Page 229 - Alderney Regional Environmental Assessment of Renewable Energy: Environmental Report

Alderney Regional Environmental Assessment of Renewable Energy:
Environmental Report
ƒ Changes to risk management and emergency response (Section 7.3.2.11); and
ƒ Cable route risk in respect of vessel anchoring, burial depth and cable protection
(Section 7.3.2.12).
In this strategic study it has not been possible to consider each sea area or navigation channel
individually and therefore project specific investigations will be required prior to any individual
development taking place. It is recommended that developments are subject to a Navigational
Risk Assessment (NRA), carried out in accordance with industry standards. Within UK waters,
the following publications are used to define the methodology and output from NRAs:
ƒ Department for Transport - Guidance On The Assessment Of The Impact -
Methodology for Assessing the Marine Navigational Safety Risks of Offshore Wind
Farms;
ƒ Maritime and Coastguard Marine Guidance Note 371 ‘Offshore Renewable Energy
Installations (OREIs) - Guidance on UK Navigational Practice, Safety and Emergency
Response Issues’;
ƒ Maritime and Coastguard Marine Guidance Note 372 ‘Offshore Renewable Energy
Installations (OREIs): Guidance to Mariners Operating in the Vicinity of UK OREIs’;
and
ƒ IALA Recommendation ‘O-139’ On The Marking of Man-Made Offshore Structures
Edition 1, December 2008.
Commercial shipping is a key activity in Alderney and its territorial waters. Throughout this
assessment importance is considered to be low to moderate based on the RYA Medium route
connecting England and Alderney and the type of vessels using the harbours (for example
Braye Harbour accommodates some passenger ferries and freight vessels, small tankers and
relatively small cruise ships).
7.3.2.1 Collision risk
The survey, construction, operation and decommissioning of tidal stream turbines, cable
routing and offshore substations has the potential to increase the collision risk of vessels.
Collision risk has not been quantified within this assessment as specific development locations
and configuration are required to make a meaningful assessment; furthermore this type of
assessment is more appropriate at project level. Therefore the consequences of a collision
have been considered at a regional scale including the effects on commercial shipping and
recreational craft. This assessment assumes developers will complete a NRA to support
individual projects, and that these assessments will ensure developments are not sited in high
risk locations where effective mitigation cannot be applied. As a general statement, a higher
density of traffic provides a greater potential for collision risk. Bailiwick waters to the West of
Alderney are located within the ITZ, which controls and reduces the movement of transitory
vessels. Bailiwick waters to the East of Alderney overlap with vessel transit routes through the
Alderney Race. Throughout this assessment sensitivity is considered to be low to moderate.
This takes account of the sensitivity of vessels during adverse weather conditions and in
periods of peak tidal flow, with smaller vessels less able to manoeuvre against environmental
conditions (predominantly recreational craft and small fishing vessels). The presence of slow
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