Environmental Science & Engineering - www.esemag.com - July 2005
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Floating silt curtain protects
North Saskatchewan River
By Chang Park
Due to congestion in the rapidly
expanding City of Edmonton,
Alberta, a new freeway is
under construction to handle
the increase in traffic. There are three
new water crossings on the east-west
section of the freeway, one of which is
the North Saskatchewan River.
The Care of Water section of the
specifications required a floating silt
curtain to contain any silt and sediment
released during construction close to
the river bank. With the recent expansion
in the number of staff of the
Canadian Federal Department of
Fisheries and Oceans (DFO), they have
taken over direct responsibilities for
enforcing The Fisheries Act from local
provincial departments of the environment.
A permit is required from the
Department of Fisheries and Oceans
before any work can begin, which can
be a lengthy process. Layfield’s
Standard Floating Silt Curtain was
instrumental for the contractor in
receiving his permit to work in the
water.
The company supplied their
Standard Floating Silt Curtain (FSC)
constructed of reinforced polyethylene
(RPE) top and bottom with a Typar®
geotextile body and EC 102 connection
pin. Six standard FSCs, 13’ deep
by 50’ long, were attached end to end
to create a three hundred foot long
continuous curtain to contain the east
shore. The advantages of using 50’ sections
instead of a single long curtain
are the ability to replace any section
due to damage, ability to add or
remove curtains as the construction site changes and ease of construction
and installation. The curtain stayed in
place for over six months during the
construction of the bridge.
Due to the placement right along
the shore the standard FSC is ideal for
these types of projects where there is
little to no flowing water or wave
action. Many situations, such as high
water flow or marine applications,
require significantly different designs.
Layfield can custom design a FSC
with a higher strength RPE top and
bottom and higher strength and higher
flow rate monofilament geotextile
along with a more elaborate anchorage
system and curtain to curtain connection.
Many failures of FSCs are directly
related to the connection between curtains.
Layfield has two alternative
connection details which change the
point loads, with the pin connections,
to strip loads, thereby increasing the
durability and service life of the FSC.
Additionally, higher buoyancy
floats can be used to prevent the submergence
of the curtains in high flow
and wave action situations.
Chang Park is Soil Control &
Reinforcement Specialist with Layfield
Geosynthetics & Industrial Fabrics Ltd.
Contact: cpark@layfieldgroup.com.
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