Case study by Kaytech
the drain while water passes through,
thus lowering the phreatic surface in the
surrounding soil.
Upon completion of the project in
October 2017, contractors had installed
2 000 metres each of FloDrain 400mm and
Geopipe M65R, resulting in the effective
interception and control of subsurface
water entering the new layer works. u
process provides several benefits,
including
appreciable
thickness,
high porosity, and a significantly high
drainage capacity in both the transverse
and normal to the plane.
Bidim performs two functions when
incorporated in a subsoil drain: that of
filtering and separating, and fine soil
particles are prevented from entering
B
y February 2017, the development
of the Bergenzicht Country
Estate in the Simonsberg and
Franschhoek mountains in Paarl had
reached Phase 4. Unfortunately, a
leaking dam situated upstream from
the estate was causing a noticeable
rise in the water table. The combination
of this moisture and the iron-rich soil,
for which the area is prone, resulted
in the formation of ferric oxide that, in
turn, can lead to a slimy gel forming,
capable of blocking an entire drain and
polluting groundwater.
The backfill used in the drain was
clean free-draining river sand.
The engineering consultant on site
recognised that conventional drains
for the parking area were not a viable
option; therefore, he specified easy-to-
install FloDrain and Geopipe systems.
These would not only act as cut-off
drains, but importantly, would also
reduce oxygen levels and thereby the
formation of ferric oxide.
A contractor in the Western Cape, who recently experienced difficulty
installing conventional aggregate drains in waterlogged soil, chose to go
with an innovative system.
Two for the price of one
Used for a wide variety of subsoil
drainage problems, is Kaytech’s
ready-made FloDrain and Geopipe
system. The prefabricated FloDrain
is a lightweight, flexible system that
reduces the costs of transportation,
excavation, and labour.
It is installed vertically into a trench,
with a Geopipe positioned and wrapped
in the bidim filter jacket at the base of
the fin. Manufactured from HDPE, the
material is light and flexible and much
easier to handle than other pipes; it
easily accommodates high localised
flows and can tolerate extremely high
stresses. With its 70% perforated
surface area, it allows for the highest
infiltration rate of water compared to
that of any other drainage pipes.
FloDrain is supplied pre-wrapped in
bidim — Kaytech’s continuous filament,
nonwoven, needle-punched geotextile,
manufactured from 100% recycled
polyester.
The
needle-punching
innovations
The solution
Red, orange staining is an indication of ferrous
oxide occurring within the subsoil drain.
Water Sewage & Effluent March/April 2018
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