The Tees Barrage Case Study

The Tees Barrage is suitable as an AQA flood-management example, but it should not be presented as a structure built solely in response to flooding. Its original purpose was wider economic regeneration: stabilising the tidal river was intended to make derelict riverside land more attractive for development and recreation. Controlling river levels, reducing tidal effects and preventing localised flooding were important parts of the scheme.

Location and key facts

• The Tees Barrage crosses the River Tees between Stockton-on-Tees and Middlesbrough, just upstream from Blue House Point.
• Construction began in 1991, and the barrage opened in 1995.
• It cost approximately £55 million.
• The barrage is 70 metres wide and impounds approximately 18 kilometres of the formerly tidal River Tees.
• It contains four movable floodgates, each 8 metres high and weighing 50 tonnes.
• The gates are operated by four hydraulic rams, each weighing 21 tonnes.
• The structure also includes a road bridge, footbridge, navigation lock and fish passes.
• It is operated by the Canal & River Trust 24 hours a day, 365 days a year.

Why was the Tees Barrage scheme required?

Flooding and tidal influence

Before 1995, the River Tees was tidal upstream through Stockton and towards Yarm. Water levels rose and fell with each tide, while periods of heavy rainfall could also produce high river discharge.

The lower Tees has a long history of flooding. For example, the River Tees burst its banks during the Great Flood of 1771, severely flooding Yarm. However, the barrage was not constructed in response to one particular flood. It addressed the continuing need to control river levels and reduce localised flooding around Stockton. Stockton Heritage

Urban and economic decline

By the 1980s, Teesside had experienced:

• the decline of traditional industries such as engineering, shipbuilding and steel;
• the loss of thousands of industrial jobs;
• extensive derelict and contaminated riverside land;
• polluted river water and unattractive tidal mudflats;
• limited opportunities for riverside recreation and development.

The proposed Tees Weir development site contained more than 230 acres of derelict industrial land. Parliamentary evidence described regeneration, attracting investment and creating employment as the central reasons for constructing the barrage. UK Parliament: River Tees Barrage and Crossing Bill

An unstable water level

The large tidal range exposed mudflats at low tide and made regular watersports difficult. Maintaining a stable water level was intended to:

• improve the appearance of the river;
• encourage development beside the waterfront;
• create conditions suitable for rowing, canoeing and other watersports;
• prevent polluted tidal water from travelling upstream;
• help change Teesside’s image from an area of industrial decline to one attractive to residents, visitors and investors.

What was the management strategy?

The Tees Barrage is a hard-engineering scheme built across the entire river.

Controlling normal water levels

The four movable gates regulate the amount of water passing downstream. This maintains the river upstream at approximately the level of an average high tide, removing the normal tidal rise and fall.

Managing high river discharge

When heavy rainfall raises the upstream river level, the gates can be opened further. This allows more water to pass downstream and prevents water accumulating behind the barrage and causing localised flooding.

Controlling tidal influence

The structure separates the upstream River Tees from normal tidal changes in the estuary. This prevents high tides from regularly moving upstream through Stockton and Yarm.

The barrage does not remove all flood risk from the Tees. Areas downstream remain tidal, while exceptionally high fluvial flows can still threaten low-lying land upstream. The Environment Agency therefore maintains separate flood-alert areas above and below the structure. Environment Agency: lower Tees and tidal Tees

Additional features

• A navigation lock allows boats to pass through the barrage.
• Fish and eel passes were included to support migration.
• A road bridge and footbridge connect the two banks.
• The stable upstream water level supports rowing, canoeing and other recreation.
• An international white-water course was constructed beside the barrage.

Social issues

Benefits

• Controlling the upstream water level reduces the risk of localised flooding, protecting residents and reducing disruption.
• The river has become a major recreational area for rowing, canoeing, paddleboarding, fishing, walking and cycling.
• The Tees Barrage Park, white-water centre and riverside routes provide accessible leisure facilities.
• The road and pedestrian crossings improve connections between the two sides of the river.
• The barrage and visitor centre are used for school visits and community activities.
• The more attractive waterfront has helped improve perceptions of Stockton and the wider Teesside area.

Problems

• The barrage altered a naturally tidal river into an artificially controlled freshwater or low-salinity reach.
• Navigation was obstructed by the new barrier, although a lock was provided to allow smaller vessels to pass.
• During the planning process, farmers upstream were concerned that the permanently higher water level could raise the water table, submerge drainage outlets and increase the need for pumped drainage.
• People living beside the river may gain a false sense that all flood risk has been removed. Flood warnings remain in place for parts of Thornaby, Yarm and the lower Tees valley.

Economic issues

Benefits

• Homes, businesses and infrastructure around Stockton have greater protection from localised flooding, reducing potential repair costs and business disruption.
• The barrage helped turn previously derelict riverside land into an area suitable for offices, housing, leisure and commercial development.
• It helped support the development of Teesdale Business Park and the wider regeneration of the Stockton waterfront.
• Construction and subsequent leisure, tourism and commercial developments created direct and indirect employment.
• The white-water centre and other watersports attract visitors who spend money in the local economy.
• Before construction, an economic assessment predicted that the wider scheme could attract nearly £4 of private investment for every £1 of public investment and support more than 7,500 jobs. These were forecasts rather than confirmed outcomes.

Problems

• The barrage cost approximately £55 million, making it an expensive hard-engineering scheme.
• It requires continuous operation, monitoring and maintenance. The Canal & River Trust employs a team to operate it throughout the year.
• Its enormous gates, hydraulic rams and concrete-and-steel structure require expensive repairs and replacement. One of the four 21-tonne hydraulic rams was replaced in 2024.
• The benefits cannot be attributed entirely to the barrage because wider river-cleaning, transport and redevelopment projects also contributed to Teesside’s regeneration.
• It does not protect the tidal estuary downstream, where homes, industrial sites and businesses remain exposed to flood risk.
• Further investment is therefore required. The Environment Agency’s more recent Tees Tidelands programme has received over £30 million to improve defences, restore habitats and increase resilience to sea-level rise.

Environmental issues

Benefits

• The barrage formed part of a wider programme that transformed a heavily polluted and unattractive river corridor.
• Preventing polluted tidal water from moving upstream contributed to improved conditions in the impounded river.
• Landscaping around the barrage created parkland, riverside paths and wildlife areas.
• Otters, seals and a range of bird species can now be seen around the river.
• Fish passes, a navigation lock and controlled opening of the main gates provide several potential migration routes.
• Since operational changes in 2015, the gates have provided approximately 1,500 additional hours of fish passage each year.

Problems

• Approximately 18 kilometres of formerly tidal river were impounded. This fundamentally changed the natural tidal regime, water movement, salinity and patterns of sediment deposition.
• Former intertidal mudflats upstream were permanently covered by the higher, stable water level.
• The barrage forms a physical barrier to migratory salmon, sea trout and eels travelling between the North Sea and upstream spawning grounds.
• Fish can become concentrated below the gates, making them more vulnerable to predation by seals.
• Fish passes have not removed the problem completely, so gate operations have been modified, and further improvements to fish passage are being developed.
• Research into the Tees impoundment shows that changing an estuary into a controlled basin affects water-quality processes and sediment movement.

Overall assessment

The Tees Barrage has been successful as a multifunctional management scheme. It regulates the upstream river, removes normal tidal fluctuations, helps prevent localised flooding and has supported major recreational and economic regeneration around Stockton.

However, it is not a complete solution to flooding across the Tees catchment. Flood risk remains upstream during extreme river flows and downstream in the tidal estuary. The barrage has also substantially altered the river ecosystem and continues to create difficulties for migratory fish.

The Tees Barrage successfully combines local flood management with urban regeneration and recreation, but its high cost, continuing maintenance requirements and ecological impacts mean that it must operate alongside flood warnings, habitat restoration and other flood-management measures.