1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)

Working for Water [South Africa]

Government funded restoration/rehabilitation initiative as part of Working for Water project. Aim was to eradicate alien invasive.

• Compiler: Klaus Kellner
• 01/14/2009 midnight

2.1 Short description of the Technology

Definition of the Technology:

Sediment retention fibre rolls (SRFR) and erosion blankets were deployed to stabilise steep slopes after vegetation cover was destroyed by fire, near the town of Knysna in the Western Cape Province, South Africa

2.2 Detailed description of the Technology

Description:

Sediment retention fibre rolls (SRFR) and erosion blankets were deployed near the town of Knysna in the Western Cape Province of South Africa to stabilise slopes after vegetation was destroyed by wildfires in 2017. The predominant geology is quartzite, shale, schist, conglomerate and dune sand. The soils of this area are generally acidic and nutrient-poor occurring, on moderate to steep slopes, ranging from 5 m to 1,220 m above sea level. The area receives summer and winter rainfall with an annual average of around 650 to 700 mm. The Knysna fires were the worst wildfire disaster in South African history (more than 21 000 ha were affected – destroying more than 800 buildings, 5000 ha of forest plantations and claiming the lives of seven people). Investigations reported that its severity was caused by a cocktail of factors, including drought, low atmospheric humidity, strong warm Bergwind conditions and abundant biomass. After the fires, the lack of vegetation cover on steep sandy slopes in the affected areas posed an immediate danger of erosion and landslides to downstream catchments, ravines and man-made infrastructure. Areas with high infestations of invasive alien plants required active re-establishment of indigenous plants and the removal of alien seedlings (popular and aspen) after germination. It is estimated that 53 km of wood fibre rolls (or "sausages") and 54 000 m² of erosion blankets (Woodwool fibre filled) have been installed on post-fire erosion mitigation projects. Furthermore hydroseeding was carried out with the annual grass "teff" (Eragrostis tef) to serve as an interim (annual grass) soil stabiliser. This will be replaced by indigenous plant growth in time. The project was implemented in the following stages:
1.Identification of priority areas where infrastructure was threatened (using GIS modelling)
2.Acquisition of restoration materials – SRFR and erosion blankets produced through secondary industries created through the removal of invasive alien plants (popular and aspen)
3.Training of local community members on implementation of restoration measures
4.Removal of all burnt woody material
5.Introduction of indigenous seed
6.Installation of erosion control blankets or hydroseeding (seeding using a slurry of seed and mulch)
7.Installation of SRFR
8.As part of maintenance, removal of invasive alien vegetation seedlings

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

South Africa

Region/ State/ Province:

Western Cape

Specify the spread of the Technology:

• evenly spread over an area

If precise area is not known, indicate approximate area covered:

• 10-100 km2

Is/are the technology site(s) located in a permanently protected area?

No

Map

×

2.6 Date of implementation

Indicate year of implementation:

2018

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through projects/ external interventions

3.1 Main purpose(s) of the Technology

• reduce, prevent, restore land degradation
• conserve ecosystem
• protect a watershed/ downstream areas – in combination with other Technologies
• preserve/ improve biodiversity
• reduce risk of disasters

3.2 Current land use type(s) where the Technology is applied

Forest/ woodlands

• (Semi-)natural forests/ woodlands

(Semi-)natural forests/ woodlands: Specify management type:

• Non-wood forest use

Are the trees specified above deciduous or evergreen?

• evergreen

Products and services:

• Protection against natural hazards

Settlements, infrastructure

• Settlements, buildings

Waterways, waterbodies, wetlands

• Drainage lines, waterways

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

• No (Continue with question 3.4)

3.4 Water supply

Water supply for the land on which the Technology is applied:

• rainfed

3.5 SLM group to which the Technology belongs

• improved ground/ vegetation cover
• cross-slope measure

3.6 SLM measures comprising the Technology

vegetative measures

• V2: Grasses and perennial herbaceous plants

structural measures

• S6: Walls, barriers, palisades, fences

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

• Wt: loss of topsoil/ surface erosion
• Wm: mass movements/ landslides

soil erosion by wind

• Eo: offsite degradation effects

water degradation

• Hp: decline of surface water quality

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• prevent land degradation
• restore/ rehabilitate severely degraded land

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

1.Prepare the area to be restored
2.Determine the spacing of the rolls as a function of soil type and slope
3.Installation of erosion rolls (6 m long) and blankets (2.5m x 50 m) must overlap
4.Use wooden stakes to secure the rolls and blankets – rolls (50cm) – 1.2 meter apart, blankets (30cm) – 1meter appart

Author:

Erosion Control Technology Council

Date:

09/11/2021

Technical specifications (related to technical drawing):

1. The first step in the installation of the erosion blankets on slopes is site preparation. Be sure the site is properly prepared before installing any blankets. The site should be fine graded to a smooth profile and relatively free from all weeds, clods, stones, roots, sticks, rivulets, gullies, crusting and caking. Fill any voids and make sure that the slope is compacted properly.
2. At the top of the slope dig an anchor trench 20 cm deep by 20 cm wide. The blankets will be anchored in this trench with staples.
3. Starting at the crest of the slope, roll the blankets down the slope in a controlled manner.
4. Seed the area to be vegetated (hydroseeding).

Author:

Erosion Control Technology Council

Date:

09/11/2021

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology unit

other/ national currency (specify):

Rand

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

15.0

4.3 Establishment activities

4.4 Costs and inputs needed for establishment

If land user bore less than 100% of costs, indicate who covered the remaining costs:

Government

4.5 Maintenance/ recurrent activities

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Labour availability, availability of material, transport cost

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• not relevant

5.3 Soils

5.4 Water availability and quality

Is water salinity a problem?

No

Is flooding of the area occurring?

No

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• state

• municipality owned

• municipality

Are land use rights based on a traditional legal system?

No

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

Biodiversity: vegetation, animals

Climate and disaster risk reduction

6.2 Off-site impacts the Technology has shown

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Climate-related extremes (disasters)

Meteorological disasters

Climatological disasters

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• single cases/ experimental

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

No

6.7 Strengths/ advantages/ opportunities of the Technology

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Title, author, year, ISBN Caring for Natural Rangelands, Ken Coetzee, 978-1-86914-071-7

Available from where? Costs?

https://www.loot.co.za/product/ken-coetzee-caring-for-natural-rangelands/stkr-450-g690

7.3 Links to relevant online information

Title/ description:

KNYSNA FIRES: HOW SOON WE FORGET

URL:

https://www.scli.org.za/knysna-fires-soon-forget

Title/ description:

Sediment retention fiber rolls – general usage and installation guidelines April 2011

URL:

https://www.ectc.org