A study of wave climate and wave energy in Poole and Christchurch Bays

Abstract

There appear to be few wave recordings covering more than a relatively short period of time for coastal sites around the British Isles. This Thesis utilises the data from a Waverider Buoy located 800 m offshore in. 14 m of water in Poole Bay between June 1974 and March 1979. A detailed study of the wave climate has been undertaken in this previously unrecorded region.

At a coastal location the effects of wind direction are of major importance, Some new wind-wave diagrams and relationships have been established and have enabled the Weibull probability line to be corrected for extrapolating extreme events for an 'average' wind climate.

A cost effective digital recorder has been adapted for recording wave data sampled at half second intervals. A total of 17 wave parameters were calculated for each 20 minute recording period every 3 hours during a period of nearly one year. A comparison of similar parameters to those derived from simultaneously recorded analogue data was undertaken. Other wave parameters recorded in digital form have been related. Wave spectra have been derived and the build-up to a number of high sea state conditions has been examined.

An assessment of the available wave power at the Waverider Buoy site has been made during the years 1975 to 1977 inclusive. A line of wave power devices has been suggested in an arc in Poole and Christchurch Bays and possible effects on the shoreline have been discussed.

A computer wave refraction analysis has been undertaken in the Bays which has allowed wave orthogonals with any period and approach direction to be reproduced. A new method of verifying such wave refraction diagrams utilising recorded and observed wave data has been devised.

The wave refraction program has been extended to enable longshore wave energy flux to be calculated for a wave orthogonal reaching the shoreline from deep water. Using the CERC formula an assessment has been made of the quantities and directions of longshore drift in 2 km shoreline cells along the length of the Bays.

New values of the coefficient, k, in the CERC formula have been established for groyned beaches composed of sand or shingle, and a mixture of these materials.

More information

Identifiers

Catalogue record

Export record