Runoff Water Harvesting Contour Trenches and Pits in Hilly areas [Uganda]


technologies_3455 - Uganda

Completeness: 94%

1. General information

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

Key resource person(s)

land user:

Wazebekwa Dickson

+25671 3029283

Wanale Highland Farmer Organisation

P.O Box 931 Mbale


Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)
Scaling-up SLM practices by smallholder farmers (IFAD)
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
National Agricultural Research Organisation (NARO) - Uganda

1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?


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


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?



The trenches constructed in these regions address the problem of soil conservation to act as flow barrier (restricting the flow velocity within the safe limit from soil erosion point of view) and facilitate water conservation.

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

A contour trench and pit are an excavated ditch/pit along a uniform level across the slope of land in the top portion of catchment to trap runoff water.

2.2 Detailed description of the Technology


Water harvesting is the deliberate collection and storage of water that runs off on natural or manmade catchment areas. Catchment includes rooftops, compounds, rocky surface or hill slopes or artificially prepared impervious/ semi-pervious land surface. The amount of water harvested depends on the frequency and intensity of rainfall, catchment characteristics, water demands and how much runoff occurs. Contour trenches and pits are one of the oldest and most commonly used water management systems in the hilly areas of Mbale district. Contour trenches and pits are ditches dug along a hillside and run perpendicular to the flow of water. Their main objective is to slow down and attract runoff water which infiltrates into the soil which is used as soil moisture for crop cultivated after a rainfall event.These trenches and pits are constructed and maintained during the dry season. The size of the trenches is based on the slope and soil type. Bulabuli subcounty in Mbale district being a hilly area has trenches which are 5 metres long and 1 metre in width and depth. The materials needed in the construction of the trenches and pits are a hoe and spade. For maintenance they should be checked for build up soil, leaves and branches before the rainy season.The major advantages of rainwater harvesting are that it is simple, cheap, replicable, efficient, sustainable and adaptable and can be applied on any soil type and terrain. It can be implemented in small-scale, easily maintained and requires low investements which suites the rural community in Mbale district. Rainwater harvesting also has been shown an advantage as it reduces soil erosion, improves soil fertility and increases agricultural productivity as it reduces damage on the crops hence increases income and improves livelihood.

2.3 Photos of the Technology

2.4 Videos of the Technology




Wanale subcounty Mbale district

Name of videographer:

Joseline Kashagama

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



Region/ State/ Province:

Eastern Uganda

Further specification of location:

Wahura village, Bunazoma Parish, Wanale subcounty

2.6 Date of implementation

Indicate year of implementation:


If precise year is not known, indicate approximate date:
  • 10-50 years ago

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through land users' innovation

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • improve production
  • reduce, prevent, restore land degradation
  • protect a watershed/ downstream areas – in combination with other Technologies
  • create beneficial economic impact
  • create beneficial social impact

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



  • Annual cropping
  • Perennial (non-woody) cropping
Main crops (cash and food crops):

Irish Potatoes, Coffee and bananas

Settlements, infrastructure

Settlements, infrastructure

  • Settlements, buildings

Land users home

3.3 Further information about land use

Water supply for the land on which the Technology is applied:
  • mixed rainfed-irrigated

Water is trapped from the streams flowing from the hills which is diverted into the farmlands

Number of growing seasons per year:
  • 2

Two rainy seasons between March to May and June to August or October

Livestock density (if relevant):

Cows and goats

3.4 SLM group to which the Technology belongs

  • cross-slope measure
  • water harvesting
  • 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

Most of the farmers in Wanale sub county constructed the trenches and pits as a way to combat soil erosion since the area is hilly

3.6 SLM measures comprising the Technology

structural measures

structural measures

  • S4: Level ditches, pits
  • S7: Water harvesting/ supply/ irrigation equipment

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wt: loss of topsoil/ surface erosion
  • Wg: gully erosion/ gullying
  • Wr: riverbank erosion
physical soil deterioration

physical soil deterioration

  • Pw: waterlogging
  • Ps: subsidence of organic soils, settling of soil
water degradation

water degradation

  • Hs: change in quantity of surface water
  • Hp: decline of surface water quality
  • Hw: reduction of the buffering capacity of wetland areas

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • prevent land degradation
  • reduce land degradation

The technology reduced further land degradation by controlled run off water hence soil and water conservation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology


Prossy Kaheru



4.2 Technical specifications/ explanations of technical drawing

Trenches of 5metres long and one metre in width and depth while the pits are 4metres deep and 5metres in diameter. The materials needed in the construction of the trenches and pits are a hoe and spade. Contour trenches are dug along a hillside and run perpendicular to the flow of water.

4.3 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:
  • per Technology unit
Specify unit:

Trench Line

Specify volume, length, etc. (if relevant):


other/ national currency (specify):

Ugandan Shilling

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:


Indicate average wage cost of hired labour per day:


4.4 Establishment activities

Activity Type of measure Timing
1. Plan according to the topography of the area Structural Before the on set of rains
2. Purchase the materials need Structural Before the on set of rains
3. Measure and indicate Structural Before the on set of rains
4. Construction of the Trenches and pits Structural Before the on set of rains

The establishment activities are done during the dry season.

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 Man Power Trenches 58.0 4000.0 232000.0
Equipment Handhoe piece 3.0 10000.0 30000.0
Equipment Spade piece 3.0 15000.0 45000.0
Total costs for establishment of the Technology 307000.0

The land user bore all the costs since it was self innovative.

4.6 Maintenance/ recurrent activities

Activity Type of measure Timing/ frequency
1. Excavation of soil and other sediments from the trenches Management Annually before on set of rains

Once the trenches and pits are constructed, the land user is only left with digging out the soil that has build up in the trenches.

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 Labour Trenches 58.0 1500.0 87000.0
Equipment Handhoe pieces 2.0 10000.0 20000.0
Equipment Spade Pieces 2.0 15000.0 30000.0
Total costs for maintenance of the Technology 137000.0
If land user bore less than 100% of costs, indicate who covered the remaining costs:

The land user bore all the costs


The maintenance costs are lower since less labour is need to maintain the structures. The land user doesn't have to buy the equipments again since they had been purchased at the beginning during the construction of the trenches.

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:


5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specify average annual rainfall (if known), in mm:


Specifications/ comments on rainfall:

Wanale sub county receives high rainfall because of its high altitude

Agro-climatic zone
  • humid

There's constant flow of streams from the hills which supports agriculture throughout the year

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
Comments and further specifications on topography:

Wanale hills is standing at the height of 6,864 ft

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • medium (loamy, silty)
Soil texture (> 20 cm below surface):
  • medium (loamy, silty)
Topsoil organic matter:
  • medium (1-3%)

5.4 Water availability and quality

Ground water table:

on surface

Availability of surface water:


Water quality (untreated):

good drinking water

Is water salinity a problem?



There' s soil erosion in the hilly areas of Wanale which pollutes the water sources in low land areas

Is flooding of the area occurring?


Comments and further specifications on water quality and quantity:

There's high adaptation of contour trenches in the area

5.5 Biodiversity

Species diversity:
  • medium
Habitat diversity:
  • low
Comments and further specifications on biodiversity:

Most of the land is arable land and less occupied with natural forests

5.6 Characteristics of land users applying the Technology

Sedentary or nomadic:
  • Sedentary
Market orientation of production system:
  • mixed (subsistence/ commercial
Off-farm income:
  • 10-50% of all income
Relative level of wealth:
  • average
Individuals or groups:
  • individual/ household
Level of mechanization:
  • manual work
  • men
Age of land users:
  • elderly
Indicate other relevant characteristics of the land users:

The land user is highly educated (University Level)

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

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
  • medium-scale

There is a lot of land fragmentation due to the high population and inheritance of land among the male children.

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

  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
technical assistance:
  • poor
  • moderate
  • good
employment (e.g. off-farm):
  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
roads and transport:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
financial services:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts


crop production

Comments/ specify:

Reduced crop failure due to soil and water conservation

risk of production failure

Comments/ specify:

The soil is kept moist and it is a source of water for the crops after rains.

land management

Comments/ specify:

Promotes soil and water conservation and salinity of low ground water bodies through control of soil erosion.

Income and costs

farm income

Comments/ specify:

Through increased crop production hence increased sales

diversity of income sources

Comments/ specify:

Source of on farm income to those who provide labour in the digging of the trenches and pits

Socio-cultural impacts

food security/ self-sufficiency

Comments/ specify:

Increased productivity due to reduced crop failure

SLM/ land degradation knowledge

Comments/ specify:

Through knowledge sharing in their farmer groups

conflict mitigation

Comments/ specify:

Reduced soil erosion hence reduced land slides

Ecological impacts

Water cycle/ runoff

surface runoff

Comments/ specify:

Reduced sheet erosion as a result of trenches trapping runoff water


soil moisture

Comments/ specify:

Water is trapped in the trenches which infiltrates into the soil and also used for irrigation

soil loss

Comments/ specify:

Soil is trapped in the trenches and also reduced soil erosion through reduced water runoff

soil accumulation

Comments/ specify:

Soil trapped in the trenches is removed and put into the field


Comments/ specify:

Reduces salinity of water bodies due to reduced soil erosion

soil organic matter/ below ground C

Comments/ specify:

Soil cover or mulch and top soil are conserved

Biodiversity: vegetation, animals

biomass/ above ground C

Comments/ specify:

Ground cover is conserved since sheet erosion is controlled

Climate and disaster risk reduction

flood impacts

Comments/ specify:

Controls flooding to low lands since some water is diverted into the trenches and pits

landslides/ debris flows

Comments/ specify:

Reduced land slides since water is trapped in the trenches and also the water speed is reduced

drought impacts

Comments/ specify:

Water trapped in the trenches and pits is used for crop irrigation

6.2 Off-site impacts the Technology has shown

water availability

Comments/ specify:

Water trapped in the trenches and pits can be used for spraying and making organic manure mixture from animals

downstream flooding

Comments/ specify:

Water is trapped in the trenches hence reduced runoff and water logging in low areas

downstream siltation

Comments/ specify:

Soil is trapped in the trenches

groundwater/ river pollution

Comments/ specify:

Soil erosion is controlled hence controlled salinity of water souces

damage on neighbours' fields

Comments/ specify:

Run off water is trapped hence reduced erosion and flooding in low land areas

damage on public/ private infrastructure

Comments/ specify:

Controlled soil erosion reduces land slides which would have blocked the roads affecting the transport system and maintenance costs

Comments regarding impact assessment:

Contour trenches are mainly dug to control soil erosion which slow down and trap run off water which infiltrates into the soil.

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?
annual temperature increase very well
annual rainfall decrease very well
seasonal rainfall wet/ rainy season decrease very well

Climate-related extremes (disasters)

Hydrological disasters
How does the Technology cope with it?
general (river) flood very well
landslide very well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
extended growing period very well
reduced growing period very well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

slightly negative

Long-term returns:

very positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

very positive

Long-term returns:

very positive


The trenches maintained after two rainy seasons and readily available cheap labour hence low maintenance cost.

6.5 Adoption of the Technology

  • more than 50%
Of all those who have adopted the Technology, how many have did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 90-100%

Landowners have knowledge about the advantages of trenches and there’s readily cheap labour. Availability of Farmer groups in the area hence collective knowledge sharing.

6.6 Adaptation

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


6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Reduces soil erosion
Improves agricultural productivity through infiltration of the water collected in the trenches and pits
water can be used for irrigation and spraying after rains
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Prevents pollutants from draining into the low land water bodies
Reduces salinity of ground water

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?
Trenches silt up and need regular maintenance Regular maintenance
Accidents may occur through drawning Controlled movement of children
The trenches and pits are habitats for mosquitoes
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
Increases land fragmentation since these trenches divide the land into small pieces of land

7. References and links

7.1 Methods/ sources of information

  • field visits, field surveys


  • interviews with land users


  • compilation from reports and other existing documentation


7.2 References to available publications

Title, author, year, ISBN:

Importance of Continuous Contour Trenches (CCT) in Maharashtra by Nitin Bajirao Borse M.V.P.Samaj’s (2016) Arts, Science and Commerce College, Ozar (MIG) Affiliated to SP Pune University

Available from where? Costs?

7.3 Links to relevant information which is available online

Title/ description:

Soil and water conservation Trenches


Title/ description:

Infiltration Trenches (water Absorption Trenches)


Title/ description:

Water Portal / Rainwater Harvesting / Groundwater recharge / Contour trenches


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