1.2 Coordonnées des personnes-ressources et des institutions impliquées dans l'évaluation et la documentation de la Technologie

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Mekelle University (Mekelle University) - Ethiopie

1.3 Conditions relatives à l'utilisation par WOCAT des données documentées

Quand les données ont-elles été compilées (sur le terrain)?

11/11/2012

Le compilateur et la(les) personne(s) ressource(s) acceptent les conditions relatives à l'utilisation par WOCAT des données documentées:

Oui

2.1 Courte description de la Technologie

Définition de la Technologie:

These consist of stone embankments built in the shape of a semi circle with the tips of the bund on the contour and are arranged in staggered orientation in rows so that overflow from one row will run into the next downslope.

2.2 Description détaillée de la Technologie

Description:

Large semi circular stone bunds are constructed by excavating a foundation of 0.1 - 0.2 m following the semi circle and building of the embankment using stones with a decreasing height at the tips to evacuate excess runoff. 1 - 3 pits are excavated within the semi circle for for planting trees.

Large semi circular stone bunds (Large half moons) are constructed with a diameter of 6 m and corresponding perimeter/length of 9.42 m. The spacing between the tips of adjacent bunds within a row and between the base bund and tip of adjacent rows is 3 m. The height of the embankment varies from 0.5 - 0.75 m at the base bund to 0.4 - 0.5 m at the tip while the corresponding width varies from 0.4 - 0.5 m to 0.2 - 0.3 m. The planting pit has a diameter and depth of 0.3 m.

Purpose of the Technology: Large semi circular stone bunds assist in decreasing slope length, runoff velocity and soil loss; and improving runoff harvesting, soil moisture and groundwater recharge.

Establishment / maintenance activities and inputs: The establishment of large semi circular stone bunds involves collection of stones, alignment of a contour and the semi circle, excavation of foundation, construction of the embankment and digging of planting pits and runoff harvesting ditch. The maintenance includes re-enforcing the embankment and dredging sediment from runoff harvesting ditch during the dry season.

Natural / human environment: Large semi circular stone bunds are implemented in foot (5 - 8%) and hill (8 - 16%) slopes and in medium and light soil types of shallow to moderate depth (0.2 - 0.8 m). It reduces runoff amount and velocity thereby decreasing soil loss and desertification/land degradation. It also improves soil moisture availability and groundwater recharge.

It is mostly constructed using communal labour and there is a moderate trend of spontaneous adoption. The technology is witnessed to be increasing fruit and fodder production thereby improving the livelihood of the land users. It, however, demands high labour especially during establishment.

2.3 Photos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

2.6 Date de mise en œuvre de la Technologie

Si l'année précise est inconnue, indiquez la date approximative: :

• il y a moins de 10 ans (récemment)

2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• par le biais de projets/ d'interventions extérieures

3.1 Principal(aux) objectif(s) de la Technologie

• réduire, prévenir, restaurer les terres dégradées

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Commentaires:

Major land use problems (compiler’s opinion): Deforestation, soil erosion, overgrazing, decline of soil fertility and productivity.

Major land use problems (land users’ perception): Decrease soil moisture, drought, soil erosion, decrease fodder production and shortage of fuel wood.

Plantation forestry: Deforestation

Forest products and services: timber, fuelwood, fruits and nuts, grazing / browsing, nature conservation / protection

3.3 Informations complémentaires sur l'utilisation des terres

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• pluvial

Nombre de période de croissance par an: :

• 1

Précisez:

Longest growing period in days: 150 Longest growing period from month to month: June - November

3.4 Groupe de GDT auquel appartient la Technologie

• mesures en travers de la pente
• gestion des eaux souterraines

3.5 Diffusion de la Technologie

Spécifiez la diffusion de la Technologie:

• répartie uniformément sur une zone

Si la Technologie est uniformément répartie sur une zone, indiquez la superficie couverte approximative:

• 10-100 km2

3.6 Mesures de GDT constituant la Technologie

Commentaires:

Main measures: structural measures

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion

Secondary types of degradation addressed: Wg: gully erosion / gullying, Wo: offsite degradation effects, Bc: reduction of vegetation cover, Bs: quality and species composition /diversity decline

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires), Heavy / extreme rainfall (intensity/amounts), other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (Steep topography), population pressure

Secondary causes of degradation: over-exploitation of vegetation for domestic use, overgrazing, droughts, land tenure, poverty / wealth, education, access to knowledge and support services

3.8 Prévention, réduction de la dégradation ou réhabilitation des terres dégradées

Spécifiez l'objectif de la Technologie au regard de la dégradation des terres:

• réduire la dégradation des terres
• restaurer/ réhabiliter des terres sévèrement dégradées

Commentaires:

Secondary goals: rehabilitation / reclamation of denuded land

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

Large semi circular stone bunds are stone embankments built in the shape of a semi circle with the tips of the bund on the contour and are arranged in staggered orientation in rows so that overflow from one row will run into the next downslope.

Location: Tigray. Kilte Awlaelo

Date: 10/10/2014

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: low

Main technical functions: control of dispersed runoff: retain / trap, reduction of slope length

Secondary technical functions: increase of infiltration, increase / maintain water stored in soil, increase of groundwater level / recharge of groundwater, sediment retention / trapping, sediment harvesting, increase of biomass (quantity)

Bund/ bank: semi-circular/V shaped trapezoidal
Vertical interval between structures (m): 0.2 - 0.3
Spacing between structures (m): 3
Depth of ditches/pits/dams (m): 1
Width of ditches/pits/dams (m): 1
Length of ditches/pits/dams (m): 1
Height of bunds/banks/others (m): 0.5 - 0.75
Width of bunds/banks/others (m): 0.4 - 0.5
Length of bunds/banks/others (m): 9.42

Construction material (stone): The embankment of the semi circular bunds is constructed by the stones.

Slope (which determines the spacing indicated above): 6.5 and 12%

Lateral gradient along the structure: 0%

4.3 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

Birr

Indiquer le taux de change du dollars en monnaie locale (si pertinent): 1 USD= :

18,0

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Collection of stones, contour and semi circle alignment, excavation of foundation, construction of bunds and excavation of planting pits and water storage ditch.	Structurel	January - May

4.5 Coûts et intrants nécessaires à la mise en place

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Labour	ha	1,0	3667,0	3667,0	60,0
Equipements	Tools	ha	1,0	75,0	75,0
Coût total de mise en place de la Technologie					3742,0

Commentaires:

Duration of establishment phase: 24 month(s)

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Replacement of displaced stones and dredging of planting pits and storage ditch	Structurel	January - May

4.7 Coûts et intrants nécessaires aux activités d'entretien/ récurrentes (par an)

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Labour	ha	1,0	117,0	117,0	100,0
Coût total d'entretien de la Technologie					117,0

Commentaires:

Machinery/ tools: Line level, tape meter, digging hoe, shovel, hammer

The cost was calculated for a semi circular bund of 6 m diameter, spacing between the tips of adjacent bunds within a row of 3 m and spacing between a base bund of one row and the tip of the next row of 3 m. This arrangement results in a construction of 2.5 bunds over 94.5 square meter area and a total of 264 bunds per ha.

The construction of one large semi circular stone bund and excavation of the planting pits and runoff harvesting ditch requires 5 person days during establishment while maintaining it needs 0.2 person days.The cost calculation rates apply to 2012. Accordingly, the daily labour wage is 40 Birr for light work such as sediment dredging and 50 Birr for medium work such as stone collection.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

Labour, slope, stone availability and size.

5.1 Climat

5.2 Topographie

Commentaires et précisions supplémentaires sur la topographie:

Slopes on average: An average slope of 6.5% is taken for moderate/foot slope and 12% for hill slope.

5.3 Sols

Si disponible, joignez une description complète du sol ou précisez les informations disponibles, par ex., type de sol, pH/ acidité du sol, capacité d'échange cationique, azote, salinité, etc.

Soil depth on average: Shallow (ranked 1) and moderately deep (Fruit tree plantation on deeper soils, ranked 2)
Soil fertility is low (medium soils, ranked 1) and very low (Light soils, ranked 2)
Soil drainage/infiltration is poor (ranked 1) and medium (ranked 2, Drainage is restricted by the soil depth)
Soil water storage capacity is medium (Medium soils, ranked 1) and low (light soils, ranked 2)

5.4 Disponibilité et qualité de l'eau

5.5 Biodiversité

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

Indiquez toute autre caractéristique pertinente des exploitants des terres:

Land users applying the Technology are mainly common / average land users

Population density: 100-200 persons/km2

Annual population growth: 2% - 3%

10% of the land users are rich and own 10% of the land.
60% of the land users are average wealthy and own 55% of the land (35 Birr/day/person).
30% of the land users are poor and own 35% of the land.

5.7 Superficie moyenne des terres détenues ou louées par les exploitants appliquant la Technologie

5.8 Propriété foncière, droits d’utilisation des terres et de l'eau

Propriété foncière:

• état

Droits d’utilisation des terres:

• communautaire (organisé)
• individuel

5.9 Accès aux services et aux infrastructures

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Revenus et coûts

Impacts socioculturels

Impacts écologiques

Cycle de l'eau/ ruissellement

Sols

Biodiversité: végétale, animale

6.2 Impacts hors site que la Technologie a montrés

6.4 Analyse coûts-bénéfices

Quels sont les bénéfices comparativement aux coûts de mise en place (du point de vue des exploitants des terres)?

Quels sont les bénéfices comparativement aux coûts d'entretien récurrents (du point de vue des exploitants des terres)?

6.5 Adoption de la Technologie

Si disponible, quantifiez (nombre de ménages et/ou superficie couverte):

2820

Parmi tous ceux qui ont adopté la Technologie, combien d'entre eux l'ont fait spontanément, à savoir sans recevoir aucune incitation matérielle ou aucun paiement?

• 10-50%

Commentaires:

70% of land user families have adopted the Technology with external material support

1880 land user families have adopted the Technology with external material support

30% of land user families have adopted the Technology without any external material support

940 land user families have adopted the Technology without any external material support

There is a moderate trend towards spontaneous adoption of the Technology

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
Increased vegetation coverage and fruit and fodder production How can they be sustained / enhanced? Continuous maintenance of the structure.
Reduced soil erosion and increased soil moisture How can they be sustained / enhanced? Continuous maintenance of the structure.
Increased spring discharges downstream How can they be sustained / enhanced? Continuous maintenance of the structure.

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Decreased slope length, reduced runoff amount and velocity and soil erosion How can they be sustained / enhanced? Maintenance of bunds and runoff harvesting ditch.
Increase in rainwater harvesting, soil moisture and groundwater recharge How can they be sustained / enhanced? Maintenance of bunds and runoff harvesting ditch.
Increase in fruit and fodder production How can they be sustained / enhanced? Proper agronomic management
Reduced maintenance requirement compared to bunds made of soils How can they be sustained / enhanced? No action needed, as is inherent to technology

6.8 Faiblesses/ inconvénients/ risques de la Technologie et moyens de les surmonter

Faiblesses/ inconvénients/ risques du point de vue de l’exploitant des terres	Comment peuvent-ils être surmontés?
Damage to structures constructed at foot slopes if the hillside is not well conserved	Conserve the upper catchment first.
Increase labour requirement	Mass mobilization and/or increased incentives to households. Reducing the size of the structure.

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
Poor design approach (the same diameter and spacing for different slope ranges)	Improve the design approach.
Increased labour demand	Mass mobilization and improving the design.
Reduced farm land	Increasing the spacing and reducing the dimension of bunds without compromising their effectiveness.

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Staff members of the Kilte Awlaelo Wereda Office of Agriculture and Rural Development

Titre, auteur, année, ISBN:

Carucci, V. (2000). Guidelines on Water Harvesting and Soil Conservation for Moisture Deficit Areas in Ethiopia:the productive use of water and soil. First draft manual for trainers, Addis Ababa, Ethiopia.

Titre, auteur, année, ISBN:

Lakew, D., Carucci, V., Asrat, W. and Yitayew, A. (2005). Community Based Participatory Watershed Development: A guideline. Part I, first edition, Ministry of Agriculture and Rural Development, Addis Ababa, Ethiopia.