Observation and Analysis of Hydrodynamic Parameters in Tidal Inlets in a Predominantly Semidiurnal Regime

Abstract

Gold Coast Seaway and Jumpinpin Bar are two tidal inlets that connect the Pacific Ocean to the extensive Gold Coast estuarine system. While the Gold Coast Seaway has been stabilized in the mid-1980s by two rock walls, Jumpinpin Bar has remained a highly dynamic tidal inlet. A detailed study of these two tidal inlets is overdue and has been hindered for a long time by the lack of comprehensive field data. This study provides an extensive hydrodynamic data set, which on one side provides an insight into the hydrodynamic behavior of these two tidal inlets and on another side provides a base for their further study. The measured data show relatively high flow velocities at both locations exceeding 2 m/s. It also shows a strong spatial asymmetry in flow velocity distribution across the Gold Coast Seaway during the ebb tide, which accounts for some of the morphological changes at the study area. A five-month waterlevel measurement indicates a mixed, predominantly semidiurnal tidal regime at these tidal inlets. Examination of tidal variation shows minor temporal tidal asymmetry at both inlets with potential impact on the sediment transport regime at the inlets. In terms of stability, investigation into the tidal prism and cross-sectional area relationship for both inlets can be described using existing relationships obtained from regression analysis of tidal inlets on Pacific and Atlantic coasts. In regards to stability analysis based on tidal prism-littoral drift relationship, the Gold Coast Seaway seems to be approaching stability while Jumpinpin Bar seems to be more of a dynamic inlet.

Short-Term Variability of Nutrients and Fecal Indicator Bacteria within the Gold Coast Seaway, Southern Moreton Bay (Australia)

“…Tidal flows through the Seaway into the Broadwater range from 10 to 40 3 10 6 L (Moss and Cox, 1999), resulting in a very strong flushing effect within the shallow Broadwater. A detailed description of the tidal regime and hydrological characters of the Seaway is presented by Sennes et al (2007) and Mirfenderesk and Tomlinson (2008). Freshwater primarily enters the Broadwater via the Nerang, Coomera (north and south arms), and Pimpama Rivers, which is of lesser magnitude than tidal inputs, except after periods of heavy rain (Moss and Cox, 1999).…”

“…The southern connection between the Broadwater and the Pacific Ocean is through a man-made navigation channel, the Gold Coast Seaway. The Seaway plays an important role in the ecological health of the intertidal waters of the region, because it influences the exchange of oceanic waters, sediments, organic matter, nutrients, and trace metals between the Broadwater and the Pacific Ocean (Mirfenderesk and Tomlinson, 2008).…”

Asymmetric tide in Lake Vallunden (Spitsbergen)

“…If the duration of the decreasing tide is shorter than that of the increasing tide (and consequently, the ebb currents exceed the flood currents), the tide is referred to as ebb dominant (Walton, 2002). Usually, asymmetric tide is developed in channels and inlets (Hoitink et al, 2003;Mirfendersk and Tomlinson, 2008). This phenomenon is analyzed in many papers (Gallagher, 1973;Aubrey and Speer, 1985).…”

Flood-tide Delta Morphological Change at the Gippsland Lakes Artificial Entrance, Australia (1889–2009)

“…groynes and/or training walls), and navigability may be best maintained by regular dredging and littoral sand bypassing. As a result of these reconfigurations, the dynamic balances between environmental parameters may change in ways that provoke significant morphological responses (see, for example, Bird & Lennon 1989;van Rijn 2004;Powell et al 1996;Longdill & Healy 2007;Mirfenderesk & Tomlinson 2008). At the artificial entrance to the Gippsland Lakes (an extensive coastal lagoon system covering 400 km 2 ) located in Victoria, Australia (see Figure 1), an artificial entrance was constructed between 1870 and 1889 to provide maritime traders access to and from Bass Strait.…”