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

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1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

13/03/2000

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

Yes

2.1 Short description of the Technology

Definition of the Technology:

Drainage of saturated and salinised soils by means of sub-soil drainage pipes

2.2 Detailed description of the Technology

Description:

There is a lot of soil, wind and water erosion in this area. River erosion, not related to this SWC, is a problem over the whole area (on average 20 t/ha/y). Sheet and gully erosion occurs on commercial land. The whole area along the rivers varies up to 50 km.

In some places drainage is inadequate and water-logging occurs. A system of sub-soil perforated pipes with surrounding filters was installed. Pipes laid at spacing determined according to the site conditions.
The overall purpose was to limit the level of the water table in the soil profile and remove salts, to provide an adequately aerated zone in the soil for a crops’ root system.

The system must be planned by a suitably trained person and constructed by an expert.

Drainage pipes must be flushed at least annually and roots removed whenever present.

2.3 Photos of the Technology

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

2.6 Date of implementation

If precise year is not known, indicate approximate date:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through projects/ external interventions

Comments (type of project, etc.):

Holland, USA - literature

3.1 Main purpose(s) of the Technology

• reduce, prevent, restore land degradation

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

Comments:

Major land use problems (compiler’s opinion): Bad management (over irrigation). The washing of soil from one land to the other. High winter rainfall.

Major land use problems (land users’ perception): Loss of crop production due to saturation/salinisation of soil. Not putting money back what would be expect, because not enough growth, reduced crop roots deeper in soil and no growth in the area, slanted growth - salinised soils.

3.3 Further information about land use

Number of growing seasons per year:

• 1

Specify:

Longest growing period in days: 120; Longest growing period from month to month: Sep - Mar

3.4 SLM group to which the Technology belongs

• irrigation management (incl. water supply, drainage)

3.5 Spread of the Technology

Specify the spread of the Technology:

• evenly spread over an area

If the Technology is evenly spread over an area, indicate approximate area covered:

• 100-1,000 km2

Comments:

Total area covered by the SLM Technology is 240 km2.

Technology also applied in other provinces. Boland 60% under agriculture and from this 20% under this technology. Swartland mainly wheat, 10% under irrigation and from this 20% is already drained. Southern Cape: 20% irrigated of which 20% is drained, 95% commercial farmers. Other parts in SA: KwaZulu/Natal (Pongola), Free state (Rietriver, Orange River), Northern Cape (Vaalharts, Douglas, Upington), Eastern Cape (Fish River, Sundays River, Langkloof)

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

Comments:

Secondary types of degradation addressed: Cs: salinisation / alkalinisation

Main causes of degradation: other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (Rising water tables - As result of over irrigation, leaking dams and canals)

Secondary causes of degradation: education, access to knowledge and support services (Lack of knowledge - Build dams & canals that leak, over irrigation)

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

4.2 Technical specifications/ explanations of technical drawing

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: moderate

Main technical functions: Removal of salts from soils, Decrease water table, Increase of soil aeration

Structural measure: subsurface drains
Vertical interval between structures (m): n/a
Spacing between structures (m): 40-80
Depth of ditches/pits/dams (m): 1.5-2.5
Length of ditches/pits/dams (m): 300

Construction material (other): Plastic perforated pipe with crushed stone filter

Slope (which determines the spacing indicated above): 2%

Lateral gradient along the structure: 2%

4.3 General information regarding the calculation of inputs and costs

Specify currency used for cost calculations:

• US Dollars

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	Dig trench	Structural	150m/day, dry season Dec-Apr
2.	Lay pipe	Structural	150m/day, dry season Dec-Apr
3.	Place filter material	Structural	150m/day, dry season Dec-Apr
4.	Build manholes	Structural	150m/day, dry season Dec-Apr
5.	Backfill trench	Structural	150m/day, dry season Dec-Apr

4.5 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Install drainage system	persons/day/ha	10.0	15.0	150.0	75.0
Equipment	Machine use	ha	1.0	450.0	450.0	75.0
Construction material	Stone	ha	1.0	100.0	100.0	75.0
Construction material	Pipes	ha	1.0	240.0	240.0	75.0
Construction material	Manholes	ha	1.0	250.0	250.0	75.0
Other	Contractor overheads	ha	1.0	200.0	200.0	75.0
Total costs for establishment of the Technology					1390.0

Comments:

Duration of establishment phase: 12 month(s)

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	Flush pipes with water	Structural	All year/2 times a year
2.	Cut roots in pipes	Structural	When required/
3.	Clean manholes	Structural	All year/2 times a year (was reduced)

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

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Maintenance	ha	1.0	25.0	25.0	100.0
Total costs for maintenance of the Technology					25.0

Comments:

Length of pipe (grid at 60 m spacing - i.e. pipe that average team lays in one day)

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Suitability of soil for drainage (greater depth and permeability = lower costs.

5.1 Climate

5.2 Topography

5.3 Soils

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil fertility is medium - low

Soil drainage / infiltration is medium

Soil water storage capacity is low

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Population density: 50-100 persons/km2

Annual population growth: 1% - 2%

20% of the land users are rich and own 30% of the land.
60% of the land users are average wealthy and own 50% of the land.
20% of the land users are poor and own 20% of the land.

Off-farm income specification: Most of them are only farmers.

Level of mechanization: Tractors, trailer, plough, crop sprayers

5.7 Average area of land owned or leased by land users applying the Technology

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

Land ownership:

• group
• individual, titled

Land use rights:

• communal (organized)
• individual

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Other socio-economic impacts

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

Other ecological impacts

6.2 Off-site impacts the Technology has shown

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

• 10-50%

If available, quantify (no. of households and/ or area covered):

50 percent of all households in this area

Of all those who have adopted the Technology, how many have did so spontaneously, i.e. without receiving any material incentives/ payments?

• 10-50%

Comments:

50% of land user families have adopted the Technology with external material support

Comments on acceptance with external material support: estimates

50% of land user families have adopted the Technology without any external material support

Comments on spontaneous adoption: estimates

There is a moderate trend towards spontaneous adoption of the Technology

Comments on adoption trend: More and more farmers are coming to do ditch drainage because there's more money available, if waiting period is more than 3 months the service from government is free of charge.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Greatly improved crop yield
Improved access for mechanisation

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Greatly improved crop yield
Improved access for mechanisation

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

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
Initial capital outlay
Slight decreased in run-off water quality
Insufficient information on soil properties

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Initial capital outlay
Slight decreased in run-off water quality
Insufficient information on soil properties

7.2 References to available publications

Title, author, year, ISBN:

Drainage Works for Western Cape (Afrikaans). July 1988.

Available from where? Costs?

HE King

Title, author, year, ISBN:

National Drainage Manual (Afrikaans)

Available from where? Costs?

NDA - photostat costs