Update to C634 Accelerated Low Water Corrosion (ALWC) (P2951)

In the early 1990s UK port operators noticed an alarming acceleration in the rate at which steel structures such as harbour walls and jetties were deteriorating - sometimes up to 25 times faster than normally expected. The phenomenon which became known as “accelerated low water corrosion” (ALWC) was caused by bacteria that were thriving on steel surfaces around low water. More than 90% of UK ports were estimated to be afflicted by the phenomenon, resulting in significant repair costs and operational problems.

CIRIA report C634 was written for CIRIA in 2005 by a consortium led by Mott MacDonald with BAC Corrosion Control Ltd, Nuttall John Martin and the University of Manchester. The publication provided a comprehensive guide to the management, condition appraisal, repair, protection and monitoring of ALWC.

Over the past ten years, understanding of ALWC has grown, as have measures for its prevention and treatment and, of course, experience in dealing with the problem including:
  • A better understanding of the scale of the problem
  • Technical developments in terms of coatings and new grades of steel
  • Emerging environmental concerns relating to protection systems
  • New forms of procurement and resulting operating responsibilities
  • Terminology – particularly the wider consideration of “microbial-induced corrosion”
CIRIA is considering producing a supplement or an update to the guide, and would welcome your feedback.

Figure 1 & 2: G Maden, Mott MacDonald


This survey will take no longer than 10 minutes to complete. Take the survey.

Related guidance
Briefing: Management of accelerated low water corrosion in steel maritime structures”, CIRIA Guide C634, 2005 – Recent developments