Hillside Terracing
Ethiopia - Yegara irken (Amharic), Kenetawi metrebawi zala
(Tigrigna)
A hillside terrace is a structure along the contour, where a
strip of land is levelled for tree planting.
Hillside terraces are up to 1 metre wide and constructed at about 2-5 m vertical inteals.
Hillside terraces should only be applied if there is a strong necessity of erosion control
and/or water conservation justifying their construction. In Ethiopia and Eritrea, they
have been mainly applied in the highlands, although the area of their applicability
would be rather in the drier and lower lying agroclimatic zones. Slope range is 50-100%,
soil range particularly on eavily degraded land. Hillside terraces are mainly used to
prevent damage of flooding the area below steep slopes. Hillside terraces help retain
runoff and sediment on steep sloping land and to accommodate tree seedlings to be
planted on them. They are also effective on badlands and in areas with low rainfall to
conserve water. Hillside terraces are usually combined with area closure (against
grazing). Little materials are needed for their construction: Line levels, digging
instruments, stones, and other materials as needed for combined measures. Little
management is needed for their maintenance, except for taking care of the tees
planted, and for correcting damage that may be caused by livestock grazing.
left: Hillside terraces.Spacing between
trees is 2m, and the vertical interval
between terraces also 2 m. The area
between two terraces is undisturbed
and used for forage production. (In:
Soil conservation in Ethiopia, CFSCDD
1986) (Photo: Joerg Wetzel, SCRP)
Location: Harerge, Shewa, Wello,
Tigray, Gonder, Sidamo, and Hamasien
(Eritrea)
Technology area: 1800 km2
Conservation measure: structural
Origin: Developed externally /
introduced through project, traditional
(>50 years ago)
Land use type:
Grazing land: Extensive grazing land
Forests / woodlands: Plantations,
afforestations
Climate: subhumid
WOCAT database reference:
T_ETH004en
Related approach:
Compiled by: Hans Hurni, Centre for
Development and Environment (CDE)
Date: 1995-06-27
Classification
Land use problems:
- High run-on from steep slopes onto cultivated land. Sheet and rill erosion from slopes, and subsequent gullying on cultivated
land along footslopes. Lack of grass and woody biomass. (expert's point of view)
Lack of grazing for livestock. Lack of cultivation land. General food deficiency. (land user's point of view)
Land use
Climate
Degradation
Conservation measure
Extensive grazing land
Plantations, afforestations
rainfed
rainfed, full irrigation
subhumid
Soil erosion by water: loss of
topsoil / surface erosion
Structural: Bench terraces
(slope of terrace bed <6%)
Stage of intervention
Prevention
Mitigation / Reduction
Rehabilitation
Origin
Level of technical knowledge
Land users initiative
Experiments / Research
Externally introduced: traditional (>50 years ago)
Agricultural advisor
Land user
Main causes of land degradation:
Main technical functions:
- reduction of slope angle
- increase of infiltration
- water harvesting / increase water supply
Secondary technical functions:
- reduction of slope length
- improvement of ground cover
- increase of surface roughness
Environment
Natural Environment
Average annual rainfall
(mm)
> 4000 mm
3000-4000 mm
2000-3000 mm
1500-2000 mm
1000-1500 mm
750-1000 mm
500-750 mm
250-500 mm
< 250 mm
Soil depth (cm)
0-20
20-50
50-80
80-120
>120
Altitude (m a.s.l.)
Landform
> 4000
3000-4000
2500-3000
2000-2500
1500-2000
1000-1500
500-1000
100-500
<100
Growing season(s): 90 days(May - Oct), 30
days(Feb - Apr)
Soil texture: coarse / light (sandy)
Soil fertility: low
Topsoil organic matter: low (<1%)
Soil drainage/infiltration: good
Slope (%)
plateau / plains
ridges
mountain slopes
hill slopes
footslopes
valley floors
flat
gentle
moderate
rolling
hilly
steep
very steep
Soil water storage capacity: low
Human Environment
Grazing land per
household (ha)
<0.5
0.5-1
1-2
2-5
5-15
15-50
50-100
100-500
500-1,000
1,000-10,000
>10,000
Population density: 50-100 persons/km2
Annual population growth: 2% - 3%
Land ownership: state
Land use rights: communal (organised)
Relative level of wealth: poor, which
represents 60% of the land users; 10% of the
total area is owned by poor land users
Importance of off-farm income: less than
10% of all income: Labour offered to projects.
Access to service and infrastructure:
Market orientation:
Technical drawing
Hillside terrace cross-section. Linied out along
the contour, vertical interval between two
terraces 2-5 m. (In: Soil Conservation in
Ethiopia. CFSCDD, 1986) (Joerg Wetzel, SCRP)
Implementation activities, inputs and costs
Establishment activities
- 1. transplanting
- 2. seeding
- Construction
- Planting
- community guarding of closed areas
Maintenance/recurrent activities
- 1. weeding
- Control of grazing
- Care taking of seedlings
- communty guarding of closed areas
Remarks:
Slope, soil condition, length of terrace per hectare.
Length of structure on an average slope
Assessment
Impacts of the Technology
Production and socio-economic benefits
Production and socio-economic disadvantages
Socio-cultural benefits
Socio-cultural disadvantages
Ecological benefits
Ecological disadvantages
Off-site benefits
Off-site disadvantages
Contribution to human well-being / livelihoods
Benefits /costs according to land user
Benefits compared with costs
short-term:
long-term:
Establishment
negative
positive
Maintenance / recurrent
positive
very positive
Acceptance / adoption:
80% of land user families (30000 families; 20% of area) have implemented the technology with external material support.
estimates
2% of land user families (600 families; 1% of area) have implemented the technology voluntary. estimates
There is little trend towards (growing) spontaneous adoption of the technology. Very recently, some villages have begun to see
the value of hillside terracing, afforestations and area closure if they are given full responsibility to manage the area by a
group of land users.
Concluding statements
Strengths and
how to sustain/improve
Weaknesses and
Copyright (c) WOCAT (2017)
how to overcome