Requirements for monitoring environmental impact of seafloor cables: issues and answers

Governmental permitting agencies and Non-Governmental Organizations have expressed increasing concerns about the environmental impacts of seafloor cable systems, both short-term and long term. As a result, increasingly restrictive and costly conditions are being imposed in the permitting process. These requirements affect cable routing options, restrict installation methods and impose substantial requirements to verify the installation condition and to monitor the cable and local environmental impact over periods of many years. The results are increased times to "ready for service" and increased costs for installation and maintenance of undersea cable systems. All of these requirements are costly and time-consuming to cable installers and owners, both commercial and military. In addition, very few of the requirements can be clearly justified at the technical level. Even fewer have obviously justifiable scientific bases. While it is certainly desirable to minimize environmental impact, it also is important to do so in the most economic and legally credible way possible. This paper: a) Describes the kinds of requirements being imposed by various state and local permitting agencies b) Outlines the technical issues associated with interpreting and complying with those requirements, including both general issues and some specific local examples c) Compares the impacts of cable operations (particularly burial) to the effects bottom trawling d) Outlines some general approaches to help resolve the issues, including a technical review of the likely scientific basis for relating cable operations to environmental impact and an analysis of practical measurement methodologies e) Suggests a series of actions that can be taken by the industry to provide a scientific basis for environmental assessments and mitigation requirements, for submarine cable projects.