1.2 Detalhes do contato das pessoas capacitadas e instituições envolvidas na avaliação e documentação da tecnologia

Nome do projeto que facilitou a documentação/avaliação da Tecnologia (se relevante)

Good Practices in Soil and Water Conservation - A contribution to adaptation and farmers ́ resilience towards climate change in the Sahel (GIZ)

Nome da(s) instituição(ões) que facilitou(ram) a documentação/ avaliação da Tecnologia (se relevante)

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH (GIZ) - Alemanha

1.3 Condições em relação ao uso da informação documentada através de WOCAT

Quando os dados foram compilados (no campo)?

01/07/2012

O/a compilador/a e a(s) pessoa(s) capacitada(s) aceitam as condições relativas ao uso de dados documentados através da WOCAT:

Sim

1.4 Declaração de sustentabilidade da tecnologia descrita

A tecnologia descrita aqui é problemática em relação a degradação da terra de forma que não pode ser declarada uma tecnologia de gestão sustentável de terra?

Não

2.1 Descrição curta da tecnologia

Definição da tecnologia:

Permeable rock dikes are erosion control structures to slow down runoff

2.2 Descrição detalhada da tecnologia

Descrição:

Permeable rock dikes are erosion control structures built along the natural contour of the land and designed to slow down runoff. They are built between 30 and 50 cm high and twice or three times as wide as they are high. They are made with different-sized stones and rocks, and the crest of the dike is horizontal. There are two main types of permeable rock dike: those without a filter layer, which are suitable for flat land with no gully erosion and those with a filter layer suited to land with heavy runoff.

Because of the way it is constructed, it dissipates the erosive force of the water. Sediment builds up behind it, resulting in the formation of terraces. It also increases the infiltration of surface water into the soil. The retention of water and fertile sediment by the dikes facilitates the development of natural vegetation along the structure. Grass and bush seeds are trapped by the dikes, favouring the spontaneous growth of natural vegetation, which contributes to restoring biodiversity and provides a habitat for wildlife. Good tree and grass cover developed along the dikes contributes to lowering soil temperature and reducing wind erosion along the entire length of the structure.
The reduction in runoff downstream of the dikes contributes to reducing alluvial deposits in the valleys further downstream. Watershed development with permeable rock dikes reduces siltation and gully erosion.
Permeable rock dikes are designed for use on cropland, but can also be used on forest/rangeland. They are recommended for ecological units with gravely and sandy-clayey soils and pediments. They can also be used to fill in small rills.
Studies conducted in the PATECORE area show that plots with permeable rock dikes averaged sorghum yields of 795 kg compared with 576 kg on control plots, which means that yields were 38% higher on improved plots. The production of straw for livestock increases in the same proportion as grain output.

With some upkeep, permeable rock dikes last at least 20 years. Before the rainy season starts, any stones dislodged by animals must be replaced. During the rainy season, the water can wear gaps in the dikes, which must be repaired immediately. The stability of the dikes can be reinforced by active revegetation (by sowing grass or planting trees). Without direct sowing, natural vegetation develops along the dikes after several years.

From the point of view of climate change adaptation, permeable rock dikes mitigate the effects of variations in rainfall. They are appropriate in wet period with heavy rain and violent downpours: permeable rock dikes constructed on the upper edge of the plot as a protective measure and a means of improving infiltration, protect land at risk from erosion. They are also appropriate during dry periods as they stop or slow down the flow of water. Permeable rock dikes improve infiltration and therefore increase and prolong the availability of water for crops. The permeable rock dike differs from the contour stone bund in that it is bigger in size, is constructed with various layers of stones and is designed to control stronger water flow. For this reason, such dikes are often constructed up-stream of stone bunds to dissipate the force of the water flowing from the plateaux and slopes.

2.3 Fotos da tecnologia

2.5 País/região/locais onde a tecnologia foi aplicada e que estão cobertos nesta avaliação

2.6 Data da implementação

Caso o ano exato seja desconhecido, indique a data aproximada:

• 10-50 anos atrás

2.7 Introdução da tecnologia

Especifique como a tecnologia foi introduzida:

• através de projetos/intervenções externas

Comentários (tipos de projeto, etc.):

developed, implemented and disseminated as part of projects and programmes undertaken from the 1980s onwards to combat desertification and improve natural resource management. Implemented by GIZ (German Federal Enterprise for International Cooperation), and PATECORE (project for land development and resource conservation in Plateau Central)

3.1 Principal/principais finalidade(s) da tecnologia

• Reduz, previne, recupera a degradação do solo

3.2 Tipo(s) atualizado(s) de uso da terra onde a tecnologia foi aplicada

Comentários:

Major land use problems (compiler’s opinion): surface runoff, soil erosion by water and wind, fertility decline
Constraints of common grazing land
Constraints of forested government-owned land or commons

3.3 Mais informações sobre o uso da terra

Número de estações de cultivo por ano:

• 1

Especifique:

Longest growing period in days: 120, Longest growing period from month to month: August to October

3.4 Grupo de GST ao qual pertence a tecnologia

• Medidas de curva de nível

3.6 Medidas de GST contendo a tecnologia

3.7 Principais tipos de degradação da terra abordados pela tecnologia

Comentários:

Main causes of degradation: crop management (annual, perennial, tree/shrub) (Unadapted landuse methods, reduced or abandoned fallow periods), floods, droughts, population pressure (rapidly growing population increasing pressure on land), land tenure (insecure access to land)

3.8 Redução, prevenção ou recuperação da degradação do solo

Especifique o objetivo da tecnologia em relação a degradação da terra:

• Reduzir a degradação do solo
• Recuperar/reabilitar solo severamente degradado

4.1 Desenho técnico da tecnologia

4.2 Especificações técnicas/ explicações do desenho técnico

Permeable rock dikes are built between 30 and 50 cm high and twice or three times as wide as they are high. They are made with different-sized stones and rocks, and the crest of the dike is horizontal. There are two main types of permeable rock dike: those without a filter layer, which are suitable for flat land with no gully erosion and those with a filter layer suited to land with heavy runoff.

Technical knowledge required for field staff / advisors: moderate
Technical knowledge required for land users: low
Main technical functions: control of dispersed runoff: retain / trap, control of dispersed runoff: impede / retard, control of concentrated runoff: retain / trap, control of concentrated runoff: impede / retard, control of concentrated runoff: drain / divert, reduction of slope angle, improvement of ground cover, increase in nutrient availability (supply, recycling,…), increase of infiltration, increase / maintain water stored in soil, water harvesting / increase water supply, sediment retention / trapping, sediment harvesting
Secondary technical functions: stabilisation of soil (eg by tree roots against land slides), increase in organic matter, increase of groundwater level / recharge of groundwater, reduction in wind speed, promotion of vegetation species and varieties (quality, eg palatable fodder)

Bund/ bank: graded
Height of bunds/banks/others (m): 0.3-0.5
Width of bunds/banks/others (m): 1.5

4.4 Atividades de implantação

	Atividade	Tipo de medida	Periodicidade
1.	levelling and marking out the contour line	Estrutural
2.	collecting stones and loading them onto carts	Estrutural
3.	transporting the stones by cart	Estrutural
4.	building the dikes	Estrutural
5.	applying manure	Estrutural

4.6 Atividades recorrentes/manutenção

	Atividade	Tipo de medida	Periodicidade/frequência
1.	Before the rainy season starts, any stones dislodged by animals must be replaced.	Estrutural
2.	During the rainy season, the water can wear gaps in the dikes, which must be repaired immediately.	Estrutural

4.7 Custos e entradas necessárias pata a manutenção/atividades recorrentes (por ano)

Comentários:

Machinery/ tools: pickaxes, shovels, wheelbarrows, water-tube level, etc.

4.8 Fatores mais importantes que afetam os custos

Descreva os fatores mais determinantes que afetam os custos:

The exact cost of constructing permeable rock dikes per hectare depends on the distance of the site from the quarry, the inclination of the terrain, which determines the spacing between the dikes, and the actual amount of stones transported in each lorryload or cartload. Supply of quarry rock/stones: 48 m3 for 200 m of dike.
Labour: 60 man-days per ha
• levelling and marking out the contour line: 1 man-day
• collecting stones and loading them onto carts:
20 man-days
• transporting the stones by cart: 20 man-days
• building the dikes: 19 man-days
• applying manure.
Transportation by cart:
• 20 cartloads of stones
• 20 cartloads of manure (if used).
Transportation by lorry:
• 11 lorryloads (skip loader – 4.5 m3 per load).
Other costs:
• equipment (pickaxes, shovels, wheelbarrows, water-tube level, etc.).

5.1 Clima

5.2 Topografia

5.3 Solos

5.4 Disponibilidade e qualidade de água

5.5 Biodiversidade

5.6 Características dos usuários da terra que utilizam a tecnologia

Indique outras características relevantes dos usuários da terra:

Population density: 10-50 persons/km2
Annual population growth: 3% - 4% (mostly poor households below poverty line).
Off-farm income specification: men migrate temporarily or permanently to cities for off-farm income

5.7 Média da área de terra própria ou arrendada por usuários da terra que utilizam a tecnologia

5.8 Propriedade de terra, direitos de uso da terra e de uso da água

Propriedade da terra:

• Estado

Direitos do uso da terra:

• Comunitário (organizado)

Direitos do uso da água:

• Comunitário (organizado)

Comentários:

traditional land use rights on fields, communal land on pasture and forest land

5.9 Acesso a serviços e infraestrutura

6.1 Impactos no local mostrados pela tecnologia

Impactos socioeconômicos

Produção

Renda e custos

Impactos socioculturais

Impactos ecológicos

Ciclo hídrico/escoamento

Solo

Biodiversidade: vegetação, animais

Clima e redução de riscos de desastre

6.2 Impactos externos mostrados pela tecnologia

6.3 Exposição e sensibilidade da tecnologia às mudanças climáticas graduais e extremos/desastres relacionados ao clima (conforme o ponto de vista dos usuários da terra)

Mudança climática gradual

Mudança climática gradual

	Estação do ano	Tipo de mudança climática/extremo	Como a tecnologia lida com isso?
Temperatura anual		aumento	bem

Extremos (desastres) relacionados ao clima

Desastres meteorológicos

	Como a tecnologia lida com isso?
Temporal local	bem
Tempestade de vento local	bem

Desastres climatológicos

	Como a tecnologia lida com isso?
Seca	bem

Desastres hidrológicos

	Como a tecnologia lida com isso?
Inundação geral (rio)	não bem

Outras consequências relacionadas ao clima

Outras consequências relacionadas ao clima

	Como a tecnologia lida com isso?
Período de crescimento reduzido	bem

6.4 Análise do custo-benefício

Como os benefícios se comparam aos custos de implantação (do ponto de vista dos usuários da terra)?

Como os benefícios se comparam aos custos recorrentes/de manutenção(do ponto de vista dos usuários da terra)?

6.5 Adoção da tecnologia

Comentários:

There is a little trend towards spontaneous adoption of the Technology
The technique’s potential for replication depends on the type of terrain and the availability of a supply of stones within a reasonable distance. The technique is very effective as a flood control measure and is relatively easy to learn. Farmers are able to implement the technique themselves after two days’ training. This technique can only be implemented with highly motivated groups and villages, with strong working and mobilisation capacities.

6.7 Pontos fortes/vantagens/oportunidades da tecnologia

Pontos fortes/vantagens/oportunidades na visão do/a compilador/a ou de outra pessoa capacitada
The retention of water and fertile sediment by the dikes facilitates the development of natural vegetation along the structure. Grass and bush seeds are trapped by the dikes, favouring the spontaneous growth of natural vegetation, which contributes to restoring biodiversity and provides a habitat for wildlife.
Studies conducted in the PATECORE area show that plots with permeable rock dikes averaged sorghum yields of 795 kg compared with 576 kg on control plots, which means that yields were 38% higher on improved plots. The production of straw for livestock increases in the same proportion as grain output.
The reduction in runoff downstream of the dikes contributes to reducing alluvial deposits in the valleys further downstream. Watershed development with permeable rock dikes reduces siltation and gully erosion.
The technique is very effective as a flood control measure and is relatively easy to learn. Farmers are able to implement the technique themselves after two days’ training.
With some upkeep, permeable rock dikes last at least 20 years.

6.8 Pontos fracos, desvantagens/riscos da tecnologia e formas de superá-los

Pontos fracos/vantagens/riscos na visão do/a compilador/a ou de outra pessoa capacitada	Como eles podem ser superados?
Permeable rock dikes are not as effective as contour stone bunds for the purpose of reforestation. This is because in the case of contour stone bunds, more linear metres are required per hectare than in the case of permeable rock dikes

7.1 Métodos/fontes de informação

7.2 Referências às publicações disponíveis

Título, autor, ano, ISBN:

Good Practices in Soil and Water Conservation. A contribution to adaptation and farmers´ resilience towards climate change in the Sahel. Published by GIZ in 2012.

Disponível de onde? Custos?

http://agriwaterpedia.info/wiki/Main_Page