UXO Desk Study -Unexploded Ordnance- Hollandse Kust (west) Wind Farm Zone RVO.nl distribution Document title: UXO Desk Study – Unexploded Ordnance Document subtitle: Site Data Hollandse Kust (west) Wind Farm Zone (HKWWFZ) Author (s): REASeuro Contract manager RVO.nl: Matté Brijder Project ID RVO.nl: WOZ2180092 Number of pages: 152 pages Version Approved for public disclosure Approved for public disclosure by by contract manager RVO.nl project manager offshore wind RVO.nl Name Matté Brijder Name Ruud de Bruijne Final Signature Signature Date Date 13-8-2018 2018-08-13 1 van 1 UXO Desk Study Unexploded Ordnance Site Data Hollandse Kust (west) Wind Farm Zone (HKWWFZ) 73065 / RO-180140 version 3.0 August 7th , 2018 Riel Explosive Advice & Services B.V. Alphenseweg 4a 5133NE5133 NE Riel Riel NederlandNederland PostbusPostbus 2121 5133 ZG Riel Nederland T +31 (0)13518 60 518 76 60 F 76 +31 F 518 +31 60 (0)13 77 518 www.reaseuro.com 60 77 www.reaseuro.com [email protected] KvK-nummer 180.501.31 BTW-nummer NL80.67.88.136.B01 TABLE OF CONTENTS Page SUMMARY ..................................................................................................................................................... 6 SAMENVATTING ....................................................................................................................................... 9 1 GENERAL INFORMATION .................................................................................................................. 12 1.1 MOTIVE ........................................................................................................................................................................... 12 1.2 AREA OF INVESTIGATION ............................................................................................................................................... 12 1.3 PURPOSE AND MAIN OBJECTIVES ................................................................................................................................. 13 1.4 STRUCTURE OF THE REPORT .......................................................................................................................................... 13 1.5 GLOSSARY OF TERMS ..................................................................................................................................................... 15 2 APPRAISAL OF HISTORICAL SOURCES ............................................................................................ 18 2.1 SOURCES ......................................................................................................................................................................... 18 2.2 WAR RELATED EVENTS RELEVANT FOR THE AREA OF INVESTIGATION ....................................................................... 19 3 WAR RELATED EVENTS ...................................................................................................................... 20 3.1 NAVAL MINES ................................................................................................................................................................. 20 3.1.1 World War I: German minefields ............................................................................................................... 20 3.1.2 World War II: German minelaying ............................................................................................................ 21 3.1.3 World War II: British minelaying ................................................................................................................ 23 3.1.4 Post-war mine clearance .............................................................................................................................. 24 3.1.5 Conclusion on naval mines.......................................................................................................................... 26 3.2 AERIAL WARFARE ........................................................................................................................................................... 27 3.2.1 Flight paths of allied bomb raids .............................................................................................................. 27 3.2.2 Aerial attacks on ships and convoys ........................................................................................................ 29 3.2.3 Conclusion on Aerial Warfare ..................................................................................................................... 32 3.3 NAVAL WARFARE ........................................................................................................................................................... 33 3.4 GERMAN SHOOTING AREA ............................................................................................................................................ 33 3.5 WRECKS OF AIRCRAFT AND VESSELS ........................................................................................................................... 34 4 GAPS IN KNOWLEDGE AND UXO RISK AREA ................................................................................. 35 4.1 GAPS IN KNOWLEDGE .................................................................................................................................................... 35 4.2 MAPPING THE WAR RELATED EVENTS .......................................................................................................................... 35 4.3 UXO RISK AREA .............................................................................................................................................................. 35 4.3.1 Defining the UXO Risk Area ........................................................................................................................ 35 4.3.2 Condition of expected UXO ........................................................................................................................ 37 5 UXO BURIAL ASSESSMENT ............................................................................................................... 40 5.1 SCOUR ............................................................................................................................................................................. 40 5.2 BED FORM MIGRATION .................................................................................................................................................. 41 5.3 CONCLUSIONS ................................................................................................................................................................ 43 6 UXO MIGRATION ASSESSMENT ....................................................................................................... 44 6.1 MIGRATION BY NATURAL CAUSES ................................................................................................................................ 44 6.1.1 Hydrodynamics ................................................................................................................................................ 44 6.1.2 Morphodynamic behaviour ......................................................................................................................... 44 6.2 MIGRATION DUE TO HUMAN ACTIVITY ........................................................................................................................ 45 73065 / RO-180140 version 3.0 Final report Page 2 of 150 Hollandse Kust (west) Wind Farm Zone 6.3 MAXIMUM PERMISABLE SAFE TIME INTERVAL ............................................................................................................. 45 7 HAZARDS OF UXO LIKELY TO BE ENCOUNTERD ........................................................................... 47 7.1 AERIAL BOMBS ................................................................................................................................................................ 47 7.2 DEPTH CHARGES ............................................................................................................................................................. 48 7.3 TORPEDOES ..................................................................................................................................................................... 48 7.4 NAVAL MINES ................................................................................................................................................................. 48 7.4.1 Contact mines ................................................................................................................................................... 49 7.4.2 Influence mines ................................................................................................................................................ 49 7.5 ARTILLERY SHELLS ........................................................................................................................................................... 49 7.6 ANTI-HANDLING DEVICES ............................................................................................................................................. 50 7.7 SELF-DESTRUCTION DEVICES ......................................................................................................................................... 50 8 EFFECTS OF DETONATIONS............................................................................................................... 51 8.1 EFFECTS OF UNDER