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

Nom du projet qui a facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Water and Land Resource Centre Project (WLRC)

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

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

Oui

1.4 Déclaration sur la durabilité de la Technologie décrite

Est-ce que la Technologie décrite ici pose problème par rapport à la dégradation des terres, de telle sorte qu'elle ne peut pas être déclarée comme étant une technologie de gestion durable des terres?

Non

1.5 Référence au(x) questionnaire(s) sur les Approches de GDT

2.1 Courte description de la Technologie

Définition de la Technologie:

Gully erosion management is the application of combination of practices to control excess or concentrated runoff generation in the gully upstream catchment area, divert excess runoff upstream of gully heads and control further development of gully using appropriate structural and vegetative measures in the head, bed and sides of the gully and eventually convert into productive land through the consultation and involvement of local community.

2.2 Description détaillée de la Technologie

Description:

Gully erosion occurs on cultivated and grazing/pasture lands. Gully erosion management is a practice aimed to rehabilitate and protect further development of gullies and change into productive land. It involves both runoff management and erosion control activities. Gully management and treatment is different at upstream catchment area, gully head and gully section. Proper land management practices and slope treatment measures such as terraces, infiltration ditches and grass or shrub hedgerows are taking place on upstream catchment of the gully in order to reduce the rate of surface runoff. The excess runoff above the gully head is safely drained using cutoff drains into natural or properly vegetated waterways in order to reduce the surface water entering into the gully and protect the constructed physical and biological measures being washed away. Before treating gully sections, for the purpose of stability of structures and quick healing, the gully should be reshaped and planted with grass sod. Gully wall reshaping is cutting off steep slopes of active gully flanks in to gentle slope of minimum at 45% slope, up to two-third of the total depth of the gully and constructing small trenches along contours for re-vegetating slanted part of the gully walls and beds. If the gully is wide and has meandering nature with huge accumulation of runoff flowing down, it requires constructing of retaining walls, to protect displaced (not yet stabilized) soils and soil materials and the sidewalls of the reshaped gully. Stabilization of gully sections involves the use of structural and vegetative measures in the head, floor and side of the gully. The construction of physical structures inside the gully section is followed by establishment of biological measures.

Purposes of gully erosion management are: 1) rehabilitate the land damaged due to gully erosion, 2) prevent further expansion and development of gully erosion, and 3) convert the land lost by gully erosion to productive land.

Gully erosion management begins with assessment and mapping of gully erosion that helps to have an overview of erosion, to document extent of damage, to identify the nature and causes of gully formation, and gives relevant information to design appropriate measures. At establishment stage, gully management requires: catchment treatment using different land treatment measures; runoff diversion by cutoff drain; and stabilization of gully sections by physical structures and vegetative measures. Stones for the construction of terraces, cutoff drains and waterways are required. Depending on the nature of gully and available material for construction, either stones, sand bags, brush woods, bamboo mat, gabion or concrete (sand, gravel and cement) are needed for constructing check-dams in a gully section. Different tree/shrub seedlings, grass cuttings, and seedlings of fruit trees are required to reinforce and stabilize the gully sections. The respective labor requirement for stone collection, construction of retaining wall, and gully reshaping is 0.5m3/person day, 5m/person day, and 1m3/person day. Approximately 0.25, 0.50, 0.50, 0.50 , and 1.0 m3/person day is required to construct gabion, loose stone, arc weir, sand bag, and bamboo mat check-dams respectively. About 3.0 m/person day is needed to construct brushwood check dams. The treated gullies should be checked regularly. The maintenance requirement is closely monitored and immediate repair is essential to avoid further damage and eventual collapse of structures. The inputs important for maintenance include stones or other materials for check dams, seedlings to replant areas covered with non-survived seedlings.

Gully erosion is prevalent in areas where excess runoff occurs in high rainfall areas associated with moderate to high erodible soils. It occurs in range of wet highland to moist Kolla areas where annual rainfall exceeds 900mm. Its occurrence is more frequent in heavy clay soils (Vertisols) characterized by low infiltration and in clay soils (like Nitosols) characterized by low organic matter. Often, gully formation occurs on overgrazed pasture lands and inappropriately managed crop lands. Gully erosion control requires mobilization of high input or materials and labor. Larger gullies need to be rehabilitated and treated through community labor mobilization. Subsequent maintenance activities, monitoring and benefit sharing should be made by the user groups who are entitled to utilize the benefits.

The living condition depends on subsistence crop-livestock mixed farming. On average households have 5-6 family size. Crop production is meant for home consumption with small surplus for local market. The services related to water supply, energy supply, and infrastructure are low. Besides it is an asset, animals often used to cope shocks during drought periods.

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: :

• au cours d'expérimentations / de recherches
• par le biais de projets/ d'interventions extérieures

Commentaires (type de projet, etc.) :

Since gully erosion management requires combination of practices, many actors mainly research, local development actors, community, and project are involved in the development of the technology

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): Land degradation due to different forms of soil erosion and nutrient depletion, overgrazing, shortage of pasture lands and its low productivity, excessive and inappropriate construction of traditional ditches, and increased pressure on trees for the purpose of fuel wood and timber.
Major land use problems (land users’ perception): Soil erosion and soil nutrient depletion, shortage of cultivated land, shortage of grazing land and wood for fuel wood
The type of grazing is often free grazing on communal grazing lands/pasture, supplemented with crop residues and zero grazing combined with improved forages

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: 220, Longest growing period from month to month: May to December; Second longest growing period in days: 180, Second longest growing period from month to month: June to November

Densité d'élevage/ chargement (si pertinent):

> 100 LU /km2

3.4 Groupe de GDT auquel appartient la Technologie

• fermeture de zones (arrêt de tout usage, appui à la réhabilitation)

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:

Type of vegetative measures: aligned: -contour, aligned: -along boundary

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires), over-exploitation of vegetation for domestic use, overgrazing, Heavy / extreme rainfall (intensity/amounts), population pressure
Secondary causes of degradation: soil management, crop management (annual, perennial, tree/shrub), urbanisation and infrastructure development (Urbanization and infrastructure development induced excessive compaction, unprotected drainage systems and lead to gully formation), floods, land tenure (Land under undefined or communal use of grazing lands are subject to mismanagement that result in gully formation), poverty / wealth

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

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

A reshaped gully section treated with an integrated gully control measures including check dams made of loose stone and wooden and vegetative tree/shrub and grass hedgerows planted on the sides of gullies.
Location: Debre Mewi Learning Watershed. Yilmana Densa/West Gojam/Amhara Region
Date: 6/27/2016

Technical knowledge required for field staff / advisors: high (It requires knowledge of peak runoff and runoff management and skills to integrate different measures)
Technical knowledge required for land users: high (It needs skills to construct physical measures, and regular monitoring and maintenance of practices. The users must know and understand the growth nature and harvesting stage tree/shrub, grass species)

Main technical functions: control of concentrated runoff: impede / retard, control of concentrated runoff: drain / divert, reduction of slope angle
Secondary technical functions: reduction of slope length, improvement of ground cover, stabilisation of soil (eg by tree roots against land slides), increase of infiltration

Aligned: -contour
Vegetative material: T : trees / shrubs, G : grass
Number of plants per (ha): 2600
Spacing between rows / strips / blocks (m): 2-3
Vertical interval within rows / strips / blocks (m): 0.5-1.0
Width within rows / strips / blocks (m): 0.5

Aligned: -graded strips
Vegetative material: T : trees / shrubs

Aligned: -along boundary
Number of plants per (ha): 200
Vertical interval within rows / strips / blocks (m): 1
Width within rows / strips / blocks (m): 1

In blocks
Vegetative material: T : trees / shrubs

Vegetative measure: Alinged along side wall of gully
Vegetative material: T : trees / shrubs
Number of plants per (ha): 6800
Spacing between rows / strips / blocks (m): 2-3.0
Vertical interval within rows / strips / blocks (m): 0.5-1.0
Width within rows / strips / blocks (m): 0.5

Vegetative measure: Aligned along side wall of gully
Vegetative material: T : trees / shrubs
Number of plants per (ha): 4800
Spacing between rows / strips / blocks (m): 2-3.0
Vertical interval within rows / strips / blocks (m): 0.5
Width within rows / strips / blocks (m): 0.5
Vegetative measure: Vegetative material: T : trees / shrubs
Trees/ shrubs species: Susbania sesban, Acacia decurrence, treelucern, Acacia saligna
Grass species: Elphant grass, Sudan grass
Slope (which determines the spacing indicated above): 20-30%%
If the original slope has changed as a result of the Technology, the slope today is (see figure below): 18-25%%
Gradient along the rows / strips: 0.5%

Diversion ditch/ drainage
Depth of ditches/pits/dams (m): 0.3-0.7
Width of ditches/pits/dams (m): 1.2-2.8
Length of ditches/pits/dams (m): 100-250

Waterway
Depth of ditches/pits/dams (m): 0.3
Width of ditches/pits/dams (m): 1.5-2.0

Structural measure: Check dams
Vertical interval between structures (m): 1
Spacing between structures (m): 10-15
Height of bunds/banks/others (m): 1-1.5
Width of bunds/banks/others (m): 1.5-3.5

Construction material (earth): Excavated soil
Construction material (stone): Loose stones for check dam
Construction material (wood): Brush wood for check dam
Slope (which determines the spacing indicated above): 10-18%
If the original slope has changed as a result of the Technology, the slope today is: 8-12%
Vegetation is used for stabilisation of structures.

4.3 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

ETB

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

20,0

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Seedling preparation	Végétale	January-June
2.	Seedling Transportation	Végétale	June-July
3.	Grass split transportation	Végétale	June -July
4.	Plantation of biological measures inside the gully	Végétale	July
5.	Surveying	Structurel	Dry season
6.	Reshaping of gully	Structurel	Dry season
7.	Construction of cutoff drains	Structurel	Dry season
8.	Construction of waterways	Structurel	Dry season
9.	Construction of stone check dams	Structurel	Dry season

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	8319,0	8319,0	99,0
Equipements	animal traction	ha	1,0	9,0	9,0	100,0
Equipements	tools	ha	1,0	901,8	901,8	50,0
Matériel végétal	grass	ha	1,0	20,0	20,0
Matériel végétal	seeds	ha	1,0	24,0	24,0
Matériel végétal	seedlings	ha	1,0	63,45	63,45
Engrais et biocides	compost/manure	ha	1,0	15,86	15,86
Matériaux de construction	stone	ha	1,0	1405,0	1405,0	91,0
Matériaux de construction	wood	ha	1,0	27,6	27,6
Matériaux de construction	earth	ha	1,0	91,2	91,2
Coût total de mise en place de la Technologie					10876,91

Commentaires:

Duration of establishment phase: 15 month(s)

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Seedling preparation	Végétale	January-June
2.	Seedling and grass split transportation	Végétale	July
3.	Replanting seedlings and grass splits	Végétale	July
4.	Maintenance of cutoff drains/waterways	Structurel	Dry season (Jan-Apr)
5.	Maintenance of check dams	Structurel	Dry season (Jan-Apr)

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	902,0	902,0	67,0
Equipements	animal traction	ha	1,0	4,5	4,5
Matériel végétal	grass	ha	1,0	10,3	10,3
Matériel végétal	seedlings	ha	1,0	33,0	33,0
Engrais et biocides	compost/manure	ha	1,0	8,5	8,5
Matériaux de construction	stone	ha	1,0	50,0	50,0	41,0
Matériaux de construction	wood	ha	1,0	14,4	14,4
Matériaux de construction	earth	ha	1,0	45,6	45,6
Coût total d'entretien de la Technologie					1068,3

Commentaires:

The costs are calculated on hectare basis

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

The costs for gully erosion management is dependent upon labor, material and transport costs, workability of the soil and maintenance costs.

5.1 Climat

5.2 Topographie

5.3 Sols

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
Difference in the involvement of women and men: Women are involved in collecting stones and assisting men on heavy works
Population density: 200-500 persons/km2
Annual population growth: 2% - 3%
80% of the land users are average wealthy.
20% of the land users are poor.
Some land users involve in seasonal labor in towns and sell charcoal

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 de l’eau:

• accès libre (non organisé)
• communautaire (organisé)

Commentaires:

Land use rights on crop land is individual while on grazing lands it is communal either unorganized or organized in some cases. Water is open accessible in most cases except organized communal utilization for some developed drinking water sources.

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

6.3 Exposition et sensibilité de la Technologie aux changements progressifs et aux évènements extrêmes/catastrophes liés au climat (telles que perçues par les exploitants des terres)

Extrêmes climatiques (catastrophes)

Catastrophes météorologiques

	Comment la Technologie fait-elle face à cela?
pluie torrentielle locale	pas bien

Catastrophes climatiques

	Comment la Technologie fait-elle face à cela?
sécheresse	bien

Catastrophes hydrologiques

	Comment la Technologie fait-elle face à cela?
inondation générale (rivière)	pas bien

Commentaires:

Gully erosion management involves combination of biological and physical measures. Strong structural measures and upstream runoff management practices should be applied to tolerate flooding.

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)?

Commentaires:

The short term economic benefits of management of gully erosion include grass and fodder production for livestock feed. While the long term benefits may include product diversification like fruit, fodder, and grass production.

6.5 Adoption de la Technologie

Commentaires:

About 3-5% of the total area of watersheds are treated with gully management. Gullies formed on crop lands and communal grazing lands are management collectively by the community labor with external material support such as gabion and seedlings
Gully management is beyond the capacity of land users. So, they are often supported with seedlings and gabions for large gullies
There is a little trend towards spontaneous adoption of the Technology
Land users show interest and motivation by delineating gully damage areas and control free grazing. They also do fencing with external support for nails and seedlings.

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
It increases fodder production
It protects further expansion and damage of settlement areas and infrastructures
It increases the flow of streams

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Gully erosion management provides an immediate fodder for cut-and-carry grazing system and encourages zero grazing
It controls erosion and sediment transport as well it increases stream flows to downstream and subsequently changed to productive area
It reduces conflict among adjacent land holders due to formation of gullies
It does not only reduce degradation but also stabilize the soil, water and vegetation system in the area
It increases the awareness level of farmers about land degradation and its causes

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?
It is labor intensive and sometimes harbor rodents and pests	Apply traditional collective action mechanisms

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
It requires high labor for regular monitoring and maintenance of structures and protect from damage by excessive runoff	Establish by laws and procedures for collective actions among the user groups

7.1 Méthodes/ sources d'information

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Gully Rehabilitation: What Does it Costs to Heal Gullies and Make Productive? WLRC Brief No. 3. June 2015

Disponible à partir d'où? Coût?

www.wlrc-eth.org