Abstract
This research has been to establish possible shoreline effects due to the future exploitation of marine renewable wave energy. The distance from shore, operational regime and the variability in the annual downstream shadow effect are key requirements to enable predictions of possible ecological effects on the shoreline. The accepted method of estimating the amount of shoreline wave action or ‘exposure’ to which the rocky shore is subject has been to use quantitative ecological surveys and indicator species vertical range. Difficulties can occur when natural and anthropogenic disturbances have a significant influence on these particular species, fundamentally altering the community structure and spatial distribution, which can result indifferent assemblages evident even though subject to comparatively similar levels of wave action.
To overcome these limitations a new efficient and cost effective device is presented that is able to measure an average quantitative level of wave action over weeks and/or months at the relevant spatial scale of rocky shore biota. This new device will not only enable specific biotopes to be studied in relation to an objective proxy measurement of wave action over biologically meaningful timescales but could also be used, with bathymetry data, for economical evaluations of near-shore wave energy resources in developing nations.
Long term monitoring data from Orkney are presented which shows good correlations of significant wave height and direction from concurrent wave buoy data at the European Marine Energy Centre wave test site. Initial measurements have found that habitat and biotope classifications currently used to underpin European protected areas have an over simplistic classification of wave energy levels needed for both accurate comparisons and impact determination between certain rocky shore biotopes. Equivalent rocky shore biotopes classed within the same level of energy are observed to have similar levels during the summer but are subjected to a difference in the ratio of wave action of up 1:2 in winter.
Acknowledgement: This article was identified by the Crown Estate Wave and Tidal Knowledge Network