Bunds are embankment structures constructed across land slopes to obstruct surface runoff. There are two main types: contour bunds and graded bunds. Contour bunds have no longitudinal slope and are suitable for areas with annual rainfall under 600 mm and permeable soils with slopes less than 6%. Graded bunds have a slope to safely dispose of excess runoff and are recommended for high rainfall regions and impermeable soils. The design of bunds considers factors like rainfall, soil type, slope, spacing between bunds, size, length, and area lost due to construction.

1. BUNDS AND THEIR DESIGN
PRESENTATION BY
UTKARSH JAIN

2. BUNDS
 USED FOR OBSTRUCTING PATH OF SURFACE RUNOFF.
 ARE EMBANKMENT LIKE STRUCTURES.
 CONSTRUCTED ACROSS LAND SLOPE.
 BUNDS ARE OF TWO TYPES:
1. CONTOUR BUNDS
2. GRADED BUNDS

3. CONTOUR BUNDS
 RECOMMENDATION: 1.ANNUAL RAINFALL<600 MM
2.PERMABLE SOIL WITH LAND SLOPE < 6% .
 NO LONGITUDNAL SLOPE IS PROVIDED TO FIELD STRIP
.
 WHY?? TO MAXIMISE CONSERVATION.

4. CONTOUR BUNDS
 FUNCTIONS
 TO REDUCE LENGTH OF SLOPE.
 TO RECHARGE WATER WHICH HELP IN CROP CULTIVATION.
 LIMITATIONS
 ONLY SUITABLE FOR AREAS WITH RAINFALL<600 MM.
 UNSUITABLE FOR CLAYEY SOILS.
 NOT SUITABLE FOR SLOPES >6%

5. GRADED BUNDS
 CONSTRUCTED WITH SOME SLOPE.
 USED FOR SAFE DISPOSAL OF EXCESS RUNOFF.
 RECOMMENDED FOR HIGH RAINFALL REGION & RELATIVELY
IMPERMEABLE SOIL.
 ARE OF 2 TYPES : UNIFORMLY GRADED AND VARIABLE GRADED.

6. GRADED BUNDS
 UNIFORMLY GRADED BUNDS.
 SUITABLE IN AREAS WHERE:
1. BUNDS NEED SHORTER LENGTH.
2. RUNOFF IS LOW.
 VARIABLE GRADED BUNDS.
 SUITABLE IN AREAS WHERE:
1. BUNDS NEED LONGER LENGTH.
2. RUNOFF IS MORE

7. DESIGN SPECIFICATION OF BUNDS
1.TYPE OF BUNDS.
 DEPENDS OF RAINFALL & SOIL CONDITIONS.
2. SPACING BETWEEN BUNDS.
 DETERMINED AS FOLLOWS.
 V.I= (S/A)+ B/1
 HERE V.I = VERTICAL INTERVAL B/W BUNDS
 B = SLOPE %
 A & B = CONSTANTS.

8. DESIGN SPECIFICATION OF BUNDS
2. SPACING OF BUNDS.
 MODIFICATION
 FOR HEAVY RAINFALL
 V.I = 10*S + 60
 FOR LOW RAINFALL
 V.I = 15*S +60
 RELN B/W HORIZONTAL AND VERTICAL SPACING
 H.I = V.I /S

9. DESIGN SPECIFICATION OF BUNDS
3.SIZE OF BUNDS.
 INCLUDES: HEIGHT, TOP WIDTH,SIDE SLOPES & BOTTOM WIDTH.
 HEIGHT OF BUNDS DEPENDS UPON :
A.SLOPE OF LAND .
B. SPACING OF BUNDS.
C.MAXIMUM RAINFALL EXPECTED IN THE AREA.
 ONCE HEIGHT IS DETERMINED OTHER FACTORS CAN BE DETERMINED BY
USING INFO. OF NATURE OF SOIL.

10. DESIGN SPECIFICATION OF BUNDS
3.SIZE OF BUND.
 HEIGHT CAN BE CALCULATED BY THE EQUATION
 X = SQRT(3V/10).
 WHEN LAND SLOPE IS EXPRESSED IN S PERCENT.
 THUS , V=LS/100.
 THUS, X = SQRT (3LS/1000).
 HERE,X= HEIGHT OF BUND. V= VERTICAL INT. B/W BUNDS
L=DISTANCE B/W BUNDS

12. DESIGN SPECIFICATION OF BUNDS
4.LENGTH OF BUND.
 DETERMINED BY: CALCULATING HORIZONTAL INTERVAL B/ BUNDS.
 GIVEN BY : L = 10000/H.I = 10000*S/V.I*100
 THUS ,L= 100(S/V.I).
5. EARTHWORK.
 INCLUDES SUM OF EATHWORK.
 EARHWORK IS DONE IN MAIN BUNDS,SIDE BUNDS & LATERAL BUNDS.
 ET=EM+ES+EL.

13. DESIGN SPECIFICATION OF BUNDS
6.AREA LOST DUE TO BUNDING.
 CALCULATED BY THE EQN.
 AL = 10000/H.I*B.
 AL = 100S/V.I*B.
 HERE B = BASE WIDTH OF BUND.
 EQN TELLS ONLY AREA LOST TO MAIN CONTOUR

14. DESIGN SPECIFICATION OF BUNDS.
6. AREA LOST DUE TO BUNDING.
 AREA LOST IN SIDE AND LATERAL BUNDS IS GIVEN BY :
 AL=1.3*(100*S*B/V.I)