In landscaping we are sometime called to deal with a steep slope. Retaining walls are not always a possible or even preferred option. Vegetation will, when chosen carefully, retain the soil in the most effective manner. Selecting plants with various root systems will ensure the soil is retained at different depth.
In the case of steep slopes, erosion control systems must be used in conjunction with planting. This will ensure that the plants root system is not damaged whilst it is establishing, the soil is retained, weeds kept to a minimum and moisture retained. In these cases the erosion control materials functional life must exceed the development of a strong root structure.
There are three stages to be thought of: un-vegetated, immature vegetation, mature vegetation.
In the initial stage the initial assessment will consider factors such as slope length and steepness, rainfall, temperature wind direction, soil analysis to determine its pH and nutrients carrying capacity and the need for further soil improvement.
Once this is done, plants and erosion control system suitable for the site and soil can be chosen. Sometimes multiple products will have to be use to achieve a high-performance solution. For a vegetated slope, biodegradable and natural products with good performance and longer functional life are excellent for erosion and sediment control.
The immature vegetation will need to be looked after for at least 3 months after installation. Post work monitoring and a maintenance schedule should form part of well managed erosion control plan.
Once established the plants’ root systems and green cover will ensure that the slope is stabilized. Over time, the erosion control systems will biodegrade and be used by the plants.
To conclude, a well designed erosion control system must ensure effective protection through maturity. The erosion control plan designer must have test data on product performance in both un-vegetated and vegetated conditions, understand plant growth above and below ground, have knowledge of plant requirements and a maintenance program suited to the site.
About Patrick Regnault
I have worked in the horticultural and landscaping industry for over 35 years in three different countries.I am a member and Registered Horticulturist with the Australian Institute of Horticulture and member of the Housing Industry Association. I am the owner of Interactive Landscapes, a successful structural landscaping and landscape design business. I believe that what gardens and gardening do is to reconnect people with the fundamental elements of nature. A good gardener will try and acquire a profound understanding of the balance of nature and endeavour to do the best to improve the environment in which the garden is situated. At Interactive Landscapes it is a philosophy that we put into practice when designing and creating a garden, no matter the size. Our name reflects this as we understand that gardens are a place of interaction. View all posts by this author »