records for the sewer and drainage systems within the Tyne & Wear sub-region indicate the following locations to be at risk of flooding from the sewer system:
These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of current problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore only limited information is available. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded, especially in rural areas. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across Tyne & Wear. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms, with a greater increase shown with the more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. The projected increase in extreme rainfall events is likely to lead to increased flooding within the sub-region. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows;
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
The sub-region of Durham covers an area of approximately 2233 km2. The main urban centres in the sub-region include Durham, Chester-le-Street, Consett, Bishop Auckland, Newton Aycliffe, Stanhope, Seaham, and Peterlee.
The main rivers in the Durham sub-region are the River Wear, River Tees, River Browney and River Skerne. The River Wear has its source around Cornriggs and Burnhope Reservoir and flows through the steep Weardale valley through Wearhead, Stanhope and Wolsingham, and on past Bishop Auckland and onwards through Durham and Chester-le-Street.
The Wear is a considerably sized river through Durham City and Chester-le-Street and discharges significant flow volumes during periods of heavy rainfall. There are several watercourses across the Wear Valley that cascade from the surrounding moors to form tributaries to the Wear, joining at various points along its length.
The main river through the Derwentside district is the River Browney. This collects flows from the Pennines around Consett and Waskerley and flows easterly, through Lanchester, and then on through the district to join the Wear to the south of Durham. The other main river is the River Derwent which passes on the west side of Consett and forms the north-western boundary of the district.
The main dominant river within Teesdale is the River Tees. This has its source around Cow Green Reservoir and cascades through the steep Cauldron Snout and High Force waterfalls and flows through Middleton-in-Teesdale and Mickleton, then on through the centre of Barnard Castle and beyond towards Darlington and Middlesbrough. There are several other main watercourses across the Teesdale district that drop from the surrounding high peaks of the Pennines hills to form tributaries to the Tees, such as the Harwood Beck, the River Lune, and the River Greta. Also the River Gaunless has its source around Copley, in the north of the Teesdale district, and flows easterly through Butterknowle and Evenwood and onwards to its confluence with the River Wear near Bishop Auckland.
The main river through the Sedgefield district is the River Skerne, which collects flows from across the whole borough and flows south to join the Tees at Darlington. The river brings together various tributaries from the north-west, around Spennymoor and to the south of Chilton, from the west, through the centre of Newton Aycliffe, and the Hurworth Burn from the north-east, passing Fishburn and Sedgefield. There are various coastal streams in the Easington district which discharge directly into the North Sea. The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea Significant potential flooding is shown from the River Wear affecting areas to the east of Chester-Le-Street and open rural areas to the west of Great Lumley. Other significant potential flooding is shown around the lower end downstream of Stanhope, affecting areas around Witton-Le-Wear, Escomb, Bishop Auckland and Willington, as well as Wolsingham, Frosterley and Stanhope. There is limited flooding shown from most of the Wear tributaries, however there is significant potential flooding indicated from the Gaunless particularly affecting West Auckland as well as Bishop Auckland. There is limited potential flooding from the River Derwent, most notably upstream of Lanchester and to the south of South Moor, near Annfield Plain. Main potential flooding is likely to affect Burnopfield and the outskirts of Consett. The main significant potential flooding in the Sedgefield district is shown from the River Skerne, mainly affecting a large rural area to the east of the A1(M), near Mordon, and extending northwards as well as Bradbury and southern areas of Newton Aycliffe. Additionally the tributary through Newton Aycliffe indicates potential flooding in the centre of the town. Significant potential flooding is shown along much of the length of the River Tees, particularly affecting areas around Mickleton and upstream of Middleton-in-Teesdale, as well as Barnard Castle and Winston at the downstream end. There is extensive flooding from one of the lower tributaries of the Tees affecting significant areas around Staindrop. Also there is flooding of Barningham Moor affecting Barningham in the south of the district, and from the River Gaunless affecting Evenwood. The key flooding affecting urban areas is likely to be associated with bridge crossings and culverted sections of the watercourse where flows become constrained, and is likely to impact on roads and local properties. Much of the flooding is likely to only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. With the high rugged cliffs there is little coastal flooding shown along the Easington coastline. The main location for potential tidal flooding is at Seaham. Much of the potential coastal flooding would only affect rural areas, as the towns are generally set back away from the cliffs, except at Seaham, which with the port is more low-lying to the coast.
Previous reports of significant flooding events within the Durham sub-region include:
Along the length of the Wear, there are flood defences near Great Lumley and significant flood embankments between Sunderland Bridge and Durham. Many of the flood defence embankments are situated through rural areas only, and are not protecting local towns or properties. There is also a short stretch of flood wall within Durham City. There are few formal river flood defences provided within Easington, with only approximately 250m of raised defences provided around the Hurworth Burn Reservoir. Significant river flood defences are provided within the Sedgefield district; with approximately 9.5km of formal raised defences on the River Skerne and main tributaries to the east of Newton Aycliffe and adjacent to the A1(M), as well as further north on the Skerne to the west of Sedgefield. In addition, there are 900m of culverted watercourse within the Sedgefield area. There are several formal river flood defences provided within Teesdale, with approximately 8km of flood embankments, 1.2km of flood walls and 450m of other defences provided around and upstream of Stanhope in the upper vallley, around Witton-Le-Wear and Escomb in the middle, and through rural areas downstream of Bishop Auckland. In addition there are significant flood defences provided on the River Gaunless at West Auckland and Bishop Auckland, including a recent £8.7 million flood alleviation scheme which includes flood walls through West Auckland and an upstream flood storage reservoir. The scheme was completed in 2004 and provides protection to more than 400 properties. There are few formal river flood defences provided within the district, with only a short stretch of raised defences on the River Derwent at Hamsterley, upstream of Burnopfield. The River Derwent has short lengths of raised defences at Hamsterley, upstream of Burnopfield and the River Deerness has some flood defences near New Brancepeth. Foul and separate surface water drainage systems are spread extensively across Durham and will be typically small contained systems serving each of the local communities. The specific individual drainage systems across the sub-region are numerous. Typically, foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. In these rural areas the foul/combined systems will be inter-linked, possibly via pumping, between small villages to a single local treatment works. There are 137 sewage treatment works and 135 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, many of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage, from within a village or group of properties and discharge directly into local watercourses or the sea. In more constrained historic urban areas, surface water systems may often be linked to discharge into the foul/combined system.
Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk across the sub-region:
Our discussions with various organisations within the sub-region highlighted the risk to caravan parks and camping sites. Several caravan parks are known to be at risk of flooding from rivers or coastal erosion. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed by the Environment Agency as having a medium level of flood vulnerability. The Environment Agency also has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. The table below shows the vulnerable populations across the Durham sub-region:
Regarding transport networks, the following sections of the road and rail system within Northumberland are likely to be affected by flooding:
There are several fords across watercourses within the upland rural areas and these can become significantly dangerous to cross when river levels are high following heavy rainfall. This poses a serious hazard on smaller watercourses in the upland areas that might not be accounted for here. Flooding incident records for the sewer and drainage systems within the Durham sub-region indicate the following locations to be at risk of flooding from the sewer system:
These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of current problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore only limited information is available. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded, especially in rural areas. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across Northumberland. Rainfall will become more seasonal however, and there is projected to be a general increase in winter and spring rainfall, up to 20% at the coast and up to approximately 10% in the higher upland areas. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms, with a greater increase shown with the more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the sub-region. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in the upland areas of the district will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground, particularly in upland areas. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys in the upland areas are likely to be most susceptible. These upland areas already experience higher levels of rainfall, and more severe storms, throughout the year. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
The Tees Valley sub-region covers an area of 814 km2. Significant urban areas within the sub-region include Darlington, Hartlepool, Middlesbrough, Billingham, Yarm and Saltburn-By-The-Sea.
The main river in the sub-region is the River Tees, which collects together various main rivers and becks off the Pennines through Teesdale and other minor tributaries throughout the sub-region, flowing easterly into the Tees Estuary.
Along the coast, some watercourses discharge directly into the sea, at locations such as Saltburn and Skinningrove. The coastal streams are particularly steep, fast-flowing watercourses which drop swiftly from the surrounding moors towards the North Sea. Other significant rivers in Tees Valley include the River Skerne, flowing through Darlington and into the Tees at Croft-on-Tees, Bishopton Beck flowing through Bishopton and Whitton to join the Tees at Stockton and the River Leven which has its confluence with the Tees downstream of Yarm. The Tees Barrage is situated on the east side of Stockton and controls the tidal limit of the Tees. The current Environment Agency Flood Zones indicate the areas within Tees Valley that are potentially at risk of flooding from rivers or the sea. Significant potential flooding is indicated from the River Tees affecting areas around Hurworth-on-Tees, Croft-on-Tees, Low Dinsdale, Neasham, Yarm, Aislaby, Eaglescliffe, Thornaby and Stockton. There is some potential flooding shown along the length of the River Skerne, affecting Barmpton, Coatham Mundeville and extreme potential flooding in the centre of Darlington, and on its tributary affecting westerly parts of Darlington and the town of Denton.
The key flooding in urban areas is likely to be associated with major road crossings at bridges and culverts where flows become constrained. Flooding in these areas is likely to impact on roads and local properties.
The predominant potential flooding in the east of the sub-region is caused by significant potential tidal flooding from the Tees Estuary which could result in extensive inundation across Teesport. Additional potential tidal flooding from the coast is shown to affect areas across Redcar and in Hartlepool, particularly around the centre and harbour area and at Seaton Carew. Rising water levels in the Tees Estuary cause backing up of tributary watercourses, producing flooding on smaller watercourses such as at Billingham and through Middlesbrough city centre. There are currently estimated to be 560 industries at risk of tidal flooding within the Tees Estuary area, representing about £½ billion in direct flood damages. The number of commercial properties likely to be affected rises to more than 900 properties with future sea level rise. There is also the potential for the outfalls from surface water drainage systems to become tide-locked, causing systems to back-up leading to increased flooding if significant rainfall events occur during high tides. Much of the flooding from rivers within western sections of the sub-region is likely to only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. Previous reports of significant flooding events within Tees Valley include: Darlington, June/July 2007 – heavy rainfall led to closure of Eastbourne and Branksome Secondary Schools and Cockerton CE Primary. Durham Tees Valley Airport terminal and restaurant flooded and powercuts were observed. Roads were closed due to overflowing drains. Seaton Carew, July 2007 – flooded 14 times since 2001, 4 times with raw sewage due to a mechanical fault at a pumping station during heavy rainfall. Hartlepool, August 2004 – homes in Owton Manor were flooded for the third time in two years due to overflowing sewers. Flooding occurred in homes, gardens and roads. Some sewage flooding occurred due to inadequate drainage system. A building in Toffs Farm Industrial Estate flooded. Skinningrove, November 2000 – 2 months of rainfall fell in 2 hours causing high floods from the beck. Floods were due to heavy rainfall combined with high tides and the steep nature of the surrounding valley.
River flood defences are provided along almost the full length of the Tees through Darlington, notably on the south side of Darlington, and around Piercebridge, Hurworth, Sockburn, Low Dinsdale and Neasham. There are also raised flood defences on the Skerne around Darlington. There are some river flood defences provided within the borough, with approximately 7.5km of raised flood defences provided near Greatham, on the Tees tributaries and as tidal defences along the Tees estuary in the south. There are 19 additional flood defence structures on watercourses within the borough and almost 1km of culverted watercourse, primarily through the central areas of Hartlepool. Hartlepool district contains raised flood defences near Greatham on the Tees tributaries and tidal defences along the Tees Estuary. There are almost 1km of culverted watercourse, primarily through the central areas of Hartlepool. Stockton-On-Tees contains extensive flood defences around Yarm, Aislaby, Eaglescliffe Thornaby, Stockton and Billingham with 21km of flood embankments and 200m of other defence structures. In addition, there is almost 300m of culverted watercourse through the urban areas. There are no formal river flood defences provided within the districts of Middlesbrough and Redcar and Cleveland; however formal maintenance operations are undertaken on around 40 km of the local watercourses, including the Tees. In addition, there are more than 250m of culverted watercourse across the city of Middlesbrough. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. In the larger towns systems will be larger and more interconnected. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems will be inter-linked, possibly via pumping between small villages, to a single local treatment works. There are 44 sewage treatment works and 171 sewage pumping stations within the Tees Valley sub-region. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, some of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system.
Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk across the sub-region:
Also the residential impacts to the local population have been determined. Residential properties are classed by the Environment Agency as having a medium level of flood vulnerability. The Environment Agency also has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. The table below shows the vulnerable populations across the Tees Valley sub-region:
Regarding transport networks across Tees Valley, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems within Tees Valley indicate the following locations to be at risk of flooding from the sewer system: Sewer flooding records:
To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across Tees Valley. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall In addition there is likely to be an increase in the intensity and magnitude of some individual rainfall events, particularly shorter duration storms, with a greater increase shown with the more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the sub-region. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. In addition, along with changes in rainfall patterns, climate change will cause significant sea level rise along the North East coastline. Mean sea levels are expected to rise by approximately 250mm by 2050, based on current guidance from Defra, and extreme sea surge levels are likely to be even more exaggerated. The main, significant flooding in coastal areas of Tees Valley is caused by tidal flooding. Future rises in extreme sea levels will lead to increased extents of flooding, affecting a greater number of properties than currently, and on a more frequent basis. Studies of the identification of the extents of future tidal flooding are ongoing through the current revision to the Shoreline Management Plan along the coastline. This will ascertain the specific areas which are likely to be affected by rising sea levels, and propose recommended management methods to cope with the flooding. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows;
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys in the upland areas are likely to be most susceptible. These upland areas already experience higher levels of rainfall, and more severe storms, throughout the year. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
For an overview of the impacts for your local area please click on the list/map below.
Description
The two main rivers within the district are the River Aln and the River Coquet. The River Coquet is the main dominant river catchment in the area. With its source in the uplands of the Cheviots it drops through the hillsides of Coquetdale around Rothbury and then out across the flatter lowlands to its discharge at Warkworth. The River Aln has its source in the lower Cheviots and then meanders easterly through the lower hills and past Alnwick to discharge at Alnmouth. Within the district there are also other minor tributaries to these main rivers, and coastal streams which discharge directly into the sea. The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea. Along the Coquet there is some flooding indicated along much of its length, particularly affecting areas around Rothbury, and upstream as far as Alwinton. There is also significant flooding indicated around Felton and Guyzance. Along the Aln, most of the flooding is indicated around Whittingham, Broome Park and Bolton, with some around Hulme Park and Alnwick, however flooding in these areas affects very few properties. Most of the flooding from both of these rivers will only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. Tidal flooding is possibly a greater issue, with significant flooding shown at the mouths of both of these rivers, affecting Warkworth and Amble on the Coquet and Alnmouth on the Aln, as well as further up the coast affecting Boulmer. There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are few river flood defences provided within the district, due to the rural nature of the area and the small number of population at risk; with approximately 700m of flood banks, 400m of flood walls and 70m of other defences provided around Rothbury and Holystone on the Coquet, and near High Newton. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. The specific individual drainage systems across the district are numerous. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. In these rural areas the foul/combined systems will be inter-linked, possibly via pumping, between small villages to a single local treatment works. There are 34 sewage treatment works and 38 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, many of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage from within a village or group of properties and discharge directly into local watercourses. Impacts The following table presents a summary of the key properties and assets currently identified to be at risk of flooding from rivers and the sea under the present day climate. These are shown under particular vulnerability sections based on the safety risks posed if there were flooding to this type of property. Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Our discussions with various organisations within the district highlighted the risk to caravan parks and camping sites. Several caravan parks are known to be at risk of flooding from rivers or coastal erosion. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed as medium vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Most of the areas affected are in the medium vulnerability class, although more vulnerable populations are affected by flooding around Rothbury, Alnmouth and Boulmer.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
There are several fords across watercourses within the rural areas and these can become significantly dangerous to cross when river levels are high following heavy rainfall. This poses a serious hazard on smaller watercourses in the upland areas that might not be accounted for here. Flooding incident records for the sewer and drainage systems indicate that there are 4 properties within the Alnwick district identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of current problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but in such rural areas anecdotal reports are not as readily available.To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms, with a greater increase shown with the more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in the upland areas of the district will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground, particularly in upland areas. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys in the upland areas are likely to be most susceptible. These upland areas already experience higher levels of rainfall, and more severe storms, throughout the year. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
Description
The main river catchment within the district is the River Till, with its tributaries the River Glen and River Breamish. The tributaries collect flows from the burns cascading down from the Cheviot Hills in the south of the borough before discharging into the River Till, which then meanders away from the coast, north-westerly, before discharging into the River Tweed. The Tweed brings flows from further westerly, from the Hills of the Scottish Borders, and from its confluence with the River Till continues to flow north-easterly to its discharge into the sea at Berwick-Upon-Tweed. To the east of the River Till, from Beadnell to Cheswick, coastal streams collect flows from small, local catchments to discharge directly into the sea.
The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea. Significant flooding is shown in the River Till catchment, notably at its confluence with the River Glen to the north of Wooler. Flooding is also shown upstream along the Glen back as far as Westnewton. Most of the flooding here will only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected, particularly in Fenton, Doddington, Euart Newtown, Coupland, and Lanton, as well as Wooler. Flooding is also shown along much of the length of the River Breamish, affecting places such as Powburn, Brandon, East Lilburn and Chatton. Flooding into the district from the southern banks of the Tweed is also apparent. This affects much of the length of the Tweed, and those towns situated close to it, such as Wark, Cornhil-on-Tweed, Norham, Horncliffe and of course Berwick itself. Much of the river flooding is produced by the fast flows coming down from the high upland hills and reaching the flatter lowland areas where river gradients are less steep, and river conveyance is reduced.
Tidal flooding is also a notable issue, particularly around Holy Island. The predicted tidal flooding areas are extensive stretching from Warren Mill and Easington up to Haggerston and Goswick in the north. Some tidal flooding is also shown around Seahouses and Beadnell in the south of the borough.
There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are significant river flood defences across the borough protecting areas at risk from flooding. There are approximately 83 km of flood banks. These are mostly provided along the Rivers Till and Glen to the north and west of Wooler, protecting the areas and towns mentioned highlighted previously. There are further defences upstream on the River Breamish around East Lilburn, Wooperton and Old Bewick. There are also some defence embankments provided along some of the coastal streams protecting areas of historic flooding, at Haggerston, Goswick and Cheswick, and towards Elwick. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. The specific individual drainage systems across the district are numerous. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. In these rural areas the foul/combined systems will be inter-linked, possibly via pumping, between small villages to a single local treatment works. There are 29 sewage treatment works and 31 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, many of the properties are likely to be unconnected to the foul drainage system and will have their own septic tanks. Surface water systems will typically collect surface water drainage from within a village or group of properties and discharge directly into local watercourses or into the sea. Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Our discussions with various organisations within the district highlighted the high risk posed to caravan parks and camping sites. There are six sites identified to be at risk of flooding from rivers or coastal erosion, and many other smaller, temporary sites likely to be within the high risk flood zone. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed as medium vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Most of the areas affected are in the medium vulnerability class, although more vulnerable populations are affected by the flooding around Wooler, Warren Mill, Cornhill-on-Tweed, Norham and Berwick.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
There are several fords across watercourses within the upland rural areas and these can become significantly dangerous to cross when river levels are high following heavy rainfall. This poses a serious hazard on smaller watercourses in the upland areas that might not be accounted for here.
Flooding incident records for the sewer and drainage systems indicate that there is only one location identified to be at risk of flooding from the sewer system within the borough, in Belford. Flooding incident records for the sewer and drainage systems indicate that there are 8 properties within the Berwick upon Tweed borough identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. The sewer flood records present properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but in such rural areas anecdotal reports are not as readily available. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the borough. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
In addition, along with changes in rainfall patterns, climate change will cause significant sea level rise along the North East coastline. Mean sea levels are expected to rise by approximately 250mm by 2050, based on current guidance from Defra, and extreme sea surge levels are likely to be even more exaggerated. Future rises in extreme sea levels is likely to lead to increased extents of flooding along the coastline, particularly around Holy Island and Budle Bay, affecting a wider area than currently and on a more frequent basis. Studies of the identification of the extents of future tidal flooding are ongoing through the current revision to the Shoreline Management Plan along the Northumberland coastline. This will ascertain the specific areas which are likely to be affected by rising sea levels, and propose recommended management methods to cope with the flooding. The Northumberland Shoreline Management Plan 2 is due for completion in December 2008. Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in the upland areas of the borough will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground, particularly in upland areas. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys in the upland areas are likely to be most susceptible. These upland areas already experience higher levels of rainfall, and more severe storms, throughout the year. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
Description
The Port of Blyth is situated adjacent to the coast on either side of the River Blyth. The main river is the River Blyth which forms the northern boundary of the borough with Wansbeck District. Other smaller watercourses, notably Maggie’s Burn and Seaton Burn, discharge near New Hartley and at Seaton Sluice respectively, with catchments extending into the centre of the borough towards Seaton Delaval and Cramlington. The current Environment Agency Flood Zones indicate the areas within the borough that are potentially at risk of flooding from rivers or the sea. The significant flooding is shown to be related to tidal flooding. At the lower end of the River Blyth, tidal flooding affects areas of the town. Additional tidal flooding at the coastal end of Maggie’s Burn affects the A193 and areas back towards New Hartley.
There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are few river flood defences provided within the borough with only two stretches of flood walls in Blyth totalling 52 in length. Foul and separate surface water drainage systems are spread extensively across the urban areas within the borough with various interconnected systems discharging to treatment works and into local watercourses. Foul sewer systems will comprise a network of drainage sewers, typically combining areas of separate and combined drainage in older urban areas, discharging to a sewage treatment works. There are 3 sewage treatment works and 22 sewage pumping stations within the borough. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses or the sea, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system. Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Also the residential impacts to the local population have been determined. Residential properties are classed as medium vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. The areas affected by flooding in Blyth are in a relatively high vulnerability class.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems indicate that there are 8 properties within the Blyth Valley borough identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood typically at low points where surrounding runoff flows are likely to drain to. Areas are particularly likely to be affected where surrounding areas are steep and have significant proportions of impermeable area creating large volumes of surface water runoff that will overwhelm the local drainage systems. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms, with greater increases shown with the more frequently occurring events. This is likely to produce more localised low impact flooding occurring on a more frequent basis. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With projected climate change increases in extreme sea levels and rainfall events, this is likely to produce increased tidal and river flooding within the borough. Based on estimates of climate change increases to flooding from rivers, the following additional assets have been identified to potentially be at risk in the future.
In addition, along with changes in rainfall patterns, climate change will cause significant sea level rise along the North East coastline. Mean sea levels are expected to rise by approximately 250mm by 2050, based on current guidance from Defra, and extreme sea surge levels are likely to even more exaggerated. The main, significant flooding to Blyth is caused by tidal flooding through the River Blyth estuary. Future rises in extreme sea levels will lead to increased extents of flooding, affecting a greater number of properties than currently, and on a more frequent basis. Studies of the identification of the extents of future tidal flooding are ongoing through the current revision to the Shoreline Management Plan along the Northumberland coastline. This will ascertain the specific areas which are likely to be affected by rising sea levels, and propose recommended management methods to cope with the flooding. The Northumberland Shoreline Management Plan 2 is due for completion in December 2008. There are currently re-development plans in place for certain areas occupied by the port and in the town centre. Future developments will have to ensure that they take flood risk, and the potential increases in future risk, into careful consideration so that future properties are not placed unnecessarily at risk. Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of high water levels similar to the extreme events experienced today, and the more frequent impacts that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as present day extremes and flood events become more frequent. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in steeper urban areas where there are significant extents of impermeable area are likely to be the most susceptible. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to come about are:
Description The main rivers within the district are the River Blyth and the River Wansbeck. The River Blyth flows from Bolam Lake in the centre of the catchment and meanders easterly across the district collecting the River Pont, which flows through Ponteland from areas to the south, before continuing east to discharge into the sea at Blyth. The River Wansbeck has its source in the foothills of the Cheviot Hills and cuts directly across the middle of the district, through the centre of Morpeth before passing through Wansbeck District to the east and discharging into the sea near Ashington. To the north of the district there are tributaries to the Wansbeck and also to the River Coquet to the north, as well as coastal streams which collect flows from small localised catchments and discharge directly into the sea, for example at Lynemouth. The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea. Significant flooding is shown along the River Pont around Stamfordham and Fenwick, as well as extensive at and around Ponteland. On the River Wansbeck there is significant flooding shown in Morpeth, as well as further upstream towards Middleton, although most of this flooding only affects rural areas. On the River Blyth there is some significant flooding shown, but again only affecting rural areas. Along the coast there is significant tidal flooding shown to open areas behind Druridge Bay. These do not appear to impact on any residential areas, although there may be some impacts from tidal flooding at Lynemouth and Cresswell to the south. There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are several stretches of river flood defences across the borough protecting areas most at risk from flooding. There are significant flood defences in Ponteland and Morpeth providing protection to these towns from river flooding, however only to approximately a 1 in 35-year event standard. In addition there are extensive lengths of flood defence embankments downstream of Ponteland through predominantly rural areas. In total across the district there are approximately 7.5 km of flood banks and 2 km of flood walls, along with 150m of other defences and 5 no. other raised defences. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities within the rural areas. The specific individual drainage systems across the district are numerous. More extensive and integrated networks will be distributed through the more urbanised towns of Morpeth, Lynemouth and Ponteland. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. Foul/combined systems will be inter-linked, possibly via pumping in more remote rural areas, and connected through to local treatment works. There are 35 sewage treatment works and 39 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In more remote rural areas, many of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses or the sea, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system. Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Our discussions with various organisations within the district highlighted certain key concerns. It is known that there are two key sewage treatment works at Morpeth that are located within flood plain, which raises concern over the potential for the contamination of flood water. There are also Police and Ambulance stations in Morpeth that are both located in the fluvial flood zone, and most roads into town are affected when River Wansbeck floods. This limits the response that can be provided to the town and other surrounding local areas during times of flooding, or if flooding coincides with other emergency requirements from these two sites. Several caravan parks across Northumberland sub-region at risk of flooding from rivers or coastal erosion. High vulnerable sites due to significant personal safety risks and risk of damage from cars caravans being carried by flood waters. Our discussions also highlighted the serious risk of flooding to caravan parks and camping sites. Several caravan parks including Golden Sands and Cresswell Towers in Castle Morpeth are believed to be at a significant risk of flooding from rivers or coastal erosion. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed as medium vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Most of the areas affected are in the medium vulnerability class, although more vulnerable populations affected by flooding are identified in Morpeth town.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems indicate that there are no properties within the Castle Morpeth district identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. In addition, it is known that in the order of 120 properties in Ponteland were affected by a combination of watercourse and localised surface water flooding in November 2000. Approximately 50 of these are thought to have flooded due to surface water problems. These records only represent properties that will be affected by typical storms up to 5% AEP however, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but often anecdotal reports are not as readily available. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter rainfall. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, with a greater increase shown with shorter duration, more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity storm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers and the sea, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
In addition, along with changes in rainfall patterns, climate change will cause significant sea level rise along the North East coastline. Mean sea levels are expected to rise by approximately 250mm by 2050, based on current guidance from Defra, and extreme sea surge levels are likely to be even more exaggerated. Future rises in extreme sea levels is likely to lead to increased extents of flooding along the coastline, particularly around Druridge Bay, affecting a wider area than currently and on a more frequent basis. Studies of the identification of the extents of future tidal flooding are ongoing through the current revision to the Shoreline Management Plan along the Northumberland coastline. This will ascertain the specific areas which are likely to be affected by rising sea levels, and propose recommended management methods to cope with the flooding. The Northumberland Shoreline Management Plan 2 is due for completion in December 2008. Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in the more upland areas of the district will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground, particularly in upland areas. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys in the upland areas are likely to be most susceptible. These upland areas already experience higher levels of rainfall, and more severe storms, throughout the year. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to arise are:
Description The main river through the district is the River Wear which meanders through the district from north to south. The Wear is a considerably sized river at this point and discharges significant flow volumes during periods of heavy rainfall. There are other minor watercourses spread across the district which collect local catchment flows and form tributaries to the Wear, including the Twizzell Burn, which flows through the centre of Chester-Le-Street, and the Lumley Park Burn, which joins the Wear from the west. The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea. Significant flooding is shown from the River Wear affecting areas to the east of Chester-Le-Street and open rural areas to the west of Great Lumley. Much of the flooding is likely to only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. The key flooding in urban areas is likely to be associated with major road crossings, such as at the A1/A183 and A182, at bridges and culverts where flows become constrained and is likely to impact on roads and local properties. There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are some river flood defences provided within the district, with approximately 4km of flood embankments and 620m of flood walls provided on the Wear, at the location of greatest flooding near Great Lumley, and on the Twizell Burn through Chester-Le-Street. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. In the larger towns systems will be larger and more interconnected. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems will be inter-linked, possibly via pumping, between towns to a single local treatment works. There are 6 sewage treatment works and 15 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, many of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses. Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Also the residential impacts to the local population have been determined. Residential properties are classed as medium risk vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Most of the areas affected are identified as being fairly highly vulnerable, although areas to the north of Chester-Le-Street are identified in the medium vulnerability class.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems indicate that there are 36 properties within the Chester-le-Street district identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Also low gradient urban areas are particularly likely to be affected where surrounding areas are steep and have significant proportions of impermeable area creating large volumes of surface water runoff that will overwhelm the local drainage systems. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter and spring rainfall, up to 20% in winter and approximately 7% in the spring. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity thunderstorm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in steeper areas of the district will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys are likely to be most susceptible, as well as steeper urban areas where there are significant extents of impermeable area. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the wetter winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to arise are:
Description
The main river in the area is the River Tees which forms the southern boundary to the borough. Having collected together various main rivers and becks off the Pennines through Teesdale, the Tees is a considerably sized river at this point and discharges significant flow volumes during periods of heavy rainfall. The other main river in the borough is the River Skerne. The source of the Skerne is at Hurworth Burn Reservoir in Sedgefield Borough, and the river enters the borough area from the north passing through the centre of Darlington to its confluence with the Tees at Croft-on-Tees. Another main river in the area is Bishopton Beck. This collects flows in the north-east corner of the borough around Bishopton and Whitton, and flows easterly to join the Tees at Stockton. There are also other minor tributaries across the district which all discharge into these main rivers or directly into the Tees. The current Environment Agency Flood Zones indicate the areas within the borough that are potentially at risk of flooding from rivers or the sea. Within the area there is considerable flooding shown from the Tees as it meanders past the borough, significantly affecting towns near the river, such as Hurworth-on-Tees, Croft-on-Tees, Low Dinsdale, Neasham, and the southern outskirts of Darlington. There is some flooding shown along the length of the Skerne, affecting Barmpton, Coatham Mundeville and extreme flooding in the centre of Darlington, and on its tributary affecting westerly parts of Darlington and the town of Denton. Much of the flooding from these rivers is likely to only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. The key flooding in urban areas is likely to be associated with major road crossings at bridges and culverts where flows become constrained and is likely to impact on roads and local properties.
There have been previous reports of flooding within the district as follows:
Regarding flooding from sewers, however, there are the following reported incidents:
There are significant river flood defences provided within the district, primarily along the Tees, although also on the Skerne and on the west side of Darlington. In total across the district there are approximately 22 km of raised flood defences. Defences are provided along almost the full length of the Tees past the borough, notably on the south side of Darlington, and around Piercebridge, Hurworth, Sockburn, Low Dinsdale and Neasham. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. In the larger towns systems will be larger and more interconnected. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems will be inter-linked, possibly via pumping between small villages, to a single local treatment works. There are 16 sewage treatment works and 29 sewage pumping stations within the borough. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, some of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system.
Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Our discussions with various organisations within the borough highlighted the risk to caravan parks and camping sites. There is a caravan park known to be at risk of flooding within the borough. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed as medium risk vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Most of the areas affected are in the medium vulnerability class, although more vulnerable populations are affected by flooding around Piercebridge, High Coniscliffe, Neasham and Low Dinsdale, and through the centre of Darlington.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems indicate that there are 14 properties within the Darlington borough identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Low gradient urban areas are particularly likely to be affected where surrounding areas are steep and have significant proportions of impermeable area creating large volumes of surface water runoff that will overwhelm the local drainage systems. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but in rural areas anecdotal reports are not as readily available. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events, particularly shorter duration storms, with a greater increase shown with the more frequently occurring events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity thunderstorm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Low gradient areas within and around the towns, particularly where there are significant extents of impermeable area, are likely to be the most susceptible, and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the wetter winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to arise are:
Description
The main river through the district is the River Browney. This collects flows from the Pennines around Consett and Waskerley and flows easterly, through Lanchester, and then on through the district to join the Wear to the south of Durham. The other main river is the River Derwent which passes on the west side of Consett and forms the north-western boundary of the district. There are other minor watercourses spread across the district which collect local catchment flows and form tributaries to these main rivers and the Wear. In the north, around Stanley and Burnopfield, these smaller watercourses flow northwards to join the River Derwent and the Tyne. The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers. These show that there is limited flooding within the district, most notably upstream of Lanchester and to the south of South Moor, near Annfield Plain. Main flooding is likely to be from the River Derwent affecting Burnopfield and the outskirts of Consett. Much of the flooding is likely to only affect rural areas, although properties situated at a low level near the rivers are likely to be affected. The key flooding is likely to be associated with major road crossings at bridges and culverts where flows become constrained and is likely to impact on roads and local properties. There have been previous reports of flooding within the district as follows:
There are few formal river flood defences provided within the district, with only a short stretch of raised defences on the River Derwent at Hamsterley, upstream of Burnopfield. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. In the larger towns systems will be larger and more interconnected. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems from several areas will be inter-linked, possibly via pumping, to a single local treatment works. There are 21 sewage treatment works and 18 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, many of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage from within a town or village and discharge directly into local watercourses. Impacts The following table presents a summary of the key properties and assets currently identified to be at risk of flooding from rivers under the present day climate. These are shown under particular vulnerability sections based on the safety risks posed if there were flooding to this type of property. Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Our discussions with various organisations within the district highlighted the significant risk to caravan parks and camping sites. There are several of these camping and caravan sites located within the district. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed as medium risk vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Most of the areas within the district are in the medium, or lower, vulnerability class, although more vulnerable populations are affected by flooding to the north of Consett, around Hamsterley and Ebchester, and in the centre of the district around Iveston, Annfield Plain and South Moor.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems indicate that there are 3 properties within the Derwentside district identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Also low gradient urban areas are particularly likely to be affected where surrounding areas are steep and have significant proportions of impermeable area creating large volumes of surface water runoff that will overwhelm the local drainage systems. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter and spring rainfall, up to 20% in winter and approximately 7% in the spring. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity thunderstorm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers, there are only a few additional assets that have been identified to potentially be at risk in the future, as follows.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. Locations in steeper areas of the district will be at a greater flood risk due to faster flood flows and the limited response time available from flood warnings. This is likely to increase with the increasing seasonality of rainfall bringing higher intensity, flashy flood flows, particularly during the summer months. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys are likely to be most susceptible, as well as steeper urban areas where there are significant extents of impermeable area. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the wetter winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to arise are:
Description
The main river through the district is the River Wear which meanders through the district from north to south. The Wear is a considerably sized river at this point and discharges significant flow volumes during periods of heavy rainfall. The other significant main river in the district is the River Browney which passes Langley Park and Bearpark and then flows south to join the River Wear downstream, to the north, of Sunderland Bridge. The River Deerness flows through Esh Winning and joins the River Browney before its confluence with the Wear. There are other minor watercourses spread across the district which collect local catchment flows and form tributaries to the Wear, including the Old Durham Beck, which joins the River Wear around Durham from the west.
The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea. The main significant flooding in the district is shown from the River Wear affecting areas such as Sunderland Bridge, Shincliffe and around Durham. Much of the flooding to the north and south of Durham is likely to only affect rural areas, although towns and properties situated at a low level near the rivers are likely to be affected. The key flooding in urban areas is likely to be associated with major road crossings, such as at the A177 and A167, at bridges and culverts where flows become constrained and is likely to impact on roads and local properties.
There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are significant river flood defences provided within the district, with more than 10km of flood embankments provided along the Wear between Sunderland Bridge and Durham. Many of the flood defence embankments are situated through rural areas only, and are not protecting local towns or properties. There is also a short stretch of flood walls within Durham of approximately 100m. A short length of flood embankment is also on the River Deerness near New Brancepeth. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. In the larger urban areas systems will be larger and more interconnected. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems will be inter-linked, possibly via pumping, to a single local treatment works. There are 24 sewage treatment works and 22 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system. Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
Our discussions with various organisations within the district highlighted the risk to caravan parks and camping sites. Several caravan parks are known to be at risk of flooding from rivers or coastal erosion. These are highly vulnerable sites due to the significant personal safety risks to people resident at the sites during times of flooding, and cars and caravans are particularly hazardous as they can be easily picked up and carried along by flood flows causing significant damage to other properties and risk to life. Also the residential impacts to the local population have been determined. Residential properties are classed as medium risk vulnerability. The Environment Agency has a social flood vulnerability index which identifies the vulnerability of populations based on age and social deprivation. Much of the district area is in the medium vulnerability class, although areas to the west of the River Wear, which are likely to be affected by flooding, and in the south-east around Kelloe and Quarrington Hill are identified as more vulnerable populations.
Regarding our transport networks, the following sections of the road and rail system are likely to be affected by flooding.
Flooding incident records for the sewer and drainage systems indicate that there are 49 properties within the Durham City district identified to be at risk of flooding from the sewer system on their ‘2 in 10-year’ and ‘1 in 10-year’ registers. These figures represent properties that will be affected by typical storms up to 5% AEP, and there are likely to be a significantly greater number of properties and areas affected by sewer and surface water flooding during higher intensity, more extreme storms, as we have seen with the flooding in summer 2007. The data on existing flood problems gives a good indication of the extent of recurrent problems related to the sewer system, however, in addition to the recorded/known incidents there will also be numerous other locations which are also likely to flood situated in outlying areas where properties are not affected and therefore limited information is not available. Also low gradient urban areas are particularly likely to be affected where surrounding areas are steep and have significant proportions of impermeable area creating large volumes of surface water runoff that will overwhelm the local drainage systems. Additional to those locations on the Northumbrian Water flood register, key highway and localised surface water flooding will readily occur, but can often be numerous and go unreported or unrecorded. To the 2050s, climate change is projected to cause a general reduction in the annual average rainfall across the district. Rainfall will become more seasonal however, and there is projected to be a general increase in winter and spring rainfall, up to 20% in winter and approximately 7% in the spring. In addition there is likely to be an increase in the intensity and magnitude of individual rainfall events. Despite a general reduction in summer rainfall, this effect is likely to produce more severe, high intensity thunderstorm events during the summer periods. With the projected increases in extreme rainfall events, this is likely to lead to increased flooding within the district. Based on estimates of climate change increases to flooding from rivers, the following additional properties have been identified to potentially be at risk in the future. The key critical assets and properties are shown in bold.
Of greater concern than the additional number of properties affected by future flood level increases, will be the increasing frequency of large rainfall events and the impact that this will have on the properties currently identified to be at risk. These assets will face an increasing risk of flooding as the present day extreme rainfall and flood events become more frequent. The increasing seasonality of rainfall and autumn and winter wetness, will lead to greater saturation of the ground. Greater saturation will cause a higher volume and rate of runoff flows, which will exacerbate the problems discussed above. This is likely to further increase the frequency and extent of problems and their impacts. Additional impacts of climate change on flooding and flood defences are also likely to become apparent, as follows.
With regard to sewer and surface water flooding, with increasing winter rainfall due to climate changes the occurrence of incidents at the known foul and surface water sewer flooding locations will become significantly more frequent during the winter months. Other problem locations will arise due to the increasing magnitude of events, but it is difficult to easily ascertain where these may occur. Fast flowing surface water runoff in the steep valleys are likely to be most susceptible, as well as steeper urban areas where there are significant extents of impermeable area. Also, low gradient areas within the main towns and low points on the road and rail networks will be vulnerable to increasing flooding, particularly where these are surrounded by steeper areas that will produce fast runoff flows from the projected more frequent and higher intensity storms. Northumbrian Water has noticed an increase in the frequency of high intensity summer storms that produce significant urban flooding over recent years, with significant flooding events having occurred in two of the last three years. Similarly to river flooding, the impacts of climate change will produce increases in the number and frequency of flooding events, particularly during the wetter winter period and during summer months due to high intensity thunderstorms. Other future impacts that are likely to arise are:
Description
There are various main rivers within the district, most of which are coastal streams which discharge directly into the sea at various locations: Seaham, Hawthorn, Easington, Peterlee and south of Blackhall Rocks. To the west an additional minor watercourse collects flows from around Haswell and South Hetton and flows westerly to form a tributary to the River Wear. Also, the Hurworth Burn collects flows from the southerly end of the district and flows south to join the River Skerne, which in turn then flows into the River Tees. The current Environment Agency Flood Zones indicate the areas within the district that are potentially at risk of flooding from rivers or the sea. These indicate that there is limited flooding from the main watercourses affecting the district. The key flooding in the district affects areas such as Hetton-Le-Hole, Seaham and Wheatley Hill. There is also some flooding shown around the reservoir on the Hurworth Burn in the south, although this only affects rural upland areas along this reach. The key flooding affecting the towns is likely to be associated with bridge crossings and culverted sections of the watercourse where flows become constrained, and is likely to impact on roads and local properties. With the high rugged cliffs there is little coastal flooding shown along the Easington coastline. The main location for tidal flooding is at Seaham. Much of the coastal flooding would only affect rural areas, as the towns are generally set back away from the cliffs, except at Seaham, which with the port is more low-lying to the coast.
There have been previous reports of flooding within the district as follows:
Also, regarding flooding from sewers:
There are few formal river flood defences provided within the district, with only approximately 250m of raised defences provided around the Hurworth Burn Reservoir. There are also 2.5km of maintained channel throughout the district. Foul and separate surface water drainage systems are spread extensively across the district and will be typically small contained systems serving each of the local communities. In the larger towns systems will be larger and more interconnected. Typically foul systems will comprise a network of drainage sewers, often combining areas of separate and combined drainage, leading to a sewage treatment works. The foul/combined systems will be inter-linked, possibly via pumping, to a single local treatment works. There are 4 sewage treatment works and 25 sewage pumping stations within the district. Various ancillary structures will be included through the system to assist network performance, primarily pumping stations, combined sewer overflows (CSOs), and storage tanks. CSOs provide an overflow release from the drainage system into local watercourses or surface water systems during times of high flows. In the rural areas, some of the properties are likely to be unconnected to the foul drainage system, and will have their own septic tanks. Surface water systems will typically collect surface water drainage separately from the foul sewerage. These typically discharge directly into local watercourses or the sea, although in more constrained historic urban areas may often be linked to discharge into the foul/combined system.
Impacts Notably, within the more extreme flood risk zone there are the following critical assets and properties at risk:
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