Case Studies

Delivering the successful design and construction of a large diameter emergency drawdown siphon at one of Yorkshire Water’s largest reservoirs

New £6.5m water storage tank completed on schedule replacing 90 year-old asset

Grade II listed structure that underwent refurbishment to address safety concerns in the draw-off tower and spillway

Refurbishment of a 90-year-old potable water storage tank in Bedfordshire without compromising water quality

West Hallington Reservoir is a Northumbrian Water Group (NWG) asset situated 1km to the northeast of the village of Colwell in the Tynedale district of Northumberland. The reservoir was constructed between 1884 and 1890 for Newcastle & Gateshead Water Company for the purpose of municipal water supply. The reservoir was built adjacent to the earlier […]

Birds Park Reservoir is no longer used for water supply and is enjoyed by the community for recreation. Constructed around 1850, the dam is an earth embankment, 45m long and 13.8m high, perched above a residential area near Kendal, Cumbria. There are no historical drawings, and limited site investigation data was available but it was […]

Bourn Reservoir is an above-ground reservoir complex located approximately five miles outside Cambridge, England. Only one tank was still operational after the other two were removed from service due to natural degradation. A new tank was required to meet demand from large-scale developments in the supply area. A review was conducted to ascertain the total […]

Clough Bottom Impounding Reservoir (IR) is an earth-fill embankment reservoir located on the eastern edge of the West Pennine Moors, around 4km north east of Rawtenstall, Lancashire. The reservoir is currently used for public water supply and compensation flows. The reservoir was formed by the construction of an earth embankment across the Whitewell Brook and […]

In the summer of 2020, the water industry was set a challenge by its regulators to identify ways to support the country’s green economic recovery from Covid-19. Severn Trent responded with a number of proposed programmes, including Decarbonising Water Resources (DWR), the subject of this paper. The objective of the DWR programme was to provide […]

South West Water’s (SWW) Hingston Down Reservoir site is located on an exposed Cornish hilltop and contains two service reservoirs which supply nearby villages with potable water. Originally there was only one reservoir at the site and there was no way of being able to take it out of service for cleaning, so a Braithwaite […]

Forming part of Southern Water’s (SW) Hampshire supply region, the Isle of Wight (IoW) is located just off the south coast of England and is divided into two water distribution zones (WDZ), namely IoW North and IoW South. The IoW South comprises major towns of Ryde, Sandown, Shanklin and Ventnor with multiple villages and more […]

King George V Reservoir (KGV) is an operational raw water storage reservoir located in the Lea Valley at Walthamstow and is a Site of Special Scientific Interest (SSSI) with restricted access. It is controlled by Thames Water’s Lea Valley/North London Abstraction Group based at Coppermills AWTW. Seepage through the clay core at the north-east of […]

Located near Maerdy in South Wales, Lluest Wen Reservoir is a Category A Large Raised Reservoir as defined by the Reservoirs Act 1975. The reservoir is impounded by a 200m long, 25m high earth embankment dam across the Rhondda Fach River and currently impounds 1.07Mm3 of water. Construction of the reservoir was originally completed in […]

Lower Barden Reservoir is the lower of two reservoirs located near Bolton Abbey within the Yorkshire Dales National Park. The reservoir is an impounding reservoir with a crest length of approximately 640m and a maximum height of 28m with a capacity of 2.23 Mm3. The overflow is located on the right-hand side of the embankment […]

United Utilities and Managed Service Provider (MSP) Costain have delivered improvements to the existing spillway at Rivington Upper Impounding Reservoir in Lancashire. The team worked collaboratively, undertaking a complex construction programme in challenging conditions, while managing the operational needs of the reservoir site and popular recreational area. The main objective was to upgrade the existing […]

Usk is a large raised reservoir formed by an earth embankment dam, which completed constructed in 1955 with an approximate capacity of 12,268,000m3. The dam is 480m in length, with a maximum height of 31m, and supplies raw water to Bryngwyn Water Treatment Works and as well as providing compensation water to the River Usk, […]

Whitehall Distribution Service Reservoir (DSR) is located on Stronsay, one of the north isles in Orkney, located 25 miles to the north of the Orkney mainland. The isle is home to 350 residents and is accessible by public ferry and plane. The Stronsay WTW that feeds the DSR is 300m to the south of the […]

Dean Clough Lower Impounding Reservoir (IR) is a Category A, earth-fill embankment reservoir, located approximately 6km north-east of Blackburn in Lancashire. It is currently used to provide storage for public water supply. It was formed by the construction of an earth embankment across the Dean Brook river and is the lower reservoir in a cascade […]

Drumaroad Water Treatment Works (WTW) supplies water to many households throughout Northern Ireland. A 2013 report commissioned by NI Water identified the need for increased potable water storage facilities within the Drumaroad Supply Zone to reduce the risk of water shortages under certain network situations. As part of a £13m investment to modernise the existing water infrastructure […]

Heaton Park Reservoir is located within Heaton Park, approximately 5 miles north of Manchester city centre. The reservoir is over 90 years old and has the capacity of 2,800,000m3 at top water level. The reservoir was previously used to store treated water for the Manchester Ring Main from Haweswater and Thirlmere aqueducts. However, since the […]

The brick-built Maiden Lane Reservoir holds 67 million litres of water and supplies a population equivalent of approximately 200,000 people in north-east London.  The reservoir is located in Dartmouth Park which opened to the public in 1972 and is in the London borough of Islington.  The top of the embankment gives an open semi-panorama of […]

Pant-yr-Eos is a large raised reservoir situated approximately 2km east of Risca in the City of Newport, Monmouthshire. It is impounded by a 27m high, 280m long embankment dam with clay core, and has a storage capacity of approximately 600 Ml. The reservoir was completed in 1878 for provision of water supplies to Newport. To […]

The construction of Plas Uchaf Reservoir was completed in 1870. It has an embankment dam that is approximately 15m high, with a puddle clay core. It has a retained capacity of 225,500m3 and a surface area of 3.5ha. The reservoir is formed across a tributary of the River Elwy, with Dolwen Reservoir located approximately 0.7km upstream of Plas […]

The Queen Elizabeth II (QEII) Reservoir is a raw water reservoir in South West London that is owned and operated by Thames Water. The reservoir holds over 19 million litres of water, equating to 10% of the raw water storage for London. Once treated, this provides clean potable drinking water for millions of people across […]

Swinsty Reservoir is the third in a cascade of four impounding reservoirs in the Washburn Valley, North Yorkshire. The reservoir is impounded by a 490m long, 24m high earth-fill embankment dam with a central puddle clay core, storing 3.94 million cubic metres at top water level. The overflow is located on the right-hand side (RHS) […]

The Ynys-y-Fro Reservoir system is situated 1km north-east of High Cross, Newport. The system comprises two reservoirs in cascade: an upper ‘subsiding’ reservoir and a lower ‘old pond’ reservoir. The upper reservoir is immediately upstream of the lower reservoir. The lower reservoir was constructed as an earth embankment dam and was built for the supply […]

Dolwen Reservoir is a Category A Large Raised Reservoir as defined under the Reservoirs Act 1975. It is located on a tributary of the River Elwy, 0.7km upstream and north of Plas Uchaf Reservoir, near Abergele, Conwy, Wales. It was constructed in 1905 and has a capacity of approximately 288,185m3. Dŵr Cymru Welsh Water commissioned […]

Lower Neuadd Reservoir is located in the Brecon Beacons, 5km north of Merthyr Tydfil in south Wales. The reservoir, which is an embankment dam, was constructed in 1884. It is the middle of a cascade of three reservoirs, with Upper Neuadd situated 3km upstream of the much larger Pontsticill Reservoir. Lower Neuadd Reservoir had a […]

Ludham WTW supplied 2.1 million litres a day (MLD) of treated water to 2,464 properties in Ludham and Martham whilst originally being fed by Ludham boreholes, with emergency supply coming from East Ruston boreholes. This £7.6m scheme addressed area growth and abstraction licence challenges by combining different schemes to deliver an efficient solution for customers […]

In 2016, United Utilities was issued with a Service Reservoir Cleaning notice by the Drinking Water Inspectorate (DWI) as part of the Company transformation programme. Inspecting, cleaning and maintaining the reservoirs first required a batch of projects to provide the facility to isolate five existing service reservoirs (SRs) from the water network, whilst maintaining supply […]

The Uckington Borehole Capital Maintenance (BCM) and Restoring Sustainable Abstraction (RSA) Treatment Project set out to achieve the goal of an ecological improvement of the River Worfe while safeguarding the public water supply to the Telford area network. Over-abstraction from the River Worfe was impacting the achievement of Good Ecological Status under the Water Framework […]

The Hereford Water Network is dependent on a single source of supply from the River Wye and Dŵr Cymru Welsh Water identified a need to assess the resilience of the network to maintain customer supply during any future loss of source supply events. The resulting hydraulic assessment identified the requirement to increase the available storage […]

Blackmoorfoot Reservoir, a storage reservoir situated south-west of Huddersfield in West Yorkshire, was constructed between 1871 and 1876 at a cost of £260,000. It has a capacity of over 700,000 gallons and covers an area of 102 acres and provides raw water to Blackmoorfoot WTW, which supplies treated water to Huddersfield and surrounding areas. The […]

During AMP4, Thames Water Utilities Ltd (TWUL) undertook low flow investigations for the Letcombe Brook, in the Wantage area of Oxfordshire. It was determined that the abstraction at Childrey Warren Water Treatment Works (WTW) was having an adverse impact on the river flows and the local environment. A subsequent review of options which included augmentation, […]

South East Water’s College Avenue Water Treatment Works in Berkshire supports the Maidenhead water supply infrastructure. It extracts raw water from three boreholes and three chalk wells, which is then dosed with sodium tripolyphosphate (STPP), aerated, passed through granular activated carbon (GAC) absorbers, and finally injected with sodium hypochlorite to super-chlorinate it before entering the […]

Llyn Brenig impounding reservoir is located in the Denbigh Moors in North Wales. It was constructed in 1975 and was officially opened by the Prince of Wales. It forms part of the River Dee regulation to manage flow into the Dee via the Afon Alwen. The reservoir has a capacity of around 60 million cubic […]

Lough Fea Water Treatment Works supplies water to approximately 24,000 Northern Ireland Water customers, with the Lough Fea Clear Water Basin South supplying over 10,000 people in Cookstown and surrounding rural areas. A 2013 report commissioned by NI Water identified the need for increased potable water storage facilities within the Lough Fea Supply Zone to […]

United Utilities has completed the refurbishment of Aubrey Street Reservoir, a 40Ml underground service reservoir located just outside Everton and serving Liverpool district. Treated water for the 41-year-old reservoir is pumped in from Huntington Water Treatment Works in Chester. The main driver for the project was water quality, which risked being compromised by heavy ingress […]

During AMP4, Thames Water Utilities Ltd (TWUL) undertook low flow investigations for the Letcombe Brook, in the Wantage area (Oxfordshire). It was determined that the abstraction at Childrey Warren Water Treatment Works (WTW) was having an adverse impact on the river flows and the local environment. A subsequent review of options which included augmentation, works […]

Talybont is a Large raised reservoir situated in the Brecon Beacons National Park approximately 30 miles north of two of the most populated cities in Wales; namely Cardiff and Newport. Construction of Talybont Dam began in 1932 and ran through until 1939. It was conceived out of a requirement to supply treated water to the […]

Ten Acre Impounding Reservoir (IRE), located in Haverah Park near Harrogate, is owned and operated by Yorkshire Water (YWS). The reservoir is impounded by an earth-fill embankment dam, approximately 17m above natural ground level at the highest point, with a capacity of 150,000m3 at top water level. The reservoir was constructed by Harrogate Waterworks Company […]

Warland Impounding Reservoir (IR) is situated on the western slope of Blake Moor, above Littleborough, Lancashire. The reservoir was originally constructed around 1857 by the Rochdale Canal Company to maintain water levels in the Rochdale canal, and was considered to be one of the largest dams in England at the time. It has a 1500m […]

The Water Supply GRID is the largest scheme ever undertaken by Wessex Water and provides important new infrastructure for the south-west region with resilience connections to Bournemouth Water, Bristol Water and South West Water via Wimbleball Reservoir – it is effectively a south-west area regional grid (see Figure 1 below). It has improved interconnectivity within […]

The Elan Valley Aqueduct (EVA) is a Victorian water structure built between 1893 and 1904. The aqueduct transports water entirely by gravity from the Elan Valley in Wales to Frankley Water Treatment Works in Birmingham, and comprises a combination of cut and cover conduits, siphons and tunnels. Over 100 years on and this aqueduct still […]

Cowleigh Distribution Service Reservoir (DSR) and Lower Wyche DSR are located to the north and south of Great Malvern, Worcestershire and are overlooked by the Malvern Hills. Cowleigh DSR receives water from Powick Pumping Station and the Southern Strategic Main, whilst Lower Wyche DSR receives water from Bromsberrow WTW which is borehole site. Severn Trent […]

The water industry is highly-regulated, most particularly to ensure that drinking water is safeguarded and fit for human consumption. The Drinking Water Inspectorate (DWI), formed in 1990, holds responsibility for regulation in England and Wales. The DWI inspects the laboratories where water companies rigorously test their drinking water and ensure that water operations are of […]

Built under the Bradford Corporation Waterworks Act 1890, Gouthwaite Impounding Reservoir (IRE) forms the lowest of a cascade of three reservoirs in Upper Nidderdale, all designed by their chief waterworks engineer. The upper two reservoirs, Angram and Scar House, supply water along the Nidd Aqueduct to Bradford. Gouthwaite IRE was built 11km downstream to provide […]

A ‘product-based’ approach to service reservoir construction is revolutionising the way MMB are constructing a new multi-million-pound distribution service reservoir (DSR) for Severn Trent Water (STW). To boost productivity in the construction process, the new 43ML reservoir is being treated as a ‘product’, manufactured largely off site in controlled-conditions, before being assembled on site near […]

Island Barn Reservoir is located in West Molesey near Hampton Court on the Surrey/London border. The reservoir is a non-impounding reservoir and is retained by an earth fill embankment with puddle clay core approximately 10.8m high and 2,700m long. The reservoir has a stated capacity of 4,191,000m3 and a surface area of 489,700m2, when full […]

Lockwood Reservoir is one of ten Walthamstow reservoirs in north London and makes up part of Walthamstow Wetlands; Europe’s largest urban wetland nature reserve. It is also a Site of Special Scientific Interest (SSSI) and a Special Protected Area (SPA). The Wetlands attract 250,000 visitors a year and is a key site in London for […]

Stanford Reservoir is an impounding reservoir that is located in the upper reaches of the River Avon. The catchment area of the reservoir is 55.2km2. This scheme was developed following a Section 10 Report (MWH – now Stantec UK – 2014), where after the re-categorisation of the reservoir from B to A, the Inspecting Engineer […]

Upper Chelburn Impounding Reservoir (IR), located near Rochdale on the east Lancashire moors, is owned and operated by United Utilities (UU), providing compensation water to the nearby Rochdale canal. The reservoir is impounded by northern and southern earth-fill embankments (Figure 1), with a resulting capacity of 236,000m3. The 16.5m high northern embankment was constructed between […]

Usk Reservoir in Brecon is situated south east of Llandovery and approximately 5km to the west of Sennybridge. The reservoir is an existing 12.3Mm3 reservoir in the Brecon Beacons National Park in South Wales. It is impounded by a 31m high, 480m long embankment dam with a clay core, which was constructed in 1955. The […]

Woodgate Hill Service Reservoir No. 2 (SR2) was commissioned in 1963, providing a total capacity of 269Ml and a throughput that equates to 20% of the regional water demand. The reservoir was built in to the hillside with an excavation of around 380,000m3. With a footprint of 47,000m2, at the time of construction, Woodgate Hill […]

The existing Ambergate Reservoir was commissioned in 1907 and formed a part of the Derwent Valley Aqueduct receiving water from the Upper Derwent Valley. Water treated at Bamford WTW is delivered to Ambergate Reservoir by gravity via the aqueduct. The existing reservoir had a capacity of 128Ml supplying water to the cities of Derby, Nottingham […]

Yorkshire Water’s Butterley Reservoir is located in the Wessenden Valley, West Yorkshire, with construction completed in 1906. The reservoir dam has a puddle clay core and a spillway constructed with local traditional stone. Due to fissures in the surrounding rock, leakages around the dam were experienced during the original commissioning phase, leading to a longer […]

Digley Impounding Reservoir (IRE) is located in Holmbridge, Huddersfield. The valve tower associated with the reservoir had corroded access metalwork which did not meet current health and safety standards. The project replaced all the corroded access metalwork within the valve tower with new Yorkshire Water Asset Standard compliant metalwork, improving safe access within the tower. […]

Scottish Water has undertaken a £120m drinking water improvement scheme in Ayrshire to meet water quality compliance objectives and provide increased resilience of supply to five operational areas. The scheme involves the transfer of water from the Milngavie WTW located north of Glasgow to the Ayrshire region southwest of the city. The scheme makes use […]

Llyn Teifi Reservoir is situated in a remote area on the western slopes of the Cambrian Mountains in Ceredigion, west Wales, and was created in the early 1960s by raising a natural lake. It is impounded behind six embankments constructed across natural low spots along its south-western margin, covering an area of just over 25 […]

Service reservoirs play a key, if sometimes unsung, role in the supply of clean water within the UK. While most are far less visible and well known than the open reservoirs and other sources they serve, they balance supply and peak demand and ensure that customers’ taps never run dry. The refurbishment of one such […]

The innovative use of a spray applied structural concrete ‘shotcrete’ lining is a cost and programme effective alternative to ‘traditional’ in situ or precast concrete repair, or re-construction of masonry reservoir spillways. This construction methodology was used successfully across three masonry spillways of varying geometries to prolong the operational life of the ageing structures, whilst […]

The original Outwoods Reservoir (No.1) was constructed in 1882 in Burton on Trent. An additional Reservoir (No.2) was added in 1962 in response to increased demand on supply. In 2017, South Staffs Water awarded Stonbury the contract to replace Reservoir No.1 which has proven increasingly expensive to update and maintain and was taken out of […]

United Utilities (UU) is the statutory undertaker for 132 impounding reservoirs (IRs) retained by earth-fill embankment dams which fall under the requirements of the 1975 Reservoir Act. Before the era of ‘Pennine’ type clay core construction techniques, many impounding reservoirs that were constructed around the turn of the nineteenth century were substantially homogenous, comprising of […]

Dundry Reservoir and Pumping Station is located just 6 miles south of Bristol and provides a reliable supply of potable water to a population of circa 8000 located in the villages of Dundry, Highridge and Withywood. The original reservoir built in the 1950s did not have sufficient capacity for operational and emergency storage to meet […]

Grafham WTW is located near Huntingdon and serves a population of 829,000, including Northampton, Huntingdon and Bedford. It is estimated that approximately 614,000 of these would be affected by a major outage at Grafham WTW. As part of Anglian Water’s AMP5 Final Business Plan programme, the Grafham WTW Resilience scheme was identified to mitigate the […]

Jackson’s Edge Service Reservoir (SR) is a water supply scheme that will provide increased security to the network through the provision of a new 18Ml capacity, twin compartment SR on the site of the existing 103 year old SR. The £7.5m project has adopted a Design for Manufacture and Assembly (DfMA) approach, saving approximately £2m […]

Located in the Brecon Beacons on the outskirts of Merthyr Tydfil, Pontsticill Reservoir and treatment works date from 1927. The Reservoir holds approximately 13.6 gigalitres of water and is a key element in the supply of drinking water to 106,000 customers in this region of South wales. In recent times Dŵr Cymru Welsh Water has sought […]

Sunnyhurst and Earnsdale Impounding Reservoirs (IR) are situated 1.5km to the west of Darwen town centre in Lancashire and are owned and operated by United Utilities. Sunnyhurst IR is one of the raw water sources of Fishmoor WTW, which feeds Blackburn and the surrounding areas (population equivalent of 100,000 people). Earnsdale IR provides compensation water […]

Upper Neuadd Dam is a Grade II* listed structure, situated in the heart of the Brecon Beacons below Pen y Fan in the Taf Fechan valley, about 13km north of Merthyr Tydfil. It is owned and operated by Dŵr Cymru Welsh Water and is the upper dam in a cascade including Lower Neuadd and Pontsticill […]

Construction of the second largest service reservoir in Europe, a secure water supply across the East Midlands for a further 100 years

Preservation of an asset to provide a low-maintenance safe crossing of the reservoir for the public

Reservoir discontinuance – removing reservoir from the Reservoirs Act 1975 by excavation of over 20,000m3 of embankment fill

Compliance with the Reservoirs Act (1975) provision of sufficient drawdown capacity

Increasing the spillway capacity of three historic impounding reservoirs within Dartmoor National Park

Largest anchoring scheme for Scottish Water

First ever precast spillway for Scottish Water

Wessex Water are providing additional security of supply and additional strategic storage within the water distribution network in West Dorset

Innovative solutions to meet challenging site conditions and maintain compliance with the Reservoirs Act 1975

Victorian pumping station refurbishment within a Site of Special Scientific Interest

Pushing the boundaries of Building Information Modelling & precast concrete engineering in the water industry

Investigating and addressing deficiencies in the capacity of the overflow system

Future-proofing United Utilities reservoirs

Improvements to a 238 year old Derbyshire reservoir including an improved draw off system

Scottish Water’s measures to ensure resilience of supply for customers in Dumfries and Galloway

Monitoring with fibre optics

Wessex Watre’s upgrade capacity by 5Ml to ensure security of supply and meet future area demands

A new grout curtain constructed beneath Wimbleball Dam has reduced leakage to the lowest recorded rate since construction

New pumping station to extract 120Ml/d of raw water from the River Stour to supply the Abberton Reservoir

Raising the height of a reservoir and bell-mouth spillway required innovative thinking

£9m investment offers security of supply and storage to 70,000 customers in North Wales

Concrete repairs to improve the life of the structure

AMP5 security of supply

‘Dark-side’ solution to reduce the level of THM’s at Highwood raw water storage facility near Southampton

Replacement of two existing buried steel mains to protect reservoir embankment from risk of erosion

Building a complex hydraulic model of London’s strategic assets, including 4,000km of mains, 70 service reservoirs and over 100 pumping stations

Upgrade of physical and electronic security measures to strategic water assets across the Severn Trent region

Increasing the capacity of Abberton Reservoir to meet the forecast population increase in Essex

The restoration of Whicham Beck provides ecological benefits, risk reduction and reduced OPEX costs

Lowering a reservoir’s water level without introducing suspended solids into the water discharge

A reservoir within a reservoir to improve Coventry’s water quality

Spillway improvements and clay core raising

Design and installation of a geomembrane lining

Water abstraction from the River Arun safeguards supplies to customers in Sussex

New 5Ml service reservoir to maintain supplies to 12,500 customers in the Hindhead, Grayshott and Bramshott

Innovative pumping stations for abstraction of raw water from two flooded china clay quarry pits

Considerate construction in the Peak District National Park

New spillway to replace storm damaged overflow structure and prevent risk of dam water failure

Alternative to secondary treatment plant saves millions

New service reservoir required to improve the security of supply

Repairs to a remote reservoir in Cumbria

£12.2m project to construct 2 reservoirs (22,5Ml) ensuring Thames Water meets the increased demands

New 10Ml service reservoir constructed at Cranbrook

Drainage and waterproofing of a critical service reservoir near Hull

B&V demonstrates the effectiveness of a fully integrated consulting and construction business

Refurbishment of service reservoir to prolong operational life

Improved security of supply to two Yorkshire areas

Capital investment at service reservoirs in Yorkshire

Reduction of manganese & geosmin deposits in supply networks

Sutton Bingham Dam remedial work

In-situ structural secondary lining of existing tunnel

Reservoir becomes part of Bristol Water Northern support scheme

Rebuilding reservoir in area of outstanding national beauty

Increases security of supply & maximises economical operation

Yorkshire Water invest £14 million to achieve compliance & security of Bridlington supply

New service reservoir for Mid-Kent Water

To boost existing water supply during peak periods

Resolving existing operational water supply problems

Overflow remedial works for 4 Yorkshire reservoirs

Anglain’s new service reservoir for Bedford

Membrane repairs to a leaking reservoir