Irrigation Engineering Agricultural Engineerng Hydraulic Engineering Water Resources Engineering Water Resources and Irrigation Management Water Supply Engineering. soil resources and Watershed management. natural resources managements plant science departments can share this materials on the concepts of irrigation aplication techniques. this material include:- surface irrigation, subsurface irrigation, pressurized irrigation. specifically under surface irrigation it discuss it's type, advantage, disadvantage, limitation, layout, constructionon and efficiency determination system. under pressurized irrigation system; the type of pressurized irrigation system, it's components, layout, construction techniques and irrigating techniques was discussed.

1. IRRIGATION SYSTEM
For surveying Engineering students
BY:- Hailu Mosisa (MSc, Irrigation Engineer)
hailumosisa73@gmail.com
Chapter three

5. Out-line
 Irrigation methods
 Surface/gravitational irrigation methods
 Furrow irrigation
 Basin irrigation
 Border irrigation

6. 3.1. Surface Irrigation Method
 Water is applied by gravity across the soil surface
 It accounts about 90% of the whole irrigated area in the
world
 Water is applied to the field in either the controlled or
uncontrolled manner
 Controlled: Water is applied from the head ditch and
guided by corrugations, furrows, borders, or ridges
 Uncontrolled: Wild flooding

7. Cont’d…
 Types of surface irrigation systems



8. Cont’d…
3.1.1 Basin Irrigation System


10. Basin irrigation
 In basin irrigation, water is flooded in wider areas.
 It is ideal for irrigating rice.
 The area is normally flat.
 a very high stream size is introduced into the basin so that rapid
movement of water is obtained.
 The opportunity time difference between the upward and the
downward ends are reduced.

11. Cont’d…
Basin Layout and construction
 Basin layout refers
 to the shape and size of basins and
 to the shape and size of the bunds
I. Shape and size of basins
 The shape and size of basins are mainly determined by
 the land slope,
 the soil type,
 the available stream size (the water flow to the basin),
 the required depth of the irrigation application and
 farming practices

12. Cont’d…
BASIN WIDTH
 The main limitation on the width of a basin is the land
slope
 If the land slope is steep,
 the basin should be narrow; otherwise too much earth movement
will be needed to obtain level basins
 Three other factors which may affect basin width are:
 Depth of fertile soil,
 Method of basin construction,
 Agricultural practices

13. Cont’d…
 approximate value for the maximum basin or
terrace width (m)

14. Cont’d…
BASIN SIZE
 The size of basins depends on the slope, on the soil type and
the available water flow to the basins
 The relationship between soil type, stream size and size of the
basin is given in Table

15. Cont’d…
II. Shape and dimensions of bunds
 are small earth embankments which contain irrigation water
within basins
 sometimes called ridges, dykes or levees
 The height of bunds is determined by the irrigation depth and
the freeboard
 freeboard is the height above the irrigation depth to be sure that
water will not overtop the bund
 bunds may be grouped as
 Temporary bunds and
 Permanent bunds

16. Cont’d…
1. Temporary bunds
 normally 60-120 cm wide at the base and
 have a height of 15-30 cm above the original ground surface,
including a freeboard of 10 cm
 surround fields on which annual crops are grown;
 these bunds are rebuilt each season
 used to subdivide the various fields further


17. Cont’d…
2. Permanent bunds
 have a base width of 130-160 cm and a height of 60-90 cm when
constructed
 The settled height will be 40-50 cm
 are mostly used in rice cultivation, where the same crop is
planted on the same fields year after year
 are used as paths in the rice fields as well

18. Cont’d…
Basin Construction
 steps which are involved in the construction of basins:
 setting out;
 forming the bunds; and
 smoothing the land within the basins
Step 1. setting out
 Before construction can begin the location of the basins and bunds
must be set out on the ground
 using pegs, string lines or chalk powder to mark the lines of the bunds
 On flat land basins
 may be square or rectangular in shape
 On sloping or undulating land basins
 may be irregular in shape and terracing required

19. Cont’d…

20. Cont’d…
Step 2. Forming the bunds
 Both temporary and permanent bunds can be formed by hand
labour or by animal or tractor powered equipment
 When soil is gathered from an area close to the bund a 'borrow-
furrow' is formed
 A useful piece of equipment for forming bunds is an A-frame
 A-frame suitable for drawing by animals has blades 20
cm deep and
2 m long spaced 1.5 m apart at the front and 30 cm apart at the rear

21. Cont’d…


22. Cont’d
 Step 3: Smoothing the land
 This can be the most difficult part of basin construction and
involves very careful levelling of the land within each basin
 This can be done by hand or by a tractor-drawn land plane
depending on the size of the basin
 On sloping land, where terraces are constructed, levelling is
achieved by moving soil from the upper part of the slope to the
lower part
 Care is needed when filling in the borrow furrow to ensure the bund
height is maintained so that overtopping is avoided

23. Cont’d
Irrigating Basins
 There are two methods to supply irrigation water to basins:
 the direct method and the cascade method
1. The direct method
 Irrigation water is led directly from the field channel into the basin through siphons or
bund breaks
2. The cascade method
 On sloping land, where terraces are used, the irrigation water is supplied to the highest
terrace, and then allowed to flow to a lower terrace and so on
 This is a good method to use for paddy rice on clay soils where
percolation and seepage losses are low
 However, for other crops on sandy or loamy soils, percolation
losses can be excessive while water is flowing through the upper
terraces to irrigate the lower ones

24. Cont’d
Basins area should be small if the:
1. Slope of the land is steep.
2. Soil is sandy.
3. Stream size to the basin is small.
4. Required depth of the irrigation application is small.
5. Field preparation is done by hand or animal.
Basins can be large if the:
1. Slope of the land is gentle or flat.
2. Soil is clay.
3. Stream size to the basin is large.
4. Required depth of the irrigation application is large.
5. Field preparation is mechanized

25. If any question and suggestion!!!