Tidal asymmetry in creeks surrounded by saltflats and mangroves with small swamp slopes
Aucan, Jerome, and Ridd, Peter V. (2000) Tidal asymmetry in creeks surrounded by saltflats and mangroves with small swamp slopes. Wetlands Ecology and Management, 8 (4). pp. 223-232.
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Most mangrove swamp/salt flat systems have tidal currents that are ebb dominated, however, some systems show only slight ebb dominance despite having a very large swamp volume relative to the creek volume. Cocoa Ck in northern Australia is such a system. Results are presented from a simple analytical model for flow in Cocoa creek together with detailed water level observations in the swamps. It was found that the primary factor reducing the ebb dominance of this system was the very low slope of the swamp surface. During rising tides, water floods as sheet flow; however, on ebb tides, the surface water slope in the swamp becomes greater than the swamp surface slope, with the result that areas of swamp closest to the main feeder creek (Cocoa Ck) dry before areas furthest from the creek. Thus, about an hour after ebb tide commences, there is a large quantity of water perched on the salt flats/mangroves, tens of centimetres higher than the water in the creek. This water cannot leave the swamp via sheet flow, but must leave through a very small and shallow creek which is also highly constricted by vegetation. This effectively increases the friction on ebb tides and results in a delay in water leaving the swamps and salt flats, reducing any tendency towards ebb dominance.
|Item Type:||Article (Refereed Research - C1)|
|Keywords:||hydrodynamics; mangroves; salt flat; tidal currents|
|Date Deposited:||03 Jul 2012 03:31|
|FoR Codes:||04 EARTH SCIENCES > 0405 Oceanography > 040599 Oceanography not elsewhere classified @ 51%
04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology @ 49%
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 51%
96 ENVIRONMENT > 9699 Other Environment > 969999 Environment not elsewhere classified @ 49%