This project has been put on hold indefinately but has been included here for historic information reference purposes only.




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Peterhead Bay Authority has engaged professional advisers to investigate how to reduce downtime in the port caused by sea swell entering the harbour. During periods of gales from a North-East to South-South-East direction, wave energy propagating through the harbour entrance can result in disruption to all port side operations. Peterhead Bay Harbour is vulnerable to sea swell during winter storms causing turbulence at the berths with the result that vessels have to evacuate an average six occasions per year. This causes disruption and delay to cargo handling operations and for certain trades creates a safety uncertainty which has resulted in the port being unable to diversify into other sectors. Delivery of a safe port environment is a necessary step towards securing a viable future for the post oil and gas period. It was to provide a long-term solution to these problems that the Peterhead Bay Calming Project was instigated.

The lead consulting engineers for the project are Peter Fraenkel Maritime based in Dorking, Surrey. The firm was selected because of its extensive experience in marine works around the world and previous involvement with projects in the port. 

Background

Initial work on this project commenced in 1998 with the target of eliminating the problems encountered in the port caused by sea swell disrupting marine and cargo handling operations. This is the largest project ever contemplated by the Authority, with an estimated cost of £22 million. Significant hurdles remain to be overcome if the project is to proceed. Extensive research and development studies are continuing. During the past year wave modelling, an Environmental Impact Assessment, vessel navigation simulation and consultation exercise have been completed. Following on from this preliminary work, detailed engineering design commenced to produce an optimised design of the proposed breakwater in terms of effectiveness, impact on navigation and cost. 

Further studies including 2 dimensional flume tank and 3 dimensional wave basis testing are being undertaken in Denmark and a marine borehole investigation to evaluate seabed conditions is also underway. These studies will be completed by later summer 2002 and it is hoped that the project can be put out to tender in October 2002. In compliance with the Utilities Contracts Regulations 1996, adverts have been placed in the European Union Official Journal seeking firms interested in tendering for either the construction works or consulting engineers site supervision services to complete a pre-qualification questionnaire. Negotiations and discussion are continuing with statutory bodies to obtain the necessary consents and licences to proceed.

Project Benefits

The project target is to reduce swell entering the port to the extent that the number of occasions when there were no berths at which a vessel can safely lie is reduced to an average of once every ten years. Further studies are ongoing to further extend the operational capability of the port up to the one in 50 year storm, through modifications to the fender and mooring arrangements. This will provide a number of benefits to the port and surrounding businesses, including:-

- The creation of a suitable environment for increasing the volume and range of marine trade through the port

- Reducing coastal erosion

- Providing protection for existing structures

- Creating the potential for development of additional quays and infrastructure working areas within the harbour.

- Restoring confidence with the offshore rig repair and refurbishment operators.

Development Option

Extensive engineering studies have been carried out to determine the causes of adverse wave conditions which can arise from time to time at berths within the harbour. Studies have also been carried out to identify possible works to alleviate the problems. As a result of these studies, it has been established that the most effective solution will be to construct a new breakwater. This will extend outwards from the wall of the existing North Breakwater beyond the entrance to the harbour in a generally southerly direction. The new breakwater will substantially reduce the amount of wave energy which can enter the bay. The layout proposed is such as to maintain a clear passage for navigation of vessels into and out of the harbour while achieving its primary objective of reducing wave heights at the berths.

The new breakwater will be constructed as a rock mound probably using locally quarried stone and with the side and end slopes of the mound armoured with concrete units weighing up to 40 tonne. It will extend for around 195 metres in water depths of between 20 and 22m below chart datum. The total weight of rock and other materials in the breakwater will be around 750,000 tonnes. Construction will ideally start in spring and extend over two summer seasons. It is likely that a combination of floating and land-based plant will be used to build the breakwater. 

The optimum breakwater layout was determined after extensive tests on a 1 to 100 scale model of the harbour at HR Wallingford's testing laboratories. This demonstrated the improvement in wave conditions which will be obtained at various berths around the bay. Detailed design of the mound cross section will also involve physical model testing of the breakwater which will be carried out in a three-dimensional wave flume. The breakwater will be designed for a life of at least 100 years and for armour stability in once in 200 year storms.

The costs for the studies so far are around £850,000 and include preliminary investigations, site survey, wave modeling, environmental impact assessment, cost benefit analysis, consultation, navigation studies and 2D flume testing.

While striving to provide the safest commercially attractive facilities within the Bay Harbour is a statutory duty of Board members they are critically aware of the finite nature of fossil fuels and the need to provide for future customers' requirements. At present vessels can operate in a restricted capacity during the winter and the benefits of a 24 hour/365 day safe berthage as provided at neighbouring ports has become the primary objective. Furthermore, it may be financially prudent to take advantage of buoyant market conditions to launch this important project at this time.