Well you could call it an embankment but in this case I am going to explain how to get it to grow a lush green wall of plants. It is also a green wall that can save a lot of money and energy on projects where excess fill and spoil needs to be removed. Generally this type of wall will require a fair amount of horizontal space, around 1.5 metres for every metre you want to go high.
Your embankment will cool your development, provide a spectacular feature sequester carbon, and save the expensive removal of spoil. Whilst I'm at it, why not include a paths for exercise and play areas for children. Everyone loves a hill to climb with views.
If is is built well using horticultural techniques it will be beautiful. If not built correctly it may just grow weeds or even worse nothing!
Below is some photos of the green wall so you can get an idea of what I mean. Lets call it "Andrews Farm Green Wall". Below I will provide the specification for this green wall.
Native plants on a successful embankement. In this case the plants were mostly self seeded. Yearly slashing keeps plants looking young and lush.
Two projects I have worked on as green structures are 1. at the Southern end of the M7 Tollway in Sydney and it is called the Pyramid and 2. Sydney Olympic site called Kronos Hill. Both projects required a lot of fill and were great places to put a vast quantities of spoil that was not required on the projects.
M7 Pyramid, this mound was a place for a huge amount of excess fill and is grassed.
Kronos Hill Sydney Olympic site has a track to the top and native plant cover.
Now back to Andrews Farm Green Wall, its 6 metre high and has a base of 8 metres deep. So around a 30 degree angle. In this case it only has one side as it is built against a cliff.
A specification to build such a wall would include the following layers.
A) The first layer and up to 800mm from the surface. Materials could be clay, sand, soil, rock, waste concrete, bitumen, even in large pieces. Is would be good to mix the components especially if there is some clay or soil. Water holding capacity, drainage and porosity is beneficial.
B) Clean fill suitable for plant growth. This layer will be between layer A above and to within 400mm of the surface of your green wall. Water holding capacity, drainage and porosity is essential. A soil test will be required to ensure it is has suitable water holding capacity, drainage and porosity. Send me a sample and I will do an analysis for you. T: :61 468 787 071.
C) Mix 200mm of B) above and D) below.
D) Good growing soil. Send me a sample and I will do an analysis for you. T: :61 468 787 071.
Andrews Green Wall sketch.
Mulching with organic or gravel mulches will help reduce weeds.
Erosion mesh may be required for erosion control, a biodegradable one can be suitable until plants establish.
Temporary or permanent irrigation may be required.
Planting layout and species will be provided by a horticulturalist. Seeds and tubestock can be used to make this quite inexpensive. Around 4 plants per M2 will suffice.
Engineering of mound to avoid erosion will depend on components A, B, C and D above.
Let me know if you have such a project, I would be please to assist you. Contact 0468 787 071 or rob@greenlook.com.au.