In July 2011, through the EU JASPERS program of technical assistance to Malta,Transport Malta obtained the services of Mott MacDonald to carry out a preliminary analysis of road tunnel link options between Malta and Gozo.
The purpose of the five month study was to provide a list of technical, engineering, environmental and economic issues relating to potential sub-sea tunnel fixed-link options connecting Malta and Gozo. The study presents a high level analysis of different tunnel options based on existing data, studies, information, site visits and various discussions with stakeholders.
The final report:
Presents a background review and a list of key issues identified during consultation with the various stakeholders;
Provides a broad economic assessment of introducing a fixed link between Malta and Gozo;
Identifies four potential tunnel alignments for further investigation;
Presents a high level environmental assessment of each of the four tunnel route alignments.
The number of vehicles crossing between Malta and Gozo has increased at 4.1% per annum between 2000 and 2010. In 2010, there were an average of 1,500 vehicles per day /direction and 5,500 people per day/ direction travelling between Malta and Gozo.
The introduction of a fixed link would reduce average journey times between Gozo and Malta by at least 40 minutes. Four potential tunnels alignments have been assessed at a preliminary, conceptual level ranging in length between 6 and 10 kilometres depending on their depth and structural design. The four tunnel alignment options take into account the engineering and environmental constraints that consultants were able to identify using existing data and information.
A detailed geological and geotechnical investigation is still required to determine more precisely the tunnel alignment, tunnel form, cost and construction methodology. The location, geology and characteristics of the project (contractual, economic, market conditions, regulatory requirements, working practices and local environmental conditions) can have a significant effect on the cost of the tunnel. In this respect, the consultants have estimated costs for the construction of the four different tunnel option alignments based on a case history review of different tunnel types around the world.
Based on the reviewed case studies, the range of costs (in 2010 prices) estimated for the construction of the fixed link is wide and would depend on ground conditions and other circumstances. The consultants have estimated a range of costs for each tunnel alignment option between €156m for a single-bore 3-lane bi-directional tunnel right up to €1080m for a twin-bore 2-lane uni-directional tunnel. The cost estimate for each option would need detailed verification following details studies of the short-listed options and would be subject to detailed reviews of economic and environmental considerations.
The Consultants found that:
With regard to the overall length, depth, configuration and size of tunnels an undersea tunnel link between Malta and Gozo would be technically feasible and does not exceed the capability of modern technology;
The geology of the area is potentially complex and not well documented. A detailed geological and geotechnical investigation is required to determine the optimum tunnel alignment, construction methodology and more detailed estimates of construction costs;
The typical construction stage for a tunnel of this nature would be approximately 5 to 7 years, but this average duration is strongly dependant on the geological environment;
A road tunnel link between Malta and Gozo could potentially be co-financed by the European Union under the Cohesion Fund;
The securing of external financing for the construction of a fixed link between Malta and Gozo would require a full feasibility study. Consultants advise that no external funding would be considered without a comparative assessment of other options to verify what is the most economically and environmentally advantageous way to link the islands. The full feasibility study and environmental impact assessments would also be required to assess the following different Malta-Gozo transport options:
Bridge and/or viaduct;
Bored and/or immersed tube tunnel;
Combinations (e.g. bridge and tunnel);
Other fixed links (e.g. combined/tidal barrage; railway; etc.);
Retention of existing ferry service and/or its service expansion;
Other transport services (air, sea);
Other measures (demand management, travel behavior change and similar).
A full feasibility shall require among other things detailed geological and geo-technical investigations including full geological mapping, geophysical investigations and core drilling, detailed designs, environment impact and risk assessments.
A presentation is available here (pdf, 2012, 691kb)
The report by Mott MacDonald is available here (pdf, 2012, 13.1Mb)
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