Stokes, C., Beaumont, E., Russell, P., Greaves, D., 2014. Coastal Impacts of Marine Renewables: Perception of Breaker Characteristics by Beach Water Users. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 389–394, ISSN 0749-0208.

Beach water users such as bathers and surfers are of economic importance to tourism in Cornwall, UK. Wave energy converters soon to be trialed at the ‘Wave Hub’ marine renewables test site in Cornwall, may reduce inshore wave heights and have an unknown effect on wave period, therefore potentially affecting water recreation and tourism on the beaches in its lee. There is little existing research to indicate what surf conditions are ‘preferred’ by various beach water user groups, and how they perceive different wave conditions has never been investigated. Without an understanding of how waves are observed and described by water users, little can be said about how likely they are to be affected by, or if they will correctly perceive, any changes to inshore waves caused by Wave Hub or future renewables projects. To investigate how waves are perceived, nearshore wave buoy measurements collected in 10 m water depth and transformed to breaking height, were compared to concurrent visual observations of mean breaker height and period made by 354 participants. Ratios of observed over measured height and period were used to quantify the perceptions. The vast majority of water users underestimated significant wave height and period at breaking, and their average perceptions can be approximated by H_vis ≈ 0.70H_b and T_vis ≈ 0.83T_1/3 (for waves 0.5≤H_b≤ 3.5 m and 3 ≤T_1/3 ≤ 15 s). Although perceptions were highly varied, average perceptions did not change significantly under different wave conditions. Perception of wave period did not change significantly between the different water user groups considered. Expert water users and surfers generally under predicted wave height the most, especially for small and/or short period waves, while novices and non-surfing water users made height observations closer to measurements.