A PREAMBLE TO SOIL EROSION CONTROL
Ecological rehabilitation is a great deal more than a technical management challenge. Working on rehabilitation projects is a way in which we can establish a balanced and healthy ethical relationship with our natural environment. Working with our hands in the soil literally brings us “back to earth”. If properly done, rehabilitation projects heal more than the scars of man’s careless actions, it also inspires people to care more for their natural environment.
Rehabilitation works should not attempt to restore the ecosystem to some particular condition; they should rather be aimed at “kick-starting” the process of natural succession and healing. If this natural process can be restored, or even partially restored, nature will continue the process and develop into whatever it is able to. In degraded areas, we should thus aim to give nature a helping hand wherever we can, thereafter it will take over and do the rest.
Our rehabilitation efforts, whatever they may be, will rarely result in a completely finished product or condition. They will result in a beginning, an early stage of a natural succession. Our efforts will set a process in motion by creating the dynamics for natural development in the long run.
One must, however, think about the end result and what it may look like when the system is beginning to function. You need to create a vision of what you would like to achieve. Once this is done the planning of erosion control work can commence.
Because we care about nature and our natural habitats, we must make others aware that their use of the land has environmental consequences. We need to give them incentives to change their use of the land to be more environmentally appropriate and to use natural resources more sustainably, for their own benefit.
Redirecting long-standing and harmful land-use behaviour is much more difficult than actually rehabilitating the wounds and scars that result from the ill-considered actions of the uninformed. The rehabilitation practitioner must therefore also be something of a teacher because after all, “prevention is always better than a cure”.
Combatting soil erosion is based on a land ethic that drives the practitioner to repair what has been damaged. It is something of an art and the truly committed person drives in every peg, or places every stone, with the insight that is derived from experience and some instruction.
Successful soil erosion control can never be based only on the remuneration that is involved in a rehabilitation contract; it must be based on something more human, something from the heart, an ethical relationship with the land.
INTRODUCTION TO SOIL EROSION CONTROL
In this booklet, the methods that can be used to rehabilitate the degraded parts of the landscape in the GCBR are described in detail and some of the good results that can be relatively easily (and fairly inexpensively) achieved are shown.
The first step in the rehabilitation process is to eliminate the cause of habitat degradation. If the cause is historical overgrazing, then all that is required is to exclude rehabilitation sites from grazing until the protective vegetation cover is again well established and can be safely utilized. This may require a number of growing seasons, a realistic period of no less than two or three years with normal rainfall for the area is probably a practical guideline but it very much depends on the particular site and how degraded it was to begin with.
The methods recommended are easy to implement using unskilled, but carefully supervised workers. The cost of implementation is a major consideration and the methods show the minimum of effort and costs required for the effective rehabilitation of degraded habitat. It is an unfortunate fact that if rehabilitation is seen by landowners to be too costly, it will simply not be done.
It is important to appreciate that habitat rehabilitation often needs to be done in areas of extreme climatic conditions, which makes successful rehabilitation difficult. The methods shown here focus on the rehydration of the soil and the creation of a more favourable micro-climate that will give germinating plants the best chance for survival on treated sites.
An important aspect of rehabilitation work which is often completely neglected, is the much needed follow-up maintenance of rehabilitation efforts. After installation, the erosion control structures and treatments need constant attention (particularly after heavy rainfall) to ensure that they remain effective and that they will continue to contribute to gradual but significant habitat improvement.
This chapter will hopefully help the rehabilitation practitioner, or landowner, to identify the degraded sites that need to be treated and to provide a guideline for practical and cost effective methods that can be used to combat each type of soil erosion.
Careful attention to detail is a prerequisite for the planning and implementation of soil erosion control work irrespective of the habitat type, or environment, in which it is to be done.
As with all kinds of field practice, the methods described must be suitably modified in order to accommodate any particular site or condition, but it is critical that the basic principles, as described for each method, are used as a guide. There are many additional methods that could also be used in the control of soil erosion, but the methods described have been very well tested, and have proved to be practical in terms of cost, ease of implementation and also suitable for most habitat conditions.