2019_programme: UXO RISK MITIGATION FOR OFFSHORE WINDFARMS; A CASE STUDY FROM THREE DANISH WINDFARMS - RESULTS AND FUTURE CHALLENGES



  • Session: 07. Underwater Unexploded Ordnance (UXO) Detection and Remediation
    Organiser(s): Jans Wolfgang, Richardson Mike
  • Lecture: UXO RISK MITIGATION FOR OFFSHORE WINDFARMS; A CASE STUDY FROM THREE DANISH WINDFARMS - RESULTS AND FUTURE CHALLENGES
    Paper ID: 845
    Author(s): Erbs-Hansen Dorthe Reng
    Presenter: Erbs-Hansen Dorthe Reng
    Presentation type: oral
    Abstract: The potential for Unexploded Ordnance at offshore windfarm sites poses both safety and commercial risks to developers. To mitigate these risks, these sites are subject to extensive study and survey before the construction of the windfarm can commence.\n\nGeophysical surveys and inspections of potential UXOs (pUXO) were recently concluded for three Danish Offshore Windfarm (OWF) projects. The geophysical surveys comprised high resolution multibeam, side scan sonar measurements, and a magnetometer array providing full coverage of the relevant areas. \n\nThe data was processed and interpreted, resulting in a list of potential UXO targets which required further investigation. Detailed inspections were then performed with a total of 219 No. pUXO inspected. Of the 219 No. targets inspected, 4 No. were confirmed to be UXO, i.e. less than 2% of the inspected targets.\n\nOWF UXO inspection campaigns commonly result in a relatively low number of actual UXO finds, in fact the ratio of confirmed UXO to scrap/geology/’nothing found’ rarely exceeds 10%, even for highly contaminated sites. There are a number of reasons for this including geology, fishing activity, general vessel traffic and the survey spread or technique used. In addition, there exists various methods for processing and interpretation of the data acquired.\n\nIt will be discusses, how surveys can be optimized for a particular site and also explored, how processing and interpretation of data acquired may be improved to minimize the number of ‘false’ targets requiring detailed inspection. It will also be explored, how collaboration and knowledge sharing between industry, research and authorities can improve efficiency in clearance of sites for offshore developments.\n
  • Corresponding author: Dr Erbs-Hansen Dorthe Reng
    Affiliation: Vattenfall Vindkraft A/S
    Country: Denmark
    e-mail: