[Coral-List] coral sedimentation thresholds for dredge induced sedimentation
Jeremy J. Sofonia
jeremy at sofonia.com
Sat Jan 27 21:47:19 EST 2007
Wanted to add:
Also important in estimating potential impacts to benthic primary
producers is the type of dredge (e.g. cutter suction, trailer hopper,
etc.), the size of the dredge (m^3), it's power, it's proximity to
sensitive resources (such as corals), and the duration/ frequency
they are operating. Other operational details such as of 'side-
casting' and 'overflow' rates can also have significant effects
(positive or negative). Obviously spoil disposal locations and
methods should also considered, but keeping in mind that sediments
released during disposal will behave differently than those suspended
during cutting (i.e. less fines).
If the program is to run in a working port facility, you'll want to
look at how local conditions are affected by ongoing operations such
as berthing and other vessel movements (e.g. tugs can kick up a fair
bit of sediment/ turbidity in shallow areas). Contamination such as
TBT or heavy metals is not uncommon and proper disposal of these
materials also requires some forethought.
Potential impacts to whales and other cetacens, as well as marine
turtles should also be investigated. These can be both direct (e.g.
physical impact) and indirect (e.g. acoustic, lighting). Seasonal
timing of operations is therefore a key avoidance/ minimization measure.
Certainly a lot to think about, but with early (and regular)
consultation with your environmental authorities, clear communication
with the proponent, and some good science, the successful management
of these types of programs is certainly possible.
Hope this was of some help,
JEREMY J. SOFONIA
Senior Marine & Environmental Consultant
SKM Australia Pty. Ltd.
7th Floor, Durack Centre
263 Adelaide Terrace
Perth, WA 6000
On 24/01/2007, at 5:43 PM, Andrew_Jamieson at URSCorp.com wrote:
> Dear Coral Listers
> I am trying to track down any research undertaken into tropical coral
> sedimentation thresholds for dredge induced sedimentation - can anyone
> direct me in the right direction ?
> Many thanks
> Andrew Jamieson
> Senior Environmental Scientist
> andrew_jamieson at urscorp.com
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
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