1. 1.2 Typology of spate irrigation systems

2. Typology Size of the systems Type of infrastructure
Type of operation and maintenance
Source of water
Duration and frequency of floods

3. Size of the systems Small Medium Large/ Mega
From few hectares to 500 hectares
Short duration floods
On tributary streams in mountains
Considerable slope
Small intermontane aquifer sometimes
Single farmer or single group
Usually no interventions
Gravel and stone deposits
Medium
Up to 3000 ha
Well defined water rights
Relatively short floods
Coastal, inner basins and smaller stream
Smaller catchment – lower reliability
Some unsuccessful modern civil engineering
Uniform sedimentation
Large/ Mega
Up to ha - multiple off takes of ephemeral rivers
Longer floods, semi-perennial flows
Flat gradients, delicate water sharing arrangements and water rights
Some “modernization” efforts – but usually ineffective – bulldozer support very important
Mixed sedimentation

4. Type of infrastructure
Traditional
Deflection spurs or bunds
Earthen, stone or brushwood structures
Typically many small intakes with short canals
Improved traditional
Reinforced intakes, bed stabilizer, rejection spill ways or overflow structures, drop structures
Use of gabions, bulldozer bunds, vegetative bunds
Traditional channel network kept intact
Modernized
Concrete diversion weirs, sedimentation ponds, single long channels
Use of concrete and gabion
Often modified by farmers

5. Type of organization Traditional
Farmers manage without assistance from outside agencies
Joint management by farmers and local government
Support by local government – usually in regulating water distribution, undertaking part of the maintenance, providing for instance bulldozer
Agency managed
(not so much in Pakistan)
Managed by government organizations – usually after ‘modernization’
Nowadays these systems are often handed back to farmer organizations

6. Source of water Spate flows only
Much depends on number of spates – this can vary from few (less than 5) to many spate (more than 30)
In systems entirely dependent on spate additional rainfall also becomes an important factor
Additional access to significant base flows
In some systems the total volume under base flow can be more than 50% of entire water volume – this assures in particular cultivation in the upper reaches of the command area, whereas the spate flows are used in middle and lower parts of the command area
Conjunctive use of spate and shallow groundwater
The possibility to use groundwater depends on availability of a shallow aquifer and the quality of groundwater (non saline)
If possible, conjunctive use makes it possible to grow high value crops

7. Duration and frequency of floods
Marginal spate
<3-5 floods
Short duration
High peaks
Spate
5-35 flood events
Short duration (<1 day)
Spread of floods – many moderate floods
Semi-perennial
Discharge for several weeks, months
Not perennial
Some peak flood events