Thames Water has announced that his most important new reservoir near Abingdon, Oxfordshire, now probably costs between 5.5 billion and 7.5 billion GBP. After more detailed design work, they triple his previous estimate.
The company submitted its gate Three package for the South East Strategic Reservoir Option (SESRO) to the regulatory authorities and marked a move from the early feasibility into detailed deliverability planning. This submission was accompanied by a dramatic revision of the likely costs of the program: What was described in earlier plans as 2.2 billion GBP is now presented in the documents of the regulatory authorities as a program with a state -mandated costs of 5.5 billion GBP up to 7.5 billion GBP, and a Thames Water estimate of around £ 6.6bn.
The Sesro proposal, which is sometimes referred to as the Abingdon Reservoir, is designed as a non -reigning, fully established raw water bearing device in the upper theme with a capacity of up to 150 mm3. In practice, the reservoir would be filled from the Thames by abstract excess winter flows, kept this water and then made it available on several routes: to put water back in the thams to make a newaction again; Transfer of raw water to the Swindon and Oxfordshire network from Thames Water; Or provide water directly via a thaes of treatment and distribution by southern water.
The program is advanced on behalf of three sponsors – Thames Water, Affinity Water and Southern Water – and is monitored by Rapid, the GATED process of the supervisory authorities for important water resource projects.
Thames Water says that the price jump reflects the point that it has achieved in project development. Gate Three is intended to put a proposal from the early concept into a phase in which the technical details and the construction route for the supervisory authorities and the market are sufficient to assess the availability.
In its submission, the company found that almost three years since its Gate Two material have passed, where it has made the estimate of 2.2 billion GBP. During this time, further ground, hydrological and environmental examinations and a much deeper program for design work were carried out. Therefore, the Gate Three package identifies much more of the activation work, tunnel and pump infrastructures, environmental protection and material negotiation agreements that underpin the construction work. The company also refers to inflation printing on the buildings and the states, which deliberately modeled the estimate in today's prices and provided an early, conservative range before procurement.
Thames Water said that about half of the cost of the program is borne by its 16 million customers, the rest being shared with Affinity and Southern Water customers. The supervisory authorities and ministers will now be forced to weigh this proposal if the project progresses through statutory consultation and the DCO process (understanding of development).
What are the design changes?
Beyond the headlines, the Gate Three Environment Documents show a number of essential design changes.
With regard to earthworks, the engineers have checked the geometry and reservoir form, foundation and drainage concepts, refined loans and settlement ratings as well as the changed protection in the interior such as Riprap and wave reduction. These were informed by the attempts at the embankment that Costain and ARUP-Binnies carried out on site.
The intake and sacrificial sizes and wave diameter were increased to support a preferred emergency route through a river tunnel (originally considered a secondary channels were removed). The inner diameter of the river tunnel has increased from 4.2 m to 6 m and a length of the secondary feed by 1.4 km. The internal diameter of the recording/off structure has increased by around 2.5 m to take into account the larger tunnel.
The layout of the admission/pumping station was revised from a rectangular box into three connected cells to record revised plant and process arrangement. The pumping station has increased the size to take into account the option products and the integration requirements.
The inner diameter of the reservoir tunnel has increased by approx. 1 m to 5.8 m, which provides for two pipes with a diameter of 2.2 m speed. This enables a higher proportion of the emergency drawda to go through the reservoir tunnel.
The diameter of the main reservoir tower was set at 31 m. This larger diameter requires a revised design, including the addition of piles.
There were also significant changes to the design of watercourse redirections and drainage. This includes the first concept design for the integration of location drainage with protection plans for the Wilts and Berks Canal.
Thames Water also configured rails next to him and moved it slightly west of the previous location to alleviate the environmental impact. The proposed arrangement of the siding and material handling area was developed to reach the current location and approved with a network rail as a preferred solution.
The plans for the streets in the region were matured after discussions with the Oxfordshire County Council about the location, the design and modeling of junction, including the development of the initial horizontal motorway and vertical orientations. This includes the orientation and location of the intersection of the main access road with the A415.
Other details that have developed are those that relate to the detour of supply companies, the designs of recreation and educational institutions, and how the system is integrated into the development of the most important new water transfer systems that are in development.
Timeline and financial situation
The Thames Water Gate Three Entering makes it clear that these changes would not change the goal of the project of the 2040 project.
What happens next is relatively well assigned to paper when it is politically affected in practice. Thames Water and his CO sponsor planning consultations by the end of 2025, a DCO submission in 2026 with the aim of agreeing in early 2028. This would be set up in the second quarter of 2029 for a construction start, followed by staged commissioning to provide the water around 2040.
However, the updated cost envelope complicated the procurement, financing and consent policy. The company says that it tries to promote costs and procurement models before the tender to avoid a strong change during the construction. The opponents will push for stronger tests of alternatives and a sharper, independent testing of the new figures.
The financial background complicates the procedure. After a time of dramatic restructuring and emergency loans, Thames Water is heavily indebted. Its equilibrium position and the controversial negotiations on industry costs mean that each reprepraisal attracts an intensive examination in several billions of pounds.
Campaign groups and some local politicians have already submitted legal challenges or clarified their intentions. The opponents argue that the system is costly, environmentally harmful and that alternatives – leak reduction, minor transmissions and reuse – are not sufficiently prioritized. The supporters counters that the southeast is exposed to acute long -term short -term risks and that strategically legal memory is the only way to offer a robust drought resilience on a regional scale.
These developments underline the difficulty of appreciating the mega project costs in the early phases when location examinations, soil conditions and system interfaces are still solved – and underlines the political compromises that are confronted with a government that wants to accelerate the national infrastructure and at the same time contains invoices.
Thames Water now has to sell a much larger bill than a few years ago to its supervisory authorities, their CO sponsors and ultimately to the customers who are asked to exceed a large part of the drought price, to his co -sponsors. In the coming months of the consultation, the legal review and the commercial market, it will be determined whether a strongly revised sesro can squares the technical ambition with political and financial reality.
Thames Water 'Apply lessons from other major projects'
Thames Water Strategic Water Resources Director Nevil Muncaster said: “We published our report on three in Oxfordshire in Oxfordshire in Oxfordshire in accordance with the regulatory process, which we pursue for your design and development.
“The report marks a critical milestone in our development of the reservoir. It reflects the extensive work that we have done to develop our proposed design and better understand what it takes to deliver it.
“If we work through the development process, we turn lessons from other major projects in Great Britain, wherever we can.
“The reservoir is a critical piece of infrastructure to cover the future water requirements in the southeast.
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