Table of Contents
THE NEED FOR RIVER STABILIZATION
In the Western Cape in particular, many of the farming community struggle to combat soil erosion, in agricultural lands generally, as well as along rivers. The erosion of soil along rivers (a part of what is termed ‘river instability’) harms farmers particularly because that is often where the deepest and most fertile soil is to be found in the landscape.
Although it is not an environmentally healthy practise to confine rivers to narrow channels, this has been done over many years prior to the more general understanding of the needs of the environment. The confinement of rivers to these artificially narrow areas in a floodplain is a major factor contributing to the instability of the rivers. Simply widening the river flow area is desirable, but seldom practical, because the farmer’s (and those employed by the farmer) livelihoods depend on agricultural production on the land. So how does this dilemma get addressed?
My approach developed over many years provides what I believe is a novel compromise to this problem. While trying to reduce the impacts of floods on farmers by means of engineered structures, I have found that the judicious use of indigenous wetland plants can be used to support the river stabilization effort (by binding the soil and providing hydraulic roughness which slows down the flow velocity in rivers), and thereby reduce the need for over-designing the structures required to stabilize a river. While it is not practicable to return rivers to their pristine state, the use of indigenous wetland plants certainly provides an ecological offset, because their incorporation in the solution also enhances the biodiversity in the river and provides habitat for other plants, fish, birds and animals that would otherwise have disappeared.
JOB CREATION OPPORTUNITIES
One of the most rewarding aspects of the work that I have done in rivers, has been the realization that through the projects many people have learned new skills and realized employment opportunities.
The use of gabion structures
Planning structures constructed with gabions (groynes and weirs) was my first experience with job creation. The first large project with government funding was the Calitzdorp project (2001) – see the blog https://hanskingsrs.com/2021/02/01/how-did-the-use-of-groynes-for-river-bank-stabilization-in-the-western-cape-develop/) . Initially we tried employing unemployed people using a set daily wage. This was not successful and progress was terribly slow. The project was re-organized so that labour were paid a generous rate per cubic meter gabion packed (based on the minimum wage and the assumption that only a half a cubic meter of rock was packed per person per day). This worked very well, even the people doing the packing were satisfied, and we were able to secure further funds for more projects downstream in the following year. This experience lead the team working with me at the Department of Agriculture to form construction teams in various areas around the Province to replicate this kind of work.
The use of indigenous wetland vegetation
The need for using indigenous wetland vegetation (for river stability, as well as biodiversity enhancement) is described above. The challenge was where to source the plant material and who would look after it till it was established? Some wetland plants are available at commercial nurseries, but only in small quantities. While I was with the Department of Agriculture, two existing community owned and driven nurseries were expanded to greatly improve their capacity. The nursery where I was more involved was started by Working for Wetlands, and was expanded to provide 35 000 plants for use in four projects which I have designed in the area. At this nursery a range of previously unemployed people from the local community were employed to harvest seeds or rhizomes in the field, others to prepare the seeds for planting, others to plant and manage the stock under the nets, and then others to return the plants to the river once the civil works was complete.
The Genadendal nursery project initially created work for 10-15 people for the first two years, but is still operating. The gabion-structure based projects involve much more labour, but for shorter periods. There was however some sustainability of employment for the teams involved with the gabion construction because once trained, they would frequently be used at new projects.
Soil erosion is a major threat to the long-term stability of agricultural production in the Western Cape. The combatting of soil erosion provides many opportunities for job-creation and the starting of small contracting enterprises. For the welfare of everybody in the Province, the combination of resource management and job-creation needs to be supported and promoted.
If you need to contact the community nurseries or are looking for teams to pack gabions contact me via email.