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

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

1.3 Conditions regarding the use of data documented through WOCAT

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

Yes

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?

No

2.1 Short description of the Technology

Definition of the Technology:

Embankment dams are built to retain rainwater without totally blocking the flow of water, enabling the irrigation of a part of the plain.

2.2 Detailed description of the Technology

Description:

The installation of earth embankment dams in lowland areas comprises the following elements: 1) a compacted earth embankment, 100 to 450 metres in length; 2) a side spillway built with rubble or cyclopean concrete, 40 to 75 metres in length and connected to the embankment with lock walls; 3) a spillway stilling basin of loose stones; 4) dam height of up to five metres and a crest width of up to four metres; 5) a pond upstream of the embankment dug up to three to four metres deep for storing water throughout the dry season and, thereby, ensuring supplies for watering animals, market gardening and fish farming.

Embankment dams retain water in the basin for several months after the end of the rainy season, which can be used for watering livestock and crops off season; and they help raise the water table, which makes well water more easily accessible (at a depth of one to five metres). These dams are used for both controlled and free submersion.
The side of the embankment is about one metre higher than that of the side spillway. When the water level reaches the height of the side spillway, water flows down through the structure and continues along the riverbed on its normal route downstream. In-season rice growing is carried out both upstream and downstream of the dam. Upstream growers farming areas peripheral to the reservoir are advised to use varieties of floating rice or those that can withstand prolonged flooding. The seedlings for this kind of rice must be sown before the reservoir fills with water.
At the end of the growing season, the water is retained in the reservoir for watering animals and for fishing. Market gardening activities are carried out along the entire length of the river, with water being extracted from dug wells (sumps two to six metres deep).
In Mali, there are around 15 schemes in place in the circles of Sikasso, Kadiolo, Bougouni and Yanfolila, covering more than 1,000 hectares and benefiting 1,500 rural families. In these areas, more than 60% of rice growers are women. More than 100,000 head of cattle are watered each year from the reservoirs. The very large quantity of stored water considerably increases the potential to use land for vegetable and tree growing.

Local people formulate the requirement and negotiate with the commune on the investment programme; they identify the rules of access and set up the farming cooperatives and management bodies. The commune plans investments and assumes overall control of the construction work, delegates management to users, and validates the farming rules and oversees their correct application. Consultancies carry out the socio-economic, environmental and technical studies (scheme design, plans, models), draw up the invitation to tender document and support the tender selection process, and monitor and inspect works. Technical services oversee the application of technical and environmental standards and participate in ensuring sound financial practices (collection, financial control, public service concessions). Contractors carry out the construction work. The project team provides training (planning, social engineering, studies involving farmers, etc.), advisory support (organisation of users, formulation and validation of rules, area development plan, plan to develop and exploit value chains, selection of suitable crop varieties, management delegation procedures, procedures for securing land titles, etc.) and co-financing.
The users are divided up into management and maintenance teams and their respective responsibilities are clearly defined prior to the interim and final acceptance of works.

This type of scheme is effective in areas with good rainfall levels and in lowland areas where the water table is not very low. It is important to select lowland areas with the potential to store a substantial volume of water (topographic basins). This type of scheme works best in southern areas of Mali with 1,100 to 1,200 millimetres of precipitation per year.

2.3 Photos of the Technology

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

2.6 Date 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 projects/ external interventions

Comments (type of project, etc.):

Since 2003, by HELVETAS Swiss Intercooperation

3.1 Main purpose(s) of the Technology

• improve production
• reduce, prevent, restore land degradation

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

Land use mixed within the same land unit:

Yes

Specify mixed land use (crops/ grazing/ trees):

• Agro-pastoralism (incl. integrated crop-livestock)

Cropland

• Annual cropping

Number of growing seasons per year:

• 1

Specify:

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

Grazing land

Waterways, waterbodies, wetlands

• Ponds, dams

Comments:

Major land use problems (compiler’s opinion): aridification, loss of water
Livestock density: 1-10 LU /km2

3.4 Water supply

Water supply for the land on which the Technology is applied:

• mixed rainfed-irrigated

3.5 SLM group to which the Technology belongs

• irrigation management (incl. water supply, drainage)
• water diversion and drainage
• surface water management (spring, river, lakes, sea)

3.6 SLM measures comprising the Technology

structural measures

• S5: Dams, pans, ponds

3.7 Main types of land degradation addressed by the Technology

biological degradation

• Bc: reduction of vegetation cover

water degradation

• Ha: aridification
• Hs: change in quantity of surface water
• Hg: change in groundwater/aquifer level

Comments:

Main causes of degradation: over abstraction / excessive withdrawal of water (for irrigation, industry, etc.), droughts

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• reduce land degradation

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

CFA Franc

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

512.0

4.3 Establishment activities

4.5 Maintenance/ recurrent activities

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The cost of a scheme stands at around 40 million CFA francs (77838 Dollars) for between 10 to 80 hectares (0.5 to 4 million CFA francs per hectare (972-7780 Dollars)).

5.1 Climate

5.2 Topography

5.3 Soils

5.4 Water availability and quality

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Population density: < 10 persons/km2
Annual population growth: 2% - 3%
10% of the land users are rich.
50% of the land users are average wealthy.
30% of the land users are poor.
10% of the land users are very poor.

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Comments:

The irrigated land is allocated by the chief

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

6.2 Off-site impacts the Technology has shown

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

Climate-related extremes (disasters)

Meteorological disasters

Climatological disasters

Hydrological disasters

Other climate-related consequences

Other climate-related consequences

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

Comments:

There is a moderate trend towards spontaneous adoption of the Technology
In Mali, there are around 15 schemes in place in the circles of Sikasso, Kadiolo, Bougouni and Yanfolila, covering more than 1,000 hectares and benefiting 1,500 rural families. The technique has now been mastered by a number of local companies. No dam has failed in the last eight years.
The technology has also been successfully adopted in northern Côte d’Ivoire.

6.7 Strengths/ advantages/ opportunities of the Technology

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Manual of Good Practices in Small Scale Irrigation in the Sahel. Experiences from Mali. Published by GIZ in 2014.

Available from where? Costs?

http://star-www.giz.de/starweb/giz/pub/servlet.starweb

Title, author, year, ISBN:

Intercooperation, Sahel Delegation (2008): Les aménagements de bas-fonds dans le bassin cotonnier de Sikasso. Expérience du programme Jékasy. [Developing lowland areas in the Sikasso cotton-growing basin. The Jékasy programme’s experience.] Intercooperation, Sahel Delegation: Capitalisation des experiences du programme Jékasy en gestion des ressources naturelles et aménagements des bas-fonds. [Capitalising on the experiences of the Jékasy programme in managing natural resources and lowland schemes.] Rapport Collecte de données sur la valorisation des ouvrages réalisés dans le Pôle de Bougouni sur le financement APEL [Data collection report on developing the value of APEL-funded schemes carried out in the Bougouni Hub] – Bougouni, April 2013