CHOOSING
A SEDIMENT CURTAIN
It has been Australian Boom and
Baffles experience over 30 years of designing,
manufacturing and installing sediment and turbidity
curtains that application failure or ineffectiveness is
usually a consequence of a number of factors the
principle one being that the product has been
underspecified usually to achieve project budget
requirements or alternatively there has been a high
performance specification with inadequate provision made
in the project budget to achieve it. Over recent years
there has been a growing focus on the environment to the
extent where inadequate turbidity plume management can
result in significant project delays, a greater focus on
project environmental management resulting in more
prescriptive requirements from regulators and in some
cases prosecution for non-compliance all of these can
have a significant impact on the overall profitability
of a project for the contractor.
Whilst there are increased
pressures on the contractor the latter has also to be
realistic in the expectation of the effectiveness of the
sediment curtain. It is Australian Boom and Baffle Co
policy to advise a client if their expectation of
effectiveness is unrealistic and if there is a need to
reassess with the regulator the configuration of the
specified systems. On a number of occasions this
has resulted in the development of systems which have
been as effective a practically possible given the:
 | environmental conditions
experienced at the deployment location including:
currents, wind, waves and sea conditions |
| the type and nature of suspended
solids generated |
| the most appropriate plume
management objective ie limit visual pluming then
slow velocity of subsurface plume such that
suspended solids remaining drop out of the water
column a short distance from the curtain |
We have found that early assistance
by Australian Boom and Baffle in project planning,
system design and installation together with
consultation with regulators has resulted in effective,
durable and fit for purpose products being installed
that have no delays to projects.
Notwithstanding the above there
have been recent occasions where we have designed and
specified system which have not been chosen by the
contractor on a cost basis only to have to be engaged at
as later date to undertake remedial action following
project shutdown due to installed systems failure.
To avoid the above it is of
critical importance that as much information about a
project be provided, including but not limited to the
following:
| prevailing environmental
conditions including currents,
tidal streams, wind, waves and sea conditions |
| extremes of the above and design
parameters if the installation is to be effective in
those conditions |
| water volumes to be impounded
within the curtain and the tidal flow duration for
both ebb and flood |
| bottom type for anchoring
systems |
| durability considerations in
relation to weather, wave, vessel impact and debris |
| proximity of shipping and
special considerations for anchoring systems |
| the type and nature of suspended
solids generated |
| the most appropriate plume
management objective ie limit visual pluming then
slow velocity of subsurface plume such that
suspended solids remaining drop out of the water
column a short distance from the curtain |
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