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

Quand les données ont-elles été compilées (sur le terrain)?

11/01/2018

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

2.1 Courte description de la Technologie

Définition de la Technologie:

These are constructions stretching across the sand filled dry riverbed, down towards the impermeable floor of the riverbed. They are totally submerged into the ground. For example by fully covering after construction by sand. This are done along dry rivers with huge sand deposits, which has high yield potential and where water can be easily extracted. The aim is to raise groundwater tables and increase the storage capacity for water withdrawals.

2.2 Description détaillée de la Technologie

Description:

The technology is applied in northern rangeland of Isiolo County which is managed under communal management systems. The aim of technology to reduce pasture and water availability imbalances. The dimensions of sub-surface dam include: a length of water spread (103m),width of the dam (15m), width of water spread (18m), effective dam height (2m), volume of retained sand (103 x 0.5(15 +18) x0.5 x2.0 = 5098.50m3) and the volume of water that can be abstracted from the sand bed (25/100x 5098.50m3 = 1274.6.36m3).
The technology functions as underground water storage infrastructure and the typical activities include, excavation of top porous soil, excavation of sample pits within the excavated area, checking filtration rates of soil, compaction of soil on which dam liners are laid, smoothing the sharp liners along which the dam liners are laid, making grooves to anchor the dam liner, laying the dam liner, anchoring the dam liner with a mixture of cement, water proof and sand with water (motor) and finally drying of the motor and filling back of sand.
The development of Sub-Surface Dams (SSDs) was done through Cash for Work program where local labours comprising of 40-50 persons are engaged in excavation, compactions and developing the liners. Farm tools like jembe, panga, spades and human labour are required to develop the SSD. The technology improves water supply/availability, thereby extending the period of livestock grazing in areas where typically water is depleted before the pasture hence improves water access for livestock in ways that support wider management and utilization of the rangeland and as such strength the resilience of pastoralists to droughts. This effectively gives pastoral groups, an extra grazing time (typically 2 extra months), a period usually not too long to encourage land degradation through over-grazing but long enough to enable pastoralist utilize the remaining pasture in wet season grazing areas. In so doing, the technology enable balanced use of vast communal lands without livestock retreating to dry season grazing areas.
In the process of the landscape level participatory planning with the communities: i) they identified different challenges, including need for decommissioning certain water points that they consider are contributing to over grazing and also attracting other communities, hence drive frequent conflicts, secondly, ii) they mapped areas in the rangeland where there is mismatch between water and pasture availability, most of these areas are in wet season grazing areas. So the next discussion was on what strategic water infrastructures that will enable herders to graze for 2 -3 extra months to enable them utilize the grass before they migrate to the traditional dry season grazing areas. So by design, the technology should only yield water that can allow settling for those extra months, not longer to the detriment of the rangeland
The technology was instrumental in fostering both balanced utilization of land and strengthening sustainable use of the vast rangeland by ensuring that herders utilize available pastures in the wet seasons grazing areas before moving to dry seasons grazing areas. The water stored through the technology stays longer, in this case study, the water lasted for 5 months after the end of the rainy season .
The area receives bimodal rainfall, long rain in March-May and short rain in November-December. With changing seasons/climate, the dry seasons can last up to 1 year in case of rainfall failure. Typically, dry seasons are 6-7 months (May- November).
Normally, the water is depleted within 2 months after the rainy period. The technology is also cheap and easy to understand and construct (especially in areas with clay as the underlying impermeable material) with a possibility of the communities to be taught how to identify suitable site and the entire process of construction. However, in areas without clay soil, the excavation of clay and transportation can be labour intensive and expensive.

2.3 Photos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• par le biais de projets/ d'interventions extérieures

3.1 Principal(aux) objectif(s) de la Technologie

• améliorer la production
• réduire, prévenir, restaurer les terres dégradées
• s'adapter au changement et aux extrêmes climatiques et à leurs impacts
• atténuer le changement climatique et ses impacts
• créer un impact économique positif
• créer un impact social positif

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Commentaires:

Communal grazing area that is shared by 2 and more pastoral groups

3.3 Informations complémentaires sur l'utilisation des terres

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• pluvial

Densité d'élevage/ chargement (si pertinent):

Fluctuates, depending on seasons and pasture availability

3.4 Groupe de GDT auquel appartient la Technologie

• pastoralisme et gestion des pâturages

3.5 Diffusion de la Technologie

Spécifiez la diffusion de la Technologie:

• appliquée en des points spécifiques ou concentrée sur une petite surface

Commentaires:

Sub-Surface Dams are only suitable in areas along the river, with suitable density of sand deposits

3.6 Mesures de GDT constituant la Technologie

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Mismatch of pasture and water resources - there are areas where pastures are plenty but surface rain water is depleted earlier than pasture.

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:

• prévenir la dégradation des terres
• réduire la dégradation des terres

Commentaires:

The SSD technology increase water availability is period immediately after the rain, hence ensuring better pasture utilization and more sustainable use of land.

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

The SSD has initial excavation works. The construction of the SSD was constructed by 50 laborers. The area of excavation is subdivided into 45 square chambers of 4X2.3X2.2= 20.2M3 (not to scale). Each of the chambers were excavated by 5 laborers. The estimated time for excavation as per the plan was estimated to be five days. Excavation and transportation of the clay from the clay pit was estimated to take an approximate of five days while the compacting of the clay will follow one week later, and laying out of the concrete and refilling of the sand for another week. The liner will then be finally placed. In summary, the excavation of sand takes 5 days, and the excavation of clay soil takes another 5 days while concrete placing, compacting of clay as well as putting of liner and refilling of sand takes 10 days.

4.3 Informations générales sur le calcul des intrants et des coûts

Spécifiez la manière dont les coûts et les intrants ont été calculés:

• par entité de la Technologie

Indiquez la monnaie utilisée pour le calcul des coûts:

• dollars US

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Removing sand over dyke and man-days for excavating and transporting soil to dam site	Autres mesures	21 days for 45 casual labourers
2.	Building and compaction soil in dam wall	Structurel	3 days for 45 casual labourers
3.	Supplying water for compaction	Autres mesures	0.5 day for 45 casual labourers
4.	Back-filling sand on dam	Autres mesures	1 day for 45 casual labourers
5.	Supplying water for compacting clay in dam wall	Autres mesures	2 days for 45 casual labourers
6.	Compacting soil and placing liners	Autres mesures	12 days for 45 casual labourers

Commentaires:

The construction of SSD was done through “Cash for work” which is participatory process that involves community mobilization, identification of beneficiaries and formation of “Cash for work” committees, registrations and verification of beneficiaries and implementation/supervision of the work.

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	tools - jembe, spade etc.	pieces	80,0	5,33	426,4
Main d'œuvre	Removing sand over dyke and Man-days for excavating and transporting soil to dam site	per day	945,0	4,0	3780,0
Main d'œuvre	Building and compaction soil in dam wall	per day	135,0	4,0	540,0
Equipements	Supplying water for compaction	per day	22,5	4,0	90,0
Equipements	Back-filling sand on dam	per day	45,0	4,0	180,0
Equipements	Supplying water for compacting soil in dam wall	per day	90,0	4,0	360,0
Equipements	Compacting soil and placing liners	per day	540,0	4,0	2160,0
Coût total de mise en place de la Technologie					7536,4

Commentaires:

As stated, the cash for work approach means that people get paid 4 USD per day for working on SSD until completion. There are phases where people participated in preliminary phases in meetings and consultation without payments but the actual work was done on cash for work basis.

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Training of communities to manage and maintain the structures	Structurel	yearly

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 for site protection and maintenance of hygiene	per site	10,0	100,0	1000,0
Coût total d'entretien de la Technologie					1000,0

Commentaires:

Water User Associations on the sites are trained on the management of the structures on behalf of the community e.g. on the protection of structure and hygiene maintenance.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

Distance of the sub-surface dam from villages, extent of destruction by floods and human activities

5.1 Climat

5.2 Topographie

Indiquez si la Technologie est spécifiquement appliquée dans des:

• situations concaves

5.3 Sols

5.4 Disponibilité et qualité de l'eau

La salinité de l'eau est-elle un problème? :

Non

La zone est-elle inondée?

Non

5.5 Biodiversité

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

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:

• communauté/ village

Droits d’utilisation des terres:

• communautaire (organisé)

Droits d’utilisation de l’eau:

• communautaire (organisé)

5.9 Accès aux services et aux infrastructures

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Disponibilité et qualité de l'eau

Impacts écologiques

Réduction des risques de catastrophe et des risques climatiques

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 climatiques

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

Catastrophes hydrologiques

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

Commentaires:

The technology copes very well with floods as the construction is embedded in the sand and thus very well protected.

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 technology has limited running and maintenance costs once its done fairly well.

6.5 Adoption de la Technologie

• 1-10%

Parmi tous ceux qui ont adopté la Technologie, combien d'entre eux l'ont fait spontanément, à savoir sans recevoir aucune incitation matérielle ou aucun paiement?

• 0-10%

6.6 Adaptation

La Technologie a-t-elle été récemment modifiée pour s'adapter à l'évolution des conditions?

Non

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
The technology created opportunity to graze in wet season grazing areas for an averge extra 2 months period after rainy seasons. The technology has provided additional water that gave herders extra days to graze in wet season areas and utilize the pasture that would have been unutilized due to water constrains. In so doing, the land users utilized the pasture without retreating to traditional dry season grazing areas.
The extra grazing months has reduced overall livestock mortality during droughts and also improved resilience of pastoral community.
The distance travelled and effort required to access water was reduced. Community members reported reduced distances covered and time spent in search of water for livestock. In some instances the distance reduced from 12-15 Km to 3 Km. Community members also mentioned reduction in conflict incidences over water resources in some areas due to adequate supply of water as a result of construction of water infrastructure.
The balanced utilization of the grazing area through SSD water provision, enables herd to graze in wet season grazing for slightly longer period and utilize pasture optimally, this however, does not mean that during that garzing period, there will be overgrazing. The volume of water available restricts the number of animals sustained by the grazing area.

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
The technology has created an opportunity to optimally use the grazing area and overall reduced land degradation. The technology Improves access to water for livestock in ways which promote more sustainable management of rangeland resources and as such strengthening the resilience of local communities.
The validation process prior to construction of the SSD is draws critical lessons of identifying and agreeing on where to construct the SSD in a way that fit within broader sustainable rangeland management in a manner that ensured sustainable and efficient utilization of pasture and browse resources in targeted areas. The increase in water supply allowed livestock to graze additional 2-3 months in target areas before shifting to dry grazing areas where previously they migrated before exhausting the pasture and browse resources due to water scarcity. The dry season grazing area is towards Merti, in Kom and Sabarwawa where there are deep boreholes, under, lock and key and only opened during dry seasons. In typical year, the dry season period is about 7 months. But when one rain season fail it goes to about 11 months.

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?
When the construction season for SSD is not well planned, there is likelihood/risks of the dams being washed away by flash floods.	Better planning and timing of the development of SDD, just slightly before the onset of rainfall.

7.1 Méthodes/ sources d'information

7.3 Liens vers les informations pertinentes disponibles en ligne

Titre/ description:

Promoting resilience by influencing water infrastructure development in community managed rangelands of Kenya

URL:

https://portals.iucn.org/library/sites/library/files/documents/2014-088.pdf

Titre/ description:

Balancing water infrastructure in community-managed rangelands in the arid and semi-arid lands of Kenya

URL:

https://portals.iucn.org/library/sites/library/files/documents/2014-089.pdf