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)

Manual of Good Practices in Small Scale Irrigation in the Sahel (GIZ )

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

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

1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

01/07/2012

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

Ja

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?

Nee

2.1 Short description of the Technology

Definition of the Technology:

The role of small dams with weirs is to raise the water table, expand rice growing areas and extend the availability of water in lowland areas to complete the agricultural cycle of lowland areas (rice and vegetable growing).

2.2 Detailed description of the Technology

Description:

Small dams are installed on minor river beds and are connected up to the riverbanks. Their above-ground dimensions are small, but trench depths can be quite substantial in the case of a subterranean dam two to three metres deep. Plastic sheeting is placed in the trench to stop the water flowing underground.
Weirs are low-level structures built in flat valleys as extensions of small dams. Dam walls are low in height, standing from 0.1 m to 1 m above ground level.

The underground section of the dam retains upstream waters. As a result, the ground absorbs water and moisture throughout the entire area affected by the dam. The above-ground section (a watertight wall equipped with outflow gates) discharges the upstream water. It has a weir running along the marigot. Downstream, a stilling basin is installed to prevent erosion caused by the falling water. Using the weir and outflow gates, the water level can be adjusted to the requirements of each rice growing stage. The water retained by a dam equipped with a weir cannot be conserved for long periods. The structure’s main role is to provide water to meet the needs of the rainy-season crops. Even though the trenches are deep and the plastic sheeting prevents underground water dissipation, weirs can help to ensure ground waters are well recharged. This is why farmers should wait before digging wells to extract water for vegetable growing.

Local people formulate the requirement and negotiate with the commune on the investment programme, identify the rules of access and set up the farming cooperatives and management bodies, provide materials and unskilled labour during construction, and undertake small-scale maintenance work. The commune plans investments and assumes overall control of the construction work, delegates management to users, validates the farming rules and oversees their correct application, and undertakes major repairs. 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.) and advisory support (organisation of users, formulation and validation of rules, area development plan, plan to develop and exploit value chains).
The scheme can remain functional for up to 20 years provided it is rigorously maintained. The users are divided up into management and maintenance teams and their respective responsibilities are clearly defined.

More than 120 schemes with an average area of 20 hectares were built between 1998 and 2012. These schemes cover an area of more than 2,400 hectares and directly benefit over 15,000 families. The low cost combined with quick returns makes this type of intervention suitable for poor communities and local authorities. These structures can also be installed in dry areas. In these areas, it is essential from the outset that anti-erosion measures are put in place to manage the risk of sand encroachment.

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 1998, through Helvetas Swiss Intercooperation

3.1 Main purpose(s) of the Technology

• improve production

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

Comments:

Major land use problems (compiler’s opinion): water loss, aridification, low water table

3.3 Further information about land use

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

• mixed rainfed-irrigated

Number of growing seasons per year:

• 1

Specify:

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

Livestock density (if relevant):

1-10 LU /km2

3.4 SLM group to which the Technology belongs

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

3.5 Spread of the Technology

Specify the spread of the Technology:

• evenly spread over an area

If the Technology is evenly spread over an area, indicate approximate area covered:

• 10-100 km2

Comments:

More than 120 schemes with an average area of 20 hectares were built between 1998 and 2012. These schemes cover an area of more than 2,400 hectares and directly benefit over 15,000 families.

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

Comments:

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

3.8 Prevention, reduction, or restoration of land degradation

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

• prevent land degradation
• reduce land degradation

4.2 Technical specifications/ explanations of technical drawing

Technical knowledge required for field staff / advisors: high
Technical knowledge required for land users: low
Main technical functions: increase of infiltration, increase / maintain water stored in soil, increase of groundwater level / recharge of groundwater, water harvesting / increase water supply, water spreading

Dam/ pan/ pond
Height of bunds/banks/others (m): 1

4.3 General information regarding the calculation of inputs and costs

other/ national currency (specify):

CFA Franc

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

517.0

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	It is in community-led planning initiatives that the request for a lowland development scheme takes shape.	Structural
2.	The request is analysed (in consultation with the client community) to ascertain the socio-economic gains for the beneficiaries, the strengths and development potential of the area, and the motivation levels of the actors involved.	Structural
3.	The results are summarised in a report on the ideal development scenarios put forward by local people. Results are fed back to the community at a public meeting	Structural
4.	the findings of the technical diagnostic exercise are developed as a 3D model	Structural
5.	The consultant then moves on to performing economic and financial analyses, which will con- firm the cost effectiveness of the scheme	Structural
6.	A funding agreement is signed by the commune, farmers and project team	Structural

4.5 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Other	total construction		1.0	48703.0	48703.0
Total costs for establishment of the Technology					48703.0

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	The design consultancy conducts ongoing supervision of the works to ensure that the standards laid down in the technical dossier are adhered to. It is contractually bound to the commune through a monitoring and supervision contract	Structural
2.	public administration undertakes sporadic inspections to ensure relevant laws are respected	Structural

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The cost of installing these schemes ranges from 5 to 25 million CFA francs (9740-48703 Dollar). With this sum, it is possible to irrigate between 2 and 50 hectares. The cost per hectare stands at around 0.5 to 2 million CFA francs (947-3897 Dollar).

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 owned or leased 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

Soil

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

	Season	Type of climatic change/ extreme	How does the Technology cope with it?
annual temperature		increase	well

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	well
local windstorm	well

Climatological disasters

	How does the Technology cope with it?
drought	well

Hydrological disasters

	How does the Technology cope with it?
general (river) flood	well

Other climate-related consequences

Other climate-related consequences

	How does the Technology cope with it?
reduced growing period	well

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)?

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
The scheme has enabled previously irrigable areas to be rehabilitated and extended. Farming yields have doubled, or even tripled, due to the availability of water supplies and the technical support delivered post-build. The water table has risen (wells no longer dry up).
The effect on rice-growing areas is immediate: the retained water allows the agricultural crop cycle to be completed more easily.
Several operational scenarios are being implemented (a second and, in some cases, a third growing cycle has been made possible). Sizeable vegetable crops have been produced. Watering livestock is now easier and the lowland pastures are more abundant.
At the community level, larger revenues have been generated. The local population is busier throughout the year, which reduces outmigration, particularly among young people.
These schemes are simple and low cost. Most local contractors are fully competent in the installation techniques and high-tech equipment is not required.

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

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
It is important to make it clear to farmers that the water held in these small dam schemes cannot be stored throughout the dry season.	To avoid misunderstandings, users should be heavily involved in the design of the scheme.

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Intercooperation (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]

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:

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