Soil and Water Conservation Works - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 94

0.6 0 m

Borrow Pit

0.75 m

D/s

U/s

3.65 m

4 m

Section of a Contour Bund

Standard Sections of Contour Bund

Section Base Width Top Width Height Section Area

CB-1 2.00 m 0.45 m 0.60 m 0.74 m 2

CB-2 2.00 m 0.45 m 0.75 m 0.93 m 2

CB-3 2.60 m 0.45 m 0.80 m 1.28 m 2

CB-4 3.12 m 0.60 m 0.85 m 1.56 m 2

CB-5 4.25 m 0.60 m 0.90 m 2.18 m 2

a Contour bund

Original Ground Profile

1
2 :1

−

Cut Toe

Fill Riser

Bench Can be Level

or With Inward Slope

Cut

Fill

Section of Bench Terraces

Design of Bench Terraces

Vertical interval for bench terraces can be calculated from this formula:

ws

where w is width of bench s is ground slope
expressed as a fraction, and b is riser batter (0.50)

v =

s

2b −

Length of terrace is determined by the drainage lines, since the terrace
should be continuous along contour as far as possible.
Inward grade or slope should be kept from 2% to 5%.

b Bench terrace

Fig. 5.4 Details of contour bund