Low-cost investigation of wave dynamics across low energy reef environments in Indonesia

Abstract

The interaction between offshore waves and complex reef bottom profiles determines the hydrodynamic processes within the reef beaches, for instance, Sea-Swell (SS) wave dissipation, Infragravity (IG) wave generation as well as wave-induced currents and setups. These hydrodynamics phenomena are important to several ecological processes and control the associated shoreline erosion and flooding. Hence, a good understanding of the dynamics is needed that wave observations are challenging and expensive otherwise. Here we present a short term (12 hours) investigation of non-directional spectral waves using a series of HOBO pressure sensors. Six pressure sensors were deployed at 3 locations along the fringing reefs of Tunda Island, Banten Province - Indonesia. The wave spectra were estimated from the surface water fluctuations using linear wave theory for each hourly burst data. During observation, the Tunda waters were calm with significant wave heights were less than 10 cm with peak wave periods of 1/412 s at all sites. Despite the short period measurement due to memory issue, the result demonstrated the ability of HOBO pressure sensors to measure non-directional wave spectra at shallow water.