Water and fine sediment dynamics in transient river plumes in a small, reef-fringed bay, Guam
Wolanski, Eric, Richmond, Robert H., Davis, Gerald, and Bonito, Victor (2003) Water and fine sediment dynamics in transient river plumes in a small, reef-fringed bay, Guam. Estuarine, Coastal and Shelf Science , 56 (5-6). pp. 1029-1040.
|PDF - Repository staff only - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader|
View at Publisher Website: http://dx.doi.org/10.1016/S0272-7714(02)...
Fouha Bay is a 400-m-long funnel-shaped, 10-m-deep, coral-fringed embayment on the southwest coast of Guam. It drains a small catchment area (5 km2) of steeply sloping, highly erodible lateritic soils. River floods are short-lived and the sediment load is very large, with suspended sediment concentration (SSC) exceeding 1000 mg l−1. The resulting river plume is about 1 m thick and is pulsing in a series of 1–2 h-long events, with outflow velocity peaking at 0.05 m s−1. Turbulent entrainment results in an oceanic inflow at depth into the bay. As soon as river flow stops, the plume floats passively and takes 5 days to be flushed out of Fouha Bay. The suspended fine sediment flocculates in 5 min and aggregates on ambient transparent exopolymer particles to form muddy marine snow flocs. In calm weather, about 75% of the riverine mud settles out of the river plume into the underlying oceanic water where it forms a transient nepheloid layer. This mud ultimately settles and is trapped in Fouha Bay. Under typhoon-driven, swell waves, the surface plume is at least 7 m thick and bottom entrainment of mud results in SSC exceeding 1000 mg l−1 for several days. It is suggested that successful management of fringing coral reefs adjacent to volcanic islands may not be possible without proper land use management in the surrounding catchment.
|Item Type:||Article (Refereed Research - C1)|
|Keywords:||river plume; fine sediment; flocculation; sedimentation; muddy marine snow; coral; Guam|
|Deposited On:||07 Jul 2009 12:15|
|Last Modified:||20 Jun 2013 00:43|
Last 12 Months: 0
|Citation Counts with External Providers:||Web of Science: 24|
Repository Staff Only: item control page