Finance and Sustainable Growth Secretary
John Swinney
Scottish Parliament
Wednesday, December 19, 2007
___________________
Presiding Officer, for some time, Ministers in this and the last Government have considered critical issues in relation to the condition of the existing Forth Road Bridge.
Ministers have recognised the pivotal significance of this crossing to the connectivity and the future of the Scottish economy.
A number of reports were compiled by the last Administration and this Government has continued this work.
In the Transport Statement in June, we announced a programme of public information exhibitions to present the full facts which have informed the reports received from Transport Scotland on the form and location of the new crossing of the River Forth.
In parallel with this public engagement, further work has been undertaken to assess the viability of tunnel options and this work has now concluded. This has been essential to ensure all options have been properly considered and the Government is able to recommend a clear and fully assessed proposal.
The Government's purpose is to increase sustainable economic growth. We recognise the continuity of the Forth Replacement Crossing as a key contributor to achieving the Government's purpose.
The existing Forth Road Bridge has served Scotland well, carrying far more traffic than was ever envisaged. The effects of this traffic and the impact of the Scottish climate have taken their toll on the structure and despite being strengthened and maintained during its life, the bridge faces an uncertain future.
The Forth Estuary Transport Authority (FETA) are working to protect the integrity of the bridge by putting in place measures to dry out the main cables.
We will not know whether these have been successful until 2012, which, when set against previous announcements by FETA that the crossing may have to close to HGV in 2013 and all vehicles by 2019, is impossibly late to begin thinking about this problem.
Doing nothing is not an option. Work is required now to protect this crucial link in Scotland's transport network and to minimise the risk from the existing bridge not being available, either altogether or closed for considerable periods of time to allow the cables to be replaced if that proves possible.
Options for the Future
In appraising each option, consideration has been given to six assessment criteria:
· impact on the environment
· operating restrictions
· operational risk
· cost
· cost risk
· time to construct
Four options have been identified as possible replacement crossing types and have been fully considered and appraised:
· A suspension bridge
· A cable-stayed bridge
· A bored tunnel
· An immersed tube tunnel (ITT)
I will set out the consideration given to each option and then explain how each option has performed against the 6 assessment criteria.
Cable Stayed Bridge
A cable-stayed bridge would run from the northern shore from just west of the existing road bridge to a point west of South Queensferry.
It would consist of a dual two-lane carriageway with hard shoulders to provide an area for breakdowns to pull off. The traffic consequences of breakdowns on the existing Bridge are well known and hard shoulders would improve reliability. A cable stayed bridge would be open to all classes of traffic and would include provision for pedestrians and cyclists to cross the bridge.
This option would take approximately five and a half years to construct since it extends incrementally from the three pylons which support the deck, allowing work to be carried out on a number of locations at once. A cable-stayed bridge would cost between £2.79 billion and £3.63 billion in outturn prices including VAT with a Benefit to Cost Ratio of 4.57.
Increasing the width of the bridge deck to accommodate two lane multi-modal systems for public transport would add between £450 million and £580 million to the cost of this option.
Suspension Bridge
A suspension bridge would run along essentially the same route as the cable stayed option, and would also consist of a dual two-lane carriageway with hard shoulders.
The suspension bridge has a benefit to cost ratio of 4.06 and the estimated cost of this option including multi-modal provision is between £3.17bn and £4.11bn in outturn prices including VAT. It would be constructed in approximately 6 years, due to the sequence of constructing a suspension bridge in an essentially linear fashion.
Bored Tunnel
The cross-section of bored tunnel suitable for a crossing of the Forth is limited by the ground conditions in the area. The proposed tunnel upstream of Rosyth is a twin bore tunnel approximately 8.5 kilometres long, and due to location of the tunnel requires some 5 additional kilometres to be travelled by the vast majority of vehicles compared with the existing Bridge.
It requires ventilation shafts on both banks of the Forth, which would need to be located to avoid the environmentally sensitive sites of the Forth including Special Protection Areas (SPA). This tunnel would generate approximately 4 million tonnes of spoil which would require disposal.
The ground conditions of the Forth impact upon the size of the tunnel boring machine which may be used, and therefore incorporating multi-modal options into a bored tunnel would require an additional tunnel.
Tunnels are restricted in the goods that may be transported through them, for example flammable goods, including whisky and oil. In delivery terms a bored tunnel would take approximately 7.5 years and would not accommodate pedestrian or cycle access due to the safety issues of having these vulnerable users in a tunnel. A bored tunnel has an estimated cost of £4.08bn and £5.27bn in outturn prices and a benefit to cost ratio of 2.61. Providing an additional tunnel for multi-modal use would add in excess of £1bn to this cost.
Immersed Tube Tunnels (ITT)
ITT technology takes advantage of the ability to construct the tunnel sections in a dry dock before floating these into position and lowering them into a trench on the bed of the river. The tunnel must then be protected from accidental damage by shipping and dredging and in the Forth must be below the level of the existing river bed.
An alignment for an immersed tube has been considered and would be located immediately upstream of Rosyth. While connecting to the wider transport network, especially the proposed Rosyth bypass, the indicative alignment impacts directly on the Rosyth Dockyard.
The ITT would comprise some 2.3km of the 8.2km that make up this crossing with the remainder being provided by a combination of traditionally mined sections and cut and cover excavation.
An ITT requires a large trench to be excavated in the bed of this environmentally sensitive area of the Forth. The ITT has the same operating restrictions as a bored tunnel although it may be constructed in approximately 5.5 years at a cost of between £3.51bn and £4.53bn and with a benefit to cost ratio of 2.85. Incorporating multi-modal options could be achieved by providing a widened tunnel section at a similar additional cost to a bored tunnel.
Presiding Officer, I would now like to turn to the comparative analysis of these options and their performance against the assessment criteria.
Summary of the comparative analysis
The environmental importance of the Forth has meant working closely with the statutory consultation authorities, Scottish Natural Heritage, Historic Scotland and SEPA over the summer to produce a Strategic Environmental Assessment (SEA). The SEA assesses the predicted effects of each of the options against a range of objectives relating to environmental quality, communities, health, the natural environmental and cultural heritage.
Based on this assessment, and the additional assessment which considers the EU Habitats Directive designated sites of the Forth, a bored tunnel performs best, the impacts associated with a bridge can be mitigated through careful design and working methodologies.
This assessment also found that an immersed tube tunnel has the greatest risk of impact to the protected environment of the Forth due to its method of construction. To determine the level of this risk would require a major investigation of the Forth, which may take a further year; time which is ill-afforded when considering the state of the existing Bridge.
The options for the crossing improve transport connections and the reliability of travel times. This will reduce the CO2 emissions relative to the base case of continuing to rely on the existing bridge.
I have already set out the restrictions which apply to goods being transported through a tunnel. Tunnels are subject to restrictions stemming from the international Carriage of Dangerous Cargoes by Road requirements set in place by a 2005 European Agreement. These class a series of hazardous goods as generally prohibited from road tunnels.
Whilst a bridge has restrictions related to its design, the existing Bridge carries some 200 special loads per annum and the day to day restrictions are much less than in a tunnel. All traffic can use a bridge, from pedestrians and cyclists through to the largest loads, whereas they cannot all use a tunnel. Assessing the options against the operating restrictions and operating risks criteria therefore means that bridges perform better than tunnels.
The Government also takes the view that decisions must be made now to provide the flexibility for multi-modal public transport measures to be incorporated into the crossing. The Government has taken the decision in principle to incorporate multi-modal public transport in its choice of option.
I have set out the cost estimates for the options already, but to recap, the estimates for each option in outturn prices including VAT and including multi-modal public transport are:
· Cable-stayed bridge £3.25 billion - £4.22 billion
· Suspension bridge £3.62 billion - £4.70 billion
· Bored Tunnel £5.12 billion - £6.60 billion
· Immersed tube tunnel £4.77 billion - £6.19 billionn
This clearly shows that against the cost criterion, the bored tunnel is the most expensive option and a cable stayed bridge the least. The benefit cost ratio and the Value for Money tests all indicate the cable-stayed bridge as the best performing option.
On cost risk, the risks associated with the options are related to the uncertainty associated with each. This has been reflected in the use of Optimism Bias in line with Treasury guidance.
In taking market soundings, there is greater concern that the costs of a tunnel may increase than those for a bridge. This is greater still where the tunnel is bored since ground conditions can only ever be fully understood as the tunnel progresses. There is more cost certainty for an ITT since the tunnel units themselves are manufactured in a controlled environment before being floated and lowered into place.
On time to construct, a cable stayed bridge or an immersed tube tunnel would take least time to construct, and a bored tunnel the most.
Preferred option
This consideration of each option against the assessment criteria has been endorsed by both Cabinet and an independent peer review carried out by international procurement and construction experts.
Having assessed all these factors the Government has come to the view that the Forth Replacement Crossing should be a cable-stayed bridge with multi-modal capacity on a route slightly to the west of the existing Road Bridge.
The replacement crossing is about more than just the crossing itself: the connections at either side are equally important. Providing a link to the M9 will allow greater choices and opportunities to West Lothian, whilst the construction of improved junctions in Fife will protect and promote access to the development areas of Fife. Including dedicated public transport will provide opportunities for those who travel into and around Edinburgh and offer improved opportunities for links more widely between Fife, Edinburgh and the Lothians.
The Forth crossing is a crucial part of the road network connecting communities on a local, regional and national scale and is overloaded due to single occupant cars during peak periods. This is only predicted to worsen in the future. Our key objectives of a wealthier and fairer and greener Scotland are well supported by this decision to protect cross-Forth travel whilst ensuring the flexibility and capacity to provide for other modes of transport including measures to ensure reliability of the crossing.
Next Steps
The new bridge will be the single largest transport project for a generation and we are determined that strong, clear governance is put in place to ensure the costs and risks are effectively managed and the project is delivered on time.
By the time it opens in around nine years' time the new bridge with a segregated public transport corridor will cost between £3.25bn and £4.22bn. Having taken the decision to build a bridge, work can now move forward on the legislative and procurement options for delivery: further announcements on the details of the bridge as well as the authorisation and procurement processes will be made during 2008. Work is continuing on the procurement options and this will include consideration of the appropriate transfer of risk to the private sector, in line with current government policy on the development of the Scottish Future Trust. The Government is against tolling.
The programme for the development of the project envisages a submission for authorisation in 2009, and a procurement competition in 2010 leading to an appointment of a constructor in 2011.
Transport Scotland will take this decision forward and have been procuring the services of a world-class consultant to develop the design of this new crossing. An announcement on the preferred bidder arising from this competition will be made shortly, and we look forward to confirming their appointment early in the new year to deliver the programme I have set out.
Conclusion
Presiding Officer, the new Forth Crossing is a hugely ambitious project. It will be the largest construction project in a generation in Scotland. It will be an iconic structure. It will maintain a fundamental link across the River Forth and incorporate the opportunity for a real change through multi-modal public transport provision. It will create a new and better connection to our transport infrastructure in West and East central Scotland. And it will be delivered through effective and comprehensive care for our natural environment.
The Forth Rail Bridge created an image of global significance when it was constructed in the 19th century. In the 21st century our vision of a new crossing of equal stature and significance is the Government's promise today.