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)

Southern African Science Service Centre for climate change and Adaptive Land management (SASSCAL)

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

Namibia University of Science and Technology ( NUST) - Namibia

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

German Federal Ministry of Education and Research (BMBF) - Germany

1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

2017

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

2.1 Short description of the Technology

Definition of the Technology:

Construction of contour ditches and ponding banks to trap and infiltrate rainwater for improved growth of plants and replenishment of ground water, while gently spilling any excess water safely over wide areas to avoid erosion during intense rain. It must be integrated with other technologies that treat the root causes of rangeland degradation rather than used as a stand-alone technology to treat symptoms.

2.2 Detailed description of the Technology

Description:

The technology is applied in rangeland where runoff occurs during and soon after rain, where the soil is deep enough to dig contour ditches and construct ponding banks, where there is sufficient gentle slope over a wide enough area for safely spilling excess water during intense rain, where valuable plants can establish themselves or be grown to benefit from the extra infiltrated rainwater, where the costs of earthmoving can soon be recovered through sale of extra production from the valuable plants and, most importantly, where the root causes of rangeland degradation have been addressed, usually through management of grazing and fires. At the appropriate area, contour lines are marked out by any available technology such as laser or dumpy level or mapped by drone. Where bushes grow densely, it may be necessary to clear narrow contour strips while leaving larger trees in place. Ditches can be dug to any depth down to approximately 50cm by mechanised grader or backhoe (a loader or digger attached to a tractor), or manually by pick and spade. The soil should ideally first be ripped where dug soil for the bund will be heaped, to ensure a firm foundation for the heaped soil to form a bund. To stabilise the bund, it should be compacted and creeping herbaceous plants should be encouraged to grow on it. Where water is to be spilled if ditches are full, either less soil needs to be heaped there or, if the ditch is deep enough, the natural ground surface can serve as spillway by avoiding to heap soil on it. In situations where excess water can safely be spilled from outward curves of the down-slope side of a long ditch, the dug soil can be placed as a bund below the long sections of ditch where water does not need to spill. In situations where excess water should rather be spilled evenly over the whole length of ditch, then either a second ditch can be graded below the first ditch, with the dug soil heaped upslope, or all of the dug soil needs to be moved and put to use elsewhere. Such soil could be used for building humps to divert flowing water out of tracks and back into natural flow paths, or to construct banks that divert water flowing down shallow gullies into contour ditches. Since it is almost impossible to dig exactly on contour, water starts to spill over the slightly lower edges of the ditch before the volume of water flow increases sufficiently to spill over the whole edge of the ditch. This results in self reinforcement over successive rainfall periods because herbaceous plants grow more densely at the slightly lower edges due to the greater amount of water that previously spilled there, resulting in more sediment being trapped there and consequent raising of the soil level, also by puffing up of the soil from their root growth and exudates which feed soil organisms. Eventually the previously lower sections are raised higher than other sections of the ditch edge, where subsequent spills wet the soil more for denser plant growth, and this slow self-reinforcing effect continues indefinitely. To avoid spillage over the end of each ditch, a short upward curve is built in when digging the ditch and heaping the bund. Organic material can also be placed in the ditch, or in larger settling ponds along the ditch, to improve nutrient cycling. Infiltration ditches were constructed at intervals of 0.5m height on a 30ha densely bushed portion of Farm Middleplaats and trees were planted below the ditches to grow into a fruitful landscape. Species included large canopy trees such as Faidherbia albida and Acacia erioloba, shorter thornless trees for “chop and drop” mulching, such as Peltophorum africanum and Bolusanthus speciosus, and trees that produce fruits, such as Sclerocarya birrea and Berchemia discolor, or edible leaves, such as Moringa oleifera. The tree seedlings were raised in a nursery on the farm, and he fence around the 30ha had to be strengthened to protect the planted seedlings from oryx. In addition, it was necessary to water the seedlings in the landscape for the first year or two until well established, On another portion of the farm where bushes had previously been cleared and the soil was consequently less fertile, ponding banks of approximately 1m height were constructed, especially in locations where it appeared that water had ponded naturally in the past. The ponded water encourages growth of herbaceous plants, especially where soil is scraped from below the bank so that the soil on its upper side remains undisturbed. A few grasses were dug from a wetland and brought to the farm for later transplanting of propagules into the ponded areas.

2.3 Photos of the Technology

2.4 Videos 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

Indicate year of implementation:

2014

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through projects/ external interventions

Comments (type of project, etc.):

Projects involving students

3.1 Main purpose(s) of the Technology

• improve production
• reduce, prevent, restore land degradation
• preserve/ improve biodiversity
• create beneficial economic impact

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

3.3 Further information about land use

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

• rainfed

Comments:

Except for Initial watering of planted tree seedlings, which was necessitated by drought

Number of growing seasons per year:

• 1

Livestock density (if relevant):

10ha/LSU averaged out over time and not continuous

3.4 SLM group to which the Technology belongs

• agroforestry
• pastoralism and grazing land management
• water harvesting

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:

• 0.1-1 km2

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

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

4.2 Technical specifications/ explanations of technical drawing

Contour strips were cleared by bulldozer at 0.5m height intervals on land with a gradient of approximately 1:100. A line was ripped approximately 0.6m deep, over which soil was heaped for a bund by a grader when digging a ditch on its upper side to hold rainwater at a depth of approximately 0.5m. The ends were hooked upwards by approximately 2m to avoid spillage there, while spillways were created by lowering a 10m length of the bund and staggered between ditches to zig-zag the spilled water slowly down the landscape. A variety of tree seedlings were planted below ditches to provide tall canopies, chop-and-drop mulching and edible leaves or fruits, at intervals of approximately 5m.

4.3 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology area

other/ national currency (specify):

NAD

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	Marking of contour lines	Structural	Dry season
2.	Clearing of bush strips along contour	Structural	Dry season
3.	Ripping along contour	Structural	Dry season
4.	Digging ditch and heaping bund over ripline	Structural	Start of rains
5.	Raising tree seedlings in nursery	Vegetative	Mostly dry season
6.	Planting tree seedlings below ditches	Vegetative	Rainy season
7.	Watering tree seedlings	Vegetative	Dry season
8.	Strengthening fence around landscape to exclude oryx	Structural	When needed

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	Marking of contour lines	Person days	6.0	72.0	432.0	100.0
Labour	Raising tree seedlings in nursery	Person days	20.0	72.0	1440.0	100.0
Labour	Planting tree seedlings below ditches	Person days	10.0	72.0	720.0	100.0
Labour	Watering every 10 days in first year, except after rain	Person days	150.0	72.0	10800.0	100.0
Equipment	Strengthening fence to exclude oryx (Labour)	Person days	100.0	72.0	7200.0	100.0
Equipment	Bulldozer to clear strips and rip	Bulldozer hours	89.0	850.0	75650.0	100.0
Equipment	Grader to dig ditches and heap bunds	Grader hours	35.0	650.0	22750.0	100.0
Equipment	Diesel for bulldozer and grader	Litres	1000.0	12.0	12000.0	100.0
Equipment	Tractor & 7000 lt water trailer every 10 days in first year, except after rain	Tractor days	30.0	1250.0	37500.0	100.0
Plant material	500 Plastic bags / seeds with soil to raise seedllngs	Filled growing bags	500.0	4.0	2000.0	100.0
Construction material	Fencing wire and posts to strengthen fence around fruitful landscape	km of fencing	3.0	2200.0	6600.0	100.0
Total costs for establishment of the Technology					177092.0

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	Maintenance of ditches and bunds by grader	Structural	Rainy season

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
Equipment	Grader cost to maintain the swales every 3 – 4 years	Grader hours	8.0	700.0	5600.0	100.0
Total costs for maintenance of the Technology					5600.0

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

High cost of hiring or operating earthmoving machinery

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• not relevant

Comments and further specifications on topography:

Scattered rocky outcrops

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.

A calcrete layer is occasionally exposed at the soil surfacce

5.4 Water availability and quality

Is water salinity a problem?

Yes

Specify:

The water is only slightly brackish

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 owned or leased by land users applying the Technology

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

Land ownership:

• individual, titled

Land use rights:

• individual

Water use rights:

• individual

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Water availability and quality

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)

Gradual climate change

Gradual climate change

	Season	Type of climatic change/ extreme	How does the Technology cope with it?
other gradual climate change	Increased variability in temperature and rainfall	increase	well

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	well
local thunderstorm	well

Climatological disasters

	How does the Technology cope with it?
heatwave	well
cold wave	well
drought	well
land fire	moderately

Hydrological disasters

	How does the Technology cope with it?
flash flood	well

Biological disasters

	How does the Technology cope with it?
insect/ worm infestation	well

Other climate-related consequences

Other climate-related consequences

	How does the Technology cope with it?
reduced growing period	well

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

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

• 0-10%

6.6 Adaptation

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

Yes

If yes, indicate to which changing conditions it was adapted:

• climatic change/ extremes

Specify adaptation of the Technology (design, material/ species, etc.):

After noticing death of tree seedlings from extreme drought, the decision was taken to irrigate them until sufficiently well established to care for themselves.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Avoids wastage of rainwater lost as runoff from the farm and puts it to good use on the farm.

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Improved water and nutrient cycling, resulting in better plant growth and higher animal production.
Reduced erosion of soil

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?
Death of many tree seedlings	By irrigating tree seedlings until they are sufficiently well established to care for themselves, which may take one or two years.

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
High cost of earthmoving	Growing of high value plants to recoup costs as quickly as possible, such as Moringa and dates.

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Rainwater harvesting for drylands and beyond: Vol 2 – Water-harvesting earthworks, Lancaster, 0-977-246418

Available from where? Costs?

https://www.amazon.com/Rainwater-Harvesting-Drylands-Beyond-Vol/dp/0977246418 $28

7.3 Links to relevant information which is available online

Title/ description:

Planning and managing farm roads Manual

URL:

www.sasscal.org/downloads/Planning_and_managing_farm_roads_in_Namibia.pdf

Title/ description:

Rangeland Rehydration Field Guide

URL:

https://emulandrecovery.org.au/~emulandr/files/Rangeland-Rehydration-Field-Guide.pdf