Hydrography and photommetry : tools for artificial surfing reef studies?
Scarfe, Bradley Edward
Constructing hard rock structures traditionally has controlled coastal erosion but they have negative visual appeal. Much research over recent years has gone into developing artificial surfing reefs as an aesthetically pleasing form of coastal protection with additional recreational benefits. This paper has consolidated previous research on the important wave parameters for recreational surfing in the context of artificial surfing reef studies. The important parameters are breaker type, breaking wave height, offshore seabed gradient, wave peel angle, wave peel rate and wave plunge distance. In addition, wave height transformation during breaking is introduced as an important consideration for reef design. Bathymetry is identified as the largest influence on these parameters. Numerical modelling has been used to design reefs by researchers. Models must be validated with empirical observations to ensure the reefs form surf as designed. New RTK GPS hydrographic and zoom-in video photogrammetric systems are presented as tools to validate these models. The RTK GPS hydrographic system consists of two Trimble MS750 receivers capable of low latency 20Hz observations, a depth sounder and HYDROpro software. Tests show that the MS750 receivers are consistent with manufacturers claims that they are capable of providing single axis heave compensation. An RTK GPS tidal correction is also manually calculated. The photogrammetric system is made up of two off-the-shelf video cameras that are capable of measuring peel angle, peel rate and wave height changes during breaking. Initial tests show that this system can measure 3D wave coordinates with sub meter accuracy. Further testing is required to improve accuracy.
Degree Name: Bachelor of Surveying with Honours
Degree Discipline: Surveying
Publisher: University of Otago
Research Type: Dissertation
xi, 104 leaves,  leaves of plates :ill., maps (some folded) ; 30 cm. Includes bibliographic references. University of Otago department : Surveying. Cover title. "November 1999."