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Here you will learn about the impacts expected from climate change by the 2050s on groundwater and mine water. The Regional assessment covers large-scale processes, such as groundwater derived flooding from the Permian aquifer and saline intrusion, and also generic vulnerabilities and impacts. Further detail is provided in the Sub-regional assessments and, where available, specific information is contained within the Local Detail assessments. In so far as is possible, we have avoided undue repetition between the different scales of reporting.
Description Groundwater
There is relatively little concrete information on groundwater conditions in most of these strata, with the exception of the Permian aquifers (Younger 1995a) and the Lower Carboniferous Fell Sandstone in north Northumberland (Younger, 1998). The Permian aquifer is a major resource for domestic and industrial supply, which constitutes around 30% of the Sunderland supply and the entire supply of Hartlepool. The Fell Sandstone is an important resource for Berwick and rural Northumbrian settlements such as Rothbury and Wooler. The bulk of groundwater circulation in the region actually occurs in ‘man-made aquifers’ within the heavily mined Coal Measures strata. Mine Water
Vulnerability
Impacts The main regional-scale impacts associated with the projected climate changes by the 2050s are:
| Northumberland | Tyne & Wear | County Durham | Tees Valley |
Description
Major mine water discharges in Northumberland are associated with the Lower Carboniferous Coal Measures in the west of the region (principally along the South Tyne between Acomb and Lambley, but also in parts of north Northumberland), metal mine discharges from the North Pennines Lead-Zinc Orefield (principally into the River Allen and South Tyne catchments) and coal mine discharges form the extensive workings of the Upper Carboniferous Coal Measures in coastal Districts (e.g. from Blyth to Warkworth). Vulnerability
Impacts
Description
Extensive Coal Authority pumping operations in the area limit the extent of uncontrolled mine water discharges. There is a major treatment scheme at Lamesley in the Team Valley where pumped mine water from the former Kibblesworth Colliery is co-treated with sewage. Other coal mine discharges are clustered along the lower Derwent Valley (e.g. High Spen) and the banks of the Tyne (e.g. at Newburn, Blaydon, Ryton and Dunston). Vulnerability
Impacts
Description
Mine water discharges associated with former metal mining are abundant in upper Weardale and to a lesser extent Teesdale. Coal mine discharges are most important in central areas of the county (e.g. Lower Wear Valley around Bishop Auckland and east Derwentside). Pumping operations prevent uncontrolled discharges in coastal areas while rebound is still continuing in the lower Wear. Vulnerability
Impacts
Description
Mine water discharges in Tees Valley are associated with former ironstone mines at Skinningrove, Saltburn Gill, Eston and New Marske. Vulnerability The principal vulnerabilities are related to:
Impacts
For an overview of the impacts for your local area please click on the list/map below.
Description The main mine water discharge is associated with the former Whittle Colliery. This discharge is pumped into a passive treatment scheme by the UK Government’s Coal Authority. This pumping scheme commenced in 2002 and prevents outbreak of polluted coal mine water into the Hazon Burn and lower reaches of the River Coquet (a designated SSSI from source to mouth). Other mine water discharges are associated with spoil heap drainage at Shilbottle and at Chirm Mine near Forestburn Gate. Impacts The impact of mine water outbreak in the east of the district around the Whittle area is minimal given the continued Coal Authority pumping operations. At Shilbottle, the mine water discharge is related to spoil heap leaching and is low in volume and will not suffer the build-up and outbreak associated with mine discharges from underground workings. The Chirm mine is an example that has experienced some build up of groundwater head behind the discharge point and could be susceptible to future outbreak. Whether this outbreak will be prompted by the rapid increase in head associated with the multi-day rainfall events predicted to increase in frequency and intensity with climate change is uncertain. The remote location of the site on the Maglin Burn (a tributary of the lower Coquet) will make any outbreak unlikely to be of major impact.
Description The larger mine waters in the Berwick district are associated with coal mine drainage at Spittal on the coast just south of Berwick, and at Allerdean southwest of Berwick. The mines associated with these discharges all closed in excess of 40 years ago. Impacts It should also be recognised that the rising temperatures and drier summers are likely to increase tourism demand across the area, which in turn will place increased demand on the existing water supply, which is sourced from groundwater in the Berwick area. So at the times of greatest susceptibility, the demand will be further peaking due to both increased visitor numbers and the increased need for people to stay well hydrated during the warmer and intensely hot periods. In addition to domestic and agricultural supply, natural groundwaters are also locally important in the Berwick District in sustaining river baseflows (and salmonid spawning habitat) where there is a good hydraulic connection between surface and groundwaters (e.g. through Quaternary sands and gravels in the floodplains of the Breamish and Till). There are also isolated examples of groundwater-fed wetlands that may be susceptible to prolonged lowering of groundwater tables. The best example of such a wetland in Northumberland is found at Newham Fen National Nature Reserve (and Special Area of Conservation under the EU Habitats Directive) on the Northumberland coastal plain inland from Seahouses. The integrity of the wetland system has been shown to be associated with groundwater supply from a shallow Quaternary sand and gravel groundwater system in an esker ridge (Large et al., 2007). Rich fen wetland communities have been shown to be very sensitive to drought periods and may be at greater risk of climate change should groundwater droughts be more commonly prompted by increasing frequency of dry summers. Under current abstraction regimes, the groundwater resource in the Fell Sandstone is not expected to be compromised in future decades (see Younger, 1998). There are relatively few sensitive wetland sites depending on groundwater sources for sustaining them in the Berwick District. While there is clear sensitivity to potential increasing frequency and duration of drought periods, management options for mitigating against water shortages (construction of an artesian borehole into underlying limestone) have been undertaken to safeguard the Newham site (at least in the short-term) by site managers Natural England. Impacts of declining groundwater levels on salmonid spawning grounds are also unlikely, due to the relatively static nature of the water table in close proximity to the channel, where opportunities for localised recharge through the hyporheic zone abound. The number of mine water discharges in the Berwick District is relatively small compared to other north east districts and these are not known to exhibit the flashiness of flow indicative of breakout. Given the mine water at Spittal discharges to the coast it is unlikely to be of high impact even if there was future outbreak.
Description The major coal mine waters in Blyth Valley are at East Cramlington and the Coal Authority pumping scheme at Bates (on the Blyth Estuary to the north of the town). This pumping scheme (soon to be directed to a treatment wetland prior to discharge into the Blyth Estuary) prevents surface discharge of contaminated coal mine water around much of the Blyth area and Seaton Burn. Impacts
Description The most important mine water discharges are in coastal areas around Ellington and Lynemouth. Given these were some of the most recently worked deep coal mines in the region, ground waters are still rising in some coastal areas of the district. These rising levels are currently monitored by the Coal Authority. Impacts While future mine water outbreak due to rebound cannot be ruled out in coastal areas of the District (e.g. Lynemouth and Ellington), these levels are currently being monitored and pumping operations may recommence if deemed necessary. The authors are unaware of any major mine water outbreaks in the district and outbreak risk can be considered less likely here than in central and western areas of the Region, where discharges from shallow workings are more susceptible to ingress and outburst.
Description Impacts
Description There are no known mine water discharges in the District Impacts The Permian aquifer is unlikely to be affected by climate change effects over coming decades if current abstraction rates are maintained. Groundwater levels in the Magnesian limestone have generally been rising over the past 30 years due to changes in coastal pumping regimes suggesting the current abstraction rates are easily sustainable (Younger 1995a). This also suggests any reduction in recharge from climate change effects will not significantly affect the resource. The main concern with the integrity of the water supply concerns rising levels of water in the underlying Coal Measures to the north of Darlington with high sulphate concentrations into the aquifer (see Neymeyer et al, 2006). One of the best north-eastern examples of a groundwater-supported ecosystem occurs at Hell’s Kettles in the south of the district. Here saw-sedge dominated swamp is supported by hard water rising from the Magnesian Limestone forming ponds in natural subsidence hollows in the Upper Permian Marl (Younger, 1995a). Given the site is supplied via upwelling from the large aquifer it is unlikely to be as susceptible to drought as wetlands fed by shallow groundwater systems (such as the Newham Fen example described in the Berwick District), although the risk can not be completely discounted. Nutrient enrichment of the site is believed to be a greater concern to site managers than drought impact at present. The subsidence risk associated with dissolution of gypsiferous strata in the Darlington District has been assessed in detail by Lamont-Black et al. (1999; 2005). The Parkside, Red Hall Lingfield and Frith Moor areas of Darlington have been subject to subsidence in recent years and led to building repairs in the region of £1M. While lowering of groundwater head can promote gypsum dissolution (and subsequent subsidence), investigations have found the water table in the gypsum beds is confined by Quaternary deposits which limits the transverse flows necessary for significant gypsum dissolution (Lamont-Black et al., 2005). Alternative causes of the subsidence are most likely related to clay shrinkage, a process which could well be exacerbated by increasing drought frequency.
Description There are numerous coal mine discharges, particularly in the central and eastern areas of the district where the Coal Measures outcrop. Some of these discharges can exhibit flashiness that may be conducive to breakout if current discharge locations are obstructed. An example of such a site is the Stoney Heap discharge near Annfield Plain which discharges into the Newhouse Burn. Other major discharges in the district include the Morrison Busty mine water treated by the Quaking Houses wetland, again near Annfield Plain, while there are several smaller discharges associated with former drift mines in the Derwent Valley. There is also a small number of mine water discharges associated with abandoned lead mines in the Carboniferous strata in the west of the district. These include discharges at Burnhope and Harehope a short distance south of Edmondbuyers. Impacts Mine water discharges draining shallow sub-surface workings along the Coal Measures outcrop generally exhibit flashiness in flow regime (owing to rapid recharge). In this regard some of the discharges in the Derwentside District (and adjoining districts where there is an abundance of shallow sub-surface former coal mining near outcrop) could be considered more susceptible to breakout than discharges from interconnected workings in large groundwater bodies in coastal areas of the region.
Description Mine water discharges in the District are associated with former coal mining at Bearpark, Metal Bridge, Rainton and Sherburn. Impacts Slope stability has previously been found to be sensitive to localised increases in groundwater head in the vicinity of Kepier Woods, downstream of Durham City, where localised sand and gravel lenses within the Quaternary deposits discharge groundwater to the surface on steep ground. It is likely that the incidence of this process will increase in the event of periods of intense rainfall, given the localised nature of recharge to these lenses and the possibility for saturation from above adding to that already arising from below. There are also zones in the valleys of the Deerness, Browney and middle Wear where the occurrence of such sand and gravel deposits makes this risk at least credible. Localised exacerbation of natural slope failure processes cannot therefore be ruled out under future climate scenarios. There are no reported recent mine water outbreaks in this District. However some of the former workings are in locations where Coal Measures are close to outcrop and may therefore be more susceptible to the ‘flashiness’ in flow exhibited by proximate mine waters in adjacent districts (e.g. Stoney Heap and Edmondsley).
Description The Magnesian Limestone supports several abstractions for domestic supply throughout the district at Seaton, North Dalton, Dalton Piercy, Hawthorn, Thorpe, Peterlee, New Winning and Red Barnes. Discharges from the aquifer are also important in sustaining flows in coastal streams such as the Castle Eden Burn and Nesbill Dean. Discharges from a perched glacial gravel aquifer at Shotton are also important in sustaining a wetland. There are no significant mine water discharges in the district due to the continued pumping operations. Impacts If pumping operations continue at Horden (and / or Dawdon in the future), uncontrolled surface discharges are not expected to commence in coastal areas due to the westward flow of groundwater in this area induced by pumping. This should mitigate against any major mine water outbreak forced by climate change effects (e.g. multi-day rainfall events) in the District.
Description The main coal mine water discharge in the District occurs from Coal Authority pumping operations at Kibblesworth in the Team Valley. This discharge flows under gravity from the former Kibblesworth Colliery to Lamesley where it is co-treated with sewage in a large aerobic reedbed. These pumping operations serve to minimise the extent of uncontrolled coal mine water outbreak in the District. There are however some minor discharges associated with drift workings along the lower Derwent Valley (e.g. at High Spen) and the banks of the Tyne (e.g. at Wylam, Ryton, Blaydon and Dunston). Impacts Pumping operations should minimise the risk of major mine water outbreak in the District. Some of the drift mines in the Derwent valley may be more susceptible to flashiness in flow given the shallow nature of the workings, which may make these sites more vulnerable to breakout.
Description There are no known mine waters in Hartlepool. Impacts
Description There are no current abstractions in the Middlesbrough District. There are no known mine waters in the Middlesbrough District.
Description Coal mine water discharges occur in the district from Kitty’s Drift near the Newcastle Business Park and from Throckley Isabella Colliery into the Reigh Burn near Newburn Country Park. Additionally, there is a minor discharge in the headwaters of the Ouseburn at Woolsington and some minor discharges in the headwaters of the Seaton Burn around Dinnington. Impacts Pumping operations in surrounding Districts should minimise the risk of major mine water outbreak from the large interconnected workings beneath the District.
Description There are two coal mine water discharges on the Briardene Burn to the north of the district and a further discharge at Weetslade near Dudley on the Seaton Burn. Impacts
Description Springs from the Ravenscar Group support groundwater abstractions at Barnaby and Guisborough. There are several mine water discharges associated with ironstone mines along the Cleveland coast (see Younger, 2000b for detail). The principal discharges are at Skinningrove, Saltburn Gill, Eston and New Marske. Impacts A good example of the mine water outbreak risk in the area is provided by the Saltburn Gill discharges. Mine waters into Saltburn Gill currently emerge via 2 sources: the ‘tributary’ discharge on an unnamed tributary of the Saltburn Gill and from a nearby borehole. The ‘tributary’ discharge commenced in 1999 despite mine workings closing some 35 years previously. It was thought to be a result of roof collapse between Lumpsey and Carlin Howe Mines which caused a rise in groundwater level between the collapse and alternative discharge point. This roof collapse was believed to be initiated by surface road construction works (Mason, 2000). Little monitoring of flow in these discharges has been undertaken to offer an indication of variability and potential plugging. Given the previous outbreak and the very high ochre accretion rates (as a consequence of total iron concentrations of >1000 mg/L in the ‘tributary’ discharge at Saltburn for example) there is future possibility of adit plugging and subsequent outbreak at another discharge point. Additionally, instability in some of the workings was cited in causing the 1999 emergence. Therefore, the possibility of this process being exacerbated at the site and in similar mines in the Ironstone Field by increasing frequency of high intensity rainfall events under climate change cannot be ruled out.
Description With Coal Measures groundwater rebounding beneath the Magnesian Limestone plateau in the east of the district, there are no surface mine water discharges here. However in lower elevation areas to the far west of the district (on the district boundary with Teesdale) there are some minor point discharges and significant diffuse mine water discharges along the lower reaches of the River Gaunless where surface waters are in good connection with underlying strata including Coal Measures and Quaternary sands and gravels (see Mayes et al., 2007). Impacts Groundwater levels in the Magnesian limestone have generally been rising over the past 30 years due to changes in coastal pumping regimes suggesting the current abstraction rates are easily sustainable (Younger 1995a). This also suggests any reduction in recharge from climate change effects will not significantly affect the resource. The main concern with the integrity of the water supply concerns rising levels of water in the underlying Coal Measures with high sulphate concentrations into the aquifer (see Neymeyer et al, 2006). It is unlikely that the Skerne headwaters will be adversely affected by any increase in drought severity given the headwaters and associated wetland features have persisted in the past when groundwater levels in the aquifer were some 10m below current levels (Younger 1995a). Similarly, the resource of the Permian aquifer is unlikely to be compromised by increasing drought severity and the major threat to it remains contamination from underlying mine water rebound. The mine water discharges in the far west of the District are unlikely to be susceptible to outbreak given they are fed by large groundwater bodies in the Coal Measures (characterised by relatively steady water levels) in this area and rebound was completed here by the early 1980s (Younger, 2000).
Description Impacts Pumping operations in surrounding Districts should minimise the risk of major mine water outbreak from the large interconnected workings beneath the District.
Description There are no known mine waters in the Stockton-on-Tees District. Impacts
Description Groundwater levels in the Coal Measures strata are largely controlled by pumping operations further south along the coast at Horden and inland at Lumley (south of Washington in the Chester-le-Street District – although pumping is likely to cease here soon). There are minor surface discharges at Usworth (Washington). Impacts While rebound of Coal Measures water levels is continuing following cessation of mining in the lower Wear, it may not be complete for a few decades yet (Younger, 1995b). If pumping operations continue in the central catchment, uncontrolled surface discharges are not expected to commence in coastal areas due to the westward flow of groundwater in this area induced by pumping. This should mitigate against any major mine water outbreak forced by climate change effects (e.g. multi-day rainfall events) in the District. Teesdale District Council Description The main mine water discharges in the Teesdale District are associated with metal mining in headwater areas and coal mining in the central and eastern areas. The important coal mine discharges fall mainly within the Wear catchment, at Lowlands, Woolly Hill, Arn Gill (all draining into the Gaunless – see Mayes et al., 2007 for more detail) and Moor Hill (draining into the Linburn Beck). Lead mine discharges are found at Sharnberry (near Witton-le-Wear) and in headwater areas near Cowgreen. Impacts There was a major outbreak of coal mine water at Lowlands (near Cockfield on the River Gaunless) in June 2000, when a shaft collapsed following an intense multi-day rainfall event. The subsequent outbreak led to short-term, severe contamination (principally with iron) of the River Gaunless along a 20km reach to it’s confluence with the Wear. This is an isolated event, and while this does not rule out the possibility of a repeat, the site provides an example of the type of coal mine locations most susceptible to breakout (shallow workings where Coal Measures are close to outcrop in mid-to-upper reaches of the Rivers Tyne and Wear).
Description
The limestones, Coal Measures and Millstone Grit all support numerous abstractions through the district, principally for domestic purposes in rural areas. Coal mine water discharges are associated with the Lower Carboniferous Coalfield along the South Tyne Valley including large discharges at Lambley, Blenkinsopp, Bardon Mill and Acomb. The Carboniferous strata of the North Pennines also hosts veins of galena, sphalerite, fluorspar and other minerals that have been historically mined. As a consequence, there are a large number of metal mine discharges in the west of the district, notably in the West Allen, and headwaters of the South Tyne. Although falling within Eden District Council, some of the largest metal mine discharges in the North Pennines occur in the Nent Valley which drains into the South Tyne. Impacts There are large reaches of the upper Allen and South Tyne that are flanked by steep sided spoil (e.g. West Allen near Carrshield, Swinhope Burn in the East Allen catchment). While increased frequency of intense rainfall events may exacerbate slope failure processes, the spoil is located in sparsely populated areas and unlikely to be of major impact on infrastructure. Spoil collapse would however introduce large quantities of metal-rich sediment into rivers (which are already largely contaminated) that could be of further detriment to aquatic biota. Evidence of instability in metal mines in adjoining districts is plentiful (see Wear Valley). Metal mines in the North Pennines can be subject to rapid ingress of waters (through mining features, but also due to rapid recharge permitted by outcrop and karstified areas of limestone) in high flow events which can prompt outbreaks. The major coal mine discharges in the catchment are all subject to monitoring and remediation efforts which should minimise outbreak risk. The mines are generally located within sparsely populated areas of Tynedale and thus outbreak is unlikely to be of major impact on infrastructure.
Description There are numerous mine water discharges in the Wansbeck district centred around the former coal mining towns of Ashington, Newbiggin, Choppington and Bedlington. The most major of these is the Bomarsund discharge ~1km west of Guide Post. It is likely that the Coal Authority pumping scheme at Bates (see Blyth District) is preventing surface mine water discharges in the south east of the district. Impacts
Description
There are no major groundwater abstractions in the District. Coal mine waters are largely focussed around Coal Measures outcrop areas in the heavily mined eastern parts of the district. Large discharges include those at Bishop’s Park, Batt’s Drift, Bowden Close and St Helen Auckland (Note: see Teesdale for other discharges in the Gaunless catchment). There are numerous metal mine discharges in the headwaters of the Wear, notably along the Rookhope Burn and to a lesser extent in the Killhope, Wellhope, Bollihope and Stanhope Burns. Impacts The metal mines of upper Weardale have several reported incidences of recent mine water outbreak following extreme rainfall events. The most recent of these is the Rispey mine water discharge which occurred in December 2006 following heavy rainfall. The discharge was considered to be due to obstruction of the adjacent (and hitherto flowing) Tailrace Level discharge, which forced the collapse of a nearby crown hole from which the discharge newly emerged to the Rookhope Burn. Another comparable incident occurred at Rookhope in April 2005. Following 98.5mm rainfall in 48 hours and subsequent increase in river flows, former mine workings under the Rookhope Burn collapsed. Large volumes of water subsequently leaked through the workings and emerged from another entry point to the mine on the Boltsburn Old West Level. River diversionary works were necessary to limit the flow of water into the workings. A similar problem has sporadically affected the Park Level, the adit which provides the principal access to the visitor mine at Killhope Lead Mining Museum, upper Weardale. A line of old ventilation shafts lies along the true right bank of the Killhope Burn upstream of the museum, and under flood conditions, the shafts are occasionally impinged upon by stream waters. Museum staff report that on at least two occasions in the last decade, the entire flow of the Burn has ended up cascading down one of these shafts and re-emerging to surface through the Park Level, temporarily preventing use of the visitor mine and causing localised erosion of the museum site below the adit mouth. Minor civils works are typically instigated after the flood abates, to make good the shaft collars and attempt to prevent recurrence via the same route. Given this continued instability in drainage from metal mines in this area, it would be reasonable to suspect that this will continue into the future and possibly be exacerbated by increasing frequency and intensity of extreme rainfall events.
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