Floating Raft

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Bestmann Green Systems®

The BGS – AquaGreen® Floating Raft
 
More and more floating vegetation elements are used in landscaping, preservation of
natural areas, water course care, aquatic construction and in landscape engineering.  
The employed materials should be an answer to technical as well as aesthetical demands.
The AquaGreen®-Floating Raft combines these two functions being at the same time a
design and a technical element. In addition this small-scale, highly structured raft creates
a new colonization area for many animal and plant species; in this sense it contributes to
the ecological value of any water body.

 The AquaGreen®-Floating Raft is constructed of two Armaflor®-Roll Sods that hold the
floating device, formed from Repotex® I2, in between them. The floating element is
resistant against decaying as well as UV radiation. All the three elements are flexible, yet
tightly bound together. At the moment of installation the vegetation on the supports can
already be completely developed. Its shape is best compared to that of trimaran, where
three adjacent elements are bound together.
The diameter of the AquaGreen®Roll Sods and the floating roll is typically 20cm/8’’;
consequently the width of the complete raft will be between 60-65cm/24’’-25’’. The
standard length of the raft is 2.30-3.00m(7.5’-10’); a multitude of individual rafts can be
combined in modules to create an unlimited variety of forms and configurations.  
The three raft elements are bound together by a strong PP cord, spun or wound around the
three rolls.
The combination with other floating elements (docks etc) or permanent non-floating
installations is also possible. For installations on sites with variable water levels we offer
specially engineered anchoring devices.

Our AquaGreen® Floating Rafts are typically planted with low growing reeds, sedges and
irises. The plants will form a web of rhizomes and  roots under the raft that will form a
submerged biomass inside and under the raft; this biomass creates additional buoyancy:
by the buoyant intercellular spaces inside the plants and by small gas bubbles created by
the micro-organisms that colonize raft and root system. The weight of the plants
counteracts and balances this buoyancy.
The plants used to colonize the floating systems and rafts have to be strictly indigenous,
especially local reeds and other riparian plants. Slow growing species are preferred as
they give more stability on the small rafts and create better hydrostatic conditions.  
The symmetrical construction of two vegetation supports around one floating device
guaranties sufficient stability also in wavy conditions. The width of the rafts can be
enhanced by lateral additions of other rafts; this will also increase the overall stability of
the raft system. 
Floating Rafts have proven their quality in countless field applications since now 20
years.  
 
Material 

Typically any raft consists of two materials: an inert floating matrix and a slowly
degradable (± three years) planting matrix.  
The main criterion that guides the choice of suitable materials for the floating matrix is its
inertia and physical stability; no chemicals should be allowed to leak into the water body
at any time. All AquaGreen® products fulfill this requirement. The floating strands in the
Repotex® mats are made of foamed PE. All these materials are resistant against
microorganisms, UV radiation, aging and corrosion. 
For the planting matrix we typically use natural coir fibers. This has become a standard
ecological engineering technology. The optional netting around them is made of inert
plastic.  
 
Accessories: 
•  Underwater Aprons to protect the raft and rhizome network from too high water
currents; it can also be used as a sediment- and oil-trap.  
•  Anchoring. To anchor the rafts, we use a 5mm (1/4’’) strong PE covered stainless
steel rope, which is placed inside the raft along the protective netting. The rope
will be attached to anchor stones or on shore.