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

1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)

2.1 Short description of the Technology

Definition of the Technology:

Masonry dam in seasonal watercourse or river that stores water in the sand which accumulates above it.

2.2 Detailed description of the Technology

Description:

The dams are usually constructed where there is a rock bar in the river bed. The dam wall is raised 1.5 - 2.0 M above the level of sand.They fill up quickly with sand in which water is stored. The sand reduces the rate of evaporation and about 30% of the volume can store water for use in the dry season. If the dam is well constructed, maintenance is minimal. The dams are especially useful in semi-arid areas with catchments that provides plenty of coarse sand to fill up the reservoir.

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:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through projects/ external interventions

Comments (type of project, etc.):

Introduced in semi arid regions of kenya by the colonial government to increase water availabilty during the dry period through construction of masonary barrier across ephemeral rivers.

3.1 Main purpose(s) of the Technology

• adapt to climate change/ extremes and its impacts

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

Comments:

Major land use problems (compiler’s opinion): Semi-arid conditions with frequent failure of rains and experience water availabilty problems during dry period. High incidence of both on-farm soil erosion.

Major land use problems (land users’ perception): drought , insufficient rains, water scacity.

Number of growing seasons per year: 2
Longest growing period in days: 60 Longest growing period from month to month: Oct - JanSecond longest growing period in days: 58 Second longest growing period from month to month: Mar - May

3.5 SLM group to which the Technology belongs

• water harvesting

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

Comments:

Main type of degradation addressed: Wr: riverbank erosion

Secondary types of degradation addressed: Wg: gully erosion / gullying

Main causes of degradation: other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (Semi-arid climate)

Secondary causes of degradation: deforestation / removal of natural vegetation (incl. forest fires), over-exploitation of vegetation for domestic use (reduced infiltration and drying of springs), overgrazing, poverty / wealth (Lack of captial), education, access to knowledge and support services (Lack of knowledge - incidence of water borne dieseases)

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Kenya shillings

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

78.0

4.3 Establishment activities

	Activity	Timing (season)
1.	Digging out riverbed to reach rock bar	dryseason
2.	Laying concrete foundation	dryseason
3.	collection of materials (rocks, sand)	dryseason
4.	construction of dam and wing walls	dryseason

4.4 Costs and inputs needed for establishment

Comments:

Duration of establishment phase: 24 month(s)

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	inspection of dam for leakages	after the rains/each cropping season

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

Comments:

depth of the foundation, valley width.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

depth of foundation trench to the rock bar, the width of the river valley and the height of the banks.

5.1 Climate

5.2 Topography

Comments and further specifications on topography:

Slopes on average: Also gentle

Lanforms: In riverbeads

5.3 Soils

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil depth on average: Most areas have shallow soils with unweathered rocks.

Soil fertility is low

Soil drainage / infiltration is medium and soils are prone to surface sealing

Soil water storage capacity is low - medium

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Population density: 10-50 persons/km2

Annual population growth: 2% - 3%

1% of the land users are rich and own 5% of the land.
30% of the land users are average wealthy and own 35% of the land.
55% of the land users are poor and own 45% of the land.
14% of the land users are poor and own 15% of the land.

Off-farm income specification: A large proportion of the adult male population is working outside the district

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

Land ownership:

• individual, not titled
• individual, titled

Land use rights:

• individual

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

• > 50%

If available, quantify (no. of households and/ or area covered):

23000 Households in an area of 200 sq km

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

• 0-10%

Comments:

70% of land user families have adopted the Technology.

23000 land user families have adopted the Technology with external material support

Comments on acceptance with external material support: survey results

Comments on spontaneous adoption: estimates

There is a moderate trend towards spontaneous adoption of the Technology

Comments on adoption trend: self help groups have started pooling together their resources for implementation of the technology especially in areas where there has never been an NGO or such a project.

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

"Where there is no water" SASOL and Maji na Ufanisi 1999

Available from where? Costs?

Maji na Ufanisi Nairobi or SASOL Kitui