social and environmental benefits of spate irrigation development 1.5
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SOCIAL AND ENVIRONMENTAL BENEFITS OF SPATE IRRIGATION DEVELOPMENT
1.5
Social benefits
In many areas spate flows are the only sourceof water – so livelihoods depends on the abilityto control the floods and store the water
Livelihood impacts and social benefits
Social benefits of spate irrigationGeneral:
• Poverty alleviation• Improvement of food security• Improvement of local economy• Creation of labour opportunities• Reduction in seasonal migration
Specific:• Domestic water for human beings• Drinking water for livestock• Forest and rangeland• Source of building material
]Domestic water
Domestic water supply – especially wheregroundwater is not available or useable (saline):Wells in ephemeral riverbeds
Livelihood impacts :Water supply for livestock
Zizyphus:The Miracle Tree
Source of woodWood for implements, construction, timber, fruits
In several areas part of the spate flows used for irrigating forest or
rangeland
Improving social benefits:domestic water supply
• Improved wells• Subsurface dams• Sand dams• Plastic lined ponds
Improved wells
Subsurface dams
Constructing subsurface dam
Subsurface dam “at work”
Plastic lined ponds and filters
Source of building material
Mud
Sand
Environmental impacts
Environmental benefits of spate irrigation
• “Fixes” the area and avoids erosion • Maintains large vegetative
biodiversity• Improved structures may reduce
cutting of trees/shrubs for traditional structures
Maintaining the spate system in area prevents excessive gully-ing, erosion, changes in river morphology,wind erosion and the return of the area to desert situation
Alternatively, the destruction of a downstream riverain forest in thisarea (Yandafero, Ethiopia) caused the river to change to a lower courseand cause a massive decline in the river bed levels in this area, making it almost impossible to divert water from the river
The vegative biodiversity in spate irrigation system is often very large,as seeds are transported over a large area by the floods and ‘dumped’ and left to germinate in the moist soil of the spate systems
Traditional brushwood structures put a huge demand on localvegetation in usually fragile environment – replacing them with improved structures reduces deforestation