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The main element in all our work is the use of vegetation as a key stabilising and functioning component. Commonly termed ‘bioengineering’, the use of vegetation in soil stability, biodiversity and water quality issues is ever increasing. Salix lead the way in this innovative discipline.
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Rivers and Wetlands
www.salixrw.com
DesignFrom concept to completion, our experience, design capability and installation teams deliver sustainable bioengineering techniques that address the challenges found in scour protection, soil erosion, habitat creation and mitigation projects.
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An introduction to SalixWe recognise that certain components of any project may require the use of concrete, steel or imported aggregates, however our designers always work to minimise the impact of these hard techniques, proving that a mix of hard and soft techniques can still be considered a bioengineered solution.
Our past projects have demonstrated that there are cost savings in using bioengineering solutions in place of hard revetments and that our environmentally sensitive revetments are often more durable.
Employing a solutions driven specialist such as Salix at concept stage can bring tangible benefits to your project.
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Salix strive to achieve harmony between hard civil engineering techniques and our ecologically sound alternatives
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Case Study 1: River Ebbw - Riverbank erosion control and habitat creationWe realised very early on that this project gave us a chance to demonstrate that bioengineered revetments could be cost effective, durable, sustainable and aesthetically preferable to hard engineering solutions.
The original proposal utilised a swathe of blockstone from the crest of the riverbank to the toe, effectively stone cladding over 800 linear metres of the highly erodible colliery shale river bank.
Working with the Clients consulting geotechnical engineers we wanted to explore the possibility of using greener and more cost effective
bioengineering methods which would provide underlying engineering stability whilst providing an ecological resource and improving the visual landscape.
Our design dealt with two basic elements, a slope length of 8-15m with a gradient of 1 in 1.5 and the toe of the embankment with flow velocities of up to 4m/sec.
The toe of the bank was protected using a combination of rock rolls and living willow brushwood faggots.
The upper bank was protected using two high performance erosion control mats; NAG VMax3 P550 andNAG VMax3 C350.
Independent research and thousands of applications across the world have shown these products to beable to withstand extremely high flow velocities (7.6m/s – P550 and 6m/s C350) when vegetated.
Even prior to vegetation establishment the composite fibre layer provides exceptional erosion controlperformance (3.8m/s – P550 and 3.2m/s – C350).
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River Ebbw during restorative works.
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Case Study 2: Twycross Zoo - Wetland System
The challenge at Twycross Zoo was to create a 3 hectare wetlandsystem to provide waste water treatment and habitat creationcomprised of wet grasslands, reedbeds and ditches plus eighteenintegrated ponds.
Salix won this interesting project after a competitive tender process which included full CDM regulationcompliance.
Importantly, we were then able to act as Principal Contractor which enabled us to design and install avery diverse range of solutions from our portfolio of sustainable, ecologically sound techniques. During this process Salix’s close supervision via experienced personnel meant that the scheme was completed on time and within budget meeting the Client’s aspirations for the finished scheme’s functionality, sustainability and visual impact.
The complex earthworks comprised of bulk earthmoving (28,000m3) and micro profiling to create 18integrated ponds, wet grassland, ditches and gravel reedbeds.
Of critical importance during all this activity was the successful implementation of our site traffic management plan together with considerate working methods to avoid impacting on the Zoo and adjacent wildlife habitats.
In order to link the wetlands, a series of hard engineered grade control structures, pipe connections and concrete outlets were seamlessly integrated within our design which worked well with our softengineering.
To afford pedestrian access we built 800 metres of foot path, re-established 20,000 m2 of grasslandusing both hydro-seeding and drill seeding techniques and, at our own wetland plant nursery, grew28,000 wetland plants consisting of over 30 different species which were then used to complete the project.
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Salix River & Wetland Services LimitedSalix, Croxton Park, Thetford, Norfolk IP24 1LSTelephone 0870 350 1851 Fax 0870 350 1852 Email [email protected]
